PARTNER A: Difference between revisions

In patients with symptomatic severe AS who are high-risk surgical candidates (expected periprocedural mortality ~ 15%), is transcatheter aortic-valve replacement (TAVR) noninferior to surgical AVR with regard to all-cause mortality?

In patients with symptomatic severe AS who are high-risk surgical candidates (expected periprocedural mortality ~ 15%), TAVR was associated with similar all-cause mortality to surgical AVR at 1 year.

It is well-accepted that aortic valve replacement prolongs survival in patients with severe aortic stenosis (AS).<ref>[http://www.ncbi.nlm.nih.gov/pubmed/7127696 Schwarz F, et al. "The effect of aortic valve replacement on survival." ''Circulation.'' 1982;66(5):1105-1110.]</ref> However, the condition often presents at an advanced age when patients are poor surgical candidates due to multiple comorbidities. Transcatheter aortic valve replacement (TAVR) is an emerging technology whereby a self-expanding aortic valve prosthesis is inserted using a transcatheter approach. The [[PARTNER B]] trial established the role of TAVR in patients with severe AS who are not surgical candidates due to cormorbidity, as TAVR led to an absolute 20% reduction in all-cause mortality at 1 year with TAVR versus medical therapy. Given its inherently less invasive design, the benefit of TAVR may extend to patients who remain surgical candidates but are nevertheless at high risk for periprocedural complications.

The 2011 Placement of Aortic Transcatheter Valves, cohort A (PARTNER A) trial randomized 699 patients with symptomatic severe AS at high perioperative risk (estimated perioperative mortality ~ 15%) to TAVR or surgical AVR. At 1 year, the primary endpoint of all-cause mortality was 2% lower in the TAVR group, meeting prespecified criteria for noninferiority (superiority not established). However, TAVR was associated with a borderline statistically significant (p=0.07) 3% absolute increase in major stroke at 1 year as well as a 15% increase in vascular complications. A composite outcome of all-cause mortality or major stroke showed very similar outcomes with TAVR and surgical AVR. In addition, patients in both groups had similar improvements in 6-minute walk distance and NYHA class at 1 year. Importantly, comparative outcomes with TAVR vs. surgical AVR stratified by access approach (transfemoral vs. transapical) were similar, although the transapical subgroup was underpowered. Complications more prevalent with open AVR included a 10% higher rate of major bleeding and a borderline statistically significant (p=0.07) 5% higher rate of new atrial fibrillation. Patients who received TAVR had an ICU length of stay that was 2 days shorter and an overall hospitalization that was 4 days shorter.

Based largely on the results of PARTNER A, TAVR is now generally accepted as an appropriate alternative to surgical AVR in patients at high risk for operative complications. Notably, the 5 year results of PARTNER A were published in 2015 and continue to show no difference in mortality with TAVR versus open AVR, although there was a 10% increase in prevalence of severe aortic regurgitation, a complication for which careful monitoring is required in all TAVR patients and reintervention may be required.<ref name="partner fu">{{#pmid:25788234}}</ref>

* TAVR if indication for AVR but "prohibitive risk" for surgical AVR and predicted post-TAVR survival >12 months (class I, level B)

* TAVR if indication for AVR but high surgical risk for surgical AVR (class IIa, level B)

* Percutaneous aortic balloon dilation as bridge to surgical AVR or TAVR (class IIb, level C)

** TAVR (n=348)

* Surgical candidate for open AVR

''From the TAVR group.''

* At enrollment, patients underwent mapping to determine candidacy for transfemoral vs. transapical TAVR approach

** '''TAVR''' - Esophageal echocardiographically-guided, percutaneous placement of a trileaflet bovine valve with stainless steel support frame deployed by balloon during rapid RV pacing

''Presented as TAVR vs. surgical AVR.''

* Excluded specific groups that may benefit from TAVR, including those with CAD, severe PVD, and LVEF <20%<ref>[http://www.ncbi.nlm.nih.gov/pubmed/21251642 George JC et al. "Transcatheter aortic valve implantation: Lessons from the PARTNER (Placement of Aortic Transcatheter Valves) trial." ''JACC Cardiovascular Interventions.'' 2011;4(1):132-133.]</ref>

* Significant (4.6%) crossover to surgical AVR in the TAVR group, which may have biased toward noninferiority of TAVR

* Actual surgical mortality at 30 days was 3% lower than expected by STS score, potentially limiting power to detect superiority of TAVR over surgical AVR