Angulation and curvature of aortic landing zone affect implantation depth in transcatheter aortic valve implantation.

In transcatheter aortic valve implantation (TAVI), final device position may be affected by device interaction with the whole aortic landing zone (LZ) extending to ascending aorta. We investigated the impact of aortic LZ curvature and angulation on TAVI implantation depth, comparing short-frame balloon-expanding (BE) and long-frame self-expanding (SE) devices. Patients (n = 202) treated with BE or SE devices were matched based on one-to-one propensity score. Primary endpoint was the mismatch between the intended (HPre) and the final (HPost) implantation depth. LZ curvature and angulation were calculated based on the aortic centerline trajectory available from pre-TAVI computed tomography. Total LZ curvature ( k L Z , t o t ) and LZ angulation distal to aortic annulus ( α L Z , D i s t a l ) were greater in the SE compared to the BE group (P < 0.001 for both). In the BE group, HPost was significantly higher than HPre at both cusps (P < 0.001). In the SE group, HPost was significantly deeper than HPre only at the left coronary cusp (P = 0.013). At multivariate analysis, α L Z , D i s t a l was the only independent predictor (OR = 1.11, P = 0.002) of deeper final implantation depth with a cut-off value of 17.8°. Aortic LZ curvature and angulation significantly affected final TAVI implantation depth, especially in high stent-frame SE devices reporting, upon complete release, deeper implantation depth with respect to the intended one.

Performance and outcomes of the SAPIEN 3 Ultra RESILIA transcatheter heart valve in the OCEAN-TAVI registry.

BACKGROUND: Data on the performance of the latest-generation SAPIEN 3 Ultra RESILIA (S3UR) valve in patients who undergo transcatheter aortic valve replacement (TAVR) are scarce. AIMS: We aimed to assess the clinical outcomes, including valve performance, of the S3UR. METHODS: Registry data of 618 consecutive patients with S3UR and of a historical pooled cohort of 8,750 patients who had a SAPIEN 3 (S3) valve and underwent TAVR were collected. The clinical outcomes and haemodynamics, including patient-prosthesis mismatch (PPM), were compared between the 2 groups and in a propensity-matched cohort. RESULTS: The incidence of in-hospital death, vascular complications, and new pacemaker implantation was similar between the S3UR and the S3 groups (allp>0.05). However, both groups showed significant differences in the degrees of paravalvular leakage (PVL) (none-trivial: 87.0% vs 78.5%, mild: 12.5% vs 20.5%, ≥moderate: 0.5% vs 1.1%; p<0.001) and the incidence of PPM (none: 94.3% vs 85.1%, moderate: 5.2% vs 12.8%, severe: 0.5% vs 2.0%; p<0.001). The prevalence of a mean pressure gradient ≥20 mmHg was significantly lower in the S3UR group (1.6% vs 6.2%; p<0.001). Better haemodynamics were observed with the smaller 20 mm and 23 mm S3UR valves. The results were consistent in a matched cohort of patients with S3UR and with S3 (n=618 patients/group). CONCLUSIONS: The S3UR has equivalent procedural complications to the S3 but with lower rates of PVL and significantly better valve performance. The better valve performance of the S3UR, particularly in smaller valve sizes, overcomes the remaining issue of balloon-expandable valves after TAVR.

Defining high bleeding risk in patients undergoing transcatheter aortic valve implantation: a VARC-HBR consensus document.

The identification and management of patients at high bleeding risk (HBR) undergoing transcatheter aortic valve implantation (TAVI) are of major importance, but the lack of standardised definitions is challenging for trial design, data interpretation, and clinical decision-making. The Valve Academic Research Consortium for High Bleeding Risk (VARC-HBR) is a collaboration among leading research organisations, regulatory authorities, and physician-scientists from Europe, the USA, and Asia, with a major focus on TAVI-related bleeding. VARC-HBR is an initiative of the CERC (Cardiovascular European Research Center), aiming to develop a consensus definition of TAVI patients at HBR, based on a systematic review of the available evidence, to provide consistency for future clinical trials, clinical decision-making, and regulatory review. This document represents the first pragmatic approach to a consistent definition of HBR evaluating the safety and effectiveness of procedures, devices and drug regimens for patients undergoing TAVI..

New-onset atrial fibrillation detected by ambulatory ECG monitoring after transcatheter aortic valve implantation.

