Percutaneous Aortic Valve Replacement Shown Feasible

By Robert Finn 

SCOTTSDALE, ARIZ. -- An endovascular approach to aortic valve replacement is feasible, according to the results of a preliminary study presented by Dr. Roy K. Greenberg at an international congress on endovascular interventions sponsored by the Arizona Heart Institute.

Of 54 high-risk patients who underwent the procedure, 4 (7.4%) died in the hospital and another 4 died within 30 days. While 15% may seem at first glance to be a relatively high death rate, it is comparable with the death rate one would expect of unoperated high-risk patients, said Dr. Greenberg of the department of vascular surgery at the Cleveland Clinic Foundation.

In 2006 there were about 150,000 surgical aortic valve replacements worldwide, compared with only 380 patients treated through a percutaneous approach.

"We need a less invasive option, because these patients are sick, and many of them are not considered good operative candidates," Dr. Greenberg said.

FIRST BALLOON-DILATE THE STENOTIC VALVE; THEN PLACE A BALLOON-EXPANDABLE STENT WITH A TISSUE VALVE WITHIN THE AORTIC VALVE.

The mean age of patients in the study was 82.4, and 18% of the patients were aged older than 90 years. They all had multiple risk factors. For example, 20 had left ventricular ejection fractions of less than 40%, and almost half had had prior coronary artery bypass grafts. These patients were not considered candidates for surgery. Their mean euroSCORE was 33.1, and their mean STS mortality risk level was 12.8.

Physicians gained access by the femoral route in 42 of the patients and by the retroperitoneal route in 9; they were unable to gain access in 3. Of the 51 patients in which access was successful, subsequent deployment was successful in 47 and unsuccessful in 4.

Throughout the follow-up period there were no myocardial infarctions, no reoperations for valve failure, and no postprocedure device migrations. There were five neurologic events, including one major stroke, three minor strokes, and one subarachnoid hemorrhage. There were seven vascular complications, including five iliac ruptures and two unplanned iliofemoral grafts.

Dr. Greenberg described the procedure as "not terribly complicated." The general strategy is first to balloon-dilate the stenotic aortic valve, then to place a balloon-expandable stent within the aortic valve. That stent contains a tissue valve within it.

At the beginning of the procedure a pacemaker must be inserted into the right ventricle. This allows the surgical team to rapid-pace the heart (to 180-220 beats per minute), and provides for a defined period of essentially no flow during which the valve can be deployed. The procedure is done in conjunction with transesophageal echocardiography. After valve deployment, the team obtains an angiogram, including specific angiography of the coronary arteries, to ensure that there were no problems.

"There is a tendency for the valves to go from a sclerotic valve to an incompetent valve [as a result of the procedure], and the data from the preliminary study suggest that this occurs in a lot of patients, but the amount of incompetence that's created is usually quite small," Dr. Greenberg said. "Almost all patients demonstrated improvement in left ventricular ejection fraction, which is ultimately the goal of this, to improve their functional status. And all the patients really improved in terms of their quality of life."

Dr. Greenberg disclosed grants and research support from several device manufacturers, but he said that none involved percutaneous aortic grafts.