Coronary Circulation

The purpose of this study was to evaluate the therapeutic efficacy of the combined growth factor therapy with an omental flap in a rabbit model of chronic myocardial ischemia. Methods: Chronic ischemia was created in rabbits by placing a constrictor on the left circumflex artery. Four weeks later the animals were divided into 3 groups: group FG, in which a gelatin hydrogel sheet incorporating 100 g of basic fibroblast growth factor was placed over the left circumflex region followed by covering with the omental flap including the intact gastroepiploic artery; group F, in which only the basic fibroblast growth factor sheet was placed; and group N, in which no treatment was done. Results: Cine magnetic resonance imaging analysis showed a greater percentage wall thickening in the left circumflex region in group FG than in other groups (group FG, 49.2% Ϯ 4.5%; group F, 41.2% Ϯ 3.8%; group N, 32.1% Ϯ 2.5%, P ϭ.035, group FG vs group F). A colored microsphere assay showed higher perfusion in the left circumflex region in group FG than in group F. Perfusion in the left circumflex region was decreased after clamping the gastroepiploic artery pedicle in group FG (before clamping, 2.83 Ϯ 0.72 mL • min Ϫ1 • g Ϫ1 ; after clamping, 1.93 Ϯ 0.59 mL • min Ϫ1 • g Ϫ1 ; P Ͻ .01). In vivo angiography via gastroepiploic artery showed direct "to-and-fro" visible collaterals between the gastroepiploic and occluded left circumflex coronary arteries in group FG. The combined growth factor therapy with an omental flap induced arteriogenesis and provided additional perfusion via the gastroepiploic artery to ameliorate regional dysfunction in the chronically ischemic myocardium.

Objective: The number of viable transplanted cells in the heart is sharply decreased shortly after cell injection. The exact mechanics of cell loss are unclear. We hypothesized that immature cardiac cells transplanted directly into rat heart could be washed out via the cardiac vasculature, and carried to other organs. Methods: Female Fischer rats were subjected to 60 min of coronary artery occlusion followed by 3 h of reperfusion (OR group) or 4 h or permanent coronary artery occlusion (PO group). Neonatal rat cardiac cells (5 Â 10 6 ) were injected directly into the free wall of the left ventricle at either 15 min post-reperfusion (OR group) or 75 min after occlusion (PO group). At the end of the protocol, a histological analysis for transplanted cells in the heart (i.e. microscopic examination for cells in approximately 790 histogic fields within each heart) and polymerase chain reaction (PCR)-based determination of the Sry gene (a male cell marker) in the heart and other organs were performed. Results: In the OR group, only 3.39 T 0.69% fields contained immature cells compared to 6.57 T 1.33% fields in the PO group ( p < 0.05). Cardiac blood vessels contained round, immature cardiomyocytes. PCR analysis revealed that 100% of the animals (5 of 5) in both groups had cells present in their hearts and lungs, 40% of the OR group and 60% of the PO group demonstrated cells in the liver and kidneys, and 40% of the PO group had cells in the spleen. Conclusion: Neonatal cardiomyocytes injected directly into the area at risk of the heart escape acutely from the infract to other organs through the vascular system of the heart; loss of cells is more prominent with reperfusion.

