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[Quantification of myocardial ischemia in regions dependent on occluded coronary arteries in patients without
C Santana Boado1, J Candell Riera, S Aguadé Bruix
1Servicio de Cardiología, Hospital General Universitari Vall d'Hebron, Barcelona.
Insights
Myocardial ischemia can occur in coronary arteries without complete occlusion. The extent of ischemia is greater in regions with occluded arteries, especially without good collateral circulation.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Coronary artery disease (CAD) is a leading cause of mortality worldwide.
- Assessing myocardial ischemia in non-infarcted regions is crucial for risk stratification.
- The role of collateral circulation in modulating ischemia in occluded arteries requires further investigation.
Purpose of the Study:
- To evaluate myocardial ischemia in regions supplied by occluded coronary arteries.
- To compare ischemic burden in territories of occluded versus non-occluded arteries.
- To investigate the impact of collateral circulation on ischemia in occluded coronary arteries.
Main Methods:
- 149 patients with coronary artery disease and no prior myocardial infarction were studied.
- 99mTc-MIBI SPECT (single-photon emission computed tomography) and coronary angiography were performed.
- Quantification of reversible defects in myocardial regions based on rest and stress uptake differences.
Main Results:
- 36% of patients had at least one occluded coronary artery.
- Reversible defects were consistently observed in territories of occluded left anterior descending and right coronary arteries.
- Ischemia extent was higher in regions dependent on occluded arteries, particularly with poor collateral flow.
Conclusions:
- Myocardial ischemia is present in territories of occluded coronary arteries, even without infarction.
- The left anterior descending and right coronary arteries showed consistent reversible defects upon occlusion.
- Good collateral circulation mitigates the extent of myocardial ischemia in occluded coronary artery territories.
Introduction And Objectives:
The aim of this study is to assess myocardial ischemia in regions with no infarction dependent occluded coronary arteries.
Patients And Methods:
149 patients with proved coronary artery disease and without previous myocardial infarction were studied by 99mTc-MIBI SPECT (long protocol) and coronary angiography. The extent of the uptake reversibility was quantified in 3 regions (antero-septal, inferior and lateral) of the polar maps, assessing the percentage of each region that had a > 10% difference resulting from the rest uptake minus the stress uptake. The regions dependent on one occluded artery were compared to those dependent on non-occluded arteries. In the regions dependent on one occluded artery a comparison was also made between those which had a good collateral circulation and those which did not.
Results:
Fifty-four out of 149 patients (36%) had at least one occluded coronary artery (20 anterior descending, 22 right and 27 circumflex coronary arteries). In the visual analysis, reversible defects were observed in all patients with occlusion of the anterior descending and the right coronary artery, but only in half of the occlusions of the circumflex coronary artery. The extent of this reversibility was significantly higher in the regions dependent on occluded arteries and was highly variable, though lower when good collateral circulation was present.
Conclusions:
Reversible defects were always observed in the occlusions of the left anterior descending and right coronary arteries, but only in half of those of the circumflex artery. The extent of the ischemia was higher in the regions dependent on one occluded coronary artery, mainly when there was an absence of good collateral circulation.