Hypoattenuated Leaflet Thickening Research Articles

Comparison of apixaban versus aspirin for the prevention of latent bioprosthetic aortic valve thrombosis: study protocol for a prospective randomized trial.

The optimal antithrombotic strategy early after aortic valve replacement surgery with a biological valve remains controversial due to lack of high-quality evidence. Either oral anticoagulants or acetylsalicylic acid should be considered for the first 3 months. Hypo-attenuated leaflet thickening on cardiac computed tomography has been associated with latent bioprosthetic valve thrombosis and may be prevented with anticoagulation. We hypothesize that anticoagulation with apixaban is superior to single antiplatelet therapy with acetylsalicylic acid in reducing hypo-attenuated leaflet thickening of bioprosthetic aortic valve prostheses. In this prospective, open-label, randomized trial, patients undergoing isolated aortic valve replacement surgery with rapid deployment bioprosthetic valves will be randomized. The treatment group will receive 5 mg of apixaban twice a day for the first 3 months and 100 mg of acetylsalicylic acid thereafter. The control group will be administered 100 mg of acetylsalicylic acid once a day, indefinitely. After the 3-month treatment period, a contrast-enhanced electrocardiogram-gated cardiac computed tomography will be performed to identify hypo-attenuated leaflet thickening of the bioprosthetic valve. The primary objective of the study is to assess the impact of apixaban on the prevention of hypo-attenuated leaflet thickening at 3 months. The secondary and exploratory endpoints will be clinical outcomes and safety profiles of the two strategies. Antithrombotic therapy after aortic valve replacement is used to prevent valve thrombosis and systemic thromboembolism. Latent bioprosthetic valve thrombosis is a precursor of clinically significant prosthetic valve dysfunction or thromboembolic events. The hallmark feature of latent bioprosthetic valve thrombosis is hypo-attenuated leaflet thickening on cardiac computed tomography. Subclinical leaflet thrombosis occurs frequently in bioprosthetic aortic valves, more commonly in transcatheter than in surgical valves. There is no evidence on the effect of direct oral anticoagulants on the incidence of hypo-attenuated leaflet thickening after surgical aortic valve replacement with rapid deployment bioprostheses. ClinicalTrials.gov NCT06184113. Registered on December 28, 2023.

One-year initial efficacy and safety outcomes of the premounted dry-pericardium Vienna self-expandable transcatheter aortic valve system: A first-in-human VIVA feasibility study.

The dry-pericardium Vienna transcatheter aortic valve system is repositionable and retrievable, already premounted on the delivery system, eliminating the need for assembly and crimping of the device before valve implantation. The VIVA first-in-human feasibility study, a prospective, nonrandomized, single-center trial, evaluated the Vienna aortic valve in 10 patients with severe symptomatic aortic stenosis, who were at intermediate or high surgical risk. This study, registered at ClinicalTrials.gov (NCT04861805), focused on the safety, feasibility, clinical and hemodynamic performance of the Vienna system up to 1-year follow-up. The mean patient age was 79 ± 5 years, 60% male. Valve sizes used: 26 mm (10%), 29 mm (30%), 31 mm (60%). Key hemodynamic improvements were significant: mean aortic valve pressure gradient (mmHg) decreased from 48.7 to 8.1, aortic valve area (cm2) increased from 0.75 to 1.91, and maximum jet velocity through the aortic valve (m/s) decreased from 4.41 to 1.95 (p < 0.0001). No moderate/severe paravalvular leakage was observed, and computed tomography scans revealed no evidence of hypo-attenuated leaflet thickening. The study recorded one life-threatening bleeding event, two cases requiring postprocedural pacemaker implantation, and three ischemic events, with only one causing lasting neurological impairment. Importantly, there were no cases of cardiovascular mortality and only one noncardiovascular death, which was confirmed as unrelated to the device. The study indicates the Vienna valve as a potential option for severe symptomatic aortic stenosis, designed to streamline the procedure and potentially lower healthcare costs by reducing resource and equipment needs, also procedural errors. Further research is essential to thoroughly evaluate its safety and efficacy.

