Clinical implication of quantitative flow ratio to predict clinical events after drug-coated balloon angioplasty in patients with in-stent restenosis

Abstract

Background: The association between the quantitative flow ratio (QFR) and adverse events after drug-coated balloon (DCB) angioplasty for in-stent restenosis (ISR) lesions has not been investigated.

Hypothesis: Post-procedural QFR is related to adverse events in patients undergoing DCB angioplasty for ISR lesions.

Methods: This retrospective study included data from patients undergoing DCB angioplasty for drug-eluting stent (DES) ISR between January 2016 and February 2019. The QFR was measured at baseline and after DCB angioplasty. The endpoint was the vessel-oriented composite endpoint (VOCE), defined as a composite of cardiac death, vessel-related myocardial infarction, and ischemia-driven target vessel revascularization.

Results: Overall, 177 patients with 185 DES-ISR lesions were included. During 1-year follow-up, 27 VOCEs occurred in 26 patients. The area under curve (AUC) of the post-procedural QFR was statistically greater than that of the in-stent percent diameter stenosis (0.77, 95% confidence interval [CI] 0.67-0.87 vs. 0.64, 95% CI 0.53-0.75; p = .032). Final QFR cutoff of 0.94 has the best predictive accuracy for VOCE. A QFR > 0.94 was associated with a lower risk of VOCE compared to a QFR ≤ 0.94 (log-rank test, p < .0001). Survival analysis using the multivariable Cox model showed that a post-procedural QFR ≤ 0.94 was an independent predictor of 1-year VOCE (hazard ratio 6.53, 95% CI 2.70-15.8, p < .001).

Conclusions: A lower QFR value was associated with worse clinical outcomes at 1 year after DCB angioplasty for DES-ISR.

Keywords: drug-coated balloon; percutaneous coronary intervention; quantitative flow ratio.

FIGURE 1

Case example of reconstructed 3‐D QCA and measured QFR. QFR calculation was based on the 3D‐QCA reconstructed from two angiographic projections with angles ≥25 ° apart and 3D reconstruction of the interrogated vessel without its side branches was performed. (A) Pre‐procedural angiographic image shows a ISR lesion, and QFR was 0.70 (B) Final angiography showed minimal residual stenosis after DCB treatment, and QFR was 0.96. Red arrows indicate the target ISR lesion. DCB, drug‐coated balloon; ISR, in‐stent restenosis; QCA, quantitative coronary angiography; QFR, quantitative flow ratio

FIGURE 2

(A) Receiver operator characteristic curves for the VOCE. The red line corresponds to the QFR value (AUC 0.77, 95% CI 0.67–0.87) and the green line to the in‐stent %DS (AUC 0.64, 95% CI 0.53–0.75). (B) Kaplan–Meier curves of VOCE occurrence at 1‐year follow‐up according to the post‐procedural QFR. AUC, area under curve; CI, confidence interval; %DS, percent diameter stenosis; QFR, quantitative flow ratio; VOCE, vessel‐oriented composite endpoint