Peri-operative interruption of anticoagulant treatment in patients with atrial fibrillation and mechanical heart valves (the PIANO study)
04 / 2001 - 04 / 2004
Anticoagulant treatment with vitamin K antagonists is essential in patients with prosthetic heart valves or atrial fibrillation to prevent arterial thromboembolic complications, in particular cerebrovascular infarcts (CVA). However, in case of surgery or other invasive interventions, anticoagulant treatment needs to be interrupted to ensure surgical hemostasis and to prevent excessive peri-operative bleeding. Interruption of anticoagulant treatment is usually achieved by discontinuation of anticoagulants pre-operatively and reinstitution of therapy postoperatively. However, the safety of this strategy (in terms of the peri-operative prevention of arterial thromboembolism) has been poorly documented. Therefore, an alternative strategy may consist of interruption of anti-vitamin K treatment and temporary anticoagulation by means of i.v. heparin, which can be stopped and subsequently re-started few hours pre- and postoperatively. This latter strategy is often applied in patients with prosthetic heart valves, who are thought to be at higher risk for thrombo-embolic events. However, the actual peri-operative risk of thrombo-embolism and long-term outcome in patients with prosthetic heart valves or atrial fibrillation has never been adequately established. Surprisingly, preliminary data indicate that the risk of a peri-operative thrombo-embolic complication in patients with atrial fibrillation is as high as in patients with a prosthetic heart valve. We hypothesise that shortening of the peri-operative interruption of anticoagulation (by means of the temporary use of i.v. heparin) may be effective in the prevention of peri-operative cerebral infarcts in patient with atrial fibrillation or prosthetic heart valves, although part of the beneficial effect may be offset by an increase in bleeding complications. To test this hypothesis the proposed project consists of two parts: First, we intend to perform a prospective randomised study in patients with atrial fibrillation that need to undergo non-cardiac surgery comparing peri-operative interruption of vitamin K antagonists with peri-operative interruption of vitamin K antagonist and temporary institution of intravenous heparin therapy. Primary outcome event in this study will be symptomatic cerebral embolism during 6 months follow-up and asymptomatic cerebral embolism in the two weeks postoperatively. Second, we will perform a retrospective cohort analysis of 1202 consecutive patients who have received a prosthetic heart valve between 1980 and 1995 and from whom the complete long-term follow-up has been recorded in a database. All episodes of non-cardiac surgery in these patients will be analysed. The management of interruption of anticoagulation will be related to the peri-operative and long-term incidence of cerebrovascular events, and other complications. In addition, the analysis will encompass patient-related factors (such as the presence of atrial fibrillation, co-morbidity, etc.). This project may generate clinically applicable results that will be helpful to define the optimal peri-operative anticoagulant regimen in patients with prosthetic heart valves and/or atrial fibrillation.