Coronary collateral function during exercise.

Abstract

SUMMARY A totally occluded coronary vessel subtending a noninfarcted, entirely collateral-dependent myocardial region (NIECDMR) provides an opportunity to assess collateral perfusion during exercise stress. Collateral function was determined by analysis of exercise thallium-201 myocardial perfusion images from 31 patients who had at least one NIECDMR (total 41 NIECDMRs) documented during catheterization. Twenty-two of 41 NIECDMRs manifested exercise-induced perfusion defects and 19 were normally perfused. The exercise-negative NIECDMRs were further categorized: Group 1 NIECDMRs (n = 13) were associated with defects in other myocardial regions supplied by diseased vessels and were considered negative relative to other jeopardized regions; group 2 NIECDMRs (n = 6) were not associated with exercise-induced defects in other myocardial regions, which suggests that collateral perfusion was adequate during maximal exercise. Regions supplied by a diseased left anterior descending coronary artery manifested exercise defects regardless of collaterals, possibly because these regions were larger and required more perfusion. Angiographic indexes of collateral function did not clearly predict exercise results.THE FUNCTIONAL ROLE of human coronary collaterals has been the subject of intense interest since their recognition in pathologic studies and coronary arteriography.' Coronary angiography shows the ability of coronary collaterals to provide adequate perfusion and preserve function at rest by demonstrating totally occluded coronary vessels without historical, electrocardiographic, or ventriculographic evidence of myocardial infarction.2A These noninfarcted, entirely collateral-dependent myocardial regions (NIECDMRs) -encountered in 28-50% of all total occlusions present a unique opportunity to assess the capabilities of the human collateral circulation to provide perfusion during exercise. However, an exercise study must be able to correlate coronary lesions with their respective regionally perfused myocardium. Exercise electrocardiography has been used to assess collateral function, but does not provide the regional specificity required to evaluate collateral function during exercise, particularly in patients with multivessel coronary disease.5 Exercise myocardial perfusion imaging (MPI), which has a high regional specificity,t-allows coronary anatomy to be more confidently correlated with regional myocardial perfusion during exercise.In this study, we used regional analysis of exercise MPI to assess the ability of coronary collaterals to perfuse NIECDMRs. cardiac catheterization, an exercise ECG and thallium-201 MPI. Thirty-one consecutive patients who had at least one totally occluded coronary vessel that did not result in myocardial infarction were selected for the study. Methods Cardiac CatheterizationAll patients underwent cardiac catheterization by the Sones or Judkins technique. Coronary cineingiography and left ventriculography were performed at a filming rate of 30 or 60 frames/sec. Two angiographers reviewed the...

Significance of collateral circulation on peri‐infarct zone: Assessment with stress thallium‐201 scintigraphy

“…Berger et al (1980) and Eng et al (1982) suggest that whether collaterals arejeopardized or not may not be a major determinant affecting stress-induced ischemia, and our results are in agreement with the reports. However, Rigo et al (1979) reported that nonjeopardized coronary collateral prevented stressinduced ischemia and the jeopardized one did not, since exercise-induced perfusion defect was not demonstrated when collaterals were nonjeopardized.…”

Pathophysiology of Coronary Collaterals

“…While modern myocardial perfusion imaging using positron emission tomography is able to measure actual perfusion, the only available studies investigating collateral function in response to exercise have employed thallium-201 perfusion imaging providing only a dichotomous measure of absent or present perfusion defects [22-24]. …”

Significance of extension of exercise-induced ischemia toward apex of left ventricle

“…Regarding the oxygen supply obtained by blood flow, the effort to limit the size of ischemia or infarct caused by coronary stenosis or occlusion was undertaken by coronary collateral [19,20] and microcirculation [21,22] in which a functional end arteries system exist as an end-capillary loop, particularly in the apical area within the ischemic territory [11]. Our results may illustrate the significance of the peripheral circulation for the recovery from ischemia in the apical side.…”