Thirty-day clinical outcomes from the FORWARD PRO international study of the Evolut Pro (Medtronic) self-expanding transcatheter aortic valve, published in EuroIntervention, have confirmed the safety and efficacy of the device with an external pericardial wrap.
Evolut Pro is a repositionable, self-expanding supra-annular valve within a Nitinol frame to treat aortic annuli diameters of 18–26mm. The device includes an outer porcine pericardial wrap, sutured to the inflow portion of the valve frame to diminish paravalvular leak (PVL) and to facilitate tissue ingrowth.
Study author Ganesh Manoharan (Royal Victoria Hospital, Belfast, UK) writes that initial use of the Evolut Pro valve in 60 patients in the US showed that 72.4% of patients had no or trace aortic regurgitation (AR) at 30 days, whilst maintaining the safety profile of the procedure. The FORWARD PRO study seeks to evaluate the clinical performance and safety of the Evolut Pro valve in a larger cohort of patients using standard clinical practice.
The study enrolled symptomatic patients with native aortic valve stenosis or a failed surgical aortic valve bioprosthesis requiring replacement, who were at high risk for surgery. The primary endpoint was the rate of all-cause mortality at 30 days compared with a pre-specified performance goal of 5.5% and secondary endpoints include the proportion of patients with mild aortic regurgitation at discharge compared with a pre-specified performance goal of 67.1%. A total of 638 patients enrolled in the study at 39 centres in 14 countries between February 2018 and January 2019, of which 629 underwent attempted implant.
Manoharan and colleagues write that results of the study showed a lower than expected all-cause mortality of 3.2%; a low disabling stroke rate of 2.9%; a low major vascular complication rate of 3% and favourable aortic valve haemodynamics, with an aortic valve gradient of 7.9±4.7 mmHg and EOA of 2.1±0.6cm2, and moderate or severe aortic regurgitation of 1.8%.
However, the pre-defined performance goal of no or trace aortic regurgitation (59.2%), as compared to the performance goal of 67.1%, was not met. Manoharan wrote that this is similar to a single centre report from Germany comparing 148 Evolut R valve patients with 74 Evolut PRO valve patients, but contrary to the findings of the smaller US Evolut PRO study, where initial experience in 60 patients demonstrated no or trace PVL in 72.4% of patients. Possible reasons for this difference, Manoharan notes, may include a degree annular calcification and distribution—the significantly larger and less selected cohort of patients would have included a more heterogeneous group of patients, with larger calcification burden, adversely impacting the PVL observed. He also noted that more patients in the previous study cohort underwent pre-dilation as compared to the present study (52% vs 34%) while the rate of post-dilation was similar (27% vs 31%), adding “perhaps pre-dilation improves device contact with the surrounding anatomy and resultant seal”. The addition of an external pericardial wrap on the Evolut Pro valve did not adversely affect the new post-TAVI pacemaker rate of 20.7%, Manoharan adds.
In conclusion, Manoharan and colleagues note that the 30-day results of the FORWARD PRO study support the safety and clinical effectiveness of the Evolut Pro device in treating symptomatic patients with severe aortic stenosis at intermediate, high or greater risk for surgical aortic valve replacement. “Longer term follow-up will be required to further evaluate these findings,” it is noted.