Transcatheter Aortic Valve Replacement for Bicuspid vs. Tricuspid Aortic Stenosis among Patients at Low Surgical Risk in China: From the Multicenter National NTCVR Database

BACKGROUND

This study aims to compare the outcomes of transcatheter aortic valve replacement (TAVR) with self-expandable valves for bicuspid aortic valve (BAV) vs. tricuspid aortic valve (TAV) stenosis patients who are at low surgical risk.

METHODS

Participants were enrolled from 36 centers in China between January 2017 and December 2021. The primary endpoint event was all-cause mortality and all stroke at 30 days.

RESULTS

Among 389 patients at low surgical risk that underwent TAVR, 229 patients were BAV stenosis (mean age, 72.9 years; 65.1% men). There was no significant difference in the rate of all-cause death between two populations at 30 days. However, the rate of all stroke was significantly higher in the BAV group at 30 days (3.3% vs. 0%; odds ratio (OR), 0.97 (95% confidence interval (CI), 0.94 to 0.99); p = 0.044). By multivariate logistic regression analysis, trans-carotid access was associated with a higher all stroke rate at 30 days (OR, 29.20 (95% CI, 3.97 to 215.1); p = 0.001).

CONCLUSIONS

In this national registry-based study, patients treated for BAV vs. TAV stenosis had no significant difference in all-cause mortality at 30 days, but trans-carotid access was associated with a higher all stroke rate after TAVR at 30 days.

Technical Success after Transcatheter Aortic Valve Replacement for Bicuspid versus Tricuspid Aortic Stenosis

Background: Comparative data of the Valve Academic Research Consortium (VARC-3)-defined technical success between bicuspid versus tricuspid aortic stenosis (AS) remain lacking. Aims: We sought to compare the technical success and other clinical outcomes between patients with bicuspid and tricuspid AS receiving transcatheter aortic valve replacement. Methods: A registration-based analysis was performed for 402 patients (211 and 191 cases of bicuspid and tricuspid AS, respectively). The primary outcome was VARC-3-defined technical success. Additional analysis was performed to assess outcomes for up to one year between the two groups. Results: Bicuspid AS patients tended to be younger (74 years vs. 77 years; p < 0.001) with a lower Society of Thoracic Surgeons score (4.4% vs. 5.4%; p = 0.003). Bicuspid AS patients showed a lower prevalence of hypertension and peripheral vascular diseases. Technical failure was encountered in 17.7% of these patients, driven primarily by the high incidence of second valve implantation. The technical success rates were comparable between the bicuspid and tricuspid AS groups (82.5% vs. 82.2%, p = 0.944). Chronic kidney disease (CKD) and larger sinotubular junctional diameter (STJ) were identified as predictors of technical failure, whereas CKD, impaired left ventricular ejection fraction (LVEF), along with larger STJ, were predictors of cardiac technical failure. Technical failure was associated with an increased risk of all-cause mortality at 30 days and 1 year, as evidenced by the Cox multivariable analysis. Conclusions: No significant differences were observed in the technical success rates and most clinical outcomes between the bicuspid and tricuspid AS groups. Technical failure conferred an increased risk for both 30-day and 1-year all-cause mortalities.

Assessment of aortic valve area on cardiac computed tomography in symptomatic bicuspid aortic stenosis: Utility and differences from Doppler echocardiography

Background

In this study, we investigate the utility of geometric orifice area (GOA) on cardiac computed tomography (CT) and differences from effective orifice area (EOA) on Doppler echocardiography in patients with bicuspid aortic stenosis (AS).

Methods

A total of 163 patients (age 64 ± 10 years, 56.4% men) with symptomatic bicuspid AS who were referred for surgery and underwent both cardiac CT and echocardiography within 3 months were studied. To calculate the aortic valve area, GOA_CT was measured by multiplanar CT planimetry, and EOA_Echo was calculated by the continuity equation with Doppler echocardiography. The relationships between GOA_CT and EOA_Echo and patient symptom scale, biomarkers, and left ventricular (LV) functional variables were analyzed.

