Regional Difference of Microcirculation in Patients with Asymmetric Hypertrophic Cardiomyopathy: Transthoracic Doppler Coronary Flow Velocity Reserve Analysis

• Published in: Journal of the American Society of Echocardiography Vol. 26; no. 7; pp. 775 - 782
• Main Authors: Tesic, Milorad, Djordjevic-Dikic, Ana, Beleslin, Branko, Trifunovic, Danijela, Giga, Vojislav, Marinkovic, Jelena, Petrovic, Olga, Petrovic, Milan, Stepanovic, Jelena, Dobric, Milan, Vukcevic, Vladan, Stankovic, Goran, Seferovic, Petar, Ostojic, Miodrag, Vujisic-Tesic, Bosiljka
• Format: Journal Article
• Language: English
• Published: United States Mosby, Inc 01.07.2013
• Subjects: Adult; Blood Flow Velocity; Cardiomyopathy, Hypertrophic - diagnostic imaging; Cardiomyopathy, Hypertrophic - physiopathology; Cardiovascular; Case-Control Studies; Chi-Square Distribution; Coronary Angiography; Coronary Circulation; Coronary flow velocity reserve; Coronary microcirculation; Echocardiography, Doppler; Female; Humans; Hypertrophic cardiomyopathy; Linear Models; Male; Microcirculation; Middle Aged; Regional Blood Flow; Ventricular Outflow Obstruction - diagnostic imaging; Ventricular Outflow Obstruction - physiopathology; CFVR; NYHA; IVS; PW; LV; Coronary microcirculation; CFR; LAD; LVOTG; HOCM; 2D; HCM; RPP; PD; TDE; DDT; Coronary flow velocity reserve; Hypertrophic cardiomyopathy; HC; PET; Left ventricular; Left ventricular outflow tract gradient; Diastolic deceleration time; New York Heart Association; Rate pressure product; Interventricular septum; Posterior descending coronary artery; Transthoracic Doppler echocardiography; Hypertrophic cardiomyopathy without obstruction; Left anterior descending coronary artery; Two dimensional; Hypertrophic obstructive cardiomyopathy; Coronary flow reserve; Posterior wall; Positron emission tomography
• ISSN: 0894-7317; 1097-6795; 1097-6795
• DOI: 10.1016/j.echo.2013.03.023

To evaluate, by noninvasive coronary flow velocity reserve (CFVR), whether patients with asymmetric hypertrophic cardiomyopathy (HC), with or without left ventricular outflow tract obstruction, demonstrate significant regional differences of CFVR. We evaluated 61 patients with HC (27 men; mean age 49 ± 16 years), including 20 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 41 patients without obstruction (HCM). The control group included 20 age- and sex-matched subjects. Transthoracic Doppler echocardiography CFVR of the left anterior descending coronary artery (LAD) and the posterior descending coronary artery (PD) were performed, including calculation of relative CFVR as the ratio between CFVR LAD and CFVR PD. Compared with the controls, all the patients with HC had lower CFVR LAD (2.12 ± 0.53 vs 3.34 ± 0.67; P < .001) and CFVR PD (2.29 ± 0.49 vs 3.21 ± 0.65; P < .001). CFVR LAD in HOCM group in comparison with the HCM group was significantly lower (1.93 ± 0.42 vs 2.22 ± 0.55; P = .047), due to higher basal diastolic coronary flow velocities (0.40 ± 0.09 vs 0.33 ± 0.07 m/sec; P = .002), with similar hyperemic diastolic flow velocities (0.71 ± 0.16 vs 0.76 ± 0.19 m/sec; P = .330), respectively. There was no significant difference in CFVR PD between patients with HOCM and those with HCM (2.33 ± 0.46 vs 2.27 ± 0.50; P = .636), respectively. Relative CFVR was lower in the HOCM group compared with the HCM group (0.84 ± 0.16 vs 0.98 ± 0.14; P = .001). By multivariable regression analysis, left ventricular outflow tract gradient was the independent predictor of CFVR LAD (B = −0.24; P = .008) and relative CFVR (B = −0.34; P = .016). CFVR LAD and relative CFVR were significantly lower in patients with HOCM compared with patients with HCM. Regional differences of CFVR are present only in patients with significant left ventricular outflow tract obstruction, which suggests that obstruction per se, by increasing wall stress in basal conditions, leads to higher basal diastolic coronary flow velocities and results in lower CFVR in LAD compared with PD.