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[Evaluation of coronary reserve in angina pectoris with angiographically normal coronary arteries]
Insights
This study found that patients with angina and normal coronary arteries do not have reduced coronary reserve, despite experiencing myocardial ischemia. However, coronary artery disease patients showed significantly reduced coronary reserve, linking ischemia to impaired coronary flow.
Area of Science:
- Cardiology
- Physiology
- Medical Research
Context:
- Investigating coronary reserve in patients with angina and normal coronary arteries versus coronary artery disease.
- Utilizing rapid atrial pacing and dipyridamole infusion to assess myocardial ischemia and coronary blood flow.
- Measuring coronary sinus flow and myocardial metabolism via lactate extraction coefficient.
Purpose:
- To determine if reduced coronary reserve is present in patients with angina and angiographically normal coronary arteries.
- To compare coronary reserve and myocardial ischemia between patients with coronary artery disease, angina with normal arteries, and healthy controls.
- To elucidate the relationship between myocardial ischemia and coronary reserve in different patient groups.
Summary:
- Patients with angina and normal coronary arteries showed myocardial ischemia during pacing but maintained normal coronary reserve with dipyridamole.
- Coronary artery disease patients exhibited significantly reduced coronary reserve and myocardial ischemia.
- Angiographically normal coronary arteries with ischemia did not correlate with reduced coronary reserve, unlike in coronary artery disease.
Impact:
- Challenges the assumption of reduced coronary reserve in all angina patients.
- Highlights the critical role of diminished coronary reserve in myocardial ischemia associated with coronary artery disease.
- Provides insights for diagnosing and managing ischemic heart conditions based on coronary reserve assessment.
Abstract:
Coronary reserve was studied: 1) during rapid atrial pacing and then, 2) during dipyridamole infusion (0.6 mg/Kg/4 min) in 3 groups of subjects: 13 patients with angina pectoris and angiographically normal coronary arteries (ANC) with proven myocardial ischaemia during atrial pacing, 15 patients with coronary artery disease (COR) and 17 normal controls with normal coronary angiography and atrial pacing. Coronary sinus flow (QCS) was measured by thermodilution and myocardial metabolism studied by the coefficient of lactate extraction (K). At maximal pacing rates, K remained 15 p. 100 in the control group (average 24 +/- 7 p. 100) but was inversed in the ANC (-3 +/- 10 p. 100) and COR groups (-27 +/- 38 p. 100). The risk in QCS was low in the COR group (+60 +/- 33 p. 100) p less than 0.02, but significant in the ANC group (+104 +/- 57 p. 100) and normal controls (+107 +/- 41 p. 100). Coronary reserve, calculated as the percentage increase in QCS with dipryridamole, was found to be the same in the ANC group (+225 +/- 79 p. 100) as in normal subjects (+191 +/- 81 p. 100) but was low in the COR group (74 +/- 42 p. 100, p less than 0,001). Therefore, no reduction in coronary reserve was shown in patients with angina and normal coronary arteries whilst the myocardial ischaemia in coronary disease does seem to be related to an amputation of the coronary reserve.