Clinical Application of Fractional Flow Reserve-Guided Percutaneous Coronary Intervention for Stable Coronary Artery Disease

The guiding value of hybrid resting full-cycle ratio and fractional flow reserve strategy for percutaneous coronary intervention in a Chinese real-world cohort with non-ST elevation acute coronary syndrome

Objective

The study aimed to assess the correlation and agreement between resting full-cycle ratio (RFR) and fractional flow reserve (FFR), and evaluate the guiding value of a hybrid RFR-FFR strategy for percutaneous coronary intervention (PCI) in a Chinese real-world cohort with non-ST elevation acute coronary syndrome (NSTE-ACS).

Materials and methods

A total of 109 patients with NSTE-ACS (149 diseased vessels), who underwent an invasive physiological assessment in Cangzhou Central Hospital, Hebei Medical University, were prospectively enrolled from September 2021 to May 2022. FFR ≤ 0.80 was used as the gold standard for coronary artery functional ischemia. We utilized the Pearson correlation and Bland-Altman analysis to assess the correlation and agreement between RFR and FFR. The diagnostic value of RFR predicting FFR ≤ 0.80 was evaluated in accordance with the receiver operating characteristic (ROC) curve. The hybrid RFR-FFR strategy, which was established according to determining the “gray zone” of RFR (FFR was further assessed using vasodilators only for diseased vessels in the “gray zone”), needed to afford over 95% global agreement with the FFR-only strategy.

Results

Resting full-cycle ratio was significantly linearly linked with FFR (R² = 0.636, P < 0.001). The accuracy, specificity, and sensitivity for RFR ≤ 0.89 predicting FFR ≤ 0.80 were 81.2, 70.8, and 86.1%, respectively. The area under the ROC curve for RFR predicting FFR ≤ 0.80 was 0.881 (P < 0.001), and the cutoff value was 0.90. The “gray zone” of RFR was 0.85–0.93. The positive and negative predictive values of the hybrid RFR-FFR strategy were 0.95 and 0.93, respectively. The hybrid RFR-FFR strategy exhibited an agreement of 96.0% with FFR and obviated the need for a vasodilator by 60.4%.

Conclusion

Resting full-cycle ratio and FFR have high correlation and consistency. The hybrid RFR-FFR strategy highlights considerably enhanced agreement with the FFR-only strategy, whilst making the requirement of vasodilator administration less than a half.

Functional Evaluation of Intermediate Coronary Lesions with Integrated Computed Tomography Angiography and Invasive Angiography in Patients with Stable Coronary Artery Disease

Background and objectives

The hemodynamic evaluation of coronary stenoses undergoes a transition from wire-based invasive measurements to image-based computational assessments. However, fractional flow reserve (FFR) values derived from coronary CT angiography (CCTA) and angiography-based quantitative flow ratio have certain limitations in accuracy and efficiency, preventing their widespread use in routine practice. Hence, we aimed to investigate the diagnostic performance of FFR derived from the integration of CCTA and invasive angiography (FFR_CT-angio) with artificial intelligence assistance in patients with stable coronary artery disease (CAD).

Methods

Forty stable CAD patients with 67 target vessels (50%-90% diameter stenosis) were included in this single-center retrospective study. All patients underwent CCTA followed by coronary angiography with FFR measurement within 30 days. Both CCTA and angiographic images were combined to generate a three-dimensional reconstruction of the coronary arteries using artificial intelligence. Subsequently, functional assessment was performed through a deep learning algorithm. FFR was used as the reference.

Results

FFR_CT-angio values were significantly correlated with FFR values (r = 0.81, P < 0.001, Spearman analysis). Per-vessel diagnostic accuracy of FFR_CT-angio was 92.54%. Sensitivity and specificity in identifying ischemic lesions were 100% and 88.10%, respectively. Positive predictive value and negative predictive value were 83.33% and 100%, respectively. Moreover, the diagnostic performance of FFR_CT-angio was satisfactory in different target vessels and different segment lesions.

Conclusions

FFR_CT-angio exhibits excellent diagnostic performance of identifying ischemic lesions in patients with stable CAD. Combining CCTA and angiographic imaging, FFR_CT-angio may represent an effective and practical alternative to invasive FFR in selected patients.