ABSTRACT: Background. Recent data suggest a clinical benefit with the systematic use of thrombus aspiration (TA) for the treatment of ST-elevation myocardial infarction (STEMI). Nevertheless, the impact of TA as a treatment strategy for stent thrombosis (ST) is unknown. This study aimed to analyze the impact of TA use for the treatment of ST on patient outcomes. Methods. From 2003 to 2008, 91 consecutive patients who presented with a definite ST were included in this analysis. We compared procedural success rates and the incidence of the composite criteria death-recurrent MI-recurrent ST at 30 days in patients who were treated with TA (TA group, n = 36) versus those who were not (No-TA group, n = 55). Results. Baseline characteristics were similar between the two groups except for the body mass index: 26.2 ± 5.4 vs. 29.3 ± 6.2 in the TA and No-TA groups, respectively (p = 0.028). ST presented more likely as STEMI in the TA group: 86.1% vs. 67.3% (p = 0.043). Except for TA use, there was no difference in the treatment therapeutics between groups, including for glycoprotein IIb/IIIa inhibitors. The rate of procedural success was higher in the TA group than in the No-TA group: 88.9% vs. 70.9% (p = 0.043). The incidence of the endpoint of death-recurrent MI-recurrent ST was significantly lower in the TA group: 22.2% vs. 47.2% (p = 0.026). By multivariate analysis, TA use was independently associated with a decrease in the composite criteria (HR = 0.45, p = 0.039). Conclusion. This study suggests that TA use for ST treatment permits an improvement in patient outcomes at 30 days with a significant decrease in the incidence of the composite criteria death-recurrent MI-recurrent ST. Further prospective studies are needed, however, to definitively address the benefit of TA use in this particular setting.
Key words: Thrombus aspiration, stent thrombosis, percutaneous
coronary intervention, myocardial infarction
J INVASIVE CARDIOL 2009;21:210–214
Stent thrombosis remains a major pitfall of stent implantation in contemporary percutaneous coronary intervention (PCI). According to the literature, the clinical presentation of stent thrombosis is acute myocardial infarction (MI) and its complications in 75% of the cases.1–3 The current treatment strategy is not well defined, but the principal objective of stent thrombosis treatment is to obtain effective reperfusion as quickly as possible.
Similarly for patients who present with ST-elevation MI (STEMI), the consensus is that patients who present with stent thrombosis should be brought emergently to the cardiac catheterization laboratory for primary PCI, rather than be treated with thrombolysis.4,5 Indeed, clinical trials in which the thrombus was aspirated along with human autopsy studies6 have demonstrated different thrombus composition in patients with stent thrombosis compared to patients with de novo STEMI. Indeed, the thrombus is almost totally composed of platelets and contains very low fibrin material in the case of stent thrombosis, which may impact the efficacy of thrombolysis for this indication. The pathophysiology of the thrombus formation and composition differs in patients with de novo STEMI who usually develop a thrombus due to ruptured plaque; while in patients with stent thrombosis, it is more likely the result of a lack of healing that leads to the occlusion of the stent.
Furthermore, a massive thrombus burden has been reported to be the rule rather than the exception in stent thrombosis. The prognosis of patients with de novo STEMI has been correlated to the degree of the thrombus burden and successful thrombus aspiration (TA). A recent study has suggested an important clinical benefit of systematic TA for the treatment of STEMI related to de novo lesions.7 Few small retrospective studies with Methods
Population and study design. In the present analysis, we included 91 consecutive patients who presented to our catheterization laboratory from June 2003 to March 2008 with definite stent thrombosis following drug-eluting stent (DES) implantation. Of the 91 patients admitted with definite stent thrombosis during this period, 36 were treated with TA (TA group) and 55 were not (No-TA group). The clinical and angiographic characteristics of these patients were systematically indexed.
PCI procedures for stent thrombosis treatment. PCI was performed according to the guidelines current at the time of the procedure.11 In all cases, the interventional strategy was at the discretion of the treating physician. All PCIs were performed by 6 different operators who were well matched between the two groups. Intraprocedural anticoagulation was ensured using bivalirudin or unfractionated heparin to achieve an activated clotting time of > 250 seconds in all patients. Glycoprotein (GP) IIb/IIIa inhibitors were used at the operator’s discretion and according to guidelines. All patients received an aspirin loading dose of 325 mg and continued this regimen indefinitely. After a clopidogrel loading dose of 600 mg, additional antiplatelet therapy with a 75 mg clopidogrel maintenance dose was instituted in all patients and was continued for > 1 year.
