Increased sensitivity to warfarin after heart valve replacement.

Background: The dosage requirement of warfarin to achieve a given international normalized ratio (INR) often varies considerably between the immediate postoperative period and long-term follow-up in patients with prosthetic heart valves, leading to INR instability.

Objective: To document the extent of warfarin sensitivity in a prospective study of patients receiving heart valve replacements.

Methods: Clinical and laboratory data regarding anticoagulation for 111 patients who received warfarin following heart valve replacement were collected during their hospital stay (induction period) and between 1 and 3 months after surgery (follow-up period).

Transient dynamic mid-left ventricular obstruction following aortic valve replacement.

The case is presented of dynamic left ventricular mid-cavitary obstruction that complicated the postoperative course following aortic valve replacement and coronary artery bypass grafting. The condition resolved with appropriate medical management, without further surgical intervention. It is hypothesized that this was due to both concentric left ventricular hypertrophy and direct diastolic ventricular interaction.