title: Clinical and echocardiographic determinants of long-term survival after surgical myectomy in obstructive hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Surgical myectomy has been the standard treatment for patients with drug-refractory obstructive hypertrophic cardiomyopathy. The clinical and echocardiographic predictors of long-term survival and freedom from cardiovascular morbidity after myectomy have been unclear.
  
  
  RESULTS
  We studied a consecutive cohort of 338 adult patients (age at operation 47+/-14 [range 18 to 77] years, 60% male) who underwent myectomy at our institution. Preoperative resting left ventricular outflow tract (LVOT) gradient was 66+/-32 mm Hg (range 5 to 158 mm Hg). Early postoperative mortality was 1.5% (5 deaths): 4 deaths occurred between 1978 and 1992, and 1 death occurred between 1993 and 2002. During long-term follow-up, 83% of patients reported an improvement to functional class I or II. The majority of patients (98%) had no resting LVOT gradient. Long-term survival was excellent, with 98+/-1% survival at 1 year, 95+/-1% at 5 years, and 83+/-3% at 10 years after myectomy. Multivariable Cox regression analysis identified 5 predictors of overall mortality: (1) age > or =50 years at surgery (hazard ratio [HR] 2.8, 95% CI 1.5 to 5.1, P=0.001), (2) female gender (HR 2.5, 95% CI 1.5 to 4.3, P=0.0009), (3) history of preoperative atrial fibrillation (HR 2.2, 95% CI 1.2 to 4.0, P=0.008), (4) concomitant CABG (HR 3.7, 95% CI 1.7 to 8.2, P=0.001), and (5) preoperative left atrial diameter > or =46 mm (HR 2.9, 95% CI 1.6 to 5.4, P=0.0008). Significant predictors of late major cardiovascular events found on multivariable analysis were (1) female gender (HR 3.3, 95% CI 2.0 to 5.4, P<0.0001), (2) history of preoperative atrial fibrillation (HR 1.9, 95% CI 1.1 to 3.3, P=0.02), and (3) preoperative left atrial diameter > or =46 mm (HR 2.5, 95% CI 1.5 to 4.3, P=0.0008).
  
  
  CONCLUSIONS
  Myectomy provides excellent relief for LVOT obstruction in patients with hypertrophic cardiomyopathy. Preoperative clinical and echocardiographic variables can predict long-term outcome after myectomy.
authors.affiliation: Division of Cardiology, Toronto General Hospital, 4N-506, 200 Elizabeth St, Toronto, Ontario, Canada M5G 2C4. anna.woo@uhn.on.ca
authors.forename: Anna
authors.initials: A
authors.lastname: Woo
authors.forename: William G
authors.initials: WG
authors.lastname: Williams
authors.forename: Richard
authors.initials: R
authors.lastname: Choi
authors.forename: E Douglas
authors.initials: ED
authors.lastname: Wigle
authors.forename: Evelyn
authors.initials: E
authors.lastname: Rozenblyum
authors.forename: Katie
authors.initials: K
authors.lastname: Fedwick
authors.forename: Samuel
authors.initials: S
authors.lastname: Siu
authors.forename: Anthony
authors.initials: A
authors.lastname: Ralph-Edwards
authors.forename: Harry
authors.initials: H
authors.lastname: Rakowski
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001281:Atrial Fibrillation; D006348:Cardiac Surgical Procedures / Q000401:mortality; D002312:Cardiomyopathy, Hypertrophic / Q000401:mortality* / Q000601:surgery*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D012737:Sex Factors; D016019:Survival Analysis; D016896:Treatment Outcome