Clinical outcomes of a balloon-expandable stent for symptomatic obstructions of the subclavian or innominate arteries.

Background: Upper-extremity peripheral arterial disease (PAD) may present with a broad spectrum of signs and symptoms. If an endovascular treatment is planned, percutaneous angioplasty and stent placement may lead to a better patency compared to percutaneous angioplasty alone. We assessed the characteristics and clinical course of patients with upper-extremity PAD who received angioplasty and a balloon-expandable stent. Patients and methods: We analyzed data from consecutive patients treated with angioplasty and placement of a balloon-expandable BeSmooth Peripheral Stent System® (Bentley, Germany) at the Angiology Department (University Hospital Zurich) between 2018 and 2022. The primary outcome was re-intervention at the target lesion within 6 months from index angioplasty and during available follow-up. The study was approved by the local ethical commission. Results: A total of 27 patients were treated. The median age was 70 (Q1-Q3: 60-74) years and 59% were men. The subclavian artery (74%) represented the most frequently treated target lesion, followed by the innominate artery (26%). The mean improvement in blood pressure in the treated arm was 21 (95%CI 7 to 35) mmHg at 24 hours and 29 (95%CI 15 to 43) mmHg at 6 months. At 6 months, 2 (8%) patients required a target lesion re-intervention. During the remaining follow-up period up to 24 months, one of these two patients required additional intervention and a total of 3 (11%) patients died due to sepsis, cancer, and unknown causes, respectively. Conclusions: Percutaneous catheter-based treatment with a balloon-expandable stent for symptomatic upper extremity PAD appeared to be effective and safe.

Antibody-mediated PCSK9 neutralization worsens outcome after bare-metal stent implantation in mice.

AIMS: Despite advances in pharmacotherapy and device innovation, in-stent restenosis (ISR) and stent thrombosis (ST) remain serious complications following percutaneous coronary intervention (PCI) procedure with stent implantation. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme involved in plasma cholesterol homeostasis and recently emerged as a therapeutic target for hypercholesterolemia. Antibody-based PCSK9 inhibition is increasingly used in different subsets of patients, including those undergoing PCI. However, whether PCSK9 inhibition affects outcome after stent implantation remains unknown. METHODS AND RESULTS: 12 to 14 weeks old C57Bl/6 mice underwent carotid artery bare-metal stent implantation. Compared to sham intervention, stent implantation was associated with increased expression of several inflammatory mediators, including PCSK9. The increase in PCSK9 protein expression was confirmed in the stented vascular tissue, but not in plasma. To inhibit PCSK9, alirocumab was administered weekly to mice before stent implantation. After 6 weeks, histological examination revealed increased intimal hyperplasia in the stented segment of alirocumab-treated animals compared to controls. In vitro, alirocumab promoted migration and inhibited the onset of senescence in primary human vascular smooth muscle cells (VSMC). Conversely, it blunted the migration and increased the senescence of endothelial cells (EC). CONCLUSION: Antibody-based PCSK9 inhibition promotes in-stent intimal hyperplasia and blunts vascular healing by increasing VSMC migration, while reducing that of EC. This effect is likely mediated, at least in part, by a differential effect on VSMC and EC senescence. The herein-reported data warrant additional investigations concerning the use of PCSK9 inhibitors in patients undergoing PCI with stent implantation.

Clinical outcomes of ultrasound-assisted coagulation monitoring-adjusted catheter-directed thrombolysis for acute pulmonary embolism.

BACKGROUND: Ultrasound-assisted catheter-directed thrombolysis (USAT) may reverse right ventricular dysfunction due to acute pulmonary embolism (PE) with a favorable safety profile. METHODS: We studied intermediate-high- and high-risk acute PE patients who underwent USAT at the University Hospital Zurich, 2018-2022. The USAT regimen included alteplase 10 mg per catheter over 15 h, therapeutic-dosed heparin, and dosage adaptations based on routinely monitored coagulation parameters, notably anti-factor Xa activity and fibrinogen. We focused on the mean pulmonary arterial pressure (mPAP) and the National Early Warning Score (NEWS) before and after USAT, and reported the incidence of hemodynamic decompensation, PE recurrence, major bleeding, and death over 30 days. RESULTS: We included 161 patients: 96 (59.6 %) were men and the mean age was 67.8 (SD 14.6) years. Mean PAP decreased from a mean of 35.6 (SD 9.8) to 25.6 (SD 8.2) mmHg, whereas the NEWS decreased from a median of 5 (Q1-Q3 4-6) to 3 (Q1-Q3 2-4) points. No cases of hemodynamic decompensation occurred. One (0.6 %) patient had an episode of recurrent PE. Two (1.2 %) major bleeding events occurred, including one (0.6 %) intracranial, fatal hemorrhage in a patient with high-risk PE, severe heparin overdosing, and a recent head trauma (with negative CT scan of the brain performed at baseline). No other deaths occurred. CONCLUSIONS: USAT resulted in a rapid improvement of hemodynamic parameters among patients with intermediate-high risk acute PE and selected ones with high-risk acute PE, without any recorded deaths related to PE itself. A strategy including USAT, therapeutic-dosed heparin, and routinely monitored coagulation parameters may partly explain the overall very low rate of major bleeding.

