Study of Coronary Collaterals in Patients with Stable Angina

Background: Coronary collateral circulation is an alternative source of blood supply to the myocardium in coronary atherosclerotic disease. They provide adequate flow to the major epicardial branches of the coronary artery. Indicator of cardiac ischemia like stable angina pectoris may determine the presence of coronary collateral circulation. Methods and results: In this prospective observational cross sectional study, 150 patients with stable angina pectoris with or without MI (myocardial infarction) and or coronary intervention were enrolled. Presence of coronary collaterals in coronary angiogram was defined as Rentrop grade > 1. Patients were divided into two groups. Group A patients having Rentrop grade 0 and Group B patients are with collateral circulation, having Rentrop grade 1-3. Patients are compared in these groups. Total (63%) patients with stable angina were in Group B with coronary collateral circulation and only (37%) patients with stable angina pectoris were in Group A without collaterals. Conclusions: The incidence of development of coronary collaterals was significantly higher in patients with stable angina pectoris. January 2007 to December 2008. A total of 150 patients with stable angina pectoris with or without MI (myocardial infarction) and or coronary intervention were enrolled undergoing CAG and PCI were included in the study. Patients having normal coronary artery and or coronary artery lesion < 70% (in case of Left main artery < 50%) in angiogram were excluded from the study. Assessment of Coronary Angiographic findings Coronary angiogram was done by percutaneous femoral arterial catheterization. Cardiac catheterization was done in the Cardiac Catheterization Laboratories of Department of Cardiology, BSMMU. Six (6) standard angiographic views of left coronary artery were taken and three (3) standard views were taken for right coronary artery. Significant coronary artery disease (CAD) was analyzed in four major coronary arteries i.e. Left main if > 50% stenosis or other epicardial arteries (left anterior descending artery, left circumflex artery and right coronary artery) if > 70% stenosis. Lesions in diagonal and septal branch were considered under left anterior descending artery and lesions in ramus intermedius and obtuse marginal were considered under left circumflex artery. The presence of coronary collaterals on each base line coronary angiogram was defined and visually assessed with Rentrop’s classification (grade 0-3). Coronary collateral presence was defined as Rentrop’s grade > 1.8 Comparison Patients were divided into two groups. Group A patients having Rentrop grade 0 and Group B patients are with collateral circulation, having Rentrop grade 1-3. Patients having stable angina with or without MI, previous coronary interventions are compared in these groups. We tried to find out whether there is any correlation between stable angina pectoris and coronary collateral circulation. Statistical Analysis Statistical analysis was conducted using SPSS 11.5 for windows software. Categorical data were expressed as frequencies and corresponding percentages. Parametric data were expressed in mean ± SD. Parametric data were evaluated by independent sample “t” test and categorical data were evaluated by Chi-square test as needed. Level of significance for all analytical test were set at 0.05 and p value d”0.05 is considered significant. Results: As I mentioned before based on Rentrop grading the study subjects were divided into two groups. One is Group-A without collaterals (comprised of 55 patients) and GroupB with collaterals (consisted of 95 patients). Table I compares the risk factors between the groups. Of the 6 risk factors shown in the table hypertension was observed to be significantly higher in Group-A (77.3%) than that in Group-B (58.3%) (p = 0.033). The low physical activity was also significantly prevalent in the former group (84.1%) than that in the latter group (63.1%) (p = 0.040). The other risk factors like diabetes mellitus, dyslipidaemia, current smoker and family history CHD were almost identically distributed between groups (p > 0.05). Table-I Comparison of risk factors between two groups Risk factors Coronary collateral circulation pGroup-A Group-B value (n = 55) (n = 95) Diabetes mellitus 19(34.1%) 33(34.5%) 0.961 Hypertension 42(77.3%) 55(58.3%) 0.033 Dyslipidemia 14(25.2%) 25(26.2%) 0.884 Current smoker 21(38.6%) 49(51.8%) 0.157 Family history CHD 11(20.5%) 19(20.5%) 0.997 Low Physical activity 46(84.1%) 60(63.1%) 0.040 # Data were analysed using Chi-square (χ2) Test. * Figures in the parentheses denoted corresponding percentage. Table II shows that stable angina pectoris, angina pectoris on exertion, stable angina with previous myocardial infraction and previous PTCA or CABG were significantly higher in Group-B than those in Group-A (p < 0.001, p < 0.001, p < 0.001 and p = 0.048 respectively). The mean duration of AP (angina pectoris) until index CAG or PTCA was also staggeringly higher in Group-B than that in Group-A (40.8 ± 25.8 vs. 13.1 ± 17.4, p < 0.001). The mean duration since MI (myocardial infarction) until index CAG or PTCA was also much higher in the former group than that in the later group (39.6 ± 32.9 vs. 11.6 ± 23.0, p = 0.003). The incidence of multi vessel coronary disease was significantly higher in Group-B (66.7%) than that in GroupA (40.9%) (p = 0.005). Table II Distribution of components cardiac ischemic score between groups Components Coronary collateral circulation pGroup-A Group-B value (n = 55) (n = 95) Stable angina pectoris 55(37%) 95(63%) < 0.001 Angina pectoris on 42(77.3%) 90(94%) < 0.001 exertion Stable angina with 17(27.3%) 43(72%) < 0.001 previous myocardial infraction# Stable angina with 00 8(8.3%) 0.048 previous PTCA or CABG# Duration of AP until 13.1 ± 17.4 40.8 ± 25.8 < 0.001 index CAG or PTCA (months) * Duration since MI until 11.9 ± 23.0 39.6 ± 32.9 0.003 index CAG or PTCA (months) * Multi vessel coronary 22(40.9%) 63(66.7%) 0.005 disease# # Data were analysed using c2 Test; Figures in the parentheses denote corresponding %. * Data were analysed using Student’s t-Test and were presented as Mean ± SD. Total (63%) of the patients with stable angina exhibiting presence of coronary collaterals (Group-B), 8% had experience of past coronary intervention, 12.2% noncardiac surgery and 4.8% transient ischemic attack (TIA). In Group-A 37% with stable angina showed 13.6% had past history of non-cardiac surgery. The presence of stable angina pectoris was significantly higher in patients with coronary collaterals than that in patients without coronary collaterals (p < 0.001) (Table III). University Heart Journal Vol. 6, No. 2, July 2010