Ventricular septal defect following mitral valve replacement

Mitral valve surgery (MVS), with repair preferred to replacement, is a common procedure for the treatment of severe primary mitral regurgitation related to leaflet prolapse. Structural complications after MVS include left ventricular outflow obstruction, paravalvular leak and atrial septal defect. Intraoperative transoesophageal echocardiography and predischarge transthoracic echocardiography (TTE) specifically screen for these complications. Ventricular septal defect (VSD), a known complication after aortic valve surgery, is rarely reported after MVS. Recently, unsuccessful valvuloplasty prior to replacement was suggested as a risk factor. We present such a case and explore mechanisms with advanced cardiac imaging. In this case, the patient was found to have an elongated membranous septum that likely predisposed her to septal injury. Finally, we provide guidance on specific transoesophageal/transthoracic echocardiography views to avoid a missed diagnosis.

Predictors for new-onset conduction block in patients with pure native aortic regurgitation after transcatheter aortic valve replacement with a new-generation self-expanding valve (VitaFlow Liberty™): a retrospective cohort study

BACKGROUND

New-generation self-expanding valves can improve the success rate of transcatheter aortic valve replacement (TAVR) for severe pure native aortic regurgitation (PNAR). However, predictors of new-onset conduction block post-TAVR using new-generation self-expanding valves in patients with PNAR remain to be established. Therefore, this study aimed to identify predictors of new-onset conduction block post-TAVR using new-generation self-expanding valves (VitaFlow Liberty™) in patients with PNAR.

METHODS

In this retrospective cohort study, patients were categorized into pacemaker and non-pacemaker groups based on their need for new postoperative permanent pacemaker implantation (PPI). Based on the postoperative presence of either new-onset complete left bundle branch block (cLBBB) or high-grade atrioventricular block (AVB), patients were further classified into conduction disorder and non-conduction disorder groups. Laboratory, echocardiographic, computed tomography, preoperative and postoperative electrocardiography, and procedural and clinical data were collected immediately after TAVR and during hospitalization and compared between the groups. Multivariate logistic regression analysis was performed incorporating the significant variables from the univariate analyses.

RESULTS

This study examined 68 consecutive patients with severe PNAR who underwent TAVR. In 20 patients, a permanent pacemaker was fitted postoperatively. Multivariate logistic regression analysis revealed an association between the need for postoperative PPI and preoperative complete right bundle branch block (cRBBB) or first-degree AVB, as well as a non-tubular left ventricular outflow tract (LVOT). In addition, valve implantation depth and angle of aortic root were independent predictors of new-onset cLBBB or high-grade AVB developing post-TAVR. The predictive value of valve implantation depth and angle of aortic root was further supported by receiver operating characteristic curve analysis results.

CONCLUSIONS

In patients with PNAR undergoing TAVR using self-expanding valves, preoperative cRBBB or first-degree AVB and a non-tubular LVOT were indicators of a higher likelihood of PPI requirement. Moreover, deeper valve implantation depth and greater angle of aortic root may be independent risk factors for new-onset cLBBB or high-grade AVB post-TAVR. Valve implantation depth and angle of aortic root values may be used to predict the possibility of new cLBBB or high-grade AVB post-TAVR.

[Evaluation of Changes in Membranous Septum Length during the Cardiac Cycle and by Measurement Methods Using the Preoperative CT for Transcatheter Aortic Valve Replacement: A Single-center Cross-sectional Study]

PURPOSE

The purpose of this study was to evaluate the changes in membranous septum (MS) length during the cardiac cycle and by measurement methods using the preoperative computed tomography (CT) images for transcatheter aortic valve replacement (TAVR).

METHOD

Among 34 consecutive patients who underwent preoperative contrast-enhanced CT for TAVR, we measured MS lengths by three measurement methods (coronal, stretched, and reformatted coronal view method) at 10% intervals in the cardiac cycle.

RESULT

MS lengths differed between the three measurement methods in all cardiac phases. Moderate correlations were observed between the MS lengths measured by the coronal view method and the other two methods. In contrast, strong correlations were observed between the MS lengths measured by the stretched view method and the reformatted coronal view method. The frequencies of the minimum and maximum MS lengths during the cardiac cycle tended to be highest at R-R 90% and R-R 30%, respectively. The median MS lengths at R-R 90% were smaller than those at R-R 30% in all measurement methods.

