Routine hospital based follow up for patients with mechanical valve prostheses: is it worthwhile?

Patients who have undergone valve replacement surgery remain at risk of serious and potentially life threatening complications long after their initial surgery. The risk of death from valve related complications has been estimated at approximately 1% per annum. As a consequence lifelong routine follow up of patients with prosthetic heart valves in hospital cardiac clinics is often advocated. 2 However, the precise form that follow up should take and whether continued hospital surveillance influences outcome is unclear. The distinct natural history of bioprosthetic and mechanical valves suggests that the value of routine follow up screening in the two groups may diVer and that for patients with mechanical valves the usefulness of regular hospital visits may be questionable. Late complications of prosthetic valve surgery can be broadly considered in two groups. The first of these relates to the potential for valve thrombosis and arterial thromboembolism, and to the complications of anticoagulant treatment intended to prevent these events. These complications are minimised by optimal monitoring of anticoagulant control. In current practice this is typically undertaken by the general practitioner or in specialised anticoagulant clinics separate from the general cardiology clinic. The second group of complications comprises problems unrelated to anticoagulant control, principally those resulting from the haemodynamic consequences of valve malfunction and the potential for infection. These represent the target of routine hospital surveillance. However, there is little definitive evidence that screening for this group of complications, typically performed on an annual basis, permits more successful intervention than would be aVorded by investigation at the time of symptomatic presentation. Paravalvar leaks in the absence of infection are usually related to technical problems at the time of surgery, and actuarial freedom from paraprosthetic leak exceeds 98% at five years. 4 In contrast to bioprosthetic valves, failure of mechanical valves is rare and usually catastrophic. Despite the uncertain benefits of screening, there are inevitable consequences for resources. In Aberdeen, we evaluated the impact of routine cardiology follow up of patients with mechanical valves, first by a prospective audit of outpatient visits and second by a retrospective review of patients with mechanical prosthetic valves undergoing repeat cardiac surgery.