Validation and comparison of non-hyperemic pressure reserve to fractional flow reserve for assessment of coronary artery stenosis: A real world study.

Background: The visual interpretation of an angiographic stenosis may not always reflect the physiological significance of a lesion. Fractional Flow Reserve (FFR) is a reliable index to assess the significance of a lesion during hyperemia. However, there are pitfalls that can lead to significant misinterpretation and adverse events.

Objective: This study sought to evaluate the accuracy and predictability of the non-hyperaemic pressure ratio (NHPR) without hyperemic stimuli, compared to hyperemic FFR.

Methods: We conducted a retrospective, multicenter study of 700 patients who underwent a pressure recording during coronary angiography using NHPR and FFR measurements. Receiver operator characteristic (ROC) curve was constructed. NHPR sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy test were calculated. The most accurate NHPR cutoff was determined.

Results: Of the 700 procedures, 449 cases were included. By ROC analysis, the optimal cut-point for NHPR was 0.93 to predict an FFR of ≤0.80 with an overall diagnostic accuracy of 78.84%. The sensitivity of this NHPR cutoff was 85.06%, specificity of 75.59%, PPV of 64.53% and a NPV of 90.65%. There was an overall accuracy of about 80% for predicting non-hyperemic index (FFR < 0.80) using a cutoff of NHPR ≤ 0.93.

Conclusions: The use of NHPR can be considered in certain clinical scenarios where adenosine is contraindicated or there are other challenges; with the knowledge that hyperemia might be necessary if there is any high clinical suspicion as it still remains the reference standard for diagnostic certainty.