Mechanical and surgical bioprosthetic valve thrombosis

Thromboaspiration of a left-sided bioprosthetic valve thrombosis by a mini-access: the Lausanne novel procedure

Left-sided bioprosthesis valve thrombosis (LSBVT) is a challenging complication necessitating invasive interventions. In this study, we introduce a novel, minimally invasive approach. We used a cerebral embolic protection system and an Occlutech cannula connected to an extracorporeal circuit, providing safer thrombus aspiration compared to the AngioVac system. This technique offers a promising alternative for high-risk patients with LSBVT.

Case of postoperative mitral and tricuspid valve repair with large vessel occlusion ischaemic stroke: successfully treated with mechanical thrombectomy extracting subocclusive thrombus containing foreign material

A woman in her 60s with a history of prior ischaemic stroke developed acute onset slurring of speech, left-sided facial droop and left-sided weakness and was found on CT angiography to have a subocclusive thrombus multiple days after undergoing mitral and tricuspid valve repair surgery. A stent retriever and aspiration catheter were used to successfully remove the subocclusive material which was identified as 'foreign material' on histology. Ultimately, the patient demonstrated clinical improvement.Foreign material embolism is a rare but serious complication that can occur during or after mitral and tricuspid valve repair surgery. It can cause ischaemic stroke and prompt recognition and immediate intervention are necessary to prevent serious complications.The case report highlights the successful use of stent retriever-mediated suction thrombectomy to remove a foreign material embolism in a patient. It emphasises the importance of timely intervention to prevent serious complications and shows the potential benefits of this technique.

Deformation of transcatheter heart valves with mitral valve-in-valve

BACKGROUND

The use of oversizing in mitral valve-in-valve (MViV) procedures can lead to non-uniform expansion of transcatheter heart valves (THV). This may have implications for THV durability.

AIMS

The objective of this study was to assess the extent and predictors of THV deformation in MViV procedures.

METHODS

We examined 33 patients who underwent MViV with SAPIEN prostheses. The extent of THV deformation (deformation index, eccentricity, neosinus volume, asymmetric leaflet expansion and vertical deformation) and hypoattenuating leaflet thickening (HALT) were assessed using cardiac computed tomography (CT), performed prospectively at 30 days post-procedure. For descriptive purposes, the THV deformation index was calculated, with values >1.00 representing a more hourglass shape.

RESULTS

Non-uniform underexpansion of THV was common after MViV implantation, with a median expansion area of 74.0% (interquartile range 68.1-84.1) at the narrowest level and a THV deformation index of 1.21 (1.13-1.29), but circularity was maintained with eccentricity ranging from 0.24 to 0.28. The degree of oversizing was a key factor associated with greater underexpansion and a higher deformation index (β=-0.634; p<0.001; β=0.594; p<0.001, respectively). Overall, the incidence of HALT on the 30-day postprocedural CT was 27.3% (9 of 33). Most patients (32 of 33) were on anticoagulation therapy, but the prothrombin time and international normalised ratio (PT-INR) at the time of the CT scan was <2.5 in 23 of 32 patients. Among patients with a PT-INR of <2.5, HALT was predominantly observed with a high THV deformation index of ≥1.18.

CONCLUSIONS

THV deformation, i.e., underexpansion and an hourglass shape, commonly occurs after MViV implantation and is negatively affected by excessive oversizing. Optimising THV expansion during MViV could potentially prevent HALT.

Mechanical Aortic Valve Thrombosis with Heart Failure Successfully Treated with Oral Anticoagulation: A Case Report

Background

The use of anticoagulation is mandatory for prevention of prosthetic valve thrombosis (PVT) worldwide, regardless of the valve type or position in the heart. In case a thrombosis causes symptomatic dysfunction, treatment usually includes the use of thrombolytic therapy or surgery. We report a case of PVT involving a patient with a mechanical aortic valve which was treated entirely with the use of anticoagulation therapy (warfarin).

