title: The influence of time on the characteristics and risk factors for patients submitted to myocardial revascularization.
abstract: OBJECTIVE
  To compare the clinical and surgical profile between two groups of patients submitted to Myocardial Revascularization (MCR) surgery at the Instituto de Cardiologia of Rio Grande do Sul with a ten year interval, to observe its influence upon MCR hospital mortality and to verify the predictability of this result using the risk score.
  
  
  METHODS
  A retrospective cohort study involving 307 patients who underwent MCR surgery within a six month period during 1991/92 (INITIAL group, n=153) or 2001/02 (CURRENT group, n=154). Demographic characteristics, heart disease, comorbidities and surgical events were analyzed to compare the groups and to define the hospital mortality risk score (based on the Cleveland Clinic method).
  
  
  RESULTS
  The CURRENT group was older, had more severe heart condition (functional class, incidence of heart failure and number of vessels with severe lesions) and a greater prevalence of comorbidities. The INITIAL group had a higher prevalence of nonelective surgery. Both groups had similar mean risk scores (2.8 +/- 3.1 for INITIAL and 2.2 +/- 2.5 for CURRENT) and hospital mortality rates (3.3% and 1.9% respectively). These figures are comparable to those for reported by Cleveland Clinic (for a risk score of 3 the predicted mortality range between 2.0 %; using a confidence level of 95% the predicted mortality is between 0 and 4.3%; and actual mortality confirmed by the study was 3.4%).
  
  
  CONCLUSIONS
  Patients currently submitted to MCR are older and in worse clinical condition (heart and systemic) than those operated on ten years ago; however, the risk scores and hospital mortality rates were slightly higher in the INITIAL group. The higher number of nonelective surgical interventions could have contributed to this. A risk score can be used to identify patients that require a higher level of care and to predict surgical outcomes.
authors.affiliation: Instituto de Cardiologia do Rio Grande do Sul, Fundação Universitária de Cardiologia, Porto Alegre, RS.
authors.forename: Flávia H
authors.initials: FH
authors.lastname: Feier
authors.forename: Roberto T
authors.initials: RT
authors.lastname: Sant'Anna
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia
authors.forename: Felipe de
authors.initials: Fd
authors.lastname: Bacco
authors.forename: Edemar
authors.initials: E
authors.lastname: Pereira
authors.forename: Marisa
authors.initials: M
authors.lastname: Santos
authors.forename: Altamiro Reis
authors.initials: AR
authors.lastname: da Costa
authors.forename: Ivo A
authors.initials: IA
authors.lastname: Nesralla
authors.forename: João Ricardo M
authors.initials: JR
authors.lastname: Sant'Anna
mesh_terms: D000368:Aged; D001938:Brazil / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization / Q000401:mortality*; D012720:Severity of Illness Index; D013997:Time Factors