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Eur Heart J Case Rep
Eur Heart J Case Rep
ehjcr
European Heart Journal. Case Reports
2514-2119
Oxford University Press UK

10.1093/ehjcr/ytae438
ytae438
Case Report
AcademicSubjects/MED00200
Eurheartj/1
Eurheartj/3
Eurheartj/4
Late-onset left atrial appendage occlusion device–related thrombus attributed to mitral bioprosthetic stenosis: a case report
https://orcid.org/0009-0001-4167-1164
Rana Aakash Central Arkansas Veterans Affairs Health System, 4300, W 7th Street, Little Rock, AR 72205, USA

Xu Jack Novant Health Forsyth Medical Center, Winston-Salem, NC, USA

Alturkmani Hani University of Arkansas for Medical Sciences, 6301 West Markham St, Slot 532, Little Rock, AR 72205, USA

Dhar Gaurav Rush University Medical Center, Chicago, IL, USA

https://orcid.org/0000-0002-2404-1152
Vallurupalli Srikanth University of Arkansas for Medical Sciences, 6301 West Markham St, Slot 532, Little Rock, AR 72205, USA

Vrachatis Dimitrios A Handling Editor
Manninger Martin Editor
Hillmann Henrike Aenne Katrin Editor
Wardill Tom Editor
Corresponding author. Tel: +1 217 377 5578, Fax: +1 501 434 6088, Email: svallurupalli@uams.edu
Conflict of interest. None declared.

9 2024
23 8 2024
23 8 2024
8 9 ytae43815 2 2024
18 6 2024
15 8 2024
10 9 2024
© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.
2024
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Abstract

Background

Left atrial appendage occlusion (LAAO) is an alternative to anticoagulation for stroke prevention in select patients with atrial fibrillation (AF). In this study, we describe the case of a patient with delayed device-related thrombus (DRT) at 13 months post-LAAO in a setting of atrial stasis due to a worsening mitral bioprosthetic stenosis.

Case summary

A 69-year-old woman with a history of rheumatic mitral stenosis and regurgitation post-bioprosthetic mitral valve replacement (6 years prior) and paroxysmal AF was referred for percutaneous LAAO due to recurrent severe gastrointestinal bleeding while on anticoagulation. She underwent an uncomplicated LAAO, for which a 35 mm Watchman Flx device was used. Peri-procedural transoesophageal echocardiogram (TEE) at the time of implant showed thickened and calcified mitral bioprosthetic leaflets and a mild mitral stenosis. Her 45-day post-LAAO TEE showed a mild mitral stenosis and no peri-device leak or DRT. At 12 months, the patient had worsening exertional dyspnoea and pedal oedema. Her 12-month transthoracic echocardiogram (TTE) showed a moderate mitral stenosis and LAAO remained free of DRT. Her symptoms were deemed secondary from a worsening mitral valve stenosis. Mitral valve-in-valve (MViV) replacement was planned because the patient was deemed a prohibitive risk for a redo surgical replacement. Transthoracic echocardiogram on the day of MViV showed a large thrombus on the LAAO device. MViV was postponed. After the patient completed 45 days of anticoagulation with warfarin, a repeat TTE was performed, which showed a resolution of DRT. Transcatheter MViV was performed successfully.

Discussion

This case demonstrates that increased stasis and left atrial dysfunction from prosthetic mitral stenosis can be a risk factor for late DRT after successful LAAO. The use of a LAAO occlusion device in the presence of a mitral bioprosthesis requires more frequent echocardiographic monitoring to assess both the function of the prosthesis and a delayed formation of thrombus. More studies need to be conducted to assess the safety of percutaneous LAAO devices in those with mitral bioprosthesis.

Device-related thrombus
Left atrial appendage occlusion
Atrial fibrillation
Bioprosthetic valve stenosis
Case report
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pmcLearning points

To be able to recognize that device-related thrombus (DRT) can occur at any time after left atrial appendage occlusion (LAAO).

To advocate for follow-up imaging 1 year or more after LAAO placement in patients at risk for DRT.

Worsening left atrial stasis can predispose a patient to DRT.

Introduction

Left atrial appendage occlusion (LAAO) is an alternative to anticoagulation for stroke prevention in select patients with atrial fibrillation (AF).1 For all individuals diagnosed with AF and at an increased risk of thromboembolism (especially those with a CHA2DS2-VASc score of ≥2 in women and ≥1 in men), there is a recommendation for thromboembolic prophylaxis using oral anticoagulant therapy (OAT).2 The primary guidelines and international consensus documents suggest LAAO for patients requiring thromboembolic prophylaxis but are unable to use oral anticoagulants due to contraindications (Class IIb recommendation).2,3 With an increase in operator experience and improved device engineering, procedural complications have decreased.4 An uncommon complication after LAAO is device-related thrombus (DRT).5–7 Most cases of DRT occur within 6 months of implantation, prior to endothelialization of the device, and its incidence reduces markedly afterwards. In this study, we describe an unusual case of a patient with large late DRT at 13 months post-LAAO in a setting of significant atrial stasis caused by new-onset mitral bioprosthetic valve stenosis.

