Bicuspid aortic valve (BAV) disease is the most common congenital heart condition, with an approximate prevalence of 1% in recent studies. The bicuspid aortic valve is composed of two uneven leaflets, typically presenting a central raphe that connects the fused leaflets, leading to various morphotypes. This anatomical alteration increases hemodynamic stress, resulting in early degeneration of the valve and a higher risk of valve dysfunction, manifesting as either stenosis or aortic insufficiency. Additionally, patients frequently present with associated aortopathy, requiring surgical intervention in approximately 30% of cases.

In the era of transcatheter aortic valve implantation (TAVI), several randomized studies support the procedure’s use in increasingly younger, lower-risk patients. However, for patients with BAV, TAVI remains an off-label indication due to the limited number of comparative studies in the literature assessing TAVI versus AVR in these patients, as they were excluded from major clinical trials. This study aims to evaluate the association between treatment strategy and outcomes, including hospital mortality, complications, and resource use in BAV patients.

A retrospective analysis was conducted on a multicenter cohort of 56,331 patients with severe aortic stenosis and BAV who underwent AVR (93.2%) or TAVI (6.8%) between 2012 and 2019. Over the study period, there was a gradual increase in the use of the percutaneous approach. Females constituted 31.4% of the cohort, with a higher proportion in the TAVI group (38.8% vs. 30.8%, p < 0.001). Consistent with other series, TAVI patients were significantly older than those in the AVR group (69 vs. 59 years, p < 0.001) and had a higher prevalence of comorbidities (heart failure, pulmonary, liver, or renal disease). The primary outcome assessed was in-hospital mortality during the initial stay, and secondary outcomes included periprocedural complications, such as cardiac arrest and myocardial infarction (MI), need for pacemaker implantation (PM), respiratory infection (pneumonia), hemorrhagic complications, acute kidney injury, readmission (at 30 and 90 days post-intervention), and costs. Results showed higher mortality in the TAVI group compared to the AVR group (1.6 vs. 0.8, p < 0.001), though these differences were resolved after risk adjustment. Periprocedural complications analysis revealed fewer hemorrhagic complications, acute renal failure, and respiratory infections in TAVI patients compared to AVR. However, the TAVI group had a higher PM implantation rate (7.6 vs. 4.4, p< 0.001), though this rate was lower than that observed in previous TAVI studies with tricuspid valves (around 17%). Furthermore, the TAVI group showed a higher 90-day readmission rate, mainly for cardiovascular reasons (non-significant, as with mortality when risk-adjusted), and a greater risk of reintervention (defined as angiography, valvuloplasty, or TAVI in subsequent hospitalizations) with an OR of 3.9, resulting in higher hospital costs despite a shorter initial stay (average of 3.1 days).

COMMENTARY:

Currently, TAVI is recognized as the procedure of choice in older patients (> 75 years) or those with high surgical risk for severe aortic stenosis. For intermediate-risk patients, the optimal treatment is determined individually by the Heart Team, considering the patient’s clinical, anatomical, and functional characteristics. However, current clinical practice guidelines do not include recommendations for patients with severe aortic stenosis secondary to BAV.

While several studies have demonstrated TAVI’s non-inferiority compared to conventional surgery in the previously mentioned groups, few comparative studies are available for patients with BAV. This study by Sanaiha et al. provides one of the largest series to date, allowing a representative number of both procedures in patients with this valvulopathy and concomitant severe aortic stenosis. However, it is important to remember that this is a non-randomized cohort study with population groups showing different baseline characteristics (evidenced by differences in mortality and readmission rates adjusted after applying risk-adjusted statistical techniques). Regarding complications, it is unsurprising that the surgical group had a higher hemorrhagic risk due to the more invasive nature of open surgery, where platelet dysfunction and coagulation factor deficiency after extracorporeal circulation are usually the norm. Additionally, the surgical group had a higher rate of respiratory infection, likely related to prolonged mechanical ventilation time, and an increased risk of renal impairment. On the other hand, the association between TAVI and a higher postoperative PM risk is well established, even in this patient subgroup. Regarding valve function, information on anatomical (valve ring size, prosthetic size) and functional aspects (short- and mid-term valve gradients or paravalvular leakage) post-procedure is lacking, which is particularly relevant in patients with presumably longer life expectancy, where valve durability is critical. Furthermore, this study did not include patients with BAV and associated aortopathy (root/aorta dilation), a common clinical finding that could increase procedural risk in TAVI or impact follow-up outcomes as it remains an untreated concomitant condition.

From an economic perspective, TAVI implantation in BAV does not appear to reduce healthcare costs, given TAVI’s inherent need for specific perioperative studies (such as aortic computed tomography), the higher cost of prostheses, and the increased risk of subsequent procedures.

In conclusion, despite being one of the largest series analyzing BAV patients undergoing open surgery versus TAVI without mortality differences and with fewer periprocedural complications with TAVI, it is crucial to highlight the need for randomized and long-term studies to better define TAVI’s implications for younger BAV patients. Such studies would provide stronger conclusions on the efficacy and safety of this technique in this patient subgroup.

REFERENCE:

Sanaiha Y, Hadaya JE, Tran Z, Shemin RJ, Benharash P. Transcatheter and surgical aortic valve replacement in patients with bicuspid aortic valve stenosis. Ann Thorac Surg. 2023 Mar;115(3):611-618. doi: 10.1016/j.athoracsur.2022.06.030.