OPTIMAX: First-in-Human Results Promising for Biocompatible Cobalt-Chromium Stent

Use of a novel titanium-nitride-oxide-coated stent based on a cobalt-chromium platform is safe in patients with clinically significant stenosis, according to a study published online August 26, 2015, ahead of print in Catheterization and Cardiovascular Interventions.

The OPTIMAX stent (Hexacath; Paris, France) is a thin-strut iteration of an earlier device with the same biocompatible coating that over the past decade has shown satisfactory outcomes in observational and randomized studies. But instead of having a stainless steel platform, the novel stent is made of cobalt-chromium, which has a superior radial strength, and features a helicoidal design that provides flexibility and conformability.

For this first-in-human study, Pasi P. Karjalainen, MD, PhD, of Satakunta Central Hospital (Pori, Finland), and colleagues enrolled 224 consecutive patients (mean age 67 years; 75% men) with symptomatic CAD and at least 50% diameter stenosis of a de novo lesion at a single center from January to July 2013. The majority (62.1%) of patients presented with ACS, and radial access was used in 92% of procedures. Most lesions (79.9%) were complex and postdilatation was performed in 78.1%. Heparin was the main antithrombin used, but bivalirudin was given in 11.2%.

Procedural and clinical success were achieved in all patients, and clinical follow-up at 12 months was available in 99.6%.

The incidence of 12-month MACE (cardiac death, nonfatal MI, or ischemia-driven TLR) was 6.3%. Three patients died of cardiac causes and 7 each had a nonfatal MI or ischemia-driven TLR. There were no instances of stent thrombosis.

Not the Only Option for Improving Biocompatibility

The study demonstrates “an adequate 12-month clinical outcome in patients with de novo coronary lesions,” the study authors write, cautioning that the results are only hypothesis-generating. “Multicenter studies of larger sample size and longer follow-up are needed to draw more solid conclusions,” they add “Moreover, in this first-in-man study, stents were deployed in de novo lesions, which do not reflect real-world practice. Additionally, a comparator group is needed for direct comparison of clinical outcome between the different stent designs.”

In an email interview with TCTMD, David E. Kandzari, MD, of Piedmont Heart Institute (Atlanta, GA), said, “If the intent of this coating is to improve biocompatibility, additional mechanistic studies such as assessment of strut coverage and development (and resolution) of incomplete apposition by imaging (such as OCT) and angiographic follow-up would be insightful—and would be useful in studies with more limited sample size.”

The study authors report that the ongoing TIDES-OCT study is examining “the vascular tissue response to the OPTIMAX stent vs another everolimus-eluting stent (PROMUS Element) with [OCT at 2 months]. Preliminary results suggest earlier and more adequate neointimal coverage associated with the OPTIMAX… but with significant neointimal hyperplasia.” Additionally, the OPTIMAX-QCA study will report on the 6-month late-loss of the device, they report.

OPTIMAX is “not the only stent to include a coating intended to improve biocompatibility,” Dr. Kandzari noted, citing the Osiro DES (Biotronik; Berlin, Germany) as an example—that device, which is currently being studied in a US pivotal trial, has a silicon carbide coating in addition to the drug sirolimus and a bioresorbable polymer.

“Presumably, the purpose of this technology would be to combine with drug elution,” he observed. “But as with all new DES technologies, demonstration of how outcomes with this stent type could provide additional improvement in outcomes above and beyond existing DES today is challenging.”

Source: 
Karjalainen PP, Mikkelsson J, Paana T, Nammas W. Clinical outcome of titanium-nitride-oxide-coated cobalt-chromium stents in patients with de novo coronary lesions: 12-month results of the OPTIMAX first-in-man study. Cath Cardiovasc Interv. 2015;Epub ahead of print.

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