Membranous Septum Research Articles

The validation of four published algorithms to predict the need for pacemaker implantation after TAVR

Abstract Background The identification of patients with high risk for PPMI after TAVR might change our decision as regard the type of the prosthesis and allow more patients' acceptance for this complication. Objective: we investigated the predictors of PPMI after TF-TAVR and validated the accuracy of four published algorithms in this group of patients. Methods and results We retrospectively examined all patients who were in need for pacemaker implantation during the index hospitalisation after TAVR between 2016 and 2019. We searched for the predictors of the new PPMI after TAVR in this group of patient and compared it with a matched group of patients. Moreover, we tested the accuracy of four published algorithms. The first tested algorithm from Kaneko et al had positive predictive value (PPV), negative predictive value (NPV) and accuracy from 50%, 65% and 60% consecutively. The second tested algorithm from Jilaihawi et al had PPV, NPV and accuracy from 13.6%, 100% and 26.9% consecutively. The third tested algorithm from Maeno et al had PPV, NPV and accuracy from 37%, 56% and 45% consecutively. The forth tested algorithm from Fujiti et al had PPV, NPV and accuracy from 42%, 65% and 50% consecutively. In this study, 3 ECG-predictors (RBBB, the presence of AF and LAHB) and 3 CT-predictors (Aortic valve calcification Volume >500mm3, eccentricity index >0.25, deep valve implantation in relation to the length of membranous septum) were independent predictors of PPMI. Moreover, the rate of preimplantation ballon valivuloplasty was higher in the group with new PPMI. Using these independent predictors, the new 7 points score was developed by assigning 1 point for each one. AUC of the new score in the derivation cohort was 0.809 (95% CI 0.758–0.86), with an optimal cut-off threshold of 4 points. All other scores had AUC from 0.6 or lower. In a validation cohort of 100 patients, the predictive value of the score was confirmed (AUC, 0.72; 95% CI, 0.70–0.87; P<0.001). Conclusion The four studied score systems had low accuracy to predict new PPMI after TAVR in our cohort of patients. The new score is more complex but might be more accurate. Funding Acknowledgement Type of funding sources: None.

Real-world experience with the cusp overlap deployment technique for procedural optimization during self-expanding transcatheter aortic valve implantation: our city best practice trial

Abstract Background Aortic valve stenosis treated by transcatheter aortic valve implantation (TAVI) is a fast-growing section in interventional cardiology. Optimal implantation depth (ID) of self-expanding TAVI devices is an important condition for hemodynamic and clinical outcomes. The cusp overlap technique (COT) offers optimized fluoroscopic projections for TAVI with self-expanding devices due to improved anatomic discrimination by elongation of the left ventricular outflow tract and isolation of the non-coronary cusp (NCC) for better assessment of ID. Purpose This single-center observational study aims to investigate short-term clinical performance, safety, and efficiency outcomes regarding optimized ID in patients undergoing transfemoral TAVI with self-expanding prostheses and COT. Methods From September 2020 to December 2020, a total of 71 patients underwent TAVI with a newer-generation self-expanding device and COT. The optimal fluoroscopic projection was generated by overlapping the right (RCC) and left coronary cusps (LCC) on the multidetector computed tomography annular plane. Final ID was assessed by the arithmetic mean of distances measured from NCC and LCC to the distal prosthesis end. Outcomes were compared with a control cohort of 339 patients who underwent TAVI from January 2016 to August 2020 with a three-cusp coplanar view only during valve deployment. Results ID was significantly reduced in the COT cohort (4.3±1.9 vs. 5.0±2.3 mm; p=0.012) with better achievement of optimal ID (2–4 mm) (63.4% vs. 49.9%; p=0.03) and optimization of delta NCC-LCC ID symmetry (1.4±1.3 vs. 1.7±1.3 mm; p=0.026). The rate of pacemaker implantation following TAVI could be reduced (9.9% vs. 19.4%; p=0.05). Six of the seven patients receiving pacemaker in the COT cohort (85.7%) showed ID above membranous septum length. COT resulted in notably higher rates of device repositioning by recapturing (57.8% vs. 16.2%; p<0.001) compared to control cohort. Though, procedure time was prolonged in the COT cohort (82.0±26.5 vs. 74.9±27.5 min; p=0.05) while radiation dose and amount of contrast medium did not differ between the cohorts. No difference was observed in hemodynamic outcomes regarding transvalvular pressure gradients and at least moderate paravalvular leak. Patients implanted with COT had a shorter length of hospital stay (7.1±6.0 vs. 10.3±6.8 days; p<0.001), possibly due to a lower complication rate regarding new conduction disturbances and pacemaker implantation. Conclusion TAVI using the cusp overlap deployment technique is associated with an optimized implantation depth and a low rate of procedural complications. Therefore, a reduction of new pacemaker implantations and shortened length of hospital stay could be achieved. Funding Acknowledgement Type of funding sources: None.

