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Outcomes of quantitative flow ratio–based functional incomplete revascularization after coronary artery bypass grafting surgery

Read at the 103rd Annual Meeting of The American Association for Thoracic Surgery, Los Angeles, California, May 6-9, 2023.
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Abstract

Objective

Quantitative flow ratio is a novel functional assessment tool of coronary diseases. Whether quantitative flow ratio could improve the outcomes of coronary artery bypass grafting is undetermined. This study aimed to investigate the association between the quantitative flow ratio based functional incomplete revascularization and the outcomes after coronary artery bypass grafting surgery.

Methods

The quantitative flow ratio assessment was retrospectively performed in patients undergoing coronary artery bypass grafting surgery in the PATENCY trial. The anatomic complete revascularization denoted revascularizing each territory with stenosis greater than 50% evaluated by angiography. The functional complete revascularization was defined as grafting all vessels with a quantitative flow ratio 0.80 or less. The primary end point was the 12-month composite major adverse cardiac or cerebral vascular events.

Results

A total of 2024 patients with available quantitative flow ratio values were included. Functional complete revascularization was achieved in 1846 patients (91.2%), and 1600 received anatomic complete revascularization (79.1%). Both the functional incomplete revascularization and anatomic incomplete revascularization groups were associated with significantly increased risks of 12-month major adverse cardiac or cerebral vascular events (functional: hazard ratio, 2.91; 95% confidence interval, 1.56 to 5.43; P = .001; anatomic: hazard ratio, 2.82; 95% confidence interval, 1.54 to 5.16; P = .001). Additionally, for the subgroup of patients (n = 246) receiving anatomic incomplete revascularization but judged as functional complete revascularization by quantitative flow ratio, the risk of the 12-month major adverse cardiac or cerebral vascular events was not significantly increased (adjusted hazard ratio, 1.36; 95% confidence interval, 0.71-2.60; P = .35).

Conclusions

Both the functional incomplete revascularization and anatomic incomplete revascularization were associated with increased risks of 12-month major adverse cardiac or cerebral vascular events after coronary artery bypass grafting surgery. The quantitative flow ratio can serve as a supplementary tool for the decision-making of surgical revascularization.

Section snippets

Study Participants

A post hoc analysis of the Graft Patency Between No-touch Vein Harvesting Technique and Conventional Approach in Coronary Artery Bypass Graft Surgery (PATENCY) trial was conducted. The PATENCY was a multicenter, open-labeled, randomized control trial that enrolled 2655 patients undergoing isolated CABG from 7 hospitals in China between 2017 and 2019.9,10 The study was registered at ClinicalTrials.gov (identifier: NCT03126409). The protocol of the trial was approved by the Institutional Review

Patient Characteristics

Of the 2655 participants enrolled in the PATENCY study, 17 patients were excluded for not receiving surgery. A total of 614 patients of the remaining 2638 were excluded for incomplete QFR analysis (393 with angiogram unreadable or loss of image, and 220 due to 1 or more vessels not analyzable by QFR). Detailed reasons for exclusion of QFR assessment are shown in Figure 1. Comparison of the baseline characteristics and outcomes between the include and excluded patients are shown in Table E1,

Discussion

The main findings of the present post hoc analysis showed that both functional and anatomic ICR were associated with significantly higher risks of composite MACCE at 12 months of follow-up. In the anatomic ICR subgroup, this association became insignificant when judged as CR by QFR. The rates of all-cause mortality were of no significant difference between the CR and ICR groups, whether by the assessment of QFR or anatomy.

Our findings reemphasized the clinical benefit of achieving CR in

Conclusions

In this retrospective analysis of patients undergoing CABG surgery, both QFR judged functional ICR and anatomic ICR significantly increased the risk of MACCE at 12-month follow-up. However, when the revascularization was considered anatomically incomplete but judged as functionally complete by the QFR, the association was not statistically significant. Compared with anatomic judgment by angiography alone, the QFR can be considered a supplementary tool for decision-making of revascularization in

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  • Institutional Review Board Date and Number: October 25, 2016. Approval No: 2016-827.

    Informed consent was obtained from all participants.

    M.T., B.X., and L.C. contributed equally to this article.

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