Left Coronary Ostium Research Articles

EFFECTS OF N-(2-HYDROXYETHYL)NICOTINAMIDE NITRATE (SG-75) ON METHACHOLINE-INDUCED ECG CHANGES IN INTACT ANESTHETIZED RATS

The effects of a newly developed nicotinamide derivative, N-(2-hydroxyethyl)nicotinamide nitrate (SG-75, Nicorandil), were examined in an experimental model of angina pectoris, utilizing methacholine-induced ECG changes as main parameter in intact anesthetized rats. The right carotid artery was exposed and through it a special cannula was inserted to a point near the right and left coronary ostium. Such a device made it possible to inject drugs more selectively into the coronary artery. Single intra-aortic injections of 4 to 8 μg of methacholine caused a transient elevation of the ST segment and T wave of the electrocardiogram (ECG). SG-75 (3 mg/kg i.v. or 10 mg/kg p.o.) prevented these changes in the ECG, while a potent vasodilator, papaverine, failed to do so. In the isolated, donor-perfused rat heart, SG-75 (1-30 μg) injected into the coronary perfusion system caused dose-dependent vasodilation, while 0.1-0.8 μg acetylcholine as well as methacholine produced marked vasoconstriction. SG-75 (10 mg/kg) administered orally to the donor rat inhibited the coronary vasoconstriction produced by the cholinomimetic drugs, whereas papaverine (30 μg i.a.) failed to prevent it. The inhibitory effects of SG-75 on methacholine-induced ECG changes in intact rats seemed to be due to its spasmolytic action.

Coronary ostial stenosis following aortic valve replacement without continuous coronary perfusion

The development of coronary ostial stenosis following aortic valve replacement has been attributed to intraoperative trauma to the coronary vessels during continuous coronary perfusion. We describe two patients with this lesion in whom continuous coronary perfusion was not used during aortic valve replacement. Both patients were successfully treated with saphenous vein bypass grafting. Intraoperative observation of the aortic root at the time of the bypass operation in one case revealed the left coronary ostium to be pinpoint in size and involved in a dense fibrous reaction extending up from the sewing ring of the prosthesis. The findings in these cases support the hypothesis that coronary ostial stenosis following aortic valve replacement may be due to a fibrous reaction in the aortic root secondary to turbulent flow through the aortic prosthesis.

Congenital atresia of the left coronary ostium and hypoplasia of the left main coronary artery

The clinical and pathological findings are described in a six-month-old female with an unusual congenital malformation, atresia of the orifice and hypoplasia of the left main coronary artery. The literature is reviewed and the clinical findings are discussed. A comparison has been made with the anatomic findings in true single coronary artery and with the angiographic findings in anomalous origin of the left coronary artery from the main pulmonary artery.

Myocardial Infarction and Left Coronary Ostial Stenosis in Infancy Simulating Anomalous Origin of the Left Coronary Artery

A case of a 3-month-old male infant with myocardial infarction due to left coronary ostial stenosis is presented. Clinically it was quite similar to anomalous origin of the left coronary artery. Postmortem examination revealed quite narrow left coronary ostium and myocardial infarction with aneurysm of the left ventricular apex.

Congenital aortic valve anomaly: Aortic regurgitation with left coronary artery isolation

A case is reported of aortic regurgitation resulting from a congenitally abnormal aortic valve. The left coronary cusp of the valve was small and adhered to the aortic wall, so that there was insufficient valve tissue to maintain diastolic valve competence. In addition, this rudimentary cusp completely occluded the left coronary ostium. The patient was treated successfully by valve replacement.

Congenital Atresia of the Left Main Coronary Artery Ostium

Three patients with the rare anomaly of congenital absence of the ostium of the left main coronary artery are presented. In two of the patients, aged 50 and 52 respectively, the diagnosis was established during selective coronary cineangiography for a severe anginal syndrome. The third patient, a 16-year-old-girl, underwent cardiac catheterization for investigation of a congenital heart malformation, when a single right coronary artery was demonstrated with absence of the main coronary artery ostium. Two patients underwent successful aortocoronary bypass grafting. In view of the occurrence of sudden death and massive myocardial infarction in adult patients shown to have severe or complete obstruction of the left main coronary artery, it is suggested that adult patients with this condition, who require open-heart surgery for any other cardiac disorder, should undergo aortocoronary bypass grafting concurrently even prior to the development of anginal symptoms. Children shown to have this anomaly should be subjected to long-term follow-up and have an aortocoronary bypass graft performed when symptoms of coronary insufficiency develop.

Atresia of the left coronary artery ostium. Report of a case.

Atresia of the left coronary artery ostium. Report of a case.

