Author + information
- Bruce R. Brodie, MD⁎ (, )
- Charles Hansen, MA,
- Ross F. Garberich, MS,
- Joseph A. Browning, MD,
- Patrick Tobbia, MD,
- Chauncy B. Handran, BS,
- M. Nicholas Burke, MD,
- Hemal Kadakia, MD,
- Thomas D. Stuckey, MD and
- Timothy D. Henry, MD
- ↵⁎Moses H. Cone Memorial Hospital, LeBauer Cardiovascular Research Foundation, 313 Meadowbrook Terrace, Greensboro, North Carolina 27408-6529
To the Editor:
Stent thrombosis (ST) is an infrequent but major complication after percutaneous coronary intervention (PCI) and frequently is associated with ST-segment elevation myocardial infarction (STEMI). As the population of stented patients has grown, the number of patients at risk for STEMI resulting from ST has increased, but data regarding the changing frequency and outcomes of STEMI resulting from ST treated with primary PCI are limited (1–3).
Our study population consisted of 3,305 consecutive patients with STEMI treated with emergency PCI at the Minneapolis Heart Institute (n = 2,086) or Cone Heart and Vascular Center (n = 1,219) from 2003 through 2010. Patients were treated with contemporary standards for primary PCI. Patients at the Minneapolis Heart Institute transported from long distances were given a half-dose of fibrinolytic therapy before transport.
Procedural data were entered by the interventional cardiologists. Hospitalization and post-hospitalization data were obtained by chart reviews and telephone contact by nurse coordinators. Definite ST was defined according to the Academic Research Consortium definition. All major events were adjudicated by one of the investigators (B.R.B., T.D.S., T.D.H.).
Categorical variables were compared using the chi-square or Fisher exact test, and continuous variables were compared with the Mann-Whitney U test. Kaplan-Meier estimates were compared with log-rank statistics. Multivariate analyses were performed with Cox regression.
Of 3,305 STEMI cases, 282 (8.5%) were the result of ST. The frequency increased from 6.0% from 2003 through 2004 to 10.9% from 2009 through 2010 (Fig. 1). The original stent implant was a drug-eluting stent in 60% of patients, and 95% of these were first-generation drug-eluting stents. The time from the original stent implant to STEMI resulting from ST was early (0 to 30 days) in 22%, late (31 to 365 days) in 22.0%, and very late (more than 365 days) in 56% of patients and was similar with a bare-metal stent or drug-eluting stent. The original stent was implanted for off-label indications in 73.6% of patients, including 43.3% for STEMI. Compliance with dual antiplatelet therapy at the time of ST was 33.5%, including 75.3% with early ST, 29.9% with late ST, and 11.7% with very late ST.
Patients with STEMI resulting from ST versus de novo occlusion had more diabetes, hypertension, prior myocardial infarction, and prior bypass surgery and had lower ejection fraction, lower frequency of Thrombolysis In Myocardial Infarction flow grade 2 to 3 on initial angiography, shorter door to balloon and reperfusion times, and more frequent use of glycoprotein platelet inhibitors and less frequent use of stents.
At 30 days, patients with STEMI resulting from ST had similar mortality rates (6.4% vs. 5.1%, p = 0.40) but more reinfarction (6.0% vs. 1.8%, p < 0.001) and ST (5.0% vs. 1.2%, p < 0.001). Clinical follow-up was obtained at more than 1 year in 85.8% of patients with a mean follow-up time of 2.1 years. At the 4-year follow-up, patients with STEMI resulting from ST had nonsignificantly higher rates of cardiac mortality (16.8% vs. 11.3%, p = 0.12) and higher rates of reinfarction (22.6% vs. 8.0%, p < 0.001) and ST (15.2% vs. 4.1%, p < 0.001) (Fig. 2).
After adjusting for differences in baseline variables, patients with STEMI resulting from ST compared with those with de novo occlusion had similar mortality (hazard ratio: 1.08, 95% confidence interval: 0.74 to 1.58, p = 0.68), but significantly higher rates of reinfarction (hazard ratio: 2.59, 95% confidence interval: 1.85 to 3.63, p < 0.001) and ST (hazard ratio: 3.43, 95% confidence interval: 2.28 to 5.18, p < 0.001).
Our study documents the increasing frequency of STEMI resulting from ST and documents worse outcomes compared with those associated with de novo coronary occlusion with higher frequencies of reinfarction and ST. Our study shares similarities with 3 smaller single-center studies, but with some key differences (1–3). Two of the 3 smaller studies found worse procedural outcomes and higher mortality in patients with STEMI resulting from ST, whereas our study did not. All 3 studies found higher rates of late reinfarction in patients with STEMI resulting from ST, similar to our study.
The increasing relative frequency of STEMI resulting from ST probably can be explained by the increasing number of patients who are at risk for very late ST, the fact that patients with stents seem to be at risk for ST for many years after implantation, and the fact that there has been some decrease in the frequency of STEMI resulting from de novo coronary occlusion. In our study, most patients with STEMI resulting from ST had very late ST (>1 year). It is also possible that the threshold for diagnosing ST could have changed over the study period because of changing thresholds for performing angiography in patients with acute coronary syndromes.
Efforts at prevention of STEMI resulting from ST include optimizing initial stent deployment, the use of new-generation stents, and the use of new and better antiplatelet therapy, including prasugrel and ticagrelor. These measures are most important when stents are implanted for off-label indications, especially for STEMI.
More aggressive management strategies in this high-risk group of patients may be required to improve outcomes. Because procedural results have been shown to be poorer in some studies, new procedural strategies may be needed, including increased use of glycoprotein platelet inhibitors, the more frequent use of thrombectomy devices and intravascular ultrasound to guide therapy, and the use of new-generation stents when new stents are required. The use of new antiplatelet agents, such as prasugrel and ticagrelor, which have been shown to reduce the frequency of ST in STEMI patients, should be used in eligible patients, and more frequent prophylactic revascularization with bypass surgery may be warranted.
In conclusion, ST accounts for an increasing proportion of STEMI patients and is associated with an increased frequency of reinfarction and subsequent ST compared with de novo coronary artery occlusion. New strategies are needed to address this growing problem.
Please note: This study was supported by an unrestricted grant from the LeBauer Charitable Research Foundation and the Minneapolis Heart Institute Foundation. Dr. Brodie is on the Speaker's Bureau for Medicines Company and Medrad/Possis. Dr. Stuckey is a consultant for, is on the Speaker's Bureau of, and is on the Advisory Board for Boston Scientific Corporation. Dr. Burke is a consultant to BridgePoint Medical and Terumo Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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- Vecchio S.,
- Vittori G.,
- et al.