Long term clinical and functional assessment following Left Main coronary artery percutaneous intervention: insights on Quantitative Flow Ratio (QFR).

Background Several studies comparing single and double stenting techniques of Percutaneous Coronary Intervention (PCI) on Left Main (LM) report contradictory results in terms of incidence of periprocedural and long-term adverse events. Thus, uncertainties remain on the best stenting technique for LM coronary artery lesions. The Quantitative Flow Ratio (QFR) is a coronary angiography-based tool recently introduced in clinical practice to obtain details on the on physiologic status of a coronary vessel through the analysis of two angiographic projections. The post-PCI QFR value has been demonstrated as a potential predictor of adverse events although no data are to date available in the setting of LM PCI. Objectives (1) To investigate the impact of LM 1-stent vs 2-stent technique on vessel-oriented composite endpoint (VOCE) defined as the composite of vessel-related cardiovascular death, vessel-related MI, and ischemia-driven target vessel revascularization (TVR) at 12-36-months FU. (2) To investigate the impact of different double-stent techniques currently used in clinical practice (Culotte, T TAP, Mini Crush) on VOCE at 12-36m follow up (3) To explore the technical feasibility of QFR on LM and investigate the relationship between post-PCI QFR and VOCE incidence up to 12-36-months follow up, exploring the potential value of QFR as a predictor of patient’s outcome. Methods All patients successfully treated with DES on the LM between 1/2016 and 12/2018 were included in this retrospective, multi-center registry(QUARTILE:QUantitAtive flow RaTIo on Left main). FU was obtained by clinical visit and/or through telephone contact. Angiographic follow-up was also collected when available. Endpoints of interest were a vessel-oriented composite endpoint. Computation of QFR was computed after the PCI evaluating last angiographic projections acquired. Results A total of 234 patients undergoing PCI with DES on LM were included. Baseline and periprocedural main features were similar among the two groups. The average length of the FU was 19 ± 15,9 months; angiographic FU details were available in 110 patients (47%). The number of VOCEs in the study court was 57(24,3%): 18(26,0%) occurred in the 2-stent group, while 39(23,6%) in the 1-stent group. TLRs occurred in 21 patients (9%), 13% in the 2-stent group and 7.3% in the 1-stent. Death occurred in 15(6.4%) case, namely 4(5.8%) treated with 2-stent and 11(6.7%) treated with 1-stent technique. There were no statistically significant differences between the incidence of VOCE and it’s composite in the 1- or 2-stent treatment groups. The incidence of VOCE and it’s composites were not differently stratified in the three groups stratified by type of double-stent technique. The number of patients in whom QFR was performed was 39(47,0%). Within this subgroup the VOCE was 14(35.8%), of which 10(25.6%) TLR, 4 TVR(10.2%) and 0 deaths. ROC curves were computed reporting a poor overall predictive value: AUC of the QFR-ML curve 0.44(0.25 – 0.63), QFR-VESSEL 0.51(0.32 –0.69). Conclusions 1)The use of DES in PCI treatment of ML has shown in our study population good immediate and long-term results, in line with international case series. 2)There were no significant differences between 1- and 2-stent strategies. 3)A preliminary analysis on QFR post LM PCI as potential predictive index of long-term outcome demonstrated many limitations, highlighting that, in many cases the analysis was not technically feasible.