Lower revascularization rates after high-speed rotational atherectomy compared to modified balloons in calcified coronary lesions: 5-year outcomes of the randomized PREPARE-CALC trial.

BACKGROUND: In the PREPARE-CALC trial, severely calcified lesion preparation with rotational atherectomy (RA) before biodegradable polymer sirolimus-eluting stent (SES) implantation demonstrated higher procedural success and comparable rates of acute lumen gain and late lumen loss compared to modified balloons (MB) (scoring/cutting). We aimed to analyze the 5-year outcomes of both lesion preparation strategies. METHODS: PREPARE-CALC randomly assigned 200 patients 1:1 to MB or RA, followed by SES implantation. The principal endpoint of the current analysis was target vessel failure (TVF) at 5 years. RESULTS: At 5 years, MB had comparable rates of TVF to RA (19% vs. 21%, HR 1.14, 95% CI 0.60-2.16, p = 0.687). Subgroup analysis showed a lesion length treatment interaction, favoring MB for short lesions and RA for long ones (p for interaction = 0.042). Target lesion revascularization (TLR) was significantly less common with RA (12 vs. 3%, HR 0.28, 95% CI 0.08-0.98, p = 0.048). In a multivariate analysis, RA was independently protective against TLR (adj. HR 0.17, 95% CI 0.04-0.78, p = 0.022), while ostial lesions were associated with higher TLR independent of treatment strategy (adj. HR 11.3, 95% CI 2.98-42.6, p < 0.001). CONCLUSION: In patients with severely calcified coronary lesions, using MB or RA for lesion preparation followed by biodegradable polymer SES implantation was associated with comparable rates of TVF at 5 years. However, a significant reduction of TLR was observed after RA. PREPARE-CALC is the first randomized trial showing potential clinical advantages of RA over MB during long-term follow-up. CLINICAL TRIAL REGISTRATION: URL: https://www. CLINICALTRIALS: gov . Unique identifier: NCT02502851.

In-hospital Outcomes of Rotational Atherectomy in ST-Elevation Myocardial Infarction: Results From the Multicentre ROTA-STEMI Network.

BACKGROUND: Although the use of rotational atherectomy (RA) is off-label in the setting of ST-elevation myocardial infarction (STEMI), it can be the only option in severely calcified culprit lesions to achieve procedural success. We sought to investigate the safety and feasibility of RA during primary percutaneous coronary intervention (PPCI). METHODS: This was a retrospective observational study of patients who underwent RA during PPCI from 12 European centres. The main outcomes were procedural success (defined as successful stent implantation with final thrombolysis in myocardial infarction [TIMI] flow 3 and residual stenosis < 30%) and in-hospital mortality. A comparison of patients presenting with and without shock was performed. RESULTS: In 104 patients with RA during STEMI, the mean age was 72.8 ± 9.1 years, and 35% presented with cardiogenic shock. Bailout RA was performed in 76.9% of cases. Mean burr size was 1.42 ± 0.21 mm. Procedural success was achieved in 86.5% of cases, with no difference between shocked and nonshocked patients (94.4% vs 82.4%; P = 0.13). In-hospital stent thrombosis occurred in 0.96%, perforation in 1.9% and burr entrapment in 2.9% of cases. In spite of equally high procedural success, in-hospital mortality was higher in shocked (50%) compared with nonshocked patients (1.5%; P < 0.0001). CONCLUSIONS: Patients presenting with STEMI requiring RA, represent a high-risk population, frequently presenting with cardiogenic shock. In this analysis of selected patients, RA was performed as a bailout strategy in the majority, and, as such, RA seems to be feasible with a high procedural success rate. In the absence of cardiogenic shock, RA-facilitated PCI seems to be associated with low in-hospital mortality.

Sex-specific Inequalities in the Treatment of Severely Calcified Coronary Lesions: A Sub-analysis of the PREPARE-CALC Trial.