Risk Factors for Early HALT after Transfemoral TAVI

Objective: To investigate the risk factors of hypoattenuated leaflet thickening (HALT) in the early stage after transfemoral transcatheter aortic valve implantation (TAVI). Methods: Patients who underwent transfemoral TAVI in the Affiliated Hospital of Qingdao University from January 2021 to June 2023 were selected. According to the results of four-dimensional computed tomography (4DCT), patients were divided into HALT group and non-HALT group. The perioperative data of the two groups were collected to find the risk factors of HALT in the early postoperative period. Results: A total of 100 patients underwent TAVI operation via femoral artery, 2 died after operation, 1 discharged due to cerebral complication, and 2 patients had incomplete 4DCT data. The data of 95 patients were completely collected, including 56 males and 39 females, with an average age of (72.0 ± 6.7) years and a body mass index of (24.0 ± 3.7) kg/m2. 10 patients had HALT, the incidence was 10.5%. 85 patients were in the non-HALT group, including 52 males (61.2%). 10 patients were in the HALT group, 4 cases were male (40%). There were no significant differences in age, sex, body mass index (BMI), hypertension, diabetes, chronic obstructive pulmonary disease (COPD), brain complications, coronary heart disease, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF) and operation time between the two groups. And the differences between the two groups in perioperative white blood cell, neutrophil, lymphocyte and platelet counts, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and creatinine were not significant. Compared with the non-HALT group, patients in the HALT group had a higher proportion of isolated aortic insufficiency, a lower proportion of post dilatation after valve release, and a higher proportion of valves with skirts. Conclusion: Isolated aortic insufficiency, without post dilatation after valve release, and use of valves with skirt are associated with early HALT after transfemoral TAVI.

Early thrombus formation including hypo-attenuated leaflet thrombosis after surgical bioprosthetic aortic valve replacement.

To assess the occurrence, predictors, and outcomes of hypo-attenuated leaflet thickening (HALT) and thrombus outside the prosthetic valve following surgical aortic valve replacement. A total of 118 patients underwent surgical aortic valve replacement with bioprosthetic valves between July 2020 and June 2022. Sixty-two (52.5%) patients, which is a fairly high number of patients, underwent cardiac computed tomography and transthoracic echocardiography one week after surgery. Patients were divided into two groups, those with HALT (n = 14) and those without HALT (n = 48). Of the 62 patients who underwent cardiac computed tomography, HALT was observed in 14 (22.5%) patients during the very early postoperative phase. Reduced leaflet motion was observed in two of the 14 patients. The low-attenuation areas were located outside the prosthetic valve in 10 cases (71.4%) in the HALT group and in 14 cases (29.2%) in the non-HALT group. More than 50% of patients (57.1%) with HALT and 79.2% without HALT were administered warfarin. Neither in-hospital deaths nor postoperative thromboembolic events were observed during hospitalization. No patient had a mean pressure gradient > 20mmHg in either group. HALT was observed in one-fifth of the cases after surgical aortic valve replacement during the very early postoperative phase in an institution wherein administration of continuous heparin infusion after surgery is a standard practice. HALT did not affect the early prognosis or incidence of cerebral infarction.

Incidence and impact of hypoattenuated leaflet thickening following aortic valve replacement using a glycerol-preserved bioprosthesis

Incidence and impact of hypoattenuated leaflet thickening following aortic valve replacement using a glycerol-preserved bioprosthesis

Utility of Photon Counting CT in Transcatheter Structural Heart Disease Interventions

