Stent Thrombosis Post Non-cardiac Surgery
Stent Thrombosis Post Non-cardiac Surgery
Abstract & Commentary
By Michael H. Crawford, MD. This article originally appeared in the September 2010 issue of Clinical Cardiology Alert. It was peer reviewed by Ethan Weiss, MD.
Source: Chia KKM, et al. Frequency of late drug-eluting stent thrombosis with non-cardiac surgery. Am J Cardiol. 2010;106:1-3.
There is considerable concern regarding in-stent thrombosis of drug-eluting stents (DES) when aspirin and clopidogrel are stopped for non-cardiac surgery (NCS), but a paucity of data. Thus, this group from Australia surveyed more than five million patients in two large private insurance company databases and sent questionnaires to all who had DES followed by surgery. Questionnaires were returned by 1,086 of the 4,126 patients who received them. Cardiac surgery excluded 376, leaving 710 who were suitable for analysis. None of the non-responders died within 30 days of NCS. Mean time from DES to NCS was 348 days. NCS occurred within 30 days in 3%, six months in 27%, and 12 months in 56%. Before surgery, 66% were on dual antiplatelet therapy, 21% aspirin alone, 9% on clopidogrel alone, and 4% were on no antiplatelet therapy. Surgery was performed on dual therapy in 18%, on single therapy in 23%, and no antiplatelet therapy in 59%. The average time of medication cessation prior to surgery was about one week.
Results: Perioperative myocardial infarction (MI) (confirmed by medical records) occurred in 11 (1.5%), and angiography showed that only two patients had stent thromboses while seven had new culprit lesions. Two patients did not have angiography, but one probably had in-stent thrombosis clinically, for a total of three. None of these three patients were on antiplatelet therapy, and only one of the other eight patients was on therapy with aspirin alone. Among the 11 MIs, one occurred < 30 days post-DES, none from one to six months, six from six to 12 months, and four >12 months. The authors concluded that NCS after DES has a low morbidity despite a majority being off antiplatelet therapy and more post-operative MIs occurred because of new culprit lesions in non-stented vessels, rather than stent thrombosis.
Commentary
A remarkable fact of this study is the high rate of NCS after DES (44%). This may be because their database started shortly after DES was introduced in Australia in 2002, before stent thrombosis with DES was appreciated. If NCS is likely, a bare-metal stent is placed, or only balloon angioplasty is performed. Also, 41% of patients had NCS on one or more antiplatelet agents despite the known higher risk of bleeding. Perhaps the most interesting results of this study are the low rate of post-NCS MI (1.5%) and only 3 of 11 patients had stent thrombosis (0.4%). Thus, the risk of DES thrombosis is quite low with NCS. Since some patients in this study were still on antiplatelet therapy, the rate may have been approximately twice as high if all had been off therapy, but still probably < 1%. Only about one-quarter of the patients surveyed returned the questionnaire, but since those with problems may have been more likely to return it, this result may be an overestimation of post-NCS MI.
One strength of this study is that angiographic confirmation was obtained in all but one of the MI patients. This patient had terminal cancer and a small troponin leak, so it was decided to treat the patient conservatively. The angiographic results point to the value of doing angiography, since a high proportion of the MI patients had new culprit lesions. The key question is whether we should change our practice based upon this study and allow antiplatelet therapy to be withheld for NCS in post-DES patients within 12 months? If stent thrombosis with NCS on no therapy is really < 1%, it is going to be hard to argue that antiplatelet therapy is necessary in all cases. In a well-deployed proximal vessel stent, it may be safe to be off therapy for a short time but, a left-main stent, hanging into the aorta, may be too risky. Perhaps a case-by-case approach is reasonable.
There is considerable concern regarding in-stent thrombosis of drug-eluting stents (DES) when aspirin and clopidogrel are stopped for non-cardiac surgery (NCS), but a paucity of data.Subscribe Now for Access
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