Background: Coronary vessels in women may have anatomical and histological particularities. The aim of this study was to investigate sex-specific characteristics and outcomes of patients with calcified coronary arteries in the Prepare-CALC (Comparison of Strategies to Prepare Severely Calcified Coronary Lesions) trial. Methods: The Prepare-CALC trial randomised patients with severe coronary calcification to coronary lesion preparation either using modified balloons (MB; cutting or scoring) or rotational atherectomy (RA). Results: Of 200 randomised patients, 24% were women. Strategy success in general was similar between women (93.8%) and men (88.2%; p=0.27). For men, strategy success was significantly more common with an RA-based strategy than an MB-based strategy (98.7% in the RA group versus 77.3% in the MB group, p<0.001), whereas for women there was no evidence of a significant difference in strategy success between RA and MB (95.7% in the RA group versus 92% in the MB group, p>0.99, p for interaction between sex and treatment strategy=0.03). Overall, significant complications such as death, MI, stent thrombosis, bypass operation and perforations were rare and did not differ significantly by gender or treatment strategy. Plaque rupture and disrupted calcified nodules were more common in women. Conclusion: In a well-defined patient population with severely calcified coronary arteries, lesion preparation with an RA-strategy was superior to an MB-strategy in men. For women, both RA and MB strategies appear to have a similar success rate, although definitive conclusions are limited due to the small number of women in the trial.

Rotational atherectomy of calcified coronary lesions: current practice and insights from two randomized trials.

With growing experience, technical improvements and use of newer generation drug-eluting stents (DES), recent data showed satisfactory acute and long-term results after rotational atherectomy (RA) in calcified coronary lesions. The randomized ROTAXUS and PREPARE-CALC trials compared RA to balloon-based strategies in two different time periods in the DES era. In this manuscript, we assessed the technical evolution in RA practice from a pooled analysis of the RA groups of both trials and established a link to further recent literature. Furthermore, we sought to summarize and analyze the available experience with RA in different patient and lesion subsets, and propose recommendations to improve RA practice. We also illustrated the combination of RA with other methods of lesion preparation. Finally, based on the available evidence, we propose a simple and practical approach to treat severely calcified lesions.

Rotational Atherectomy or Balloon-Based Techniques to Prepare Severely Calcified Coronary Lesions.

BACKGROUND: The comparative efficacy of percutaneous techniques for the preparation of calcified lesions before stenting remains poorly studied. OBJECTIVES: This study sought to compare the performance of up-front rotational atherectomy (RA) or balloon-based techniques before drug-eluting stent implantation in severely calcified coronary lesions as assessed by angiography and optical coherence tomography (OCT). METHODS: Patient-level data from the PREPARE-CALC (Comparison of Strategies to Prepare Severely Calcified Coronary Lesions) and ISAR-CALC (Comparison of Strategies to Prepare Severely Calcified Coronary Lesions) randomized trials were pooled. The primary endpoint was stent expansion as assessed by OCT imaging. The secondary endpoints included stent eccentricity, stent asymmetry, angiographic acute lumen gain, strategy success and in-hospital occurrence of cardiac death, target vessel myocardial infarction, and repeat revascularization. RESULTS: Among 274 patients originally randomized, 200 participants with available OCT data after lesion preparation with RA (n = 63), a modified balloon (MB, n = 103), or a super high-pressure balloon (n = 34) before stenting were analyzed. The use of RA versus MB or a super high-pressure balloon led to comparable stent expansion (73.2% ± 11.6% vs 70.8% ± 13.6% vs 71.8% ± 12.2%, P = 0.49) and stent asymmetry (P = 0.83). Compared with RA or MB, a super high-pressure balloon was associated with less stent eccentricity (P = 0.03) with a numerically higher acute lumen gain, albeit not significantly different (P = 0.08). Strategy success was more frequent with RA versus MB (P = 0.002) and numerically more frequent with RA versus a super high-pressure balloon (P = 0.06). Clinical outcomes did not differ between groups. CONCLUSIONS: In patients with severely calcified lesions undergoing drug-eluting stent implantation, lesion preparation with RA, MB, or a super high-pressure balloon was associated with comparable stent expansion. A super high-pressure balloon is associated with less stent eccentricity, whereas strategy success is more frequent with RA.

Angiographic predictors of unplanned rotational atherectomy in complex calcified coronary artery disease: a pooled analysis from the randomised ROTAXUS and PREPARE-CALC trials.

