Five-year outcome after unprotected distal left main percutaneous coronary interventions according to complexity defined by DEFINITION criteria

Abstract Background Distal unprotected left main (LM) percutaneous coronary intervention (PCI) is known to be associated with inferior long-term outcomes compared with isolated ostial or shaft LM PCI. The complexity of the bifurcation lesion may impact selection of stenting strategy and outcome after PCI. Purpose Our aims were to investigate the five-year outcome after unprotected LM PCI according to complexity and determine the predictors of event-free survival. Methods We included consecutive patients who underwent unprotected LM PCI at our tertiary care centre between 1 January 2007 and 31 December 2014. LM trifurcation was the only exclusion criterion. Bifurcation lesion complexity was defined by the DEFINITION criteria. The LM lesion was defined as a complex if it met one major criterion for LM (side branch lesion length ≥10 mm and side branch diameter stenosis ≥70%) and two minor criteria (moderate to severe calcification, multiple lesions, bifurcation angle 45° or 70°, main vessel reference vessel diameter 2.5 mm, thrombus-containing lesions, main vessel lesion length ≥25 mm). The primary endpoint was the composite of cardiac death, target lesion myocardial infarction and target lesion revascularisation within 60 months. Results During the study period, 83 non-distal (ostial and/or shaft) and 355 distal (96 complex and 259 non-complex) LM lesion PCI were performed. 279 (78.6%) distal LM lesions were treated by provisional T-stenting strategy, among these 63 were complex and 216 were non-complex distal LM lesions. The 60-month event-free survival probability was lower in the complex distal group than in the non-complex distal (49.4% vs. 76.6%, p0.001), while there was no significant difference between the non-distal and non-complex distal groups (74.3% vs. 76.6%, p=0.590). Among the risk scores, the SYNTAX II was the most predictive (AUC=0.694) and the SYNTAX was the least predictive (AUC=0.530) in the complex distal LM lesion PCI group. Previous myocardial infarction (HR 2.386; 95% CI, 1.161-4.902, p=0.018) LVEF (HR 0.97; 95% CI, 0.944-0.998, p=0.033) and renal function (HR 0.969; 95% CI, 0.949-0.989, p=0.002) proved to be independent predictors of events within 60 months in the complex distal LM lesion PCI patients. Conclusion Our study showed that non-complex distal LM PCI with a single stenting strategy has a similarly good outcome as non-distal LM PCI. Complexity of the distal LM lesion, defined by the DEFINITION criteria, is a strong determinant of long-term cardiac events after PCI in unprotected LM patients. In complex distal LM lesion patients, in addition to anatomical parameters, clinical parameters are significant predictors of events after PCI.