Bioprosthetic aortic valve thrombosis under effective direct oral anticoagulant therapy

With the increase in transcatheter procedures, the use of bioprosthetic valves has become more frequent in clinical practice. However, the optimal antithrombotic management of patients with bioprosthetic valves remains controversial. In this case report, we describe a patient with a bioprosthetic aortic valve who developed a thrombus while receiving effective dose direct oral anticoagulant (DOAC) therapy. A 73-year-old male patient with a bioprosthetic aortic valve replacement 2 years prior presented with a mobile thrombus and early degeneration of the valve, detected during routine follow-up while being treated with apixaban. Although the valve thrombus regressed after switching to a different anticoagulant drug, we observed that the decreased but still high gradient persisted due to the early degeneration. Anticoagulant management of bioprosthetic valve patients demands careful attention. Although evidence supporting the use of DOACs is growing, close patient follow-up and further evaluation in case of doubt remain critical. The development of a thrombus in a bioprosthetic valve patient who is receiving anticoagulation therapy, as in this case, highlights the need for optimal management to prevent thromboembolic complications and valve degeneration.

Mechanical valve thrombosis: current management and differences between guidelines

All foreign bodies inserted in the circulatory system are thrombogenic and require temporary or lifelong antithrombotic therapies to prevent thrombosis. The adequate level of anticoagulation during the first few months determines the long-term durability, particularly for mechanical prostheses;2 however also for biological valves. Suboptimal anticoagulation is the most frequent source of mechanical valve thrombosis (MVT). The patient's clinical presentation decides how mechanical prosthetic valve obstruction is managed. If the mechanical valve thrombosis is obstructive and the patient is in a critical condition with hemodynamic instability, an immediate surgical intervention should be performed. The thrombolytic treatment is an option for left mechanical valve thrombosis in patients who have high surgical risk and no contraindications and also for right heart valve thrombosis. In non-obstructive thrombosis on the mechanical valve, patients can be asymptomatic, requiring optimization of the anticoagulant treatment. Both obstructive and non-obstructive thrombus generated on the mechanical prosthesis can result in embolic events. After anticoagulant treatment, if the thrombus persists the indication is for thrombolytic treatment or redo surgery. Pannus can also cause obstruction of the prosthesis for which surgical treatment is the only option. All these clinical scenarios seem to have a simple solution in terms of surgery vs thrombolysis vs effective anticoagulation, but the real-world clinical experience could be different. For example, the same patient with some common comorbidities, non-obstructive mechanical valve thrombosis, and symptomatic only by repeated systemic embolizations, can go through all these 3 therapeutic options, due to MVT's unpredictable nature. Therefore, treatment indications can intersect both on the time axis and depending on the patient's clinical status and the expertise of the center where he is hospitalized. Moreover, the European and American guidelines show subtle but important differences. The aim of this review was to compare these differences, comment on recent studies and evidence gaps, propose a more pragmatic algorithm combining all current indications, and highlight important research directions for this disease that has dominated already the cardiovascular landscape for more than five decades, but for which there have been no significant recent changes in management.

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.

Apixaban and Valve Thrombosis After Transcatheter Aortic Valve Replacement: The ATLANTIS-4D-CT Randomized Clinical Trial Substudy

BACKGROUND

Subclinical obstructive valve thrombosis after transcatheter aortic valve replacement (TAVR) is of uncertain frequency and clinical impact.

OBJECTIVES

The aim of this study was to determine the effects of apixaban vs standard of care on post-TAVR valve thrombosis detected by 4-dimensional (4D) computed tomography.

METHODS

The randomized ATLANTIS (Anti-Thrombotic Strategy to Lower All Cardiovascular and Neurologic Ischemic and Hemorrhagic Events After Trans-Aortic Valve Implantation for Aortic Stenosis) trial demonstrated that apixaban 5 mg twice daily was not superior to standard of care (vitamin K antagonists or antiplatelet therapy) after successful TAVR and was associated with similar safety but with more noncardiovascular deaths. Three months after randomization, 4D computed tomography was proposed to all patients to determine the percentage of patients with ≥1 prosthetic valve leaflet with grade 3 or 4 reduced leaflet motion or grade 3 or 4 hypoattenuated leaflet thickening (the primary endpoint) in the intention-to-treat population.

