Non-Obstructive Thrombosis of Mechanical Mitral Prosthesis: About a Case Report and Literature Review

Introduction: Mechanical mitral valve prostheses are vital for patients with mitral valve disease. While obstruction is a well-recognized complication, non-obstructive dysfunction remains less understood. We present a case of non-obstructive mechanical mitral prosthesis to highlight its clinical importance and management challenges. Case Presentation: A 45-year-old female, who had undergone mechanical mitral valve replacement 9 years prior, presented with dysarthria and facial paralysis. Transthoracic echocardiography revealed preserved prosthesis function with no apparent obstruction. However, transesophageal echocardiography confirmed the non-obstructive thrombosis of the mitral prothesis. We opted for a medical treatment consisting in optimizing anticoagulation with the addition of aspirin. The evolution was favorable with complete regression of the thrombus at the control TEO. Discussion: Non-obstructive mechanical mitral prosthesis is a rare entity, often characterized by atypical symptoms. This case emphasizes the importance of comprehensive assessment beyond prosthetic valve gradients. as well as the importance of combining several imaging methods, including radio cinema and TEO. Surgical intervention wasn’t necessary, as the medical treatment was sufficient. Conclusion: Non-obstructive mechanical mitral prosthesis dysfunction can be challenging to diagnose but is crucial to consider in symptomatic patients with mechanical valves. This case underscores the need for a multidimensional approach, including advanced imaging techniques, to uncover and manage non-obstructive prosthesis dysfunction, ultimately improving patient outcomes and quality of life.


Introduction
Prosthesis thrombosis is a relatively rare entity, but it can be very serious, threatening the patient's vital prognosis.There are two types of prosthesis thrombosis: obstructive and non-obstructive.Non-obstructive prosthetic valve thrombosis is frequently detected by transesophageal echocardiography (TEE), which is the method of choice for detecting the 2 significance, and outcome of this event are not clear, which makes treatment difficult [2].We aim to report the clinical and radiological of this case in order to clarify the attitude to adopt when faced with non-obstructive prosthetic mitral valve thrombosis.

Case presentation
We describe the case of a 45-year-old female who underwent A radio cinema was performed (figure 1), revealing a wellfunctioning mechanical prosthesis with good opening and closing of its wings.In our patient's case, in line with the literature, given that the thrombus was small (less than 10mm) and not very mobile, and given that she was well anticoagulated, we opted to increase the therapeutic target of her INR (current target between 3 and 4), with the addition of 100mg of aspirin per day, while making the patient aware of the risk of bleeding.As shown in the presentation above, the evolution was marked by the disappearance of the thrombus at the onemonth follow-up transesophageal echocardiogram, with no notable hemorrhagic events.Ethical approval: As international standard, written ethical approval has been collected and preserved by the authors.

Conclusion
mitral valve replacement for very tight mitral narrowing in 2014 with a Saint-Jude double-fin prosthesis with tricuspid plasty, with a history of ischemic stroke in 2016 on antivitamin K (VKA) based anticoagulation, who presents to the emergency department with dysarthria and facial paralysis evolving since 48h.Clinical examination revealed a conscious patient 15/15, normotensive to 127/72 mmHg, normocardial to 67 bpm, who was 98% saturated with air, with no clinical signs of heart failure.The electrocardiogram showed atrial fibrillation at 60 bpm with no repolarization disorders.Cerebral computed tomography (CT) scan revealed a subacute left capsulothalamic ischemic lesion with no hemorrhagic infarction.Cerebral magnetic resonance imaging (MRI) revealed several bilateral ischemic lesions of different ages with no abnormalities on the angiographic sequences.Ultrasound of the supra-aortic vessels revealed diffuse atheromatous disease with no significant stenosis or hemodynamic impact.Transthoracic echocardiography revealed a non-dilated, nonhypertrophied left ventricle with good global and segmental contractility; ejection fraction was 57% in Simpson biplane.The mechanical double-winged prosthesis in the mitral position with good mobility, mean gradient was at 4 mmHg, patency index was 0. 95, effective valve area was 2.1cm2, mitral E wave of 1.07 m/s, and absence of any thrombus detectable or cardiac vegetation.Right ventricle function was altered; excursion of the tricuspid ring at 14mm.There was no pulmonary hypertension or significant aortic valve disease.

Figure 1 :
Figure 1: Radio-cinema showing wings of valve mitral prothesis in full opening.

Figure 2 :
Figure 2: The Arrow indicates a non-obstructive thrombus on the mitral valve prosthesis.

Figure 3 :
Figure 3: Transesophageal ultrasound showing disappearance of the thrombus.
In conclusion, this case report sheds light on the rare yet clinically significant occurrence of non-obstructive mitral valve thrombosis.While typically overshadowed by obstructive forms of thrombosis, non-obstructive thrombi can pose diagnostic and management challenges.Through a thorough analysis of this case, we underscore the importance of considering this entity in the differential diagnosis of patients with mitral valve pathologies.Early detection, careful monitoring, and tailored anticoagulation strategies are essential in preventing embolic complications and improving patient outcomes.Further research and awareness in this area are crucial for enhancing our understanding and management of non-obstructive mitral valve thrombosis.Consent for publication: Written informed consent was obtained from the patient for publication of this case report and any accompanying images.