Predictors of pacemaker implantation after TAVI in a registry including self, balloon and mechanical expandable valves.

The need for permanent pacemaker implantation (PPMI) is a burdensome complication of transcatheter aortic valve implantation (TAVI). The aim of our study was to evaluate different anatomical, clinical, electrocardiographic, and procedural variables associated with the development of conduction abnormalities after TAVI across the entire device spectrum.Single-center prospective cohort of consecutive patients who underwent TAVI since March 2017. Final cohort was studied to detect areas of calcium within aortic valve characterized by leaflet sector and region. Membranous septum (MS) length was assessed throughout a modified coronal view. Device selection and positioning were performed according to the operator criteria.Device selection and positioning were performed according to the operator criteria. From the 273 patients included, 57 underwent PPMI (20.8%). Univariate analysis determined right bundle branch block (RBBB), QRS duration, MS length and calcium within LVOT of non-coronary cuspid as independent predictors. After multivariable logistic regression, both RBBB (OR 6.138; 95% CI 1.23-30.73, P = 0.027) and MS length (OR 0.259; 95% CI 0.164-0.399, P < 0.005) emerged as statistically significant. As a model, they could predict PPMI in 88.7%, independently of which valve used. Youden index analysis yielded 7.69 mm as the optimal cut-off with a negative and positive predictive value of 94.7 and 71.9%, respectively.In our experience, both RBBB pattern and short membranous septum (< 8 mm) were strongly and independently associated with new permanent pacemaker implantation, regardless of the device type. Our findings suggest that this simple evolved measure of MS length may guide device selection and implantation technique and facilitate early discharge.

Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA.

DivIVA is a protein initially identified as a spatial regulator of cell division in the model organism Bacillus subtilis, but its homologues are present in many other Gram-positive bacteria, including Clostridia species. Besides its role as topological regulator of the Min system during bacterial cell division, DivIVA is involved in chromosome segregation during sporulation, genetic competence, and cell wall synthesis. DivIVA localizes to regions of high membrane curvature, such as the cell poles and cell division site, where it recruits distinct binding partners. Previously, it was suggested that negative curvature sensing is the main mechanism by which DivIVA binds to these specific regions. Here, we show that Clostridioides difficile DivIVA binds preferably to membranes containing negatively charged phospholipids, especially cardiolipin. Strikingly, we observed that upon binding, DivIVA modifies the lipid distribution and induces changes to lipid bilayers containing cardiolipin. Our observations indicate that DivIVA might play a more complex and so far unknown active role during the formation of the cell division septal membrane.

Anatomical characteristics of the membranous septum are predictive of pacemaker requirement in patients undergoing transcatheter aortic valve replacement.

We aimed to study the characteristics of the membranous septum (MS) and its relationship with the aortic valve (AoV) and aortic annulus (AA) in patients who required PPM post-TAVR. We performed a retrospective case-control study of 144 patients undergoing TAVR from 2016 to 2018. Thirty-four patients, requiring PPM implantation, were compared with 34 matched controls who did not require pacing. The total MS length, supra-annular MS (SA-MS) length, infra-annular MS (IA-MS) length, angle between the plane of the AA and MS (AA-MS), and degree of AoV calcifications (AVC) were obtained from preoperative CT. AoV prosthesis implantation depth was obtained from intra-operative fluoroscopy. There were no significant differences in valve type (self-expandable: 23 cases vs 25 controls, and balloon-expandable: 11 vs 9, p = 0.79), degree of AVC (0.65 cm3 vs 0.82 cm3, p = 0.62), or implantation depth (7.76mm vs 7.28mm, p = 0.83). Compared to controls, there was no difference in total MS length (6.68mm vs 6.06mm, p = 0.97), but the IA-MS was significantly shorter (3.64mm vs 4.56mm, p = 0.02) and the SA-MS was significantly longer (2.73mm vs 1.67mm, p = 0.02) in patients requiring PPM. Patients requiring PPM also had a larger AA-MS angle (103.5° vs 96.7°, p = 0.01). The position of the MS with respect to the AA and MS distance below the annular plane were more closely associated with post-TAVR conduction abnormalities requiring PPM than the absolute length of the MS. Patients undergoing TAVR with such anatomy have a higher risk of requiring PPM and should be monitored for developing these complications.