CONCLUSION

The MS length in patients undergoing contrast-enhanced CT for TAVR varies notably depending on the cardiac cycle and measurement methods. When evaluating MS length, it is crucial to consider the measurement method and to perform measurements during diastole in order to evaluate the minimum value during the cardiac cycle.

Impact of membranous septum length on pacemaker need with different transcatheter aortic valve replacement systems: The INTERSECT registry

BACKGROUND

New permanent pacemaker implantation (new-PPI) remains a compelling issue after Transcatheter Aortic Valve Replacement (TAVR). Previous studies reported the relationship between a short MS length and the new-PPI post-TAVR with a self-expanding THV. However, this relationship has not been investigated in different currently available THV. Therefore, the aim of this study was to investigate the association between membranous septum (MS)-length and new-PPI after TAVR with different Transcatheter Heart Valve (THV)-platforms.

METHODS

We included patients with a successful TAVR-procedure and an analyzable pre-procedural multi-slice computed tomography. MS-length was measured using a standardized methodology. The primary endpoint was the need for new-PPI within 30 days after TAVR.

RESULTS

In total, 1811 patients were enrolled (median age 81.9 years [IQR 77.2-85.4], 54% male). PPI was required in 275 patients (15.2%) and included respectively 14.2%, 20.7% and 6.3% for Sapien3, Evolut and ACURATE-THV(p ​< ​0.01). Median MS-length was significantly shorter in patients with a new-PPI (3.7 ​mm [IQR 2.2-5.1] vs. 4.1 ​mm [IQR 2.8-6.0], p ​= ​<0.01). Shorter MS-length was a predictor for PPI in patients receiving a Sapien3 (OR 0.87 [95% CI 0.79-0.96], p ​= ​<0.01) and an Evolut-THV (OR 0.91 [95% CI 0.84-0.98], p ​= ​0.03), but not for an ACURATE-THV (OR 0.99 [95% CI 0.79-1.21], p ​= ​0.91). By multivariable analysis, first-degree atrioventricular-block (OR 2.01 [95% CI 1.35-3.00], p = <0.01), right bundle branch block (OR 8.33 [95% CI 5.21-13.33], p = <0.01), short MS-length (OR 0.89 [95% CI 0.83-0.97], p ​< ​0.01), annulus area (OR 1.003 [95% CI 1.001-1.005], p ​= ​0.04), NCC implantation depth (OR 1.13 [95% CI 1.07-1.19] and use of Evolut-THV(OR 1.54 [95% CI 1.03-2.27], p ​= ​0.04) were associated with new-PPI.

CONCLUSION

MS length was an independent predictor for PPI across different THV platforms, except for the ACURATE-THV. Based on our study observations within the total cohort, we identified 3 risk groups by MS length: MS length ≤3 ​mm defined a high-risk group for PPI (>20%), MS length 3-7 ​mm intermediate risk for PPI (10-20%) and MS length > 7 ​mm defined a low risk for PPI (<10%). Anatomy-tailored-THV-selection may mitigate the need for new-PPI in patients undergoing TAVR.

Tricuspid Valve Imaging and Right Ventricular Function Analysis Using Cardiac CT and MRI

Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMR) can reveal the detailed anatomy and function of the tricuspid valve and right ventricle (RV). Quantification of tricuspid regurgitation (TR) and analysis of RV function have prognostic implications. With the recently available transcatheter treatment options for diseases of the tricuspid valve, evaluation of the tricuspid valve using CT and CMR has become important in terms of patient selection and procedural guidance. Moreover, CT enables post-procedural investigation of the causes of valve dysfunction, such as pannus or thrombus. This review describes the anatomy of the tricuspid valve and CT and CMR imaging protocols for right heart evaluation, including RV function and TR analyses. We also demonstrate the pre-procedural planning for transcatheter treatment of TR and imaging of postoperative complications using CT.

