Role of collateral circulation in the recovery of left ventricular function after recanalization of chronic coronary total occlusion

Abstract

Aim. To obtain extended data on the impact of collateral circulation on the recovery of left ventricular (LV) function after recanalization of chronic coronary total occlusion (CTO), especially in patients with reduced left ventricle ejection fraction (LVEF).Material and methods. This single-center, prospective, non-randomized study included 20 patients with single-vessel CTO with reduced LVEF (<50%), confirmed by magnetic resonance imaging (MRI), who underwent successful recanalization. All patients were divided into 2 groups depending on the severity of collateral circulation. After 1, 3 and 6 months, MRI was repeated to assess LV function recovery.Results. All patients had prior myocardial infarction, while in 70% of cases — in the area of the occluded artery. A previous attempt to recanalize CTO was noted in 30%. The mean baseline LVEF according to echocardiography was 38,80±6,72%. The most common target vessel was the right coronary artery (n=17, 85%), followed by the circumflex and anterior descending arteries — 1 (5%) and 2 (10%) patients, respectively. In the group with high collateral circulation, the initial LVEF according to MRI was higher compared to the group with mild collateral circulation (35,8±7,33% vs 30,7±8,82%, p=0,17). After 6 months, MRI showed significant changes in end-diastolic volume (from 226±71,1 ml to 203±55,2 ml) and LV endsystolic volume (from 153±72,8 ml to 118±57,6 ml), as well as mean increase in LVEF by 3,3%, 4,8% and 5,2% at 1, 3 and 6 months, respectively (p=0,01 compared with baseline). The predictors of LVEF recovery in multivariate regression analysis were the initial LVEF according to MRI, and the filling rate of distal CTO bed on coronary angiography (R2=0,63).Conclusion. Successful percutaneous coronary intervention with CTO improves LV function in patients with ischemic cardiomyopathy, regardless of the degree of collateral circulation. LV function recovery generally occurs within 3 months after revascularization.