1) Anatomía y Fisiología cardíacas (son conceptos que siempre caen porque las preguntas de Anatomía y Fisiología suelen sacarlas de Cardio, Pneumo, Digestivo y Nefro). 2) Semiología cardíaca. Los ruidos cardíacos, los soplos y los tipos de pulsos. Una pregunta seguro que os cae de semiología. 3) Fármacos que se utilizan para el tratamiento de la insuficiencia cardíaca. 4) Fármacos antiarrítmicos. 5) Fiebre reumática. Sobretodo saberse la clínica, el diagnóstico y el tratamiento. Es una enfermedad que les gusta mucho preguntar. 6) Valvulopatías. Son importantísimas. Suelen caer 2-3 preguntas en forma de caso clínico en el que por la clínica y la exploración (sobretodo el tipo de soplo) tenéis que saber de qué valvulopatía se trata. Son importantes también los tratamientos. 7) Endocarditis. También les encanta preguntarla y la preguntan prácticamente cada año. Hay que estudiarla bién. 8) Dg. diferencial entre pericarditis y taponamiento cardíaco. Síndrome de Dressler. 9) Conocer los diferentes tipos de angina de pecho; la clínica, el dg y el tt. 10) IAM. Es muy importante, sobretodo las enzimas, el diagnóstico de localización, las características según la localización, las complicaciones y el tratamiento. 11) Tratamiento de la HTA. Alguna pregunta puede salir por Farmacología. 1) Alteraciones que se producen en el ECG las diferentes enfermedades. 2) Características más importantes de las principales arrítmias. 3) Principales características de las miocardiopatias. 4) Patología de la aorta torácica. 1. ANATOMÍA Las arterias coronarias nacen en la raíz de la arteria aorta, a nivel de los senos de Valsalva: • Arteria Coronaria Izquierda (nace en el seno de Valsalva izquierdo), formando el tronco común que se divide en: ♦ Descendente anterior (recorre el surco interventricular anterior llegando al ápex). De ésta se desprenden ramas: ̇ Septales: Irrigan los 2/3 anteriores del tabique interventricular ̇ Diagonales: irrigan la pared ventricular anterior ♦ Circunfleja (recorre el surco aurículo-ventricular izquierdo para dar la vuelta al corazón). Irriga: aurícula izquierda, tabique interventricular y fascículo de His. Da ramas: ̇ Auriculares: irriga gran parte de aurículas y tabique interauricular. Marginales: que irriga pared lateral del ventrículo izdo. • Coronaria derecha (C.D.): nace del seno de Valsalva derecho, transcurre entre arteria Pulmonar y la aurícula derecha, recorre surco auriculoventricular derecho. Da las ramas: ♦ Auriculares: irrigan aurícula derecha. Arteria del nodo sinusal. ♦ Ventriculares: irrigan el ventrículo derecho, 1/3 posterior del tabique interventricular y la parte vecina de la pared posterior e inferior del ventrículo izquierdo. Dominancia coronaria: hablamos de dominancia izquierda o derecha en función de cual de las dos coronarias originan la arteria descendente posterior, que irriga la cara posterior del corazón; en más del 60% de los casos es la coronaria derecha (dominancia derecha), mientras que en el resto es la arteria circunfleja (dominancia izquierda). CARACTERÍSTICAS DE LA CIRCULACIÓN CORONARIA: • El flujo coronario normal es de 80-100 ml/100g tejido miocárdico, que puede incrementarse hasta 300-400 ml/100 g. • Diferencia arterio-venosa de O 2 es del 75 % (mientras que en el resto del organismo es del 25 %). Esto da lugar a un mecanismo de escasas posibilidades de compensación ante un aumento de la demanda de oxígeno. • El flujo coronario es fundamentalmente durante la diástole. • Hay 2 tipos de vasos coronarios: ♦ De conductancia (grandes troncos y ramas) de localización epicárdica. ♦ De resistencia, intramiocárdicos. • Mecánicos: flujo coronario = TA s aórtica/R distales • Porque la válvula aórtica (o pulmonar) se abre de golpe con altas presiones emitiendo un sonido "metálico". • Causas: estenosis aórtica (no calcificada), válvula bicúspide, estenosis pulmonar, hipertensión pulmonar, dilatación idiopática de la arteria pulmonar. -Coincide con la contracción isovolumetrica. EM IM Bloqueo rama derecha. -Bloqueo rama izquierda. -EM grave. -Mixoma de aurícula izquierda. R 2 -Cierre AO2 + P2. -Separa la protodiástole de la fase de relajación isovolumetrica. EAO EP HTP Bloq. Rama derecha. TEP CIV CIA* -Bloqueo rama izquierda. -EAO -Obstrucción con flujo aórtico. Normal en niños y cuando ç GC. Si > 40 a: -Descompensación ventricular. -Regurgitación AV. Contracción auricular (siempre patológica). Ausente si fibrilación auricular. Presente en: HTA, miocardiopt. Hipertrófica, coronariopatía, IM agudo. *CIA: desdoblamiento fijo del 2º mido (no ç con la inspiración). G. Clic Mesosistólico: Sd de Barlow o Prolapso mitral. Los soplos cardíacos se estudiarán mejor en cada una de las patologías causales, pero esquemáticamente los más importantes, son: • Inocentes: soplo de Still. Mesosistólico. • Pansistólico: insuficiencia mitral, insuficiencia tricuspidea, comunicación interventricular. • Protosistólico: comunicación interventricular pequeña. • Mesosistólicos: estenosis aórtica, estenosis pulmonar, hiperaflujo (insuficiencia aórtica, insuficiencia pulmonar, fiebre, anemia, hipertiroidismo). • Telesistólicos: prolapso mitral, coartación de aorta (a veces). • Protodiastólicos: insuficiencia aórtica, insuficiencia pulmonar, Graham-Stell (hipertensión pulmonar). • Meso-Tedediastólicos: estenosis mitral, estenosis tricuspidea (arrastre presistólico), mixoma auricular, soplo de Austin-Flint, soplo de Carey-Coombs. 9 • Persistencia del conducto arterioso (Gibson), fístulas arterio-venosas sistémicas, conexiones aorto-pulmonares, comunicación seno de Valsalva con ventrículo derecho, coartación de aorta, tromboembolismo pulmonar. • Maniobra de Valsalva (disminuye precarga): sólo aumenta el soplo de la miocardiopatía hipertrófica y el prolapso mitral, mientras que disminuye los demás. • Bipedestación: sólo aumenta soplo de la miocardiopatía hipertrófica obstructiva y el prolapso mitral. • Cuclillas: aumenta la mayoría soplos excepto miocardiopatía hipertrófica obstructiva el prolapso mitral. • Pulso Pequeño (PARVUS): volumen eyección disminuido (hipovolemia, insuficiencia cardíaca izquierda, estenosis mitral, pericarditis constrictiva, taponamiento cardíaco). • Pulso Filiforme: no palpable (shock). • Pulso Pequeño y Retrasado (PARVUS Y TARDUS): estenosis aórtica severa. • Pulso Amplio y Saltón: se produce por un volumen de eyección elevado con resistencias periféricas disminuidas. Sus causas son: insuficiencia aórtica, persistencia del ductus arterioso, estados hipercinéticos (anemia, hipertiroidismo, beri-beri), bloqueo A-V completo. • Pulso Bisferiens: dilatación aórtica, insuficiencia aórtica, miocardiopatía hipertrófica obstructiva. • Pulso Alternante: insuficiencia ventricular izquierda severa. • Pulso Bigémino: latido normal que alterna con extrasístole, intoxicación por digital o nerviosismo (por extrasístoles). • Pulso Paradójico: debido a una reducción del volumen sistólico del ventrículo izquierdo y a la transmisión de la presión negativa intratorácia a la aorta, que hace disminuir la TA S más de 10 mmHg con la inspiración. Se ve en el taponamiento cardíaco (70-90%), pericarditis constrictiva (40%), bronquitis crónica, obesidad extrema, asma bronquial, enfisema, shock hipovolémico, embolia pulmonar, embarazo.

To evaluate the relative long-term improvement in coronary artery hemodynamics after revascularization by coronary artery bypass graft surgery (CABG) or percutaneous transluminal coronary angioplasty (PTCA), regional coronary flow reserve (CFR) was measured, by digital computer analysis of 35 mm cine film, in 50 men undergoing cardiac catheterization. CFR (mean +/- SEM) in 12 atherosclerotic arteries before revascularization was 1.02 +/- 0.05. Mean CFR in 29 normal arteries of men with normal coronary arteriograms was significantly higher (2.59 +/- 0.11) than that in 16 atherosclerotic arteries of patients revascularized by CABG (2.02 +/- 0.17, p less than .01) or in 14 atherosclerotic arteries of those revascularized by PTCA (1.97 +/- 0.12, p less than .01). No difference in CFR between the CABG and PTCA groups was found and variables known to influence CFR were similar between groups. Equivalent and significant long-term improvement in coronary artery hemodynamics is provided by C...

BACKGROUND At any given perfusion pressure, coronary reserve is expressed by the difference between autoregulated and maximally vasodilated flow. In hypertension the raised coronary resistance reduces the steepness of the pressure-flow relationship at maximal vasodilatation. In the presence of cardiac hypertrophy the line of autoregulated flow becomes higher. For these reasons coronary reserve is reduced and the point at which baseline flow approaches the maximal achievable flow might be shifted to a higher perfusion pressure. Thus, any reduction below this elevated and critical value of pressure would lower the coronary flow. METHODS AND RESULTS The investigated patients were normotensive (controls, nine) and hypertensive with normal (group I, seven) or augmented LV mass index because of concentric LV hypertrophy (group II, eight). All had effort-induced angina and angiographically normal left epicardial branches. Flow in the great cardiac vein was measured by thermodilution in the...

