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[The coronary collaterals influence in the recovery phase after exercise-induced myocardial ischemia]
F Bonetti1, A Margonato, A Mailhac
1Divisione Cardiologia, Istituto Scientifico Ospedale San Raffaele, Milano.
Insights
Coronary collaterals improve recovery from exercise-induced myocardial ischemia. Patients with visible collaterals showed faster ST segment return and smaller ischemic areas after stress tests.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Exercise-induced myocardial ischemia is a common concern in patients with coronary artery disease.
- The role of coronary collaterals in mitigating ischemia during exercise has been understudied.
Purpose of the Study:
- To investigate the impact of coronary collaterals on recovery from exercise-induced myocardial ischemia.
- To assess if visible collaterals influence the physiological response to exercise stress in patients with coronary artery disease.
Main Methods:
- Sixty patients with low threshold effort angina and coronary artery disease underwent serial exercise testing.
- Coronary angiography was used to assess disease severity and collateralization (Cohen and Rentrop classification).
- Thallium 201 myocardial perfusion scintigraphy was performed on the second day of testing.
Main Results:
- Patients with visible collaterals (Group A) had more severe coronary artery disease (Gensini score: 46.9) compared to those without (Group B, Gensini score: 28.6).
- Despite similar maximal ST depression and exercise duration, Group A showed a significantly faster ST segment return to baseline (5.5 vs 11.7 minutes) and a smaller ischemic area (301 vs 621).
- Time and rate-pressure product to 1 mm ST depression were lower in Group A, indicating a different physiological response.
Conclusions:
- Visible coronary collaterals significantly enhance the recovery from exercise-induced myocardial ischemia.
- The presence of collaterals appears to precondition the myocardium, leading to improved outcomes during and after exercise stress.
- These findings highlight the protective role of collateral circulation in managing ischemic heart disease.
Abstract:
The role of coronary collaterals in conditioning the recovery from exercise-induced myocardial ischaemia has not been investigated. We studied 60 patients (54 men, age 59.3 +/- 6.7 years) with low threshold effort angina and documented coronary artery disease, who underwent repeat exercise testing in 2 consecutive days. On the second day, Thallium 201 stress/rest myocardial perfusion scintigraphy was also performed. At angiography, 30 patients (Group A), had more severe disease (Gensini score: 46.9 +/- 16) and angiographically visible collaterals (grade 2-3 Cohen and Rentrop classification) perfusing the ischaemic zone; the other 30 (Group B), had lesser disease (Gensini score: 28.6 +/- 18, p less than 0.001 vs Group A) and non visible collaterals to the ischaemic areas. Maximal ST depression and total exercise duration were similar in the 2 groups (2.5 +/- 0.6 vs 2.5 +/- 0.7 mV and 6.2 +/- 1.8 vs 6.8 +/- 1.9 min, respectively) but time and rate-pressure product to 1 mm ST depression were lesser in Group A (3.5 +/- 0.8 vs 4.8 +/- 0.6 min, p less than 0.01, and 14189 +/- 2451 vs 16081 +/- 2215 b/min x mmHg, p less than 0.04). Surprisingly, in Group A, the ST segment returned to the baseline more rapidly (5.5 +/- 1.6 vs 11.7 +/- 3.3 min, p less than 0.001), and the ischaemic area [time (s) x ST (mV)], measured in the recovery period, was also smaller (301 +/- 163 vs 621 +/- 260, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)