Background: Cardiac evaluation before kidney transplantation is recommended, but no unequivocal screening strategy has yet been identified. We investigated if coronary artery calcium score (CACS) can replace cardiovascular risk factor assessment in selection of kidney transplantation candidates for cardiac evaluation and the choice of noninvasive modality for diagnosing obstructive coronary artery disease (CAD).
Methods: We conducted a prospective study of 167 patients referred for pretransplantation cardiac evaluation. Patients underwent risk factor assessment, CACS, coronary computed tomography angiography (CCTA), single-photon emission computed tomography (SPECT), and invasive coronary angiography. In total, 138 patients completed all diagnostic tests.
Results: In patients with CAD (22%), the number of risk factors and CACS score were higher than that in patients without CAD. The accuracy evaluated by the receiver-operating characteristic curve was higher for CACS than for risk factors, 0.85 versus 0.71 (P = 0.01). Adding CACS to the risk factor increased correct categorical net reclassification (0.58, P < 0.0001). Combining risk factors (≥3) with SPECT to identify patients with obstructive CAD resulted in less sensitivity (47% vs 80%) and higher specificity (94% vs 74%), compared with CCTA. In patients with low CACS (<400), SPECT had a lower sensitivity than CCTA (60% versus 80%) but the same specificity (80%). In patients with high CACS (≥400), SPECT had lower sensitivity than CCTA (50% vs 100%) and higher specificity (88% vs 8%).
Conclusions: In kidney transplantation candidates, CACS outperformed risk factor assessment for predicting obstructive CAD and is a better tool for selecting patients and guiding the choice of noninvasive diagnostic modality in CAD.
Trial registration: ClinicalTrials.gov NCT01344434.