Perimembranous ventricular septal defect closure via ultra-minimal trans intercostal incision in children.

This study aimed to investigate the safety, feasibility and, availability of perimembranous ventricular septal defect (PmVSD) closure via a left parasternal ultra-minimal trans intercostal incision in children. From January 2015 to January 2019, 131 children with restrictive PmVSDs were enrolled in this study and successfully done in 126 patients (96.18%). PmVSDs were occluded via an ultra-minimal trans intercostal incision (≤1 cm), and the entire occlusive process was guided and monitored by TEE. A pericardium hanging technique was employed without sternal incision. PmVSDs were closed through a short delivery sheath assembled using a concentric occluder device. All patients were followed up for a period ranging from18 months to 24 months. Thirteen patients with PmVSD had aneurysm of membranous septum (AMS). Multistream (≥2) PmVSDs with AMS were found in 11 cases. After the operation, mild residual shunt beside the amplatzer occluder in one patient was found and had self-healing result during the 5-month follow-up period. Five patients transferred to ventricular septal defect repair operation under direct visualization with a cardiopulmonary bypass. One reason was ventricular fibrillation when guidewire passed the PmVSD, another was device dislocation, and others were the guidewire cannot pass through the PmVSD. PmVSDs closure using a concentric occluder via a left parasternal ultra-minimal trans intercostal incision under TEE guidance is feasible, safe, and effective in children. This approach can be considered as an alternative treatment to open-heart surgery for restrictive PmVSDs.

Computed tomography derived predictors of permanent pacemaker implantation after transcatheter aortic valve replacement: A meta-analysis.

This meta-analysis sought to assess predictors of permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) with focus on preprocedural multi-slice computed tomography (MSCT) derived data. Transcatheter aortic valve replacement (TAVR) has expanded to a well-established treatment for severe symptomatic aortic stenosis at high and intermediate surgical risk. PPI after TAVR remains one of the most frequent procedure-related complications and appears to be influenced by several factors. The authors conducted a literature search in PubMed/MEDLINE and EMBASE databases to identify studies that investigated preprocedural MSCT data and the rate of PPI following TAVR with new-generation devices. Ten observational studies (n= 2707) met inclusion criteria for the final analysis. PPI was performed in 387 patients (14.3%) after TAVR. Patients requiring PPI had a larger annulus perimeter (MD: 1.66 mm; p < .001) and a shorter membranous septum length (MD: -1.1 mm; p < .05). Concerning calcification distribution, patients with requirement for new pacemaker implantation showed increased calcification of the left coronary cusp (MD: 47.6 mm3 ; p < .001), and the total left ventricular outflow tract (MD: 24.42 mm3 ; p < .01). Lower implantation depth (MD: 0.95 mm; p < .05) and oversizing (MD: 1.52%; p < .05) were procedural predictors of PPI following TAVR. Besides the well-known impact of electrocardiographic and procedure-related factors on conduction disturbances, MSCT derived distribution of the aortic valve and left ventricular outflow tract calcification, as well as membranous septum length, are associated with an increased risk of PPI following TAVR.

Relationship between septo-valvular angle and risk of pacemaker implantation after transcatheter aortic valve implantation: a preliminary study.

