Stent Thrombosis During PCI Rare but Serious Phenomenon

Intraprocedural stent thrombosis is a relatively rare complication of percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS), occurring less than 1% of of the time, but it is strongly associated with subsequent stent thrombosis and death, according to a study published online December 19, 2012, ahead of print in JACC: Cardiovascular Interventions. The researchers suggest creating a separate, routinely reported category of stent thrombosis for episodes that occur during PCI.

Sorin J. Brener, MD, of Weill Cornell Medical College (New York, NY), and colleagues from Columbia University Medical Center and Mount Sinai Medical Center reviewed angiograms from the ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) and HORIZONS-AMI (Harmonizing Outcomes with RevascularIZatiON and Stents in Acute Myocardial Infarction) trials to determine the incidence and consequences of intraprocedural stent thrombosis in 6,591 patients with ACS undergoing PCI. The phenomenon was defined as new or increasing thrombus within or adjacent to a deployed stent occurring during the index PCI procedure, whether occlusive or nonocclusive.

Intraprocedural stent thrombosis was observed in 47 patients (0.7%). Major adverse ischemic events were markedly higher in those individuals, including mortality, MI, TVR, and subsequent Academic Research Consortium-defined stent thrombosis at both 30 days and 1 year (table 1).

Table 1. Clinical Outcomes

Abbreviations: ST, stent thrombosis
^a Defined by Academic Research Consortium criteria.

Multivariate analysis showed that intraprocedural stent thrombosis was an independent predictor of 1-year mortality (HR 3.86; 95% CI 1.66-9.00; P = 0.002). Other predictors were diabetes, final TIMI flow grade 0-2, and baseline creatinine clearance.

Complication Linked to Clinical Presentation, Procedural Factors

“We conclude that the occurrence of [intraprocedural stent thrombosis] is relatively rare, even in ACS patients, and is related more strongly to clinical presentation and procedural factors (e.g., anticoagulation regimen, lesion type, and presence of thrombus at baseline) than to baseline demographic characteristics,” Dr. Brener and colleagues write.

Since intraprocedural stent thrombosis is strongly associated with a substantial excess of out-of-lab stent thrombosis in the first 30 days after PCI, they observe, affected patients “might especially benefit from more potent antiplatelet agents, such as prasugrel or ticagrelor.”

Also, because the complication is a powerful independent predictor of 1-year mortality, it should be “added as a separate category to the ARC definition of [stent thrombosis] and be recognized as a high-risk procedural complication portending a poor prognosis.”

Important Predictive Ability

In a telephone interview with TCTMD, Dr. Brener said it is important to pay attention not only to what happens after PCI, but what happens during the procedure as well. “There are patients, particularly in the setting of acute coronary syndromes, that have a lot of intraprocedural complications that are not monitored,” he said. “So you don’t really know what’s happening during the procedure and . . . we are really missing a good portion of the story.”

As for prevention, Dr. Brener said better anticoagulation alone or in combination with aspiration thrombectomy could possibly resolve intraprocedural stent thrombosis, but repairing the lesion or vessel in a different way might also be the correct approach. “Until you know how big the problem is and what the consequences are, you don’t know if you need a different strategy,” he said.

The fact that intraprocedural stent thrombosis raises the mortality risk even if the procedure is successful was “unexpected,” according to Dr. Brener. But this circumstance “will improve our ability to predict” the complication, especially in patients with ACS, he said.

Dr. Brener said he looks forward to the results of the PHOENIX trial, which analyzed more than 12,000 stable patients who underwent PCI. “We’ll have all this information, and we’ll see how it correlates with outcomes,” he said. “It’s possible that when we put it all together we’ll say that intraprocedural stent thrombosis, and in general intraprocedural thromboembolic complications, are important for all patients; or we’ll say no, they are particularly important for patients with acute coronary syndromes and maybe with STEMI, [but] less important for patients with non-STEMI and potentially of almost no significance for stable patients.”

Study Details

Patients who experienced intraprocedural stent thrombosis were more likely to have STEMI, higher white blood cell count on admission, randomization to bivalirudin alone, subsequent bail-out with a glycoprotein IIb/IIIa inhibitor, 1-vessel coronary artery disease, an occluded artery at baseline with thrombus, bifurcation lesions, and implantation of BMS vs. DES.

Note: Dr. Brener and several coauthors are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 

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Source:
Brener SJ, Cristea E, Kirtane AJ, et al. Intra-procedural stent thrombosis: A new risk factor for adverse outcomes in patients undergoing percutaneous coronary intervention for acute coronary syndromes. J Am Coll Cardiol Intv. 2012;Epub ahead of print.

 

 

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