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Relation between diastolic perfusion time and coronary artery stenosis during stress-induced myocardial ischemia
G Ferro1, C Duilio, L Spinelli
1Department of Internal Medicine, Federico II University, Naples, Italy.
Insights
Diastolic perfusion time closely relates to coronary stenosis severity during stress-induced myocardial ischemia. This finding suggests diastolic perfusion time may indirectly estimate the hemodynamic significance of coronary artery stenosis.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Stress-induced myocardial ischemia is limited by coronary obstruction and diastolic perfusion time.
- The relationship between these factors in humans remains understudied.
- Investigating this link is crucial for understanding myocardial dysfunction during ischemia.
Purpose of the Study:
- To assess the relationship between diastolic perfusion time and the degree of coronary stenosis.
- To compare this relationship across different stress test modalities.
Main Methods:
- Nine patients with proximal left anterior descending coronary artery stenosis were studied.
- Three randomized stress tests were performed: upright bicycle, supine bicycle, and transesophageal atrial pacing.
- Diastolic perfusion time, hemodynamic parameters, and stenosis severity (quantitative coronary angiography) were measured at the ischemic threshold.
Main Results:
- Diastolic perfusion time at the ischemic threshold strongly correlated with minimal stenosis diameter (r=0.97) and percent diameter stenosis (r=0.92).
- These correlations were consistent across all tested stress modalities.
- Heart rate and rate-pressure product did not significantly correlate with stenosis severity at the ischemic threshold.
Conclusions:
- A significant relationship exists between coronary stenosis severity and diastolic perfusion time during stress-induced myocardial ischemia.
- Diastolic perfusion time at the ischemic threshold can serve as an indirect indicator of coronary stenosis hemodynamic significance.
- This finding holds true despite varying hemodynamic responses across different stress tests.
Background:
Experimental studies have demonstrated that during stress-induced myocardial ischemia, coronary obstruction and diastolic perfusion time are factors that limit subendocardial perfusion and correlate to degree of myocardial dysfunction. The relation between these two factors has not yet been investigated in humans. The aim of the present study was to assess the relation between diastolic perfusion time and degree of coronary stenosis during different types of stress tests.
Methods And Results:
Nine patients with isolated and proximal stenosis of the left anterior descending coronary artery were selected. Patients underwent three different randomized stress tests (upright, supine bicycle stress test, and transesophageal atrial pacing). Diastolic perfusion time, heart rate (RR interval), and systolic and diastolic pressures were measured during the test and at the ischemic threshold (0.1-mV ST-segment depression). Angiographic measurements of coronary stenosis were evaluated by quantitative coronary angiography. At the ischemic threshold, significant differences among tests were found in heart rate (P < .05), systolic pressure (P < .001), and diastolic pressure (P < .05). In each stress test, diastolic perfusion time at the ischemic threshold was closely correlated with minimal stenosis diameter (r = .97; P < .001) and percent diameter stenosis (r = .92; P < .001) with no difference among the tests. In contrast, heart rate, rate-pressure product, and time to ischemic threshold were not significantly correlated with percent diameter stenosis and minimal stenosis diameter. No significant correlation was observed at the ischemic threshold between diastolic perfusion time and corresponding values of heart rate, despite the close correlation at rest (r = .95; P < .001).
Conclusions:
Despite differences in associated hemodynamic responses to various stress tests, a close relation exists between stenosis severity and diastolic perfusion time at the onset of stress-induced myocardial ischemia. Therefore, diastolic perfusion time at the ischemic threshold may be an indirect estimate of the hemodynamic significance of coronary stenosis.