BACKGROUND: Little is known about the occurrence of subclinical new-onset atrial fibrillation (NOAF) after transcatheter aortic valve implantation (TAVI). AIMS: We aimed to evaluate the incidence, predictors, and clinical impact of subclinical NOAF after TAVI. METHODS: This was a multicentre study, including patients with aortic stenosis (AS) and no previous atrial fibrillation undergoing TAVI, with continuous ambulatory electrocardiogram (AECG) monitoring after TAVI. RESULTS: A total of 700 patients (79±8 years, 49% female, Society of Thoracic Surgeons score 2.9% [1.9-4.0]) undergoing transarterial TAVI were included (85% balloon-expandable valves). AECG was started 1 (0-1) day after TAVI (monitoring time: 14121314 days). NOAF was detected in 49 patients (7%), with a median duration of 185 (43-421) minutes (atrial fibrillation burden of 0.7% [0.3-2.8]). Anticoagulation was started in 25 NOAF patients (51%). No differences were found in baseline or procedural characteristics, except for a higher AS severity in the NOAF group (peak gradient: no NOAF: 71.9±23.5 mmHg vs NOAF: 85.2±23.8 mmHg; p=0.024; mean gradient: no NOAF: 44.4±14.7 mmHg vs NOAF: 53.8±16.8 mmHg; p=0.004). In the multivariable analysis, the baseline mean transaortic gradient was associated with a higher risk of NOAF after TAVI (odds ratio 1.04, 95% confidence interval: 1.01-1.06 for each mmHg; p=0.006). There were no differences between groups in all-cause mortality (no NOAF: 4.7% vs NOAF: 0%; p=0.122), stroke (no NOAF: 1.4% vs NOAF: 2.0%; p=0.723), or bleeding (no NOAF: 1.9% vs NOAF: 4.1%; p=0.288) from the 30-day to 1-year follow-up. CONCLUSIONS: NOAF detected with AECG occurred in 7% of TAVI recipients and was associated with a higher AS severity. NOAF detection determined the start of anticoagulation therapy in about half of the patients, and it was not associated with an increased risk of clinical events at 1-year follow-up.

Assess the Outcomes of Transcatheter Aortic Valve Replacement in Bicuspid Valve with Mixed Disease versus Predominant Aortic Stenosis.

Purpose: In mixed aortic valve disease (MAVD), the results of transcatheter aortic valve replacement (TAVR) are conflicting. There is limited data on the outcomes of TAVR in patients with bicuspid aortic valve (BAV) and MAVD. The objective of this study is to compare outcomes after TAVR in BAV patients with MAVD and predominant aortic stenosis (PAS). Patients and Methods: Patients with BAV who underwent TAVR between January 2016 and April 2023 were included. The primary outcome was device success. The secondary endpoints were periprocedural mortality and other complications as defined by the Valve Academic Research Consortium-3 (VARC-3). Propensity score matching was used to minimize potential confounding. Results: A total of 262 patients were included in this study, 83 of whom had MAVD. The median age was 72 years, and 55.7% were male. The baseline comorbidity risk files were comparable between the two groups. Patients with MAVD had more mitral regurgitation, tricuspid regurgitation and pulmonary hypertension, larger annular and left ventricular outflow tract dimensions, and more severe calcification than PAS. In the unmatched population, MAVD patients had similar device success rate (69.9% vs 79.9%, P=0.075) and 30-day mortality (3.6% vs 3.4%, P=1) compared to PAS. Propensity score matching resulted in 66 patient pairs. Device success rate were still comparable in the matched population. Other clinical outcomes, including stroke, bleeding (type 2-4), major vascular complications, acute kidney injury (stage 2-4) and permanent pacemaker implantation, were comparable between the two groups. Multivariable logistic regression analysis did not show MAVD to be an independent negative predictor of device success. At one year, survival was similar between patients with MAVD and those with PAS. Conclusion: For the bicuspid valve, patients with MAVD had a more challenging anatomy. MAVD patients associated with comparable 30-day clinical outcomes after TAVR compared to PAS patients in patients with BAV.

[Perioperative stroke after aortic valve replacement for aortic stenosis - incidence, risk factors and short-term outcome].