Case Presentation

A 58-year-old man had an aortic valve replacement using a Carbomedics® mechanical valve due to severe aortic stenosis as a result of a calcific bicuspid native aortic valve. He was commenced on warfarin after surgery which was continued thereafter. He presented to our hospital after three years with shortness of breath at rest. On clinical examination, his condition was poor with a New York Heart Association functional classification of IV. He was in sinus rhythm and had an enlarged heart shadow on chest X-ray. Transesophageal echocardiography (TEE) revealed aortic valve regurgitation with vegetations on the anterior valve leaflet causing reduced hemi leaflet motility and a mean pressure gradient of 50 mmHg. Cinefluoroscopy revealed a dysfunctional mechanical valve leaflet. Surgery was at high risk of mortality due to the patient's clinical status and he was continued on warfarin therapy with close monitoring. Cinefluoroscopy and echocardiography done six months later revealed complete dissolution of thrombus and a normally functioning mechanical aortic valve.

Conclusion

Only a few cases of symptomatic, thrombotic mechanical aortic valve were entirely treated with anticoagulation only. Our patient is one such case who had resolution of symptoms and improvement on NYHA functional classification (IV to I).

The Complex Management of Mechanical Prosthetic Valve Thrombosis

Mechanical prosthetic valve thrombosis (PVT) is a serious condition that is associated with various life-threatening complications. The utilization of multimodality imaging techniques is critical in identifying this etiology. Its management is complex and often requires repeat surgical valve replacements. Our report describes the case of a 48-year-old female who presented with mechanical mitral valve thrombosis in the setting of subtherapeutic anticoagulation. Due to her complex surgical history, nonsurgical therapeutic options were initially pursued for management. Through shared decision-making and after exhaustion of other alternatives, she was maintained on optimized medical therapy and was scheduled for repeat elective surgery. After compliance with medical therapy and close monitoring, she improved significantly, and her underlying pathology completely resolved, eliminating the need for surgery. This report indicates that the management of mechanical prosthetic valve thrombosis should be individualized and emphasizes the importance of involving a multidisciplinary team of medical and surgical professionals to achieve the best clinical outcomes.

Heart failure and excess mortality after aortic valve replacement in aortic stenosis

INTRODUCTION

In aortic stenosis (AS), the heart transitions from adaptive compensation to an AS cardiomyopathy and eventually leads to decompensation with heart failure. Better understanding of the underpinning pathophysiological mechanisms is required in order to inform strategies to prevent decompensation.

AREAS COVERED

In this review, we therefore aim to appraise the current pathophysiological understanding of adaptive and maladaptive processes in AS, appraise potential avenues of adjunctive therapy before or after AVR and highlight areas of further research in the management of heart failure post AVR.

EXPERT OPINION

Tailored strategies for the timing of intervention accounting for individual patient's response to the afterload insult are underway, and promise to guide better management in the future. Further clinical trials of adjunctive pharmacological and device therapy to either cardioprotect prior to intervention or promote reverse remodeling and recovery after intervention are needed to mitigate the risk of heart failure and excess mortality.

Innovative IntraValvular Impedance Sensing Applied to Biological Heart Valve Prostheses: Design and In Vitro Evaluation

Subclinical valve thrombosis in heart valve prostheses is characterized by the progressive reduction in leaflet motion detectable with advanced imaging diagnostics. However, without routine imaging surveillance, this subclinical thrombosis may be underdiagnosed. We recently proposed the novel concept of a sensorized heart valve prosthesis based on electrical impedance measurement (IntraValvular Impedance, IVI) using miniaturized electrodes embedded in the valve structure to generate a local electric field that is altered by the cyclic movement of the leaflets. In this study, we investigated the feasibility of the novel IVI-sensing concept applied to biological heart valves (BHVs). Three proof-of-concept prototypes of sensorized BHVs were assembled with different size, geometry and positioning of the electrodes to identify the optimal IVI-measurement configuration. Each prototype was tested in vitro on a hydrodynamic heart valve assessment platform. IVI signal was closely related to the electrodes' positioning in the valve structure and showed greater sensitivity in the prototype with small electrodes embedded in the valve commissures. The novel concept of IVI sensing is feasible on BHVs and has great potential for monitoring the valve condition after implant, allowing for early detection of subclinical valve thrombosis and timely selection of an appropriate anticoagulation therapy.