Percutaneous large-bore aspiration embolectomy with veno-arterial extracorporal membrane oxygenation support or standby in patients with high-risk pulmonary embolism and contraindications to thrombolysis: a preliminary single centre experience.

AIMS: Large-bore catheter aspiration embolectomy reduces thrombus burden and right ventricle strain and improves haemodynamics after pulmonary embolism (PE). Sparse data are available for patients with high-risk PE and contraindications to thrombolysis or thrombolysis failure, particularly if veno-arterial extracorporal membrane oxygenation (VA-ECMO) is required. METHODS AND RESULTS: All patients with acute high-risk PE and contraindications to thrombolysis undergoing FlowTriever® percutaneous embolectomy and VA-ECMO circulatory support (or standby) at the University Hospital Zurich between April 2021 and August 2022 were retrospectively analysed. The primary outcome was the combination of recurrent PE, heart failure hospitalization, and all-cause death at 30 days. The analysis included 15 patients: mean age was 63.1 years and 14 (93%) were men. Overall, four (27%) patients presented with cardiac arrest, eight (53%) with ongoing obstructive shock, and three (20%) with persistent arterial hypotension. Veno-arterial extracorporal membrane oxygenation was implanted prior to aspiration embolectomy in eight (53%) patients. Three of seven patients without initial VA-ECMO support experienced periprocedural cardiac arrest, of whom two received ECMO support before completion of embolectomy. Veno-arterial extracorporal membrane oxygenation weaning was successful in all patients after a mean of 5.4 days. There was one periprocedural death in a patient who did not receive VA-ECMO support following a periprocedural cardiac arrest. The primary outcome at 30 days occurred in five (33.3%; 95% confidence interval 13.0-61.3%) patients. CONCLUSION: This study provides preliminary evidence for the feasibility of percutaneous large-bore aspiration embolectomy in combination with VA-ECMO support (or standby) in patients with high-risk PE and contraindications to thrombolysis.

[Update on Pulmonary Embolism: Guideline-Based Diagnosis and Therapy of an Exemplary Case]. / Update zum Thema Lungenembolie: leitliniengerechte Diagnostik und Therapie anhand eines Fallbeispiels.

Update on Pulmonary Embolism: Guideline-Based Diagnosis and Therapy of an Exemplary Case Abstract. In the evaluation of acute pulmonary embolism, a swift and focused diagnostic process is crucial and has an impact on prognosis. An initial clinical assessment is done in haemodynamically stable patients, followed by determination of D-dimer or immediate imaging by computer tomography if the clinical (pre-test) probability is high. After confirming the diagnosis of pulmonary embolism, the most appropriate anticoagulant regiment should be selected and patients should be candidate for a structured follow-up plan. The initial anticoagulant therapy regime is determined by a number of factors, including haemodynamic stability (or potential need for reperfusion treatments), demographic characteristics and comorbidities. While anticoagulation is usually recommended for the first 3-6 months, re-evaluation of therapy after acute therapy is mandatory. In addition, the possibility of chronic thrombo-embolic pulmonary hypertension (CTEPH) or a post-PE syndrome should be considered if symptoms persist after 3-6 months.

[The Role of Percutaneous Coronary Revascularization in Chronic Coronary Syndromes]. / Perkutane koronare Revaskularisation beim chronischen Koronarsyndrom: wann sinnvoll, wann nicht?

The Role of Percutaneous Coronary Revascularization in Chronic Coronary Syndromes Abstract. Coronary heart disease represents the leading cause of morbidity and mortality worldwide. Optimal management of these patients is therefore crucial and includes lifestyle changes, optimal medical therapy, and coronary revascularization. This review summarizes diagnostic and therapeutic strategies of patients with chronic coronary syndromes, focusing on the 2019 European Society of Cardiology (ESC) guidelines for the diagnosis and management of chronic coronary syndromes. In particular, the role of invasive assessment and coronary revascularization in chronic coronary syndromes is discussed.

