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COVER FEATURE in light of this procedure's safety and its proven benefi t in high-risk patients poorly suited for surgery," explains Dr. Pedersen. "What makes this procedure attractive is the ability to place, but not initially release, the clip across the regurgitant valve orifi ce via a percutaneous catheter under trans- esophageal echo guidance. After initial clip placement, the echocardiographer and operator determine the adequacy of mitral regurgitation reduction. If the clip fails, in spite of testing multiple sites, it is not deployed, and the patient can be referred for elective surgical repair." "Three-dimensional, echocardiographic imaging has given us much more precise information of the catheter's position with respect to the mitral valve," states Dr. Richard Bae, Director of Interventional Echocardiography. "It is useful in reducing the procedure time of these often lengthy cases. This offers a rationale for attempting the less invasive clip first. Again, my colleagues and I are not convinced that the clip is an equivalent fi rst option for degen- erative valves such as mitral valve prolapse, but see it playing a more significant role in functional mitral regurgitation, especially for those at higher surgical risk. I think that the use of the clip will grow signifi cantly following FDA approval. We are currently screening for these patients in an open-access, FDA-approved registry." "We have also begun percutaneously closing paravalvular leaks," explains Dr. Pedersen. "Between 1% and 3% of surgical valves develop a leak on the periphery of the artificial valve. If the leak results in heart failure or hemolytic anemia, the standard of care is to surgi- cally replace the valve. "This initial valve failure, however, is often caused by poor tissue milieu that will result in a 10% to 15% paravalvular leak recurrence following a second operation," Dr. Pedersen continues. "In addition, any repeat surgery carries a higher operative mortality. We use metallic mesh devices to plug these holes via transcatheter delivery systems, which have reported success rates of 70% to 80%. The structural complexity of these novel transcatheter procedures requires the combined expertise of a mul- tidisciplinary cardiac interventional team 10 | Twin Cities MD NEWS MDNEWS.COM PARTNER I I TRIAL CANDIDATES THE MHI VALVE Center welcomes qualifi ed candidates to participate in transcatheter research studies. Some of the relevant criteria for participation in the PARTNER II Trial include: + a combined morbidity mortality risk of 50%, assessed by two surgeons and a cardiologist + echocardiographic aortic valve parameters that include: − a 40 mm or greater mean gradient − a peak velocity of 4.0 meters per second or greater that includes advanced imaging experts. "The center is a truly multidisciplinary team. Currently, TAVI procedures are carried out in the presence of two interven- tional cardiologists, two cardiac surgeons, an interventional echocardiographer, an anesthesiologist and an on-call vascular surgeon, in addition to circulating nurses and scrub techs." "We foresee regional valve centers of excellence arising that will be the most qualifi ed and have the resources available to perform these technically demanding, complex valve procedures to ensure safe and effective outcomes," stresses Dr. Kshettry. "Preoperative advanced imaging and intraprocedural transesophageal echo with 3-D capability are essential," states Dr. Harris. "Our imaging subspecialists understand the structural complexities of these diseases. Their presence is necessary on the day of surgery to guide the surgeon through the procedure." At the MHI Valve Center, the team of surgeons and interventional, echo, CT and MRI imaging specialists meet weekly to discuss complex aortic valve cases for fi nal approval. The group evaluates whether a patient is a reasonable risk for surgery or a better candidate for the transcatheter approach. A formal presentation of candi- dates deemed appropriate for participation in the PARTNER II TAVI Trial is assembled and presented to a national forum twice weekly. Each week, the center receives fi ve to − a valve area of less than 0.8 cm2 valve index of <0.5 cm2 /m2 − iliofemoral arteries that are 7 mm or greater − a left ventricular ejection fraction of greater than 20% − bicuspid valves are excluded Physicians are invited to contact the MHI Valve Center at (612) 863-VALV (8258). or 10 referrals for potential participation in the PARTNER II Trial. Of those, one to two will qualify. "The most common reason for being disqualifi ed from the transfemoral delivery approach is severe disease in the iliofemoral arteries, which prevents delivery of these large catheters to the heart," says John Lesser, M.D., Director of Cardiovascular CT and MRI. "We are meticulous in our measure- ments of these arteries before approving patients to undergo TAVI." "Many of us believe that in 10 years, if longer term follow-up demonstrates equivalent valve durability, these transcath- eter procedures may become the treatment of choice," says Dr. Pedersen. "We see an opportunity with transcatheter proce- dures to offer a substantial percentage of high-risk patients an alternative treatment that has the potential to enhance their quality of life." n

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