RHEIA - Transcatheter versus surgical aortic valve replacement in women with severe aortic stenosis

Reported from ESC Congress 2024

Why this study – the rationale/objective?

Subgroup analyses from trials of patients with aortic valve stenosis suggest that TAVI may be linked to superior outcomes as compared to surgical replacement in women. This hypothesis has not been tested to date in a dedicated trial.

The RHEIA trial was presented in a Hotline Session at ESC congress 2024 and reports on the outcomes of TAVI versus surgical treatment for severe aortic valve stenosis in an all-women population with any surgical risk status (except prohibitive).

How was it executed?

443 women with severe aortic valve stenosis (high or low gradient) were randomized 1:1 to either TAVI with a third-generation balloon-expandable system (Edwards Sapien, Sapien Ultra) using transfemoral access or surgical aortic valve replacement (Edwards Magna Ease, Intuityn Livanova Perceval).

Patients with bicuspid, unicuspid valves or non-calcified valves, as well as complex coronary artery disease or features increasing the risk of complications with TAVI or surgery were excluded.

48 centers from 12 European countries participated in the trial. The primary endpoint was a composite of all-cause mortality, stroke and re-hospitalization for valve- or procedure-related symptoms or worsening heart failure at 1 year.
The mean age of the patients was 73 years and the mean STS risk score was 2.1 %. 34 % - 39 % of patients were in NYHA class III or IV, and 19 % of patients had concomitant coronary artery disease.

In the surgical group, 27 % of patients were operated with a mini sternotomy and 7 % had a concomitant CABG. The majority of TAVI patients (63 % of total) were treated with the 26 mm valve, whereas the majority of surgical valves were 21 mm (34 %) and 23 mm (43 %).

What is the main result?

At one year, a significantly lower percentage of patients treated by TAVI met the primary composite endpoint, as compared to surgical replacement of the aortic valve (8.9 % for the TAVI group versus 15.6 % for the surgical group, p = 0.03), and this difference met the criteria for both non-inferiority and superiority.

The main driver of the difference in outcomes was the reduced re-hospitalisations for valve or procedure-related symptoms or worsening heart failure (4.8 % for TAVI versus 11.4 % for surgery, p = 0.02). Moreover, TAVI was associated with a lower rates of new-onset atrial fibrillation (3.3 % for TAVI versus 28.8 % for surgery, p < 0.001) and shorter hospitalisations (4 days for TAVI versus 9 days for surgery). However, the rate of pacemaker implantation were higher for TAVI (8.8 % for TAVI versus 2.9 % for surgery, p = 0.01).

Concerning valve hemodynamics, TAVI valves had higher mean gradients and lower effective orifice areas at 1 month and 1 year compared to surgical valves (mean gradients: 13.6 mm Hg versus 10.9 mm Hg at 1 month, p < 0.001 and 14.3 versus 11.7 mm Hg at 1 year, p < 0.001). Patient prosthesis mismatch rates at 30 days did not differ between groups, but TAVI resulted in higher rates of mild paravalvular aortic regurgitation (15.5 % for TAVI versus 2.4 % for surgery, p < 0.001).

Critical reading and the relevance for clinical practice

This is the first trial of TAVI versus surgical replacement of the aortic valve in an all-female population. As women have been frequently underrepresented in cardiology trials, the RHEIA trial sets the stage for dedicated trials for women in the structural field.

The reduction in re-hospitalisations with TAVI coupled with a shorter duration of initial hospitalization are translated in a better overall patient experience. However, this comes at the cost of higher pacemaker implantation rates and mild paravalvular aortic regurgitation, as was already known from previous TAVI trials in a mixed gender population.

Of note, the RHEIA trial was performed using only balloon-expandable valves, so the extrapolation of these results self-expandable platforms should be done with caution. Nonetheless, and in the aftermath of the SMART trial that showed that patients with small aortic annuli fare equally well with self-expandable as well as ballon-expandable valves, and even have less valve dysfunction at 12 months, similar outcomes are to be expected. A small aortic annulus was encountered in almost 75 % of women enrolled in the RHEIA trial, and the hemodynamic results at 30 days and 1 year are reassuring.

Furthermore, patients with bicuspid aortic valves were excluded from the trial and the reported follow-up results are up to one year, consequently the long-term results are awaited as well as future trials which will include women with severely stenotic bicuspid aortic valves.

Related publications

• Contemporary guideline-directed management of patients with severe aortic valve stenosis
• Transcatheter aortic valve implantation versus surgical aortic valve replacement in patients at low to intermediate surgical risk: rationale and design of the randomised DEDICATE Trial

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