Pre-transcatheter aortic valve implantation (TAVI) computed tomography (CT) has proven to be crucial in identifying pre- and post-procedural predicting factors predisposing the onset of major arrhythmias that require permanent pacemaker (PPM) implantation caused by the compressive effects of the prostheses on the conduction system at the membranous septum (MS) and the muscular crest of the interventricular septum.Our analysis aims to verify if the pre-TAVI assessment of the angle between the MS and the aortic annulus (SVA) might be a predictive factor for the onset of arrhythmias that requires PPM. Two cardiovascular specialist radiologists retrospectively and double-blind evaluated a randomized list of preprocedural CT of 57 patients who underwent TAVI with a self-expandable valve from April 2019 to February 2020. Two anatomical features were measured by readers: width of the SVA and MS length (MSL). A PPM was implanted in 18 patients (31%) after the procedure. There was no significant difference in the anatomical measurements performed between the two observers, regarding both anatomical measurements (intraclass correlation coefficient was 0.944 for the SVA and 0.774 for the MSL]. Receiver-operating characteristic curves (ROC) performed for both measurements have documented: for the SVA sensitivity 94% and Negative predictive value (NPV) 96% (area under the curve: 0.77; 95% confidence interval 0.66-0.90). The MSL ROC was not significant. The mean SVA value stratified for patients who did not undergo PPM implantation and patients who did resulted as significant (P < 0.005). Measurement of the SVA performed in preprocedural CT scans has proven to be related to the onset of major arrhythmias after TAVI requiring permanent pacemaker implantation with high sensitivity (94%) and NPV (96%).

Anatomical predictors of high grade atrioventricular conduction disorders in patients with specific pacemaker implanted after TAVI

Abstract Funding Acknowledgements Type of funding sources: None. OnBehalf STIM TAVI-MS study Background The evolution of atrioventricular conduction disorders after transcatheter aortic valve implantation (TAVI) remains poorly understood. Recent studies have identified short membranous septum (MS) length, deep implantation depth (ID) or their relation as anatomic risk of high-grade AV block and permanent pacemaker implantation. Purpose : We sought to examine whether the atrioventricular (AV) membranous septum (MS) measured by computed tomography (CT) and the depth of valve implantation measured from the final aortic angiogram could predict high-grade atrioventricular block (HG AVB) after TAVI, based on specific pacemaker memory data. Methods STIM-TAVI-MS was a prospective, multicentre observational study that enrolled patients implanted with a specific dual chamber pacemaker after TAVI, with the SafeR algorithm activated, allowing continuous monitoring of atrioventricular conduction. The primary endpoint was the occurrence of late (after Day 7) high-grade atrioventricular block(s) during the year after TAVI. We measured on CT scans the coronal MS lenght, infra-annular MS lenght and the quantification of calcifications, on the final angiogram after TAVI we measured the implant depth (ID) to identifie ΔID-MS corresponding to the difference between implant depth and MS length. The variables were compared with the occurrence of late HG-AVB on PM memory data. Results : Among 82 patients, (mean age 84,5 years ± 4,8, self-expending valve n = 24, 29,3%), n = 47 (57.3%) had ≥1 late high-grade atrioventricular block. Mean coronal MS length was 8,1 ± 2,5 mm, mean infra annular MS was 3,4 ± 3.1 mm, mean calcification volume was 93.0 ± 88, 85,5± 104 and 141,5 ± 137,5 mm3 for the noncoronary, right coronary and left coronary cusp respectively. Mean implant depth was 7,3 ± 3,3mm, and mean ΔID-MS = -0,7 ± 4,1mm. There were no association between MS length (OR = 1,06; CI 0,91 to 1,24), ID (OR = 1,6; CI 0,85 to 2,9), nor ΔID-MS (OR = 0,67; CI 0,37 to 1,23) and late HG AVB. Calcification volume were not associated with late HG AVB. Conclusion In an high risk high grade AV block population after TAVI, anatomical analysis of MS length, degree of calcification, implant depth and ΔID-MS did not predict occurrence of late (&amp;gt; day 7 after TAVI ) high grade AV Blocks. Abstract Figure. CT scan A : aortic plane, B : MS lenght

Perceval S valve empire: healing the Achilles' heel of sutureless aortic valves.

