Association between post-procedural and long-term functional outcomes of jailed side branches in stented coronary bifurcation lesions assessed with side-branch murray law-based quantitative flow ratio

Abstract

Abstract Background In coronary bifurcation lesions treated with percutaneous coronary intervention (PCI) using a 1-stent strategy, the occurrence of side branch (SB) compromise may lead to long-term myocardial ischemia in the SB territory. Murray law-based quantitative flow ratio (μQFR) is a novel angiography-based approach estimating fractional flow reserve from a single angiographic view, and thus more feasible to assess SB compromise in routine practice. However, its association with long-term SB coronary blood flow remained unknown. Aim To explore the association between post-procedural SB μQFR and long term SB coronary blood flow in non-left main (LM) coronary bifurcation lesions receiving 1-stent strategy. Methods A total of 146 patients with 313 non-LM bifurcation lesions receiving 1-stent strategy with drug-eluting stents was included in this retrospective study. These lesions had post-procedural Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 in SBs, and documented angiographic images of index procedure and 6- to 24-month angiographic follow-up. The post-procedural SB μQFR was calculated. Long-term SB coronary blood flow was quantified with the TIMI grading system using angiograms acquired at angiographic follow-up. Results At follow-up, 8 (2.6%), 16 (5.1%), 61 (19.5%), and 228 (72.8%) SBs had a TIMI flow grade of 0, 1, 2, and 3, respectively. The incidences of SB TIMI flow grade <2 and <3 at follow-up both tended to decrease across the tertiles of post-procedural SB μQFR (TIMI flow grade <2: P=0.086; TIMI flow grade <3: P=0.052). In the multivariable logistic regression models, post-procedural SB μQFR was independently associated with SB TIMI flow grade <2 and <3 at follow-up, respectively (all P<0.05). The receiver operating characteristic curve analyses indicated that the area under the curve of post-procedural SB μQFR to identify SB TIMI flow grade <2 at follow-up was 0.6673 (95% CI, 0.5610-0.7737; P=0.0064), and the QFR limits to yield specificity and sensitivity >80% were 0.79 and 0.90, respectively. Conclusions Post-procedural SB μQFR in non-LM bifurcation stenoses was independently associated with impaired long-term SB coronary blood flow. Further investigations should focus on whether PCI optimization based on μQFR may contribute to improve SB flow in the long term.