BACKGROUND: Calcified coronary lesions present therapeutic challenges for the interventional cardiologist, often requiring rotational atherectomy (RA). AIMS: This study aimed to develop an angiographic scoring tool to predict the need for a priori RA. METHODS: A pooled analysis of the randomised ROTAXUS and PREPARE-CALC studies was carried out, (N=220 patients, N=313 lesions), by virtue of the fact that both studies made provision for crossover to RA (from balloon dilatation or modified balloon dilatation, respectively). Logistical regression techniques were employed to assess for the presence of patient- or lesion-specific factors leading to a necessity for RA. External validation was performed though retrospective calculation of the score for 192 patients who underwent bail-out RA in a single centre. RESULTS: Lesion length (odds ratio [OR] 1.02, 95% confidence interval [CI]: 1.00-1.04 per mm, p=0.04), bifurcation lesion (OR 2.60, 95% CI: 1.27-5.30, p=0.009), vessel tortuosity >45° (OR 3.49, 95% CI: 1.73-7.03, p<0.001) and severe vessel calcification (OR 11.60, 95% CI: 3.40-39.64, p<0.001) were predictive of the need for RA in multivariate analysis. Based on the regression coefficients, a scoring system was devised. The greater the score, the more likely a lesion required RA. The scoring system performed well in the external validation cohort, with 78% of patients crossing over having a score of greater than the proposed cut-off of 3. CONCLUSIONS: We provide an angiographic scoring tool to support the expeditious use of time and resources, allowing assessment of the likelihood of success of a balloon-based strategy, or the necessity for RA.

Feasibility and safety of minimal-contrast IVUS-guided rotational atherectomy for complex calcified coronary artery disease.

OBJECTIVES: To assess the feasibility and safety of minimal-contrast percutaneous coronary intervention (PCI) using rotational atherectomy (RA) in patients with severe coronary calcification at high-risk of contrast-associated acute kidney injury (AKI). METHODS: Twenty-six patients with advanced chronic kidney disease undergoing PCI with RA at three high-volume centres were included. Baseline intravascular ultrasound (IVUS) was performed to assess lesion morphology, and to guide burr-, balloon-, and stent-selection. Final result was assessed by IVUS and angiographically. Feasibility and safety were determined by procedural and in-hospital complications, and efficacy was assessed by freedom from contrast-associated AKI after PCI. Procedural and in-hospital outcome was compared to a propensity-matched population of standard RA PCI. RESULTS: Mean glomerular filtration rate was 32 ± 17 ml/min/1.73 m2. In seven cases PCI was performed in the setting of acute coronary syndrome. The left main coronary artery was treated in 27.8% and a two-stent bifurcation technique in 44.4%. RA was more often performed electively compared to the standard RA cohort (92.3 vs. 50%; p = 0.0016). Angiographic success was achieved in 100% and documented with a median contrast amount of 12.5 ml [Range 4-43]. No in-hospital death or myocardial infarction was reported. Contrast-associated AKI occurred in one patient versus five patients in standard RA group (p = 0.19). Shorter fluoroscopy time and lower radiation dose were achieved as compared to standard RA. CONCLUSION: A minimal-contrast RA approach with IVUS-guidance for treatment of complex calcified coronary lesions is feasible and safe with high success rate.

Optical Coherence Tomography Assessment in Patients Treated With Rotational Atherectomy Versus Modified Balloons: PREPARE-CALC OCT.

[Figure: see text].

Impact of Calcified Lesion Complexity on the Success of Percutaneous Coronary Intervention With Upfront High-Speed Rotational Atherectomy or Modified Balloons - A Subgroup-Analysis From the Randomized PREPARE-CALC Trial.

