Thrombotic complications after valve replacement with porcine heterografts

Abstract

The incidence of thrombotic and thromboembolic (TE) complications after Hancock valve replacement was reviewed in 140 patients with mitral valve prostheses and 150 patients with aortic valve prostheses. In patients with aortic valves, 1 embolus occurred and another patient was found at autopsy to have thrombi on a degenerated valve. Both patients had been on aspirin treatment. There was no TE event in patients receiving no anticoagulant therapy. In patients with mitral valves, 16 showed pre‐ and/or postoperative low output syndrome (Group A); 8 of these patients died and 6 had autopsies that showed major thrombi in the heterograft. In 126 long‐term survivors, 9 thromboembolic events occurred (TE incidence 5.4% per patient year). All patients with emboli had atrial fibrillation. The majority (7/9) of emboli occurred during the first 3 postoperative months. Five occurred in patients who were not on anticoagulation (Group B), and 2 occurred in patients receiving warfarin therapy (Group C). There was no thromboembolic event in patients receiving aspirin treatment (Group D). It is concluded that patients with Hancock aortic valves have a very small risk of TE, and do not need anticoagulation. Patients with Hancock mitral valves with stable hemodynamics have a decreased risk of TE and do not require anticoagulation. Patients with atrial fibrillation have an increased risk of TE and should be on warfarin for 3 months after surgery and then on aspirin therapy.

Antithrombotic Therapy in Patients With Mechanical and Biological Prosthetic Heart Valves

“…Other studies have shown that thromboemboli during the first 3 months after operation occurred despite adequate anticoagulation in patients with atrial fibrillation. 39 Those with atrial fibrillation, a history of prior thromboembolism, or thrombi in the left atrium had higher rates of thromboemboli than patients with atrial fibrillation alone. 39…”

Hancock Valve Obstruction In The Mitral Position: Clinical, hemodynamic, and pathological findings

“…One had a cerebral embolism seven days after surgery but recovered well; the other, the subject of this report, developed thrombi later. Eight of 670 patients with late thrombosis were reported by Thiene, et al [1][2][3][4] Five of the eight had thrombi which filled one or more cusp sinuses and impaired cusp excursion; however, only one had clinical signs of prosthetic valve dysfunction. The patients were not given long-term anticoagulant therapy.…”

Anticoagulation or antiplatelet therapy of bioprosthetic heart valves recipients: an unresolved issue

“…Freedom from anticoagulation, therefore, represents the main theoretical advantage of biological, compared with mechanical, aortic prostheses. While a variety of anticoagulant and antiplatelet drug regimens have been described [6][7][8][9][10][11][12][13][14][15][16], a precise antithrombotic protocol for the early postoperative period after bioprosthetic aortic valve replacement (AVR) has not been developed. The 2006 guidelines issued by the American Heart Association (AHA) and the American College of Cardiology (ACC) for valve replacement recommend the prescription of acetyl salicylic acid (ASA) to all recipients of bioprosthetic heart valves (Class I, Level of evidence C) as well as to consider anticoagulating with a vitamin K antagonist (VKA) for 3 months after bioprosthetic AVR, to reach an INR between 2.0 and 3.0, an acceptable alternative but certainly not a primary recommendation (Class IIa, Level of evidence C) [17].…”