# Effect of Coronary Collateral Supply on Left Ventricular Global Longitudinal Strain after Recanalization of Chronic Total Occlusion

## TL;DR

This study examines how coronary collateral supply affects heart function improvement after treating blocked arteries.

## Contribution

It shows that poor collateral supply is linked to greater improvement in heart function after revascularization.

## Key findings

- Poor collateral groups showed significant improvement in global longitudinal strain after CTO-PCI.
- Well-developed collateral groups did not show significant improvement in strain measurements.
- Ejection fraction remained unchanged in both groups after treatment.

## Abstract

Percutaneous coronary intervention (PCI) to chronic total occlusion (CTO) is still a subject of debate. The primary goal of revascularization is to provide symptomatic relief and enhance left ventricular (LV) functions. Global longitudinal strain (GLS) is proven to be more sensitive than the ejection fraction (EF), especially for subtle ischemic changes. The purpose of this study was to investigate the improvement in LV GLS after revascularization of symptomatic stable coronary patients with single-vessel CTO, categorized according to their collateral supply grades. Sixty-nine patients with successful CTO-PCI were grouped, according to their collateral supply grades, as well-developed (WD) and poor collateral groups and followed-up for 3 months. Basal characteristics were similar for both groups, except for a lower EF (p = 0.04) and impaired GLS (p < 0.0001) in the poor collateral group. At the end of 3 months follow-up, symptomatic relief was similar in both groups (p = 0.101). GLS improvement reached statistical significance only for the poor collateral, not for the WD group (p < 0.0001 and p = 0.054, respectively). The EF did not change significantly in both groups. Poorly collateralized CTO lesions may not only result in baseline LV dysfunction, but also appear to carry potential for recovery after revascularization. This may not be the case for WD collaterals.