Feasibility of Quantitative Flow Ratio Virtual Stenting for Guidance of Serial Coronary Lesions Intervention

Abstract

Background Coronary physiology measurement in serial coronary lesions with multiple stenoses is challenging. Therefore, we evaluated the feasibility of Murray fractal law‐based quantitative flow ratio (μQFR) virtual stenting for guidance of serial coronary lesions intervention. Methods and Results Patients who underwent elective coronary angiography and had 2 serial de novo coronary lesions of 30% to 90% diameter stenosis by visual estimation were prospectively enrolled. μQFR and fractional flow reserve (FFR) were assessed after coronary angiography. In vessels with an FFR ≤0.80, the lesion with the larger pressure gradient was considered to be the primary lesion and treated firstly, followed by FFR measurement. The second lesion was stented when FFR ≤0.80. All μQFR and predicted μQFR after stenting were calculated from diagnostic coronary angiography before interventions, with the analysts masked to the FFR data. A total of 54 patients with 61 target vessels were interrogated. Percutaneous coronary intervention was performed in 44 vessels with FFR ≤0.80. After stenting the primary lesions, 14 nonprimary lesions had FFR ≤0.80 and a second drug‐eluting stent was implanted. There was excellent correlation ( r =0.97, P <0.001) and good agreement (mean difference: 0.00±0.03) between baseline μQFR and FFR in identifying flow‐limiting lesions. Per‐vessel diagnostic accuracy of μQFR on de novo lesions was 96.7% (95% CI, 88.7%–99.6%). μQFR and FFR are highly consistent (93.2%) in identifying the primary lesion requiring revascularization. After stenting the primary lesions, per‐vessel diagnostic accuracy of predicted μQFR for identifying the significance of the nonprimary lesion was 90.9%. Predicted residual μQFR with virtual stenting was higher than final FFR (mean difference: 0.05±0.06). Conclusions In vessels with serial coronary lesions, virtual stenting by μQFR can identify the primary flow‐limiting lesion for revascularization.

Predictive value of the inconsistency between the residual and post-PCI QFR for prognosis in PCI patients

“…Previous landmark studies have demonstrated the instrumental value of the QFR in guiding the PCI procedure and further improving the clinical prognosis ( 10 – 12 ). The residual QFR is a predicted QFR value based on coronary angiographic imaging that simulates successful stent implantation in the culprit lesion, correlates well with the post-PCI FFR and QFR, and predicts the occurrence of adverse events after revascularization ( 13 , 14 , 16 , 22 ). A retrospective analysis of the PANDA III trial showed that the predicted clinical outcome of residual QFR-guided PCI was superior to that of angio-guided PCI ( 15 , 23 ).…”

“…Based on the residual QFR, a cardiologist can identify the major lesion from a functional perspective, further optimizing the PCI strategy. The residual QFR-guided PCI strategy was superior to angiographic guidance in reducing the 2-year incidence of target vessel failure (TVF) ( 15 , 16 ). However, research into the predictive value of the residual QFR for adverse events is limited, particularly in patients whose residual QFR does not match their post-PCI QFR.…”

Quantitative Flow Ratio and Virtual Percutaneous Coronary Intervention for Serial Coronary Stenoses: Attractive Technology, But Still Crawling

“…In summary, the study by Guan and colleagues 14 is informative and sheds light for further research. Once streamlined, QFR may serve as a useful tool to supplement coronary angiography, but further studies are needed to establish its role in predicting residual FFR following PCI to help procedural planning as well as broadening the role of noninvasive tools to assess microvascular function.…”

“…In this issue of the Journal of the American Heart Association ( JAHA ), Guan and colleagues 14 report the results of a prospective study assessing the utility of uQFR to virtually plan PCI. Participants presented with 2 serial lesions that were visually estimated between 30% and 90% in the same epicardial vessel and separated by at least 10 mm of an angiographically‐looking normal segment.…”

“… 4 , 5 Notably, the same comment also applies to the paper by Guan and colleagues. 14 Given the lack of clinical outcomes assessment, it substantially limits the knowledge translation into daily clinical practice. Finally, while the adoption of less invasive approaches is welcome, pressure wire‐based measurements provide important diagnostic information for the workup of ischemia with nonobstructive coronary arteries (INOCA), providing evidence of impaired coronary microvascular function through impaired coronary flow reserve (<2.0) 19 or abnormal coronary microvascular resistance indices (such as indices index of microcirculatory resistance ≥25).…”