Multimodality Imaging of the Anatomy of the Aortic Root

The aortic root has long been considered an inert unidirectional conduit between the left ventricle and the ascending aorta. In the classical definition, the aortic valve leaflets (similar to what is perceived for the atrioventricular valves) have also been considered inactive structures, and their motion was thought to be entirely passive—just driven by the fluctuations of ventricular–aortic gradients. It was not until the advent of aortic valve–sparing surgery and of transcatheter aortic valve implantation that the interest on the anatomy of the aortic root again took momentum. These new procedures require a systematic and thorough analysis of the fine anatomical details of the components of the so-called aortic valve apparatus. Although holding and dissecting cadaveric heart specimens remains an excellent method to appreciate the complex “three-dimensional” nature of the aortic root, nowadays, echocardiography, computed tomography, and cardiac magnetic resonance provide excellent images of cardiac anatomy both in two- and three-dimensional format. Indeed, modern imaging techniques depict the aortic root as it is properly situated within the thorax in an attitudinally correct cardiac orientation, showing a sort of “dynamic anatomy”, which admirably joins structure and function. Finally, they are extensively used before, during, and after percutaneous structural heart disease interventions. This review focuses on the anatomy of the aortic root as revealed by non-invasive imaging techniques.

First in situ 3D visualization of the human cardiac conduction system and its transformation associated with heart contour and inclination

Current advanced imaging modalities with applied tracing and processing techniques provide excellent visualization of almost all human internal structures in situ; however, the actual 3D internal arrangement of the human cardiac conduction system (CCS) is still unknown. This study is the first to document the successful 3D visualization of the CCS from the sinus node to the bundle branches within the human body, based on our specialized physical micro-dissection and its CT imaging. The 3D CCS transformation by cardiac inclination changes from the standing to the lying position is also provided. Both actual dissection and its CT image-based simulation identified that when the cardiac inclination changed from standing to lying, the sinus node shifted from the dorso-superior to the right outer position and the atrioventricular conduction axis changed from a vertical to a leftward horizontal position. In situ localization of the human CCS provides accurate anatomical localization with morphometric data, and it indicates the useful correlation between heart inclination and CCS rotation axes for predicting the variable and invisible human CCS in the living body. Advances in future imaging modalities and methodology are essential for further accurate in situ 3D CCS visualization.

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.

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

Background The 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. Methods This 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. Results The 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. Conclusion MS-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.

Three-dimensional visualization of the bovine cardiac conduction system and surrounding structures compared to the arrangements in the human heart

In the human heart, the atrioventricular node is located toward the apex of the triangle of Koch, which is also at the apex of the inferior pyramidal space. It is adjacent to the atrioventricular portion of the membranous septum, through which it penetrates to become the atrioventricular bundle. Subsequent to its penetration, the conduction axis is located on the crest of the ventricular septum, sandwiched between the muscular septum and ventricular component of the membranous septum, where it gives rise to the ramifications of the left bundle branch. In contrast, the bovine conduction axis has a long non-branching component, which penetrates into a thick muscular atrioventricular septum having skirted the main cardiac bone and the rightward half of the non-coronary sinus of the aortic root. It commonly gives rise to both right and left bundle branches within the muscular ventricular septum. Unlike the situation in man, the left bundle branch is long and thin before it branches into its fascicles. These differences from the human heart, however, have yet to be shown in three-dimensions relative to the surrounding structures. We have now achieved this goal by injecting contrast material into the insulating sheaths that surround the conduction network, evaluating the results by subsequent computed tomography. The fibrous atrioventricular membranous septum of the human heart is replaced in the ox by the main cardiac bone and the muscular atrioventricular septum. The apex of the inferior pyramidal space, which in the bovine, as in the human, is related to the atrioventricular node, is placed inferiorly relative to the left ventricular outflow tract. The bovine atrioventricular conduction axis, therefore, originates from a node itself located inferiorly compared to the human arrangement. The axis must then skirt the non-coronary sinus of the aortic root prior to penetrating the thicker muscular ventricular septum, thus accounting for its long non-branching course. We envisage that our findings will further enhance comparative anatomical research.

Periprocedural Predictors of New-Onset Conduction Abnormalities After Transcatheter Aortic Valve Replacement

BACKGROUND

New-onset conduction abnormalities (CAs) following transcatheter aortic valve replacement (TAVR) are associated with hospital rehospitalization and long-term mortality, but available predictors are sparse. This study sought to determine clinical predictors of new-onset left bundle branch block (LBBB) and new permanent pacemaker (PPM) implantation in patients undergoing TAVR.

