The influence of pre-operative electrocardiographic abnormalities and cardiovascular risk factors on patient and graft survival following renal transplantation

Abstract

Premature cardiovascular disease (CVD) is the leading cause of mortality and of graft loss in renal transplant recipients. However, the pattern of cardiovascular risk factors (specifically modifiable risk factors) is not well established and may be different from the general population. In this study we investigated the importance of electrocardiographic abnormalities and conventional cardiovascular risk factors present at the time of first renal transplantation in a longitudinal follow-up study of 515 patients. Overall, 45.8% were cigarette smokers, 13.0% were diabetic, 75.1% had "hypertension", 12.2% had symptoms of angina pectoris and 9.1% had a past history of myocardial infarction or stroke. Two thirds of ECG tracings were abnormal. 58.7% of men and 37.5% of women had left ventricular hypertrophy (LVH). Overall, 28.2% had simple LVH, 20.5% had LVH with repolarisation changes ('strain'). 434 patients had complete data for multivariate analyses of patient and graft survival. A Cox multivariate analysis of patient survival (patients whose graft failed were censored in the analysis) identified: age (hazard ratio 1.03/year), diabetes (2.72), smoking (1.81) and family history of premature CVD (2.17) as independent risk factors for patient survival. An abnormal ECG was also independently associated with outcome, with the exception of isolated left ventricular hypertrophy. Left ventricular hypertrophy with strain, or ischaemic changes were associated with adverse outcome with a hazard ratio of 1.96 and 3.30 respectively. A similar analysis of the determinants of graft survival (patients who died with a functioning graft were censored in the analysis) identified: acute rejection (hazard ratio 2.38), cigarette smoking (1.48) and age (1.04/year) as independent predictors of graft failure. These data demonstrate a high prevalence of ECG abnormalities and CV risk factors in renal transplant recipients. Moreover, ECG abnormalities and "conventional" cardiovascular risk factors are associated with poor graft and patient outcome and represent potentially remediable risk factors for renal transplant recipients.