Aortic valve replacement is the treatment of choice concerning aortic valve disease. Excellent short- and long-term clinical results are reported. Patients referred for aortic valve replacement are getting older and older, so bioprosthetic valves play a more central role worldwide. However, patient comorbidities are also increased more often rendering patients unsuitable for open conventional aortic valve replacement. As a result, transcatheter aortic valve implantation has become the treatment of choice in patients at very high surgical risk. However, the percutaneous technique is related to major disadvantages provided that the diseased native valve is left in place. Its durability is also uncertain. More recently, sutureless Perceval S valve bioprosthesis has gained ground in the field of aortic stenosis therapy filling the gap between conventional aortic valve replacement and transcatheter approach. Excellent hemodynamic and clinical results are reported. Its deployment is performed under direct view and ischemic and overall operative times are significantly decreased. Five-year follow-up results are also optimal. However, the "Achilles' heel" of sutureless technology is increased rates of postoperative permanent pacemaker implantation requirement compared to conventional approach. The incidence of this complication varies in literature. Patient-related factors such as preoperative conduction disorders, older age and short membranous septum are predictors of postoperative pacemaker requirement. However, several technical modifications regarding manufacturer recommendations can be adopted to mitigate this complication. Appropriate annular decalcification, higher guiding sutures placement, reduced balloon pressure and duration and avoiding of oversizing can contribute to prevent from this complication.

The Role of CD40 in Allergic Rhinitis and Airway Remodelling.

Background Allergic rhinitis (AR) affects millions of people and is lack of effective treatment. CD40 is an important costimulatory molecule in immunity. However, few studies have focused on the role of CD40 in AR. Methods In this study, we built mouse model of chronic AR. The mice were divided into the AR, control, intravenous CD40 siRNA, and nasal CD40 siRNA groups (n = 6 each). We detected OVA-sIgE, IL-4, IL-5, IL-13, IL-10, IFN-γ, and TGF-β levels in serum and supernatant by ELISA, CD40+ splenic DCs, and Foxp3+ Tregs by flow cytometry and CD40 mRNA by RT2-PCR. We also used PAS and MT stains to assess tissue remodelling. Results (1) The OVA-sIgE, IL-4, IL-5, and IL-13 levels in the serum or supernatant of nasal septal membrane of AR mice were significantly higher than control. After treated with CD40 siRNA, those indicators were significantly decreased. The IFN-γ, IL-10, and TGF-β levels in AR mice were significantly lower than that in control and were increased by administration of CD40 siRNA. (2) AR mice had significantly fewer Foxp3+ Tregs in the spleen than control mice. After treated with CD40 siRNA, AR mice had significantly more Foxp3+ Tregs. (3) AR mice exhibited a significantly higher CD40 mRNA levels than control. Administration of CD40 siRNA significantly reduced the CD40 mRNA level. (4) The AR mice showed significantly greater collagen deposition than the control in MT staining. Applications of CD40 siRNA significantly reduced the collagen deposition in AR mice. Conclusion CD40 siRNA therapy shows promise for chronic AR as it significantly attenuated allergic symptoms and Th2-related inflammation and upregulated Foxp3+ Tregs. CD40 plays a role in tissue remodelling in AR, which can be inhibited by CD40 siRNA application.

Buoyancy control in ammonoid cephalopods refined by complex internal shell architecture

The internal architecture of chambered ammonoid conchs profoundly increased in complexity through geologic time, but the adaptive value of these structures is disputed. Specifically, these cephalopods developed fractal-like folds along the edges of their internal divider walls (septa). Traditionally, functional explanations for septal complexity have largely focused on biomechanical stress resistance. However, the impact of these structures on buoyancy manipulation deserves fresh scrutiny. We propose increased septal complexity conveyed comparable shifts in fluid retention capacity within each chamber. We test this interpretation by measuring the liquid retained by septa, and within entire chambers, in several 3D-printed cephalopod shell archetypes, treated with (and without) biomimetic hydrophilic coatings. Results show that surface tension regulates water retention capacity in the chambers, which positively scales with septal complexity and membrane capillarity, and negatively scales with size. A greater capacity for liquid retention in ammonoids may have improved buoyancy regulation, or compensated for mass changes during life. Increased liquid retention in our experiments demonstrate an increase in areas of greater surface tension potential, supporting improved chamber refilling. These findings support interpretations that ammonoids with complex sutures may have had more active buoyancy regulation compared to other groups of ectocochleate cephalopods. Overall, the relationship between septal complexity and liquid retention capacity through surface tension presents a robust yet simple functional explanation for the mechanisms driving this global biotic pattern.

