Clinical outcomes and prognostic factors of transcatheter aortic valve implantation in bicuspid aortic valve patients

Bicuspid Aortic Valve Disease: Classifications, Treatments, and Emerging Transcatheter Paradigms

Bicuspid aortic valve (BAV) is a common congenital valvular malformation, which may lead to early aortic valve disease and bicuspid-associated aortopathy. A novel BAV classification system was recently proposed to coincide with transcatheter aortic valve replacement being increasingly considered in younger patients with symptomatic BAV, with good clinical results, yet without randomized trial evidence. Procedural technique, along with clinical outcomes, have considerably improved in BAV patients compared with tricuspid aortic stenosis patients undergoing transcatheter aortic valve replacement. The present review summarizes the novel BAV classification systems and examines contemporary surgical and transcatheter approaches.

Bicuspid Valve Sizing for Transcatheter Aortic Valve Implantation: The Missing Link

Transcatheter aortic valve implantation (TAVI) is a well-recognized and established therapy for severe aortic stenosis, with expanding indications toward younger patients with low surgical risk profile. As bicuspid aortic valve (BAV) affects ~1-2% of the population, it may be speculated that an increasing number of patients with degenerated BAV may eventually need TAVI during the course of the disease. On the other hand, BAV represents a challenge due to its peculiar anatomical features and the lack of consensus on the optimal sizing strategy. The aim of this paper is to review the peculiar aspects of BAV and to discuss and compare the currently available sizing methods. Special attention is given to the role of pre-procedural imaging, mostly with multislice computed tomography, and to the aspects that operators should evaluate in order to ensure an optimal procedural planning and avoid procedural-related complications.

Aortic annulus sizing in bicuspid and tricuspid aortic valves using CT in patients with surgical aortic valve replacement

The purpose of this study was to evaluate whether bicuspid anatomy affects the discrepancy between CT-derived annular size and intraoperative size. We retrospectively analyzed annular measurements in 667 patients who underwent surgical aortic valve replacement (AVR). Preoperative CT measurements of the aortic annulus were compared to surgically implanted valve sizes. To evaluate whether the bicuspid valve affects the differences between CT annulus diameter and surgical AVR size, patients with diameter larger by > 10% (CT-Lg group) on CT, compared to surgical AVR size, were compared with those having size difference < 10% (CT-Sim group). Propensity score matching yielded 183 matched patients from each group. Bicuspid aortic valve annulus parameters significantly correlated with surgical aortic valve size (r = 0.52-0.71; for all, p < 0.01). The most representative measurements corresponded to surgical aortic valve size were area-derived diameters in tricuspid aortic valve (r = 0.69, p < 0.001) and bicuspid without raphe (r = 0.71, p < 0.001), and perimeter-derived diameter in bicuspid with raphe (r = 0.63, p < 0.001). After propensity score matching, native valve type was not different between CT-Sim and CT-Lg groups. In multivariable analysis, the difference between CT-derived diameter and surgical AVR size was affected by the operator factor and types of prosthesis. Bicuspid aortic annulus diameters measured on CT showed a significant correlation with surgical aortic valve size. The difference between CT-derived diameter and surgical AVR size is affected by operator factor and the types of prosthesis but not affected by the bicuspid valve.

Increased Rate of New-onset Left Bundle Branch Block in Patients With Bicuspid Aortic Stenosis Undergoing Transcatheter Aortic Valve Implantation (From a National Registry)

There is a growing interest in transcutaneous aortic valve implantation (TAVI) therapy among patients with bicuspid severe aortic stenosis (BAV). Conduction disturbances remain a frequent complication of TAVI, and new-onset permanent LBBB (NOP-LBBB) post-TAVI may be a marker of worse outcomes. We aimed to evaluate the rate of NOP-LBBB following TAVI among patients with BAV as compared to tricuspid severe aortic stenosis (TAV). Patients enrolled in the multicenter (5 centers) Bicuspid AS TAVI Registry were reviewed and compared with patients with TAV. Patients with previous aortic valve replacement, other valve morphologies and those with preprocedural LBBB or pacemaker were excluded. NOP-LBBB was defined as LBBB first detected and persisting 30-days following TAVI. A total of 387 patients (66 with BAV, 321 with TAV), age 80.3 ± 7.3, 47% females were analyzed. The device success rates were 95% in both groups without any conversions to surgery. The rate of NOP-LBBB was significantly higher among patients with BAV versus TAV (29.2% vs 16.9%, p = 0.02). However, the rate of post procedural pacemaker implantation was similar (14.8% vs 12.5%; respectively, p = 0.62). In BAV and TAV groups, 1-year mortality (6.1% vs 7.2%; respectively, p = 0.75) and stroke rates (6.1% vs 3.5%; respectively, p = 0.30) were not significantly different. Multivariate analysis identified BAV as an independent predictor of NOP-LBBB (AdjOR = 2.7, 95%CI 1.3 to 5.4). Furthermore, BAV subtypes with raphe (type 1) were identified as independent predictors of NOP-LBBB (AdjOR = 3.2, 95%CI: 1.5 to 6.7). In conclusion, patients with BAV undergoing TAVI have greater risk for developing NOP-LBBB compared with patients with TAV and the presence of raphe was associated with increased risk of NOP-LBBB. The prognostic significance for this finding warrants further evaluation in future studies.

Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Stenosis

After 15 years of successive randomized, controlled trials, indications for transcatheter aortic valve replacement (TAVR) are rapidly expanding. In the coming years, this procedure could become the first line treatment for patients with a symptomatic severe aortic stenosis and a tricuspid aortic valve anatomy. However, randomized, controlled trials have excluded bicuspid aortic valve (BAV), which is the most frequent congenital heart disease occurring in 1% to 2% of the total population and representing at least 25% of patients 80 years of age or older referred for aortic valve replacement. The use of a less invasive transcatheter therapy in this elderly population became rapidly attractive, and approximately 10% of patients currently undergoing TAVR have a BAV. The U.S. Food and Drug Administration and the "European Conformity" have approved TAVR for low-risk patients regardless of the aortic valve anatomy whereas international guidelines recommend surgical replacement in BAV populations. Given this progressive expansion of TAVR toward younger and lower-risk patients, heart teams are encountering BAV patients more frequently, while the ability of this therapy to treat such a challenging anatomy remains uncertain. This review will address the singularity of BAV anatomy and associated technical challenges for the TAVR procedure. We will examine and summarize available clinical evidence and highlight critical knowledge gaps regarding TAVR utilization in BAV patients. We will provide a comprehensive overview of the role of computed tomography scans in the diagnosis, and classification of BAV and TAVR procedure planning. Overall, we will offer an integrated framework for understanding the current role of TAVR in the treatment of bicuspid aortic stenosis and for guiding physicians in clinical decision-making.

Minimally-invasive versus transcatheter aortic valve implantation: systematic review with meta-analysis of propensity-matched studies

Background

Minimally invasive aortic valve replacement (MiAVR) and transcatheter aortic valve implantation (TAVI) provide aortic valve replacement (AVR) by less invasive methods than conventional surgical AVR, by avoiding complete sternotomy. This study directly compares and analyses the available evidence for early outcomes between these two AVR methods.

Methods

Electronic databases were searched from inception until August 2019 for studies comparing MiAVR to TAVI, according to predefined search criteria. Propensity-matched studies with sufficient data were included in a meta-analysis.

Results

Eight studies with 9,744 patients were included in the quantitative analysis. Analysis of risk-matched patients showed no difference in early mortality (RR 0.76, 95% CI, 0.37–1.54, P=0.44). MiAVR had a signal towards lower rate of postoperative stroke, although this did not reach statistical significance (OR 0.42, 95% CI, 0.13–1.29, P=0.13). MiAVR had significantly lower rates of new pacemaker (PPM) requirement (OR 0.29, 95% CI, 0.16–0.52, P<0.0001) and postoperative aortic insufficiency (AI) or paravalvular leak (PVL) (OR 0.05, 95% CI, 0.01–0.20, P<0.0001) compared to TAVI, (OR 0.42, 95% CI, 0.13–1.29, P=0.13), while acute kidney injury (AKI) was higher in MiAVR compared to TAVI (11.1% vs. 5.2%, OR 2.28, 95% CI, 1.25–4.16, P=0.007).

Conclusions

In patients of equivalent surgical risk scores, MiAVR may be performed with lower rates of postoperative PPM requirement and AI/PVL, higher rates of AKI and no statistical difference in postoperative stroke or short-term mortality, compared to TAVI. Further prospective trials are needed to validate these results.

