Prognostic value of computed tomography derived fractional flow reserve for predicting cardiac events and mortality in kidney transplant candidates

BackgroundCardiac screening using coronary computed tomography angiography (CCTA) in kidney transplant candidates before transplantation yields both diagnostic and prognostic information. Whether CT-derived fractional flow reserve (FFRCT) analysis provides prognostic information is unknown.This study aimed to assess the prognostic value of FFRCT for predicting major adverse cardiac events (MACE) and all-cause mortality in kidney transplant candidates.MethodsAmong 553 consecutive kidney transplant candidates, 340 CCTA scans (61%) were evaluated with FFRCT analysis. Patients were categorized into groups based on lowest distal FFRCT; normal >0.80, intermediate 0.80–0.76, and low ≤0.75. In patients with ≥50% stenosis, a lesion-specific FFRCT was defined as; normal >0.80 and abnormal ≤0.80.The primary endpoint was MACE (cardiac death, resuscitated cardiac arrest, myocardial infarction or revascularization). The secondary endpoint was all-cause mortality.ResultsMedian follow-up was 3.3 years [2.0–5.1]. MACE occurred in 28 patients (8.2%), 29 patients (8.5%) died.When adjusting for risk factors and transplantation during follow-up, MACE occurred more frequently in patients with distal FFRCT ≤0.75 compared to patients with distal FFRCT >0.80: Hazard Ratio (HR): 3.8 (95%CI: 1.5–9.7), p ​< ​0.01.In the lesion-specific analysis with <50% stenosis as reference, patients with lesion-specific FFRCT >0.80 had a HR for MACE of 1.5 (95%CI: 0.4–4.8), p ​= ​0.55 while patients with lesion-specific FFRCT ≤0.80 had a HR of 6.0 (95%CI: 2.5–14.4), p ​< ​0.01.Abnormal FFRCT values were not associated with increased mortality.ConclusionIn kidney transplant candidates, abnormal FFRCT values were associated with increased MACE but not mortality. Use of FFRCT may improve cardiac evaluation prior to transplantation.