Multimodality imaging derived energy loss index and outcome after transcatheter aortic valve replacement.

AIMS: To assess whether the combination of transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) data affects the grading of aortic stenosis (AS) severity under consideration of the energy loss index (ELI) in patients undergoing transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS: Multimodality imaging was performed in 197 patients with symptomatic severe AS undergoing TAVR at the University Hospital Zurich, Switzerland. Fusion aortic valve area index (fusion AVAi) assessed by integrating MDCT derived planimetric left ventricular outflow tract area into the continuity equation was significantly larger as compared to conventional AVAi (0.41 ± 0.1 vs. 0.51 ± 0.1 cm2/m2; P < 0.01). A total of 62 patients (31.4%) were reclassified from severe to moderate AS with fusion AVAi being >0.6 cm2/m2. ELI was obtained for conventional AVAi and fusion AVAi based on sinotubular junction area determined by TTE (ELILTL 0.47 ± 0.1 cm2/m2; fusion ELILTL 0.60 ± 0.1 cm2/m2) and MDCT (ELIMDCT 0.48 ± 0.1 cm2/m2; fusion ELIMDCT 0.61 ± 0.05 cm2/m2). When ELI was calculated with fusion AVAi the effective orifice area was >0.6 cm2/m2 in 85 patients (43.1%). Survival rate 3 years after TAVR was higher in patients reclassified to moderate AS according to multimodality imaging derived ELI (78.8% vs. 67%; P = 0.01). CONCLUSION: Multimodality imaging derived ELI reclassifies AS severity in 43% undergoing TAVR and predicts mid-term outcome.

Interleukin-1ß Mediates Arterial Thrombus Formation via NET-Associated Tissue Factor.

CANTOS reported reduced secondary atherothrombotic events in patients with residual inflammatory risk treated with the inhibitory anti-IL-1ß antibody, Canakinumab. Yet, mechanisms that underlie this benefit remain elusive. Recent work has implicated formation of neutrophil extracellular traps (NETosis) in arterial thrombosis. Hence, the present study explored the potential link between IL-1ß, NETs, and tissue factor (TF)-the key trigger of the coagulation cascade-in atherothrombosis. To this end, ST-elevation myocardial infarction (STEMI) patients from the Swiss multicenter trial SPUM-ACS were retrospectively and randomly selected based on their CRP levels. In particular, 33 patients with STEMI and high C-reactive protein (CRP) levels (≥ 10 mg/L) and, 33 with STEMI and low CRP levels (≤ 4 mg/L) were investigated. High CRP patients displayed elevated circulating IL-1ß, NETosis, and NET-associated TF plasma levels compared with low CRP ones. Additionally, analysis of patients stratified by circulating IL-1ß levels yielded similar results. Moreover, NETosis and NET-associated TF plasma levels correlated positively in the whole population. In addition to the above, translational research experiments provided mechanistic confirmation for the clinical data identifying IL-1ß as the initial trigger for the release of the pro-coagulant, NET-associated TF. In conclusion, blunted TF presentation by activated neutrophils undergoing NETosis may provide a mechanistic explanation to reduced secondary atherothrombotic events as observed in canakinumab-treated patients in CANTOS.

Incidence, predictors and cerebrovascular consequences of leaflet thrombosis after transcatheter aortic valve implantation: a systematic review and meta-analysis.

OBJECTIVES: We examined the incidence, the impact of subsequent cerebrovascular events and the clinical or procedural predictors of leaflet thrombosis (LT) in patients undergoing transcatheter aortic valve implantation (TAVI). METHODS: MEDLINE/PubMed was systematically screened for studies reporting on LT in TAVI patients. Incidence [both clinical and subclinical, i.e. detected with computed tomography (CT)] of LT was the primary end point of the study. Predictors of LT evaluated at multivariable analysis and impact of LT on stroke were the secondary ones. RESULTS: Eighteen studies encompassing 11 124 patients evaluating incidence of LT were included. Pooled incidence of LT was 0.43% per month [5.16% per year, 95% confidence interval (CI) 0.21-0.72, I2 = 98%]. Pooled incidence of subclinical LT was 1.36% per month (16.32% per year, 95% CI 0.71-2.19, I2 = 94%). Clinical LT was less frequent (0.04% per month, 0.48% per year, 95% CI 0.00-0.19, I2 = 93%). LT increased the risk of stroke [odds ratio (OR) 4.21, 95% CI 1.27-13.98], and was more frequent in patients with a valve diameter of 28-mm (OR 2.89: 1.55-5.8), for balloon-expandable (OR 8: 2.1-9.7) or after valve-in-valve procedures (OR 17.1: 3.1-84.9). Oral anticoagulation therapy reduced the risk of LT (OR 0.43, 95% CI: 0.22-0.84, I2 = 64%), as well as the mean transvalvular gradient. CONCLUSIONS: LT represents an infrequent event after TAVI, despite increasing risk of stroke. Given its full reversal with warfarin, in high-risk patients (those with valve-in-valve procedures, balloon expandable or large-sized devices), a protocol which includes a control CT appears reasonable.

