Late Thrombotic Events After Bioresorbable Scaffold Implantation

Study Questions:

How does the long-term safety and efficacy of bioresorbable vascular scaffold (BVS) compare to everolimus-eluting stent (EES) in patients undergoing percutaneous coronary intervention?

Methods:

This is a systematic review and meta-analysis that included randomized trials that compared the clinical outcomes (safety and efficacy) of BVS to EES. Patients treated with either BVS or EES had to have at least a 24-month follow-up. A total of 5 randomized trials that evaluated a total of 1,730 patients was included.

Results:

The results demonstrated that the primary safety endpoint of definite/probable device thrombosis was significantly higher in the BVS-treated patients (2.4%, 95% confidence interval [CI]; 1.6-3.7) compared with 0.9% of patients in the EES group (95% CI; 0.3-2.1) (p = 0.01). There was also a higher rate of very late device thrombosis in those treated with BVS (1.4%, 95% CI; 0.08-0.25) compared with those receiving EES (0.5%, 95% CI; 0.2-1.6; odds ratio [OR] 3.04; 95% CI; 1.2-7.68, p = 0.03). Patients who received BVS were also at a higher risk of definite/probable device thrombosis compared with those receiving EES (OR 2.93, 95% CI; 1.37-6.26, p = 0.01). The primary efficacy endpoint was the risk of target lesion failure. This was defined as cardiac death, target vessel myocardial infarction, and ischaemia-driven target lesion revascularization. This occurred in 9.3% of patients in the BVS group (95% CI; 7.5-11.4) compared with 6.6 % in the EES group (95% CI; 4.8-8.8). There was also a trend toward a higher risk of target lesion failure in those treated with BVS compared with EES (OR 1.48 CI; 0.9-2.42, p = 0.09). This result was primarily driven by a higher risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularization. Of note, 92% of late vessel myocardial infarction that occurred in the BVS group occurred in the absence of dual antiplatelet therapy (DAPT). However, there was no difference in the risk of cardiac death between the two groups.

Conclusions:

Based on these results, it appears that patients treated with BVS have a significantly higher risk of definite/probable device thrombosis than those treated with EES. There is also a higher risk of ischaemia-driven target lesion failure associated with BVS compared with EES and also a trend toward a higher risk of target vessel myocardial infarction and target lesion failure in those treated with BVS. Additionally, the majority of very late scaffold thrombosis in the BVS group was in the absence of DAPT.

Perspective:

This is a meta-analysis and certainly warrants further investigation. The risk of device thrombosis that occurred in the absence of DAPT may indicate that early discontinuation may not be an option in patients with BVS. Shorter durations of treatment with DAPT in the new generation drug-eluting stents are being adopted.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Interventions and ACS

Keywords: Absorbable Implants, Acute Coronary Syndrome, Drug-Eluting Stents, Myocardial Infarction, Percutaneous Coronary Intervention, Stents, Thrombosis


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