The Role of Transcatheter Aortic Valve Replacement in Asymptomatic Aortic Stenosis: A Feasibility Analysis

Abstract

Surgical aortic valve replacement (SAVR) is the current treatment of choice for good surgical candidates with moderate to severe symptomatic aortic stenosis (AS). As transcatheter aortic valvular replacement (TAVR) has shown an improved one and two-year all-cause mortality, it has been chosen for moderately symptomatic severe AS patients. The purpose of this review was to perform a clinical comparison of TAVR vs. SAVR and to analyze the Health Index Factor (HIF) that makes TAVR a treatment of choice in asymptomatic AS patients.An extensive literature search of PubMed, Cochrane, and Embase databases was performed using the keywords "Aortic stenosis", "SAVR", "TAVR", and "Asymptomatic". A total of 45 prospective randomized clinical trials in the English language that were published from the year 2000 onwards were included in the final analysis. It has been found that 59.3% of asymptomatic AS patients are likely to die in the next five years without proactive treatment. Multiple studies have proven that early intervention with aortic valve replacement is superior to conservative treatment in severe asymptomatic AS; however, the choice between SAVR and TAVR is not well established. The NOTION Trial, SURTAVI Trail, and PARTNER 3 study have shown the non-inferiority of TAVR over SAVR, during one-year follow-up for low surgical risk patients. Evolut Low-Risk study and Early TAVR are the only two prospective studies performed to date that have enrolled patients with asymptomatic severe AS. The Evolut Trial demonstrated no difference in all-cause mortality at 30 days (1.3% vs. 4.8%. p=0.23), and 12 days (1.3% vs. 6.5%, p=0.11). Additionally, TAVR also decreases the risk of post-procedural atrial fibrillation, acute kidney injury (AKI), and rehospitalization, and leads to significant improvement in the mean trans-aortic pressure gradient. TAVR also showed marked improvement in the 30-day Quality of Life (QOL) index, where SAVR did not report any significant change in the QOL index. However, the official recommendations of Early TAVR are still awaited. TAVR has consistently shown a statistically non-significant difference in case mortality, risk of stroke, and rehospitalization with moderate to high surgical risk patients whereby recent initial trials have shown significant improvement in the QOL index and hemodynamic index for patients with asymptomatic disease. More extensive studies are required to prove the risk stratifications, long-term outcomes, and clinical characteristics that would make TAVR a preferred intervention in asymptomatic patients.

Natural history and clinical burden of moderate aortic stenosis: a systematic review and explorative meta-analysis

“…We also postulate that in some cases, especially those with low-flow low-gradient aortic stenosis due to impaired LVEF, a truly severe aortic stenosis might be erroneously downgraded to mAS and treated conservatively, despite a clear indication for intervention. The idea of aortic stenosis as a spectrum of hazard that ranges from mAS to asymptomatic severe aortic stenosis to symptomatic severe aortic stenosis is being tested also in ongoing randomized and controlled clinical trials such as the EARLY-TAVR trial, which is evaluating the TAVI on patients with asymptomatic severe aortic stenosis, 32 and the TAVR UNLOAD trial, which is testing TAVI on patients with mAS and heart failure with reduced LVEF. 8 Our results corroborate this hypothesis and highlight that we should not neglect mAS and at least screen it for severity and symptoms.…”