INTRODUCTION: One of the most serious complications of surgical aortic valve replacement (SAVR) is stroke that can result in increased rates of complications, morbidity and mortality postoperatively. The aim of this study was to investigate incidence, risk factors and short-term outcome in a well defined cohort of SAVR-patients. MATERIALS AND METHOD: A retrospective study on 740 consecutive aortic stenosis patients who underwent SAVR in Iceland 2002-2019. Patients with stroke were compared with non-stroke patients; including preoperative risk factors of cardiovascular disease, echocardiogram-results, rate of early postoperative complications other than stroke and 30 day mortality. RESULTS: Mean age was 71 yrs (34% females) with 57% of the patients receiving stented bioprosthesis, 31% a stentless Freestyle®-valve and 12% a mechanical valve. Mean EuroSCORE-II was 3.6, with a maximum preop-gradient of 70 mmHg and an estimated valvular area of 0.73 cm2. Thirteen (1.8%) patients were diagnosed with stroke where hemiplegia (n=9), loss of consciousness (n=3) and/or aphasia (n=4) were the most common presenting symptoms. In 70% of cases the neurological symptoms resolved or disappeared in the first weeks and months after surgery. Only one patient out of 13 died within 30-days (7.7%). Stroke-patients had significantly lower BMI than non-stroke patients, but other risk factors of cardiovascular diseases, intraoperative factors or the rate of other severe postoperative complications than stroke were similar between groups. Total length of stay was 14 days vs. 10 days median, including 2 vs. 1 days in the ICU, in the stroke and non-stroke-groups, respectively. CONCLUSIONS: The rate of stroke after SAVR was low (1.8%) and in line with other similar studies. Although a severe complication, most patients with perioperative stroke survived 30 days postoperatively and in majority of cases neurological symptoms recovered.

An interactive, online decision aid assessing patient goals and preferences for treatment of aortic stenosis to support physician-led shared decision-making: Early feasibility pilot study.

BACKGROUND: Guidelines recommend shared decision making when choosing treatment for severe aortic stenosis but implementation has lagged. We assessed the feasibility and impact of a novel decision aid for severe aortic stenosis at point-of-care. METHODS: This prospective multi-site pilot cohort study included adults with severe aortic stenosis and their clinicians. Patients were referred by their heart team when scheduled to discuss treatment options. Outcomes included shared decision-making processes, communication quality, decision-making confidence, decisional conflict, knowledge, stage of decision making, decision quality, and perceptions of the tool. Patients were assessed at baseline (T0), after using the intervention (T1), and after the clinical encounter (T2); clinicians were assessed at T2. Before the encounter, patients reviewed the intervention, Aortic Valve Improved Treatment Approaches (AVITA), an interactive, online decision aid. AVITA presents options, frames decisions, clarifies patient goals and values, and generates a summary to use with clinicians during the encounter. RESULTS: 30 patients (9 women [30.0%]; mean [SD] age 70.4 years [11.0]) and 14 clinicians (4 women [28.6%], 7 cardiothoracic surgeons [50%]) comprised 28 clinical encounters Most patients [85.7%] and clinicians [84.6%] endorsed AVITA. Patients reported AVITA easy to use [89.3%] and helped them choose treatment [95.5%]. Clinicians reported the AVITA summary helped them understand their patients' values [80.8%] and make values-aligned recommendations [61.5%]. Patient knowledge significantly improved at T1 and T2 (p = 0.004). Decisional conflict, decision-making stage, and decision quality improved at T2 (p = 0.0001, 0.0005, and 0.083, respectively). Most patients [60%] changed treatment preference between T0 and T2. Initial treatment preferences were associated with low knowledge, high decisional conflict, and poor decision quality; final preferences were associated with high knowledge, low conflict, and high quality. CONCLUSIONS: AVITA was endorsed by patients and clinicians, easy to use, improved shared decision-making quality and helped patients and clinicians arrive at a treatment that reflected patients' values. TRIAL REGISTRATION: Trial ID: NCT04755426, Clinicaltrials.gov/ct2/show/NCT04755426.

Moderate Aortic Valve Stenosis Is Associated With Increased Mortality Rate and Lifetime Loss: Systematic Review and Meta-Analysis of Reconstructed Time-to-Event Data of 409 680 Patients.

