Transcatheter Aortic Valve Replacement Is an Effective Alternative to Surgical Replacement

Data from the PARTNER cohort A trial show transcatheter aortic valve replacement produces similar mortality rates at one year compared with the standard procedure.

Vinod Thourani, MD, Emory University School of Medicine, presented results from the PARTNER cohort A trial at ACC.13, the 62nd Annual Scientific Session & Expo of the American College of Cardiology. This three-year parallel study compared outcomes from transfemoral or transapical transcatheter aortic valve replacement (TAVR) vs. surgical aortic valve replacement (AVR) in high-risk patients with severe arterial stenosis (AS).

In all, 699 patients were randomized; those with adequate femoral/iliac vessel diameter (492) were randomized to either transfemoral TAVR (244) or surgical AVR (248); and those with inadequate diameter (207) to either transapical TAVR (104) or surgical AVR (103).

About 75% of participants had coronary artery disease, 28% had cerebrovascular disease, 43% underwent prior coronary artery bypass grafting, 42% had peripheral vascular disease, and 43% had chronic obstructive pulmonary disease. Average age of participants was nearly 84 years, with women making up 43% of the cohort.

Primary endpoint was all-cause mortality at one year. Secondary safety endpoints included major stroke, transient ischemic attack (TIA), vascular complications, rehospitalization, new pacemakers, and surgical complications such as bleeding and infection. Secondary efficacy endpoints included bioprosthetic valve regurgitation (especially paravalvular), mitral regurgitation (MR), and structural valve deterioration.

Exclusion criteria included: noncalcified aortic valve, disease precluding safe sheath insertion, untreated coronary artery disease requiring revascularization, severe AR or MR or prosthetic valve, acute MI within a month, upper gastrointestinal bleeding within three months, cerebrovascular accident or TIA within six months, most other cardiac procedures within one month or within six months for drug-eluting stent, and hemodynamic instability.

Vascular complications and all strokes were higher with TAVR (18.0%) vs. AVR (4.8%) at one year (P< 0.001). The need for new permanent pacemakers was similar at one year for the TAVR and AVR groups (5.7% vs. 5.0%, P=0.68). At one year, TAVR demonstrated noninferiority to AVR for all-cause mortality (24.2% vs. 26.8%), with transfemoral TAVR also individually demonstrating noninferiority compared with AVR (22.2% vs. 26.4%). There was one procedural death with AVR, and three with TAVR. Major bleeding at one year (14.7% vs. 25.7%, P< 0.001) was lower with TAVR. Moderate to severe paravalvular AR was greater with TAVR at all time points (P< 0.05).

At two years, all-cause mortality (33.9% vs. 35.0%, P=0.31) was similar between TAVR and surgical AVR. Mortality rates improved with transfemoral TAVR compared with surgical AVR (30.9% vs. 34.6%, P=0.38), and worsened with transapical TAVR compared with surgical AVR (41.1% vs. 35.8%, P=0.44). Other outcomes including cardiovascular mortality (20.5% vs. 21.4%, P=0.48), mortality or repeat hospitalization (46.6% vs. 46.5%, P=0.84), and strokes (7.7% vs. 4.9%, P=0.52) were also similar.

Paravalvular AR was still significantly higher with TAVR (6.9% vs. 0.9%, P< 0.001), and remained unchanged in 46.2% of patients, improved in 31.5%, and worsened in 22.4%.

At three years, all-cause mortality (44.2% vs. 44.8%, P= 0.48) remained similar between TAVR and surgical AVR. Mortality with TAVR was higher in patients with comorbidities such as chronic kidney or liver disease, and atrial fibrillation. Strokes (8.2% vs. 9.3%, P= 0.76) were similar, but in surgical AVR, were higher after the second year (1 vs. 9). Moderate to severe paravalvular AR was still significantly higher in TAVR, and even mild regurgitation was a significant predictor of long-term mortality.

Overall, results highlight the emerging importance of TAVR in managing high surgical risk AS patients. Although no difference in long-term mortality was noted at three years, longer-term follow-up is necessary.

Future studies will also need to assess the relative utility of transfemoral versus transapical TAVR. Longer-term outcomes for TAVR remain unknown and are necessary to assess valve performance and analyze late complications before TAVR can be widely applied. Future efforts must address TAVR procedural complications, including strokes, vascular events, and paravalvular regurgitation.