Photon counting Computed Tomography (PCCT) is an innovative technology that utilizes a semiconductor detector and assigns x-ray photons to specific energy bins. PCCT features include ultra high-resolution, multi-energy binning, higher signal of iodine, lower artifacts, lower noise, and geometric radiation dose efficiency. These advantages may be highly beneficial in pre- and post-procedural assessment of transcatheter structural heart disease (SHD) interventions. Ultra-high resolution improves visualization of device structure and subtle findings such as hypoattenuated leaflet thickening, small vegetations and paravalvular leaks. High resolution also improves the evaluation of heavily calcified and stented coronary arteries, which are prevalent in high-risk transcatheter aortic valve replacement (TAVR) population. Visualization of heavily calcified coronary arteries and access vessels can also be improved by using multienergy calcium separation or high-energy virtual monoenergetic images (VMIs). PCCT allows use of low dose of iodinated contrast in severe renal dysfunction, due to inherent higher contrast-to-noise ratio of iodine, availability of a high-pitch helical mode and low-energy VMIs. High-energy VMIs can decrease artifacts including calcium blooming, beam hardening and metallic artifacts. Iodine maps enable quantification of extracellular volume without need for a non-contrast scan, facilitating the identification of cardiomyopathies like cardiac amyloidosis. Moreover, calcium score can be obtained from virtual non contrast (VNC) images derived from CT angiographic images. Additionally, VNC and iodine maps can characterize incidentally encountered lesions such as thrombus. In this article, we review the utility of PCCT in transcatheter SHD interventions.

Effect of Sinotubular Junction Size on TAVR Leaflet Thrombosis: A Fluid-Structure Interaction Analysis.

TAVR has emerged as a standard approach for treating severe aortic stenosis patients. However, it is associated with several clinical complications, including subclinical leaflet thrombosis characterized by Hypoattenuated Leaflet Thickening (HALT). A rigorous analysis of TAVR device thrombogenicity considering anatomical variations is essential for estimating this risk. Clinicians use the Sinotubular Junction (STJ) diameter for TAVR sizing, but there is a paucity of research on its influence on TAVR devices thrombogenicity. A Medtronic Evolut® TAVR device was deployed in three patient models with varying STJ diameters (26, 30, and 34mm) to evaluate its impact on post-deployment hemodynamics and thrombogenicity, employing a novel computational framework combining prosthesis deployment and fluid-structure interaction analysis. The 30mm STJ patient case exhibited the best hemodynamic performance: 5.94mmHg mean transvalvular pressure gradient (TPG), 2.64 cm2 mean geometric orifice area (GOA), and the lowest mean residence time (TR)-indicating a reduced thrombogenic risk; 26mm STJ exhibited a 10 % reduction in GOA and a 35% increase in mean TPG compared to the 30mm STJ; 34mm STJ depicted hemodynamics comparable to the 30mm STJ, but with a 6% increase in TR and elevated platelet stress accumulation. A smaller STJ size impairs adequate expansion of the TAVR stent, which may lead to suboptimal hemodynamic performance. Conversely, a larger STJ size marginally enhances the hemodynamic performance but increases the risk of TAVR leaflet thrombosis. Such analysis can aid pre-procedural planning and minimize the risk of TAVR leaflet thrombosis.

Deformation of transcatheter heart valves with mitral valve-in-valve.

The use of oversizing in mitral valve-in-valve (MViV) procedures can lead to non-uniform expansion of transcatheter heart valves (THV). This may have implications for THV durability. The objective of this study was to assess the extent and predictors of THV deformation in MViV procedures. We examined 33 patients who underwent MViV with SAPIEN prostheses. The extent of THV deformation (deformation index, eccentricity, neosinus volume, asymmetric leaflet expansion and vertical deformation) and hypoattenuating leaflet thickening (HALT) were assessed using cardiac computed tomography (CT), performed prospectively at 30 days post-procedure. For descriptive purposes, the THV deformation index was calculated, with values >1.00 representing a more hourglass shape. Non-uniform underexpansion of THV was common after MViV implantation, with a median expansion area of 74.0% (interquartile range 68.1-84.1) at the narrowest level and a THV deformation index of 1.21 (1.13-1.29), but circularity was maintained with eccentricity ranging from 0.24 to 0.28. The degree of oversizing was a key factor associated with greater underexpansion and a higher deformation index (β=-0.634; p<0.001; β=0.594; p<0.001, respectively). Overall, the incidence of HALT on the 30-day postprocedural CT was 27.3% (9 of 33). Most patients (32 of 33) were on anticoagulation therapy, but the prothrombin time and international normalised ratio (PT-INR) at the time of the CT scan was <2.5 in 23 of 32 patients. Among patients with a PT-INR of <2.5, HALT was predominantly observed with a high THV deformation index of ≥1.18. THV deformation, i.e., underexpansion and an hourglass shape, commonly occurs after MViV implantation and is negatively affected by excessive oversizing. Optimising THV expansion during MViV could potentially prevent HALT.

