Federal health regulators are reviewing reports of problems with a heart implant designed to dissolve into the body, following a high rate of cardiovascular events, such as heart attacks, cardiac arrest and death.
In a letter to health care providers sent on March 18, the FDA indicates that an investigation has been launched into safety issues with Abbott Vascular’s Absorb G1 Bioresorbably Vascular Scaffold (BVS). According to the FDA, approximately 11% of BVS recipients have suffered major adverse cardiac events.
The BVS is a surgical implant used to open coronary arteries blocked by plaque to increase blood flow to the heart. The device, implanted during an angioplasty procedure, eventually dissolves and is absorbed by the body.
Abbott’s BVS was approved by the FDA in July 2016. However, according to the letter, two-year data from a clinical trial, known as ABSORB III, used to convince the FDA to approve the device, indicates a much higher rate of heart problems than expected. Initially, the FDA approved the device looking at only one year of clinical trial data.
“The FDA’s initial review of two-year data from the BVS pivotal clinical study (the ABSORB III trial) shows an 11 percent rate of major adverse cardiac events (e.g., cardiac death, heart attack, or the need for an additional procedure to re-open the treated heart vessel) in patients treated with the BVS at two years, compared with 7.9 percent in patients treated with the already-approved Abbott Vascular’s metallic XIENCE drug-eluting stent,” the FDA letter states. “This study also shows a 1.9 percent rate of developing blood clots (thrombosis) within the BVS versus 0.8 percent within the XIENCE stent at 2 years. These observed higher adverse cardiac event rates in BVS patients were more likely when the device was placed in small heart vessels.”
The FDA notes that patients who receive coronary stents are required to take dual antiplatelet therapy, typically a combination of aspirin and Plavix, or a similar blood thinner. The agency indicates that most patients who developed blood clots within a year or being implanted with the BVS had discontinued the drug therapy.
While the FDA continues its investigation, it is advising health care providers to closely follow instructions on selecting heart vessels for BVS implants; to warn patients to be aware of any symptoms of heart problems and immediately seek medical attention; to advise patients to stick to their dual antiplatelet therapy; and to report any BVS-related adverse events to the FDA’s MedWatch adverse event reporting program.