Physiological functions (e.g., cerebral blood fl ow, glucose metabolism, and neuroreceptor binding) can be investigated as parameters estimated by kinetic modeling using dynamic positron emission tomography (PET) images. Imaging of these physiological parameters, called parametric imaging, can locate the regional distribution of functionalities. However, the most serious technical issue affecting parametric imaging is noise in dynamic PET data. This review describes wavelet denoising of dynamic PET images for improving image quality in estimated parametric images. Wavelet denoising provides signifi cantly improved quality directly to dynamic PET images and indirectly to estimated parametric images. The application of wavelet denoising to radioligand and kinetic analysis is still in the development stage, but even so, it is thought that wavelet techniques will have a substantial impact on nuclear medicine in the near future.

cardiopulmonary bypass on the pulmonary vasculature and the developing neonatal brain. Closure of the AP window was a requisite measure to reduce the symptoms of heart failure in this patient. Increasing restriction at the level of a VSD in patients with tricuspid atresia may be due to dynamic or mechanical obstruction or as a consequence of alteration in ventricular geometry following volume unloading surgery, as described in congenital heart defects with the double inlet left ventricle or tricuspid atresia with the VSD and transposition of the great arteries . We believe that the AP window ligation, though providing an adequate initial first step for single ventricle surgical palliation, may have decreased the volume load to the left ventricle in our patient, thus adding to the evolving subpulmonary stenosis, and may have contributed to the need for the Blalock-Taussig shunt. However, alternative approaches such as the previously described fenestrated repair of the AP window [1] would leave multiple sources of pulmonary blood flow with their unpredictability; or complete separation of the pulmonary circulation with the addition of systemic-to-pulmonary shunt would leave the child shunt-dependent. Additionally, both approaches would require the use of cardiopulmonary bypass and add to the complexity of the procedure. Our surgical approach to AP window closure was initially successful; however, the progression of disease resulted in the need for an additional surgical palliative procedure. In summary, our experience highlights the complexities in the management of neonates with such complex single ventricle disease. eComment. Balancing the pulmonary circulation in tricuspid atresia with an aortopulmonary window

In some pathological conditions like aortic stiffening and calcific aortic stenosis (CAS), the microstructure of the aortic root and the aortic valve leaflets are altered in response to stress resulting in changes in tissue thickness, stiffness, or both. This aortic stiffening and CAS are thought to affect coronary blood flow. The goal of the present paper was to include the flow in the coronary ostia in the previous fluid structure interaction model we have developed and to analyze the effect of diseased tissues (aortic root stiffening and CAS) on coronary perfusion. Results revealed a significant impact on the coronary perfusion due to a moderate increase in the aortic wall stiffness and CAS (increase of the aortic valve leaflets thickness). A marked drop of coronary peak velocity occurred when the values of leaflet thickness and aortic wall stiffness were above a certain threshold, corresponding to a threefold of their normal value. Consequently, mild and prophylactic treatments such as smoking cessation, exercise, or diet, which have been proven to increase the aortic compliance, may significantly improve the coronary perfusion.

In some pathological conditions like aortic stiffening and calcific aortic stenosis (CAS), the microstructure of the aortic root and the aortic valve leaflets are altered in response to stress resulting in changes in tissue thickness, stiffness, or both. This aortic stiffening and CAS are thought to affect coronary blood flow. The goal of the present paper was to include the flow in the coronary ostia in the previous fluid structure interaction model we have developed and to analyze the effect of diseased tissues (aortic root stiffening and CAS) on coronary perfusion. Results revealed a significant impact on the coronary perfusion due to a moderate increase in the aortic wall stiffness and CAS (increase of the aortic valve leaflets thickness). A marked drop of coronary peak velocity occurred when the values of leaflet thickness and aortic wall stiffness were above a certain threshold, corresponding to a threefold of their normal value. Consequently, mild and prophylactic treatments ...

. We compared dipyridamole technetium-99m (Tc-99m) tetrofosmin and thallium-201 (Tl-201) single-photon emission computed tomographic (SPECT) imaging with respect to the detection rate of perfusion abnormalities in 26 patients with angiographic coronary artery disease (CAD). Background. Experimental studies have shown that myocardial extraction of Tc-99m tetrofosmin is lower than that of Tl-201 at high flow rates, resulting in less severe defects with vasodilator stress. It is uncertain whether this results in a lower sensitivity than Tl-201 for detecting coronary stenoses with vasodilator stress in patients. Methods. Twenty-six patients with CAD underwent both dipyridamole Tl-201 and Tc-99m tetrofosmin SPECT. Tomographic images were scored for initial defects and the presence of reversibility. Defect magnitude was computer quantitated. Results. Of the 26 patients, 25 had defects on both Tl-201 and Tc-99m tetrofosmin SPECT images. Of 340 segments analyzed, 102 had defects by Tl-201 and 92 by Tc-99m tetrofosmin (p ‫؍‬ NS). Whereas Tl-201 detected 27 fixed defects in 12 patients, Tc-99m tetrofosmin identified 37 fixed defects in 14 patients (p ‫؍‬ NS). In contrast, Tl-201 identified more reversible and partially reversible defects than did Tc-99m tetrofosmin (89 vs. 55, p ‫؍‬ 0.002). The average defect magnitude (percent normal) was similar for defects concordantly graded as fixed (38 ؎ 3.0% for Tl-201 vs. 42 ؎ 4% [mean ؎ SEM] for Tc-99m tetrofosmin, p ‫؍‬ NS). The average defect magnitude for defects concordantly graded as completely reversible was significantly more severe on Tl-201 than on Tc-99m tetrofosmin (49 ؎ 3% vs. 58 ؎ 3%) SPECT images. A significantly greater defect magnitude for Tl-201 was also found for defects concordantly classified as partly reversible (30 ؎ 4% for Tl-201 vs. 45 ؎ 5% for Tc-99m tetrofosmin). Conclusions. With dipyridamole stress, 1) at least one defect was seen on both Tl-201 and Tc-99m tetrofosmin SPECT images; 2) Tc-99m tetrofosmin SPECT identified fewer reversible defects than did Tl-201, but showed a similar number of fixed defects; 3) the magnitude of reversible defects seen on Tc-99m tetrofosmin images was less, whereas fixed defects were similar for both tracers; 4) reversible defects seen on Tl-201 and not on Tc-99m tetrofosmin SPECT images were predominantly regions perfused by mild coronary stenoses.

Surgical strategy to construct a two-coronary system for a patient with anomalous origin of left coronary artery from pulmonary artery (ALCAPA) has evolved with time. Limited long-term follow-up data are available on these children. We report population-based follow-up in children operated on for ALCAPA. In total, 29 patients underwent aortic reimplantation of ALCAPA between 1979 and 2006. Twenty (69%) children were repaired with direct aortic implantation, five (17%) with a modified tubular extension technique, and four (14%) patients with an intrapulmonary baffling technique. Early postoperative mortality (&lt;30 days) was 17%. No late mortality (&gt;30 days) was detected. The median length of follow-up was 11 years (range 10 months-27 years). Global left ventricular function by echocardiography (M-mode) was within normal limits (&gt;30%) in all patients one year after operation. Functionally, 80% of patients were classified in NYHA class I, 20% in NYHA II, and 0% in NYHA classes ...