Leaflet thrombosis in transcatheter aortic valve intervention: mechanisms, prevention, and treatment options.

Transcatheter aortic valve intervention (TAVR) has emerged as a promising alternative to surgical aortic valve replacement for patients with severe aortic stenosis. However, leaflet thrombosis has raised concerns about the long-term durability and outcomes of TAVR. This study aims to provide an overview of the mechanisms, prevention strategies, and treatment options for leaflet thrombosis in TAVR. Leaflet thrombosis refers to the formation of blood clots on bioprosthetic valve leaflets, leading to impaired leaflet mobility, early valve degeneration and dysfunction, and potential clinical implications. While the mechanisms underlying thrombus formation on valve leaflets are not fully understood, several factors, such as altered blood flow patterns within valve neosinuses, prothrombotic surfaces, and patient-related causes, have been implicated. Two distinct entities have been identified, namely, hypoattenuated leaflet thickening and restricted leaflet motion. Their occurrence appears dynamic over time and is related to the valve type. Imaging, including transesophageal echocardiography and multidetector computed tomography, plays a crucial role in the diagnosis and follow-up of leaflet thrombosis. Preventing leaflet thrombosis requires a comprehensive and tailored approach involving identifying high-risk patients, close monitoring, and antithrombotic therapy. Antithrombotic therapy with dual antiplatelet agents or anticoagulation is commonly employed in TAVR patients, although the optimal regimen is yet to be defined. Novel antithrombotic agents, such as direct oral anticoagulants, are being investigated for their efficacy and safety in preventing leaflet thrombosis. When leaflet thrombosis is detected, treatment options include intensified antithrombotic therapy, valve-in-valve intervention, or balloon valvuloplasty. The long-term outcomes and impact of leaflet thrombosis on valve durability and patient prognosis are areas of ongoing research. Leaflet thrombosis in TAVR is a considerable complication affecting valve function and patient outcomes. Understanding the mechanisms underlying thrombus formation and implementing appropriate prevention strategies are essential for mitigating this risk. Treatment options aim to restore leaflet mobility and optimize valve performance. Further research is needed to establish standardized protocols for antithrombotic therapy, identify high-risk patient populations, and determine the long-term consequences of leaflet thrombosis on TAVR outcomes.

TCT-82 Implications of Prosthetic Deformation in Acute Valve-in-Valve TAVR: Hypoattenuating Leaflet Thickening at 1 Year

TCT-82 Implications of Prosthetic Deformation in Acute Valve-in-Valve TAVR: Hypoattenuating Leaflet Thickening at 1 Year

An investigator-sponsored pragmatic randomized controlled trial of AntiCoagulation vs AcetylSalicylic Acid after Transcatheter Aortic Valve Implantation: Rationale and design of ACASA-TAVI

The optimal antithrombotic therapy after transcatheter aortic valve implantation (TAVI) is unknown. Bioprosthetic valve dysfunction (BVD) is associated with adverse outcomes and may be prevented by anticoagulation therapy. A dedicated randomized trial comparing monotherapy NOAC to single antiplatelet therapy has not been performed previously. We hypothesize that therapy with any anti-factor Xa NOAC will reduce BVD compared to antiplatelet therapy, without compromising safety. ACASA-TAVI is a multicenter, prospective, randomized, open-label, blinded endpoint, all-comers trial comparing a monotherapy anti-factor Xa NOAC strategy (intervention arm) with a single antiplatelet therapy strategy (control arm) after successful TAVI. Three-hundred and sixty patients without indication for oral anticoagulation will be randomized in a 1:1 ratio to either apixaban 5 mg twice per day, edoxaban 60 mg daily, or rivaroxaban 20 mg daily for 12 months followed by acetylsalicylic acid 75 mg daily indefinitely, or to acetylsalicylic acid 75 mg daily indefinitely. The 2 co-primary outcomes are (1) incidence of Hypo-Attenuated Leaflet Thickening (HALT) on 4-dimensional cardiac CT at 12 months, and (2) a Safety Composite of VARC-3 bleeding events, thromboembolic events (myocardial infarction and stroke), and death from any cause, at 12 months. The first 100 patients had a mean age of 74 ± 3.6 years, 33% were female, the average body-mass index was 27.9 ± 4.4 kg/m2, and 15% were smokers. A balloon-expanded valve was used in 82% and a self-expandable valve in 18%. The trial is planned, initiated, funded, and conducted without industry involvement. ClinicalTrials.gov Identifier NCT05035277.

