Functional limitation of recruitable collaterals in human subjects--ST segment deviation on intracoronary electrocardiogram during transient coronary occlusion induced by balloon inflation
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H Yoshio1, M Shimizu, R Takeda
1Second Department of Internal Medicine, Kanazawa University School of Medicine, Japan.
Insights
Transient recruitable collaterals offer limited protection during acute coronary occlusion. Even well-developed collaterals may not prevent transmural ischemia in certain coronary branches.
Area of Science:
- Cardiology
- Interventional Cardiology
- Ischemic Heart Disease
Background:
- Coronary artery disease management often relies on collateral circulation to mitigate ischemia during occlusive events.
- The functional capacity of recruitable collaterals during acute coronary occlusion remains incompletely understood.
Observation:
- Three patients undergoing left anterior descending (LAD) artery angioplasty exhibited ST elevation on precordial ECG and ST depression on intracoronary ECG.
- Despite no visible baseline collaterals, all patients demonstrated transient recruitable collaterals to the LAD, but not to diagonal branches.
Findings:
- Intracoronary ECG changes suggest potential endocardial ischemia in the LAD, possibly compensated by recruitable collaterals.
- Precordial ST elevation may indicate transmural ischemia in diagonal branches, where collaterals were insufficient to prevent damage.
Implications:
- Recruitable coronary collaterals have functional limitations during acute ischemia, even when well-developed.
- These findings highlight the complex interplay between collateral function and ischemic severity in different myocardial territories.
Abstract:
Three patients showed ST elevation on precordial electrocardiogram and ST depression on intracoronary electrocardiogram during angioplasty of the left anterior descending coronary arteries (LAD). While none of the patients had spontaneously visible collaterals, all showed transient recruitable collaterals to the LAD. No evident collaterals into the diagonal branches were observed. Possibly, if the intracoronary electrocardiogram represents the potential changes of the epicardial surface in the vicinity of the guidewire tip, then endocardial ischemia may have developed even though epicardial ischemia was not observed, due to relatively sufficient blood flow through the recruitable collaterals to the LAD. ST elevation on the precordial electrocardiogram may have represented epicardial and endocardial ischemia of the diagonal branches, where the recruitable collaterals could not protect against transmural ischemia. These phenomena suggests that the recruitable collaterals are functionally limited during acute coronary occlusion, even though the collaterals are well developed.