Predictors and 3-year outcomes of compromised left circumflex coronary artery after left main crossover stenting

Correlation between LCX-QFR and clinical outcomes following a single-stent strategy for left main bifurcation lesions

Objective

The aim of this study was to investigate the quantitative flow ratio (QFR) outcomes in the left circumflex artery (LCX) following the placement of a crossover stent from the left main coronary artery (LM) to the left anterior descending artery (LAD) in LM bifurcation lesions. In addition, we sought to assess the relationship between these QFR results and clinical prognoses.

Background

The treatment approach for LM bifurcation lesions remains a topic of debate, with the LM-LAD single-stent technique being one possible option. QFR, a fractional flow reserve calculation method derived from angiography that does not require pressure guide wires, could serve as an alternative functional assessment of the LCX. This study aims to evaluate the clinical outcomes of postoperative LCX by utilizing QFR measurements, addressing a current gap in the relevant literature on this topic.

Methods

This study was a retrospective, single-center analysis of patients with LM bifurcation lesions who underwent percutaneous coronary intervention (PCI) guided by intravascular ultrasound. QFR values were derived from angiographies. The primary endpoint was the 1-year rate of major adverse cardiac events, defined as a composite of cardiovascular death, target bifurcation-related myocardial infarction (MI), or target bifurcation revascularization. The secondary clinical endpoint was defined as the persistence or recurrence of angina pectoris after PCI.

Results

We analyzed 91 patients from a total of 180 who were screened for LM bifurcation lesions. All patients completed the 1-year follow-up. The pre- and post-PCI QFR values were 0.89 ± 0.09 and 0.86 ± 0.11, respectively. Subgroup analysis showed that 74 patients were in the postoperative QFR ≥0.80 group, whereas 17 patients were in the QFR <0.80 group. In addition, 32 patients had a ΔQFR ≥0, and 58 patients had a ΔQFR <0. Nine patients (9.9%) achieved the primary endpoint, including one patient with non-ST elevation myocardial infarction who received revascularization in both the LM-LAD and LCX arteries. In addition, nine patients (9.9%) reported no substantial improvement in their chest pain symptoms. Post-LCX-QFR <0.8 was associated with a higher 1-year incidence of cardiovascular death or MI (P = 0.036). ΔQFR proved to be a robust predictor of the 1-year incidence of the primary endpoint, with an incidence of 15.3% in the ΔQFR ≥0 group compared to 0% in the ΔQFR <0 group (area under the curve: 0.822; 95% CI: 0.728-0.895, P < 0.001), especially when ΔQFR ≤-0.03.

Conclusions

After the LM-LAD single-stent strategy for LM bifurcation lesions, a ΔQFR of LCX ≤-0.03 was associated with a higher risk of 1-year main adverse cardiac events, indicating the superior prognostic value of the post-PCI physiological assessment.

A New Scoring System Predicting Side-Branch Occlusion in Patients Undergoing Left Main Bifurcation Intervention: The LM V-RESOLVE Score

BACKGROUND

The risk of side-branch (SB) occlusion is pivotal for decision making of stenting strategies during unprotected left main (LM) bifurcation percutaneous coronary intervention (PCI). Accordingly, this study aimed to develop a scoring system for predicting SB occlusion during unprotected LM bifurcation PCI.

METHODS

A total of 855 consecutive patients undergoing unprotected LM bifurcation PCI with provisional strategy at Fuwai Hospital from January 2014 to December 2016 were recruited. A prediction model was selected by means of all-subsets logistic regression, and a multivariable risk score (Left Main Visual Estimation for Risk Prediction of Side Branch Occlusion in Coronary Bifurcation Intervention [LM V-RESOLVE]) was then established with incremental weights attributed to each component variable based on its estimate coefficients. SB occlusion was defined as any decrease in Thrombolysis in Myocardial Infarction (TIMI) flow grade or absence of flow in SB after main vessel (MV) stenting.

RESULTS

SB occlusion occurred in 19 LM bifurcation lesions (2.22%). In multivariable model, 3 variables, including MV/SB diameter ratio, MV plaque ipsilateral to SB, and baseline diameter stenosis of SB, were independent predictors for SB occlusion (model C-statistic 0.829, 95% confidence interval [CI] 0.735-0.923, with good calibration). The risk score had a C-statistics of 0.830 (95% CI 0.738-0.923) with good calibration. Satisfactory discriminative ability of the risk score was also preserved in external validation (C-statistic 0.794, 95% CI 0.691-0.896).

CONCLUSIONS

The LM bifurcation-specific novel scoring system, LM V-RESOLVE, based on 3 simple baseline angiographic findings, could help to rapidly discriminate lesions at risk of SB occlusion during LM bifurcation PCI.

Management of failed stenting of the unprotected left main coronary artery

Percutaneous coronary intervention (PCI) is increasingly accepted as treatment for unprotected left main coronary artery (ULMCA) disease especially in those patients who are unsuitable for cardiac surgery. Treatment of any stent failure is associated with increased complexity and worse clinical outcomes when compared with de novo lesion revascularization. Intracoronary imaging has provided new insight into mechanisms of stent failure and treatment options have developed considerably over the last decade. There is paucity of evidence on the management strategy for stent failure in the specific setting of ULMCA. Treating any left main with PCI requires careful consideration and consequently treatment of failed stents in ULMCA is complex and provides unique challenges. Consequently, we provide an overview of ULMCA stent failure, proposing a tailored algorithm to guide best management and decision in daily clinical practice, with a special focus on intracoronary imaging characterization of causal mechanisms and specific technical and procedural considerations.