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

BACKGROUND

Cardiac 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 (FFR) analysis provides prognostic information is unknown. This study aimed to assess the prognostic value of FFR for predicting major adverse cardiac events (MACE) and all-cause mortality in kidney transplant candidates.

METHODS

Among 553 consecutive kidney transplant candidates, 340 CCTA scans (61%) were evaluated with FFR analysis. Patients were categorized into groups based on lowest distal FFR; normal >0.80, intermediate 0.80-0.76, and low ≤0.75. In patients with ≥50% stenosis, a lesion-specific FFR 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.

RESULTS

Median 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 FFR ≤0.75 compared to patients with distal FFR >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 FFR >0.80 had a HR for MACE of 1.5 (95%CI: 0.4-4.8), p ​= ​0.55 while patients with lesion-specific FFR ≤0.80 had a HR of 6.0 (95%CI: 2.5-14.4), p ​< ​0.01. Abnormal FFR values were not associated with increased mortality.

CONCLUSION

In kidney transplant candidates, abnormal FFR values were associated with increased MACE but not mortality. Use of FFR may improve cardiac evaluation prior to transplantation.