The L‐arginine derivatives NG‐nitro‐L‐arginine (L‐NOARG) and NG‐nitro‐L‐arginine methyl ester (L‐NAME) have been widely used to inhibit constitutive NO synthase (NOS) in different biological systems. This work was carried out to investigate whether L‐NAME is a direct inhibitor of NOS or requires preceding hydrolytic bioactivation to L‐NOARG for inhibition of the enzyme. A bolus of L‐NAME and L‐NOARG (0.25 μmol) increased coronary perfusion pressure of rat isolated hearts to the same extent (21 ± 0.8 mmHg; n = 5), but the effect developed more rapidly following addition of L‐NOARG than L‐NAME (mean half‐time: 0.7 vs. 4.2 min). The time‐dependent onset of the inhibitory effect of L‐NAME was paralleled by the appearance of L‐NOARG in the coronary effluent. Freshly dissolved L‐NAME was a 50 fold less potent inhibitor of purified brain NOS (mean IC50 = 70 μm) than L‐NOARG (IC50 = 1.4 μm), but the apparent inhibitory potency of L‐NAME approached that of L‐NOARG upon prolonged incubation a...

Objective: Vertical plication of the atrialized chamber in Ebstein malformation has been subject to debate. A major argument against it is risk of coronary arterial injury; however, the coronary anatomy in the malformation remains incompletely investigated. We examined 17 autopsied hearts with the malformation. Special attention was paid to the coronary blood supply of the right ventricular inferior wall, focusing on the course of the posterior descending branch and its relationship with the interventricular septum. Results: The right coronary artery was dominant in 11 cases (65%); the remaining 6 had left dominance. In 6 right-dominant hearts , the right coronary artery gave rise to the branch before reaching the crux of the heart. This early takeoff caused the entire branch to be deviated rightward. Another 2 right-dominant hearts showed rightward deviation of the branch course after an initial short segment along the septum. In contrast, in 2 left-dominant hearts, the left circumflex artery ran beyond the crux and then gave rise to the branch, again resulting in rightward deviation of the branch. These deviations allowed the branch to run on the thin walled part of the right ventricular inferior wall where endocardial stitches are placed during typical vertical plication. The posterior descending branch was frequently (10/17, 59%) deviated toward the right side relative to the interventricular septum in hearts with Ebstein malformation. Because of this and the thinness of the atrialized ventricular wall, care should be taken to the branch even with superficial endothelial stitches.

Epoxyeicosatrienoic acids (EETs), which function primarily as autocrine and paracrine mediators in the cardiovascular and renal systems, are synthesized from arachidonic acid by cytochrome P-450 epoxygenases. They activate smooth muscle large-conductance Ca 2ϩ -activated K ϩ channels, producing hyperpolarization and vasorelaxation. EETs also have anti-inflammatory effects in the vasculature and kidney, stimulate angiogenesis, and have mitogenic effects in the kidney. Many of the functional effects of EETs occur through activation of signal transduction pathways and modulation of gene expression, events probably initiated by binding to a putative cell surface EET receptor. However, EETs are rapidly taken up by cells and are incorporated into and released from phospholipids, suggesting that some functional effects may occur through a direct interaction between the EET and an intracellular effector system. In this regard, EETs and several of their metabolites activate peroxisome proliferator-activated receptor ␣ (PPAR␣) and PPAR␥, suggesting that some functional effects may result from PPAR activation. EETs are metabolized primarily by conversion to dihydroxyeicosatrienoic acids (DHETs), a reaction catalyzed by soluble epoxide hydrolase (sEH). Many potentially beneficial actions of EETs are attenuated upon conversion to DHETs, which do not appear to be essential under routine conditions. Therefore, sEH is considered a potential therapeutic target for enhancing the beneficial functions of EETs. soluble epoxide hydrolase; eicosanoids; dihydroxyeicosatrienoic acids; cytochrome P-450; peroxisome proliferator-activated receptor The epoxygenases that synthesize EETs are primarily members of the CYP 2C and 2J classes. These enzymes are located in the endoplasmic reticulum, and they utilize arachidonic acid hydrolyzed from phospholipids when the Ca 2ϩ -dependent type IV phospholipase A 2 is activated and translocated from the cytosol to intracellular membranes (53, 60). The CYP epoxygenases add an epoxide group across one of the four double

Although cardiac function appears normal in patients with cirrhosis at rest, cardiac function deteriorates in these patients under stress conditions. Decreased cardiac function against stress may be due to coronary microvascular dysfunction in these patients. In this study, we aimed to evaluate coronary microvascular dysfunction in patients with cirrhosis by measuring coronary flow reserve (CFR) by transthoracic echocardiography. Materials and methods. Thirty-eight patients with cirrhosis and 32 healthy subjects (as control group) were examined. In addition to standard two-dimesional (2D) and Doppler echocardiography, coronary flow velocity was measured by pulsed-wave Doppler from the middle to the distal part of the left anterior descending artery at the beginning and after dipyridamole infusion in the hyperemic state. CFR was measured as the ratio of hyperemic peak diastolic flow rate to basal peak diastolic flow rate. Results. CFR was significantly lower in the cirrhosis group than in the control group (2.01 ± 0.31 and 2.84 ± 0.62; p < 0.0001). Increasing age, increasing myocardial mass, high aspartate aminotransferase and alanine aminotransferase, low hemoglobin, high C-reactive protein, decreased cholesterol and platelet levels were found to be associated with the reduction in CFR. Among all these factors only, the hemoglobin level and age were independent determinants of impaired CFR. Conclusions. Impaired CFR in patients with cirrhosis promotes coronary microvascular dysfunction. The coronary microvascular dysfunction can potentially contribute to the development of cirrhotic cardiomyopathy.

Rheumatoid arthritis (RA) may promote endothelial dysfunction. This phenomenon requires further investigation, especially in collagen-induced arthritis (CIA), as it is considered the experimental model most similar to RA. identify CIA-induced changes in NE and ACh responses in mice aortas that may suggest endothelial dysfunction in these animals. Moreover, characterize CIA-induced modifications in iNOS expression in the aortas and cardiac and renal tissues taken from these mice that may be related to possible endothelial dysfunction. Male DBA/1J mice were immunized with 100 μg of emulsified bovine collagen type II (CII) plus complete Freund&#39;s adjuvant. Twenty-one days later, these animals received a boost of an additional 100 μg plus incomplete Freund&#39;s adjuvant. Fifteen days after the onset of the disease, aortic rings from CIA and control mice were challenged with NE and ACh in an organ bath. In these animals, iNOS was detected through immunohistochemical analysis of aorta...

