Diagnostic Performance of Non-Hyperemic Pressure Ratios Versus Fractional Flow Reserve Stratified by Coronary Artery:...

In the assessment of coronary physiology, non-hyperemic pressure ratios (NHPRs) provide an alternative to fractional flow reserve (FFR) without the need for hyperemic agents, reducing procedural time, side effects, and costs. However, it remains unclear whether NHPRs have similar diagnostic performance in the different coronary arteries. This study evaluates the diagnostic performance of NHPRs compared with FFR, stratified by coronary artery, in stable patients with coronary artery disease.

We conducted a systematic review and individual patient-level data meta-analysis from prospective studies involving patients with intermediate to severe coronary stenosis who underwent physiological assessment with NHPRs and FFR. NHPRs included resting full-cycle ratio or instantaneous wave-free ratio (iFR). The diagnostic performance of NHPRs was calculated using a threshold of ≤0.89 for NHPRs with FFR ≤0.80 as the reference and by stratifying between the left anterior descending artery (LAD) and non-LAD vessels.

A total of 2120 paired FFR and NHPRs (1257 resting full-cycle ratio, 863 iFR) measurements were analyzed. The LAD artery was the interrogated vessel in 67% of cases, the left circumflex artery in 15%, and the right coronary artery in 17%. The mean NHPR and FFR values were 0.80±0.17 and 0.71±0.14, respectively. The overall sensitivity, specificity, and accuracy of NHPRs were 82%, 86%, and 83%. In non-LAD vessels, NHPRs had significantly lower sensitivity and accuracy, but higher specificity compared with LAD (69% versus 87%, 76% versus 86%, and 91% versus 81%, respectively, P<0.001 for all). The optimal NHPRs cutoff for detecting significant lesions differed between LAD (≤0.88) and non-LAD (≤0.92).

NHPRs demonstrated lower diagnostic performance in non-LAD vessels compared with the LAD. These results underscore the need for vessel-specific interpretation of NHPR measurements.