For patients with renal failure kidney transplantation (KTx) confers improved quality and length of life. The survival benefit from KTx is limited by death from cardiovascular (CV) causes. The ASTS/AST recently endorsed an American Heart Association (AHA) statement on CV disease evaluation in KTx candidates. The guidance states that patients asymptomatic of coronary artery disease (CAD) should undergo non-invasive stress testing based on the presence of risk factors such as diabetes (DM), Previous cardiovascular disease, duration of renal replacement therapy (RRT) >12 months, left ventricular hypertrophy (LVH), age >60 years, smoking, hypertension (HTN) and dyslipidaemia. We examined a large cohort of asymptomatic patients, without prior CAD to devise a simple risk score and compared this against the AHA statement.
200 consecutive KTx candidates (135M:65F; age 53.8±11 yrs; 69% HD, 14% PD, 16% Predialysis, 2% Failing KTx; duration of RRT 30.7 ±53.6 Mth,;43% diabetic; 56% current or ex-smokers) underwent coronary angiography (CA) between 2000-2012. A Cox model of patient survival was constructed using AHA risk factors (except LVH and including ethnicity and gender). Only age, DM and current smoker status were significant factors. A Kaplan-Meier survival analysis showed age <45 years conferred a significant survival advantage (p<0.05). The Cox model was repeated with three risk factors (age >45, current smoker, DM) to establish the relative contributions of each (ExpB 3.6 (p=0.006), 2.2 (p=0.014), 2.1 (p=0.047) respectively). A risk score was given to each patient with 2 points each awarded to current smoker and DM and 3 points for age >45 years. Patients were categorized as low risk (≤2), medium risk (3-4) or high risk (≥5).
Angiographically significant CAD correlated with increasing risk (12.2%, 18.6%, 34.7%, p=0.01). Overall patient survival was worse with increasing risk (89%, 80% and 69% at 5 years, p=0.005). Across all risk groups KTx recipients had improved survival (100 v 68%, 92 v 68%, 90 v 57% at 5 years). Patient survival was poor in high risk patients who were revascularised but not transplanted (n=16, p=0.07). Insufficient numbers of patients were revascularised and transplanted to comment on differences in survival.
In Cox modelling this simple risk score outperformed both the AHA model and CA findings as predictors of death. We suggest that this simple risk score has the potential to streamline CAD assessment and expedite transplantation.
To cite this abstract in AMA style:Lawrence C, Cruickshank S, Manoj A, Mathavakkannan S, Chandna S, Fluck S, Farrington K. Simple Cardiovascular Risk Score Predicts Mortality in Kidney Transplant Candidates, A [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/simple-cardiovascular-risk-score-predicts-mortality-in-kidney-transplant-candidates-a/. Accessed May 17, 2021.
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