Increased Coronary Tortuosity Is Associated with Increased Left Ventricular Longitudinal Myocardial Shortening

Background: The mechanistic basis for tortuosity of the coronary arteries (TCA) is unclear. The aim of this study was to test the hypothesis that the relative degree of systolic longitudinal shortening of the left ventricle that deforms coaxially oriented coronary arteries is associated with TCA. Methods: Adult subjects undergoing coronary angiography and comprehensive echocardiography within 3 months were classified dichotomously as with (n = 32) or without (n = 42) TCA defined on the basis of number and severity of coronary angles. Systolic left ventricular (LV) longitudinal deformation was determined by mitral annular plane systolic excursion (MAPSE) from both B-mode displacement and tissue Doppler time-velocity integral; data were indexed to LV diastolic long-axis length. Results: There were no differences between groups with respect to age, gender, hypertension, or coronary artery disease. Patients with TCA had significantly (P<.01) lower LV mass index and a shorter total LV diastolic long-axis length (mean, 8.3 +/- 1.9 vs 9.1 +/- 2.2 cm; P<.01). Despite having a shorter length, those with TCA had greater MAPSE by both methods. MAPSE normalized to diastolic length was significantly greater (P <.01) in those with TCA, which remained the case after excluding subjects with reduced LV ejection fraction. Multiple linear regression found that lateral annular MAPSE had the largest effect size, with a 13-fold increase in likelihood for TCA for every 0.1 of normalized MAPSE. Conclusions: TCA is not associated with increased LV mass but rather with smaller hearts that have greater relative longitudinal shortening of the left ventricle. This finding suggests that TCA could represent an adaptive response to longitudinal systolic distortion of coaxially oriented coronary arteries that dynamically produce shear stresses associated with expansive coronary remodeling.