title: Regional difference of microcirculation in patients with asymmetric hypertrophic cardiomyopathy: transthoracic Doppler coronary flow velocity reserve analysis.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors: Clinic for Cardiology, Clinical Center of Serbia, Belgrade, Serbia. misa.tesic@gmail.com
authors: Milorad
authors: M
authors: Tesic
authors: Ana
authors: A
authors: Djordjevic-Dikic
authors: Branko
authors: B
authors: Beleslin
authors: Danijela
authors: D
authors: Trifunovic
authors: Vojislav
authors: V
authors: Giga
authors: Jelena
authors: J
authors: Marinkovic
authors: Olga
authors: O
authors: Petrovic
authors: Milan
authors: M
authors: Petrovic
authors: Jelena
authors: J
authors: Stepanovic
authors: Milan
authors: M
authors: Dobric
authors: Vladan
authors: V
authors: Vukcevic
authors: Goran
authors: G
authors: Stankovic
authors: Petar
authors: P
authors: Seferovic
authors: Miodrag
authors: M
authors: Ostojic
authors: Bosiljka
authors: B
authors: Vujisic-Tesic
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D003326:Coronary Circulation; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D012039:Regional Blood Flow; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000503:physiopathology