TAVI with CoreValve Effective, Safe at 2-Years, Though Mortality a Concern

Download this article's Factoid (PDF & PPT for Gold Subscribers)

Patients who underwent transcatheter aortic valve implantation (TAVI) with the CoreValve self-expanding valve prosthesis for the treatment of severe aortic stenosis obtained sustained clinical benefits at 2-year follow-up, with no structural valve deterioration or change in hemodynamic status, though mortality was somewhat high. The study results were published in the April 19, 2011, issue of the Journal of the American College of Cardiology.

The prospective multicenter study, led by Lutz Buellesfeld, MD, of Bern University Hospital (Bern, Switzerland), provides the longest follow-up data to date for TAVI using the 18-Fr CoreValve device (Medtronic, Minneapolis, MN). The study evaluated the device’s safety and efficacy in 126 patients with severe aortic valve stenosis treated between 2006 and 2008 at 9 centers.

In these patients, all of whom were at moderate or high surgical risk, the TAVI procedure had a technical success rate of 83.1% and a procedural success rate of 72.6%. The overall MACCE rate (all-cause death, MI, emergent cardiac surgery or repeat PCI, and stroke) nearly doubled between 30-day and 2-year follow-up. Similarly, the researchers observed a more than twofold increase in all-cause mortality over the same time frame (table 1).

Table 1. Outcomes in Patients Undergoing TAVI

^a All-cause death, MI, emergent cardiac surgery or repeat PCI, and stroke.

Risk for surgical aortic valve replacement was determined using a retrospective risk stratification performed by 2 independent experts in aortic valve surgery. Fifty-four patients were classified as moderate surgical risk, 51 as high-risk operable, and 21 as high-risk inoperable. Although no major differences in 30-day all-cause mortality were observed between the subgroups, by 2-year follow-up high-risk patients had significantly increased mortality over moderate-risk patients (P = 0.04; table 2).

Table 2. All-Cause Mortality by Surgical Risk Subgroup

The researchers reported almost no change in hemodynamic status, with a mean gradient of 9 ± 3.4 mm Hg at 2 years compared with 8.5 ± 2.5 mm Hg at 30 days. At 2 years, only 1 case of endocarditis was reported, and there were no reports of structural valve deterioration, frame fractures, or valve migrations.

Early TAVI Experience

“The clinical significance of these results is difficult to determine, because they are from an early TAVI experience,” Susheel K. Kodali, MD, of Columbia University Medical Center (New York, NY), told TCTMD in a telephone interview. “This experience was from 2006 to 2008, which was very early in the learning curve.”

In the paper’s discussion section, the researchers agree, attributing the relatively low procedural success and increased mortality to learning curve and early technological issues.

“The procedural success rate of only 73% compared with reported rates of 90% to 97% in more recent studies is related to learning phase factors as well as a very conservative definition used in this study requiring MACCE-free in-hospital survival, without which the technical success rate was 83%,” Dr. Buellesfeld and colleagues write.

Comparison with PARTNER Trial

Dr. Kodali pointed out that although the heightened mortality may be partially explained, it is still a concern given the patient population enrolled in this trial. “Almost 40% of the patients in this trial were classified as moderate risk, which is very different from the recently presented PARTNER trial, where all patients by definition were high risk,” he said.

Just last week at the American College of Cardiology Scientific Sessions/i2 Summit in New Orleans, LA, results from cohort A of the PARTNER trial, which enrolled high-risk operable patients to undergo TAVI with the Edwards Sapien aortic valve system (Edwards Lifesciences, Irvine, CA), indicated a 30-day mortality of 3.4% for the TAVI procedure.

“Regardless of the methods used for surgical assessment in the current trial, it is mostly a moderate-risk surgical patient population,” Dr. Kodali said. “In that setting, the mortality reported here is very high.”

Moving Forward

The researchers reported no difference in cardiac death between the moderate- and high-risk groups. However, patients classified as high risk likely had higher all-cause mortality due to noncardiac comorbidities, “indicating that high-risk patients do not have a higher likelihood of dying for procedural or valve-related reasons but for reasons originating from their preexisting comorbidities,” they note.

Dr. Kodali said that high all-cause mortality points to the type of patient that is undergoing these procedures. “Hopefully, as we get to a lower-risk patient population we will see those curves flattening out early and maintaining a continuous decline.”

Despite the high mortality, Dr. Kodali characterized the reporting of these long-term results as a step in the right direction. “In terms of long-term follow-up, I think these results are great,” he said. “We need more studies that have long-term follow-up: 2 years, 5 years, and beyond.”

Study Details

The mean age of patients enrolled in the study was 82 years; 42.9% were men. The procedure was performed via femoral access in all but 2 patients.

Source:

Buellesfeld K, Gerckens U, Schuler G, et al. Two-year follow-up of patients undergoing transcatheter aortic valve implantation using a self-expanding valve prosthesis. J Am Coll Cardiol. 2011;57:1650-1657.

Related Stories:

• PARTNER: In High-Risk Surgical Candidates, TAVI Proves Just as Effective
• PARTNER: TAVI Cost Effective Compared with Standard Care