Successful FIH Transcaval TAVR Cases Presented at SCAI

May 29, 2014—The Society for Cardiovascular Angiography and Interventions (SCAI) announced the presentation of findings from the first-in-human (FIH) procedures using a transcaval approach for transcatheter aortic valve replacement (TAVR) with Medtronic, Inc.’s CoreValve device. Vikas Singh, MD, a cardiology fellow at the University of Miami in Florida, presented the study in a Best of the Best Oral Abstracts session at the SCAI 2014 scientific sessions in Las Vegas, Nevada.

According to SCAI, the study shows that this novel procedure, through taking advantage of the size and elasticity of the body’s major veins, is making it possible to use minimally invasive techniques to replace diseased aortic valves in patients whose arteries are too clogged with plaque to allow passage of large catheters. Generally, arteries are used to provide access for left heart procedures, like angioplasty and TAVR, whereas veins are used as access for right heart procedures, such as ablations for arrhythmias and closure of septal defects, noted the society.

This study describes the first experience in humans with this new technique to use veins to gain access to the aorta to perform TAVR using the CoreValve system as a replacement for a calcified, poorly functioning aortic valve in patients with no other treatment options.

In the SCAI press release, Dr. Singh commented, “We have initially performed these procedures in patients with no other access options, but we believe this approach will gain popularity in the future. Since it does not involve surgery, it could be a good choice whenever the femoral artery cannot be used because of extensive peripheral vascular disease.”

In the transcaval technique, the sheaths used in performing TAVR are threaded through a puncture in the femoral vein in the groin instead of through the usual access point, the femoral artery. Dr. Singh observed, “Veins are very distensible and compliant. That means we are able to use the large delivery sheaths without much difficulty.”

The investigators performed transcaval TAVR in three patients with severe obstruction of the aortic valve. The average age of the patients was 80 years, and they had extensive plaque buildup throughout their arteries. Such patients are often offered alternative transaortic or transapical options to perform TAVR, but these patients were not candidates for any of these. In addition, the patients were considered too high risk for open-chest surgery to replace the aortic valve.

The procedure was summarized in the SCAI announcement. To begin, a guidewire with a cautery device on its tip is threaded from the femoral vein in the groin into the inferior vena cava (IVC). In the abdomen, where the IVC runs right next to the aorta, the cautery device was used to burn a hole through both blood vessels, creating a connection between the venous and arterial systems to allow passage of a guidewire. A snare slender enough to fit through the plaque-filled femoral artery into the aorta was used to capture the guidewire and pull it into the aorta. All of the other tools, including the CoreValve, were then threaded through the femoral vein to the IVC and across the new passageway into the aorta. At that point, the CoreValve was advanced to the diseased aortic valve and deployed as in any other TAVR procedure.

When TAVR was complete, the interventional cardiologists sealed the connection created in the IVC and abdominal aorta using St. Jude Medical’s Amplatzer Muscular VSD occluder. This Amplatzer device, which is designed to seal congenital ventricular septal defects, is composed of two nitinol wire discs with a neck in between the discs. In the procedure, one disc is positioned in the aorta and the other disc in the IVC; these are sandwiched together, sealing the connection created between the two blood vessels.

Dr. Singh reported that the transcaval TAVR procedure was successful in all three patients, resulting in marked improvement in the size of the aortic valve opening and no serious complications. Equally important, the patients showed substantial improvement in their day-to-day physical abilities, increasing their New York Heart Association Functional Class score from an average of 3.3 to 1.3.

“The difference the patients experienced from before the procedure to after it can be likened to that between being short of breath with minimal activity and nearly bedbound to being able to go grocery shopping and do other daily errands,” concluded Dr. Singh. “Nevertheless, interventional cardiologists should be mindful of this approach, especially for patients with no arterial access. So far these procedures have been performed by a group of highly skilled operators, but as the technique gets more refined, there will be more widespread use of this approach.”