Impact of leaflet thrombosis on valve haemodynamic status after transcatheter aortic valve replacement

ObjectivesThe effect of subclinical leaflet thrombosis, characterised by hypoattenuated leaflet thickening (HALT), on the valve haemodynamic function and durability of the bioprosthetic valve, is not yet determined. We determined the...

Assessment of Hypoattenuated Leaflet Thickening Following Transcatheter Aortic Valve Replacement With the Self-Expanding Evolut Valve

Assessment of Hypoattenuated Leaflet Thickening Following Transcatheter Aortic Valve Replacement With the Self-Expanding Evolut Valve

Investigation of factors determining haemodynamic relevance of leaflet thrombosis after transcatheter aortic valve implantation.

To determine the conditions under which early hypoattenuated leaflet thickening (HALT) after transcatheter aortic valve implantation (TAVI) becomes haemodynamically relevant. The study included 100 patients (age: 81.5 ± 5.5 years; female 63%), thereof 50 patients with HALT. After anonymization and randomization, blinded readers measured maximum thrombus thickness per prosthesis (MT_pr) and movement restriction (MR_pr) on electrocardiogram (ECG)-gated whole heart cycle computed tomography angiography. These measurements were compared with echocardiographic mean pressure gradient (mPG), its increase from baseline (ΔmPG), and Doppler velocity index (DVI). Haemodynamic valve deterioration (HVD) was defined as mPG > 20 mmHg. Age, body mass index, valve type, valve size, left ventricular ejection fraction, and atrial fibrillation were considered as influencing factors. Multiple regression analysis revealed that only valve size (P = 0.001) and MT_pr (P = 0.02) had a significant influence on mPG. In an interaction model, valve size moderated the effect of MT_pr on mPG significantly (P = 0.004). Sub-group analysis stratified by valve sizes showed a strong correlation between MT_pr and echocardiographic parameters for 23 mm valves (mPG: r = 0.57, ΔmPG: r = 0.68, DVI: r = 0.55, each with P < 0.001), but neither for 26 nor 29 mm valves (r < 0.2, P > 0.2 for all correlations). Six of seven prostheses with HVD had a 23 mm valve diameter, while one had 29 mm (P = 0.02). Early HALT rarely causes significant mPG increase. Our study shows that valve size is a key factor influencing the haemodynamic impact of HALT. In small valve sizes, mPG is more likely to increase. Our study is the first to offer in vivo evidence supporting previous in vitro findings on this topic.

Hypoattenuated Leaflet Thickening After Implantation of the ACURATE neo or the ACURATE neo2 Transcatheter Heart Valve

Subclinical leaflet thrombosis, identified as hypoattenuated leaflet thickening (HALT) on cardiac computed tomography scan, has been observed after transcatheter aortic valve replacement (TAVR). However, data on HALT after the implant of the supra-annular ACURATE neo/neo2 prosthesis are limited. This study aimed to determine the prevalence and risk factors for the development of HALT after TAVR with the ACURATE neo/neo2. A total of 50 patients who received the ACURATE neo/neo2 prosthesis were prospectively enrolled. Patients underwent a contrast-enhanced multidetector row cardiac computed tomography scan at before, after, and 6months after TAVR. At the 6-month follow-up, HALT was detected in 16% (8 of 50 patients). These patients had a lower implant depth of the transcatheter heart valve (8 ± 2mm vs 5 ± 2mm, p=0.001), less calcified native valve leaflets, a better expansion of the frame at the level of the left ventricular outflow tract, and were less often hypertensive. Thrombosis of the sinus of Valsalva occurred in 18% (9/50). There was no difference in the anticoagulation regimen between patients with and without thrombotic findings. In conclusion, HALT was present in 16% of patients at 6months follow-up, patients presenting with HALT had a lower implant depth of the transcatheter heart valve, and HALT was detected in patients on oral anticoagulation therapy.

