Short-Term and Long-Term Clinical Impact of Stent Thrombosis and Graft Occlusion in the SYNTAX Trial at 5 Years

Objectives The aim of this study was to report the short-term and long-term clinical impact of stent thrombosis (ST) and graft occlusion (GO) in the final 5-year outcomes of the SYNTAX (SYNergy Between PCI With TAXUS and Cardiac Surgery) trial. Background The clinical effect of newer-generation drug-eluting stents and operative factors in complex coronary artery disease is uncertain. Methods The incidence of 5-year ST and GO, and their association with clinical outcomes, were analyzed in the randomized percutaneous coronary intervention and coronary artery bypass graft cohorts. ST and GO were defined by the SYNTAX protocol definitions (clinical presentation with acute coronary syndrome and angiographic/pathological evidence), the Academic Research Consortium (ARC) definition for ST, and the newly devised “ARC-like” definition of GO (i.e., definite, probable, or possible GO). Results At 5 years, 871 of 903 patients (96.5%) in the percutaneous coronary intervention cohort and 805 of 897 patients (89.7%) in the coronary artery bypass graft cohort completed follow-up. As compared with other vessel locations, protocol ST (72 lesions) occurred more frequently in the left main (14 of 72; 19%) and proximal coronary vasculature (37 of 72; 51%) and protocol GO (41 lesions) with grafts anastomosed to the distal right coronary artery (17 of 41; 42%). The incidence of 5-year ARC definite ST and ARC-like definite GO did not significantly differ (7% [n = 48] vs. 6% [n = 32], log rank p = 0.34); landmark analyses indicated significantly increased ARC definite ST within 30 days (3% [n = 19] vs. 1% [n = 6], log rank p = 0.033) but not >30 days to 5 years (4.2% [n = 29] vs. 4.5% [n = 26], log rank p = 0.78). At presentation, ARC definite ST (n = 48) and ARC-like definite GO (n = 32) were adjudicated to be linked to 4 (8%) and 0 deaths, respectively. At 5 years, ARC definite ST (n = 48) and ARC definite/probable ST (n = 75) were associated with 17 (17 of 48, 35.4%; median days to death: 0 days; interquartile range: 0 to 16 days; maximum: 321 days) and 31 (31 of 75, 41.3%; median: 0 days; interquartile range: 0 to 9 days; maximum: 721 days) cardiac deaths, respectively. At 5 years, ARC-like definite GO (n = 32) and ARC-like definite/probable GO (n = 53) were associated with 0 and 12 (12 of 52, 23.1%; median: 0 days; interquartile range: 0 to 14 days; maximum: 257 days) cardiac deaths, respectively. Conclusions Although the incidence of ST and GO was similar at 5 years, the clinical impact of ST appeared greater, with a negative impact on short-term to long-term mortality.