Evaluation of coronary artery disease using computed tomography angiography and perfusion in patients with end-stage renal disease

Abstract

Patients with end-stage renal disease (ESRD) have a high incidence of atherosclerotic coronary artery disease. Cardiovascular disease is the main cause of morbidity and mortality in this population, being responsible for up to fifty percent of all deaths. Noninvasive tests usually performed in the general population such as dobutamine stress echocardiography and radionuclide myocardial perfusion imaging have shown to be inaccurate for the diagnosis of coronary artery disease in patients with ESRD. Therefore, invasive coronary angiography is usually required in patients at high risk of cardiovascular disease during assessment for renal transplantation.The purpose of this research project is to assess the performance of combined coronary computed tomography (CT) angiography and stress myocardial CT perfusion in the diagnosis of coronary artery disease. This technology has not yet been studied in patients with ESRD, but has showed excellent accuracy in the general population. In patients with ESRD, vascular calcification usually impairs adequate assessment of the degree of obstructive plaques, limiting the diagnostic accuracy of conventional coronary CT angiography. The result of the perfusion part of the test might help to differentiate obstructive from non-obstructive plaques and increase the diagnostic accuracy of the method. In the present protocol, eighty patients with ESRD will be evaluated for coronary artery disease as a preparation for renal transplantation. Inclusion criteria will be:- ESRD with a plan to undergo renal transplantation and- at least one of the following: age e 50 years, diabetes mellitus, angina, prior myocardial infarction or stroke, peripheral artery disease or left ventricular dysfunction (ejection fraction d 50%).Exclusion criteria will be: age < 18 years, acute coronary syndromes in the 3 months prior to assessment, previous percutaneous coronary intervention or coronary artery bypass surgery and refusal from the patient to participate in the study.All patients will undergo clinical and laboratory evaluation (including high-sensitive troponin), transthoracic echocardiography, radionuclide myocardial perfusion imaging and invasive coronary angiography as a part of their usual assessment prior to inclusion in renal transplant waiting list. As a part of the protocol, combined coronary CT angiography and myocardial CT perfusion will be performed prior the invasive angiography. After the evaluation, patients will be treated according to current guidelines for coronary artery disease and will be followed in the unit of coronary artery disease at 1, 3, 6 and 12 months in the first year, and every six moths thereafter.The diagnostic accuracy for obstructive coronary artery disease of CT angiography and perfusion will be compared to the results of invasive angiography (gold-standard), by calculating sensitivity, specificity, positive and negative predictive values. It will also be compared to the performance of radionuclide myocardial perfusion imaging. The ability of the coronary CT angiography and perfusion in predicting clinical events in this group of patients will also be determined during follow-up.We expect that combined coronary CT angiography and stress myocardial CT perfusion to be a noninvasive diagnostic test with high sensitivity and specificity in the evaluation for coronary artery disease in patients with ESRD, which could possibly reduce the number of unnecessary invasive coronary angiographies, increasing patient's safety and reducing unnecessary costs. (AU)