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Variations in right and left coronary blood flow in man with and without occlusive coronary disease
Insights
Coronary artery occlusion severity significantly impacts myocardial blood flow. Critical flow reduction only occurs with over 90% coronary artery occlusion, impacting revascularization decisions.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Physiology
Background:
- The relationship between coronary artery occlusion and myocardial blood flow is clinically significant, especially with increasing revascularization procedures.
- Adequate assessment of coronary occlusion severity is crucial for guiding interventions.
Purpose of the Study:
- To compare the severity of coronary occlusion with the degree of reduction in regional myocardial blood flow.
- To investigate the correlation between angiographic findings and actual blood flow in coronary arteries.
Main Methods:
- Regional myocardial blood flow was measured using 85-Kr washout in 34 patients.
- Coronary artery occlusions were assessed via selective coronary arteriography (Sones technique) and graded by percentage of luminal diameter reduction.
Main Results:
- Significant stenosis (>50%) was found in 10 of 26 right coronary arteries, associated with reduced flow compared to normal arteries.
- Dominant right coronary arteries showed higher flows and a greater incidence of occlusion than non-dominant ones.
- Left coronary arteries with >50% occlusion had reduced blood flow (68 ml/min/100g) compared to normal (84 ml/min/100g); critical reduction was observed only with >90% occlusion.
Conclusions:
- Myocardial blood flow is reduced with coronary artery stenosis, but critical reduction requires severe occlusion (>90%).
- Angiographic assessment of coronary occlusion severity should be correlated with functional blood flow measurements for accurate clinical decisions.
Abstract:
The relation of angiographically recognized coronary occlusion to regional myocardial blood flow has not been studied adequately in spite of its clinical significance. This is particularly important, as revascularization procedures, based on angiographic studies, are being performed with increasing frequency. To compare the severity of reduction in flow to the severity of coronary occlusion, regional myocardial blood flow (85-Kr washout) was measured in 34 patients. Selective coronary anteriograms were obtained using the Sones technique, and occlusions were graded as a percentage of luminal diameter. Of 26 right coronary arteries for which satisfactory arteriograms and coronary blood flow measurements were obtained, 16 were normal and 10 had significant stenosis (greater than 50%). Dominant right coronary arteries appeared to have high flows (67 plus or minus 6 ml min-minus1 per 100 g muscle) and a greater incidence of occlusion (10 of 20) than nondominant arteries, which had less flow (41 plus or minus 2 ml min-minus1 per 100 g muscle) and a lower incidence of occlusion (1 of 8). Coronary blood flow in 16 normal left coronary arteries was 84 plus or minus 5 ml min-minus1 per 100 g muscle and in 15 with 50 per cent or greater occlusion, 68 plus or minus 3 ml min-minus1 per 100 g muscle. Though coronary blood flow appeared reduced when lesions of both the right and left coronary arteries were present, a critical reduction was seen only when occlusion was greater than 90 per cent.