Results

There was a significant but modest correlation between EOA_Echo and GOA_CT (r = 0.604, p < 0.001). Both EOA_Echo and GOA_CT revealed significant correlations with mean pressure gradient and peak transaortic velocity, and the coefficients were higher in EOA_Echo than in GOA_CT. EOA_Echo of 1.05 cm² and GOA_CT of 1.25 cm² corresponds to hemodynamic cutoff values for diagnosing severe AS. EOA_Echo was well correlated with the patient symptom scale and log NT-pro BNP, but GOA_CT was not. In addition, EOA_Echo had a higher correlation coefficient with estimated LV filling pressure and LV global longitudinal strain than GOA_CT.

Conclusion

GOA_CT can be used to evaluate the severity of bicuspid AS. The threshold for GOA_CT for diagnosing severe AS should be higher than that for EOA_Echo. However, EOA_Echo is still the method of choice because EOA_Echo showed better correlations with clinical and functional variables than GOA_CT.

Transcatheter Aortic Valve Implantation for Severe Bicuspid Aortic Stenosis - 2 Years Follow up Experience From India

Background

Transcatheter aortic valve implantation (TAVI) is challenging in bicuspid aortic valve (BAV) anatomy. The patients are young, morphological phenotypes are many, calcium burden is high and there are technical challenges for best outcomes. Observational studies and registries are available with favorable data and experiences from around the world sharing methodologies and algorithms for sizing and implantation. We, therefore, analysed our data of procedural and in-hospital outcomes of TAVI in Bicuspid Aortic Valve cases performed at two high volume centres in India and their follow up for two years.

Methods and Results

The data were collated and analysed from two centres (Fortis Escorts Heart Institute, New Delhi and Apollo Hospitals, Chennai) in India for patients who underwent TAVI in a BAV anatomy. It included a total of 70 cases from 2 centres. All symptomatic severe AS patients more than and equal to 65 years having bicuspid anatomy were included in the study irrespective of their STS score. Patients under 65 years of age were advised TAVI only if they were at high risk for open heart surgery. These patients were followed for a period of 2 years and the data were analysed. Pre TAVI imaging tools utilised were 2D echo, transthoracic echocardiography (TTE), trans oesophageal echocardiography (TEE), and ECG gated multi slice CT (MSCT) scan imaging. MSCT was utilised for confirmation of the anatomy and classifying the morphological type of valve, measuring, and evaluating all anatomic determinants of aortic root complex for planning the procedure and choice of the valve and its size. Sizing in balloon expanding valve (BEV) and self-expanding valve sizing (SEV) were based primarily on annulus area and perimeter, respectively. The SEV used in our study were the Core Valve and Evolut R (Medtronic, United States) and the BEVs included Sapien3 (Edwards Lifesciences, United States) and Myval (Meril Lifesciences, India). The BAV cohort constituted 24.4% of the total 287 TAVI cases, followed up for 2 years. The mean age of these patients was 72 years. The incidence of male patients was 68.57% and female patients was 31.4%. The Sievers type 1 included 78.5%, type 0 were 21.4% of the cases and there was no case of type 2 in the study. The procedural success was to the tune of 98%. Patients with normal left ventricular ejection fraction (LVEF) improved their symptoms class after TAVI and remained so at 2 years follow up. The poor LVEF subset of patients did not have heart failure admissions and also had improvement in their symptom status. The peak-to-peak aortic valve gradient decreased to 0 mmHg at the end of the procedure in most of the cases. The mean pressure gradient (PG) across the new valve ranged between 0 and 15 mmHg and the aortic valve area (AVA) was close to 2 cm². These numbers were consistent at 2 years follow up. Significant paravalvular leak (PVL) 24.28% was seen immediately after deployment of the valve in heavily calcified anatomy but it reduced to mild or trivial PVL after post-dilation and one patient needed a second valve to treat PVL. No patient had more than mild PVL with either type of valve at the end of the procedure. Permanent pacemaker implantation (PPI) was required in 11.4% of the patients within 24 h to 7 days of the procedure. No one needed a PPI in the 2 year follow up. Coronary occlusion did not happen to any patient. No patient had a disabling stroke. Non-disabling stroke was seen in 10% of cases and mostly in the first week or 30 days of the procedure and the incidence was more with BEV (14%) as compared to SEV (8%). There was one case of valve embolisation after 24 h of the procedure, which needed a surgical valve replacement. There was no case of annular injury or injury to other parts of the aortic root complex. Two cases had access vessel (femoral artery) thrombosis at end of the procedure and a third patient had proglide related residual stenosis. Two cases had acute kidney injury and needed dialysis. There was no major bleeding complication in any patient. Peri procedural mortality occurred in two patients. Valve thrombosis was seen in one patient after 3 months, which was treated with oral anticoagulation. Valve degeneration and failure or infective endocarditis were not seen in any patient.

