Predictors of mortality in patients over 70 years-old undergoing CABG or valve surgery with cardiopulmonary bypass.

OBJECTIVE

To identify risk factors in septuagenarians and octogenarians submitted to cardiovascular surgery with cardiopulmonary bypass (CPB).

METHODS

Per-operative variables of 265 patients over 70 years of age were analyzed. 248 (93.6%) were septuagenarians and 17 (6.4%) octogenarians.

RESULTS

Overall mortality did not differ between the groups, nor did the type of procedure (CABG or valvular) (P=0.545). Pre-operative variables did not increase the death risk, nor did the use of arterial or venous grafts (P=0.261), or the number of grafts per patient (P=0.131). CPB and cross-clamp time are associated with higher mortality. The survivors' group had an average CPB time of 70 ± 27 minutes while the non-survivors group 88.8 ± 25.4 minutes (P<0.001). Cross-clamp time in the survivors was 55.5 ± 20 minutes, while 64.9 ± 16 minutes in the non-survivors (P=0.014). Using multivariate logistic regression, CPB time is associated with death (Pearson's chi square= 0.0056). CPB time over 75 minutes presents an increased risk of death of 3.2 times (CI 95%: 1.3-7.9) over those with CPB time < 75 minutes. Post-operative variables associated with increased death rates: mechanical ventilation > 12 hours (P<0.001); ICU stay (P=0.033); re-exploration (P=0.001); inotropic support > 48 hours (P<0.001); use of blood components (P<0.001).

CONCLUSION

Overall mortality justifies the interventions. CPB time greater than 75 minutes, mechanical ventilation over 12 hours, length of ICU stay, need for reoperation, inotropic drug support over 48 hours, and use of blood components are associated with a higher mortality rate.