German Data Show Impact of TAVR Introduction on Clinical Practice Patterns

In the years since the introduction of transcatheter aortic valve replacement (TAVR), data suggest that significant and reassuringly positive shifts appear to be occurring in patient selection as well as outcomes. 

In a study published in the December 17, 2015, issue of The New England Journal of Medicine, investigators led by Jochen Reinöhl, MD, of University of Freiburg (Freiburg, Germany), looked at all isolated TAVR and surgical aortic valve replacement (SAVR) performed in Germany over a 7-year period from 2007 to 2013.

During that time, the number of TAVR procedures increased from 144 in 2007 to 9,147 in 2013, while the number of SAVR procedures saw a slight decrease from 8,622 to 7,048. The total numbers of TAVR and SAVR cases were 32,581 and 55,992, respectively.

According to Reinöhl and colleagues, “the increase in the use of TAVR occurred to a substantial degree among patients who would have been unlikely to undergo surgery owing to their age and risk profile.”

The study also demonstrated that use of mechanical prostheses in SAVR declined dramatically, being reserved almost exclusively for patients < 75 years of age. The use of bioprosthetic implants, on the other hand, remained nearly unchanged. While both transfemoral and transapical TAVR increased over time in terms of absolute numbers, transfemoral TAVR far outpaced transapical, accounting for 74.3% of all TAVR cases performed in 2013. Compared with SAVR patients, those undergoing TAVR were older (mean age, 81.0 vs 70.2 years), and had higher estimated logistic EuroSCORE (mean, 22.4% vs 6.3%).

Positive Trends for Mortality

Overall, rates of in-hospital mortality for TAVR were two-fold greater than for SAVR (6.5% vs 2.9%; OR 2.41; P < .001), a difference that the researchers say probably reflects differences in preoperative risk based on logistic EuroSCORE. After adjustment for EuroSCORE, however, the odds ratio decreased “substantially” while remaining statistically significant (OR 1.30; P < .001).

While reductions in mortality occurred over time for both procedures, improvements were smaller for SAVR than for TAVR. By 2013, in-hospital mortality was equivalent at 4.4% for TAVR and SAVR among patients aged 80 to 84 years, despite EuroSCORE differences. For patients < 75 years of age, TAVR conferred lower in-hospital mortality than SAVR (1.4% vs. 5.5%).

Not surprisingly, need for permanent pacemaker was the most frequent complication of TAVR. Pacemaker, stroke, and overall rate of acute kidney injury (AKI) all were higher with TAVR than SAVR, while bleeding was more frequent with the latter.

Declines in complication rates were seen between 2007 and 2013 for bleeding, pacemaker implantation, stroke, and AKI with TAVR. Similar trends were seen for SAVR, with significant decreases in stroke, bleeding, and permanent pacemaker, but the rate of AKI with SAVR continued to increase (from 2.4% in 2007 to 3.8% in 2013).

Of the major complications, AKI was associated with the greatest increased risk of death, a relationship that stayed significant after adjustment for baseline characteristics, procedural details, and other complications. Stroke and bleeding also increased the adjusted risk of death, while permanent pacemaker implantation did not.

“During this period, a marked increase in the number of TAVR procedures occurred contemporaneously with a relatively small decrease in the number of [SAVR] procedures, primarily in the oldest patients and those at highest risk,” the study authors write. “Moreover, the proportion of TAVR procedures performed in the youngest patients (< 75 years of age) remained consistently low, and in all age groups, the estimated logistic EuroSCORE values were significantly higher in patients undergoing TAVR than in those undergoing [SAVR].”

Based on the data, Reinöhl and colleagues observe that TAVR’s decline in in-hospital mortality arose from a combination of factors, including a learning curve effect on procedural skills and improvements in patient selection and care, as well as advances in devices. For SAVR, they say, improvement in outcomes was probably due “in part to the shift from surgical replacement to TAVR for high-risk patients.”

Furthermore, they suggest that the decrease in permanent pacemaker implantation for TAVR “may reflect the more frequent use of balloon-expandable devices than self-expanding devices, but the data we obtained did not identify the type of device that was used in each procedure.” Declines in bleeding may be a consequence of lower-profile delivery systems and less frequent use of surgical cutdown for vascular access, they hypothesize.

Looking in the ‘Rear-View Mirror’

In an interview with TCTMD, Ted Feldman, MD, of NorthShore University HealthSystem (Evanston, Illinois), said the German database stands out from other registries and single-center reports due to the large volume of procedures it captures.

“We’ve known for many years that a large segment of high-risk [aortic stenosis] patients never got surgical AVR. At the beginning of the TAVR effort it was estimated that that population might be a third or half again as large as the surgical population, and I think that’s exactly what we see here,” he said. The slight decline in SAVR, he added, coupled with better mortality outcomes shows that “there clearly has been a welcome passing off of the higher-risk patients from surgery to TAVR.” This amounts to assurances that the balance of patient selection has been “very rational,” Feldman observed.

In addition to patient selection, he noted, the data also reflect how lower-profile devices have changed the TAVR landscape, although the change has come earlier to places such as Germany that have had the devices longer than the United States.

“I think the simplest conclusion from this is that these data should make clinicians optimistic that we are on the right path with the development of TAVR,” Feldman noted. “But this study doesn’t tell us anything about how things may look if we were treating lower-risk patients. So, to some extent it is a look in the rear-view mirror rather than a look to the horizon.”

Importantly, given the high rate of reimbursement for TAVR in Germany, the data reassuringly reflect “thoughtful practice,” he added.

Source: 
Reinöhl J, Kaier K, Reinecke H, et al. Effect of availability of transcatheter aortic-valve replacement on clinical practice. N Engl J Med. 2015; 373:2438-2447. 

Disclosures:

• The study was supported by internal funding from the Heart Center, Freiburg University. 
• Reinöhl reports receiving personal fees from Edwards Lifesciences and Direct Flow Medical. 

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