Diagnosis and Outcomes of Transcatheter Aortic Valve Implantation in Bicuspid Aortic Valve Stenosis

A Clinical Audit on the Indications for Intervention With Transcatheter Aortic Valve Implantation Over Surgical Aortic Valve Replacement in Aortic Stenosis Patients in Mohammed Bin Khalifa Bin Salman Al Khalifa Specialist Cardiac Centre

Introduction Transcatheter aortic valve implantation (TAVI) is a novel treatment strategy used to treat patients with symptomatic aortic stenosis. It utilizes a percutaneous approach and is preferred over surgical aortic valve replacement (SAVR) in patients at high surgical risk. The aim of this study was to audit the indications of the intervention with TAVI over SAVR in Bahrain Defence Force Hospital, Mohammed Bin Khalifa Bin Sulman AlKhalifa Cardiac Centre (BDF-MKCC), as well as note the outcomes of patients who underwent TAVI. Methods The indications for allocating aortic stenosis patients to TAVI over SAVR in BDF-MKCC were studied with regard to the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery (ESC/EACTS) guidelines published in 2017. Data from 82 patients, which accounts for all patients who underwent TAVI, were collected retrospectively from electronic medical records and the percentage of compliance was calculated and analyzed. Results The compliance percentages of the 23 parameters for the intervention with TAVI that have been set by the ESC/EACTS are calculated, where BDF-MKCC were fully adherent to 12 out of the 23 standards. Moreover, the total number of patients that are compliant with all standards is 13 out of 82 (15.85%) compliant patients. Conclusion The centre showed non-compliance to many of the published standards. Hence, we created a checklist to ensure that the international guidelines are followed. We are looking forward to re-audit this aspect in the near future, to make certain that changes were done. We would also like to do a comparative study to compare the patients' outcomes before and after implementing the 2017 ESC/EACTS guidelines. Furthermore, we call for further studies to be conducted in this field and that is to evaluate the standards themselves as well as the safety of TAVI in those who are not eligible for it according to the ESC/EACTS.

Identification of recurrent variants implicated in disease in bicuspid aortic valve patients through whole-exome sequencing

Bicuspid aortic valve (BAV) is the most common congenital heart defect in human beings, with an estimated prevalence in the general population of between 0.5 and 2%. Moreover, BAV is the most common cause of aortic stenosis in the pediatric population. Patients with BAV may have no symptoms for life, and some of them may progress to aortic stenosis. Genetic factors increase the susceptibility and development of BAV. However, the pathogenesis and BAV are still unclear, and more genetic variants are still needed for elucidating the molecular mechanism and stratification of patients. The present study carried out screening of variants implicated in disease in BAV patients. The whole-exome sequencing (WES) was performed in 20 BAV patients and identified 40 different heterozygous missense mutations in 36 genes (MIB2, FAAH, S100A1, RGS16, MAP3K19, NEB, TTN, TNS1, CAND2, CCK, KALRN, ATP10D, SLIT3, ROS1, FABP7, NUP205, IL11RA, NPR2, COL5A1, CUBN, JMJD1C, ANXA7, TRIM8, LGR4, TPCN2, APOA5, GPR84, LRP1, NCOR2, AKAP11, ESRRB, NGB, AKAP13, WWOX, KCNJ12, ARHGEF1). The mutations in these genes were identified as recurrent variants implicated in disease by in silico prediction tool analysis. Nine genes (MIB2, S100A1, TTN, CCK, NUP205, LGR4, NCOR2, ESRRB, and WWOX) among the 36 genes were identified as variants implicated in disease via unanimous agreement of in silico prediction tool analysis and sequenced in an independent cohort of 137 BAV patients to validate the results of WES. BAV patients carrying these variants demonstrated reduced left ventricular ejection fractions (LVEF) (63.8 ± 7.5% vs. 58.4 ± 5.2%, P < 0.001) and larger calcification volume [(1129.3 ± 154) mm³ vs. (1261.8 ± 123) mm³, P < 0.001]. The variants in TTN, NUP205 and NCOR2 genes are significantly associated with reduced LVEF, and the variants in S100A1, LGR4, ESRRB, and WWOX genes are significantly associated with larger calcification volume. We identified a panel of recurrent variants implicated in disease in genes related to the pathogenesis of BAV. Our data speculate that these variants are promising markers for risk stratification of BAV patients with increased susceptibility to aortic stenosis.