RESULTS

Seven hundred sixty-two participants had complete multiphase datasets and were included in the 4D computed tomographic analysis. The primary endpoint occurred in 33 (8.9%) and 51 (13.0%) patients in the apixaban and standard-of-care groups, respectively. It was reduced with apixaban vs antiplatelet therapy (OR: 0.51; 95% CI: 0.30-0.86) but not vs vitamin K antagonists (OR: 1.80; 95% CI: 0.62-5.25) (P_interaction = 0.037). The composite of death, myocardial infarction, any stroke, or systemic embolism at 1 year occurred in 10.7% (n = 9 of 84) and 7.1% (n = 48 of 178) of patients with and without subclinical valve thrombosis at 90 days, respectively (HR: 1.68; 95% CI: 0.82-3.44).

CONCLUSIONS

Apixaban reduced subclinical obstructive valve thrombosis in the majority of patients who underwent TAVR without having an established indication for anticoagulation. This study was not powered for clinical outcomes. (Anti-Thrombotic Strategy After Trans-Aortic Valve Implantation for Aortic Stenosis [ATLANTIS]; NCT02664649).

Subclinical Leaflet Thrombosis After Transcatheter Aortic Valve Replacement: A Meta-Analysis

This meta-analysis and systematic review was performed to evaluate the clinical relevance of subclinical leaflet thrombosis (SLT) following transcatheter aortic valve replacement. PubMed, Web of Science, and CENTRAL were searched for eligible randomized and nonrandomized studies until November 2020. Risk ratios (RRs) or odds ratios and 95% CIs were calculated, using a random-effects model. Overall, 25 studies were eligible for the analysis and comprised a total of 11,098 patients. The median incidence of SLT was 6% at a median follow-up of 30 days. Use of intra-annular valves was associated with 2-fold greater risk for the development of SLT compared with use of supra-annular valves. There was no difference in the risk for SLT (RR: 0.97; 95% CI: 0.72-1.29; P = 0.83) between single-antiplatelet therapy (SAPT) and dual-antiplatelet therapy (DAPT), whereas oral anticoagulation (OAC) was associated with a 58% relative risk reduction for SLT (RR: 0.42; 95% CI: 0.29-0.61; P < 0.00001) compared with SAPT and DAPT. In patients with diagnosed leaflet thrombosis at follow-up, the risk for stroke or transient ischemic attack was increased by 2.6-fold (RR: 2.56; 95% CI: 1.60-4.09; P < 0.00001) compared with patients without leaflet thrombosis. In patients diagnosed with SLT, the odds of SLT resolution increased by 99% after switch from antiplatelet agents to OAC (odds ratio: 0.01; 95% CI: 0.00-0.06; P < 0.00001). To summarize, indication-based use of OAC after transcatheter aortic valve replacement is associated with a lower risk for SLT compared with SAPT and DAPT. Switching to OAC seems to be effective for SLT resolution. As SLT increased the odds of stroke or transient ischemic attack in the included population, further studies are needed to investigate whether screening tests for SLT and appropriate antithrombotic therapy improve long-term valve functionality and clinical prognosis.

Management of Life-Threatening Bleeding in Patients With Mechanical Heart Valves

Valvular heart disease is common in the United States, with a number of patients undergoing valve replacement procedures every year. The two types of valve prostheses include mechanical and bioprosthetic valves. Mechanical heart valves require lifelong anticoagulation with vitamin K antagonists like warfarin. The clinicians are often faced with the dilemma of major bleeding episodes such as intracranial hemorrhage or gastrointestinal bleeding in these patients. The management includes reversing warfarin-induced coagulopathy with vitamin K supplementation, fresh frozen plasma, or prothrombin complex concentrate (PCC), with PCC being the treatment of choice. With regard to the safe resumption of anticoagulation, guidelines are silent, and data is limited to case reports/series. This article reviews the present literature for the management of bleeding in patients with mechanical heart valves and the safe duration for holding off anticoagulation with minimal risk of valve thrombosis/thromboembolism.