Prosthetic Aortic Valve Thrombosis

Prosthetic valve thrombosis is the second leading cause of prosthetic valve deterioration and is being more readily diagnosed with the use of echocardiography and multidetector cardiac CT. Presentation of valve thrombosis can be acute or subacute and any change in clinical status of a patient with a prosthetic valve should raise a suspicion of prosthetic valve thrombosis. Diagnosis entails detailed clinical examination and comprehensive imaging. The choice of therapeutic options includes anticoagulation, fibrinolytic therapy, or valve replacement. Antiplatelet and anticoagulation therapy remain the mainstay of thrombosis prevention in patients with a prosthetic valve and a personalized approach is required to optimize prosthetic valve function and minimize the risk of bleeding.

A Novel Thrombolytic Regimen for Mechanical Prosthetic Valve Thrombosis in a Patient With Antiphospholipid Syndrome

Management of mechanical prosthetic valve thrombosis (PVT) includes medical and surgical options. Standard medical treatment involves thrombolytic therapy with repeated slow infusions of low-dose IV tissue plasminogen activator (t-PA). The evidence for managing mechanical PVT that does not respond to the standard t-PA dosing is limited in the setting of an exacerbating hypercoagulable condition. We present a case of a patient with a history of antiphospholipid syndrome who presented with a probable thromboembolic myocardial infarction secondary to a mechanical mitral valve thrombosis that did not improve with systemic anticoagulation and repeated standard t-PA dosing but rapidly resolved with ultraslow, high-dose t-PA.

Shear-Mediated Platelet Activation is Accompanied by Unique Alterations in Platelet Release of Lipids

INTRODUCTION

Platelet activation by mechanical means such as shear stress exposure, is a vital driver of thrombotic risk in implantable blood-contacting devices used in the treatment of heart failure. Lipids are essential in platelets activation and have been studied following biochemical activation. However, little is known regarding lipid alterations occurring with mechanical shear-mediated platelet activation.

METHODS

Here, we determined if shear-activation of platelets induced lipidome changes that differ from those associated with biochemically-mediated platelet activation. We performed high-resolution lipidomic analysis on purified platelets from four healthy human donors. For each donor, we compared the lipidome of platelets that were non-activated or activated by shear, ADP, or thrombin treatment.

RESULTS

We found that shear activation altered cell-associated lipids and led to the release of lipids into the extracellular environment. Shear-activated platelets released 21 phospholipids and sphingomyelins at levels statistically higher than platelets activated by biochemical stimulation.

CONCLUSIONS

We conclude that shear-mediated activation of platelets alters the basal platelet lipidome. Further, these alterations differ and are unique in comparison to the lipidome of biochemically activated platelets. Many of the released phospholipids contained an arachidonic acid tail or were phosphatidylserine lipids, which have known procoagulant properties. Our findings suggest that lipids released by shear-activated platelets may contribute to altered thrombosis in patients with implanted cardiovascular therapeutic devices.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12195-021-00692-x.

Mechano-regulated cell-cell signaling in the context of cardiovascular tissue engineering

Cardiovascular tissue engineering (CVTE) aims to create living tissues, with the ability to grow and remodel, as replacements for diseased blood vessels and heart valves. Despite promising results, the (long-term) functionality of these engineered tissues still needs improvement to reach broad clinical application. The functionality of native tissues is ensured by their specific mechanical properties directly arising from tissue organization. We therefore hypothesize that establishing a native-like tissue organization is vital to overcome the limitations of current CVTE approaches. To achieve this aim, a better understanding of the growth and remodeling (G&R) mechanisms of cardiovascular tissues is necessary. Cells are the main mediators of tissue G&R, and their behavior is strongly influenced by both mechanical stimuli and cell-cell signaling. An increasing number of signaling pathways has also been identified as mechanosensitive. As such, they may have a key underlying role in regulating the G&R of tissues in response to mechanical stimuli. A more detailed understanding of mechano-regulated cell-cell signaling may thus be crucial to advance CVTE, as it could inspire new methods to control tissue G&R and improve the organization and functionality of engineered tissues, thereby accelerating clinical translation. In this review, we discuss the organization and biomechanics of native cardiovascular tissues; recent CVTE studies emphasizing the obtained engineered tissue organization; and the interplay between mechanical stimuli, cell behavior, and cell-cell signaling. In addition, we review past contributions of computational models in understanding and predicting mechano-regulated tissue G&R and cell-cell signaling to highlight their potential role in future CVTE strategies.