BACKGROUND: The mortality risk attributable to moderate aortic stenosis (AS) remains incompletely characterized and has historically been underestimated. We aim to evaluate the association between moderate AS and all-cause death, comparing it with no/mild AS (in a general referral population and in patients with heart failure with reduced ejection fraction). METHODS AND RESULTS: A systematic review and pooled meta-analysis of Kaplan-Meier-derived reconstructed time-to-event data of studies published by June 2023 was conducted to evaluate survival outcomes among patients with moderate AS in comparison with individuals with no/mild AS. Ten studies were included, encompassing a total of 409 680 patients (11 527 with moderate AS and 398 153 with no/mild AS). In the overall population, the 15-year overall survival rate was 23.3% (95% CI, 19.1%-28.3%) in patients with moderate AS and 58.9% (95% CI, 58.1%-59.7%) in patients with no/mild aortic stenosis (hazard ratio [HR], 2.55 [95% CI, 2.46-2.64]; P<0.001). In patients with heart failure with reduced ejection fraction, the 10-year overall survival rate was 15.5% (95% CI, 10.0%-24.0%) in patients with moderate AS and 37.3% (95% CI, 36.2%-38.5%) in patients with no/mild AS (HR, 1.83 [95% CI, 1.69-2.0]; P<0.001). In both populations (overall and heart failure with reduced ejection fraction), these differences correspond to significant lifetime loss associated with moderate AS during follow-up (4.4 years, P<0.001; and 1.9 years, P<0.001, respectively). A consistent pattern of elevated mortality rate associated with moderate AS in sensitivity analyses of matched studies was observed. CONCLUSIONS: Moderate AS was associated with higher risk of death and lifetime loss compared with patients with no/mild AS.

Comparison of Contemporary Treatment Strategies in Patients With Cardiogenic Shock Due to Severe Aortic Stenosis.

BACKGROUND: The aims of this study were to understand the incidence and outcomes of patients with cardiogenic shock (CS) due to severe aortic stenosis (AS), and the impact of conventional treatment strategies in this population. METHODS AND RESULTS: All patients admitted to the Cleveland Clinic cardiac intensive care unit between January 1, 2010 and December 31, 2021 with CS were retrospectively identified and categorized into those with CS in the setting of severe AS versus CS without AS. The impact of various treatment strategies on mortality was further assessed. We identified 2754 patients with CS during the study period, of whom 216 patients (8%) had CS in the setting of severe AS. Medical management was associated with the highest 30-day mortality when compared with either balloon aortic valve replacement or aortic valve replacement (surgical or transcatheter aortic valve replacement) (hazard ratio, 3.69 [95% CI, 2.04-6.66]; P<0.0001). Among patients who received transcatheter therapy, 30-day mortality was significantly higher in patients who received balloon aortic valvuloplasty versus transcatheter aortic valve replacement (26% versus 4%, P=0.02). Both surgical and transcatheter aortic valve replacement had considerably lower mortality than medical management and balloon aortic valvuloplasty at 30 days and 1 year (P<0.05 for both comparisons). CONCLUSIONS: CS due to severe AS is associated with high in-hospital and 30-day mortality, worse compared with those with CS without AS. In suitable patients, urgent surgical aortic valvuloplasty or transcatheter aortic valve replacement is associated with favorable short- and long-term outcomes. Although balloon aortic valvuloplasty may be used to temporize patients with CS in the setting of severe AS, mortality is ≈50% if not followed by definitive aortic valve replacement within 90 days.

Differential Effect of Aortic Valve Replacement for Severe Aortic Stenosis on Hyperemic and Resting Epicardial Coronary Pressure Indices.

BACKGROUND: Coronary pressure indices to assess coronary artery disease are currently underused in patients with aortic stenosis due to many potential physiological effects that might hinder their interpretation. Studies with varying sample sizes have provided us with conflicting results on the effect of transcatheter aortic valve replacement (TAVR) on these indices. The aim of this meta-analysis was to study immediate and long-term effects of TAVR on fractional flow reserve (FFR) and nonhyperemic pressure ratios (NHPRs). METHODS AND RESULTS: Lesion-specific coronary pressure data were extracted from 6 studies, resulting in 147 lesions for immediate change in FFR analysis and 105 for NHPR analysis. To investigate the long-term changes, 93 lesions for FFR analysis and 68 for NHPR analysis were found. Lesion data were pooled and compared with paired t tests. Immediately after TAVR, FFR decreased significantly (-0.0130±0.0406 SD, P: 0.0002) while NHPR remained stable (0.0003±0.0675, P: 0.9675). Long-term after TAVR, FFR decreased significantly (-0.0230±0.0747, P: 0.0038) while NHPR increased nonsignificantly (0.0166±0.0699, P: 0.0543). When only borderline NHPR lesions were considered, this increase became significant (0.0249±0.0441, P: 0.0015). Sensitivity analysis confirmed our results in borderline lesions. CONCLUSIONS: TAVR resulted in small significant, but opposite, changes in FFR and NHPR. Using the standard cut-offs in patients with severe aortic stenosis, FFR might underestimate the physiological significance of a coronary lesion while NHPRs might overestimate its significance. The described changes only play a clinically relevant role in borderline lesions. Therefore, even in patients with aortic stenosis, an overtly positive or negative physiological assessment can be trusted.