Current Devices and Complications Related to Transcatheter Mitral Valve Replacement: The Bumpy Road to the Top

Mitral regurgitation is the most common valvular lesion in the developed world, with increasing prevalence, morbidity, and mortality. The experience with surgical mitral valve repair or replacement is very well-validated. However, more than 45% of these patients get denied surgery due to an elevated risk profile and advanced disease of the left ventricle at the time of presentation, promoting the need for less invasive transcatheter options such as transcatheter repair and transcatheter mitral valve replacement (TMVR). Early available TMVR studies have shown promising results, and several dedicated devices are under clinical evaluation. However, TMVR is still in the early developmental stages and is associated with a non-negligible risk of periprocedural and post-procedural complications. In this review, we discuss the current challenges facing TMVR and the potential TMVR-related complications, offering an overview on the measures implemented to mitigate these complications, and future implications.

Increased utilization of bioprosthetic aortic valve technology:Trends, drivers, controversies and future directions

Introduction: Bioprosthetic valves (BPV) implanted surgically or by transcatheter valve implantation (TAVI) comprise an overwhelming majority of substitute aortic valves implanted worldwide.Areas Covered: Prominent drivers of this trend are: 1) BPV patients have generally better outcomes than those with a mechanical valve, and remain largely free of anticoagulation and its consequences; 2) BPV durability has improved over the years; and 3) the expanding use of TAVI and valve-in-valve (VIV) procedures permitting interventional management of structural valve degeneration (SVD). Nevertheless, key controversies exist: 1) optimal anticoagulation regimens for surgical and TAVI BPVs; 2) the incidence, mechanisms and mitigation strategies for SVD; 3) the use of VIV for treatment of SVD, and 4) valve selection recommendations for difficult cohorts, (e.g. patients 50-70 years, patients <50, childbearing age women). This communication reviews trends in and drivers of BPV utilization, current controversies, and future directions affecting BPV use.Expert Opinion: Long-term data are needed in several areas related to aortic BPV use, including anticoagulation/antiplatelet therapy, especially following TAVI. TAVI and especially VIV durability and optimal use warrant will benefit greatly from long-term data. Certain populations may benefit from such high-quality data on multi-year outcomes, particularly younger patients.

Safety and efficacy of repeat transcatheter aortic valve replacement for the treatment of transcatheter prosthesis dysfunction

Introduction: Transcatheter aortic valve replacement (TAVR) has recently expanded toward the treatment of younger patients with lower surgical risk and longer life expectancy. Thus, transcatheter heart valve (THV) durability has become a central issue, and an important increase in the number of TAVR-in-TAVR is expected in the coming years. Areas covered: Overview of the current status of TAVR-in-TAVR for the treatment of THV dysfunction, focusing on safety and efficacy of repeat TAVR procedures. Expert opinion: An accurate analysis of the pre-procedure cardiac computed tomography, incorporating new parameters such as the position of the top of the first THV in relation to the sinotubular-junction, will be necessary to assess the risk of coronary occlusion. Subsequent coronary angiography will be necessary in a proportion of TAVR-in-TAVR patients, but coronary access may be very difficult or even impossible in some of them. Therefore, the choice between TAVR and SAVR in young low-risk patients should incorporate the potential need for treating coronary events at mid- to long-term follow-up. Likewise, the choice of the valve type and the implantation position at the time of the first TAVR procedure should take into account the possibility of TAVR-in-TAVR in the future.Abbreviations ACS: acute coronary syndrome; CO: coronary obstruction; EOA: effective orifice area; SAVR: surgical aortic valve replacement; SVD: structural valve degenerationTAVR: transcatheter aortic valve replacement; THV: transcatheter heart valve.

Anticoagulation Resumption in a Patient With Mechanical Heart Valves, Antithrombin Deficiency, and Hemorrhagic Transformation Following Thrombectomy After Ischemic Stroke

