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Coronary collateral circulation
T J Pellinen1, K S Virtanen, L Toivonen
1First Department of Medicine, Helsinki University Central Hospital, Finland.
Insights
Coronary collateral circulation, vital for heart health, is more prevalent with greater artery obstruction. Collaterals improve left ventricular function and reduce myocardial infarction risk, but don't impact exercise test ST-segment response.
Area of Science:
- Cardiology
- Vascular Biology
- Clinical Investigation
Background:
- Coronary artery disease (CAD) involves atherosclerosis leading to arterial narrowing or occlusion.
- Coronary collateral circulation (CCC) represents an alternative blood supply pathway to the myocardium.
- The role of CCC in mitigating the effects of obstructive CAD is an area of ongoing research.
Purpose of the Study:
- To investigate the occurrence and influence of CCC in patients with angiographically confirmed CAD.
- To assess the impact of CCC on left ventricular (LV) contractility, myocardial infarction (MI) prevalence, and exercise tolerance.
Main Methods:
- A random sample of 286 patients with documented CAD was analyzed.
- Coronary angiography was used to assess coronary artery obstruction and collateralization.
- LV contractility, MI prevalence, and bicycle ergometer test results were evaluated in relation to CCC.
Main Results:
- CCC prevalence increased with the grade of coronary artery obstruction, most frequent in the right coronary artery (60%) and least in the left circumflex artery (21%).
- Intra-arterial collateral circulation was observed in 42% of cases.
- Presence of collaterals was associated with preserved LV contractility in cases of total left anterior descending artery occlusion and a lower prevalence of inferior MI with right coronary artery occlusion.
Conclusions:
- CCC is a significant compensatory mechanism in obstructive CAD, varying by artery.
- Collateralization can preserve LV function and reduce MI extent, particularly with right coronary artery occlusion.
- CCC did not significantly influence ST-segment response during exercise but improved peak work capacity in triple-vessel disease when not compromised.
Abstract:
The occurrence and influence of coronary collateral circulation and obstruction of the supplying coronary arteries on left ventricular contractility, prevalence of myocardial infarction, and bicycle exercise ergometer test were studied in a random sample of 286 patients with angiographically documented coronary artery disease. Collaterals appeared increasingly in all three main coronary arteries with grade of obstruction. The highest prevalence of collaterals occurred in stenosis of the right coronary artery (60%), followed by the left descending artery (45%); they occurred least in the left circumflex artery (21%) (p less than 0.001). The frequency of intra-arterial collateral circulation was 42%, 11%, and 12%, respectively (p less than 0.001). With total occlusion of the left anterior descending coronary artery, 22% of the patients had normokinetic anterior and apical left ventricular wall when collaterals were present. More often, the inferior wall showed normal contraction with total occlusion of the right coronary artery and collaterals [52%, p less than 0.001 compared with left anterior descending artery (LAD)]. The prevalence of inferior myocardial infarction was 39%, with collateral circulation to the totally occluded right coronary artery. The respective prevalence of anterior infarction and total occlusion in the left coronary artery was 58% (p less than 0.02). The presence or absence of collaterals had no obvious influence on ST-segment response during bicycle ergometer test. In triple-vessel disease, peak work capacity was better when collaterals to LAD were not jeopardized (427 kpm) than when jeopardized (321 kpm) (p less than 0.02).