BACKGROUND/PURPOSE: In the randomized PREPARE-CALC trial, lesion preparation of calcified lesions with upfront rotational atherectomy (RA) prior to drug-eluting stent (DES) implantation resulted in higher acute success as compared to a provisional modified balloon (MB) strategy. We aimed to investigate the impact of calcified lesion complexity on the treatment effect with either MB or RA. METHODS/MATERIALS: Two hundred patients were randomized to lesion preparation with either MB or RA. The study population was stratified according to lesion complexity into at least one type-C lesion or into exclusively non-type-C lesions. Endpoints were strategy success, need for bail-out RA, acute lumen gain, and late lumen loss (LLL) at 9 months. RESULTS: In total, 143 patients were graded as type-C (45% patients were allocated to MB), whereas 57 patients were graded as non-type-C (61% patients were allocated to MB). In patients with at least one type-C lesion, strategy success with RA was higher than with MB (97% vs 72%, p < 0.001), but superiority of RA was not observed in patients with non-type-C lesions (100% vs 97%, p = 1.00; pinteraction = 0.001). The need for bail-out RA was higher in patients with type-C lesions (n = 15) as compared with non-type-C lesions (n = 1). Acute lumen gain, LLL, and target lesion revascularization at 9 months were not dependent on lesion complexity and upfront lesion preparation strategy. CONCLUSIONS: In patients with calcified non-type-C lesions, the treatment strategy with RA or MB before DES implantation results in comparable success rates, whereas in type-C lesions upfront RA appears to be the superior upfront strategy.

Super high-pressure balloon versus scoring balloon to prepare severely calcified coronary lesions: the ISAR-CALC randomised trial.

BACKGROUND: The comparative efficacy of balloon-based techniques to prepare severely calcified coronary lesions before stenting remains poorly studied. AIMS: We sought to compare stent expansion following preparation of severely calcified coronary lesions with either a super high-pressure balloon or a scoring balloon. METHODS: In this randomised, open-label trial, patients with severely calcified coronary lesions were enrolled at five centres in Germany and Switzerland. After unsuccessful lesion preparation with a standard non-compliant balloon (<30% reduction of baseline diameter stenosis), participants were randomised to predilation with either a super high-pressure balloon or a scoring balloon before drug-eluting stent (DES) implantation. The primary endpoint of the study was stent expansion index as assessed by optical coherence tomography (OCT). The key secondary endpoints included angiographic, strategy and procedural success. RESULTS: OCT data after DES implantation were available for 70 out of 74 patients (94.6%) enrolled. Lesion preparation with a super high-pressure balloon versus a scoring balloon led to a comparable stent expansion index (0.72±0.12 vs 0.68±0.13; p=0.22). Compared with the scoring balloon, the super high-pressure balloon increased the minimum lumen diameter (2.83±0.34 mm vs 2.65±0.36 mm; p=0.03) and reduced the diameter stenosis (11.6±4.8% vs 14.4±5.6%; p=0.02) without difference in terms of angiographic success (100% vs 97.3%; p>0.99). Strategy success (91.9% vs 83.8%; p=0.48) and procedural success (100% vs 89.2%; p=0.12) were numerically more frequent with the super high-pressure balloon versus the scoring balloon. CONCLUSIONS: In patients with severely calcified coronary artery lesions, preparation with a super high-pressure balloon versus a scoring balloon was associated with comparable stent expansion on intravascular imaging and a trend towards improved angiographic performance. Visual summary. A ComparIson of Strategies to PrepAre SeveRely CALCified Coronary Lesions: the ISAR-CALC randomised trial.

Impact of Lesion Preparation Technique on Side Branch Compromise in Calcified Coronary Bifurcations: A Subgroup Analysis of the PREPARE-CALC Trial.

OBJECTIVES: To analyze the impact of different techniques of lesion preparation of severely calcified coronary bifurcation lesions. BACKGROUND: The impact of different techniques of lesion preparation of severely calcified coronary bifurcation lesions is poorly investigated. METHODS: We performed an as-treated analysis on 47 calcified bifurcation lesions treated with scoring/cutting balloons (SCB) and 68 lesions treated with rotational atherectomy (RA) in the PREPARE-CALC trial. Compromised side branch (SB) as assessed in the final angiogram was the primary outcome measure and was defined as any significant stenosis, dissection, or thrombolysis in myocardial infarction flow <3. RESULTS: True bifurcation lesions were present in 49% vs. 43% of cases in the SCB and RA groups, respectively. After stent implantation, SB balloon dilatation was necessary in around one-third of cases (36% vs. 38%; p = 0.82), and a two-stent technique was performed in 21.3% vs. 25% (p = 0.75). At the end of the procedure, the SB remained compromised in 15 lesions (32%) in the SCB group and 5 lesions (7%) in the RA group (p = 0.001). Large coronary dissections were more frequently observed in the SCB group (13% vs. 2%; p = 0.02). Postprocedural levels of cardiac biomarkers were significantly higher in patients with a compromised SB at the end of the procedure. CONCLUSIONS: In the PREPARE-CALC trial, side branch compromise was more frequently observed after lesion preparation with SCB as compared with RA. Consequently, in calcified bifurcation lesions, an upfront debulking with an RA-based strategy might optimize the result in the side branch.

