Long-term Outcomes in Patients Undergoing Percutaneous Coronary Intervention with Drug-eluting Stents

Roberta Rossini; Giuseppe Musumeci; Alessandro Aprile; Orazio Valsecchi

Disclosures

Expert Rev Pharmacoeconomics Outcomes Res. 2010;10(1):49-61. 

In This Article

Controversial Issue: Use of DES in ACS

Acute coronary syndrome at presentation is associated with a higher risk of stent thrombosis.[28–30] Patients enrolled in randomized trials were carefully selected and represented only a small fraction of those encountered in everyday clinical practice. Moreover, prior randomized studies excluded patients with ST-elevation MI. Consequently, primary PCI represented, for a long time, a setting in which the use of DES was controversial owing to the large thrombus burden and possible higher risk of subsequent stent thrombosis.

The pathophysiological mechanism underlying the increased risk of stent thrombosis in patients with ACS, is the trapping of thrombus between the stent struts and vessel wall, which might contribute to late acquired malapposition after thrombus resolution.[31] Furthermore, stenting of necrotic core-rich plaques might result in stent strut penetration into the necrotic core with ensuing tissue prolapse and plaque disruption that might also contribute to stent thrombosis.[32]

The Trial to Assess the use of the CYPHER® Stent in Acute Myocardial Infarction Treated with Balloon Angioplasty (TYPHOON) study was the first randomized, prospective, multicenter study that assessed the clinical outcome of SES in ST-elevation MI.[33] In this randomized study conducted in more than 700 ST-elevation MI patients the, DES use was associated with a better outcome and there was no evidence of a difference in cumulative stent thrombosis (3.6% in SES vs 3.4% in BMS). Some perplexities were raised by the high rate of thrombosis in both groups and the key exclusion criteria.

A recent study by Kukreja et al. evaluated the risk of stent thrombosis of DES versus BMS in patients treated for ACS.[32] The results confirmed the previous findings that presentation with ACS is a risk factor for stent thrombosis. This excessive risk occurred with both BMS and DES across all time points, with the exception of very late stent thrombosis, which appeared to be a unique feature of DES implantation. The only independent predictor of very late stent thrombosis was DES implantation. Clopidogrel was prescribed for longer in DES than in BMS patients (6 ± 3 vs 2 ± 2 months, p < 0.001 in unstable angina/MI without ST-segment elevation; 6 ± 3 vs 2 ± 1 months in ST-elevation MI, p < 0.001).

Mauri et al. published a registry of 7217 patients who were treated for acute MI (4016 with DES and 3201 with BMS[34]). According to analysis of matched pairs, the 2-year, risk-adjusted mortality rates were lower for DES than for BMS among all patients with MI (10.7 vs 12.8%; p = 0.02), among patients with MI with ST-segment elevation (8.5 vs 11.6%; p = 0.008) and among patients with MI without ST-segment elevation (12.8 vs 15.6%; p = 0.04). The 2-year, risk-adjusted rates of recurrent MI were reduced in patients with MI without ST-segment elevation who were treated with DES, and repeat revascularization rates were significantly reduced with the use of DES compared with BMS in all groups.

The Harmonizing Outcomes with Revascularization and Stents (HORIZONS) trial was a large-scale, international, prospective, randomized study comparing PES with BMS in patients with evolving ST-segment elevation MI.[35] The study was powered for safety as well as efficacy, with follow-up angiographic assessment performed only after the primary clinical end point had been evaluated. A total of 2257 patients were randomized to PES, whereas 749 patients received identical BMS. The two primary end points of the study were the 12-month rates of TLR for ischemia (analysis powered for superiority) and a composite safety outcome measure of death, reinfarction, stroke or stent thrombosis (powered for noninferiority with a 3.0% margin). The major secondary end point was angiographic evidence of restenosis at 13 months. Patients who received PES, compared with those who received BMS, had significantly lower 12-month rates of ischemia-driven TLR (4.5 vs 7.5%; p = 0.002) and TVR (5.8 vs 8.7%; p = 0.006), with noninferior rates of the composite safety end point (8.1 vs 8.0%; p = 0.01 for noninferiority; p = 0.92 for superiority). Patients treated with PES and those treated with BMS had similar 12-month rates of death (3.5 and 3.5%, respectively; p = 0.98) and stent thrombosis (3.2 and 3.4%, respectively; p = 0.77). The 13-month rate of binary restenosis was significantly lower with PES than with BMS (10.0 vs 22.9%; p < 0.001).

At 2 years, there was a significant reduction in ischemic TLR and TVR (6.8 vs 11.6%; p < 0.001), with no evidence of late catch-up. More important, there were comparable rates of all-cause mortality (4.3 vs 5.2%; p = 0.32), reinfarction and stent thrombosis (4.1 vs 4.1%%; p = 0.99), with the two stents.

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