Summary figure

Case timeline	
X-2 month	Referred for left atrial appendage occlusion (LAAO) due to recurrent severe gastrointestinal bleeding while on anticoagulation for atrial fibrillation in a setting of prior bioprosthesis mitral valve replacement	
X	Left atrial appendage occlusion with a 35 mm Watchman Flx device placed. Transoesophageal echocardiogram (TEE) showed thickened and calcified mitral bioprosthetic leaflets with elevated gradients [mean gradient 4 mm at heart rate (HR) 70 b.p.m., pressure half time 68 ms]	
X + 45 days	Transthoracic echocardiogram showed no peri-device leak or device-related thrombus (DRT). Transoesophageal echocardiogram showed that the leaflets of the mitral bioprosthesis were calcified and restricted, but Doppler evaluation did not suggest significant stenosis (mean gradient 4 mm at HR 60 b.p.m., pressure half time 78 ms)
	
X + 12 months	The patient had worsening exertional dyspnoea and pedal oedema. Transthoracic echocardiogram showed a worsening bioprosthetic mitral stenosis with calcified thickened leaflets (a mean gradient of 7 mmHg at a HR of 62 b.p.m., pressure half time 200 ms)
	
X + 12.5 months	Symptoms likely secondary from a worsening mitral valve stenosis and seen by the heart team for evaluation. Plan for MViV in the next 2 weeks	
X + 13 months	Transoesophageal echocardiogram on the day of planned MViV revealed a large thrombus (1.7 cm × 1.3 cm) on the LAAO device (a mean gradient of 8 mm at a HR of 50 b.p.m., pressure half time 280 ms). The procedure was postponed. Warfarin was started and continued for 45 days

	
X + 14.5 months	Transoesophageal echocardiogram showed a resolution of DRT. The transcatheter MViV procedure was performed. The patient was discharged from hospital	
AF, atrial fibrillation; LAAO, left atrial appendage occlusion); MViV, mitral valve-in-valve); TEE, transoesophageal echocardiogram; X, day of implantation of LAAO.

Case presentation

A 69-year-old woman with a history of rheumatic mitral stenosis and regurgitation post-bioprosthetic mitral valve replacement with a 31 mm Medtronic Mosaic prosthesis (6 years prior), paroxysmal AF, scleroderma, Stage III chronic kidney disease, coronary artery disease, heart failure with reduced ejection fraction, hypertension, and hyperlipidaemia was referred for percutaneous LAAO due to recurrent severe gastrointestinal bleeding while initially on warfarin and then on apixaban (Class IIb recommendation).2 On physical examination, her blood pressure was 158/75 mmHg, heart rate (HR) was 50 b.p.m., and oxygen saturation was 99% on room air. Her examination was unremarkable, except for the presence of a mild bilateral lower-extremity oedema. The patient underwent an uncomplicated LAAO, for which a 35 mm Watchman Flx device was used. Peri-procedural transoesophageal echocardiogram (TEE) at the time of implant showed thickened and calcified mitral bioprosthetic leaflets with elevated gradients (mean gradient 4 mm at HR 70 b.p.m., pressure half time 68 ms) but no evidence of significant stenosis. Apixaban 5 mg BID was initiated. Due to a lack of symptoms, clinical follow-up and surveillance of prosthetic function were planned.

Her 45-day post-LAAO TEE showed no peri-device leak or DRT (Figure 1A). The leaflets of the mitral bioprosthesis were calcified and restricted, but Doppler evaluation did not suggest significant stenosis (mean gradient 4 mm at HR 60 b.p.m., pressure half time 78 ms). Apixaban 5 mg BID was discontinued, and a daily dose of aspirin 81 mg was initiated. Twelve months later, she presented with worsening exertional dyspnoea and pedal oedema. A repeat TEE showed a worsening bioprosthetic mitral stenosis with calcified thickened leaflets (a mean gradient of 7 mmHg at an HR of 62 b.p.m., pressure half time 200 ms). The LAAO device remained free of DRT (Figure 1B and Supplementary material online, Video S1). Her symptoms were possibly attributed to a rapidly progressive bioprosthetic mitral valve stenosis and she was referred to the heart team. She underwent a workup for valve intervention and was deemed as a prohibitive risk for a redo surgical replacement, and therefore, a transcatheter mitral valve-in-valve (MViV) replacement was planned.