Bioprosthetic Valve Performance After Transcatheter Aortic Valve Replacement With Self-Expanding Versus Balloon-Expandable Valves in Large Versus Small Aortic Valve Annuli: Insights From the CHOICE Trial and the CHOICE-Extend Registry.

OBJECTIVES: The aim of this study was to compare self-expanding and balloon-expandable transcatheter heart valves (THVs) in large versus small aortic valve annuli. BACKGROUND: The degree of THV oversizing varies according to annular size, and this can modify the hemodynamic performance of self-expanding and balloon-expandable THVs. METHODS: Patients undergoing transcatheter aortic valve replacement in the randomized CHOICE (Comparison of Transcatheter Heart Valves in High Risk Patients With Severe Aortic Stenosis: Medtronic CoreValve vs Edwards SAPIEN XT) trial (CoreValve [CV], n = 120; SAPIEN XT [SXT], n = 121) and the nonrandomized CHOICE-Extend registry (Evolut R [ER], n = 100; SAPIEN 3 [S3], n = 334) were compared for THV performance by echocardiography (in all patients) and by cardiac magnetic resonance imaging (MRI) regurgitant fraction (RF) (in a subgroup of patients). Patients were stratified according to aortic valve annular mean diameter into those with large (>23 mm) or small (≤23 mm) annuli. RESULTS: THV percentage oversizing was 19.1 ± 6.4% with the CV, 11.4 ± 7.0% with the SXT, 18.8 ± 4.8% with the ER, and 3.7 ± 5.5% with the S3. Transvalvular mean pressure gradient was lower with the CV and ER than with the SXT and S3 in both the large and small annulus groups. In the randomized CHOICE trial, moderate to severe prosthetic valve regurgitation (PVR) was more with the CV than the SXT in large annuli (15.1% vs. 0.0%; p = 0.002; MRI RF: 10.5 ± 10.2% vs. 4.4 ± 4.5%; p = 0.036) but not in small annuli (0.0% vs. 5.7%; p = 0.50; MRI RF: 4.0 ± 4.1% vs. 4.0 ± 3.4%; p = 0.98). In the CHOICE-Extend registry, moderate to severe PVR occurred in 2 patients, and any PVR was not significantly different between the ER and the S3 in large (41.7% vs. 32.5%; p = 0.24) or small (47.1% vs. 43.8%; p = 0.84) annuli. MRI RF was not different in large annuli (5.0 ± 3.8% vs. 5.0 ± 6.1%; p = 0.99) but was significantly lower with the ER than the S3 in small annuli (2.9 ± 2.3% vs. 4.8 ± 3.7%; p = 0.023). On multivariate analysis, transcatheter aortic valve replacement with the ER in small annuli was associated with a lower rate of prosthesis-patient mismatch than with the S3, with no increased risk for PVR. CONCLUSIONS: Older-generation balloon-expandable THVs were associated with less PVR than self-expanding THVs in patients with large but not small annuli. The next-generation self-expanding THV has improved sealing in patients with large annuli and may have potential advantages in patients with small annuli.

High-Speed Rotational Atherectomy Versus Modified Balloons Prior to Drug-Eluting Stent Implantation in Severely Calcified Coronary Lesions.

