Different Factors Linked to Early, Late Mortality with CoreValve TAVI

Results of a multicenter registry study suggest that transcatheter aortic valve implantation (TAVI) with the CoreValve system provides sustained clinical benefits with acceptable mortality up to 1 year in patients with severe symptomatic aortic stenosis at high risk for surgery. The study, published online January 10, 2011, ahead of print in Circulation, also shows that while procedure-related factors affect early mortality, comorbidities and paravalvular leakage are the major contributors to longer-term mortality.

Corrado Tamburino, MD, PhD, of Ferrarotto Hospital (Catania, Italy), and colleagues examined data from 663 consecutive patients undergoing TAVI with the third-generation 18-Fr CoreValve Revalving System (Medtronic, Minneapolis, MN) at 14 Italian centers from June 2007 to December 2009. One-year clinical follow-up was available in 94% of patients.

Predictors of Early and Late Mortality

Procedural success was high at 98%, with an intraprocedural mortality of 0.9%. In all, 107 patients died during follow-up: 34% within 30 days and another 53% later within the first year. The remaining 13% died after 1 year. The cumulative incidence of mortality was 5.4% at 30 days, 12.2% at 6 months, and 15.0% at 1 year. Cumulative incidence of mortality initially rose steeply with 25% of cases occurring within 14 days, followed by an almost linear increase in the remaining events up to 1 year.

EuroScore showed a weak ability to predict the risk of 30-day and 1-year mortality. The mean logistic EuroScore was basically equivalent for patients who died vs. survived (24.9 ± 15.1% vs. 22.6 ± 13.4%; P = 0.13). The best discriminative cut-off value of the logistic EuroScore was 21 for both 30-day (sensitivity 67%, specificity 56%) and 1-year mortality (sensitivity 57%, specificity 55%).

Multivariate analysis identified separate sets of independent predictors of early and late mortality (tables 1 and 2).

Table 1. Predictors of Early Mortality

 

Table 2. Predictors of Late Mortality

A substantial improvement in NYHA functional class was observed at 30 days and 1 year, with most patients in NYHA class I or II at each time point regardless of baseline functional class.

Paravalvular regurgitation after successful TAVI was common but was considered trace to mild in the vast majority of cases. Conversely, valvular regurgitation was almost entirely absent or mild and no structural valve deterioration was seen.

Consistent with Prior Studies

Dr. Tamburino and colleagues say the 30-day mortality seen in their study compares favorably with the 7% to 14% rates reported in earlier experiences with the third-generation CoreValve device.

In an e-mail communication with TCTMD, study coauthor Davide Capodanno, MD, also of Ferrarotto Hospital, said the outcomes seen in this real-world registry “are consistent with what we have already observed with the Edwards Sapien device. Another important point is that while early mortality is mainly related to the procedure itself, long-term mortality seems more affected by comorbidities and by suboptimal TAVI results.”

He added that “these findings suggest that in future, once the long-term safety and durability of TAVI results are demonstrated, a relaxation [of the restrictions on] the present indications could achieve even better results.”

Moving Ahead, but Cautiously

However, in an editorial accompanying the study, Philipp Kahlert, MD, and Raimund Erbel, MD, of the West German Heart Center Essen (Essen, Germany), say caution and enthusiasm must be carefully balanced.

“TAVI remains a complex and technically demanding procedure that requires advanced catheter skills and intensive training,” they write. “Moreover, TAVI is still associated with some procedural complications that will need to be further reduced in the future to improve procedural outcome.”

While they agree the Italian registry results suggest that TAVI might yield even better long-term results in lower-risk patients, they conclude that TAVI must first be evaluated to determine if it is comparable to surgery in a low-risk population.

According to Drs. Kahlert and Erbel, “the current registry data suggest that such clinical trials are worthwhile. Meanwhile, TAVI should be restricted to appropriate carefully selected patients treated by a trained and dedicated multidisciplinary team.”

One such trial that is ongoing is the randomized, controlled SURTAVI study, which also involves the CoreValve device and includes intermediate-risk patients. “This trial could give us the evidence needed to offer TAVI to a larger population of patients with symptomatic severe aortic stenosis,” Dr. Capodanno said.

Study Details

General anesthesia was used at the beginning of the experience and later replaced by local anesthesia and mild sedation. Depending on the size and condition of the iliofemoral arteries, patients were selected for the femoral (n = 599) or the subclavian (n = 64) approach.

All patients received aspirin (100 mg) before the procedure, and lifelong daily aspirin thereafter. A loading dose of clopidogrel (300 mg) was administered the day before the procedure followed by 75 mg daily for 3 to 6 months. During the intervention, unfractionated heparin (100 UI/kg) was administered to achieve an activated clotting time of 200 to 250 seconds for the duration of the procedure.

 

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Sources:
1. Tamburino C, Capodanno D, Ramondo A, et al. Incidence and predictors of early and late mortality after transcatheter aortic valve implantation in 663 patients with severe aortic stenosis. Circulation. 2011;Epub ahead of print.

2. Kahlert P, Erbel R. Transcatheter aortic valve implantation in the era after commercialization: Quo vadis in the real world? Circulation. 2011;Epub ahead of print.

 

 

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