METHODS AND RESULTS

We enrolled 290 patients who received SAPIEN 3 (Edwards Lifesciences, Irvine, CA, USA; n=217) or Evolut R (Medtronic, Minneapolis, MN, USA; n=73) from a prospective registry at Nouvel Hôpital Civil, Strasbourg, France between September 2014 and February 2018. Of 242 patients without pre-existing LBBB, 114 (47%) experienced new-onset LBBB and/or new PPM implantation. A difference between membranous septal length and implantation depth (∆MSID) was the only predictor of CAs for both types of valves. In the multivariate analysis, PR interval and ∆MSID remained as sole predictors of CAs. The risk for adverse clinical events, including all-cause death, myocardial infarction, stroke, and heart failure hospitalization, was higher for patients with CAs as compared with patients without CAs (hazard ratio: 2.10; 95% confidence interval: 1.26 to 3.57; P=0.004).

CONCLUSIONS

Computed tomography assessment of membranous septal anatomy and implantation depth predicted CAs after TAVR with new-generation valves. Future studies are required to identify whether adjustment of the implantation depth can reduce the risk of CAs and adverse clinical outcomes.

Diagnostic accuracy of cardiac magnetic resonance imaging for cardiac sarcoidosis in complete heart block patients implanted with magnetic resonance-conditional pacemaker

BACKGROUND

Cardiac magnetic resonance (CMR) imaging has become the principal noninvasive imaging modality for the diagnosis of cardiac sarcoidosis (CS) patients. This study aimed to determine the diagnostic performance of CMR imaging for CS in new-onset complete heart block (CHB) patients implanted with magnetic resonance-conditional pacemaker (MRCP).

METHODS

Fifty CHB patients implanted with MRCP were enrolled in this study. Clinical CS was diagnosed if there was a histological diagnosis of extra-cardiac sarcoidosis in patients with CHB based on the consensus statement; clinical CS was the reference standard. The diagnostic performance of CMR sequences, including cine magnetic resonance imaging (MRI), increased T2-weighted signal (T2WS), and late gadolinium enhancement (LGE), for clinical CS was investigated. We also compared the diagnostic performance of CMR sequences between the entire left ventricle (LV) and the basal septum, which involves the electrical pathway of atrioventricular conduction.

RESULTS

In total, 8 of the 50 patients with CHB were confirmed to have extra-cardiac sarcoidosis and were diagnosed with clinical CS. The accuracy, sensitivity, and specificity of LGE in the basal septum and entire LV were 94%, 100%, and 93% and 80% (p = 0.023), 100% (p = 1.00), and 76% (p = 0.023), respectively. The accuracy, sensitivity, and specificity of increased T2WS and cine MRI in the basal septum were 94%, 75%, and 98% and 90%, 38%, and 100%, respectively. There was no statistical difference between the entire LV and the basal septum for the diagnostic performance of increased T2WS and cine MRI.

CONCLUSIONS

CMR can be a diagnostic tool for evaluating clinical CS in patients with CHB implanted with MRCP. LGE in the basal septum might provide the overall best diagnostic performance for clinical CS with CHB.

Variations in rotation of the aortic root and membranous septum with implications for transcatheter valve implantation

Objective

It is intuitive to suggest that knowledge of the variation in the anatomy of the aortic root may influence the outcomes of transcatheter implantation of the aortic valve (TAVI). We have now assessed such variation.

Methods

We used 26 specimens of normal hearts and 78 CT data sets of adults with a mean age of 64±15 years to measure the dimensions of the membranous septum and to assess any influence played by rotation of the aortic root, inferring the relationship to the atrioventricular conduction axis.

Results

The aortic root was positioned centrally in the majority of both cohorts, although with significant variability. For the cadaveric hearts, 14 roots were central (54%), 4 clockwise-rotated (15%) and 8 counterclockwise-rotated (31%). In the adult CT cohort, 44 were central (56%), 21 clockwise-rotated (27%) and 13 counterclockwise-rotated (17%). A mean angle of 15.5° was measured relative to the right fibrous trigone in the adult CT cohort, with a range of −32° to 44.7°. The dimensions of the membranous septum were independent of rotation. Fibrous continuity between the membranous septum and the right fibrous trigone increased with counterclockwise to clockwise rotation, implying variation in the relationship to the atrioventricular conduction axis.

Conclusions

The central fibrous body is wider, providing greater fibrous support, in the setting of clockwise rotation of the aortic root. Individuals with this pattern may be more vulnerable to conduction damage following TAVI. Knowledge of such variation may prove invaluable for risk stratification.