MISSION - MISSION – Presented at AHA 2006

Description:

The goal of the trial was to evaluate percutaneous coronary intervention (PCI) using the cobalt chromium stent compared with the sirolimus-eluting stent (SES) among patients with ST elevation myocardial infarction (MI).

Study Design

Study Design:

Patients Screened: 575
Patients Enrolled: 316
Mean Follow Up: 1 year
Mean Patient Age: Mean age 59 years
Female: 22

Patient Populations:

Clinical and electrocardiographic evidence of ST elevation MI, de novo culprit lesion, reference vessel diameter 2.25-3.75 mm, and age 18-80 years

Exclusions:

Left main or triple-vessel disease, rescue PCI, or prior revascularization of the target vessel

Primary Endpoints:

In-lesion late loss at 9-month angiographic follow-up

Secondary Endpoints:

Death, MI, or revascularization at 30 days and 1 year; binary restenosis at 9 months, IVUS results

Drug/Procedures Used:

After crossing the lesion with the guidewire, patients were randomized to stenting using the Vision bare metal cobalt chromium stent (n = 158) or the SES (n = 158). Repeat angiography and intravascular ultrasound (IVUS) was performed at 9 months.

Concomitant Medications:

Clopidogrel (600 mg load), aspirin (300 mg load), and abciximab (0.25 mg/kg bolus)

Principal Findings:

Multivessel disease was present in 33% of patients and TIMI flow grade 0 or 1 was present in 70%. The culprit artery was the left anterior descending in 55% of patients. Direct stenting was used in 37% of cases. The mean number of stents implanted per patient was 1.36.

Angiographic follow-up was available in 82% of patients. The primary endpoint of in-segment late loss at 9-month angiographic follow-up was lower in the SES group compared with the bare metal group (0.12 mm vs. 0.68 mm, p < 0.001), as was percent diameter stenosis (24% vs. 41%, p < 0.001). Binary stenosis occurred less frequently in the SES group (3.8% vs. 22.8%, p < 0.01). In the subgroup of patients undergoing IVUS, percent neointimal volume was lower in the SES group than the bare metal group (3% vs. 27%, p < 0.001).

At 1 year, target vessel revascularization was performed in 13.3% of the bare metal group and 5.1% of the SES group (p = 0.01). There was no difference in death (2.7% vs. 1.3%) or MI (9.3% vs. 5.7%). Stent thrombosis occurred in 2.0% of the bare metal group and 1.3% of the SES group (p = NS).

Interpretation:

Among patients with ST elevation MI undergoing PCI, stenting with SES was associated with smaller late loss at 9-month angiographic follow-up compared with stenting with bare metal cobalt chromium stents.

The results of the present study are similar to those in the TYPHOON study, which also showed a reduction in late lumen loss and target lesion revascularization associated with SES use in ST elevation MI patients. However, both the present study and the TYPHOON trial differ from the results of the PASSION trial, which showed no difference between drug-eluting stents and bare-metal stents in target revascularization in primary PCI patients. A major difference between the trials is the performance of protocol-driven, repeat angiography, which was mandated in MISSION and TYPHOON, but not in the PASSION trial. As shown in many studies, protocol-driven angiography results in higher rates of revascularization compared with real world, symptom-driven revascularization rates. Additionally, the rate of late stent thrombosis (beyond 1 year) between SES and bare-metal stents is not known in the setting of primary PCI.

References:

Presented by Dr. Barend L. van der Hoeven at the American Heart Association Annual Scientific Sessions, Chicago, IL, November 2006.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Neointima, Myocardial Infarction, Follow-Up Studies, Cobalt, Drug-Eluting Stents, Sirolimus, Constriction, Pathologic, Electrocardiography, Percutaneous Coronary Intervention, Stents, Thrombosis, Chromium


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