麻豆传媒

Safety issues plaguing the Absorb bioresorbable vascular scaffold (BVS) seem to get worse over time, a meta-analysis confirmed -- on the heels of the device's retreat from the global market.

A pooling of seven randomized trials and 38 observational studies showed that the device was associated with a 1.8% rate of scaffold thrombosis by the end of the first year, which shrank slightly to 0.8% after that, according to Biao Xu, MD, PhD, of China's Nanjing University School of Medicine, and colleagues, writing in Annals of Internal Medicine.

Randomized trials comparing BVS with drug-eluting metallic stents showed with the former (2.41% versus 0.69%, OR 3.40, 95% CI 2.01-5.76) over the longest follow-up, a median of 25 months. The gap was apparent within the first year (1.55% versus 0.56%, OR 2.59, 95% CI 1.44-4.66), and widening thereafter (8.62% versus 0.13%, OR 4.81, 95% CI 1.82-12.67).

Over this time, Absorb-implanted patients also experienced more myocardial infarctions (6.57% versus 4.02%, OR 1.63, 95% CI 1.26-2.10), target lesion revascularization (6.17% versus 4.85%, OR 1.31, 95% CI 1.03-1.67), and target lesion failure (9.96% versus 7.49%, OR 1.37, 95% CI 1.12-1.66) -- with odds again climbing higher over time.

The investigators acknowledged that the findings are not generalizable to other BVS's; another caveat to the study is the relatively limited follow-up period.

Nonetheless, these findings "demonstrate that many of the purported benefits of BVS resorption have not been realized, and it seems increasingly unlikely that any BVS platform will put a dent in the dominance of metallic stents," Sanket Dhruva, MD, and Jeptha Curtis, MD, both of Yale University School of Medicine in New Haven, Connecticut wrote in an .

"If the findings seem familiar to Annals readers, it is no mistake. The article represents an update of a 2016 study published in Annals by many of the same investigators. That study focused on outcomes at a median follow-up of 10.5 months after BVS implantation."

Dhruva and Curtis called the current study update a "credit" to the investigators and the Annals editorial staff: "It would have been easy to discount the study as merely representing a marginal incremental advance and relegate it to a lower-tier journal. Instead, decision-makers recognized that despite superficial similarities, the updated study addresses key knowledge gaps regarding clinically meaningful differences in longer-term outcomes associated with BVS and provides the quantitative estimates physicians and patients need to have informed discussions about scaffold selection."

Noting, though, that Abbott already decided to halt sales of the first-generation Absorb BVS in September, the editorialists suggested that the meta-analysis came just a little too late: "Although publishers are actively working to reduce review times, months and sometimes years pass between manuscript submission and publication. As important as [these] findings ... are to defining the role of the Absorb BVS in clinical practice, the authors missed an opportunity to truly affect the BVS debate."

This may be a larger issue for the peer-reviewed literature in general, the editorial continued: "Peer-reviewed publication remains a priority for researchers, particularly those associated with academic institutions, but we need mechanisms to get the preliminary findings into circulation before publication." Dhruva and Curtis suggested that the field of medical research follow other disciplines in adopting the practice of preprinting.

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