Predictive value of residual SYNTAX score for clinical outcomes after High-Risk Percutaneous Coronary Intervention (HR-PCI): Evidence from pooled analysis of prospective studies

Abstract

Abstract Background/Introduction Completeness of revascularisation (CR) after percutaneous coronary intervention (PCI), which is associated with improved long-term patient outcomes, is commonly quantified with the post-PCI residual SYNTAX score (rSS). In High-Risk PCI (HR-PCI), trans-axial percutaneous Left Ventricular Assist Devices (pLVADs) provide higher procedural mechanical circulatory support than intra-aortic balloon pump (IABPs). We hypothesise that pLVADs may contribute to higher CR during HR-PCI. A direct quantitative relationship between revascularisation extent, measured via rSS, and long-term clinical outcomes has not yet been established in HR-PCI. NYHA Class allocation 90-days post-PCI and Ejection Fraction (EF) have been shown strongly predictive of long-term survival, Heart Failure (HF) hospitalization risk and Quality of Life (QoL). Purpose To investigate the relationship between revascularization completeness, NYHA Class and LVEF 90-days in patients undergoing HR-PCI with either pLVAD or IABP support. Methods Individual patient data (IPD) from the PROTECT II and RESTORE-EF prospective studies of pLVADs during HR-PCI were pooled. Using patients with sufficient information, ordinal logistic regressions were performed for NYHA and EF at 90-days post-PCI. All models were refined using stepwise deletion (threshold=0.05) and included treatment group (pLVAD or IABP), baseline age, gender, race, NYHA Class at baseline, LVEF at baseline, SYNTAX Score at baseline and post-procedural rSS. Results NYHA Class utilised 641 patients (484 pLVAD;157 IABP). Baseline SYNTAX, rSS and LVEF at baseline were significant predictors of NYHA Class at 90-days post HR-PCI. Specifically, a single-unit decrease in rSS increases the odds of the patient improving NYHA at 90-days vs. baseline by 2.2%±1.0% (Mean±SE, p=0.021). Utilising solely the subjects with sufficient information enrolled in PROTECT II (178 pLVAD; 157 IABP), post-procedural rSS was the only significant predictor of NYHA Class at 90-days with every single-unit decrease in rSS increasing the odds of NYHA improvement by 3.0%±1.2% (p=0.017). EF examined 622 (405 pLVAD; 217 IABP). Baseline SYNTAX, rSS and baseline LVEF significantly predicted Ejection Fraction at 90-days. A single-unit decrease in rSS leads to an absolute higher LVEF at 90-days of 0.246%±0.05% (p<0.001). Treatment group statistically predicted LVEF at 90-days. For the same level of revascularisation, pLVAD-supported procedures result in an absolute higher LVEF of 4.13%±1.21% (p=0.001). Conclusions Completeness of revascularization, as measured by level of reduction in rSS after a HR-PCI, is significantly predictive of NYHA Class improvement and Ejection Fraction gains at 90-day follow-up. pLVADs were also shown to further increase LVEF at 90-days vs. IABP. These data further support the need for complete revascularization in this patient population and help make additional therapeutic decisions post-PCI.