Impact of the left anterior descending artery wrapping around the left ventricular apex on cardiac mechanics in patients with normal coronary angiography.

Background: We examined the impact of left anterior descending (LAD) wrapping on left ventricular (LV) mechanics in patients with normal coronary angiography. Seventy-one patients with evidence of normal coronary angiography (LAD wrapping: n = 52, 73%) and LAD non-wrapping (n = 19, 27%) were included in the study. Using 2D-strain imaging, we measured LV longitudinal and circumferential (circ) strain (ε), systolic strain rate (SR), early (SR) and atrial (SR) diastolic SR, LV electromechanical dyssynchrony (TTP-SD), and LV twist and torsion in study groups.

Results: No significant difference in age, gender, body surface area (BSA), or ejection fraction (EF%) between groups. LAD-wrapping group showed higher deceleration time (DT) (P < 0.0001), global longitudinal ε % (P < 0.02), circ SR at the basal segments (P < .02), circ SR and SR and SR (P < 0.0001) at the apical segments and apical rotation compared with the non-wrapped group. LV twist was correlated negatively with LV electromechanical dyssynchrony (r = .25, P < 0.03) and positively with longitudinal ε (r = .47, P < .0001), circ ε (r = .55, P < .0001), circ SR (r = .23, P < .05), and circ SR (r = .55, P < .0001). Using multivariate regression analysis, DT: OR 0.932, CI 0.877-0.991, and P < 0.02 and circ at atrial diastole (SR): OR 0.000, CI .000-.271, and P < 0.03 were independent predictors of LAD wrapping around LV apex.

Conclusion: Wrapped LAD is associated with better myocardial relaxation and rotational mechanics in patients with normal coronary angiography. This could explain the worse prognosis in such population when LAD occlusion acutely emerges.