title: Restricted coronary flow reserve in patients with mitral regurgitation improves after mitral reconstructive surgery.
abstract: OBJECTIVE
  The purpose of this study was to assess coronary flow characteristics in patients with chronic mitral regurgitation (MR).
  
  
  BACKGROUND
  Coronary flow reserve (CFR) has been reported to be restricted in cases with left ventricular (LV) volume overload caused by aortic regurgitation and increased LV preload.
  
  
  METHODS
  The study populations consisted of 31 patients with nonrheumatic chronic MR. Eleven with chest pain and normal coronary arteries served as control subjects. Phasic coronary flow velocities were obtained in the proximal segment of the angiographically normal left anterior descending coronary artery at rest and during hyperemia (0.14 mg/kg/min adenosine infusion intravenously) using a 0.014-in. (0.036 cm), 15-MHz Doppler guide wire. Coronary flow reserve was obtained from the ratio of hyperemic/baseline time-averaged peak velocity (APV). Thirteen cases who underwent mitral valve reconstructive surgery were also studied 1 month after surgery.
  
  
  RESULTS
  Compared with control subjects, CFR was significantly reduced in cases with MR (2.1+/-0.5 vs. 33+/-0.6, respectively, p < 0.01) because baseline APV was significantly greater (28+/-8 vs. 19+/-6 cm/s, respectively, p < 0.01), although maximal hyperemic APV was not significantly different (56+/-14 vs. 61+/-16 cm/s, respectively, p = NS). Significant correlations were obtained between CFR and LV end-diastolic pressure (LVEDP) (r = 0.70, p < 0.01), LV mass index (r = 0.42, p < 0.01), LV end-diastolic volume (r = 038, p = 0.04) and MR volume (r = 0.39, p = 0.03), and stepwise regression analysis showed LVEDP was the most important determinant of CFR in MR (r2 = 0.49, p < 0.0001). This restricted CFR improved significantly after mitral valve reconstructive surgery (2.1+/-0.5 vs. 3.1+/-0.6, respectively, p < 0.01) because of reduction of baseline APV (28+/-8 vs. 21+/-8 cm/s, respectively, p < 0.01).
  
  
  CONCLUSIONS
  Coronary flow reserve is limited in cases with MR because of elevation of baseline resting flow velocity. This reduction of CFR correlates well with increase in LV preload, mass and volume overload, especially with increase in LV preload, and this restricted CFR improves after mitral valve surgery.
authors.affiliation: Department of Cardiology, Kobe General Hospital, Japan. jse@warp.or.jp
authors.forename: T
authors.initials: T
authors.lastname: Akasaka
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Hozumi
authors.forename: T
authors.initials: T
authors.lastname: Takagi
authors.forename: S
authors.initials: S
authors.lastname: Kaji
authors.forename: T
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ueda
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
authors.forename: S
authors.initials: S
authors.lastname: Morioka
authors.forename: J
authors.initials: J
authors.lastname: Yoshikawa
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003326:Coronary Circulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000503:physiopathology*; D011184:Postoperative Period; D012044:Regression Analysis; D016277:Ventricular Function, Left