Assessment of Coronary Flow with Transthoracic Color Doppler Echocardiography in Patients with Hypertrophic Cardiomyopathy

BACKGROUND: Recent advances in echocardiography have allowed assessment of flow velocity in the epicardial coronary arteries of patients with ischemic heart disease, using transthoracic color Doppler echocardiography (TTDE). However, few data are available regarding coronary blood flow in patients with hypertrophic cardiomyopathy (HCM). OBJECTIVE: To assess the epicardial coronary arteries of patients with HCM. MATERIAL AND METHODS: A group of 25 patients with HCM was assessed prospectively (mean age 57 ± 21 years, 11 male) using TTDE; flow velocities in the epicardial coronary arteries were measured and compared with those obtained in 10 age- and gender-matched controls. Analysis of the diastolic spectral waveform included flow velocity integral (VTI), peak velocity, deceleration time, and deceleration slope measurements, while systolic waveform analysis included peak flow measurement and morphology assessment (positive, absent or negative). An analysis of variance (ANOVA) test was used for multiple comparisons for variables with a normal distribution, and a Kruskal-Wallis test was used for variables with non-Gaussian distribution. RESULTS: Patients with HCM exhibited an increase in diastolic flow velocity with a rapid deceleration slope and a systolic slope which was decreased, absent or reversed, compared to normal subjects. On linear regression analysis there was no correlation with the type of hypertrophy or magnitude of the intraventricular pressure gradient in patients with obstructive HCM. CONCLUSION: In patients with HCM, noninvasive assessment with TTDE revealed abnormal findings in the distal flow of the epicardial coronary arteries, very similar to those seen in the no-reflow phenomenon. These findings were independent of the type of hypertrophy and magnitude of the intraventricular pressure gradient in patients with obstructive HCM.