Systolic Wall Stress May Affect the Intramural Coronary Blood Flow Velocity in Myocardial Hypertrophy, Independently on the Left Ventricular Mass

Abstract

We sought to evaluate the relationship between left ventricular systolic wall stress (LV-SWS) and coronary artery blood flow velocity in patients with LV hypertrophy (LVH). The study population comprised 38 patients, aged 66.7 +/- 12.7, who were divided into two groups based on the LV-SWS median value. Group A included 19 patients at "low-stress" (92.0 +/- 18.0 mmHg/cm2) and group B other 19 patients at "high-stress" (134.2 +/- 32.3 mmHg/cm2) (P < 0.002). Coronary blood flow velocities were measured both in the left anterior descending (LAD) and in the intramural (IM) arteries. There were no significant between-group differences in the main clinical and echocardiographic parameters. Diastolic velocity in the LAD was also comparable, while it was higher in the IM arterioles of patients from group B than from group A (peak velocity 110.9 +/- 35.2 cm/s vs 92.0 +/- 29.4 cm/s, P < 0.02; mean velocity 78.6 +/- 28.8 vs. 56.0 +/- 20.2 cm/s, P < 0.01, respectively). Overall, moderate, but significative, linear correlation was found between IM peak and mean diastolic velocity and LV-SWS (r = 0.41, P = 0.01, and r = 0.44, P = 0.007, respectively), whereas there was no correlation with wall thickening and LV mass. Main findings from the present study likely suggest that in patients with mild-to-moderate LVH, high blood flow velocity in the IM arterioles, but not in the LAD, may be related to an increase in LV-SWS, rather independent on the absolute LV mass.