Asian Cardiovasc Thorac Ann 2002;10:83-84
© 2002 Asia Publishing EXchange Pte Ltd
Cardiopulmonary Bypass Before General Anesthesia in Prosthetic Valve Thrombosis
Nevzat Erdil, MD,
Levent Çetin, MD,
Vedat Nisanoglu, MD1,
Erol Sener, MD,
Ufuk Demirkiliç, MD
Department of Cardiovascular Surgery Alkan Hospital Ankara, Turkey
1 Department of Cardiovascular Surgery Inönü University Faculty of Medicine Malatya, Turkey
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Nevzat Erdil, MD Tel: 90 422 341 0660 Fax: 90 422 341 0728 email: n_erdil{at}yahoo.com Department of Cardiovascular Surgery, Turgat Özal Medical Center, Inönü University Faculty of Medicine, Elazig Yolu Street, Malatya 44069, Turkey.
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ABSTRACT
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Valve obstruction is a lifethreatening complication of mechanical valve prostheses. Emergency operation is mandatory for patients who subsequently develop cardiogenic shock and severe pulmonary edema. In this severely compromised hemodynamic condition, cardiac arrest develops in most of the patients before surgery and just after general anesthesia induction. In one such case, we performed femorofemoral cardiopulmonary bypass with local anesthesia before general anesthesia induction and successfully replaced the thrombosed prosthetic valve, thus avoiding a catastrophic outcome.
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INTRODUCTION
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Thrombotic obstruction is a rare but often fatal com-plication of cardiac valve prostheses.1 The incidence of this dreaded complication ranges from 1% to 6% in the aortic and mitral valve positions to as high as 20% in the tricuspid position.2 Prosthetic valve thrombosis is still associated with high mortality, even when emergency medical or surgical treatment is promptly established.3 Surgical treatment of disc valve thrombosis includes both thrombectomy and replacement of the prosthetic valve.1 Most of the patients develop cardiovascular collapse during general anesthesia induction or tracheal intubation with high mortality. To avoid this catastrophic outcome in a patient who had developed severe pulmonary edema and cardiogenic shock, we successfully performed emergency replacement of the prosthetic mitral valve by establishing cardiopulmonary bypass (CPB) via the common femoral artery and vein under local anesthesia before general anesthesia was induced.
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CASE REPORT
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A 35-year-old woman underwent mitral valve replacement with a 29-mm Bicarbon bileaflet (Sorin Biomedica, Saluggia, Italy) mechanical valve prosthesis because of significant mitral regurgitation. She was discharged with sinus rhythm and no complications on the 6th postoperative day. Her condition remained normal at 1- and 3-month follow-up, and she was in New York Heart Association functional class I and had an International Normalized Ratio (INR) of 2.3 and 2.1, respectively, during these examinations. Six months after the initial operation, the patient came to our emergency department with sudden onset of dyspnea, orthopnea, and hemoptysis. She had shortness of breath and pulmonary edema with systemic hypotension. No mechanical valve sounds were audible. Immediately, a central venous catheter was placed via the internal jugular vein, and infusions of diuretic and inotropic agents were started. Bedside echocardiography and dynamic fluoroscopy were urgently performed, which revealed no mechanical leaflet movement. One leaflet was completely closed and the other nearly closed. Emergency operation was decided. The period from the patient's arrival at emergency to the operating room was about 45 minutes. The femoral artery and vein were cannulated in the semi-Fowler position under local anesthesia induced by prilocaine hydrochloride (Citanest; Eczacibasi, Istanbul, Turkey). Morphine hydrochloride (Morfin; Galen Medical, Istanbul, Turkey) in a dose of 0.1 mg•kg-1 was used to sedate the patient and to reduce pulmonary edema. The patient was repositioned to supine, and general anesthesia was induced and tracheal intubation performed after initiating CPB. To induce anesthesia and facilitate intubation, 0.1 mg•kg-1 midazolam (Dormicum; Roche, Basel, Switzerland), 0.2 mg•kg-1 etomidate (Hypnomidate; Janssen-Cilag, Istanbul, Turkey), and 0.1 mg•kg-1 pancuronium bromide (Pavulon; Organon Teknika, Istanbul, Turkey) were given. During this period, the patient's systemic arterial pressure fell, but she did not collapse. Transesophageal echocardiography was performed just after tracheal intubation. The prosthetic mitral valve was evaluated in the mid-esophageal view. Both leaflets of the prosthetic valve were not moving. A Swan-Ganz catheter was inserted via the internal jugular vein to measure the pulmonary artery pressure. Her mean pulmonary artery pressure was 42 mm Hg (67/27 mm Hg). After sternotomy, intrapericardial dissection was performed without difficulty. Aortic and bicaval cannulation was performed and the cardiopulmonary circuit changed. The femoral arterial and venous cannulae were canceled. The aorta was crossclamped and the left atrium opened. The bileaflet prosthetic valve was found to be thrombosed and pannus formation extended to both leaflets. The valve was replaced with a 27-mm Sorin mechanical valve prosthesis.
The patient was supported by low-dose infusion of an inotropic agent with aggressive diuresis. Intraaortic balloon pump support was not needed. The patient stayed for 2 days in the intensive care unit without any complications and was discharged uneventfully on the 6th postoperative day. There was no evidence of a sustained stroke or neurocognitive dysfunction. The patient was still alive and in New York Heart Association functional class I a year after reoperation. She had been followed up monthly and had no thromboembolic event in this period. Although she had nearly the same INR as before reoperation, anticoagulation with warfarin sodium and an antiplatelet agent (acetylsalicylic acid, 300 mg/day) was prescribed to maintain an INR between 2 and 3.
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DISCUSSION
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Prosthetic valve obstruction is a relatively rare but serious complication and is the major cause of reoperation for prosthetic valve dysfunction.1 Clinical deterioration is acute and quickly becomes lifethreatening in most cases. General anesthesia may also contribute to hemodynamic collapse in this severely compromised condition by causing myocardial depression, increased pulmonary pressure, generalized or venous vasodilatation, and decreased catecholamine release.4–6 Hence, normal hemodynamic status should be maintained with drugs and/or mechanical support such as CPB.
The early diagnosis and management of prosthetic valve obstruction is therefore extremely important. Trans-esophageal and transthoracic echocardiography and dynamic fluoroscopy are highly valuable methods for rapid management of emergency cases.7 The period between the patient's arrival at emergency and the conduction of femorofemoral bypass under local anesthesia was 60 minutes in our case. Although thrombolytic therapy appears to be an attractive alternative treatment for mechanical valve thrombosis, emergency operation is mandatory for patients who have developed cardiogenic shock and severe pulmonary edema. The operative mortality of patients in severely compromised hemodynamic conditions is still about 20%.8 We performed successful emergency replace-ment of a prosthetic mitral valve in a patient in cardiogenic shock and with pulmonary edema. Our decision for emergency operation was based on the patient's severe clinical condition being caused by an obstructed valve, which was confirmed by echocardiographic and fluoro-scopic examinations. Because most of the patients in such critical conditions develop cardiac arrest before any surgery could be attempted, we decided to start CPB before general anesthesia induction. We believe that establishment of femorofemoral bypass before general anesthesia is a simple, feasible, and reliable method that allows sternotomy to be performed safely and rapidly in these patients.
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ABSTRACT
INTRODUCTION
