Enabling automated device size selection for transcatheter aortic valve implantation

The number of transcatheter aortic valve implantation (TAVI) procedures is expected to increase significantly in the coming years. Improving efficiency will become essential for experienced operators performing large TAVI volumes, while new operators will require training and may benefit from accurate support. In this work, we present a fast deep learning method that can predict aortic annulus perimeter and area automatically from aortic annular plane images. We propose a method combining two deep convolutional neural networks followed by a postprocessing step. The models were trained with 355 patients using modern deep learning techniques, and the method was evaluated on another 118 patients. The method was validated against an interoperator variability study of the same 118 patients. The differences between the manually obtained aortic annulus measurements and the automatic predictions were similar to the differences between two independent observers (paired diff. of 3.3 +/- 16.8 mm(2) vs. 1.3 +/- 21.1 mm(2) for the area and a paired diff. of 0.6 +/- 1.7 mm vs. 0.2 +/- 2.5 mm for the perimeter). The area and perimeter were used to retrieve the suggested prosthesis sizes for the Edwards Sapien 3 and the Medtronic Evolut device retrospectively. The automatically obtained device size selections accorded well with the device sizes selected by operator 1. The total analysis time from aortic annular plane to prosthesis size was below one second. This study showed that automated TAVI device size selection using the proposed method is fast, accurate, and reproducible. Comparison with the interobserver variability has shown the reliability of the strategy, and embedding this tool based on deep learning in the preoperative planning routine has the potential to increase the efficiency while ensuring accuracy

Clinical Valve Thrombosis and Subclinical Leaflet Thrombosis Following Transcatheter Aortic Valve Replacement: Is There a Need for a Patient-Tailored Antithrombotic Therapy?

Transcatheter aortic valve replacement (TAVR) has become an established therapeutic option for patients with symptomatic, severe aortic valve stenosis at increased surgical risk. Antithrombotic therapy after TAVR aims to prevent transcatheter heart valve (THV) thrombosis, in which two different entities have to be recognized: clinical valve thrombosis and subclinical leaflet thrombosis. In clinical valve thrombosis, obstructive thrombus formation leads to an increased transvalvular gradient, often provoking heart failure symptoms. Subclinical leaflet thrombosis is most often an incidental finding, characterized by a thin layer of thrombus covering the aortic side of one or more leaflets; it is also referred to as Hypo-Attenuating Leaflet Thickening (HALT) as described on multi-detector computed tomography (MDCT) imaging. This phenomenon may also affect leaflet motion and is then classified as Hypo-Attenuation affecting Motion (HAM). Even in case of HAM, the transvalvular pressure gradient remains within normal range and does not provoke heart failure symptoms. Whereas, clinical valve thrombosis requires treatment, the clinical impact and need for intervention in subclinical leaflet thrombosis is still uncertain. Oral anticoagulant therapy protects against and resolves both clinical valve thrombosis and subclinical leaflet thrombosis; however, large-scale randomized clinical trials studying different antithrombotic strategies after TAVR are still under way. This review article summarizes the currently available data within the field of transcatheter aortic valve/leaflet thrombosis and discusses the need for a patient tailored antithrombotic approach

Prevalence, associated factors and management implications of left ventricular outflow tract obstruction in Takotsubo cardiomyopathy: a two-year, two-center experience

Background: Some patients with Takotsubo cardiomyopathy (TTC) develop cardiogenic shock due to left ventricular outflow tract (LVOT) obstruction -there is, however, a paucity of data regarding this condition. Methods: Prevalence, associated factors and management implications of LVOT obstruction in TTC was explored, based on two-year data from two Belgian heart centres. Results: A total of 32 patients with TTC were identified out of 3,272 patients presenting with troponin-positive acute coronary syndrome. In six patients diagnosed with TTC (19%), a significant LVOT obstruction was detected by transthoracic echocardiography. Patients with LVOT obstruction were older and had more often septal bulging, and presented more frequently in cardiogenic shock as compared to those without LVOT obstruction (P < 0.05). Moreover, all patients with LVOT obstruction showed systolic anterior motion (SAM) of the anterior mitral valve leaflet, which was associated with a higher grade of mitral regurgitation (2.2 +/- 0.7 vs. 1.0 +/- 0.6, P< 0.001). Adequate therapeutic management including fluid resuscitation, cessation of inotropic therapy, intravenous beta-blocker, and the use of intra-aortic balloon pump resulted in non-inferior survival in TTC patients with LVOT obstruction as compared to those without LVOT obstruction. Conclusions: TTC is complicated by LVOT obstruction in approximately 20% of cases. Older age, septal bulging, SAM-induced mitral regurgitation and hemodynamic instability are associated with this condition. Timely and accurate diagnosis of LVOT obstruction by echocardiography is key to successful management of these TTC patients with LVOT obstruction and results in a non-inferior outcome as compared to those patients without LVOT obstruction

Percutaneous Transaxillary versus Surgically- Assisted Transsubclavian TAVR: A Single Center Experience

Background: Transfemoral access is the standard approach for transcatheter aortic valve replacement (TAVR). However, an important proportion of TAVR patients may not be considered for transfemoral access because of anatomic reasons - for these patients, an alternative access route must be considered. The objective of this study was to assess the safety and efficacy of percutaneous transaxillary TAVR as compared to surgically assisted transsubclavian TAVR and to report the feasibility of next-day discharge following this percutaneous approach. Methods: Since January 2019, all transaxillary TAVR at our institution were performed using a standardized percutaneous approach - this was compared to our prior experience with transsubclavian TAVR via surgical cut down. Results: Sixty-four patients underwent transsubclavian/axillary TAVR since 2014: 40 surgically assisted transsubclavian (2014-2018) and 24 fully percutaneous transaxillary TAVR (2019-2020). Both groups had similar baseline characteristics. In the surgically assisted TAVR group, six major vascular complications were encountered and six patients were rehospitalized within 30 days after TAVR vs. no patients with a major vascular complication and one patient rehospitalized within 30 days in the percutaneous transaxillary group. Hospitalization was significantly shorter for patients treated by percutaneous vs. surgical approach (1.2 vs. 4.4 days; p &lt; 0.001). Twenty out of 24 percutaneous transaxillary TAVR patients (83%) were discharged the day after TAVR. Conclusion: Percutaneous transaxillary TAVR is a safe and effective treatment option for patients not suitable for transfemoral TAVR. Significant reduction in hospital length-of-stay was noted in percutaneous transaxillary vs. surgically assisted transsubclavian TAVR

Guiding 3D U-nets with signed distance fields for creating 3D models from images

Morphological analysis of the left atrial appendage is an important tool to assess risk of ischemic stroke. Most deep learning approaches for 3D segmentation is guided by binary labelmaps, which results in voxelized segmentations unsuitable for morphological analysis. We propose to use signed distance fields to guide a deep network towards morphologically consistent 3D models. The proposed strategy is evaluated on a synthetic dataset of simple geometries, as well as a set of cardiac computed tomography images containing the left atrial appendage. The proposed method produces smooth surfaces with a closer resemblance to the true surface in terms of segmentation overlap and surface distance.Comment: MIDL 2019 [arXiv:1907.08612