Left atrial appendage thrombus and cerebrovascular events post-transcatheter aortic valve implantation.

AIMS: To elucidate the frequency and clinical impact of left atrial appendage thrombus (LAAT) in patients set for transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS: All patients undergoing TAVI between January 2014 and June 2020 with analysable multislice computed tomography (MSCT) for LAAT were included. Baseline and procedural characteristics were collected, pre-procedural MSCT's were retrospectively analysed for LAAT presence. The primary endpoint was defined as the cumulative incidence of any cerebrovascular event (stroke or transient ischaemic attack) within the first year after TAVI. A Cox proportional hazards model was used to identify predictors.A total of 1050 cases had analysable MSCT. Median age was 80 [interquartile range (IQR) 74-84], median Society of Thoracic Surgeons' Predicted Risk Of Mortality (STS-PROM) was 3.4% (IQR 2.3-5.5). Thirty-six percent were on oral anticoagulant therapy for atrial fibrillation (AF). LAAT was present in 48 (4.6%) of cases. Patients with LAAT were at higher operative risk [STS-PROM: 4.9% (2.9-7.1) vs. 3.4% (2.3-5.5), P = 0.01], had worse systolic left ventricular function [EF 52% (35-60) vs. 55% (45-65), P = 0.01] and more permanent pacemakers at baseline (35% vs. 10%, P < 0.01). All patients with LAAT had a history of AF and patients with LAAT were more often on vitamin K antagonist-treatment than patients without LAAT [43/47 (91%) vs. 232/329 (71%), P < 0.01]. LAAT [hazard ratio (HR) 2.94 (1.39-6.22), P < 0.01] and the implantation of more than one valve [HR 4.52 (1.79-11.25), P < 0.01] were independent predictors for cerebrovascular events. CONCLUSION: Patients with MSCT-identified LAAT were at higher risk for cerebrovascular events during the first year after TAVI.

Surgically implanted aortic valve bioprostheses deform after implantation: insights from computed tomography.

OBJECTIVE: Little is known about the prevalence and degree of deformation of surgically implanted aortic biological valve prostheses (bio-sAVRs). We assessed bio-sAVR deformation using multidetector-row computed tomography (MDCT). METHODS: Three imaging databases were searched for patients with MDCT performed after bio-sAVR implantation. Minimal and maximal valve ring diameters were obtained in systole and/or diastole, depending on the acquired cardiac phase(s). The eccentricity index (EI) was calculated as a measure of deformation as (1 - (minimal diameter/maximal diameter)) × 100%. EI of < 5% was considered none or trivial deformation, 5-10% mild deformation, and > 10% non-circular. Indications for MDCT and implanted valve type were retrieved. RESULTS: One hundred fifty-two scans of bio-sAVRs were included. One hundred seventeen measurements were performed in systole and 35 in diastole. None or trivial deformation (EI < 5%) was seen in 67/152 (44%) of patients. Mild deformation (EI 5-10%) was seen in 59/152 (39%) and non-circularity was found in 26/152 (17%) of cases. Overall, median EI was 5.5% (IQR 3.4-7.8). In 77 patients, both systolic and diastolic measurements were performed from the same scan. For these scans, the median EI was 6.5% (IQR 3.4-10.2) in systole and 5.1% (IQR3.1-7.6) in diastole, with a significant difference between both groups (p = 0.006). CONCLUSIONS: Surgically implanted aortic biological valve prostheses show mild deformation in 39% of cases and were considered non-circular in 17% of studied valves. KEY POINTS: • Deformation of surgically implanted aortic valve bioprostheses (bio-sAVRs) can be adequately assessed using MDCT. • Bio-sAVRs show at least mild deformation (eccentricity index > 5%) in 56% of studied cases and were considered non-circular (eccentricity index > 10%) in 17% of studied valves. • The higher deformity rate found in bio-sAVRs with (suspected) valve pathology could suggest that geometric deformity may play a role in leaflet malformation and thrombus formation similar to that of transcatheter heart valves.

Quadricuspid Neoaortic Valve in Truncus Arteriosus Type II.

Supplemental material is available for this article.

Automated Quantification of Bileaflet Mechanical Heart Valve Leaflet Angles in CT Images.

Cardiac computed tomography (CT) is a valuable tool for functional mechanical heart valve (MHV) assessment. An important aspect of bileaflet MHV assessment is evaluation and measurement of leaflet opening and closing angles. Performed manually, however, it is a laborious and time consuming task. In this paper, we propose an automated approach for bileaflet MHV leaflet angle computation. This method consists of four steps. After a one click selection of the MHV region on an axial image, an automatic MHV extraction using thresholding, and a connected component analysis based on voxel intensities is performed. Then, the MHV component (valve ring and two leaflets) positions are identified using random sample consensus and least square fitting. Finally, the angles are automatically computed based on the orientation of the components in each timeframe. Five multiphase CT scans from patients with a bileaflet MHV containing between 14 and 17 timepoints were used for development and another 15 were used for evaluation. The detected MHV components were scored for their overlap with real components as successful or unsuccessful. For successful results, the angles were compared to those measured by a radiologist. Qualitatively evaluated on a data set of 222 images, a total of 398 out of 444 angle computations (89.6%) were rated as successful. Compared to the angles measured by the radiologist, the successful angles showed a mean difference of 0.54° ± 3.63° from the manual calculations. The method provides a high success rate and an accurate computation of leaflet opening angles compared to manual measurements.

Advanced CT acquisition protocol with a third-generation dual-source CT scanner and iterative reconstruction technique for comprehensive prosthetic heart valve assessment.

OBJECTIVES: Multidetector CT (MDCT) is a valuable tool for functional prosthetic heart valve (PHV) assessment. However, radiation exposure remains a concern. We assessed a novel CT-acquisition protocol for comprehensive PHV evaluation at limited dose. METHODS: Patients with a PHV were scanned using a third-generation dual-source CT scanner (DSCT) and iterative reconstruction technique (IR). Three acquisitions were obtained: a non-enhanced scan; a contrast-enhanced, ECG-triggered, arterial CT angiography (CTA) scan with reconstructions at each 5 % of the R-R interval; and a delayed high-pitch CTA of the entire chest. Image quality was scored on a five-point scale. Radiation dose was obtained from the reported CT dose index (CTDI) and dose length product (DLP). RESULTS: We analysed 43 CT examinations. Mean image quality score was 4.1±1.4, 4.7±0.5 and 4.2±0.6 for the non-contrast-enhanced, arterial and delayed acquisitions, respectively, with a total mean image quality of 4.3±0.7. Mean image quality for leaflet motion was 3.9±1.4. Mean DLP was 28.2±17.1, 457.3±168.6 and 68.5±47.2 mGy.cm for the non-contrast-enhanced (n=40), arterial (n=43) and delayed acquisition (n=43), respectively. The mean total DLP was 569±208 mGy.cm and mean total radiation dose was 8.3±3.0 mSv (n=43). CONCLUSION: Comprehensive assessment of PHVs is possible using DSCT and IR at moderate radiation dose. KEY POINTS: • Prosthetic heart valve dysfunction is a potentially life-threatening condition. • Dual-source CT can adequately assess valve leaflet motion and anatomy. • We assessed a comprehensive protocol with three acquisitions for PHV evaluation. • This protocol is associated with good image quality and limited dose.