Follow up. Clinical follow up at 30 days was conducted by telephone contact or office visits with independent research personnel who were unaware of the objectives of the study. In cases of hospitalization, data were obtained by a systematic review of the discharge letter and all clinical events were adjudicated by source documentation by independent physicians who were not involved in the procedures. During the 30-day follow-up period, major adverse cardiac events (MACE), including death, recurrent MI and recurrent stent thrombosis, were systematically indexed.
Definitions. Procedural success was defined as thrombolysis in myocardial infarction (TIMI) flow grade 3 with a residual stenosis Results
Patient population. We studied the outcome of 91 consecutive patients who were admitted for definite stent thrombosis after DES implantation. Baseline clinical and angiographic patient characteristics are detailed in Table 1. Baseline clinical and angiographic characteristics were similar between the two groups except for the body mass index: 26.2 ± 5.4 versus 29.3 ± 6.2 in the TA and No-TA groups, respectively (p = 0.028).
Clinical presentation of stent thrombosis. Clinical presentation of stent thrombosis is detailed in Table 2. Overall, stent thrombosis presented as a STEMI in 74.7% of the cases and was complicated by a cardiogenic shock in 26.4% of the cases. Stent thrombosis presented more likely as STEMI in the TA group than in the No-TA group: 86.1% versus 67.3% (p = 0.043). The rate of cardiogenic shock was similar between the two groups: 22.2% versus 29.1% in the TA and No-TA groups (p = 0.467).
Treatment of stent thrombosis. Used in 32 patients (88.9%), the Export® catheter (Medtronic, Inc., Minneapolis, Minnesota) was the aspiration device used most. The Possis® system (Possis Medical, Inc., Minneapolis, Minnesota) was used in 3 cases (8.3%) and the Rinspirator® system (FoxHollow Technologies, Inc., Redwood City, California) in 1 case (2.8%). There was no complication of TA use in our population. The anticoagulation regimen, including the use of aspirin and clopidogrel, was similar in both groups. The treatment of stent thrombosis for each group is summarized in Table 3. Except for the use of TA, there was no difference in the treatment therapeutics between groups. The rate of GP IIb/IIIa inhibitor use was similar: 47.2% versus 48.1% in the TA and No-TA groups, respectively (p = 0.931). There was no statistical difference between the two groups in terms of new stent implantation rate: 69.4% versus 52.7% in the TA and No-TA groups, respectively (p = 0.131). The overall procedural success rate was 78%. The procedural success rate after stent thrombosis treatment was higher in the TA group versus the No-TA group: 88.9% versus 70.9%, respectively (p = 0.043) (Figure 1).
Patient outcomes. Patient outcomes are detailed in Table 4. The overall rates of death and the composite death-recurrent MI-recurrent stent thrombosis were 16.5% and 37.4%, respectively, at 30 days. The in-hospital rate of this composite was higher in the No-TA group as compared to the TA group: 40% versus 19.4%, respectively (p = 0.04). The clinical benefit was even higher at 30 days with this composite event rate of 22.2% in the TA group versus 47.2% in the No-TA group (p = 0.026) (Figure 2).
Predictors of outcomes. Independent predictors of the composite criteria (death-recurrent MI-recurrent stent thrombosis) at 30 days are displayed in Table 5. By multivariate analysis, predictors of the composite criteria occurrence were clinical presentation as an acute MI, cardiogenic shock, procedural success and TA use. TA use was independently associated with a decrease in the composite criteria death-recurrent MI-recurrent stent thrombosis (HR = 0.45, 95% CI = 0.2–0.9; p = 0.039).
Discussion
This study confirms that stent thrombosis remains a serious complication of PCI following DES implantation. In our series, definite stent thrombosis presented as STEMI in nearly 75% of the cases and was complicated by cardiogenic shock in 26.4% of the cases. Moreover, the rate of death was 16.5% at 30 days. Consequently, patients presenting with definite stent thrombosis had an extremely poor prognosis, including high rates of morbidity and mortality.1–3,14–16 More importantly, TA as a treatment strategy for stent thrombosis was independently associated with clinical benefit, including a higher rate of procedural success and a significant decrease in the rate of the composite criteria death-recurrent MI-recurrent stent thrombosis at 30 days.
The treatment of stent thrombosis is a critical point of care. In this context, it is currently well-recognized that the principal objective must be to obtain effective reperfusion as soon as possible. Wenaweser et al17 reported that the achievement of TIMI flow grade 3 and a residual diameter stenosis Conclusion
The present study reports a clinical benefit of systematic TA for patients presenting with stent thrombosis. TA was independently associated with a significant decrease in the composite endpoint death-recurrent MI-recurrent stent thrombosis at 30 days due to improved efficacy in achieving procedural success. Further prospective studies are needed, however, to definitively address the benefit of TA use as an adjunctive treatment for patients who present with stent thrombosis.
