Prognostic Value of Risk Factors, Calcium Score, Coronary CTA, Myocardial Perfusion Imaging, and Invasive Coronary Angiography in Kidney Transplantation Candidates

Abstract

Objectives: This study sought to perform a prospective head-to-head comparison of the predictive value of clinical risk factors and a variety of cardiac imaging modalities including coronary artery calcium score (CACS), coronary computed tomography angiography (CTA), single-photon emission computed tomography (SPECT), and invasive coronary angiography (ICA) on major adverse cardiac events (MACE) and all-cause mortality in kidney transplantation candidates.

Background: Current guidelines recommend screening for coronary artery disease in kidney transplantation candidates. Furthermore, noninvasive stress imaging is recommended in current guidelines, despite its low diagnostic accuracy and uncertain prognostic value.

Methods: The study prospectively evaluated 154 patients referred for kidney transplantation. All patients underwent CACS, coronary CTA, SPECT, and ICA testing. The clinical endpoints were extracted from patients' interviews, patients' records, and registries.

Results: The mean follow-up time was 3.7 years. In total, 27 (17.5%) patients experienced MACE, and 31 (20.1%) patients died during follow-up. In a time-to-event analysis, both risk factors and CACS significantly predicted death, but only CACS predicted MACE. Combining risk factors with CACS identified a very-low-risk cohort with a MACE event rate of 2.1%, and a 1.0% mortality rate per year. Of the diagnostic modalities, coronary CTA and ICA significantly predicted MACE, but only coronary CTA predicted death. In contrast, SPECT predicted neither MACE nor death.

Conclusions: Compared with traditional risk factors and other cardiac imaging modalities, CACS and coronary CTA seem superior for risk stratification in kidney transplant candidates. Applying a combination of risk factors and CACS and subsequently coronary CTA seems to be the most appropriate strategy. (Angiographic CT of Renal Transplantation Candidate Study [ACToR]; NCT01344434).

Keywords: coronary angiography; coronary artery calcium score; coronary computed tomography angiography; renal transplantation; single-photon emission computed tomography.