Figure 1 Representative images of a Watchman Flx device and corresponding mitral prosthetic Doppler evaluation by transoesophageal echocardiography performed at different time intervals after implant. (A) No device-related thrombus formation on left atrial appendage occlusion at the 45-day post-implant while the patient was on apixaban 5 mg b.i.d. (B) No device-related thrombus formation on left atrial appendage occlusion at 12 months’ post-implant while the patient was on aspirin 81 mg daily. (C) Device-related thrombus formation on left atrial appendage occlusion (arrow) at 13 months’ post-implant while the patient was on aspirin 81 mg daily. HR, heart rate; LAAO, left atrial appendage occlusion; PHT, pressure half time.

Transoesophageal echocardiogram on the day of her planned MViV (13 months after her LAAO) revealed a large thrombus measuring 1.7 cm × 1.3 cm on the LAAO device (Figure 1C and Supplementary material online, Video S2). The procedure was discontinued and she was started on anticoagulation with warfarin and a target international normalized ratio (INR) of 3–3.5. No major bleeding episodes occurred while the patient was on warfarin for the DRT. After 45 days of anticoagulation, a repeat TEE showed a resolution of DRT. The transcatheter MViV procedure with a 29 mm Edwards Sapien S3 was performed successfully. At hospital discharge, warfarin was resumed after MViV due to prior thrombus formation with LAAO. Four weeks after discharge, the patient was admitted to the hospital for a septic shock. Unfortunately, the patient passed away during this period of admission.

Discussion

Device-related thrombus is a known complication of LAAO and is associated with major ischaemic events. Its risk factors are iatrogenic pericardial effusion, hypercoagulable state, renal insufficiency, non-paroxysmal AF, and deep LAAO implant. Device-related thrombus occurs in around 3–4% of patients post-LAAO.8 It can be divided into—early DRT (detection within 6 months after LAAO) and late DRT (detection later than 6 months after LAAO) and is associated with a significantly increased risk of ischaemic events and mortality.9 Device-related thrombus is managed by a reinitiation of anticoagulation, but choice and duration are not supported by good quality evidence.10While DRT within the first year of implant can be attributed to a delayed endothelialization of the device, the risk factors for late DRT have been less well understood. Anticoagulation after placement of LAAO depends on the type of device placed, and there is significant practice variation around the world. The primary regimens testing for the Watchman device consisted of an oral anticoagulant (warfarin with a target INR of 2 to 3 or direct oral anticoagulant) plus aspirin (81–325 mg daily) for 45 days, followed by once-daily clopidogrel 75 mg plus aspirin (81–325 mg) for 6 months, and thereafter, once-daily aspirin (81–325 mg) indefinitely.11 In many countries, dual antiplatelet therapy (without oral anticoagulants) has now become common after device implant. However, the effects of different anticoagulation regimens on the incidence of DRT are unknown.

In valvular AF, both direct anticoagulants and LAAO are contraindicated due to a high risk of left atrial thrombi, and warfarin is the drug of choice.12However, there are scarce data to guide anticoagulation choices after successful mitral valve replacement. While the obstructive mitral valve process is resolved, significant left atrial fibrosis and dysfunction often persist. In the case of the patient in this study, apixaban was given for 6 years after mitral valve replacement, with no thromboembolic events occurring. However, as this patient case illustrates, as the mitral prosthesis degenerates and transmitral gradients increase, a worsening left atrial stasis can promote a thrombotic milieu.

This case illustrates the importance of worsening left atrial stasis in the pathogenesis of late DRT. At 45 days and 12 months post-LAAO, there was no evidence of DRT. However, a worsening bioprosthetic mitral stenosis and resulting left atrial stasis in the milieu of a scarred left atrium from rheumatic heart disease likely predisposed the patient to late DRT.

Due to the large size of the DRT and its proximity to the mitral bioprosthesis, transcatheter mitral valve replacement was discontinued. After resolution with warfarin, successful MViV was performed.

Conclusion

The increased stasis and left atrial dysfunction can be a risk factor for late DRT after successful LAAO. The presence of a mitral bioprosthesis should necessitate a closer echocardiographic monitoring of both prosthetic function and thrombus formation in those with a percutaneous LAAO device.

Lead author biography

Aakash Rana is a hospitalist at the Central Arkansas Veterans Healthcare System in Little Rock, Arkansas. He plans to obtain further training in cardiology.

Supplementary Material

ytae438_Supplementary_Data

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports online.

Consent: The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patient’s next of kin in line with COPE guidance.

Funding: No funding provided.

Data availability

The authors confirm that all data supporting the findings of this case report are available within the manuscript and its online Supplementary material.
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