The Effect Upon Coronary Blood Flow of Coronary Ostial Intubation with an Angiographic Catheter

Fifty-two patients undergoing cardiac catheterization were studied to determine whether intubation of the coronary ostium in the course of coronary angiographic studies interferes with coronary blood flow. Pressure at the tip of the catheter and coronary sinus blood flow were measured continuously during insertion of a No. 7.2 French Judkins' catheter into the left coronary ostium and during withdrawal of the catheter from it. In 48 of the 52 patients, there was no change in blood flow related to manipulation of the catheter. In four patients, either a drop in flow following insertion of the catheter or a rise following withdrawal or both were recorded. Two of these four patients had high-grade obstruction of the main left coronary artery, and in the other two the catheter inadvertently advanced and became wedged. In all four cases, reduction in coronary flow was indicated by a drop in or "ventricularization" of the catheter-tip pressure. It is concluded that in the large majority of instances, intubation of the coronary ostium during coronary angiographic studies causes no interference with resting coronary blood flow, but that monitoring of catheter-tip pressure is an important, as well as a valid, procedure for detecting such an interference if it should occur.

An extracorporeal shunt for the measurement of coronary flow in the closed-chest dog.

An extracorporeal shunt circuit interposed between the left carotid artery and the left coronary ostium employs an electromagnetic flowmeter to measure coronary blood flow in the closed-chest anesthetized dog. Flow may be measured with the animal's arterial pressure as the driving force; introduction of a roller pump, or a roller pump and a negative feedback pressure controller allows for constant flow or constant pressure modes. During occlusion of the circuit or cessation of pump flow, retrograde coronary blood flow can be collected for measurement. The construction of the circuit is relatively simple and inexpensive, using common laboratory materials and a commercially available electromagnetic flowmeter and probe.

Postperfusion coronary ostial stenosis: Incidence and significance

In a study of 117 consecutive aortic valve replacements in which selective coronary perfusion was routinely employed, four patients developed coronary ostial stenosis (3.5 per cent). Continuous selective coronary perfusion was performed by use of Mayo balloon catheters with individual measuring of pressure and flow. All 4 patients developed progressive symptoms of angina pectoris within 6 months of the original operation, after uneventful recoveries. All 4 were found to have lesions in the left main coronary ostium and required a coronary bypass. Two made uneventful recoveries and are presently asymptomatic, whereas 2 died in the immediate postoperative period. The literature indicates that the reported incidence of this complication varies from 1 to 5 per cent. Furthermore, the mortality rate for reoperation in these patients is higher than that for those undergoing uncomplicated coronary bypass without an antecedent procedure. Our experience confirms the lethal nature of this complication and the necessity for reoperation once the diagnosis is established. The development of these dangerous lesions must be taken into account in the prevailing controversy between the most effective methods of myocardial protection during aortic valve replacement.

Myocardial Revascularization

THE SURGICAL treatment of ischemic heart disease is not new. Omentopexy, epicardiectomy, poudrage, and various types of neurectomy or sympathectomy were introduced prior to World War II. Perhaps the most exotic procedure introduced in this early era was the internal mammary implant procedure proposed by Vineberg1of Montreal. Generally speaking, these surgical procedures intended for the coronary patient evoked limited enthusiasm from the profession at large. This initial era of revascularization surgery failed primarily because the diagnostic procedures of the time were inadequate, both for (1) proper case selection and (2) worthwhile assessment of the patient who did survive a given surgical procedure. The current era of revascularization surgery follows the introduction of selective coronary arteriography. In 1958, Sones and Shirey2demonstrated the feasibility of selective coronary arteriography by combining the image intensifier and catheter injection of both the right and the left coronary ostia. With refinement, Sones'

Myocardial revascularization. A 14-year overview of the Cleveland Clinic experience.

THE SURGICAL treatment of ischemic heart disease is not new. Omentopexy, epicardiectomy, poudrage, and various types of neurectomy or sympathectomy were introduced prior to World War II. Perhaps the most exotic procedure introduced in this early era was the internal mammary implant procedure proposed by Vineberg1of Montreal. Generally speaking, these surgical procedures intended for the coronary patient evoked limited enthusiasm from the profession at large. This initial era of revascularization surgery failed primarily because the diagnostic procedures of the time were inadequate, both for (1) proper case selection and (2) worthwhile assessment of the patient who did survive a given surgical procedure. The current era of revascularization surgery follows the introduction of selective coronary arteriography. In 1958, Sones and Shirey2demonstrated the feasibility of selective coronary arteriography by combining the image intensifier and catheter injection of both the right and the left coronary ostia. With refinement, Sones'