Intravenous thrombolysis for bioprosthetic valve thrombosis.

A 77-year-old woman experienced new-onset dyspnoea on exertion 1 year after alcohol septal ablation and transcatheter aortic valve implantation (TAVI) with a balloon-expandable valve for symptomatic severe aortic stenosis and basal septal hypertrophy. Transthoracic echocardiographic assessment (TTE) revealed an incremental transvalvular peak velocity from 2.9 m/s 3 days after TAVI to 4.3 m/s. Multislice computed tomography (MSCT) demonstrated hypoattenuated leaflet thickening (HALT) of all leaflets and reduced leaflet motion (RLM) of one leaflet (Panel A). Her antithrombotic regimen was changed from apixaban 5 mg bi-daily to acenocoumarol with a target international normalized ratio (INR) of 2.5–3.5. Six weeks later, symptoms persisted and the transvalvular peak velocity was 3.9 m/s (Panel B). A decision was made to attempt to resolve the thrombus with repeated intravenous infusions of alteplase.1,2 Four sequential infusions of 25 mg alteplase/25 h resulted in an uneventful but stepwise decrease of the transvalvular peak velocity to 2.8 m/s (Panel C–F). Multislice computed tomography confirmed normalization of leaflet motion with some residual remaining leaflet thickening (Panel F). MSCT cine images before and after alteplase infusion are available in the Supplementary data online (Videos S1 and S2).

Role of Multimodality Imaging in Transcatheter Structural Interventions.

Cardiac imaging is the backbone for safe and optimal transcatheter structural interventions. Transthoracic echocardiogram is the initial modality to assess valvular disorders, while transesophageal echocardiogram is best to delineate the mechanism of valvular regurgitation, preprocedural assessment for transcatheter edge-to-edge repair, and for intraprocedural guidance. Cardiac computed tomography is the modality of choice for assessing calcifications, maneuvering multiplaner reconstruction of different cardiac structures, preprocedural planning for various transcatheter valve replacement, and assessing for hypoattenuated leaflet thickening and reduced leaflet motion. Cardiac magnetic resonance imaging is best known for most accurate volumetric assessment of valvular regurgitation and chamber size quantification. Cardiac positron emission tomography is the only modality that could assess active infection through using fluorine 18 fluorodeoxyglucose radiotracer.

Clinical outcomes of the ACURATEneo2transcatheter heart valve: a prospective, multicenter, observational, post-market surveillance study.

The next-generation ACURATE neo2 transcatheter aortic valve was designed for simplified implantation and to mitigate the risk of paravalvular leak (PVL) compared to the earlier device. To collect clinical outcomes and device performance data, including echocardiography and 4-dimensional computed tomography (4D-CT) data, with the ACURATE neo2 transcatheter heart valve in patients with severe aortic stenosis (AS). ACURATE neo2 PMCF is a single-arm, multicentre study of patients with severe AS treated in routine clinical practice. The primary safety endpoint was all-cause mortality at 30-days. The primary imaging endpoint was hypo-attenuated leaflet thickening (HALT), measured by core laboratory-adjudicated 4D-CT at 30 days. Secondary endpoints included VARC safety endpoints, procedural success, and evaluation of valve performance via core laboratory-adjudicated echocardiography. The study enrolled 250 patients at 18 European centres (mean age: 80.8 years; 63.6% female; mean STS score: 2.9±2.0%); 246 (98.4%) were successfully treated with ACURATE neo2. The 30-day rates for mortality and disabling stroke were 0.8% and 0%, respectively. The new permanent pacemaker implantation rate was 6.5%. HALT >50% was present in 9.3% of patients at 30 days. Valve haemodynamics improved from baseline to 30 days (mean aortic valve gradient: from 47.6±14.5 mmHg to 8.6±3.9 mmHg; mean aortic valve area: from 0.7±0.2 cm2 to 1.6±0.4 cm2). At 30 days, PVL was evaluated as none/trace in 79.2% of patients, mild in 18.9%, moderate in 1.9%, and severe in 0%. The study results support the safety and efficacy of TAVI with ACURATE neo2 in patients in routine clinical practice.