[Therapeutic Strategies in Patients with Stable Coronary Artery Disease: The Role of Coronary Revascularization]. / Moderne Therapie der stabilen koronaren Herzkrankheit: Der Stellenwert der koronaren Revaskularisation.

Therapeutic Strategies in Patients with Stable Coronary Artery Disease: The Role of Coronary Revascularization Abstract. Coronary artery disease is the leading cause of death worldwide. Prevention and optimal treatment of patients with coronary artery disease is therefore crucial. Lifestyle changes, optimal medical therapy and aggressive risk factor control represent key elements in the management of patients with stable coronary artery disease. Coronary revascularization of flow-limiting coronary artery stenoses is indicated to reduce myocardial ischemia and related symptoms. This review summarizes treatment strategies of patients with stable coronary artery disease, focusing on the 2018 European Society of Cardiology (ESC) guidelines of myocardial revascularization.

Long-term durability and haemodynamic performance of a self-expanding transcatheter heart valve beyond five years after implantation: a prospective observational study applying the standardised definitions of structural deterioration and valve failure.

AIMS: Long-term results of transcatheter aortic valve implantation (TAVI), in particular the incidence of bioprosthetic valve failure (BVF), are uncertain. This study presents data derived from a long-term, structured follow-up programme of the self-expanding CoreValve device utilising standardised definitions and core lab adjudication of valve performance. METHODS AND RESULTS: The study prospectively included all 152 patients who had undergone TAVI with the self-expanding CoreValve up to December 2011 at the Heart Center, Bad Segeberg, Germany. Late BVF (>30 days) was defined as either: 1) severe structural valve deterioration (transprosthetic mean pressure gradient ≥40 mmHg and/or ≥20 mmHg rise from baseline OR severe intraprosthetic aortic regurgitation), OR 2) bioprosthetic valve dysfunction leading to death or reintervention. Echocardiographic follow-up at 6.3±1.0 years (range: 5.0-8.9 years) was 88% complete (60 out of 68 survivors beyond five years) and all echocardiograms were analysed by an independent core laboratory. The all-cause mortality rate at 1, 2, 5, 6, 7 and 8 years was 14%, 20%, 50%, 60%, 65%, and 73%, respectively. Among survivors beyond five years, effective orifice area was 1.60±0.46 cm2, and transvalvular mean pressure gradient was 6.7±3.1 mmHg; no cases showed evidence of structural valve deterioration. Five patients (3.3%) had undergone redo TAVI (n=4) or surgery (n=1) 0.6 to 5.2 years after the index procedure, all due to paravalvular leakage. The estimated rate of BVF at eight years was 7.9% for the actuarial and 4.5% for the actual analysis. CONCLUSIONS: Long-term follow-up up to 8.9 years after TAVI documents favourable performance of the self-expanding CoreValve with low rates of BVF.

A Novel Angiographic Quantification of Aortic Regurgitation After TAVR Provides an Accurate Estimation of Regurgitation Fraction Derived From Cardiac Magnetic Resonance Imaging.

