Dilatation of Coronary Stenosis as the Salutary Effect of Nitroglycerin in Relief of Myocardial Ischemia in the Dog
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Summary: To clarify the role of coronary responses to nitroglycerin (NTG) in relieving myocardial ischemia, we examined the effects of NTG in canine models of dynamic and fixed coronary stenoses. Application of coronary stenosis in the proximal left circumflex artery decreased resting coronary blood flow by ×40% and caused a significant depression of left ventricular (LV) dP/dt. During fixed coronary stenosis created with an externally applied constrictor device, intravenous NTG, 5 μg/kg, reduced mean aortic pressure by 12 ± 1.1 mm Hg (mean ± SEM, p < 0.01) and coronary blood flow by 9 ± 1.0% (p < 0.01) but did not affect stenosis resistance and LV dP/dt. During dynamic coronary stenosis produced with an intraluminal microballoon occluder, intravenous NTG caused a marked increase in coronary blood flow by 40 ± 8.3% (p < 0.01) and a decrease in stenosis resistance by 62 ± 9.3% (p < 0.01), as compared with postocclusion values, concomitant with a significant improvement in LV dP/dt. Intracoronary infusion of NTG, 1.0 μg/kg/min, had few systemic and coronary hemodynamic effects during fixed coronary stenosis, whereas intracoronary NTG increased coronary blood flow and reduced stenosis resistance, depending on its dose, during dynamic coronary stenosis. These results indicate that NTG is capable of increasing coronary blood flow and alleviating myocardial ischemia due to direct stenosis-dilating effects related to the vasomobility of the coronary stenosis.Keywords:
Coronary circulation
Coronary arteries
Coronary vessel
Circumflex
The present study was conducted on coronary arteries of buffalo, horse, camel and dog. In camel the left coronary artery and its circumflex branch were well developed. The intermediate groove was also well developed and was occupied by branch of left coronary artery. In horse, intermediate groove was absent. The circumflex branch of left coronary artery was anastomosed with right circumflex branch. In dog and horse, the descending branches of right and left coronary arteries were not anastomosed, whereas in buffalo and camel these branches were joined with each other.
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Coronary artery anomalies (CAA) are congenital changes in their origin, course, and/or structure. Intercoronary communication (ICC) is a very rare subset with uni- or bidirectional blood flow between two or more coronary arteries. We present the case of a 58-year-old man with an acute coronary syndrome whose coronary angiography incidentally showed a surprising and very rare communication between the right coronary and left circumflex arteries.
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Coronary circulation
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128 human hearts including 70 males and 58 females in all age groups were used for the present study. Coronary arteries were dissected out from all the human hearts. The luminal diameter was studied in all the four major coronary arteries, namely, right coronary artery (RCA), left coronary artery (LCA), left anterior descending artery (LAD) and left circumflex coronary artery (LCX) in both the sexes. The histological sections were stained with H & E stain and the diameter was measured with the help of ocular micrometer. Among the four major coronary arteries luminal diameter is found to be more in LCA followed by LAD, RCA and LCX. Luminal diameter was found to be more in males as compared to females in all the four major coronary arteries. The data of present study can be useful for doing any instrumentation of coronary artery.
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A successful outcome after arterial switch operation (ASO) for transposition of the great arteries (TGA) depends in large part on the adequacy of transfer of the coronary arteries to the neoaorta. The present paper describes a new technique of coronary transfer which was used in 43 patients: 28 neonates with TGA and intact septum (with coarctation in one), 10 neonates with TGA and ventricular septal defect (with coarctation in one), 2 children undergoing ASO after failed Senning operation and 3 patients with complex TGA. A standardized uniform technique of coronary transfer was used; this technique involved reimplantation of the two coronary ostia side by side after excision of a single button of neoaortic wall. Most coronary patterns were encountered: the usual pattern in 30, circumflex from right coronary artery in 7, inverted coronary arteries in 3, inverted circumflex and right coronary arteries in 3. There was no early coronary-related mortality or morbidity. One late death (3 months) was probably coronary-related. The overall coronary risk was 2.3% (70% confidence limits = 0.3%-7.5%). The proposed technique of coronary transfer can be used in most patients with TGA (all patients without coronary arteries running between the great arteries) and entails a low coronary risk.
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Background— Coronary spasm plays an important role in the pathogenesis of ischemic heart disease. However, similarities and differences between coronary spasm and atherosclerosis are not known. We examined the angiographic characteristics of coronary spasm in comparison with those of atherosclerosis. Methods and Results— Thirty-two left anterior descending arteries, 11 left circumflex arteries, and 23 right coronary arteries with spasm and atherosclerotic plaque were analyzed for the localization of spasm in comparison with that of plaque in 47 patients (38 men and 9 women, mean age 66.8�10.3 yrs). Spasm predominantly occurred at the branch point as compared with plaque in each of the 3 arteries (76.7% versus 23.3%, P<0.0001; 72.7% versus 9.1%, P<0.039; and 60.0% versus 10.0%, P=0.002, in the left anterior descending, left circumflex, and right coronary arteries, respectively). Spasm involved the proximal segment less frequently as compared with plaque in each of the 3 arteries (56.7% versus 93.3%, P<0.00...
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Coronary arteries of anomalous origin are uncommon and all three coronary arteries arising from a single sinus of Valsalva is very rare. Percutaneous coronary intervention of such arteries is technically difficult and challenging. We report the case of a patient with all three coronary arteries arising from the right sinus of Valsalva who presented with acute coronary syndrome. Coronary angiography showed significant stenosis of the left circumflex and left anterior descending coronary arteries followed by successful angioplasty and stenting of these arteries.
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132 hearts obtained from cadavers were dissected in order to study anomalies in the course and branches of human coronary arteries. Only in 1 heart was a deviation of the circumflex branch of the left coronary artery taking a course inferior to the coronary sulcus observed. The right coronary artery travelled the entire length of the coronary sulcus on the back of the heart and gave both a posterior ventricular and a collateral branch. Circumflex branches of the right and left coronary arteries did not anastomose.
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Coronary spasm plays an important role in the pathogenesis of ischemic heart disease. However, similarities and differences between coronary spasm and atherosclerosis are not known. We examined the angiographic characteristics of coronary spasm in comparison with those of atherosclerosis.Thirty-two left anterior descending arteries, 11 left circumflex arteries, and 23 right coronary arteries with spasm and atherosclerotic plaque were analyzed for the localization of spasm in comparison with that of plaque in 47 patients (38 men and 9 women, mean age 66.8+/-10.3 yrs). Spasm predominantly occurred at the branch point as compared with plaque in each of the 3 arteries (76.7% versus 23.3%, P<0.0001; 72.7% versus 9.1%, P<0.039; and 60.0% versus 10.0%, P=0.002, in the left anterior descending, left circumflex, and right coronary arteries, respectively). Spasm involved the proximal segment less frequently as compared with plaque in each of the 3 arteries (56.7% versus 93.3%, P<0.0001; 18.2% versus 81.8%, P=0.016; and 15.0% versus 75.0%, P<0.0001 in the left anterior descending, left circumflex, and right coronary arteries, respectively). Most spasms occurred at the nonplaque site in each of the 3 arteries (73.3%, P=0.018; 100%, P<0.0001; and 75.0%, P=0.041 in the left anterior descending, left circumflex, and right coronary arteries, respectively).Coronary spasm preferentially occurred at branch points and nonplaque sites, whereas the atherosclerotic lesion was predominantly localized at the nonbranch points of the curved proximal segments. Coronary spasm may thus be a manifestation of a distinct type of arteriosclerosis different from the lipid-laden coronary atherosclerosis.
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