Impact of Interventricular membranous septum length on pacemaker need with different Transcatheter aortic valve implantation systems

BackgroundThe need for new permanent pacemaker implantation (PPI) after Transcatheter Aortic Valve Implantation (TAVI) remains a critical issue. Membranous Septum (MS) length is associated with PPI after TAVI. The aim of this study was to identify different MS thresholds for the contemporary THV-platforms.MethodsThis retrospective, case-control study enrolled all patients who underwent a successful TAVI procedure with contemporary THV-platforms in the Erasmus University Medical Center between January 2016 and March 2020. The follow-up period for new PPI was 30 days. MS-length was determined by Computed Tomography.ResultsThe study consisted 653 TAVI patients with median age 80.6 years (IQR 74.7–84.8). New PPI occurred in 120 patients (18.4%). Patients with new PPI had a shorter MS-length (2.9 mm (IQR 2.3–4.3) vs. 4.2 mm (IQR 2.9–5.7), p < 0.001). MS-length < 3 mm identified a high-risk phenotype with 30.3% PPI-rate (OR 6.5 [95%CI 2.9–14.9]), MS-length 3–6 mm an intermediate-risk phenotype with 15.4% PPI-rate (OR 2.7 [95%CI 1.2–6.2]) and MS > 6 mm a low-risk phenotype with a 6.3% PPI-rate (reference). For the Lotus valve, there was no significant difference in PPI-rates between the high-risk (45.8%, OR 3.5 [95%CI 0.8–15.1]) and low-risk group (20%).By multivariate analysis MS-length, Agatston-score, use of Lotus valve, and ECG with first-degree AV block, RBBB or bifascular block were independent predictors for new PPI.ConclusionMS-length was an independent predictor for new PPI post-TAVI. Three phenotypes were found based on MS-length. MS < 3 mm was universally associated with a high risk for new PPI (>30%). MS > 6 mm represented a low-risk phenotype with PPI-rate < 10%. PPI-rate varied per THV type in the intermediate phenotype. PPI-rate with Lotus was high regardless of MS-length.

Biophysical Studies of Interaction between Mycobacterial SepF and FtsZ

FtsZ is the bacterial tubulin homolog that forms Z-ring, which is a dynamic ring like structure, at the site of cell division to assemble the divisome and generate constrictive force for septum formation. SepF is the key protein that anchors the constricting Z-ring to the protruding septal membrane in Mycobacterium tuberculosis, via its interaction with the intrinsically disordered C-terminal tail of FtsZ. We characterized the cytosolic component of mycobacterial SepF, and its interaction with cognate FtsZ, using negative stained electron microscopy, small angle X-ray scattering, 90 degree angle light scattering and isothermal titration calorimetry.

Tracking the Subcellular Localization of Surface Proteins in Staphylococcus aureus by Immunofluorescence Microscopy.

Surface proteins of Staphylococcus aureus and other Gram-positive bacteria play essential roles in bacterial colonization and host-microbe interactions. Surface protein precursors containing a YSIRK/GXXS signal peptide are translocated across the septal membrane at mid-cell, anchored to the cell wall peptidoglycan at the cross-wall compartment, and presented on the new hemispheres of the daughter cells following cell division. After several generations of cell division, these surface proteins will eventually cover the entire cell surface. To understand how these proteins travel from the bacterial cytoplasm to the cell surface, we describe a series of immunofluorescence microscopy protocols designed to detect the stepwise subcellular localization of the surface protein precursors: surface display (protocol A), cross-wall localization (protocol B), and cytoplasmic/septal membrane localization (protocol C). Staphylococcal protein A (SpA) is the model protein used in this work. The protocols described here are readily adapted to study the localization of other surface proteins as well as other cytoplasmic or membrane proteins in S. aureus in general. Furthermore, the protocols can be modified and adapted for use in other Gram-positive bacteria. Graphic abstract: Tracking the subcellular localization of surface proteins in S. aureus.

