Stent thrombosis predicts poor STEMI outcome

23 June 2008

MedWire News: Research shows that patients with ST-segment elevation myocardial infarction (STEMI) caused by stent thrombosis (ST) have a poorer short-term prognosis than patients with de novo coronary thrombosis.

"ST identifies a subgroup of patients with STEMI with poor angiographic and early clinical outcomes, suggesting that the management of these patients should be improved," Sabine Vecchio (Cardiologia e Cardiologia Invasiva 2, Florence, Italy) and colleagues say.

Up to 70% of patients with ST develop STEMI but there are little data comparing the prognosis of these patients with that of STEMI patients without a history of thrombosis.

To investigate, the team followed-up for 6 months 115 ST patients, 80% of whom were diagnosed with STEMI, and 98 patients with a de novo STEMI, all of whom underwent primary percutaneous coronary intervention.

Analysis showed that ST patients were less likely to achieve the primary endpoint of reperfusion than their de novo STEMI counterparts (80.4% vs 96.9%) and had a higher risk for distal embolization (6.5% vs 0.0%).

In propensity-adjusted binary logistic regression, ST was the only independent predictor for unsuccessful reperfusion (odds ratio=6.8).

The patients were also followed-up for inhospital and 6-month rates of major adverse cardiovascular and cerebrovascular events (MACCE), defined as death, nonfatal myocardial reinfarction, target vessel revascularization (TVR), and cerebrovascular accident.

Patients with ST had a higher inhospital MACCE rate than patients with de novo STEMI (25.6% vs 9.2%), and this was attributed to an increased risk for mortality, reinfarction, and TVR. However, ST was not a significant independent predictor for inhospital mortality in further analyses.

At the 6-month checkpoint, MACCE rates did not significantly differ between ST and de novo STEMI patients (11.3% vs 9.9%), with myocardial reinfarction the only factor occurring more frequently in ST patients than de novo STEMI patients (4.2% vs 0%).

Writing in the Journal of the American College of Cardiology, the researchers say their findings could be used to improve outcomes in patients with ST-related STEMI.

They suggest the large thrombus burden and high risk for distal embolization could make ST STEMI patients good candidates for thrombotic protection/extraction devices in conjunction with glycoprotein IIb/IIIa inhibitors.

Suggesting that procedural and clinical outcomes of ST could be improved by identifying and correcting any procedural issues leading to ST and thus avoiding recurrence, the team concludes: "Intravascular ultrasound analysis, performed either during or - even better - after the acute phase of ST, should be considered to assess the optimal stent deployment and the presence of residual dissection."

J Am Coll Cardio 2008; 51: 2396-2402