OBJECTIVES: This study sought to compare a new quantitative angiographic technique to cardiac magnetic resonance-derived regurgitation fraction (CMR-RF) for the quantification of prosthetic valve regurgitation (PVR) after transcatheter aortic valve replacement (TAVR). BACKGROUND: PVR after TAVR is challenging to quantify, especially during the procedure. METHODS: Post-replacement aortograms in 135 TAVR recipients were analyzed offline by videodensitometry to measure the ratio of the time-resolved contrast density in the left ventricular outflow tract to that in the aortic root (videodensitometric aortic regurgitation [VD-AR]). CMR was performed within an interval of ≤30 days (11 ± 6 days) after the procedure. RESULTS: The average CMR-RF was 6.7 ± 7.0% whereas the average VD-AR was 7.0 ± 7.0%. The correlation between VD-AR and CMR-RF was substantial (r = 0.78, p < 0.001). On receiver-operating characteristic curves, a VD-AR ≥10% corresponded to >mild PVR as defined by CMR-RF (area under the curve: 0.94; p < 0.001; sensitivity 100%, specificity 83%), whereas a VD-AR ≥25% corresponded to moderate-to-severe PVR (area under the curve: 0.99; p = 0.004; sensitivity 100%, specificity 98%). Intraobserver reproducibility was excellent for both techniques (for CMR-RF, intraclass correlation coefficient: 0.91, p < 0.001; for VD-AR intraclass correlation coefficient: 0.93, p < 0.001). The difference on rerating was -0.04 ± 7.9% for CMR-RF and -0.40 ± 6.8% for VD-AR. CONCLUSIONS: The angiographic VD-AR provides a surrogate assessment of PVR severity after TAVR that correlates well with the CMR-RF.

Long-Term Clinical Outcome of Early Generation Versus New-Generation Drug-Eluting Stents in 481 Patients Undergoing Rotational Atherectomy: A Retrospective Analysis.

INTRODUCTION: New-generation drug-eluting stents (NG-DES) are superior to early generation DES (EG-DES) in the majority of lesion and patient subsets, but comparative data in patients with severely calcified coronary lesions are lacking. This study aims to compare clinical outcomes of EG-DES and NG-DES in patients undergoing rotational atherectomy (RA) in calcified lesions. METHODS: Data of 268 patients (288 lesions) treated with EG-DES and 213 patients (225 lesions) receiving NG-DES after RA were retrospectively analyzed from a single-center registry. All major adverse cardiac events (MACE) were assessed at 2 years. RESULTS: Compared to the EG-DES group, patients with NG-DES more commonly had diabetes mellitus (31.9% vs. 40.9%; p = 0.04), left main lesions (7.6% vs. 17.3%; p < 0.001) and chronic total occlusions (3.5% vs. 8.5%; p = 0.016), and had a higher total stent length (30.5, IQR 20-40 mm, vs. 38, IQR 22-53 mm, p < 0.001). The Kaplan-Meier estimated rate of cardiovascular events at 2 years showed a lower incidence of death (13.5% vs. 8.2%, log-rank p = 0.13; adjusted HR after Cox regression analysis 0.49; 95% CI 0.26-0.92; p = 0.03) and a lower MACE rate (31.1% vs. 21.1%, log-rank p = 0.04; adjusted HR 0.65; 95% CI 0.42-0.98; p = 0.04) in the NG-DES group. CONCLUSIONS: Although RA is performed in more complex patients and lesions in the NG-DES era, use of NG-DES is associated with lower rates of death and MACE at 2 years as compared to EG-DES.

Impact of stroke volume assessment by integrating multi-detector computed tomography and Doppler data on the classification of aortic stenosis.

BACKGROUND: The prevalence of low flow low gradient (LFLG) severe aortic stenosis (AS) may be overrated due to underestimation of stroke volume in two-dimensional (2D) echocardiography. The implications of 3D imaging on stroke volume calculation for AS classification have not been elucidated. Integrating multi-detector computed tomography (MDCT) and Doppler data may improve diagnostic accuracy in patients with LFLG AS. METHODS: A total of 186 patients with severe AS evaluated for transcatheter aortic valve replacement were classified according to indexed stroke volume (SVI, cut-off 35mL/m2) and mean transaortic pressure gradient (cut-off 40mmHg). SVI was calculated using a) the biplane Simpson's method, b) left ventricular outflow tract (LVOT) velocity time integral (VTI) and LVOT diameter determined by 2D echocardiography, or c) LVOT VTI and LVOT area planimetered by MDCT. RESULTS: SVI assessed by the biplane Simpson's method was smaller than that obtained from 2D echocardiography LVOT diameter (29.5±0.6 vs 34.9±0.8mL/m2, p<0.001). The latter was smaller than SVI calculated by integrating MDCT and Doppler data (47.5±1.4mL/m2, p<0.001). LFLG and paradoxical LFLG severe AS were diagnosed in 42.5% and 27.4% of patients using the biplane Simpson's method, in 30.1% and 16.7% using 2D echocardiography LVOT diameter, and in 17.2% and 8.1% when integrating MDCT and Doppler data. CONCLUSIONS: The prevalence of LFLG and paradoxical LFLG severe AS was overestimated by 2.5- and 3.4-fold based on 2D echocardiography alone. Integration of MDCT and Doppler data should be considered for stroke volume assessment in the classification of severe AS.