1. Cutlip DE, Baim DS, Ho KK, et al. Stent thrombosis in the modern era: A pooled analysis of multicenter coronary stent clinical trials. Circulation 2001;103:1967–1971.
2. Kuchulakanti PK, Chu WW, Torguson R, et al. Correlates and long-term outcomes of angiographically proven stent thrombosis with sirolimus- and paclitaxel-eluting stents. Circulation 2006;113:1108–1113.
3. Ong AT, Hoye A, Aoki J, et al. Thirty-day incidence and six-month clinical outcome of thrombotic stent occlusion after bare-metal, sirolimus, or paclitaxel stent implantation. J Am Coll Cardiol 2005;45:947–953.
4. Casserly IP, Hasdai D, Berger PB, et al. Usefulness of abciximab for treatment of early coronary artery stent thrombosis. Am J Cardiol 1998;82:981–985.
5. Hasdai D, Garratt KN, Holmes DR Jr, et al. Coronary angioplasty and intracoronary thrombolysis are of limited efficacy in resolving early intracoronary stent thrombosis. J Am Coll Cardiol 1996;28:361–367.
6. Jeong MH, Owen WG, Staab ME, et al. Porcine model of stent thrombosis: Platelets are the primary component of acute stent closure. Cathet Cardiovasc Diagn 1996;38:38–43.
7. Vlaar PJ, Svilaas T, van der Horst IC, et al. Cardiac death and reinfarction after 1 year in the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS): A 1-year follow-up study. Lancet 2008;371:1915–1920.
8. Rinfret S, Cutlip DE, Katsiyiannis PT, et al. Rheolytic thrombectomy and platelet glycoprotein IIb/IIIa blockade for stent thrombosis. Catheter Cardiovasc Interv 2002;57:24-30.
9. Silva JA, White CJ, Ramee SR, et al. Treatment of coronary stent thrombosis with rheolytic thrombectomy: Results from a multicenter experience. Catheter Cardiovasc Interv 2003;58:11–17.
10. Siddiqui DS, Choi CJ, Tsimikas S, Mahmud E. Successful utilization of a novel aspiration thrombectomy catheter (Pronto) for the treatment of patients with stent thrombosis. Catheter Cardiovasc Interv 2006;67:894–899.
11. Smith SC Jr, Feldman TE, Hirshfeld JW Jr, et al. ACC/AHA/SCAI 2005 Guideline Update for Percutaneous Coronary Intervention-Summary Article: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/SCAI Writing Committee to Update the 2001 Guidelines for Percutaneous Coronary Intervention). J Am Coll Cardiol 2006;47:216–235.
12. Thygesen K, Alpert JS, White HD. Universal definition of myocardial infarction. J Am Coll Cardiol 2007;50:2173–2195.
13. Cutlip DE, Windecker S, Mehran R, et al. Clinical end points in coronary stent trials: A case for standardized definitions. Circulation 2007;115:2344–2351.
14. de la Torre-Hernandez JM, Alfonso F, Hernandez F, et al. Drug-eluting stent thrombosis: Results from the multicenter Spanish registry ESTROFA (Estudio ESpanol sobre TROmbosis de stents FArmacoactivos). J Am Coll Cardiol 2008;51:986–990.
15. Iakovou I, Schmidt T, Bonizzoni E, et al. Incidence, predictors, and outcome of thrombosis after successful implantation of drug-eluting stents. JAMA 2005;293:2126–2130.
16. Pinto Slottow TL, Steinberg DH, Roy PK, et al. Observations and outcomes of definite and probable drug-eluting stent thrombosis seen at a single hospital in a four-year period. Am J Cardiol 2008;102:298–303.
17. Wenaweser P, Rey C, Eberli FR, et al. Stent thrombosis following bare-metal stent implantation: Success of emergency percutaneous coronary intervention and predictors of adverse outcome. Eur Heart J 2005;26:1180–1187.
18. Chechi T, Vecchio S, Vittori G, et al. ST-segment elevation myocardial infarction due to early and late stent thrombosis a new group of high-risk patients. J Am Coll Cardiol 2008;51:2396–2402.
19. Kaltoft A, Bottcher M, Nielsen SS, et al. Routine thrombectomy in percutaneous coronary intervention for acute ST-segment-elevation myocardial infarction: A randomized, controlled trial. Circulation 2006;114:40–47.
