Positron Emission Tomography Versus Coronary Angiography for Initial Cardiac Screening in Kidney Transplant Candidates: Waitlisting and Clinical Outcomes

BackgroundCardiac evaluation is an important component of kidney transplant evaluation, but the optimal initial testing approach remains uncertain. MethodsBecause the initial test was clinician-selected rather than randomized, this retrospective cohort study examined associations between the initial cardiac testing pathway (PET versus coronary angiography) and transplant listing status among 116 kidney transplant candidates (57 PET, 59 coronary angiography).Because many candidates had already been listed before the index cardiac test, binary analyses were interpreted as associations between clinician-selected testing pathways and listing status rather than posttesting effects on waitlisting.A test-date-anchored landmark analysis, restricted to candidates not yet listed for testing, was used to evaluate subsequent time to listing.Firth-penalized logistic regression and inverse probability of treatment weighting (IPTW) were performed as complementary analyses. ResultsKnown coronary artery disease (CAD) differed markedly by testing modality, consistent with confounding by indication and clinician-directed test selection.Overall, 99/116 patients (85.3%) were listed, with no statistically significant difference between groups.Because 31/57 (54.4%)PET patients and 24/59 (40.7%) angiography patients were already listed before testing, the unadjusted evaluation-to-listing timeline could not be attributed to testing modality.The landmark analysis included 58 patients not yet listed at testing, with 55 complete cases in the adjusted model; coronary angiography versus PET was not significantly associated with subsequent time to listing (adjusted hazard ratio [HR], 1.76; 95% CI, 0.76-4.07).In an exploratory subgroup of patients without known CAD (n=30), the estimated rate of subsequent listing was higher with coronary angiography than with PET (HR, 2.58; 95% CI, 1.08-6.16);however, the small subgroup and wide confidence interval warrant caution, and this finding should not be interpreted as evidence of effect modification in the absence of a reproducible formal interaction test.The Firth model showed no significant association between testing pathway and listing status (OR, 1.56; 95% CI, 0.51-4.72),consistent with IPTW (OR, 1.62; 95% CI, 0.54-4.83).Only eight one-year major adverse cardiovascular events occurred, precluding conclusions regarding comparative cardiovascular safety. ConclusionsInitial cardiac testing was clinician-selected and strongly related to known CAD status; therefore, these findings primarily describe associations between clinically selected testing pathways rather than causal effects of interchangeable testing strategies.After accounting for temporal ordering, no statistically significant overall association between modality and subsequent time to listing was identified.The finding among patients without known CAD was exploratory and requires confirmation.Given the observational design, modest sample size, residual confounding, and limited number of cardiovascular events, these results do not establish the superiority or equivalent safety of either PET or coronary angiography.