Phoenix – Since 2019, when transcatheter aortic valve replacement (TAVR) received FDA approval in the U.S. for low surgical risk aortic stenosis patients, the field of structural heart disease treatment has been dramatically changed. TAVR, too, continues to evolve, bringing new complexities around imaging, access, anatomical considerations, and a full range of issues regarding lifetime management of the aortic valve stenosis patient, all of which were under discussion as TVT 2023 began on June 7th in Phoenix, Arizona.

An opening session on structural heart disease imaging reviewed anatomy, guidance, and technical outcomes. Vratika Agarwal, MD, Assistant Professor of Medicine at Columbia University Medical Center in New York, presented on TAVR in bicuspid aortic valves, performing a risk assessment for the performance of the BASILICA procedure in valve-in-valve procedures. The use of TAVR for the treatment of aortic regurgitation (which is undergoing investigation) was also discussed.

Bicuspid aortic valves are more common in men and affect up to 2% of all adults. In this patient population, isolated aortic disease including aortic stenosis and/or aortic regurgitation and aortic aneurysm have been reported. Dr. Agarwal described data from the Society for Thoracic Surgeons/American College of Cardiology (STS/ACC) Registry showing that after placement of newer generation valves, paravalvular leak in bicuspid valves does not differ from tri-leaflet valves, and that 30-day and 1-year mortality rates do not differ, but bicuspid aortic valve patients do see a higher risk of stroke at 30 days. A recent meta-analysis of TAVR versus surgical aortic valve replacement in bicuspid valve patients demonstrated no difference in all-cause mortality at 21 to 24 months, with TAVR showing a higher rate of permanent pacemaker implantation and a lower rate of acute kidney injury and transfusion. Dr. Agarwal also shared a case that emphasized the procedural importance of imaging in the treatment of bicuspid aortic valve patients, using 3D transesophageal echocardiography (TEE) and computed tomography (CT) for aortic regurgitation evaluation, TAVR valve positioning and deployment, evaluation of paravalvular leak, calcium displacement, and an assessment of the ascending aorta.

The next presentation by Dr. Agarwal focused on mitigating risks around coronary obstruction in valve-in-valve TAVR, which is associated with a higher risk of stroke or coronary obstruction due to the risk of debris that may be dislodged during the procedure. The risk for coronary artery obstruction is higher in women and obstruction occurs more frequently in bioprosthetic surgical valves. Performing a valve-in-valve TAVR procedure with BASILICA can help prevent coronary artery obstruction, which has been reported at 0.7% but with 41% rate of mortality at 30 days. BASILICA stands for bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction during TAVR. Dr. Agarwal also discussed the snorkeling technique as a method of prevention, but noted its accompanying risks, including extrinsic compression, deformation, and thrombosis, possibly causing delayed coronary thrombotic occlusion.

The treatment of native aortic valve regurgitation with a TAVR procedure is also under discussion at TVT. Dr. Agarwal described acute and chronic aortic regurgitation in detail. Acute aortic regurgitation may result from an abnormality of the aorta or aortic valve leaflets (possibly due to endocarditis), an iatrogenic injury (arising after transcatheter procedures), or blunt chest trauma. Chronic aortic regurgitation can arise from the presence of bicuspid aortic valves, aortic disease, rheumatic disease, or calcific aortic disease. Dr. Agarwal described how “TAVR for isolated, chronic aortic regurgitation is challenging, because of dilation of the aortic annulus and aortic root,” noting also that “there is a lack of adequate leaflet calcification for anchoring.” Risks from TAVR to treat aortic regurgitation include valve migration and paravalvular leak. Two recent large database studies (Medicare and National [Nationwide] Inpatient Sample [NIS]) compared TAVR and surgical aortic valve replacement for native aortic valve regurgitation. The studies showed similar 30-day mortality between the two procedures, and the NIS database study showed TAVR with more favorable hospital outcomes including for acute kidney injury and cardiogenic shock. The Medicare database study demonstrated an increased risk of mortality, redo aortic valve replacement, stroke, and endocarditis for TAVR patients at 31 months. Dr. Agarwal concluded with the case of a 65-year-old male with severe aortic regurgitation who received a JenaValve (currently investigational use only), with the use of 3D echo and CT assessment and guidance.

