Short and Long Term Clinical Impact of Stent Thrombosis and Graft Occlusion in the Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery Trial: The SYNTAX Trial at 5 Years

Study Questions:

What is the short- and long-term clinical impact of stent thrombosis (ST) and graft occlusion (GO) in patients with complex coronary artery disease?


The authors used 5-year outcome data from the SYNTAX trial to assess the incidence of 5-year ST and GO, and their association with clinical outcomes, in the randomized percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) cohorts. ST and GO were defined as per the SYNTAX protocol definitions (clinical presentation with acute coronary syndrome and angiographic/pathological evidence). They also reported ST based on the Academic Research Consortium (ARC) definition, and GO using the newly devised “ARC-like” definition for GO (i.e., definite, probable, or possible GO).


Incidences of 5-year ARC definite ST and ARC-like definite GO were similar (7% vs. 6%, p = 0.34). ST (72 lesions) occurred more frequently in the left main (14/72, 19%) and proximal coronary vasculature (37/72, 51%), whereas protocol GO (41 lesions) was more common with grafts anastomosed to the distal right coronary artery (17/41, 42%). 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 (35%) and 31(41%) 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 (22.6%) cardiac deaths, respectively.


The authors concluded that although ST and GO had similar incidences at 5 years, ST was much more strongly associated with short- to longer-term mortality.


This important study demonstrates the relative negative impact of ST compared with graft occlusion. Part of the reason has to do with the dramatic longevity of the left internal mammary artery (LIMA) graft to the left anterior descending artery (LAD). The patency of this graft ensures that a large part of the heart is protected and better able to handle infarction or ischemia at other sites. The incidence of ST has declined with the use of second-generation drug-eluting stents, but it still carries significant mortality and morbidity. Further enhancements in stent design and pharmacotherapy, along with optimization of PCI technique, is needed to minimize the occurrence of this rare complication.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Interventions and ACS, Interventions and Coronary Artery Disease

Keywords: Acute Coronary Syndrome, Myocardial Infarction, Coronary Artery Disease, Morbidity, Drug-Eluting Stents, Electrocardiography, Angioplasty, Balloon, Coronary, Percutaneous Coronary Intervention, Thrombosis, Mammary Arteries, Coronary Vessels, Cardiac Surgical Procedures, Coronary Artery Bypass

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