BACKGROUND: Balloon dilatation or debulking seems to be essential to allow successful stent implantation in calcified coronary lesions. Compared with standard balloon predilatation, debulking using high-speed rotational atherectomy (RA) is associated with higher initial procedural success albeit with higher in-stent late lumen loss at intermediate-term follow-up. Whether modified (scoring or cutting) balloons (MB) could achieve similar procedural success compared with RA is not known. In addition, whether new-generation drug-eluting stents could counterbalance the excessive neointimal proliferation triggered by RA remains to be determined. METHODS AND RESULTS: We randomly assigned patients with documented myocardial ischemia and severely calcified native coronary lesions undergoing percutaneous coronary intervention to a strategy of lesion preparation using MB or RA followed by drug-eluting stent implantation. Stenting was performed using a third-generation sirolimus-eluting stent with a bioabsorbable polymer. The trial had 2 primary end points: strategy success (defined as successful stent delivery and expansion with attainment of <20% in-stent residual stenosis in the presence of TIMI [Thrombolysis in Myocardial Infarction] 3 flow without crossover or stent failure; powered for superiority) and in-stent late lumen loss at 9 months (powered for noninferiority). Two hundred patients were enrolled at 2 centers in Germany (n=100 in each treatment group). The mean age of the study population was 74.9±7.0 years; 76% were men, and 33.5% had diabetes mellitus. Strategy success was significantly more common in the RA group (81% versus 98%; relative risk of failure with an MB- versus RA-based strategy, 9.5; 95% CI, 2.3-39.7; P=0.0001), but mean fluoroscopy time was longer (19.6±13.4 versus 23.9±12.2 minutes; P=0.03). At 9 months, mean in-stent late lumen loss was 0.16±0.39 mm in the MB group and 0.22±0.40 mm in the RA group ( P=0.21, P=0.02 for noninferiority). Target lesion revascularization (7% versus 2%; P=0.17), definite or probable stent thrombosis (0% versus 0%; P=1.00), and target vessel failure (8% versus 6%; P=0.78) were low and not significantly different between the MB and RA groups. CONCLUSIONS: Lesion preparation with upfront RA before drug-eluting stent implantation is feasible in nearly all patients with severely calcified coronary lesions, is more commonly successful as a primary strategy compared with MB, and is not associated with excessive late lumen loss. A strategy of provisional MB remains feasible, safe, and effective as long as bailout RA is readily available and may offer the advantages of compatibility with smaller sized catheters and less irradiation. Both strategies are associated with excellent clinical outcome at 9 months. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02502851.

The fate of incomplete scaffold apposition of everolimus-eluting bioresorble scaffolds: A serial optical coherence tomography analysis.

BACKGROUND: Incomplete stent apposition (ISA) can be divided into acute and late forms. Late ISA may be due to persistent ISA or late-acquired ISA (LAISA). This study evaluated the natural course of ISA after bioresorbable vascular scaffold (BRS) implantation using optical coherence tomography (OCT). METHODS: Thirty-two patients (45 BRS) were assessed immediately after BRS implantation and 1 year thereafter using OCT. Acute ISA identified after BRS implantation but absent at follow-up was defined as resolved; otherwise, it was considered persistent. LAISA was defined as newly developed ISA that was identified at follow-up despite complete apposition immediately after BRS implantation. Intra-BRS fibrin-like material (IBF) was identified as an irregular intraluminal mass. ISA percentage was expressed as follows: (number of ISA/total number of BRS struts)×100. RESULTS: Among 45 BRS and 15,894 analyzed BRS struts, 34 and 882 had acute ISA post-procedure, respectively. At follow-up, 92 of 15,364 analyzed struts exhibited late ISA (64 persistent ISA and 28 LAISA). In 15 of 28 struts with LAISA, LAISA occurred at the sites adjacent to post-interventional dissection. Uncovered struts were more frequently observed in late ISA compared to apposed struts (3.7±4.8 vs. 0.58±2.2%, p=0.09). IBF was significantly more common in BRS with late ISA (62.5 vs. 8.1%, p=0.02). Receiver-operating characteristic curve analysis identified a cut-off value of 280µm for acute ISA distance predicting persistent ISA. CONCLUSION: Resolution of acute ISA after BRS is common. The occurrence of LAISA may be infrequent and may be a nidus of stent thrombosis.

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.