Within the PCI and CABG arms of the All-Comers SYNTAX trial, incomplete revascularization that is angiographically determined has a detrimental impact on long-term clinical outcomes, including mortality. This effect remained consistent in patients with and without total occlusions, according to the study authors.

The post hoc study of the All Comers SYNTAX (SYNergy between PCI with TAXus and Cardiac Surgery) trial was published Jan. 22 in the Journal of the American College of Cardiology.

In patients with complex coronary artery disease—namely, unprotected left main coronary artery or de novo three-vessel disease—who undergo CABG surgery or PCI, the long-term prognostic implications of complete vs. incomplete revascularization is “unsettled,” wrote the study authors. Also, recent studies have suggested that angiographic complete revascularization after CABG revascularization might not be associated with a significant improvement in long-term clinical outcomes (Circulation 2011;123:2373-2381/Eur J Cardiothorac Surg 2012;41:535-541).

The purpose of this study, according to the authors, was to report the four-year clinical impact of complete and incomplete angiographic revascularization in the All-Comers SYNTAX trial.

First, the All-Comers SYNTAX trial provided an opportunity for the assessment of patients where selection bias in enrolling patients was minimal and therefore was potentially more representative of contemporary clinical practice, wrote Vasim Farooq, MBCHB, of the interventional cardiology department at Erasmus University Medical Centre, Thoraxcenter in Rotterdam, the Netherlands, and colleagues. Secondly, they examined the presence of total occlusions to influence the ability of PCI or CABG to achieve complete revascularization, on the  hypothesis that failure to treat total occlusions would have a significantly detrimental impact on long-term clinical outcomes in PCI- and CABG-treated patients.

In this post hoc study consisting of randomized (1,800 patients) and nested PCI (198 patients) and CABG (649 patients) registries, the researchers compared the four-year clinical outcomes in groups, with and without angiographic complete revascularization, in the PCI and CABG arms. They analyzed the clinical outcomes with Kaplan-Meier estimates, log-rank comparisons and Cox regression analyses. They also determined multivariate predictors of incomplete revascularization. Similar analyses were undertaken in the total occlusion and non-total occlusion treated groups of both study arms.

Farooq et al reported that angiographic complete revascularization was achieved in 52.8 percent of the PCI arm and 66.9 percent of the CABG arm. Within the PCI and CABG arms, incomplete revascularization (compared with complete revascularization) “seemed to be a surrogate marker of a greater burden of anatomical coronary complexity and clinical comorbidity,” wrote the authors, “and was associated with significantly higher frequencies of four-year mortality, all-cause revascularization, stent thrombosis (PCI arm) and major adverse cardiac and cerebrovascular events.”