Aneurysmal and obstructive lesions of the left ventricular outflow: evaluation on multidetector computed tomography angiography

The left ventricular outflow is an anatomically complex region situated between the anterior leaflet of the mitral valve and the left ventricular aspect of the muscular and membranous interventricular septum. It gives rise to the aorta, provides support to the aortic valvular cusps, and houses important components of the conduction system. The left ventricular outflow handles high pressures and pressure variations and is subsequently affected by a variety of aetio-pathological conditions. Diseases involving the left ventricular outflow can be intraluminal, mural, or extramural, and the consequent complications of the lesions can be local, loco-regional, or even systemic. Appropriate evaluation requires comprehensive multimodality imaging with each modality contributing to assessment of different aspects of diagnosis, lesion characterization, local extension, prognostication for systemic complications and mortality, and the decision for the approach and type of intervention and aggressive follow-up in case non-interventional management is decided. In this review, we briefly describe the relevant anatomy and the gamut of structural abnormalities pertaining to the left ventricular outflow on multidetector computed tomography angiography.

Anatomical Predictors of Pacemaker Dependency After Transcatheter Aortic Valve Replacement.

Conduction disturbances after transcatheter aortic valve replacement (TAVR) are often transient. Limited data exist on anatomic factors predisposing to pacemaker dependency after TAVR. We sought to assess the rate and the possible predictors of pacemaker dependency after TAVR. Consecutive patients undergoing pacemaker implantation up to 30 days after TAVR between May 2014 and September 2019 were included. Baseline electrocardiographic, computed tomography, and procedural characteristics were collected, including valve implantation depth and membranous septum length, an anatomic surrogate of the distance between the aortic annulus and the His bundle. Pacemaker dependency at 30 days and 1 year and all-cause mortality during follow-up were evaluated. Of 728 TAVR patients, 112 (53.5% men; median age, 81 years) underwent pacemaker implantation after TAVR. Of these, 44.6% (50 of 112) were pacemaker dependent at 30 days and 46.7% (36 of 77) at 1 year. By multivariate analysis, independent predictors of 30-day pacemaker dependency included left ventricular outflow tract calcifications under the left coronary cusp (odds ratio, 5.69 [95% CI, 1.45-22.31]; P=0.013) and a difference between membranous septum length and implantation depth (ΔMSID) ≥3 mm (odds ratio, 7.58 [95% CI, 2.07-27.78]; P=0.002). Conversely, membranous septum length and implantation depth alone were not associated with pacemaker dependency (odds ratio, 0.79 [95% CI, 0.60-1.05]; P=0.11 and odds ratio, 1.11 [95% CI, 0.99-1.24]; P=0.08). At a median follow-up of 28.1 (11.7-48.6) months, pacemaker-dependent patients did not show a worse survival (P=0.26). Less than half of the patients undergoing pacemaker implantation after TAVR are pacemaker-dependent at midterm follow-up. ΔMSID ≥3 mm and the presence of left ventricular outflow tract calcifications under the left coronary cusp, but not membranous septum length nor implantation depth alone, are predictive of long-term pacemaker dependency after TAVR, thus influencing device selection and programming.

New insights on potential permanent pacemaker predictors in TAVR using the largest self-expandable device.

Post-procedural conduction disorders following transcatheter aortic valve replacement (TAVR) still remain frequent, especially using the largest self-expandable device (Medtronic Corevalve Evolut RTM, 34 mm, STHV-34). We, therefore, assessed previously described, predictive factors of permanent pacemaker (PPM) implantation in the context of the STHV-34, including calcification distribution, implantation depth and membranous septum length (MSL). We performed a dual centre analysis of 130 of 182 consecutive patients treated with STHV-34, further stratified into subjects without post-procedural PPM (-PPM n=100, 76.9%) and those requiring post-procedural PPM (+PPM n=30, 23.1%). These events were further analyzed by univariate and multivariate analysis according to several underlying conditions. Multivariate analysis only depicted previous right bundle branch block [RBBB; OR: 11.52 (2.63-50.44), P=0.001] and eccentricity index of the left ventricular outflow tract (LVOT-EI) >0.3 [OR: 3.07 (1.22-7.77), P=0.018] as highly predictive for PPM-need, being also confirmed by c-statistics [area under the curve (AUC) =0.68; 95% confidence interval (CI): 0.57-0.80; P=0.0025]. There was only moderate correlation of implantation depth over the MSL in terms of PPM prediction (r=0.23; P<0.0001). This study offers new insights into potential PPM predictors using the STHV-34: previous RBBB and a pronounced LVOT-EI were independent predictors of PPM, while most of the previously reported determinants failed to predict PPM-need including MSL and implantation depth.

Overcoming the transcatheter aortic valve replacement Achilles heel: conduction abnormalities-a systematic review.