Previous studies evaluating the progression of the necrotic wave in relation to heart rate were carried out only in animal models of ST-elevated myocardial infarction (STEMI). Aim of the study was to investigate changes of myocardial salvage in relation to different heart rates at hospital admission in timely reperfused patients with STEMI by using cardiovascular magnetic resonance (CMR). One hundred-eighty-seven patients with STEMI successfully and timely treated with primary coronary angioplasty underwent CMR five days after hospital admission. According to the heart rate at presentation, patients were subcategorized into 5 quintiles: &lt;55 bpm (group I, n = 44), 55-64 bpm (group II, n = 35), 65-74 bpm (group III, n = 35), 75-84 bpm (group IV, n = 37), ≥85 bpm (group V, n = 36). Area at risk, infarct size, microvascular obstruction (MVO) and myocardium salvaged index (MSI) were assessed by CMR using standard sequences. Lower heart rates at presentation were associated with a bigg...

Previous studies have shown that prodromal angina (PA) occurs frequently in acute myocardial infarction (MI) patients. However, the potential benefits of PA on ischaemic myocardial damage remain unknown. One-hundred and fifty-four patients with acute ST-segment elevation MI successfully treated with primary percutaneous coronary intervention (PPCI) were prospectively evaluated for new-onset PA in the week preceding infarction and other factors known to influence myocardial salvage. Cardiovascular magnetic resonance was performed 8 ± 3 days after MI for the assessment of area-at-risk (AAR), MI size, myocardial haemorrhage (MH), microvascular obstruction (MO), and myocardial salvage index (MSI). Patients with PA (n = 60) compared with those without PA (n = 94) showed similar AAR but significantly smaller MI size leading to larger MSI (0.53 ± 0.27 vs. 0.32 ± 0.26, P &lt; 0.001). Additionally, patients with PA had lower incidence of MH (18 vs. 33%) and MO (22 vs. 46%) than non-PA patien...

This paper examines the evidence for contrast echocardiography, both for improving assessment of left ventricular structure and function compared with unenhanced echocardiography and for the identification of myocardial perfusion. Based on the evidence, recommendations are proposed for the clinical use of contrast echocardiography.

Microvascular damage (MD) occurring soon after primary percutaneous coronary intervention (PPCI) may reverse or remain sustained within the first week after ST-elevation myocardial infarction (STEMI). We investigated the incidence, determinants, and long-term clinical relevance of MD reversal after PPCI.

Background: Rest thallium-201 (2~ myocardial perfusion imaging has been widely used for evaluation of myocardial ischemia/viability after myocardial infarction, but the ideal timing for imaging after injection to maximally estimate viability is not well established. Methods: Thirty-six patients with myocardial infarction underwent the initial, 3 h, and 24 h redistribution imaging after intravenous injection of 148-185 MBq 2~ The initial and 3 h images, the initial and 24 h images, and the 3 and 24 h images were compared double-blinded. Results: Out of the 184 abnormal segments based on the initial imaging, 56 (30%) segments improved by at least 1 grade on the 3 h imaging while 78 (42%) segments improved by at least 1 grade on the 24 h imaging. The 24 h late imaging detected more viable myocardium than the 3 h imaging did, with a significant difference (Z2= 5.680, p = 0.017). There were 158 abnormal segments on the 3 h imaging, with average 28% (44) segments improved by at least 1 grade on the 24 h imaging. There were 128 initial abnormal segments with no improvement on the 3 h imaging. Out of these segments, the 24 h late redistribution imaging detected additional redistribution in 26 segments, taking up 20%. Conclusions: Twenty-four hour late 2~ imaging will demonstrated additional redistribution in patients who have incompletely reversible defects on early redistribution imaging at 3h.

Background: Antihypertensive drugs are life-saving, but rapid or excessive blood pressure (BP) reduction can paradoxically cause acute organ ischemia, especially in patients with unrecognized arterial stenosis. The underlying biophysical mechanism is not fully described by traditional clinical models. Objective: To construct a hybrid biophysical model that links systemic BP reduction, focal arterial stenosis, and the shifted lower limit of autoregulation, and to derive a clinically usable predictive tool for perfusion collapse. Methods: A one-dimensional hemodynamic model was developed combining (i) Hagen-Poiseuille resistances in series (large artery, small artery, stenosis), (ii) quadratic pressure loss across stenosis , and (iii) a variable autoregulation threshold (right-shifted in chronic hypertension to 85 mmHg). Three scenarios were simulated: pre-treatment (mean arterial pressure MAP = 110 mmHg), gradual safe reduction (95 mmHg), and rapid aggressive reduction (65 mmHg). Nonlinear sensitivity analysis and non-dimensional reformulation were performed. Results: Total vascular resistance was Pa•s/m³. Post-stenotic perfusion pressures were 75, 70, and 53 mmHg respectively. The derivative showed a sharp peak of 1.3 at MAP ≈ 74 mmHg, confirming phase-transition-like behavior. A predictive clinical equation was derived:. Non-dimensional analysis identified a single governing parameter that controls the nonlinear collapse. Validation against published experimental data (Young & Tsai 1973) showed an average error of 2.5%. Conclusion: Rapid BP lowering can induce a nonlinear, threshold-dependent collapse of organ perfusion. Treatment should be individualized based on downstream perfusion constraints, not only on systemic BP values. The derived equation offers a mechanistic, bedside-usable rule.

This study evaluated the role of metabolic (cardiopulmonary gas exchange) exercise testing in differentiating physiologic LVH in athletes from HCM. BACKGROUND Regular intensive training may cause mild increases in left ventricular wall thickness (LVWT). Although the degree of left ventricular hypertrophy (LVH) is typically less than that seen in hypertrophic cardiomyopathy (HCM), genetic studies have shown that a substantial minority of patients with HCM have an LVWT in the same range. The differentiation of physiologic and pathologic LVH in this "gray zone" can be problematic using echocardiography and electrocardiography alone. Eight athletic men with genetically proven HCM and mild LVH (13.9 Ϯ 1.1 mm) and eight elite male athletes matched for age, size and LVWT (13.4 Ϯ 0.9 mm) underwent symptom limited metabolic exercise stress testing. Peak oxygen consumption (pVO 2 ), anaerobic threshold, oxygen pulse and respiratory exchange ratios were measured in both groups and compared with those observed in 12 elite and 12 recreational age-and size-matched athletes without LVH. Elite athletes with LVH had significantly greater pVO 2 (66.2 Ϯ 4.1 ml/kg/min vs. 34.3 Ϯ 4.1 ml/kg/min; p Ͻ 0.0001), anaerobic threshold (61.6 Ϯ 1.8% of the predicted maximum VO 2 vs. 41.4 Ϯ 4.9% of the predicted maximum VO 2 ; p Ͻ 0.001) and oxygen pulse (27.1 Ϯ 3.2 ml/beat vs. 14.3 Ϯ 1.8 ml/beat; p Ͻ 0.0001) than individuals with HCM. A pVO 2 Ͼ50 ml/kg/min or Ͼ20% above the predicted maximum VO 2 differentiated athlete's heart from HCM. CONCLUSIONS Metabolic exercise testing facilitates the differentiation between physiologic LVH and HCM in individuals in the "gray zone." (

