Longest Event-Free Survival without Anticoagulation in a Mechanical Aortic Valve Replacement

Anticoagulation for Mechanical Aortic Valve in a Patient With Aortic Dissection and Pulmonary Hemorrhage: A Case Report

Acute aortic dissections are considered surgical emergencies because they are catastrophic bleeding events. The risk of bleeding is further increased if the patient requires anticoagulation for other comorbidities, such as a mechanical heart valve.  This case study describes a 73-year-old gentleman who presented with massive hemoptysis due to an acute aortic dissection complicated by pulmonary hemorrhage in the context of previous aortic dissection with multiple repair surgeries and residual chronic aortic dissection. He was also on warfarin for a mechanical aortic valve complicated by supratherapeutic international normalized ratio. His acute aortic dissection was treated conservatively without surgery, and he survived. Concerning the risk of thromboembolism from the mechanical aortic valve, anticoagulation was reintroduced one week after his initial bleeding. We changed warfarin to enoxaparin, which was started at a small dose, 40 mg subcutaneously once a day, then gradually increased to the full therapeutic dose, 90 mg (1 mg/kg) twice daily over a week. He was not fully anticoagulated for two weeks. Fortunately, he did not develop any thrombosis. Hemoglobin and Factor Xa levels were closely monitored. He tolerated the enoxaparin without further bleeding.  This type of case is rare and has not been previously reported, considering the patient survived acute aortic dissection with conservative management, did not develop any thrombosis from the mechanical aortic valve when anticoagulation was withheld, and did not experience rebleeding when anticoagulation was restarted. Further research and guidelines are needed to assist clinicians in managing anticoagulation when facing the dilemmas of the risk of bleeding and the risk of thromboembolism. This is particularly important in complex scenarios, such as for patients with mechanical heart valves who subsequently develop contraindications such as aortic dissection or other life-threatening bleeding events.

Challenges Faced and Lessons Learned: The Journey of a 22-Year-Old Male with a Mechanical Heart Valve Complicated by Ischemic Stroke in a Developing Country: A Sub-Saharan Africa Prospect

This report reviews an Ethiopian patient who underwent cardiac surgery and had a mechanical heart valve implanted on the mitral valve with tricuspid valve repair for rheumatic heart disease via a local non-profit organization donation later complicated by cardio-embolic stroke, and aims to describe the challenges faced by patients from rural Ethiopia who require cardiac surgery for rheumatic heart disease and narrate the importance of careful follow-up. The lessons to be drawn from this case are that careful follow-up and adherence to prescribed Vitamin K antagonists after surgery for mechanical heart valves are critical and, when such patients are lost to follow-up as was witnessed in this case, it can induce lifelong morbidity. Morbidity that could have been avoided with strict and meticulous follow-up and with standardized patient tracing or contact systems. When patients are lost to follow-up it needs to be top priority to trace them after cardiac surgery and this report highlights the pivotal role of the health education in such populations. Unless we utilize this opportunity to unlock the door and embrace a systemic approach to reforming our risk assessment, referral chain system, and integration of various healthcare professionals in patient follow-up, as well as enhancing health education among our patients in rural Ethiopia and other low-income countries, the consequences could prove to be significant. Preventing such fatal complications is far superior to managing them afterwards, as it not only saves on expenses but also saves lives and enhances quality-of-life.

TAVR for All? The Surgical Perspective

In spite of the noninferiority of transcatheter aortic valve replacement (TAVR) in high- and intermediate-risk patients, there are still obstacles that need to be overcome before the procedure is further expanded and clinically integrated. The lack of evidence on the long-term durability of the bioprostheses used for TAVR remains of particular concern. In addition, surgery may be preferred over TAVR in patients with bicuspid aortic valve (BAV) or with concomitant pathologies such as other valve diseases (mitral regurgitation/tricuspid regurgitation), aortopathy, and coronary artery disease. In this review, we discuss and summarize relevant data from clinical trials, current trends, and remaining obstacles, and provide our perspective on the indications for the expansion of TAVR.

New warfarin anticoagulation management model after heart valve surgery: rationale and design of a prospective, multicentre, randomised trial to compare an internet-based warfarin anticoagulation management model with the traditional warfarin management model

INTRODUCTION

Warfarin is an effective anticoagulant and the only oral anticoagulant available for patients with mechanical heart valves. The prothrombin time and the associated international normalised ratio (INR) are routinely tested to monitor the response to anticoagulation therapy in patients. Patients who undergo mechanical heart valve replacement need lifelong anticoagulation therapy, and their INR is regularly measured to adjust the anticoagulation strength and the dose of anticoagulation drugs. Appropriate warfarin anticoagulation management can reduce patient complications, such as bleeding and thrombosis, and improve the long-term survival rate. We propose modern internet technology as a platform to build a warfarin anticoagulation follow-up system after valve replacement surgery. This system will provide doctors and patients with more standardised and safer follow-up methods as well as a method to further reduce the risk of warfarin anticoagulation-related complications and improve its therapeutic effects.

METHODS AND ANALYSIS

A prospective, multicentre, randomised, controlled trial will be conducted. A total of 700 patients who require long-term warfarin anticoagulation monitoring after heart valve replacement will be enrolled and randomly divided at a 1:1 ratio into a traditional outpatient anticoagulation management group and a group undergoing a new method of management based on the internet technology with follow-up for 1 year. Differences in the percentage of time in the therapeutic range (TTR), drug dose adjustments, bleeding/thrombosis and other related complications will be observed. The primary endpoint is the difference in the TTR between the two groups. The purpose of this study is to explore a safer and more effective mode of doctor-patient interaction and communication in the internet era. As of 13 July 2019, 534 patients had been enrolled.

ETHICS AND DISSEMINATION

This study protocol was approved by the Ethics Committee of Beijing Anzhen Hospital, Capital Medical University. The results will be published in a peer-reviewed medical journal.

TRIAL REGISTRATION NUMBER

ChiCTR1800016204.

Short-term evaluation of thromboresistance of a poly(ether ether ketone) (PEEK) mechanical heart valve with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted surface in a porcine aortic valve replacement model

Improved thromboresistance of mechanical valves is desired to decrease the risk of thromboembolism and thrombosis and reduce the dosage of anticoagulation with a vitamin K antagonist (e.g., warfarin). For several mechanical valves, design-related features are responsible for their improved thromboresistance. However, it remains unclear whether material-related features provide a practical level of thromboresistance to mechanical valves. Here, we studied the effect of a bileaflet valve made of poly(ether ether ketone) (PEEK) with a poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted surface (PEEK-g-PMPC). PMPC is a well-known thromboresistant polymeric material. A short-term (<26 h) porcine aortic valve replacement model using neither an anticoagulant nor an antiplatelet agent showed that the PEEK-g-PMPC valve opened and closed normally with an allowable transvalvular gradient. Unlike an untreated PEEK valve, no thrombus formed on the PEEK-g-PMPC valves on gross anatomy examination in addition to the absence of traveled thrombi in the kidney and lung tissues. Material (PEEK-g-PMPC)-related thromboresistance appeared to decrease the risk of thromboembolism and thrombosis for patients with mechanical valves. However, thromboresistance of the PEEK-g-PMPC valve requires improvement because fibrous fouling was still observed on the leaflet. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1052-1063, 2019.