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Protective effect of collateral vessels during coronary angioplasty
M S Norell1, J P Lyons, J E Gardener
1Cardiac Department, London Chest Hospital.
Insights
Collateral vessels significantly reduce ischemia during angioplasty. Patients with collateral supply experienced less ST elevation and ejection fraction reduction, protecting heart muscle from damage.
Area of Science:
- Cardiology
- Interventional Cardiology
- Vascular Biology
Background:
- Coronary artery disease is a leading cause of mortality.
- Collateral circulation plays a vital role in myocardial perfusion.
- Understanding collateral function is crucial for managing ischemic events.
Purpose of the Study:
- To evaluate the protective effect of collateral vessels during left anterior descending coronary artery angioplasty.
- To quantify the impact of collateral supply on ischemic manifestations.
Main Methods:
- Studied 27 patients undergoing angioplasty of the left anterior descending coronary artery.
- Utilized intravenous digital subtraction left ventriculography to assess collateral vessels.
- Compared ischemic indicators (ST elevation, ejection fraction) between patients with and without collateral supply during balloon inflation.
Main Results:
- Patients with collateral vessels (group 2) showed significantly less ST segment elevation (0.9 mm vs. 4.9 mm) and reduced ejection fraction (12% vs. 24%) compared to those without (group 1).
- ST elevation and ejection fraction reduction correlated inversely with the extent of collateral supply (r = -0.680 and r = -0.446).
- Apical segment shortening reduction was less pronounced in patients with collateral supply.
Conclusions:
- Collateral circulation provides significant myocardial protection during acute coronary occlusion.
- Reduced ischemic manifestations suggest collateral vessels mitigate damage during angioplasty.
- The presence and extent of collateral supply are key determinants of myocardial resilience.
Abstract:
To assess the potential protective role of collateral vessels 27 patients undergoing angioplasty of the left anterior descending coronary artery were studied by intravenous digital subtraction left ventriculography. Fifteen patients had no collateral vessels (group 1) and 12 had some degree of collateral supply (group 2). During balloon inflation ST segment elevation in group 1 (4.9 mm) was significantly greater than that in group 2 (0.9 mm). Similarly the reduction in left ventricular ejection fraction was significantly greater in group 1 (24%) than in group 2 (12%). Both the size of ST segment elevation and the fall in ejection fraction correlated inversely with the extent of the collateral supply (r = -0.680 and r = -0.446 respectively). During balloon occlusion of the anterior descending coronary artery the percentage shortening of the anterior and apical segments fell in both groups but apical shortening fell to a lesser extent in group 2. An additional reduction in anterobasal contraction was confined to group 1. Electrocardiographic and ventriculographic manifestations of ischaemia produced by balloon inflation during angioplasty are less pronounced when collateral vessels are present. This suggests that the collateral circulation can protect myocardium at risk of ischaemia after coronary occlusion.