title: Does body mass index impact the early outcome of surgical revascularization? A comparison between off-pump and on-pump coronary artery bypass grafting.
abstract: OBJECTIVE
  To investigate the effects of body mass index (BMI) on early outcomes after revascularization using either on-pump or off-pump surgery.
  
  
  METHODS
  Data for 3714 of 4314 patients who underwent surgical revascularization at our institution between 1999 and 2008 were analysed. Patients were divided into two groups [off-pump coronary artery bypass (OPCAB); n = 1958 and on-pump coronary artery bypass (ONCAB); n = 1756] and further assigned into five classes according to their BMI (underweight <20 kg/m(2), normal 20-24.99 kg/m(2), overweight 25-29.99 kg/m(2), obese 30-34.99 kg/m(2) and morbidly obese ≥35 kg/m(2)). Thirty-day mortality, occurrence of major adverse cardiac events (MACEs), occurrence of major non-cardiac adverse events (MNCAEs) and length of in-hospital stay were analysed in relation to BMI only (whole cohort analysis), to BMI and chosen surgical method (ONCAB versus OPCAB) as well as confounding factors.
  
  
  RESULTS
  In the whole cohort analysis (n = 3714), no significant differences between BMI classes could be identified with regard to 30-day mortality (P = 0.78), MACEs (P = 0.72), MNCAEs (P = 0.45) or length of in-hospital stay (P = 0.94). With increasing BMI values, 30-day mortality tended to steadily increase (1.8% in BMI class 'underweight' vs 2.6% in BMI class 'morbidly obese'; P = 0.78), whereas MNCAEs tended to decrease with an increasing BMI (17.5% in BMI class 'underweight' vs 12.2% in BMI class 'morbidly obese'; P = 0.45). Compared with ONCAB, in patients with higher BMI values, OPCAB appeared to reduce slightly the frequency of 30-day mortality, MACEs and MNCAEs, while slightly increasing the length of in-hospital stay. Adjustment for other risk factors by covariate analysis in multiple regression models did not change the inferences drawn.
  
  
  CONCLUSIONS
  Our study did not detect significant differences between BMI classes with regard to mortality and morbidity. However, a slight trend towards a steadily increasing short-term mortality was detectable for patients with higher BMI values. When comparing ONCAB versus OPCAB, patients with higher BMI values appeared to have a weak tendency towards a reduced short-term morbidity and mortality in favour of OPCAB.
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Etem
authors: E
authors: Caliskan
authors: Plant Ecology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.
authors: Sabine
authors: S
authors: Güsewell
authors: Division of Biostatistics, Institute for Social and Preventive Medicine, University of Zurich, Zurich, Switzerland.
authors: Burkhardt
authors: B
authors: Seifert
authors: Institute for Anaesthesiology, University Hospital Zurich, Zurich, Switzerland.
authors: Oliver M
authors: OM
authors: Theusinger
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Christoph T
authors: CT
authors: Starck
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Jovana
authors: J
authors: Pavicevic
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Diana
authors: D
authors: Reser
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Tomas
authors: T
authors: Holubec
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Andre
authors: A
authors: Plass
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
authors: Volkmar
authors: V
authors: Falk
authors: Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland maximilian.emmert@usz.ch.
authors: Maximilian Y
authors: MY
authors: Emmert
mesh_terms: D015992:Body Mass Index; D001026:Coronary Artery Bypass / Q000379:methods; D047549:Coronary Artery Bypass, Off-Pump / Q000379:methods; D003324:Coronary Artery Disease / Q000150:complications / Q000453:epidemiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009204:Myocardial Revascularization / Q000379:methods*; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome
keywords: Body mass index; Coronary artery bypass surgery; Off-pump; On-pump