Conclusion

The patients with BAV stenosis who underwent TAVI in this study had good procedural success rates and clinical outcomes. The haemodynamics achieved with both SEV and BEV were good at 2 years. The rates of PVL, PPI, and stroke are similar to that of many other studies and registries. PPI rate and non-disabling stroke incidence appear to be higher similar to many studies done. There was no case of coronary occlusion in the study. Meticulous CT analysis of the aortic root complex, selection of appropriate type and size of the valve, and best implantation practices along with cerebral protection will probably be the key to safer and more successful TAVI in this population.

The Predictors of Conduction Disturbances Following Transcatheter Aortic Valve Replacement in Patients With Bicuspid Aortic Valve: A Multicenter Study

Objective: To evaluate the predictors of new-onset conduction disturbances in bicuspid aortic valve patients using self-expanding valve and identify modifiable technical factors. Background: New-onset conduction disturbances (NOCDs), including complete left bundle branch block and high-grade atrioventricular block, remain the most common complication after transcatheter aortic valve replacement (TAVR). Methods: A total of 209 consecutive bicuspid patients who underwent self-expanding TAVR in 5 centers in China were enrolled from February 2016 to September 2020. The optimal cut-offs in this study were generated from receiver operator characteristic curve analyses. The infra-annular and coronal membranous septum (MS) length was measured in preoperative computed tomography. MSID was calculated by subtracting implantation depth measure on postoperative computed tomography from infra-annular MS or coronal MS length. Results: Forty-two (20.1%) patients developed complete left bundle branch block and 21 (10.0%) patients developed high-grade atrioventricular block after TAVR, while 61 (29.2%) patients developed NOCDs. Coronal MS <4.9 mm (OR: 3.08, 95% CI: 1.63-5.82, p = 0.001) or infra-annular MS <3.7 mm (OR: 2.18, 95% CI: 1.04-4.56, p = 0.038) and left ventricular outflow tract perimeter <66.8 mm (OR: 4.95 95% CI: 1.59-15.45, p = 0.006) were powerful predictors of NOCDs. The multivariate model including age >73 years (OR: 2.26, 95% CI: 1.17-4.36, p = 0.015), Δcoronal MSID <1.8 mm (OR: 7.87, 95% CI: 2.84-21.77, p < 0.001) and prosthesis oversizing ratio on left ventricular outflow tract >3.2% (OR: 3.42, 95% CI: 1.74-6.72, p < 0.001) showed best predictive value of NOCDs, with c-statistic = 0.768 (95% CI: 0.699-0.837, p < 0.001). The incidence of NOCDs was much lower (7.5 vs. 55.2%, p < 0.001) in patients without Δcoronal MSID <1.8 mm and prosthesis oversizing ratio on left ventricular outflow tract >3.2% compared with patients who had these two risk factors. Conclusion: The risk of NOCDs in bicuspid aortic stenosis patients could be evaluated based on MS length and prosthesis oversizing ratio. Implantation depth guided by MS length and reducing the oversizing ratio might be a feasible strategy for heavily calcified bicuspid patients with short MS.