Anticoagulation is essential for patients undergoing mechanical heart valve replacement; however, the timing to reinitiate the anticoagulant could be a dilemma that imposes increased risk for bleeding events in patients suffering from the life-threatening hemorrhagic transformation (HT) after ischemic stroke. Such a situation was presented in this case report. A 71-year-old woman was transferred directly to the Neurocritical Care Unit because of a HT that occurred following the mechanical thrombectomy for ischemic stroke. Since she had a history of prosthetic metallic valve replacement, how the anticoagulating therapy could balance the hemorrhagic and thrombotic risks was carefully evaluated. On day 6 after the onset of hemorrhage transformation, the laboratory results of coagulation and fibrinolysis strongly suggested thrombosis as well as antithrombin deficiency. The short-acting and titratable anticoagulant argatroban was immediately initiated at low dose, and thrombosis was temporarily terminated. On day 3 of anticoagulation resumption, argatroban was discontinued for one dose when the prothrombin time and activated partial thromboplastin time significantly prolonged after argatroban infusion. Aortic valve thrombosis was detected the next day. The anticoagulation was then strengthened by dose adjustment to keep mitral valve intact, to stabilize the aortic valve thrombosis, and to decrease the aortic flow rate. The intravenous argatroban was transited to oral warfarin before the patient was discharged. This study is the first report of administering argatroban and titrating to its appropriate dose in the patient with valve thrombosis, antithrombin deficiency, and HT after mechanical thrombectomy for acute ischemic stroke. Notably, the fluctuations argatroban brings to the coagulation test results might not be interpreted as increased bleeding risk. This case also suggested that the reported timing (day 6 to day 14 after hemorrhage) of anticoagulant resumption in primary intracerebral hemorrhage with mechanical valves might be late for some patients with HT.

Reversal of Bioprosthetic Aortic Valve Thrombosis Using Rivaroxaban-A Case Report

Background: Bioprosthetic valve thrombosis (BPVT) is a rare but recognized complication causing valve dysfunction. In subacute valve thrombosis, systemic oral anticoagulation is recommended. However, there is little data comparing the efficacy of warfarin and novel oral anticoagulant (NOAC) therapy in this setting.

Case Summary: A patient developed subacute BPVT 11 years post-implantation. The patient was initially treated with warfarin for a period of 6 months, with limited effect. Following replacement of warfarin with rivaroxaban, there was significant reversal of the BPVT, as represented by a reduction in transaortic maximal velocity (Vmax) from 4.1 to 3 m/s over 7 months.

Discussion: Systemic oral anticoagulation can be an effective treatment for subacute valve thrombosis. Guidelines currently recommend warfarin as first line but NOACs can be considered in such patients and may be more effective than warfarin. Randomized controlled trials are required to further establish the optimal anticoagulation for patients with subacute BPVT.

Mechanical Valve Thrombosis in a Pregnant Patient: A Case of Therapeutic Failure

Mechanical valve thrombosis is life-threatening complication especially in pregnant patients. The optimal anticoagulation regimen is still not certain as there are different fetal and maternal risks associated with anticoagulation. A 37-year-old woman with a history of rheumatic heart disease with a mechanical mitral valve replacement 13 years prior presented to the hospital with dyspnea on mild exertion associated with orthopnea for three days. She was nine weeks pregnant, she had been on warfarin prior to pregnancy, and was switched to low molecular weight heparin (LMWH) in her 6th week of pregnancy. Fluoroscopy showed that one leaflet of the mitral valve was nearly fixed, while the other leaflet had restricted motion at maximal opening. Transesophageal echocardiogram (TEE) showed a very large thrombus approximately 3-4 cm² encompassing the entire mechanical valve with one immobile leaflet and limited mobility in other leaflet. In view of her clinical status (dyspnea with NYHA Class IV symptoms), the patient underwent uncomplicated bioprosthetic mitral valve replacement. However, the fetus did not survive. Mechanical heart valve (MHV) thrombosis is life-threatening complication in pregnancy. The optimal anticoagulation therapy in pregnancy is unclear. This case report brings into light that in spite of adequate anticoagulation, pregnant patients with mechanical heart valves are still at a high risk of developing valve thrombosis. It highlights the use of transthoracic and transesophageal echocardiogram along with fluoroscopy in diagnosing this and discusses the therapeutic options for this unique condition.

A Novel Sensorized Heart Valve Prosthesis: Preliminary In Vitro Evaluation

Background: Recent studies have shown that subclinical valve thrombosis in heart valve prosthesis (HVP) can be responsible for reduced leaflet motion detectable only by advanced imaging diagnostics. We conceived a novel sensorized HVP able to detect earlier any thrombus formation that may alter the leaflets motion using an electric impedance measurement, IntraValvular Impedance (IVI). Methods: For IVI measurement, dedicated electrodes are embedded in the structure of the HVP to generate a local electric field that is altered by the moving valve leaflets during their cyclic opening/closing. We present preliminary in vitro results using a first prototype of sensorized mechanical heart valve connected to an external impedance measurement system. The prototype was tested on a circulatory mock loop system and the IVI signals were recorded during both normal dynamics and experimentally induced altered working of the leaflets. Results: Recordings showed a very repetitive and stable IVI signal during the normal cyclic opening/closing of the HVP. The induced alterations in leaflet motion were reflected in the IVI signal. Conclusions: The novel sensorized HVP has great potential to give early warning of possible subclinical valve thrombosis altering the valve leaflet motion, and to help in tailoring the anticoagulation therapy.

