A case of early thrombosis following a percutaneous tricuspid valve in valve implantation managed by thrombolysis

Bioprosthetic valve thrombosis is a growing recognized entity, especially with the increasing use of the valve in vale procedures and the advent of new detection technologies (e.g., 4D CT and 4D echocardiography). However, the optimal management strategy in the acute context is not established. This paper presents a case of early thrombosis following the percutaneous tricuspid valve in vale procedure that was successfully managed with thrombolysis.

Fast versus ultra-slow thrombolytic infusion regimens in patients with obstructive mechanical prosthetic valve thrombosis: a pilot randomized clinical trial

Background Thrombolysis is an alternative to surgery for mechanical prosthetic valve thrombosis (MPVT). Randomized clinical trials have yet to test safety and efficacy of a proposed ultraslow thrombolytic infusion regimen. Methods and Results This single-center, open-label, pilot randomized clinical trial randomized adult patients with acute obstructive MPVT to an ultraslow thrombolytic regimen (25 mg of recombinant tissue-type plasminogen activator [rtPA] infused in 25h) and a fast thrombolytic regimen (50 mg of rtPA infused in 6h). If thrombolysis failed, a repeated dose of 25 mg of rtPA for 6h was administered in both groups up to a cumulative dose of 150 mg or the occurrence of a complication. Primary outcome was a complete MPVT resolution (>75% fall in the obstructive gradient by transthoracic echocardiography, <10° limitation in opening and closing valve motion angles by fluoroscopy, and symptom improvement). Key safety outcome was a BARC type III or V major bleeding. Overall, 120 patients, including 63 (52.5%) women, at a mean age of 36.3±15.3 years, were randomized. Complete thrombolysis success was achieved in 51 patients (85.0%) in the ultraslow-regimen group and 47 patients (78.3%) in the fast-regimen group (OR, 1.58; 95% CI, 0.25 to 1.63; P = 0.34). One case of transient ischemic attack and 3 cases of intracranial hemorrhage (absolute risk difference, −12.5%; 95% CI, −23.1% to −1.0%; P = 0.04). were observed only in the fast-regimen group. Conclusions The ultraslow thrombolytic regimen conferred a high thrombosis resolution rate without major complications. Such findings should be replicated in more adequately powered trials (IRCT20181022041406N2).

778 Acute clinical valve thrombosis after transcatheter mitral valve-in-valve replacement

Aims Transcatheter heart valve (THV) thrombosis is a frequent and potentially life-threatening complication of transcatheter mitral valve replacement (TMVR), occurring in approximately 12% of patients (mainly within the first 3 months after the procedure). The majority of THV thromboses is non-obstructive and subclinical, and remains undetected until a routine echocardiogram is performed. Methods A 65 years old male was suffering from post-ischaemic dilated cardiomyopathy and severe left ventricle systolic dysfunction (LVEF 28%), secondary to a previous STEMI in 2010 treated with primary PCI on proximal LAD; after the STEMI he developed a left ventricle aneurysm and a subsequent severe secondary mitral regurgitation. In late 2020 he underwent a surgical valve replacement with a biologic valve (Perimount Magna Mitral Ease n. 27), alongside a left ventricle reshaping (Dor procedure). After a few months, the patient developed worsening dyspnoea and severe exercise intolerance; a transesophageal echocardiogram (TEE) showed an extensive valve degeneration with diffuse leaflet thickening determining severe valve stenosis and regurgitation. The patient was then admitted to the Cardiology department. A coronary angiography was performed, showing good result of previous PCI and excluding other critical stenoses. The patient then underwent a transcatheter valve-in-valve replacement with a Sapien S3 n. 29 in mitral position. The patient was already in chronic therapy with acetilsalicilic acid (ASA), and after the procedure anticoagulant therapy with Warfarin was started. In the post-procedural period the patient developed an acute worsening of the LVEF with severe hypotension, likely due to after-load mismatch; hence, supportive inotropic therapy with Adrenalin and Enoximone was required. A TEE performed 7 days after the procedure showed absence of diastolic excursion of posterior and lateral cusps and leaflet thickening with a 4 mm thrombotic apposition on the ventricular side, determining severe valve stenosis with markedly increased transvalvular gradients (peak gradient 20 mmHg, mean gradient 11 mmHg). A CT scan of the heart confirmed the valve thrombosis on the inferior and lateral leaflets. Results Unfractioned heparin (UFH) was then added to ASA and Warfarin (INR target of 3.0). After 11 days of aggressive antithrombotic therapy a new TEE was performed, showing marked reduction in transvalvular gradients (peak gradient 10 mmHg, mean gradient 5 mmHg) due to partial dissolution of the thrombotic formation. Warfarin was then stopped, and after switching from UFH to Enoxaparin the patient was discharged asymptomatic and in good general conditions, with indication of follow-up with TEE at 1 month. Conclusions Valve-in-valve TMVR is a relatively new and still infrequent procedure, therefore few evidences about its complications are currently available. Thrombosis on these valves is not rare (12%), but usually develops on the atrial side of the leaflets; interestingly, in this patient the thrombosis was on the ventricular side, likely due to an acute reduction in flow velocity caused by the after-load mismatch and the subsequent cardiogenic shock.

Early Outcomes of Emergency Surgery for Left-Sided Mechanical Valve Thrombosis

Background: Valve thrombosis is a potentially lethal complication of mechanical cardiac valves. We examined the clinical characteristics as well as the early outcomes of patients undergoing emergency surgery for left-sided mechanical valve thrombosis. Methods: Between January 2012 and May 2020, 104 consecutive patients were offered an emergency redo surgery for acute mechanical valve thrombosis. Ninety-seven of these patients were included in the current study. Results: The mean age was 34.2 ± 10.3 years. Most of the patients were females (61 patients), and 27 patients (27.8%) were pregnant. The mitral valve was the site of thrombosis in 81 patients. Inadequate anticoagulation was found in 60.8% of patients. The overall early mortality was 32.9% (32 patients) with an operative mortality of 25.7%. Outcomes in the pregnant subgroup tended to be worst with a maternal mortality in the range of 37%, and with fetal and neonatal survival as low as 33.3%. Conclusion: The overall mortality in cases of mechanical valve thrombosis warranting surgery remains high. Since inadequate anticoagulation seems to be one of the major precipitating factors, the current study highlights the need for improvements in anticoagulation practices. The use of tissue valves should also be contemplated more seriously in some younger patients, especially females expressing the desire for future pregnancies.

Transcatheter aortic valve thrombosis: a review of potential mechanisms

Transcatheter aortic valve (TAV) thrombosis has been recognized as a significant problem that sometimes occurs as early as within 30 days after valve implantation, leading to increased concerns of stroke and long-term valve durability. In this article, a critical summary of the relevant literature on identifying potential mechanisms of TAV thrombosis from the perspective of the well-known Virchow's triad, which comprises blood flow, foreign materials and blood biochemistry, is presented. Blood flow mechanisms have been the primary focus thus far, with a general consensus on the flow mechanisms with respect to haemodynamic conditions, the influence of TAV placement and expansion and the influence of coronary flow. Less attention has been paid to the influence of blood biochemistry and foreign materials (and related endothelial damage), with little consensus among studies with regards to platelet and/or microparticle levels post-TAV implantation. Finally, we discuss the future outlook for research with unanswered scientific questions.