Reversing the Tide: A Case of a Mechanical Aortic Valve Recipient Lost to Follow-up, Education on Rivaroxaban Contraindications, and the Vital Role of Acenocoumarol in Preventing Valve Thrombosis

Abstract

Aortic stenosis is the most common heart valve disease, especially among the elderly. Symptomatic aortic valve stenosis is linked to a poor prognosis and a high mortality rate if left untreated. The only effective treatment for severe symptomatic aortic stenosis is aortic valve replacement using either a mechanical or a biological prosthesis. Mechanical valve prostheses, while highly durable, are thrombogenic, necessitating lifelong anticoagulation with oral anti-vitamin K agents, such as acenocoumarol. Conversely, bioprosthetic valves, though less durable, carry a minimal thrombogenic risk and do not require anticoagulation. Currently, there is no proven role for direct-acting oral anticoagulants (DOACs) in patients with mechanical heart valves due to insufficient clinical trial data regarding their safety in this patient population. Herein, we present the case of a 59-year-old female known to have aortic stenosis, who underwent surgical treatment with mechanical aortic valve replacement eight years ago. Post-surgery, acenocoumarol was initiated. However, 18 months prior to presenting at our institution, the patient started taking rivaroxaban (a DOAC) instead of acenocoumarol due to the unavailability of acenocoumarol during the ongoing economic crisis in Lebanon, without consulting her cardiologist. Although she was followed up by her general practitioner and reported having a mechanical valve, her son contradicted this, claiming she had a biological valve. After thorough investigations, including chest X-ray, echocardiography, and fluoroscopy, it was confirmed that the patient indeed had a normally functioning mechanical aortic valve. Immediate corrective measures were taken, starting with IV unfractionated heparin and acenocoumarol, targeting an International Normalized Ratio (INR) between 2.5 and 3, while educating the patient about her condition and the importance of adhering to acenocoumarol therapy.

Keywords: acenocoumarol; aortic stenosis; aortic valve replacement; bioprosthetic aortic valve; mechanical aortic valve prosthesis; mechanical aortic valve thrombosis; oral anti-vitamin k; oral direct anti-coagulant; ribaroxavan; warfarin.