Value of echocardiography for observing left ventricular hypertrophy in the diagnosis of myocardial microvascular damage in hypertensives.

Objective To investigate the value of the echocardiographic observation of the left ventricular hypertrophy (LVH) in diagnosing myocardial microvascular damage in patients with essential hypertension (EH). Methods After intravenous in-jection with Quanfuxian (a contrast agent consisting of albumin and C 3 F 8 prepared by Nanfang Hospital), the values of A (the maximum number of microbubbles accumulating in the local tissues for assessing the density of local microvessels), β(the filling velocity of contrast agent for evaluating local blood flow velocity) and A·β(the product of A and βfor estimating local myocardial blood flow) at rest and after dipyridamole injection were measured by intermittent harmonic imaging with myocar-dial contrast echocardiography (MCE). The ratios of A and βalong with the microvascular coronary flow velocity reserve (CFVR) were also calculated. Results Compared with the control group, the rest values of A, βand A·βin EH patients were higher, especially in those with LVH. After dipyridamole injection, the values of A, β, A·βand the ratios of A and β, along with CFVR as well, were significantly lowered (P0.01), and the reductions were especially obvious in LVH cases. As the hy-pertension exacerbated, the values of A and A·βtended to increase in positive correlation with systolic and diastolic blood pressure (P0.01), while the ratio of A and CFVR were decreased, the latter was inversely correlated with diastolic blood pres-sure (r=-0.55, P0.01). Positive correlations were noted of the values of A and A·βwith the left ventricular mass and left ventricular mass index (P0.01). Conclusions EH patients, especially those with LVH, are characterized by increased rest myocardial microvascular blood flow, impaired myocardial microvascular flow reserve and endothelium independent vasodi-lation relaxing ability, and reduced capillary density, and these conditions tend exacerbate as the disease worsens. Microvascu-lar function impairment should be suspected when complication of LVH arises in the EH patients. As a new important nonin-vasive technique, MCE can be a promising modality for diagnosing microvascular disease in essential hypertension.