Transcatheter Aortic Valve Replacement of a Bicuspid Aortic Valve in a Heart Transplant Recipient

Patients with heart transplants who present with severe aortic stenosis may be deemed high-risk surgical candidates due to immunosuppression and multiple comorbid conditions. Appropriately selected patients may be successfully treated with transcatheter aortic valve replacement. (Level of Difficulty: Advanced.)

Outcomes of Transcatheter Aortic Valve Replacement in Patients With Bicuspid Aortic Valve Disease

Background:

Patients with bicuspid aortic valve (AV) stenosis were excluded from the pivotal evaluations of transcatheter AV replacement (TAVR) devices. We sought to evaluate the outcomes of TAVR in patients with bicuspid AV stenosis in comparison with those with tricuspid AV stenosis.

Methods:

We used data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry (November 2011 through November 2018) to determine device success, procedural outcomes, post-TAVR valve performance, and in-hospital clinical outcomes (mortality, stroke, and major bleeding) according to valve morphology (bicuspid versus tricuspid). Results were stratified by older and current (Sapien 3 and Evolut R) generation valve prostheses. Medicare administrative claims were used to evaluate mortality and stroke to 1 year among eligible individuals (≥65 years).

Results:

After exclusions, there were 170 959 eligible procedures at 593 sites during the specified interval. Of these, 5412 TAVR procedures (3.2%) were performed in patients with bicuspid AV, including 3705 with current-generation devices. In comparison with patients with tricuspid valves, patients with bicuspid AV were younger and had a lower Society of Thoracic Surgeons Predicted Risk of Operative Mortality score. When current-generation devices were used to treat patients with bicuspid AV, device success increased (93.5 versus 96.3; P =0.001) and the incidence of 2+ aortic insufficiency declined (14.0% versus 2.7%; P <0.001) in comparison with older-generation devices. With current-generation devices, device success was slightly lower in the bicuspid (versus tricuspid) AV group (96.3% in bicuspid versus 97.4% in tricuspid, P =0.07), with a slightly higher incidence of residual moderate or severe aortic insufficiency among patients with bicuspid AV (2.7% versus 2.1%; P <0.001). A lower 1-year adjusted risk of mortality (hazard ratio, 0.88 [95% CI, 0.78–0.99]) was observed for patients with bicuspid AV versus patients with tricuspid AV in the Medicare-linked cohort, whereas no difference was observed in the 1-year adjusted risk of stroke (hazard ratio, 1.14 [95% CI, 0.94–1.39]).

Conclusions:

Using current-generation devices, procedural, postprocedural, and 1-year outcomes were comparable following TAVR for bicuspid AV versus tricuspid AV disease. With newer-generation devices, TAVR is a viable treatment option for patients with bicuspid AV disease.

Transcatheter aortic valve replacement in low risk patients

Transcatheter aortic valve replacement (TAVR) is a relatively new technology that has grown exponentially over the past decade. Although it was initially restricted to elderly patients at very high or prohibitive surgical risk, it is currently being evaluated as a treatment option in younger and lower risk patients. The increasing experience of the Heart Teams, along with the continued refinement of transcatheter valve technology has resulted in TAVR achieving results comparable to those of surgery for treating intermediate-risk patients. Furthermore, promising preliminary results have been obtained from observational and propensity matched studies in low risk patients, and a small randomized trial showed the non-inferiority of TAVR vs. SAVR regarding early and late (up to 6 years) outcomes. Three ongoing randomized trials will provide the definite response about the safety and efficacy of TAVR for treating low risk patients with severe aortic stenosis in the near future. The (expected) positive results of these studies would establish the basis for TAVR as the preferred treatment for the majority of patients with aortic stenosis. However, continuous research efforts for better determining valve durability among TAVR recipients, as well as reducing some of the genuine and frequent complications of TAVR (e.g. conduction disturbances) are important in this final effort for making TAVR the default treatment for aortic stenosis.

Recent updates in transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) has evolved from a challenging intervention to a standardized, simple, and streamlined procedure with over 350,000 procedures performed in over 70 countries. It is now a novel alternative to surgical aortic valve replacement in patients with intermediate surgical risk and its indications have been expanded to cohorts with bicuspid aortic valves, low surgical risk, and younger age and fewer comorbidities. Attention should be paid to further reducing remaining complications, such as paravalvular aortic regurgitation, conduction abnormalities, cardiac tamponade, and stroke. The aim of this review is to provide an overview on the rapidly changing field of TAVI treatment and to explore past achievements, current issues, and future perspectives of this treatment modality.