Peri-operative cardiac morbidity in kidney transplant recipients: Incidence and risk factors

Background: Renal transplant recipients are known to be at increased risk for developing cardiac disease. In both general and peripheral vascular surgery, pre-operative risk stratification (and intervention when indicated) has decreased the incidence of peri-operative cardiac complications. In this study, we set out to identify subsets of patients at high risk for peri-operative cardiac complications after a renal transplant. Methods: We retrospectively reviewed the records of 2694 adult renal transplants performed at the University of Minnesota between January 1, 1985 and December 31, 1998. We determined the incidence of perioperative (within 30 d post-transplant) cardiac complications, including myocardial infarction (MI). Risk factors for the development of these complications were determined by multivariate analysis. Results: We found 163 peri-operative cardiac complications, for an overall incidence of 6.1%. Specific cardiac complications included MI (n = 43, 1.6%), arrhythmia (n = 74, 2.7%), angina (n= 31, 1.2%), cardiac arrest (n = 13, 0.5%), and congestive heart failure (n = 2, 0.1%). By multivariate analysis, significant risk factors for any cardiac complication were age≥ 50 yr (relative risk (RR) = 3.0, p = 0.0001) and pretransplant cardiac disease (RR = 3.3, p = 0.0001). Not significant were diabetes mellitus (DM), cadaver donor source, pre-transplant dialysis, a history of smoking, and hypertension. Significant risk factors for perioperative MI were age ≥ 50 yr, pre-existing cardiac disease, and DM. Diabetic patients with pre-existing cardiac disease were at especially high risk for peri-operative cardiac events. Conclusions: Patients > 50 yr and those with pre-existing cardiac disease, especially if diabetic, are at significantly increased risk for developing peri-operative cardiac complications after a renal transplant. Such patients require aggressive pre-operative investigations, which may include coronary angiography, to decrease the risk of post-transplant complications.