Obtuse Marginal Research Articles

The coronary arteries of the Garden dormouse ( Eliomys quercinus L., 1766)

The arrangement of the coronary arteries was studied in 18 Garden dormice (4 6@, 1499 ). Most of them (n=17) were examined using a corrosion-cast technique, while the remaining specimen was studied histologically. In the Garden dormouse the heart shows no interventricular grooves, and both the right and left coronary arteries become intramyocardial shortly after their origin from the aorta. The right coronary artery has two principal branches: the right circumflex branch and the dorsal interventricular branch. The conal branch also originates from the main trunk of the right coronary artery. The main branches of the left coronary artery are the left circumflex branch and one or two dorsal ventricular branches. When two dorsal ventricular branches exist, one of them often behaves as an obtuse marginal branch, running along the proximal half of the obtuse margin of the heart; thereafter the vessel turns towards the dorsal wall of the left ventricle. The ventral interventricular branch is sometimes absent. When present, it always rises from the left coronary artery and does not reach the apex of the heart. The ventricular septum is principally supplied by a well-developed septal artery arising from the left coronary artery; thus, the Garden dormouse exhibits a left septal pattern. A less important vascularization of the septum is established through thinner penetrating vessels originating from the right and left coronary arteries.

Intraoperative assessment of coronary artery bypass grafts using a pulsed doppler flowmeter

A pulsed Doppler flowmeter was used in a series of 352 consecutive patients undergoing isolated coronary artery bypass grafting. Doppler flow measurements were available on 909 single terminolateral bypass grafts (327 internal mammary arteries and 582 saphenous veins) and 58 sequential bypass grafts anastomosed to combinations of arteries. Flow (mL/min) categorized as a function of the recipient artery was distributed as follows: left anterior descending coronary artery, 69.9 ± 2.5; right coronary artery, 68.0 ± 5.0; diagonals, 61.0 ± 4.1; obtuse marginals, 55.9 ± 2.2; and posterior descending coronary artery, 53.3 ± 3.0 ( p < 0.001). Graft outflow obstruction resulting from torsion of the graft pedicle or anastomotic stricture was identified in 7 patients (2%). After graft revision, flow increased from 9 ± 4 mL/min to 69 ± 13 mL/min ( p = 0.023), and velocity rose from 4.6 ± 1.1 cm/s to 18.1 ± 2.4 cm/s ( p = 0.009). In conclusion, the system was adequate for operative use and allowed identification and correction of technical errors.

Use of the inferior epigastric artery for coronary bypass

Between December 1988 and April 1991, 74 free inferior epigastric arteries were used in 73 patients for coronary artery bypass grafts. In addition, 72 of the patients received a left internal mammary artery for single or sequential grafting to the left anterior descending system and 62 a right internal mammary artery to the circumflex or the right coronary artery. Twenty-seven patients had no saphenous vein available, and two had no suitable internal mammary artery; in an attempt to make a complete arterial revascularization, we chose the inferior epigastric artery as an alternative conduit in 24 young patients and in 10 reoperations; bilateral internal mammary artery dissection was avoided in four patients with impaired lung function and in six patients with selected two-vessel disease to spare one internal mammary artery. The technique for harvesting the inferior epigastric artery is described. Fifty-three inferior epigastric artery grafts were anastomosed to the distal right coronary artery or to its branches, 18 to the distal obtuse marginals of the circumflex artery (three as sequential grafts and one as a natural Y graft), and three to the left anterior descending system. The mean number of distal anastomoses is 3.60 per patient. Seventy proximal anastomoses of the inferior epigastric artery were made to the aorta and four to one internal mammary artery. There were four early deaths and one nonfatal myocardial infarction. Four abdominal wound hematomas needed surgical drainage. Sixty-one patients underwent angiographic study on postoperative day 10:59 of 61 inferior epigastric artery grafts (63 of 65 inferior epigastric artery distal anatomoses) and 111 of 111 internal mammary artery grafts (155 of 156 internal mammary artery distal anastomoses) were patent. Clinical follow-up of all the survivors (100% follow-up) could be obtained with a mean period of 9 months (1 to 28 months). There was no late cardiac death, no infarction, and all the patients were free of angina. Nineteen patients underwent a 6-month postoperative angiographic study. Seventeen of 19 inferior epigastric artery grafts were patent and 16 of 19 were intact; 34 of 34 internal mammary artery grafts (46 of 47 internal mammary artery distal anastomoses) were patent and intact. In conclusion, free inferior epigastric artery grafts can reach the diaphragmatic ischemic areas of the heart. The early patency rate and the clinical results are encouraging but only long-term evolution and evaluation can determine the true efficacy of the inferior epigastric artery graft as a reliable conduit for coronary artery bypass graft operations.

