Correspondence

Thrombolytic Therapy for Thrombosis of an Aortic Bioprosthetic Valve

N Engl J Med 1994; 330:1906-1907June 30, 1994

Article

To the Editor:

Acute thrombotic obstruction of an aortic bioprosthetic valve is an uncommon yet life-threatening condition1-3. A 72-year-old man came to our hospital because of four days of chest pain and dyspnea. Seven months earlier, he had undergone an aortic-valve replacement with a 27-mm Medtronic Intact porcine bioprosthesis. The results of cardiac auscultation were compatible with a diagnosis of aortic stenosis. The patient had mild thrombocytopenia (139,000 platelets per cubic millimeter) and an increased lactate dehydrogenase level (571 U per liter). Echocardiography revealed reduced motion of the prosthetic-valve leaflets and an obstructing mass between the struts (Figure 1AFigure 1Transesophageal Echocardiographic View of an Aortic Bioprosthesis with a Thrombotic Mass Visible between the Struts (Panel A, Arrow) and a Similar View 48 Hours after Thrombolysis, Showing the Valve Strut and Valve Orifice Free of Thrombus (Panel B).). Doppler ultrasonography showed a peak instantaneous transprosthetic gradient of 110 mm Hg, which is consistent with prosthetic thrombosis.

Streptokinase (1.5 million U) was infused intravenously over a period of 60 minutes, followed by intravenous administration of heparin sodium at an initial dose of 1000 U per hour and, subsequently, at the dose required to maintain an activated partial-thromboplastin time of two to three times the control value. Concomitantly, warfarin therapy (at a dose of 3 to 6 mg daily) was started. Within a few hours after the start of therapy, the systolic murmur had decreased in intensity. Doppler echocardiography showed normal valve movement, regression of the transprosthetic gradient, and no valvular thrombus (Figure 1B). The platelet count (216,000 per cubic millimeter) and serum lactate dehydrogenase level (441 U per liter) had returned to normal.

The incidence of thrombosis of mechanical prosthetic valves ranges from 0.5 to 6 percent (in the aortic- and mitral-valve positions) to 20 percent (in the tricuspid-valve position) per patient-year1. For bioprostheses, the overall average rate of thrombotic stenosis is 0.03 percent per year1. Heart-valve thrombosis may present insidiously, and recognition of it may be difficult. Cinefluoroscopy and transthoracic and transesophageal Doppler echocardiography are reliable diagnostic methods4. The standard therapy for thrombotic-valve obstruction has been high-risk emergency surgery2. More recently, however, thrombolytic therapy has been recommended3. Thrombolysis may be used to render patients, especially those who are critically ill, stable enough to undergo reoperation when needed. The success rate of thrombolysis ranges from 70 to 85 percent3. Recurrence of thrombosis has been reported in about 20 percent of patients after initial successful treatment3. The risks of fibrinolysis (i.e., bleeding and embolization) are rarely of clinical importance1,4. In addition to hemolysis, activation of the blood-coagulation system and reduced platelet survival have been reported in patients after heart-valve replacement5. In our patient, thrombocytopenia may have been a result of platelet consumption in the process of thrombus formation and platelet destruction due to higher shear stresses. The latter mechanism may be responsible for hemolysis.

Thrombolysis offers an effective and relatively safe nonsurgical treatment for prosthetic-valve thrombosis.

Michaela Diamant, M.D., Ph.D.
Wybren Jaarsma, M.D., Ph.D.
Wim J. Morshuis, M.D., Ph.D.
St. Antonius Hospital, 3430 EM Nieuwegein, the Netherlands

5 References

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Citing Articles (3)

Citing Articles

1. 1

   Nikolaus Jander, Rolf-Peter Kienzle, Gian Kayser, Franz-Josef Neumann, Christa Gohlke-Baerwolf, Jan Minners. (2011) Usefulness of Phenprocoumon for the Treatment of Obstructing Thrombus in Bioprostheses in the Aortic Valve Position. The American Journal of Cardiology
   CrossRef

2. 2

   Morgan L. Brown, Soon J. Park, Thoralf M. Sundt, Hartzell V. Schaff. (2011) Early thrombosis risk in patients with biologic valves in the aortic position. The Journal of Thoracic and Cardiovascular Surgery
   CrossRef

3. 3

   Francesco Patanè, Fabrizio Sansone, Antonio Campanella, Francesco Asteggiano, Mauro Rinaldi. (2009) Acute bioprosthetic thrombosis immediately after aortic valve replacement. Journal of Cardiovascular Medicine 10:2, 167-169
   CrossRef