Innovative Aortic Valve Replacement

Mercy Heart and Vascular Hospital offers TAVR for high-risk patients

The Mercy Heart and Vascular Hospital multidisciplinary HEART VALVE team was the first community-based hospital staff in Greater St. Louis to perform transcatheter aortic valve replacement (TAVR), an innovative procedure to replace narrowed or diseased aortic heart valves non-surgically using a catheter.

Cardiologist Anthony Sonn, MD, director of the TAVR program at Mercy Heart and Vascular Hospital, said the lifesaving aortic valve replacement without open heart surgery was performed on three patients in May, with two patients scheduled for the procedure at press time.  

“The procedure is easier on patients than traditional surgery and recovery time is greatly diminished,” he said. “TAVR will improve the quality of life and extend life expectancy for those who are not able to withstand open heart surgery.” 

Several years ago, when Edwards Lifesciences, maker of The SAPIEN Transcatheter Heart Valve, was running clinical trials at various public sites around the country, such as Barnes-Jewish Hospital, a part of Washington University School of Medicine, Sonn and heart surgeon Jack Marbarger, chief of cardiothoracic surgery at Mercy, traveled to Edwards’ headquarters in California to become more familiar with the technology.

“We knew the only way a TAVR program was going to be successful was by taking a true multidisciplinary approach,” said Sonn. “As long as cardiologists and cardiac surgeons work collaboratively, the patients will benefit the most and have a successful outcome. That’s how you build a successful program.”

Making Preparations

With nine floors dedicated to heart and vascular services, and 96 private patient rooms, on-site laboratories for diagnosing and treating cardiovascular illness, and operating rooms dedicated exclusively to heart and vascular care, the Joint Commission – and Society of Chest Pain – accredited Mercy Heart and Vascular Hospital, opened on New Ballas Road in west St. Louis in 2006. The specialty hospital is the first institution of its kind in the region devoted exclusively to the prevention, detection and treatment of heart and vascular diseases. The comprehensive TAVR clinic opened last fall in preparation for training and performing the special procedure.

“For the past year or so, we’ve been combining consultative services together,” said Sonn. “We see patients as a group. We’re constantly evaluating patients through our clinic.”

The innovative technology involves a bovine heart valve stitched inside a stainless steel scaffold, or stent. The Edwards SAPIEN transcatheter heart valve is crimped down onto a catheter, which is then fed up through a patient’s femoral artery to the heart. A balloon temporarily inflates inside the stent, setting it in place and replacing the malfunctioning valve.

Many patients aren’t healthy or strong enough for traditional valve replacement surgery, which involves opening the patient’s chest and placing them on a heart/lung bypass machine during the valve replacement. With TAVR, Mercy specialists feed a catheter through a patient’s artery in the groin to their heart to replace the valve.

The collaborative environment creates a tenacious approach to the management of valvular heart disease and provides candidates with a significant benefit by shortening workup times and expediting the decision making process. Mercy also participates in the national TAVR registry to evaluate the risks, benefits, and changes in patient selection criteria, procedural performance, and device iteration.

Patient Selection

Nearly 1.5 million people in the United States suffer from aortic stenosis, a progressive disease affecting the aortic valve. Of those, approximately 250,000 suffer from severe aortic stenosis.

Selecting patients for the TAVR procedure is such an arduous process because of the rigid criteria to enroll high-risk and inoperable patients, said Sonn.

Mercy follows the guidelines jointly developed by the American Heart Association, American College of Cardiology (ACC) Foundation, American Association for Thoracic Surgery, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons, who herald the new TAVR device as “a fundamental change in the management of aortic valvular heart disease” by presenting an alternative approach to traditional surgical AVR in carefully selected patients.

Specifically, patients with prohibitive surgical risk defined as an estimated 50 percent or greater risk for mortality or irreversible morbidity at 30 days meet the criteria for TAVR patient selection. TAVR is not recommended for patients with an acceptable surgical risk for conventional surgical AVR, those with a known bicuspid aortic valve, failing bioprosthetic aortic valve, severe mitral annular calcification or severe mitral regurgitation, moderate valvular aortic stenosis, or severe aortic regurgitation and subaortic stenosis. Screening protocols of every TAVR evaluation include imaging data on aortic stenosis, ventricular function, and assessment for cognitive impairment.

The first step in the process of patient enrollment includes screening the patient to determine the severity of their aortic valve stenosis.

After the valve measurements are confirmed, the question of operative status must be addressed by surgical members of the team. Very strict requirements govern surgical inoperability. Next, patients undergo a litany of tests to review cardiac morphology, existence of coronary disease, size of the iliac vessels, and tests of exercise tolerance. TAVR nurse coordinator Jennifer Papin, RN, follows patients from referral to follow up. She organizes all testing and consultations in one place to make scheduling as convenient as possible for patients.

Once the pre-requisite work is completed, the patient is scheduled for the procedure, which takes place in Mercy’s hybrid operating suite. Cardiothoracic surgeons and interventional cardiologists perform the procedure together. Imaging specialists take real-time ultrasound images throughout the procedure.

Heart team members base a decision on TAVR candidates by seven predictive risk algorithms, including the two most common risk algorithms – Society of Thoracic Surgeons (STS) Score and Logistic EuroSCORE (LES). Experts agree the STS score is by far the most accurate and best available method for assessing risk and outcomes; LES is more accurate in lower-risk patients.

These parameters are based on a study of 67,000 valve procedures performed in the United States from 2002 to 2006 for the STS score, compared to the latest study dates for the LES score in 1995. A new version of the STS database went live on July 1, 2011, which now includes risk variables for liver disease, frailty and radiation. Linking clinical and administrative databases should allow heart team members to better analyze long-term outcomes.

“Right now, TAVR is FDA-approved only for patients who are non-operative candidates,” said Sonn. “It’s a work in progress, but I believe we’ll eventually see indications that will become wider for patients who are high risk.”