VDM Speaks with Srinivas Iyengar, MD, FACC, Primary Operator and Site Investigator for the OSPREY Trial


Submitted on Tue, 01/04/2011 - 14:10

Srinivas Iyengar, MD, FACC

You recently performed the first SFA implantation of the Misago™ stent as an investigator in the recently initiated OSPREY (Occlusive/ Stenotic Peripheral arteryREvascularization StudY) trial. What was your experience with this stent? What was the patient’s history and lesion profile?

The case involved a male patient in his 60s with a history of smoking, hypertension and bilateral claudication. He was treated with medical and exercise therapy without significant improvement. It was determined that he had significant peripheral vascular disease (PVD) via outpatient noninvasive testing. Angiography was performed which revealed ostial left superficial femoral artery (SFA) disease (not suitable for stenting) and right mid-SFA disease (suitable for stenting). His right SFA was treated with percutaneous transluminal angioplasty (PTA). The lesion characteristics of the right SFA met the specifications for the trial. The procedure was performed successfully with the Misago stent (Terumo Medical Corp., Somerset, New Jersey), deployment was simple and went smoother as a rapid-exchange stent as opposed to an over-the-wire one.

Describe the OSPREY trial: inclusion and exclusion criteria, primary endpoints, number of patients and centers participating.

The Occlusive/Stenotic Peripheral artery REvascularization StudY (OSPREY), reviewed under a pilot program of the U.S. Food and Drug Administration and Japan’s regulatory agencies MHLW-PMDA, will evaluate the safety and efficacy of the Misago™ Peripheral Self-expanding Stent System for use in the SFA.

The landmark OSPREY clinical trial will simultaneously enroll patients in the U.S. and Japan. Referred to as “Medical Device Collaborative Consultation and Review of Premarketing Applications” under the larger Harmonization by Doing (HBD) initiative, the OSPREY trial was selected as one of two projects to pilot this approach, which is intended to shorten the gap between product approvals in these two significant world healthcare markets.

The pilot program is a cooperative effort led by the Terumo Corporation based in Tokyo, Japan, and Terumo Medical Corporation, a U.S.-based subsidiary of Terumo Corporation. In the U.S., OSPREY is a single-arm, multicenter, nonrandomized prospective clinical trial for the treatment of atherosclerotic stenoses and occlusions of the SFA. In Japan, there are two arms of the study: 50 patients receiving the Misago Stent System and 50 patients receiving PTA.

The primary endpoints of the U.S. study are:

• Primary stent patency rate at 1 year as confirmed by duplex ultrasound or angiography. • Freedom from major adverse events within 30 days of the procedure, which would result in target lesion revascularization, amputation of the treated limb or death.

The study will include up to 350 patients, a maximum of 250 patients in up to 30 centers in the U.S. and 100 patients in Japan. Japan received regulatory approval in 2009, while the U.S. study was approved in 2010. Both studies have started to enroll patients.

Bradenton Cardiology Center in Bradenton, Florida, was the first U.S. clinical center to complete an implantation as part of this landmark study.

What type of disease is the Misago stent designed to treat?

The Misago Stent System is designed to treat patients with peripheral artery disease (PAD). According to the American Heart Association, approximately 8 million Americans suffer from PAD. Unfortunately, PAD is often undiagnosed by healthcare professionals because the symptoms can be mistaken for some other condition. The most common symptoms are cramping, pain or tiredness in the leg or hip muscles while walking or climbing stairs. Typically, the pain goes away with rest, but flares up again when walking resumes. Most cases of PAD can be managed with lifestyle changes and medical therapy; however, left untreated, this condition can lead to gangrene and amputation of the affected limb.

Describe the Misago stent and what makes it unique.

The unique design distributes the dynamic SFA stress loads throughout the stent’s struts, providing not only flexibility, but also durability against bending, compression and torsion. The Misago Stent System features the first rapid-exchange (RX) delivery catheter for use in the SFA.

What do you anticipate the OSPREY trial results will show?

It is difficult to determine the end results since we are just getting started. We are hoping for equal or less restenosis than achieved with other stents. It is too early to tell without long-term data and follow-up with patients.

Will the Misago stent system change the way SFA stenoses are treated?

Possibly. The rapid-exchange system will make it easier since the stent can operate along shorter guidewires. The stent also is simply deployed with less deliverability challenges.

Is it currently approved for use in other countries?

The Misago Stent System is manufactured in Japan by Terumo Corporation and has been available in Europe since November 2007. To date, approximately 9,000 femoral-popliteal units have been sold (7,500 patients treated).

How do you see the treatment of SFA stenosis evolving over the next decade or so?

I eventually see this evolving from the use of bare-metal stents, such as this, to drug-coated stents and balloons.


Dr. Iyengar was born and raised in New Jersey. He attended Rutgers University followed by medical school at Ross University. He completed his Internal Medicine training at the Jewish Hospital/University of Cincinnati, which included a year as Chief Resident. This was followed by a four-year fellowship at the Ohio State University in cardiovascular medicine which included a self-obtained grant-supported year in Heart Failure/Cardiac Transplantation research. After completing this fellowship, Dr. Iyengar continued on to a two-year advanced fellowship in Interventional Cardiology and Peripheral Endovascular training at Columbia University. Dr. Iyengar has first-authored over twenty manuscripts in such journals such as Circulation, Journal of Invasive Cardiology, and Journal of Heart and Lung Transplantation. He has also written a number of book chapters and on-line presentations, as well as actively contributing and participating in national medical meetings and live-case presentations. He is board-certified in Internal Medicine, Cardiovascular Medicine, and Interventional Cardiology. His primary interest revolves around the use of percutaneous endovascular therapies and their further development in both the academic and clinical settings.