Commissural misalignment independently predicts leaflet thrombosis after transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) has become a minimally invasive alternative to surgical aortic valve replacement. Hypo-attenuated leaflet thickening (HALT)-a marker of subclinical leaflet thrombosis commonly detected by cardiac computed tomography (CT) after TAVI-may influence valve durability and function. The purpose of this study was to compare commissural alignment of the native and prosthetic aortic valves in cardiac CT in subjects with and without HALT and thereby identify commissural misalignment as potential predictor for leaflet thrombosis after TAVI. In 170 subjects, 85 with and 85 without HALT in post-TAVI CT, commissural orientation of the prosthesis was determined comparing native and prosthetic aortic valve orientation in cardiac CT by measuring the commissural angle relative to the right coronary ostium in the aortic valve plane. For the prosthetic valve, any deviation ≤ 15° compared to the native valve was classified as "aligned"; 16-30° as "mild", 31-45° as "moderate" and ≥ 45° as "severe" misalignment. Among subjects with HALT, median angular deviation was higher (36°, IQR 31°) than in the control group (29°, IQR 29°, p = 0.042). "Severe" misalignment was more frequent in subjects who developed HALT (n = 31, 37%) compared to the control group (n = 17, 20%, p = 0.013). In logistic regression analysis, more severe deviation (p = 0.015, OR = 1.02 per 1° deviation) and "severe" misalignment (p = 0.018, OR = 2.2) represented independent predictors for the occurrence of HALT after TAVI. Subclinical leaflet thrombosis after TAVI is associated with commissural misalignment. Potential clinical advantages of obtaining commissural alignment remain to be systematically assessed.

Cardiovascular computed tomography in the evaluation of post-TAVI prosthesis dysfunction: the thin line between hypo attenuated leaflet thickening and clinical valve thrombosis.

It is accepted that hypo attenuated leaflet thickening (HALT) can be detected in 12% and 32% of transcatheter aortic valve implantation (TAVI) patients on oral anticoagulation or dual antiplatelet therapy at 3 months, respectively.1 Clinically relevant TAVI thrombosis is rare, with up to 1% incidence.2 We present the case of an 86-year-old male with a history of ischemic cardiomyopathy, atrial fibrillation (on apixaban 5 mg BID), and 4 months post-TAVI (Sapien 3–29 mm) who presented to the Emergency Department with worsening dyspnea and elevated cardiac biomarkers: HS-Tn (1689 ng/L) and NT-proBNP (>5000 pg/mL). Echocardiogram showed new severe systolic dysfunction (left ventricular EF = 30%) and elevated gradients (compared to the basal post-TAVI study) with limited visualization of the valve (central figure, Panels A and B). He underwent invasive coronary angiography, which showed no coronary artery disease progression as to explain the clinical changes. Given the rapidly worsening clinical status, a cardiovascular computed tomography (CCT) was ordered over transesophageal echocardiogram for better evaluation. The CCT was acquired using retrospective gating without ECG dose modulation (IQon, Philips) for high-quality full-cycle images (Panels C–F). There was severe symmetrical tri-leaflet thickening with sparing of the distal tips (meniscal shape), classically described in HALT.3 The Hounsfield units were more consistent with thrombus (<100 HU) (Panel C), and significantly reduced tri-leaflet motion was also noted on functional images (see Supplementary data online, Video S1). Despite being treated with i.v. heparin and guideline-directed medical therapy for HFrEF, the patient developed refractory cardiogenic shock and expired. The best antithrombotic regimen for patients undergoing TAVI remains controversial.4 Bioprosthetic valve thrombosis involves a spectrum with different grades of clinical manifestation. The CCT is paramount for establishing the etiology of the dysfunction and providing prognostic information for patient management.5