TVT’s TAVR Spotlight session on Practical Tips & Tricks for Success included a presentation by Joe Walsh MD, MSc, Director, Structural Heart, at St. Alphonsus Health System in Boise, Idaho, on minimalist TAVR in 2023. Dr. Walsh shared important “microsteps” for the TAVR procedure focusing on sedation and the hemodynamic monitoring strategy, pigtail access, large-bore access and pre closure, crossing the aortic arch, the left ventricular pacing run and valve deployment, and the use of protamine and access closure. A minimalist TAVR procedure at St. Alphonsus Health System uses minimal sedation, with recommended lidocaine at 20 cc under ultrasound. In addition, sheath or, preferably, radial access is used instead of an arterial line, and 2 peripheral IV lines instead of a central line. For large-bore access, Dr. Walsh recommended the use of ultrasound, noting the importance of visualizing the needle entering the common femoral. Pre closure can be done with a Perclose (Abbott Vascular) “90% of the time,” he said. To cross the arch, Dr. Walsh described a “kite string” technique with a 2 cc soft balloon inflation. Instead of a temporary pacemaker, he recommended LV pacing as “faster, safer, and cheaper.” When deploying the valve, a high deployment overlapping the cusp can precisely align the valve with the annulus, and Dr. Walsh shared a study demonstrating that this approach can lead to lower conduction abnormalities and reduced permanent pacemaker implantation. He also described data behind the use of protamine for a significant reduction in bleeding complications and mortality for TAVR patients. Currently, 2 operators at St. Alphonsus Health System use this minimalist approach, and 158 transfemoral TAVR procedures performed in 2022 experienced zero mortality, major vascular complications, stroke, or major/minor bleed, with permanent pacemaker implantation in 5%.

In the same session focusing on tips for success, Tamim Nazif, MD, New York-Presbyterian Hospital and Columbia University Irving Medical Center in New York, discussed stroke in TAVR and when to use cerebral embolic protection devices. According to a multicenter cohort (n=1061), a stroke is of a higher concern in TAVR as compared with surgical aortic valve replacement, with the majority of strokes ischemic, classified as major, and occurring within 24 to 48 hours post procedure. A study by the STS/ACC TVT Registry (n=101,430) showed similar results and noted greater than 50% of strokes resulted in substantial impairment of social and recreational activities. Thirty-day mortality for stroke versus non-stroke patients post TAVR was reported by the STS/ACC TVT Registry as 16.7% versus 3.7%, respectively. More than 70% of patients have been shown to have cerebral lesions following TAVR, as assessed by diffusion-weighted magnetic resonance imaging. Available cerebral embolic protection devices include the Sentinel (Boston Scientific), FDA approved as of 2017, with others on the horizon currently in clinical trials. The SENTINEL IDE study showed debris capture in greater than 99% of patients and a 63% reduction in stroke at ≤72 hours post procedure with use of the Sentinel device. Another trial, PROTECTED TAVR, sought to further clarify the effect of cerebral embolic protection, with a neurological exam in all patients post procedure, and a primary endpoint of all stroke at 72 hours or discharge. However, some of the limitations of the trial, including limited heterogeneity across subgroups, failed to clarify the use of cerebral embolic protection in TAVR. PROTECTED TAVR did demonstrate lower stroke rates than expected, but there was concern for selection bias given the commercial availability of the Sentinel device. An ongoing multicenter trial, the British Heart Foundation (BHF) PROTECT-TAVI trial, has, to date, enrolled 7730 patients with a 1:1 randomization comparing TAVR with Sentinel versus TAVR alone. The possibility of predicting periprocedural stroke has been under evaluation as well, through studies from the STS/ACC TVT Registry and the TASK study. In addition, a single-center study of 433 patients aims to evaluate CT aortic valve calcium score as a possible predictor of stroke. Dr. Nazif concluded by offering clinicians some guidance around the use of cerebral embolic protection, beginning with an emphasis on safety first (a learning curve of 20 [recommended straightforward] cases as was seen in PROTECTED TAVR). He notes that finances can be a consideration. Operators should categorize their use of cerebral embolic protection devices – do they want to use them routinely, be selective, or not at all? If selective use is chosen, risk prediction models as well as anatomical risk factors should be incorporated, while understanding their limitations. The hope is that cerebral embolic protection device use in TAVR will be further clarified after evidence and results from BHF PROTECT-TAVI and the several cerebral embolic protection devices currently in trials become available.

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TVT Newsroom (With a Special Focus on TAVR)