Outcome of transcatheter aortic valve replacement in bicuspid aortic valve stenosis with new-generation devices

OBJECTIVES

To compare device success and paravalvular leak rates of 3 new-generation transcatheter aortic valve replacement devices in patients with bicuspid aortic valve stenosis and to test their biomechanical performance in a computer-based simulation model of aortic root with increasing ellipticity.

METHODS

This retrospective multicentre study included 56 bicuspid aortic valve patients undergoing transcatheter aortic valve replacement with new-generation devices: Lotus/Lotus Edge (N = 15; 27%), Evolut-R (N = 20; 36%) and ACURATE neo (N = 21; 37%). Three virtual simulation models of aortic root with increasing index of eccentricity (0-0.25-0.5) were implemented. Stress distribution, stent-root contact area and paravalvular orifice area were computed.

RESULTS

Device success was achieved in 43/56 patients (77%) with comparable rates among Lotus (87%), Evolut-R (60%) and ACURATE neo (86%; P = 0.085). Moderate paravalvular leak rate was significantly lower in the Lotus group as compared to Evolut-R group (0% vs 30%; P = 0.027) and comparable to the ACURATE neo group (0% vs 10%; P = 0.33). By index of eccentricity = 0.5, Lotus showed a uniform and symmetric pattern of stress distribution with absent paravalvular orifice area, ACURATE neo showed a mild asymmetry with small paravalvular orifice area (1.1 mm2), whereas a severely asymmetric pattern was evident with Evolut-R, resulting in a large paravalvular orifice area (12.0 mm2).

CONCLUSIONS

Transcatheter aortic valve replacement in bicuspid aortic valve patients with new-generation devices showed comparable device success rates. Lotus showed moderate paravalvular leak rate comparable to that of ACURATE neo and significantly lower than Evolut-R. On simulation, Lotus and ACURATE neo showed optimal adaptability to elliptic anatomies as compared to Evolut-R.

Prosthesis Position after TAVI with Balloon-Expandable SAPIEN 3 in Bicuspid Aortic Valves

Background: Prior data suggest a correlation between the position of transcatheter heart valves (THV) and the occurrence of complications after transcatheter aortic valve implantation (TAVI) in patients with tricuspid aortic valves (TAV). However, data including a detailed analysis of prosthesis positioning in bicuspid aortic valves (BAV) are limited. Therefore, the purpose of this study was to investigate THV position after TAVI in BAV. Methods: We evaluated the THV position in 50 BAV and 50 TAV patients (all received the balloon-expandable Sapien 3 prosthesis) using fusion imaging of pre- and post-procedural computed tomography angiography. According to the manufacturers’ recommendations, a low implantation position was defined as >30% of the prosthesis below the annulus. Results: THV position was appropriate in the majority of the patients within both groups (90.0% for BAV vs. 96.0% for TAV, p = 0.240). In BAV, we observed a more pronounced THV waist (7.4 ± 4.5% vs. 5.8 ± 3.0%, p = 0.043) and a lower average THV expansion (91.9 ± 12.2% vs. 95.5 ± 2.7% of nominal expansion, p = 0.044). Conclusions: Accurate positioning in relation to the aortic annulus of the TAVI Sapien 3 prosthesis is possible in patients with BAV with results comparable to TAV. However, there is a more pronounced prosthesis waist and a lower average THV expansion in BAV.

Two operative cases of abdominal aortic aneurysm with isolated dissection of the abdominal aorta

Objective: Isolated abdominal aortic dissection (IAAD) co-occurring with an abdominal aortic aneurysm (AAA) is rather rare. The objective of this report was to discuss the adequate timing and method of surgery for this condition.

Patients: We encountered two operative cases, for which we carefully considered the timing and method of surgery. One patient underwent open repair 1 month after the onset, and the other patient underwent endovascular aneurysm repair (EVAR) 3 years after the onset.

Results: Both patients had a good postoperative recovery and are doing well 8 months after the surgery.

Conclusion: The presence of symptoms or an increase in the diameter of an AAA is important in determining the timing of intervention.

Transcatheter aortic valve replacement in patients with bicuspid aortic valves

Transcatheter aortic valve replacement (TAVR) for the treatment of severe symptomatic aortic stenosis (AS) has rapidly become the standard of care for expanding clinical indications based on the results of multiple large-scale randomized trials. Patients with bicuspid aortic valve (BAV) have been largely excluded from these trials for a variety of reasons. However, case series and registry data has shown TAVR in BAV to be a safe and efficacious alternative to surgical aortic valve replacement (SAVR) with the possible caveats of increased paravalvular regurgitation (PVR) and need for permanent pacemaker (PPM) implantation. Randomized trials are needed to determine the ultimate utility of TAVR in patients with BAV.