Double orifice tricuspid or mitral valve formation has been explained as an imperfect formation of the atrioventricular valve leaflets by the endocardial cushion growth and fusion, thus explaining the frequent association with partial or complete atrioventricular canal [4, 5]. Nevertheless, both mitral and tricuspid variants can also occur not in association with atrioventricular canal [6]. Usually, if not associated with other cardiac malformations, they are considered benign with no important hemodynamic consequences. To the best of our knowledge this is the first case of double orifice tricuspid valve that has been reported in association with tetralogy of Fallot. On the other hand, tricuspid valve anomalies other than atrioventricular canal, such as straddling tricuspid valve, Ebstein's malformation, accessory leaflet or leaflets prolapse, have been described, although infrequently, in association with tetralogy of Fallot [7, 8]; nevertheless they had negligible technical impact on the surgical correction of tetralogy of Fallot. In the patient we reported, the tricuspid anomaly described had a fundamental impact on the surgical strategy, not enabling us to approach the ventricular septal defect and the right ventricular outflow tract through the tricuspid valve. Such a rare occurring malformation associated with the coronary artery anomaly can seriously challenge tetralogy of Fallot complete repair. At the time of surgery we decided for palliation because of the small body size of the patient. In a larger baby, either a trans-atrial or a trans-ventricular approach may be planned. If a larger tricuspid orifice is found, the ventricular septal defect can be patched through the right atrium and the infundibulum can be enlarged from inside. In this case, to achieve a fair visualization, a partial detachment of the tricuspid valve anterior and septal leaflets from the annulus should be done. However, if the infundibular obstruction appears to be severe, a right ventriculotomy, just below the level of the anom-alous anterior descending coronary artery, may be done, closing the ventricular septal defect through it and relieving the infundibular obstruction by positioning a right ventricle to pulmonary artery conduit as an accessory outlet.

Eleven patients with anterior myocardial infarction less than six hours old underwent intraaortic balloon pumping (IABP) in an attempt to control injury. Direct hemodynamic measurements excluded shock. Response to therapy was judged individually by comparison to a one-hour pretreatment period. There was no parallel control group. Five patients responded with an 84% fall in ST elevation in one hour, with preservation of precordial R waves and good ventricular function. In contrast, six patients responded poorly, with a 40% fall in ST elevation in one hour, Q wave develop- ment and poorer residual left ventricular function. Coronary angiography demonstrated a significant correlation between response and presence or absence of complete left anterior descending coronary artery occlusion. Early use of IABP in anterior myocardial infarction may interrupt injury, though in this series only in cases with residual left anterior descending patency.

Background Coronary flow reserve (CFR) and fractional flow reserve (FFR) provide complementary information on the coronary circulation. Using a pressure wire, it is possible to calculate CFR by thermodilution (CFR thermo ), so that FFR and CFR can be measured with a single guide wire. The present multicentric study was performed to compare the feasibility of CFR thermo obtained with an improved algorithm and a standardized injection technique and its agreement with Doppler-derived CFR (CFR Doppler ). In 86 patients with coronary artery disease recruited during 1 week in eight centres FFR, CFR thermo and CFR Doppler were measured. FFR could be obtained in all patients (100%). An optimal CFR Doppler could be obtained in 69% of the patients. CFR thermo could be obtained in 97% of the patients. A significant correlation was found between CFR Doppler and CFR thermo (r=0.79, P<0.0001) but CFR thermo tended to be higher than CFR Doppler . Conclusions In a setting close to 'real world' practice, this multicentric study confirms the feasibility and reliability of thermodilution-derived CFR. In addition, the safety and the swiftness of assessing FFR and CFR with one single guide wire makes the latter a unique clinical tool for the evaluation of the coronary circulation.

Background Coronary flow reserve (CFR) and fractional flow reserve (FFR) provide complementary information on the coronary circulation. Using a pressure wire, it is possible to calculate CFR by thermodilution (CFR thermo ), so that FFR and CFR can be measured with a single guide wire. The present multicentric study was performed to compare the feasibility of CFR thermo obtained with an improved algorithm and a standardized injection technique and its agreement with Doppler-derived CFR (CFR Doppler ). In 86 patients with coronary artery disease recruited during 1 week in eight centres FFR, CFR thermo and CFR Doppler were measured. FFR could be obtained in all patients (100%). An optimal CFR Doppler could be obtained in 69% of the patients. CFR thermo could be obtained in 97% of the patients. A significant correlation was found between CFR Doppler and CFR thermo (r=0.79, P<0.0001) but CFR thermo tended to be higher than CFR Doppler . Conclusions In a setting close to 'real world' practice, this multicentric study confirms the feasibility and reliability of thermodilution-derived CFR. In addition, the safety and the swiftness of assessing FFR and CFR with one single guide wire makes the latter a unique clinical tool for the evaluation of the coronary circulation.

This research was intended to determine the feasibility of tissue magnetic resonance (MR) imaging in comparison with tissue Doppler imaging and its potential implications for the estimation of filling pressure, in comparison with invasive measurement. BACKGROUND Evaluation of diastolic function using MR imaging is commonly confined to the study of transmitral flow. However, transmitral flow is unreliable for the estimation of left ventricular (LV) filling pressures in hypertrophy and normal systolic function. Normalizing early mitral velocity (E) for the influence of myocardial relaxation by combining E with early diastolic mitral septal tissue velocity (Ea) provides better Doppler estimates of filling pressures. Eighteen patients with hypertensive heart disease (LV mass index: 114 Ϯ 21 g/m 2 ), absence of valvular regurgitation, and with normal or mildly reduced systolic function (LV ejection fraction: 57.6 Ϯ 6.5%) referred for cardiac catheterization, underwent consecutive measurement of mitral flow and septal tissue velocities with phase-contrast MR and Doppler. These data were compared with mean pulmonary capillary wedge pressure (PCWP). There was a strong relation between MR (11.6 Ϯ 4.3) and Doppler-assessed (12.1 Ϯ 3.5) E/Ea (95% confidence interval of Ϫ1.5 to 0.5) (r ϭ 0.89, p Ͻ 0.0001). In addition, E/Ea related strongly to invasively measured PCWP (MR: r ϭ 0.80, p Ͻ 0.0001 and Doppler: r ϭ 0.85, p Ͻ 0.0001). CONCLUSIONS Tissue MR imaging is a feasible method to assess Ea. Combining E and Ea allowed similar estimation of filling pressure by MR and Doppler, in good agreement with invasive measurement. The potential confounding effect of valvular regurgitation needs further study. (