Role of aortic valve replacement in moderate aortic stenosis: a 10-year outcomes study.

OBJECTIVE: Patients with moderate aortic stenosis (AS) exhibit high morbidity and mortality. Limited evidence exists on the role of aortic valve replacement (AVR) in this patient population. To investigate the benefit of AVR in moderate AS on survival and left ventricular function. METHODS: In a retrospective cohort study, patients with moderate AS between 2008 and 2016 were selected from the Cleveland Clinic echocardiography database and followed until 2018. Patients were classified as receiving AVR or managed medically (clinical surveillance). All-cause and cardiovascular mortality were assessed by survival analyses. Temporal haemodynamic and structural changes were assessed with longitudinal analyses using linear mixed effects models. RESULTS: We included 1421 patients (mean age, 75.3±5.4 years and 39.9% women) followed over a median duration of 6 years. Patients in the AVR group had lower risk of all-cause (adjusted HR (aHR)=0.51, 95% CI: 0.34 to 0.77; p=0.001) and cardiovascular mortality (aHR=0.50, 95% CI: 0.31 to 0.80; p=0.004) compared with those in the clinical surveillance group irrespective of sex, receipt of other open-heart surgeries and underlying malignancy. These findings were seen only in those with preserved left ventricular ejection fraction (LVEF) ≥50%. Further, patients in the AVR group had a significant trend towards an increase in LVEF and a decrease in right ventricular systolic pressure compared with those in the clinical surveillance group. CONCLUSIONS: In patients with moderate AS, AVR was associated with favourable clinical outcomes and left ventricular remodelling.

Hyperglycemia-simulating environment attenuated experimentally induced calcification in cultured human aortic valve interstitial cells.

Objectives: The role of diabetes mellitus as a risk factor for the development of calcific aortic valve disease has not been fully clarified. Aortic valve interstitial cells (VICs) have been suggested to be crucial for calcification of the valve. Induced calcification in cultured VICs is a good in vitro model for aortic valve calcification. The purpose of this study was to investigate whether increased glucose levels increase experimentally induced calcification in cultured human VICs. Design: VICs were isolated from explanted calcified aortic valves after valve replacement. Osteogenic medium induced calcification of cultured VICs at different glucose levels (5, 15, and 25 mM). Calcium deposits were visualized using Alizarin Red staining and measured spectrophotometrically. Results: The higher the glucose concentration, the lower the level of calcification. High glucose (25 mM) reduced calcification by 52% compared with calcification at a physiological (5 mM) glucose concentration (correlation and regression analysis: r = -0.55, p = .025 with increased concentration of glucose). Conclusions: In vitro hyperglycemia-like conditions attenuated calcification in VICs. High glucose levels may trigger a series of events that secondarily stimulate calcification of VICs in vivo.

First-time surgical aortic valve replacement: nationwide trends and outcomes from The Netherlands Heart Registration.

OBJECTIVES: The aim of this study was to describe trends and outcomes for patients undergoing surgical aortic valve replacement (SAVR) in the Netherlands. METHODS: The Netherlands Heart Registration database was used to report the number and outcomes of isolated, primary SAVR procedures performed from 2007 to 2018 in adult patients. RESULTS: A total of 17 142 procedures were included, of which 77.9% were performed using a biological prosthesis and 21.0% with a mechanical prosthesis. Median logistic EuroSCORE I decreased from 4.6 [interquartile range (IQR) 2.4-7.7] to 4.0 (IQR 2.6-6.0). The 120-day mortality decreased from 3.3% in 2007 to 0.7% in 2018. The median duration of follow-up was 76 months (IQR 53-111). Ten-year survival, when adjusted for age, EuroSCORE I and body surface area, was 72.4%, and adjusted 10-year freedom from reinvervention was 98.1%. Additional analysis for patients under the age of 60 showed no difference between patients treated with a biological or mechanical prosthesis in adjusted 10-year survival, 89.7% vs 91.9±%, respectively (P = 0.25), but a significant difference in adjusted 10-year freedom from reintervention, 90.0±% vs 95.9%, respectively (P < 0.01). CONCLUSIONS: Between 2007 and 2018, age and risk profile of patients undergoing SAVR decreased, especially for patients treated with a biological prosthesis. The 120-day mortality decreased over time. Patients undergoing SAVR nowadays have a risk of 120-day mortality of <1% and 10-year freedom from valve-related reintervention of >95%.