Prosthetic Tricuspid Valve Thrombosis

Prosthetic valve thrombosis, a serious complication of prosthetic valve replacement, can be lethal without proper treatment. Right-sided valve thrombosis is rare but several therapeutic modalities can be considered: anticoagulation therapy, fibrinolysis, or surgery. Here, we report a case of significant tricuspid valve thrombosis which failed fibrinolytic therapy requiring repeat sternotomy with repeat tricuspid valve replacement with a porcine bioprosthesis.

Comparison of dual antiplatelet therapy versus oral anticoagulation following transcatheter aortic valve replacement: A retrospective single-center registry analysis

BACKGROUND

The choice of optimal antithrombotic regimen after transcatheter aortic valve replace-ment (TAVR) remains a matter of debate. The objective of this study was to compare both efficacy and safety outcomes based on the type of antithrombotic therapy prescribed after TAVR Methods: This is a retrospective analysis of 514 consecutive patients treated with either dual antiplate¬let therapy (DAPT) (n = 315; 61.3%) or oral anticoagulation (OAC) plus clopidogrel (n = 199; 38.7%) for a minimum of 3 months after TAVR followed by antiplatelet monotherapy or OAC only, respectively. Patients had pre-defined clinical and echocardiographic follow-ups at 30 days, 6 and 12 months. The key efficacy endpoint was a composite of all-cause death, myocardial infarction, stroke and valve throm¬bosis at 1 year. The key safety endpoint was the occurrence of life-threatening/major bleeding at 1 year.

RESULTS

Baseline characteristics did not differ between both groups, except for a higher incidence of atrial fibrillation in the OAC group. No significant differences in both efficacy and safety endpoints were observed at 30 days and 6 months. At 1 year, the key efficacy endpoint occurred in 21.5% of the DAPT group compared to 19.7% of the OAC group (p = 0.61). The key safety endpoint occurred in 25.1% and 27.8%, respectively (p = 0.53). However, after 1 year valve thrombosis was reported in 8 (2.5%) patients in the DAPT group but not in the OAC group (p = 0.02).

CONCLUSIONS

OAC after TAVR seems to reduce the risk of clinical valve thrombosis without a statisti-cally significant increase in bleeding complications.

Thrombotic valvular dysfunction with transcatheter mitral interventions for postsurgical failures

BACKGROUND

Degenerated surgical mitral valve repairs or surgical prostheses are currently being treated with transcatheter mitral valve replacement (TMVR). We report the procedural and mid-term assessment of thirteen cases.

METHODS

From 12/2013 to 12/2015, 13 consecutive patients with degenerated mitral valve repair or valve replacement were treated. Patients were assessed for mitral valve academic valve consortium (MVARC) defined outcomes.

RESULTS

Immediate procedural MVARC defined technical success was 92%. At 30 days MVARC device and procedure success were 61% and 84%, respectively. Mean follow-up was 150 days [IQR 40-123 days]. There were 2 late major adverse outcomes, a noncardiac related death (628 days) and a stroke (382 days). The mean mitral gradient decreased from 9.5 ± 3.4 to 5.5 ± 2.6 mm Hg (P < 0.01). Three patients were found to have high gradients, two presented with heart failure while another patient was found to have reduced leaflet motion and abnormal thickening postprocedure. The two patients with heart failure were treated with enoxaparin, which caused subsequent resolution of increased valve gradients in one patient. The other patient could not tolerate prolonged treatment from anticoagulation due to gastrointestinal bleeding. Three of 13 patients were treated with dual-antiplatelet therapy and were suspected to have valve thrombosis.

CONCLUSION

Thrombotic related dysfunction post-TMVR occurred in 15% (2/13) of patients and one patient had abnormal leaflet thickening that may have been thrombus related. Dual-antiplatelet therapy was used in all 3 cases suggesting the possible need for oral anticoagulation postmitral valve-in-valve therapy. © 2017 Wiley Periodicals, Inc.