This study sought to assess myocardial perfusion and tissue oxygenation during vasodilator stress in patients with overt hypertrophic cardiomyopathy (HCM), as well as in HCM mutation carriers without left ventricular (LV) hypertrophy, and to compare findings to those in athletes with comparable hypertrophy and normal controls. Myocardial perfusion under vasodilator stress is impaired in patients with HCM. Whether this is associated with impaired myocardial oxygenation and tissue ischemia is unknown. Furthermore, it is not known whether perfusion and oxygenation are impaired in HCM mutation carriers without left ventricular hypertrophy (LVH). A total of 27 patients with overt HCM, 10 HCM mutation carriers without LVH, 11 athletes, and 20 healthy controls underwent cardiovascular magnetic resonance (CMR) scanning at 3-T. Myocardial function, perfusion (perfusion reserve index [MPRI]), and oxygenation (blood-oxygen level dependent signal intensity [SI] change) under adenosine stress were assessed. MPRI was significantly reduced in HCM (1.3 Ϯ 0.1) compared to controls (1.8 Ϯ 0.1, p Ͻ 0.001) and athletes (2.0 Ϯ 0.1, p Ͻ 0.001), but remained normal in HCM mutation carriers without LVH (1.7 Ϯ 0.1; p ϭ 0.61 vs. controls, p ϭ 0.02 vs. overt HCM). Oxygenation response was attenuated in overt HCM (SI change 6.9 Ϯ 1.4%) compared to controls (18.9 Ϯ 1.4%, p Ͻ 0.0001) and athletes (18.7 Ϯ 2.0%, p Ͻ 0.001). Interestingly, HCM mutation carriers without LVH also showed an impaired oxygenation response to adenosine (10.4 Ϯ 2.0%; p ϭ 0.001 vs. controls, p ϭ 0.16 vs. overt HCM, p ϭ 0.003 vs. athletes). In overt HCM, both perfusion and oxygenation are impaired during vasodilator stress. However, in HCM mutation carriers without LVH, only oxygenation is impaired. In athletes, stress perfusion and oxygenation are normal. CMR assessment of myocardial oxygenation has the potential to become a novel risk factor in HCM.

We describe a patient who presented transient ST-segment elevation and typical chest pain during an ischemia test with dipyridamole and technetium-tetrofosmin. Chest pain and electrical alterations disappeared promptly with sublingual nitroglycerin. Coronary angiography showed no epicardial lesions, and coronary vasospasm was suspected. We discuss possible explanations for this complication.

Presentamos el caso de una paciente que presentó elevación del segmento ST con angina y alteraciones en la perfusión isotópica durante una prueba de detección de isquemia con tomografía computarizada por emisión de fotones simples con tecnecio-tetrofosmín y dipiridamol como agente inductor de isquemia. El cuadro clínico y las alteraciones eléctricas cedieron en pocos minutos con la administración de nitroglicerina sublingual. La coronariografía posterior no mostró lesiones coronarias, por lo que el cuadro se interpretó como probable vasospasmo. Se discuten los posibles mecanismos explicativos.

Aim Experimental animal studies suggest that the use of skeletal myoblast in patients with myocardial infarction may result in improved cardiac function. The aim of the study was to assess the feasibility and safety of this therapy in patients with myocardial infarction. Twelve patients with old myocardial infarction and ischaemic coronary artery disease underwent treatment with coronary artery bypass surgery and intramyocardial injection of autologous skeletal myoblasts obtained from a muscle biopsy of vastus lateralis and cultured with autologous serum for 3 weeks. Global and regional cardiac function was assessed by 2D and ABD echocardiogram. 18 F-FDG and 13 N-ammonia PET studies were used to determine perfusion and viability. Left ventricular ejection fraction (LVEF) improved from 35.5±2.3% before surgery to 53.5±4.98% at 3 months (P=0.002). Echocardiography revealed a marked improvement in regional contractility in those cardiac segments treated with skeletal myoblast (wall motion score index 2.64±0.13 at baseline vs 1.64±0.16 at 3 months P=0.0001). Quantitative 18 F-FDG PET studies showed a significant (P=0.012) increased in cardiac viability in the infarct zone 3 months after surgery. No statistically significant differences were found in 13 N-ammonia PET studies. Skeletal myoblast implant was not associated with an increase in adverse events. No cardiac arrhythmias were detected during early follow-up. Conclusions In patients with old myocardial infarction, treatment with skeletal myoblast in conjunction with coronary artery bypass is safe and feasible and is associated with an increased global and regional left ventricular function,

Thrombus aspiration (TA) has been shown to improve microvascular perfusion during primary percutaneous coronary intervention (PCI) for patients with ST-segment elevation myocardial infarction (STEMI). The objective of our study was to assess the relationship between TA and myocardial edema, myocardial hemorrhage, microvascular obstruction (MVO) and left ventricular remodeling in STEMI patients using cardiovascular magnetic resonance (CMR). Sixty patients were enrolled post primary PCI and underwent CMR on a 1.5 T scanner at 48 hours and 6 months. Patients were retrospectively stratified into 2 groups: those that received TA (35 patients) versus that did not receive thrombus aspiration (NTA) (25 patients). Myocardial edema and myocardial hemorrhage were assessed by T2 and T2* quantification respectively. MVO was assessed via a contrast-enhanced T1-weighted inversion recovery gradient-echo sequence. At 48 hours, infarct segment T2 (NTA 57.9 ms vs. TA 52.1 ms, p = 0.022) was lower in t...

Background Tobacco smoking is the leading preventable cause of cardiovascular disease (CVD) globally, yet robust clinical data quantifying tobacco-attributable risk in North African populations, particularly Algeria, are exceedingly sparse. Objectives This study sought to estimate the independent association between active tobacco use and three major atherosclerotic outcomes-ischemic heart disease (IHD), stroke, and peripheral artery disease (AOMI)-in a large, unselected cardiology referral cohort from eastern Algeria. Methods The authors conducted a cross-sectional analysis of 10,791 consecutive patients (mean age 56.6 ± 19.3 years; 54.8% female) registered at the Khenchela Cardiology Center between June 2017 and April 2026. Active smoking status and clinical outcomes (IHD, stroke, AOMI) were ascertained algorithmically from structured electronic health records using validated keyword extraction. Multivariable logistic regression models were fitted to estimate adjusted odds ratios (aOR) with 95% confidence intervals (CI), controlling for age, hypertension, and diabetes mellitus. Results Active tobacco use was documented in 7.6% of the cohort (n=817). Smokers were predominantly male (96.2%) and significantly younger than non-smokers (median 50 vs. 59 years; P<0.001). In fully adjusted models, active smoking was independently associated with substantially increased odds of IHD (aOR: 2.60; 95% CI: 2.06-3.28; P<0.001), stroke (aOR: 1.80; 95% CI: 1.26-2.57; P=0.001), and AOMI (aOR: 7.96; 95% CI: 3.94-16.08; P<0.001). Notably, the crude null association between smoking and stroke (OR: 1.02; P=0.999) was reversed after adjustment for negative confounding by age and hypertension. Conclusions In this large cardiology cohort from eastern Algeria, active tobacco use conferred an 8-fold independent risk of peripheral artery disease and a 2.6-fold risk of ischemic heart disease. The unmasking of a significant stroke association after adjustment underscores the critical importance of accounting for demographic confounding in populations where smoking is concentrated among younger males. These findings provide urgent, locally relevant evidence to support the integration of structured tobacco cessation programs into Algeria's national cardiovascular prevention strategy.