RELATIONSHIP BETWEEN HEART WEIGHT AND THE CROSS SECTIONAL AREA OF THE CORONARY OSTIA

Sex variation in the area of the coronary ostia was studied in hearts with a normal weight (heart weight less than 400 g) and hypertrophic hearts (heart weight greater than or equal to 400 g). Also studied was a possible sex difference in the correlation between heart weight and the area of the coronary ostia. The study was performed on 379 post mortem hearts. In the group of hearts with a normal weight the area of the left coronary ostium in both sexes was greater than the right but the difference was statistically insignificant. There was no sex difference in the area of the left coronary ostium, whereas the area of the right coronary ostium was statistically significantly less in women. In the group of hyperthopic hearts the left coronary ostium increased in area with increasing heart weight. The difference in the area of the left coronary ostium between hearts with normal weight and hypertrophic hearts was stastically significant in men, but not in women. The right coronary ostium showed minimal increase in size with increasing heart weight and the difference in both sexes between the two groups was statistically insignificant. In the group of hypertrophic hearts the heart weight was best correlated to the area of the left coronary ostium in both sexes, but the values did not reach statistically significance. On the basis of this study the area of the right coronary ostium appears to be a bottleneck with regard to an adequate blood supply to a hypertrophic myocardium.

Atresia of the proximal left coronary artery associated with supravalvular aortic stenosis: Surgical treatment

The case of a 9-year-old boy with symptomatic myocardial ischemia due to atresia of the left coronary ostium is discussed. A saphenous vein bypass graft was placed from the ascending aorta to the left anterior descending coronary artery. Symptoms have abated, the patient has normal exercise tolerance, and hemodynamic parameters have improved.

Atresia of the left coronary artery ostium. Repair by saphenous vein graft.

Symptoms and electrocardiographic changes of acute myocardial ischemia in a 10-year-old boy resulted from congenital atresia of the ostium of the left coronary artery. At 14 years of age persistence of symptoms and a positive exercise test prompted surgical treatment by aortocoronary artery saphenous vein bypass graft. Two months postoperatively, the symptoms and the abnormal findings on exercise test had subsided and forward flow through the graft to the left coronary artery was demonstrated by contrast angiography.

Fusion of the left aortic cusp to the aoic wall with occlusion of the left coronary ostium, and aortic stenosis and insufficiency.

The case of a 16-year-old girl with a unique anomaly of the coronary arterial tree is presented. This report concerns the first known case of isolated adherence of the left coronary aortic valve cusp to the aortic wall. This produced total obstruction of the left coronary artery ostium, angina pectoris, syncope, aortic stenosis, and aortic insufficiency. Freeing the adherent cusp from the aortic wall restored patency of the left coronary artery, relieved the aortic insufficiency, and resulted in disappearance of the angina pectoris and syncope. This case adds to the growing spectrum of nonatherosclerotic coronary abnormalities which are capable of producing myocardial ischemia.

Double-outlet left ventricle with an intact ventricular septum. Clinical and autopsy diagnosis and developmental implications.

Clinical, laboratory, and anatomic findings were presented concerning the first clinically diagnosed and autopsy proved case of origin of both great arteries from the morphologically left ventricle. The salient pathologic findings were: normally interrelated chambers (noninverted) in situs solitus; no ventricular septal defect; infundibular atresia; infundibulum related only to the right ventricle; absence of infundibular musculature beneath the great arteries, with aortic-mitral and pulmonary-mitral fibrous continuity; semilunar valves side by side, aortic to the right and pulmonary to the left, and at approximately the same height; thick-walled and small-chambered right ventricle with endocardial fibroelastosis of the apical half of the ventricle; hypertrophy and enlargement of both atria and of the left ventricle; absence of the left coronary ostium; and a fistula between the right ventricular apex and the anterior descending coronary artery. The main developmental implications of this rare case appear to be as follows: (1) strong support is given for the differential conal growth hypothesis concerning the morphogenesis of great arterial interrelationships; (2) truncus arteriosus communis would appear to have atresia, not absence, of the subpulmonary infundibulum; (3) the truncal septum does extend a short distance below the semilunar valves; and (4) the conus arteriosus appears to be a separate cardiac segment, not part of the right ventricle and not part of the great artelies.

Prosthetic replacement of the mitral or aortic valves: A preliminary report on 111 cases

Total replacement of the aortic or mitral valve with a ball and seat prosthesis was used in a consecutive series of 111 patients with a mortality rate of 13.5 per cent. In the first 22 operations, 7 deaths occurred (32%), whereas in the last 89 operations there were only 8 deaths (9%), indicating the improvement in surgical technic and management. The valves were inserted during temporary cardiopulmonary bypass under normothermic conditions, using 5% glucose in distilled water to prime the pump oxygenator, eliminating the need for fresh, heparinized blood. Ages of the patients ranged between 15 and 72 and 2 patients undergoing successful aortic valve replacement were more than 70 years of age. Embolic phenomena after operation occurred in 4 patients, 3 of whom had prosthetic mitral valves. One patient with an aortic replacement had thrombosis of the valve ring with occlusion of the left coronary ostium. Prophylactic anticoagulants were used in all recent mitral replacements, but not in aortic valve replacements. Surviving patients have been improved, and many are engaged in normal activity. At present, total valve replacement offers an effective means of treatment for advanced mitral and aortic valvular disease with a relatively low surgical risk.