Implantation of a first-in-man fully biodegradable coronary stent made of poly-L-lactic acid was associated with a low rate of major adverse cardiac events and scaffold thrombosis in patients with stable ischemic heart disease after 10 years of follow-up.
Researchers in Japan conducted a single-arm, observational, prospective study of 50 patients (44 men; mean age, 61 years) with stable ischemic heart disease who were treated with 84 fully biodegradable coronary stents between September 1998 and April 2000. The stent studied was the Igaki-Tamai (Kyoto Medical Planning Co.), which is currently used in nine countries in the European Union and Turkey but not in the United States, to treat peripheral arterial disease. The stent is not yet approved by any country for the treatment of CAD.
After an average of 10 years of follow-up, one cardiac death, six noncardiac deaths and four MIs occurred. Results showed that the survival rate was 98% free from cardiac death and 87% free from all-cause death with the fully biodegradable coronary stent. In addition, 50% of patients experienced no major adverse cardiac events, including all-cause death, nonfatal MI, target lesion revascularization and target vessel revascularization. Acceptable major event complication rates were similar to those for bare metal stents, according to the researchers.
Cumulative rates of target lesion revascularization were 16% at 1 year, 18% at 5 years and 28% at 10 years. Cumulative rates of target vessel revascularization were 16% at 1 year, 22% at 5 years and 38% at 10 years.
The researchers observed two definite scaffold thromboses, one subacute and one very late. According to the researchers, the case of very late definite scaffold thrombosis was related to a sirolimus-eluting stent that was implanted for a lesion that was proximal to the fully biodegradable stent. No other patients experienced in-hospital major adverse cardiac events during follow-up.
IVUS data showed that stent struts “mostly disappeared” within 3 years, according to the study results.
“We have needed this long-term clinical data to clarify the coronary safety of the stent,” Kunihiko Kosuga, MD, PhD, director of cardiology at Shiga Medical Center for Adults in Moriyama City, Japan, said in a press release. “Our findings will pave the way for the entry of coronary stents made of biodegradable polymers into the real world of interventional cardiology.”
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Disclosure: Dr. Kosuga reports no relevant financial disclosures. Keiji Igaki, PhD, is the inventor and developer of the Igaki-Tamai stent.