Angiographic Collateral Scores as Predictors of Salvageable Tissue in Coronary Artery Disease

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Summary of  Open Heart https://doi.org/10.1136/openhrt-2025-003930
Dr. Zia Mehmood et al.

Points

Chronic total occlusion is a common condition identified in approximately 20% of all coronary artery disease patients who undergo routine diagnostic angiograms.
The heart often adapts to long-term arterial blockages by growing microscopic collateral blood vessels that maintain a baseline level of protective blood flow.
Researchers analyzed 56 patients to compare conventional Rentrop collateral scores against gold-standard cardiac magnetic resonance imaging findings.
Patients exhibiting a Rentrop collateral score greater than one were significantly more likely to possess salvageable heart muscle rather than permanent scarring.
Each progressive step up in the Rentrop scoring system more than doubled the mathematical probability that the downstream heart tissue remained alive.

Summary

This study evaluated the efficacy of using a routine angiographic collateral scoring system to predict tissue-level myocardial viability in patients presenting with chronic total occlusion (CTO). Chronic total occlusion is highly prevalent, observed in approximately 20% of patients with established coronary artery disease who undergo diagnostic angiography. When a major epicardial coronary artery is completely blocked for months, the downstream myocardium does not automatically experience irreversible transmural scarring. Instead, the native coronary circulation frequently develops microscopic collateral vessels that form a functional detour. The investigators sought to determine whether standard angiographic visualization of these collaterals could reliably identify salvageable myocardium.

The researchers analyzed 56 patients diagnosed with CTO, comparing the routine angiogram-derived Rentrop collateral score against quantitative cardiac magnetic resonance (CMR) imaging, which remains the diagnostic gold standard for assessing myocardial viability. The tissue-level analysis demonstrated that the presence of robust collateral blood vessels provides a direct physiological indicator of living tissue downstream of the chronic obstruction. Specifically, patients displaying a Rentrop score greater than one were significantly more likely to possess viable myocardium. Multivariate statistical modeling revealed that the Rentrop collateral grade served as the only independent predictor of tissue viability identified within the cohort.

The predictive modeling demonstrated that each consecutive increase in Rentrop collateral grade more than doubled the probability that the affected downstream myocardial tissue remained viable rather than permanently scarred. These results indicate that utilizing a rapid, bedside indicator readily visible during conventional angiography allows clinicians to accurately risk-stratify patients directly inside the catheterization laboratory. This approach provides a practical diagnostic strategy in clinical settings where immediate access to advanced CMR imaging is restricted. By leveraging routine angiographic data to confirm myocardial viability, physicians can optimize patient selection, prioritize advanced imaging resources, and avoid high-risk, resource-heavy revascularization procedures in individuals unlikely to derive therapeutic benefit.

Link to the article: https://openheart.bmj.com/content/13/1/e003930

References

Mehmood, Z., Suresh, P., Li, R., Assadi, H., Gall, A., Kasmai, B., Thampi, K., Sawh, C., Geest, R. J. V. D., Ryding, A., Matthews, G., & Garg, P. (2026). Rentrop collateral grade predicts myocardial viability in chronic total occlusion on cardiac magnetic resonance. Open Heart, 13(1), e003930. https://doi.org/10.1136/openhrt-2025-003930