Collateral channel opening is one of the components of the ischemic tolerance developing during subsequent coronary balloon occlusions. The effect of diabetes mellitus (DM) on coronary collateral recruitment (CR) is still not known. We therefore sought the effect of DM on CR in patients with stable angina pectoris (SAP) by using intracoronary pressure measurement technique. Study material consisted of 44 patients (21 diabetic) with SAP. All of the patients had single vessel disease with more than 70% vessel narrowing and all of them underwent stent implantation to this vessel. After angiography, fiber-optic pressure monitoring guidewire was advanced distal to the stenosis to be dilated. Myocardial fractional flow reserve (FFRmyo) was determined under adenosine hyperemia by the ratio of simultaneously measured mean distal pressure to mean aortic pressure. During subsequent two 1 minute balloon occlusions, distal pressures were recorded as coronary wedge pressure (CWP). Collateral flo...

Assessment of microvascular function after reperfused acute myocardial infarction (AMI) provides important insights for myocardial reperfusion and facilitates prediction of long-term left ventricular (LV) function and clinical outcome. In this study, we examined microvascular integrity 48 h after successful primary percutaneous coronary intervention (PCI) and compared predictive accuracy of the intracoronary pressure-wire-and transthoracic Doppler echocardiography-based parameters in the estimation of long-term LV infarct size and function.

In our pilot trial, the administration of low-dose intracoronary streptokinase immediately after primary PCI improved myocardial reperfusion but not long-term left ventricular size or function. These findings require clarification in a larger trial. (ClinicalTrials.gov number, NCT00302419.

During acute occlusion of an epicardial vessel collaterals preserve the microvascular perfusion and limit the extent of myocardial damage. Pressure-derived collateral flow index (CFIp) assessed by intracoronary pressure measurement allow us to quantify collateral vessel development. The angiographic myocardial blush (MB) scores, based on the contrast dye density and washout in the infarcted myocardium, provide important information about microvascular perfusion after acute myocardial infarction (AMI). In this study we assessed the microvascular perfusion with MB and studied the relation between CFIp in patients with AMI who treated with thrombolytic therapy and TIMI grade III flow restored in the infarct related artery (IRA). Forty-one patients with AMI who were treated with thrombolytic therapy and underwent stent implantation (mean of 3 days after AMI) to the IRA were included in this study. After angiography, CFIp was calculated as the ratio of simultaneously measured coronary wedge pressure -central venous pressure (Pv) to mean aortic pressure -Pv. Myocardial blush was graded densitometrically based on visual assessment of the relative contrast opacification of the myocardial territory subtended by the infarct vessel. There was a statistically significant correlation between CFIp and post-stent myocardial blush grades (P < 0.01, r = 0.70). There was a significant difference in mean CFIp among myocardial blush grades implying that higher CFIp is associated with better MB (0.39 ± 0.11 in grade 3, 0.32 ± 0.10 in grade 2, 0.24 ± 0.09 in grade 1, and 0.16 ± 0.08 in grade 0, P < 0.01). Well developed collaterals can limit microvascular damage by preserving microvascular perfusion. A higher pressure-derived collateral flow index is associated with better tissue level perfusion as evidenced by the higher myocardial blush score. (

Purpose Attempts to estimate coronary flow reserve (CFR) with single photon emission computed tomography (SPECT) tracers have been recently made. We compared two different methods for the estimation of CFR by SPECT imaging. Methods Fourteen patients with coronary artery disease underwent dipyridamole 99m Tc-sestamibi SPECT and intracoronary Doppler within 5 days. Myocardial blood flow (MBF) was estimated by measurement of first transit counts in the right pulmonary artery (PA) and left ventricular (LV) chamber, and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress MBF to rest MBF. Results Rest and stress MBF obtained using first transit counts from PA were higher compared to that from LV chamber (rest: 1.05±0.38 vs 0.87±0.34 counts/pixel per s, respectively, p<0.01 and stress: 1.34±0.45 vs 0.91±0.20 counts/pixel per s, respectively, p<0.05). In the study vessels, CFR by Doppler was 1.39±0.42, and SPECT CFR obtained using first transit counts from PA and LV chamber were 1.36±0.43 and 1.16±0.39, respectively (p across categories NS). A significant relationship between SPECT CFR obtained using first transit counts from PA and CFR by Doppler was found (r= 0.85, p <0.001). No relationship between SPECT CFR obtained using first transit counts from LV chamber and CFR by intracoronary Doppler was observed (r=0.43, p = NS). Conclusion SPECT-estimated CFR obtained using first transit counts from right PA is more accurate and correlates better with the results of intracoronary Doppler than estimated CFR obtained using arterial input function from LV chamber.

A three-dimensional computer model of human aortic arch with three branches is reproduced to study the pulsatile blood flow with Finite Element Method. In specific, the focus is on variation of wall shear stress, which plays an important role in the localization and development of atherosclerotic plaques. Pulsatile pressure pulse is used as boundary condition to avoid flow entry development, and the aorta walls are considered rigid. The aorta model along with boundary conditions is altered to study the effect of hypotension and hypertension. The results illustrated low and fluctuating shear stress at outer and inner wall of aortic arch, proximal wall of branches, and entry region. Despite the simplification of aorta model, rigid walls and other assumptions results displayed that hypertension causes lowered local wall shear stresses. It is the sign of an increased risk of atherosclerosis. The assessment of hemodynamics shows that under the flow regimes of hypotension and hypertension, the risk of atherosclerosis localization in human aorta may increase.

A three-dimensional computer model of human aortic arch with three branches is reproduced to study the pulsatile blood flow with Finite Element Method. In specific, the focus is on variation of wall shear stress, which plays an important role in the localization and development of atherosclerotic plaques. Pulsatile pressure pulse is used as boundary condition to avoid flow entry development, and the aorta walls are considered rigid. The aorta model along with boundary conditions is altered to study the effect of hypotension and hypertension. The results illustrated low and fluctuating shear stress at outer and inner wall of aortic arch, proximal wall of branches, and entry region. Despite the simplification of aorta model, rigid walls and other assumptions results displayed that hypertension causes lowered local wall shear stresses. It is the sign of an increased risk of atherosclerosis. The assessment of hemodynamics shows that under the flow regimes of hypotension and hypertension...