STS: Stentless Valves Not Hemodynamically Superior To Stented Valves In Aortic Valve Replacement

Stentless valves do not produce hemodynamically superior results over those provided by the more traditional stented valves, according to results from a randomized, prospective trial presented at the 37th annual meeting of The Society of Thoracic Surgeons.

For the trial, 53 patients undergoing aortic valve replacement between the years 1996 and 1999 received the stented C-E pericardial (CE) valve, and 46 patients received the Toronto Stentless Porcine (SPV) valve. Patients were matched for age, gender and New York Heart Association class, the majority being in class 3 and 4, although ejection fractions were reasonably well preserved at between 40 to 54 percent. Approximately 80 percent of both groups presented with aortic stenosis, and the incidence of both coronary artery disease as well as hypertension was also similar in both groups.

As presented by Dr. Gideon Cohen, fellow, division of cardiovascular surgery, Sunnybrook and Women’s College Health Sciences Centre, reassessment of left ventricular mass (LVM) at three and 12 months follow-up showed significant but virtually identical degrees of regression in both groups. At three months, LVM had regressed by 14.6 g/m2 for the CE group and by 15.3 g/m2 for the SPV groups.

At 12 months, LMV had regressed by 22.3 g/m2 in the CE group and 23.8 g/m2 in the SPV group. There was also no difference between groups in changes in the mean gradient at the end of 12 months either. In the CE group, the mean gradient dropped from 47.9 mmHg to 6.6 mmHg at one year, and in the SPV group, the mean gradient dropped from 49.1 mmHg to 5.9 mmHg at one year. Changes in the Duke Activity Status Index, which is a disease-specific quality of life index, again assessed at three and 12 months follow-up, showed significant improvements in both groups from baseline, but no superiority in either group, Dr. Cohen added.

Based on the manufacturers’ labeled valve size, researchers also found a statistically significant difference in the median implanted valve sizes at 22.9 mm in the CE group, and 26.3 mm in the SPV group. “But when we looked at the actual valve size based on internal diameter, there was no difference between the two groups, with median internal diameters of 21.9 mm for the CE valves, and 22.3 mm for the SPV valves,” Dr. Cohen said in an interview with Doctor’s Guide, adding:

“Both of these valves are exceptional valves and it may turn out the stentless valve is more durable that the CE valve, but we are misleading ourselves thinking that the stentless valve is superior because of the sizing issue,” Dr. Cohen said.

The stentless valve was developed by Toronto cardiologist, Dr. Tirone David to enable implantation of a valve one to three sizes larger than would otherwise be possible with conventional stented valves, thereby improving the area available for flow.