Assessing cardiovascular risk in chronic kidney disease patients prior to kidney transplantation: clinical usefulness of a standardised cardiovascular assessment protocol

Abstract

Background: Despite pre-kidney-transplant cardiovascular (CV) assessment being routine care to minimise perioperative risk, the utility of such assessment is not well established. The study reviewed the evaluation and outcome of a standardised CV assessment protocol.

Methods: Data were analysed for 231 patients (age 53.4 ± 12.9 years, diabetes 34.6%) referred for kidney transplantation between 1/2/2012-31/12/2014. One hundred forty-three patients were high-risk (age > 60 years, diabetes, CV disease, heart failure, peripheral vascular disease) and offered dobutamine stress echocardiography (DSE); 88 patients were low-risk and offered ECG and echocardiography with/without exercise treadmill test.

Results: At the end of follow-up (579 ± 289 days), 35 patients underwent kidney transplantation and 50 were active on the waitlist. There were 24 events (CV or death), none were perioperative. One hundred fifteen patients had DSE with proportionally more events in DSE-positive compared to DSE-negative patients (6/34 vs. 7/81, p = 0.164). In 42 patients who underwent coronary angiography due to a positive DSE or ischaemic heart disease symptoms, 13 (31%) had events, 6 were suspended, 11 removed from waitlist, 3 wait-listed, 1 transplanted and 17 still undergoing assessment. Patients with significant coronary artery disease requiring intervention had poorer event-free survival compared to those without intervention (56% vs. 83% at 2 years, p = 0.044). However, the association became non-significant after correction for CV risk factors (HR = 3.17, 95% CI 0.51-19.59, p = 0.215).

Conclusions: The stratified CV risk assessment protocol using DSE in all high-risk patients was effective in identifying patients with coronary artery disease. The coronary angiograms identified the event-prone patients effectively but coronary interventions were not associated with improved survival.

Keywords: Cardiovascular disease; Cardiovascular events; Chronic kidney disease; Coronary angiography; Dobutamine stress echocardiography; Kidney transplantation.

Fig. 1

Cardiovascular risk stratification protocol. DM, Diabetes Mellitus; IHD, Ischaemic Heart Disease; CCF, Congestive Cardiac Failure; PVD, Peripheral Vascular Disease; TTE, Transthoracic Echocardiography; ETT, Exercise Treadmill Test; DSE, Dobutamine Stress Echocardiography

Fig. 2

Risk stratification and subsequent investigations for potential kidney transplant recipients belonging to low-risk and high-risk groups. N = number of patients. ^*1 patient awaiting TTE; ^†5 patients had DSE without ETT or TTE (unable to perform ETT); ˆ29 patients deemed unsuitable for transplantation and discontinued further cardiac workup; ˆˆETT and TTE performed for other reasons outside of protocol; ^**2 patients with positive DSE yet to complete CA; ^††1 patient had a treadmill exercise echocardiography as DSE could not be performed; TTE, Transthoracic Echocardiography; ETT, Exercise Treadmill Test; DSE, Dobutamine Stress Echocardiography; CA, Coronary Angiography

Fig. 3

Event rates in patients with and without a positive dobutamine stress echocardiography test. DSE positive patients had more events compared to DSE negative patients (log rank p = 0.164). Events were defined as the occurrence after referral for transplant evaluation of a non-fatal cardiovascular event (myocardial infarction, unstable angina, congestive heart failure, stroke, transient ischaemic attack and amputation) and sudden cardiac death or death from any cause. DSE, Dobutamine Stress Echocardiography; CV, Cardiovascular

Fig. 4

Event rates during follow-up in patients having had coronary angiography - comparing those requiring or not requiring PCI or CABG. Patients requiring PCI or CABG were more likely to have events (log rank p = 0.044). Events were defined as the occurrence after referral for transplant evaluation of a non-fatal cardiovascular event (myocardial infarction, unstable angina, congestive heart failure, stroke, transient ischaemic attack and amputation) and sudden cardiac death or death from any cause. PCI, Percutaneous Coronary Intervention; CABG, Coronary Artery Bypass Graft