Transcatheter aortic valve replacement (TAVR) has been shown to be a good alternative to surgery for treating severe symptomatic aortic stenosis (AS) across the whole range of surgical risk patients. Whereas most periprocedural TAVR complications have significantly decreased over time, conduction disturbances remain high. Approaches to decrease this shortcoming are under continuous investigation. We conducted a systematic review focusing on modifiable factors impacting post-TAVR conduction disturbances, such as balloon aortic valvuloplasty (BAV), type of new-generation transcatheter valve and implantation depth (ID). Search strategies were based on the best available evidence from each study. Primary endpoints were post-TAVR need of permanent pacemaker implantation (PPI) and new onset left bundle branch block (NOLBBB). Data from 35 studies with a total of 29,982 patients were analyzed. BAV did not negatively impact PPI rates after TAVR. In propensity-matched and randomized trials, the Evolut R valve was associated with higher rates of PPI compared to the Sapien 3 valve (25% vs. 19.2% in propensity-matched studies; 22.9% vs. 19% in a randomized trial). The Acurate Neo valve was associated with the lowest PPI rate in observational studies (10.4%), but a PPI rate similar to Sapien 3 was reported in a randomized trial (10% vs. 9%). The Portico valve system was associated with a higher PPI risk (PPI rate of 21.9% and 27.7% in propensity-matched and randomized studies, respectively). ID and its relation with the membranous septum (MS) length predicted post-TAVR conduction disturbances, particularly with Evolut R and Sapien 3 valves. Pre-TAVR BAV did not increase the risk of conduction disturbances post-TAVR. Among the new-generation transcatheter valve systems, Sapien 3 and Acurate Neo valves were associated with the lowest PPI rates followed by the Evolut and Portico valves. A deeper valve implantation and a shorter MS length determined an increased risk of conduction disturbances post-TAVR.

Predicting pacemaker implantation after TAVR with procedural CT

Abstract Background and aim The need for permanent pacemaker implantation (PPMI) is a burdensome complication of transcatheter aortic valve replacement (TAVR). Calcium distribution in the aortic-valvular complex (AVC) and, more recently, membranous septum (MS) length seem to be surrogate markers for conduction abnormalities after specific last generation balloon and self-expandable expandable valves. We sough to evaluate whether such pre-procedural association remains across the entire device spectrum. Methods Single-centre prospective study of 239 consecutive patients (140 women, median age of 84) with severe symptomatic aortic stenosis patients who underwent ECG-gated contrast-enhanced multi-detector computed tomography (MSCT) before TAVR since Jun/2017. Exclusion criteria were those with previous PPMI, previous bioprothesis, congenital bicuspid valve, and poor imaging quality. The J-score with an 850-Hounsfield unit threshold was used to detect areas of calcium in the region of interest. AVC was characterized by leaflet sector and region, using 3mensio Valves software 7.0 TM. An independent team retrospectively measured MS length blindly by determining the thinnest part of the interventricular septum in the coronal view in the better-defined systolic phase (usually at 40% of the R-R interval, Figure). Device selection (75.8% self-expandable devices, 20.1% balloon expandable, 3.1% other) and positioning were performed according to the operator criteria. Final implant depth was assessed based on the pre-release angiogram or final aortography. Results Mortality at 30-days was 1.3% and PPMI occurred in 43 patients (18%). Median MS length was 9.59mm (IQR: 3.11mm). After multivariable logistic regression analysis, MS length emerged as the single significant protective predictor for PPMI (OR: 0.14; 95% 95% CI: 0.05–0.42; p&amp;lt;0.001), independently of the device used (p&amp;lt;0.001). MS length showed strong discriminatory ability for PPMI (c-statistic 0.93; 95% CI 0.88–0.99). Sensitivity/specificity decision plots yielded an MS length of 6.9 mm as the optimal cut-off point for predicting the need for PPMI with a positive and negative predictive value of 91% and 93%, respectively (Figure). There wasn't any calcium accumulation within a specific region of AVC that independently predicted the outcome. Conclusion In our experience, a short membranous septum was strongly and independently associated with new permanent pacemaker implantation, regardless of the device type. Our findings suggest that this simple measure should be routinely made to help device selection and implantation technique. Funding Acknowledgement Type of funding source: None