Long-Term Stability and Biocompatibility of Pericardial Bioprosthetic Heart Valves

The use of bioprostheses for heart valve therapy has gradually evolved over several decades and both surgical and transcatheter devices are now highly successful. The rapid expansion of the transcatheter concept has clearly placed a significant onus on the need for improved production methods, particularly the pre-treatment of bovine pericardium. Two of the difficulties associated with the biocompatibility of bioprosthetic valves are the possibilities of immune responses and calcification, which have led to either catastrophic failure or slow dystrophic changes. These have been addressed by evolutionary trends in cross-linking and decellularization techniques and, over the last two decades, the improvements have resulted in somewhat greater durability. However, as the need to consider the use of bioprosthetic valves in younger patients has become an important clinical and sociological issue, the requirement for even greater longevity and safety is now paramount. This is especially true with respect to potential therapies for young people who are afflicted by rheumatic heart disease, mostly in low- to middle-income countries, for whom no clinically acceptable and cost-effective treatments currently exist. To extend longevity to this new level, it has been necessary to evaluate the mechanisms of pericardium biocompatibility, with special emphasis on the interplay between cross-linking, decellularization and anti-immunogenicity processes. These mechanisms are reviewed in this paper. On the basis of a better understanding of these mechanisms, a few alternative treatment protocols have been developed in the last few years. The most promising protocol here is based on a carefully designed combination of phases of tissue-protective decellularization with a finely-titrated cross-linking sequence. Such refined protocols offer considerable potential in the progress toward superior longevity of pericardial heart valves and introduce a scientific dimension beyond the largely disappointing 'anti-calcification' treatments of past decades.

Transcatheter Mitral Valve Replacement and Thrombosis: A Review

Mitral regurgitation is the most prevalent form of moderate or severe valve disease in developed countries. Surgery represents the standard of care for symptomatic patients with severe mitral regurgitation, but up to 50% of patients are denied surgery because of high surgical risk. In this context, different transcatheter options have been developed to address this unmet need. Transcatheter mitral valve replacement (TMVR) is an emergent field representing an alternative option in high complex contexts when transcatheter mitral valve repair is not feasible or suboptimal due to anatomical issues. However, TMVR is burdened by some device-specific issues (device malposition, migration or embolization, left ventricular outflow tract obstruction, hemolysis, thrombosis, stroke). Here we discuss the thrombotic risk of TMVR and current evidence about anticoagulation therapy after TMVR.

Cross-Linking Porcine Pericardium by 3,4-Dihydroxybenzaldehyde: A Novel Method to Improve the Biocompatibility of Bioprosthetic Valve

Heart valve replacement is an effective therapy for patients with moderate to severe valvular stenosis or regurgitation. Most bioprosthetic heart valves applied clinically are based on cross-linking with glutaraldehyde (GLUT), but they have some drawbacks like high cytotoxicity, severe calcification, and poor hemocompatibility. In this study, we focused on enhancing the properties of bioprosthetic heart valves by cross-linking with 3,4-dihydroxybenzaldehyde (DHBA). The experiment results revealed that compared with GLUT cross-linked porcine pericardium (PP), the relative amount of platelets absorbed on the surface of DHBA cross-linked PP decreased from 0.294 ± 0.034 to 0.176 ± 0.028, and the activated partial thromboplastin time (APTT) increased from 9.9 ± 0.1 to 15.2 ± 0.1 s, indicating improved hemocompatibility. Moreover, anticalcification performance and cytocompatibility were greatly enhanced by DHBA cross-linking. In conclusion, the properties of bioprosthetic valves could be effectively improved by processing valves with a DHBA-based cross-linking method.

Aortic root thrombus after left ventricular assist device implantation and aortic valve replacement

Data on the risk of aortic root thrombosis in patients with aortic valve replacement (AVR) and left ventricular assist device (LVAD) surgery are scarce. Two out of nine patients receiving AVR concomitant with LVAD surgery and two out of two patients receiving AVR on LVAD support, at our centre, developed an aortic root thrombus, all diagnosed with computed tomography (CT) angiography. These results demonstrate that patients with concomitant AVR and LVAD surgery, or AVR on LVAD support, have an increased risk of aortic root thrombosis. Therefore, early anti-thrombotic therapy and vigilant diagnostic follow-up, using CT scans, are warranted to prevent thromboembolic events.

