Mitral regurgitation progression following isolated coronary artery bypass surgery: frequency, risk factors, and potential prevention strategies.
BACKGROUND
Though de novo mitral regurgitation (MR) is frequently seen in patients who have undergone coronary artery bypass surgery (CABG), its incidence, predictors, and mechanisms are not known.


METHODS
Our surgical registry was screened for patients undergoing isolated CABG who had preoperative and postoperative resting echocardiograms performed at our institution with <or=2+ MR preoperatively. This yielded 438 patients. Progression to 3-4+ MR post-CABG was correlated with clinical, electrocardiographic, echocardiographic, and operative variables.


RESULTS
New 3-4+ MR developed in 11 (10%) of the 108 patients with no prior MR, 21 of the 180 (12%) patients with pre-CABG 1+ MR, and 37 of the 150 (25%) patients with pre-CABG 2+ MR. MR progression correlated with female gender (42% vs 27%, p=0.01), history of renal insufficiency (12% vs 5%, p=0.05), prior-CABG (30% vs 17%, p=0.01), lack of beta-blocker use (19% vs 35%, p=0.008), lower incidence of significant PDA stenosis grafted (88% vs 98%, p=0.003), lower preoperative LVEF (42+/-19% vs 50+/-17%, p=0.001), larger LV size (p=0.01), pre-CABG MR grade (p=0.0002), and pre-CABG presence of LBBB block (20% vs 4%, p<0.0001). Independent predictors of MR progression, pre-CABG, were female gender (p=0.002), history of renal insufficiency (p=0.05), lack of beta-blocker use (p=0.006), MR grade (p=0.02), and presence of LBBB (p=0.005).


CONCLUSIONS
Development of significant MR following isolated CABG is common and may be related to incomplete myocardium revascularization, especially in the PDA area and LV remodeling. Preoperative, beta-blocker use may be protective against its development.
Campwala
Saida Zen
SZ
Division of Cardiology, Loma Linda University Medical Center, Loma Linda, CA 90033, USA.
Bansal
Ramesh C
RC
Wang
Nan
N
Razzouk
Anees
A
Pai
Ramdas G
RG
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000379:methods; D003327:Coronary Disease / Q000150:complications / Q000601:surgery; D018450:Disease Progression; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control; D051437:Renal Insufficiency / Q000150:complications; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D014463:Ultrasonography
D000319:Adrenergic beta-Antagonists