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[Indices of left ventricular diastole in patients with unstable angina and angiographically documented collateral
Insights
Collateral circulation vessels (CCV) did not improve left ventricular diastolic function in patients with unstable angina, suggesting they provide insufficient blood flow to ischemic myocardium. This indicates potential myocardial ischemia despite the presence of CCV.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Context:
- Unstable angina is characterized by significant coronary artery stenosis.
- Left ventricular diastolic function is crucial for cardiac health.
- Collateral circulation vessels (CCV) may play a protective role in coronary artery disease.
Purpose:
- To evaluate the impact of CCV on left ventricular diastolic function in patients with unstable angina.
- To compare diastolic parameters between patients with and without CCV and a control group.
Summary:
- Patients with unstable angina exhibited prolonged time constant (T), indicating slowed relaxation and myocardial ischemia.
- No significant difference in time constant T was observed between patients with and without CCV.
- Left ventricular diastolic parameters (EDVI, EDP) were not influenced by the presence of CCV.
Impact:
- CCV appear insufficient to restore adequate myocardial blood flow in the setting of significant coronary stenosis.
- Findings suggest that CCV do not significantly alter left ventricular diastolic dysfunction in unstable angina.
- This research highlights the limitations of collateral circulation in preventing ischemia-induced diastolic impairment.
Abstract:
23 patients (20 males, 3 females) aged 26-62 (mean 45.9 +/- 9.9) with unstable angina underwent the study to evaluate the effect of collateral circulation vessels (CCV) on left ventricular diastole. There was no evidence of myocardial infarction in the past and ejection fraction was normal (EF greater than 60%). At least one branch of left coronary artery was significantly stenosed (more than 75% of a vessel lumen). Patients were divided into two groups: group I -- with CCV, group II -- without CCV. Obtained data were compared between these groups and with the control group (K) consisted of 10 persons. CCV were only observed if a coronary artery was occluded or subtotally stenosed. When a coronary artery was occluded, CCV could prevent myocardial infarction. Time constant (T) prolongation (43.6 +/- 10.8 vs 32 58 +/- 7.9 ms, p less than 0.05 for groups I and K and 49.31 +/- 18.8 vs 32.58 +/- 7.9 ms, p less than 0.02 for groups II and K) testifies to relaxation slowing down in patients with unstable angina, which indicates left ventricular myocardial ischemia. Lack of CCV influence on time constant T (43.6 +/- 10.8 vs 49.31 +/- 18.8 ms, p less than 0.5) as well as remaining left ventricular diastolic parameters (EDVI, EDP) seems that CCV were an insufficient source of a blood flow to myocardium supplied by a stenosed artery.