Cardiac Imaging After Ischemic Stroke or Transient Ischemic Attack

PURPOSE OF REVIEW

Cardiac imaging after ischemic stroke or transient ischemic attack (TIA) is used to identify potential sources of cardioembolism, to classify stroke etiology leading to changes in secondary stroke prevention, and to detect frequent comorbidities. This article summarizes the latest research on this topic and provides an approach to clinical practice to use cardiac imaging after stroke.

RECENT FINDINGS

Echocardiography remains the primary imaging method for cardiac work-up after stroke. Recent echocardiography studies further demonstrated promising results regarding the prediction of non-permanent atrial fibrillation after ischemic stroke. Cardiac magnetic resonance imaging and computed tomography have been tested for their diagnostic value, in particular in patients with cryptogenic stroke, and can be considered as second line methods, providing complementary information in selected stroke patients. Cardiac imaging after ischemic stroke or TIA reveals a potential causal condition in a subset of patients. Whether systematic application of cardiac imaging improves outcome after stroke remains to be established.

Short-Term Clinical Follow-Up After Thrombolytic Therapy in Patients With Prosthetic Valve Thrombosis: A Single-Center Experience

Background

Thrombolytic therapy has evolved as an alternative to surgery for prosthetic valve thrombosis (PVT). Therefore, this retrospective, single-center study aimed to evaluate the clinical profile of PVT and the role of thrombolytic therapy in patients with PVT.

Methods

Data from a total of 16 consecutive patients with PVT enrolled between January 2017 and January 2018 at a tertiary care center in India were retrospectively evaluated. PVT was diagnosed based on clinical presentation, transthoracic echocardiography, and fluoroscopy. All patients received 0.25 MU intravenous (IV) bolus streptokinase over 30 min, followed by a 0.1 MU/h IV infusion for a maximum of 72 h. Transthoracic echocardiography and fluoroscopy were repeated after completion of thrombolysis session. The clinical endpoints were death and hemodynamic success within 24 h of thrombolytic therapy or during the hospital stay, and major complications, including stroke or major bleeding (intracranial bleed or bleeding requiring transfusion or surgical treatment) during the hospital stay and within 3 months of thrombolytic therapy.

Results

The median age of the patients was 40 ± 11.60 years and about 62.5% (n = 10) were females. The median time between the valve placement and presentation for PVT was 3 years (range: 1 - 4 years). The peak gradient across the thrombotic mitral and aortic valve was 43.79 ± 18.47 and 93.5 ± 33.11 mmHg, respectively. At 3 days post-thrombolysis, peak gradient across both mitral valve (15.91 ± 7.56; mean gradient: 8.45 ± 4.01) and aortic valve (23.50 ± 6.45; mean gradient: 13.60 ± 3.83) decreased significantly (P ≤ 0.05). The thrombolytic therapy was successful in 13 (81.25%) patients. While, two (12.50%) patients died, none developed stroke or myocardial infarction during the study period.

Conclusions

The present study with short-term follow-up demonstrated the acceptable clinical efficacy of thrombolytic therapy. However, larger trials with a greater number of patients and longer follow-up are warranted to establish the safety and effectiveness of thrombolytic therapy in patients with PVT.

Cardiac imaging after ischemic stroke : Echocardiography, CT, or MRI?

About 20–25% of all ischemic strokes are of cardioembolic etiology, with atrial fibrillation and heart failure as the most common underlying pathologies. Diagnostic work-up by noninvasive cardiac imaging is essential since it may lead to changes in therapy, e.g., in—but not exclusively—secondary stroke prevention. Echocardiography remains the cornerstone of cardiac imaging after ischemic stroke, with the combination of transthoracic and transesophageal echocardiography as gold standard thanks to their high sensitivity for many common pathologies. Transesophageal echocardiography should be considered as the initial diagnostic tool when a cardioembolic source of stroke is suspected. However, to date, there is no proven benefit of transesophageal echocardiography-related therapy changes on the main outcomes after ischemic stroke. Based on the currently available data, cardiac computed tomography and magnetic resonance imaging should be regarded as complementary methods to echocardiography, providing additional information in specific situations; however, they cannot be recommended as first-line modalities.