Surgical Technique And Clinical Implications Of Transcatheter Aortic Valve Bioprosthesis Explantation.

There has been a worldwide rapid adoption of transcatheter aortic valve replacement (TAVR) as an alternative to surgical aortic valve replacement (SAVR) for patients with severe aortic stenosis. Currently, more TAVR explants with SAVRs are performed than TAVR-in TAV. TAVR explantation is a technically hazardous procedure mainly due to significant aortic neo-endothelialization which incorporates the TAVR valve. Surgical techniques for TAVR explantation are not well established and surgeon experience at present is limited. In this manuscript, we describe our technique for surgical explantation of transcatheter aortic bioprosthesis. Familiarity with the procedure and its clinical implications is essential for all cardiac surgeons.

Epicardial fat volume is associated with primary coronary slow-flow phenomenon in patients with severe aortic stenosis undergoing transcatheter valve implantation.

BACKGROUND: Primary coronary slow flow (CSF) is defined as delayed opacification of the distal epicardial vasculature during coronary angiography in the absence of relevant coronary artery stenoses. Microvascular disease is thought to be the underlying cause of this pathology. Epicardial fat tissue (EFT) is an active endocrine organ directly surrounding the coronary arteries that provides pro-inflammatory factors to the adjacent tissue by paracrine and vasocrine mechanisms. The aim of the present study was to investigate a potential association between EFT and primary CSF and whether EFT can predict the presence of primary CSF. METHODS: Between 2016 and 2017, n = 88 patients with high-grade aortic stenosis who were planned for transcatheter aortic valve implantation (TAVI) were included in this retrospective study. EFT volume was measured by pre-TAVI computed tomography (CT) using dedicated software. The presence of primary CSF was defined based on the TIMI frame count from the pre-TAVI coronary angiograms. RESULTS: Thirty-nine of 88 TAVI patients had CSF (44.3%). EFT volume was markedly higher in patients with CSF (142 ml [IQR 107-180] vs. 113 ml [IQR 89-147]; p = 0.009) and was strongly associated with the presence of CSF (OR 1.012 [95%CI 1.002-1.021]; p = 0.014). After adjustment, EFT volume was still an independent predictor of CSF (OR 1.016 [95%CI 1.004-1.026]; p = 0.009). CONCLUSION: Primary CSF was independently associated with increased EFT volume. Further studies are needed to validate this finding and elucidate whether a causal relationship exists.

Interventricular septal thickness on cardiac computed tomography as a novel risk factor for conduction disturbances in patients undergoing transcatheter aortic valve replacement.

AIMS: We examined whether thickness of the basal muscular interventricular septum (IVS), as measured by pre-procedural computed tomography (CT), could be used to identify the risk of conduction disturbances following transcatheter aortic valve replacement (TAVR). The IVS is a pivotal region of the electrical conduction system of the heart where the atrioventricular conduction axis is located. METHODS AND RESULTS: Included were 78 patients with severe aortic stenosis who underwent CT imaging prior to TAVR. The thickness of muscular IVS was measured in the coronal view, in systolic phases, at 1, 2, 5, and 10 mm below the membranous septum (MS). The primary endpoint was a composite of conduction disturbance following TAVR. Conduction disturbances occurred in 24 out of 78 patients (30.8%). Those with conduction disturbances were significantly more likely to have a thinner IVS than those without conduction disturbances at every measured IVS level (2.98 ± 0.52 mm vs. 3.38 ± 0.52 mm, 4.10 ± 1.02 mm vs. 4.65 ± 0.78 mm, 6.11 ± 1.12 mm vs. 6.88 ± 1.03 mm, and 9.72 ± 1.95 mm vs. 10.70 ± 1.55 mm for 1, 2, 5 and 10 mm below MS, respectively, P < 0.05 for all). Multivariable logistic regression analysis showed that pre-procedural IVS thickness (<4 mm at 2 mm below the MS) was a significant independent predictor of post-procedural conduction disturbance (adjOR 7.387, 95% CI: 2.003-27.244, P = 0.003). CONCLUSION: Pre-procedural CT assessment of basal IVS thickness is a novel predictive marker for the risk of conduction disturbances following TAVR. The IVS thickness potentially acts as an anatomical barrier protecting the underlying conduction system from mechanical compression during TAVR.