Comparison of dual antiplatelet therapy versus oral anticoagulation following transcatheter aortic valve replacement: A retrospective single-center registry analysis.

BACKGROUND: The choice of optimal antithrombotic regimen after transcatheter aortic valve replace-ment (TAVR) remains a matter of debate. The objective of this study was to compare both efficacy and safety outcomes based on the type of antithrombotic therapy prescribed after TAVR Methods: This is a retrospective analysis of 514 consecutive patients treated with either dual antiplate¬let therapy (DAPT) (n = 315; 61.3%) or oral anticoagulation (OAC) plus clopidogrel (n = 199; 38.7%) for a minimum of 3 months after TAVR followed by antiplatelet monotherapy or OAC only, respectively. Patients had pre-defined clinical and echocardiographic follow-ups at 30 days, 6 and 12 months. The key efficacy endpoint was a composite of all-cause death, myocardial infarction, stroke and valve throm¬bosis at 1 year. The key safety endpoint was the occurrence of life-threatening/major bleeding at 1 year. RESULTS: Baseline characteristics did not differ between both groups, except for a higher incidence of atrial fibrillation in the OAC group. No significant differences in both efficacy and safety endpoints were observed at 30 days and 6 months. At 1 year, the key efficacy endpoint occurred in 21.5% of the DAPT group compared to 19.7% of the OAC group (p = 0.61). The key safety endpoint occurred in 25.1% and 27.8%, respectively (p = 0.53). However, after 1 year valve thrombosis was reported in 8 (2.5%) patients in the DAPT group but not in the OAC group (p = 0.02). CONCLUSIONS: OAC after TAVR seems to reduce the risk of clinical valve thrombosis without a statisti-cally significant increase in bleeding complications.

Clinical Bioprosthetic Heart Valve Thrombosis After Transcatheter Aortic Valve Replacement: Incidence, Characteristics, and Treatment Outcomes.

OBJECTIVES: The aim of this study was to determine the incidence, characteristics, and treatment outcomes of patients diagnosed with clinical transcatheter heart valve thrombosis. BACKGROUND: Limited data exists on clinical or manifest transcatheter heart valve thrombosis. Prior studies have focused on subclinical thrombosis. METHODS: A retrospective analysis was conducted of prospectively collected data from a single-center registry that included 642 consecutive patients who underwent transcatheter aortic valve replacement between 2007 and 2015 (305 patients had self-expanding valves; balloon-expandable, n = 281; mechanically expanding, n = 56). Long-term oral anticoagulation (OAC) was indicated in 261 patients, while 377 patients received dual-antiplatelet therapy post-procedure. All patients underwent scheduled clinical and echocardiographic follow-up. RESULTS: The overall incidence of clinical valve thrombosis was 2.8% (n = 18). No patient on OAC developed thrombosis. Of the detected thrombosis cases, 13 patients had balloon-expandable, 3 had self-expanding, and 2 had mechanically expanding valves. Thrombosis occurred significantly more often with balloon-expandable valves (odds ratio: 3.45; 95% confidence interval: 1.22 to 9.81; p = 0.01) and following valve-in-valve procedures (odds ratio: 5.93; 95% confidence interval: 2.01 to 17.51; p = 0.005). Median time to diagnosis of valve thrombosis was 181 days. The median N-terminal pro-brain natriuretic peptide level was 1,318 pg/ml (interquartile range: 606 to 1,676 pg/ml). The mean transvalvular gradient and valve area were 34 ± 14 mm Hg and 1.0 ± 0.46 cm2, respectively. Computed tomography showed hypoattenuating areas with reduced leaflet motion. Initiation of OAC resulted in significant reduction of transvalvular gradient and clinical improvement. No deaths were related to valve thrombosis. CONCLUSIONS: Clinical transcatheter heart valve thrombosis is more common than previously considered, characterized by imaging abnormalities and increased gradients and N-terminal pro-brain natriuretic peptide levels. It occurred more commonly after balloon-expandable transcatheter aortic valve replacement and valve-in-valve procedures. OAC appeared to be effective in the prevention and treatment of valve thrombosis. Randomized control trials are needed to define optimal antithrombotic therapy after transcatheter aortic valve replacement.