Endothelial modulation of the coronary vasculature in vessels perfused via mature collaterals.

Previous in vivo studies have shown that vasopressin, which releases the endothelium-derived relaxing factor and constricts coronary smooth muscle, produces augmented constriction of coronary microvessels perfused by mature collaterals. We hypothesized that chronic perfusion through collaterals produces endothelial dysfunction in the recipient vasculature. Mature collaterals were stimulated in mongrel dogs by the ameroid constrictor technique. After 3-6 months, rings of conduit vessels (obtuse marginals) were studied in organ chambers, and coronary microvessels (100-220 microns) were studied in a pressurized, no-flow state with a microvessel imaging apparatus. Eleven dogs were used as controls. Large vessels were preconstricted with prostaglandin F2 alpha to 30-70% of the maximum potassium chloride tension, and microvessels were preconstricted to 20-60% of the baseline diameter with the thromboxane mimetic U46619. Relaxations to the receptor-mediated agents acetylcholine and ADP were markedly impaired in collateral-dependent coronary microvessels, whereas relaxations to nitroglycerin were enhanced compared with microvessels from control dogs. Relaxation to the calcium ionophore A23187, which releases the endothelium-derived relaxing factor through nonreceptor-mediated mechanisms, were similar in control and ameroid microvessels. Constriction to vasopressin was augmented in collateral-dependent microvessels compared with controls. Responses to all agonists were similar between control and collateral-dependent large vascular rings. In conclusion, chronic perfusion through collateral vessels selectively impairs receptor-mediated endothelium-dependent relaxations and augments constriction to vasopressin in the coronary microcirculation. These findings may have important implications regarding neurohumoral regulation of perfusion to collateral-dependent myocardium.

Immediate Clinical Outcome of 600 Cases of Percutaneous Coronary Intervention (PCI)

This is an ongoing study done in National Institute of Cardiovascular Diseases (NICVD) during the period April 2002 to October 2007, few cases were done in Eurobangla Heart Hospital, Lab Aid Cardiac Hospital &amp; National Heart Foundation, SSMC &amp; MH, Metropolitan Medical Center. Total number of study population was 600 with male 550 &amp; female 50. Indication of Percutaneous coronary intervention (PCI) was- Unstable angina (with no prior myocardial infarction) 240 cases, MI inferior (with post Myocardial infarction angina) 204 cases &amp; MI anterior (with post MI angina) 156 cases. The risk factors were Hypertension (HTN) 310 cases (52%), smoking 426 cases (71%), Diabetes Mellitus (DM) 180 cases (30%), Positive family history for ischemic heart diseases (IHD) 120 cases (20%), Hyperlipidemia 150 cases (25%). Total number of target coronary arteries was 760 and total number of lesion was 803 of which780 lesions treated. Distribution of 803 lesions were left anterior descending coronary artery (LAD) 389 (proximal LAD 152, mid LAD 177, distal LAD 60), Right coronary artery (RCA) 230 (proximal 94, mid RCA 93, Distal RCA 26, RCA PD 17), Left circumflex coronary artery (LCX) 137 (proximal LCX 60, mid LCX 54, distal LCX 16, LCX PD 07), diagonal 15, obtuse marginal (OM) 20, ramus intermedius. Angiographic diagnosis of the patients were Single vessel disease 312 (52%), Double vessel disease 156 (26%) &amp; Triple vessel disease 132 (22%). Number of lesions treated were 803 of which 780 lesions was treated. PTCA with stenting done in 725 lesion &amp; 34 lesions treated with plain PTCA. Total occlusion was treated in 85 cases. The native vessel has a mean reference diameter was 3.03 ± 0.61 mm. Residual stenosis after deploying stents was &lt;10%. Our success rate was-angiographic success 96%, procedural success 94% &amp; clinical success 92%. Total mortality was 03. One patient having triple vessel disease died on P the procedure due to sudden cardiac arrest due to asystole, one pt died on the table due to acute closure by thrombus &amp; one patient died on 4th day due to huge retroperitoneal hemorrhage &amp; shock. Sub acute stent thrombosis occurs in 3 cases causing acute myocardial infarction &amp; one case required emergency CABG. Following procedure, in hospital course of the patients were uneventful. All the patients were discharged by three to fourth day of the procedure with improvement of their clinical condition. So the result of our study is good both in plain PTCA group &amp; PTCA + stent group. &#x0D; &#x0D; (University Heart Journal 2007; 3 : 50-56)