ADVERTORIAL: “We are now at a new era of TAVI where we have very high rates of device success”

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Azeem Latib

CAUTION: The ACURATE neo aortic valve system is CE marked. In the USA, it is an investigational device—limited by US law to investigational use only;
not available for sale. The ACURATE neo2 aortic valve system is an investigational device only; not available for sale. Boston Scientific sponsored this advertorial.

At the 2018 Transcatheter Cardiovascular Therapeutics (TCT) meeting (21–25 September, San Diego, USA), Azeem Latib (IRCCS San Raffaele Scientific Institute, Milan, Italy) reported that the NEOPRO Registry shows that both ACURATE neo™ (“NEO”, Boston Scientific) and CoreValve Evolut™ PRO (“PRO”, Medtronic) are associated with a high rate of device success and good clinical outcomes.1 These results, according to Latib, indicate that we are now at a stage where “we have really good valves” and can start to choose a transcatheter aortic valve implantation (TAVI) device that is most appropriate for a patient’s anatomy.

Prior to the NEOPRO Registry, data for direct valve-to-valve comparisons were sparse. Additionally, of the data that are available, the comparisons feature older-generation TAVI devices—such as SAPIEN XT (Edwards Lifesciences) or CoreValve (Medtronic). Therefore, Latib and colleagues wanted to review newer transcatheter heart valves for which comparison data were not available. “We looked at Boston Scientific’s ACURATE neo and the latest generation of Medtronic’s CoreValve (Evolut PRO),” Latib tells Cardiovascular News. He notes that an ongoing randomised controlled trial (SCOPE II) is already comparing ACURATE neo with both the earlier iteration CoreValve Evolut R and the new Evolut PRO. As SCOPE II is a randomised controlled trial and NEOPRO is a registry, the studies will provide different insights into how the two valves compare. Registry data, Latib explains, are valuable because they reflect every day practice, and he comments: “Sometimes, randomised controlled trials are restrictive because of their inclusion and exclusion criteria. We always have to be sure that in clinical practice, we can produce similar outcomes to those seen in trials. Hence, the need for real-world data”.

In the NEOPRO Registry, Latib et al reviewed data for 1,551 patients who underwent TAVI with either ACURATE neo or Evolut PRO at 24 centres in Europe, Canada, and Latin America between January 2012 and March 2018. Reflecting that Evolut PRO is a latest-generation device and, thus, has not been on the market for as long as ACURATE neo, substantially fewer patients were implanted with this device: 288 vs. 1,263 for ACURATE neo. That Evolut PRO is a latest-generation device may explain why operators tended to use the valve in more complex patients than they did the ACURATE neo. For example, significantly more Evolut PRO patients had severe aortic valve calcification (p<0.001 for the comparison).

Subtle differences in overall cohort

Acurate neo

The primary endpoint of the NEOPRO study was the rate of device success according to Valve Academic Research Consortium (VARC-2) criteria and was not significantly different between groups: 92% for ACURATE neo vs. 90.7% for Evolut PRO. However, the rate of the VARC-2 30-day safety composite endpoint (a secondary endpoint) was significantly higher in patients who received ACURATE neo: 16.4% vs. 10.9% for Evolut PRO (p=0.025). This finding was driven by a significantly higher rate of all vascular complications due to a higher rate of minor bleeding with ACURATE neo (17.1% vs. 11.6%, respectively; p=0.025).

According to Latib, vascular complications may be higher with ACURATE neo because its delivery system has a higher French size than the one for Evolut PRO (18F outer diameter vs. 16F, respectively) and was used with older generation introducer sheaths. The effects of this higher French size, though, could potentially be mitigated with the new 14F iSLEEVE™ expandable introducer sheath (Boston Scientific). Latib observes that this sheath was not available when he and his colleagues conducted the NEOPRO registry and he is “convinced” that the difference in vascular complications between ACURATE neo and Evolut PRO “would have disappeared” had the new sheath been used. “The 14F iSLEEVE is an expandable sleeve, which reduces the French size to 14F. If you put in a smaller sheath, you make a smaller hole in the artery. We know that with all interventional cardiology procedures, the bigger the sheath is, the bigger the hole, the more patients bleed,” he explains.

Another notable difference between ACURATE neo and Evolut PRO in NEOPRO, says Latib, is the difference in pacemaker rates: 8.8% vs. 13.2% for Evolut PRO (p=0.045). He comments that “one of the things” that is reassuring about ACURATE neo is that it has a “single digit” pacemaker rate, adding that there are two possible reasons that explain why the pacemaker rate was better with the valve—lower radial strength and, more importantly, depth of implantation. “One of the variables that we now know affects pacemaker rates is how deep a valve is implanted into the left ventricular outflow tract. The deeper the valves goes, the higher the risk of requiring a pacemaker because it is closer to the atrioventricular node. With ACURATE neo, the implantation is always at the same level. With Evolut PRO, it is more dependent on the operator trying to get a higher implantation,” Latib states.

He comments that, in the registry, the rates of moderate paravalvular leak, “which is what we really care about”, were low and “almost identical” for the two devices (5.1 for ACURATE neo. vs. 5.4 for Evolut PRO). However, more patients in the Evolut PRO group had trace/none paravalvular leak than for the ACURATE neo group. While the rates of paravalvular leak with ACURATE neo were low, they may further reduce with the next-generation device ACURATE neo2™. This device has a higher pericardial skirt and this should reduce the rate of paravalvular leak, but, as Latib observes, further data are needed before this can be ascertained. Initial results from the CE-mark study for ACURATE neo2 do show 97% of patients had mild or no/trace paravalvular leak at 30 days (no patients had more than moderate paravalvular leak), but these findings need to be confirmed.2

Comparable outcomes in propensity-matched analysis

As mentioned, the Evolut PRO valve tended to be implanted in more complex patients than the ACURATE neo valve. Latib et al felt that this led to certain differences (such as more patients having more severe aortic calcification in the Evolut PRO group) between cohorts that could have affected the results. Latib explains: “When we saw these differences, we realised it would not be appropriate to just do an analysis of the entire population. We also needed to do an analysis that corrected for some of these differences. Therefore, we performed a propensity-matched analysis.”

In this propensity-matched analysis, there were no significant differences in any of the outcomes between cohorts (device success was still high in both groups), including vascular complications and pacemaker rates. Interestingly, the pacemaker rate increased to 11% in the ACURATE neo cohort (vs. 12.8% for Evolut PRO). Latib says he was “not surprised” that the rate increased in this cohort because the patients in the propensity-matched analysis were more complex with more calcification (i.e. the higher pacemaker rate relates to the characteristics of the patient rather than the valve). He comments: “Subtle differences in procedural characteristics [pre and post dilatation was higher with ACURATE neo] and clinical outcomes highlight the different design features of the two valves. After adjustment for potential confounders, short-term outcomes were similar between both devices.”

Conclusion

Latib thinks that the results of the NEOPRO Registry, along with those of other TAVI studies, show that “we are now in a new era of TAVI where we have very high rates of device success with much lower rates of paravalvular leakage and good clinical outcomes”. He suggests that the availability of several valves with good clinical outcomes on the market means that we are reaching a point at which we can start “tailoring the valves to the patient”, noting an experienced centre (such as his) can now use the valve that is most appropriate for the patient’s anatomy.

References

  1. Latib A. NEOPRO Registry. TCT 2018 presentation.
  2. Kim WK, et al. PCR Valves 2018 presentation.

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