Prosthetic Valve Thrombosis — Urgent Surgery or Thrombolysis?

Abstract & Commentary

By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San FranciscoDr. Boyle reports no financial relationship relevant to this field of study.

Source: Keulerrs S, et al. Comparison of thrombolysis versus surgery as a first line therapy for prosthetic heart valve thrombosis. Am J Cardiol. 2011;107:275-279.

Thrombosis of prosthetic heart valves is one of the most feared complications of heart-valve replacement. Thrombolysis and emergency surgery are two therapeutic options for prosthetic valve thrombosis (PVT), each receiving a class II recommendation in the AHA/ACC guidelines. However, there are little data comparing these two options. Accordingly, Keuleers and colleagues retrospectively evaluated their center's experience of patients presenting with PVT over 20 years.

They identified 31 patients with PVT causing valvular obstruction. In 30 patients, this involved a mechanical valve; in the other patient, it was a bioprosthesis. The treating physician made the choice for thrombolysis vs. surgery. Success of thrombolysis was defined as complete, partial, or failure, depending on the degree of clinical improvement and the resolution of the valve leaflet obstruction. The majority of cases involved the mitral valve (n = 17), eight involved the aortic valve, and six involved the tricuspid valve.

Most patients (90%) presented with dyspnea, 42% had NYHA class IV symptoms, 33% had hemodynamic compromise on admission, and 13% presented with systemic embolization. In the majority of patients (61%), symptoms started more than 1 week prior to presentation. Importantly, sub-therapeutic international normalized ratio (INR) was present in 15 of 31 patients (48%); in nine patients, a temporary cessation of anti-coagulation within 2 months had preceded the event.

Results: Thirteen patients were treated with thrombolysis; all received rtPA with unfractionated heparin. There was immediate clinical improvement in 92%; 62% showed complete resolution and 31% showed partial resolution of echocardiographic changes. The one patient who failed thrombolysis was referred for urgent surgery. However, complications were relatively common. Recurrent PVT was seen in four patients (31%) over the following 18 months. Furthermore, stroke occurred in one patient (8%), TIA in 8%, major hemorrhage requiring surgery in 8%, and peripheral emboli in 15%.

Eighteen patients underwent immediate surgery, with two peri-operative deaths (11%) and two recurrences of PVT (11%) over a median follow-up of 76 months. Surgical patients also experienced significant complications, including acquired ventricular septal defect (n = 1), sepsis and sternitis with ICU stay > 1 month (n = 2), the need for a permanent pacemaker (n = 1), and the need for repeat surgery (n = 1). The authors conclude that thrombolysis is an attractive first-line therapy for patients with PVT, with clinical outcomes comparing favorably with the standard surgical approach.

Commentary

The morbidity and mortality from PVT are high, and clinicians must have a high index of suspicion for this condition. It is interesting to note that the majority of patients had symptoms for over 1 week prior to presentation, and many of these had documented sub-therapeutic INR values or interruption of anti-coagulant therapy. Patients with a prosthetic valve presenting with dyspnea, especially if anticoagulation has been sub-optimal, should be carefully evaluated for PVT.

Whereas surgery has been the traditional treatment for this condition, several series have now demonstrated that thrombolysis may be an effective alternative. However, it is important to note the high rate of complications with either option. This study is limited by its small sample size and retrospective observational nature; however, the results are congruent with other series. In the absence of randomized, controlled trial evidence to support one treatment over the other, the best option, when confronted with PVT, appears to be a careful evaluation of the individual patient, with consideration of the risks of thrombolysis or surgery in that patient.