Abstract
Cardiac involvement of hydatid cysts is rare. Hydatidosis of the valvular apparatus can be treated successfully by the careful application of valvular surgical procedures.
To the best of our knowledge, cardiac hydatidosis confined to the anterolateral papillary muscle has not been reported. Herein, we present a case involving a hydatid cyst that was located in a cardiac papillary muscle and that caused mitral regurgitation in a 37-year-old woman. The cyst was removed by papillary muscle incision, and the mitral valve was repaired. The patient experienced an uneventful recovery.
Key words: Cardiac surgical procedures, echinococcosis/diagnosis/pathology/physiopathology/surgery, echocardiography, heart diseases/parasitology/physiopathology, mitral valve/surgery, treatment outcome
Hydatid disease remains a substantial health problem in some areas of the world. Cardiac involvement of hydatid cysts is rare. Here, we present what we believe to be the 1st report of a cardiac hydatid cyst that was completely confined to the anterolateral papillary muscle, and we discuss our surgical treatment of the patient.
Case Report
In June 2007, a 37-year-old woman presented at another hospital with prolonged influenza-like symptoms and diarrhea. Chest radiography revealed a cystic mass in the right lung. The patient was referred to our hospital. Physical examination revealed nothing unusual, other than a mild systolic murmur that was best heard at the cardiac apex. Electrocardiography showed sinus rhythm and no abnormality. Total-body computed tomography showed possible hydatid cysts in the patient's liver, spleen, right lung, and heart. Thoracoabdominal magnetic resonance imaging also indicated that these lesions were very likely of hydatid origin (Fig. 1). Transesophageal echocardiography (TEE) revealed a cystic mass (dimensions, 1.8 × 1.5 cm) in the anterolateral papillary muscle. There was no mitral valve regurgitation. The patient underwent a laparotomy and removal of the cysts in the liver and spleen. Histopathologic examination confirmed the diagnosis of hydatidosis. She was prescribed oral albendazole and was scheduled for follow-up echocardiography 10 weeks later.
Fig. 1. Magnetic resonance image (sagittal plane) shows the heart. The cardiac hydatid cyst (arrow) is in the left ventricular cavity below the mitral orifice.
Upon follow-up, the cystic mass in the papillary muscle had enlarged to 2.8 × 1.9 cm, and moderate-to-severe mitral regurgitation had developed (Fig. 2). The patient was scheduled for surgery.
Fig. 2. Transesophageal echocardiography shows the left ventricular cavity and the mitral orifice in diastole. The anterolateral papillary muscle that contains the hydatid cyst can be seen below the posterior leaflet of the mitral valve.
Surgical Technique
After median sternotomy, heparinization, and ascending-aortic and bicaval cannulation were performed, cardiopulmonary bypass was instituted. The posterior wall of the left ventricle was inspected externally. There was no extension of the cyst. After the aorta was cross-clamped, the mitral valve was exposed through a standard left atriotomy. The anterolateral papillary muscle was diffusely enlarged and had a whitish appearance at its tip (Fig. 3). Iodine-soaked sponges were placed around the muscle in order to prevent possible seeding from cystic rupture. The muscle was incised at its medial aspect. The hydatid cyst, which contained membranes and daughter vesicles, was removed. The remaining cavity was left open. The cyst did not involve the ventricular wall and was completely confined to the papillary muscle. Posterior leaflet prolapse and tissue deficiency between the P1 and P2 scallops were repaired by means of quadrangular resection. A 26-mm annuloplasty ring was implanted. The patient was weaned from cardiopulmonary bypass. Intraoperative TEE showed that the mitral valve had become competent. Thoracic surgeons then removed a cyst from the right lung. Histopathologic examination of both cysts confirmed the diagnosis of hydatidosis. The patient had an uneventful recovery and was discharged from the hospital with instructions to take albendazole for the rest of her life. She remained in good health 12 months postoperatively.
Fig. 3. Intraoperative photographs show the mitral valve orifice. The papillary muscle (A) was pulled out through the mitral annulus (B). Note the enlargement and whitish appearance of the tip of the papillary muscle (arrow).
Discussion
Hydatid disease is caused by the parasite Echinococcus granulosus, which forms cysts. Due to entrapment of the parasite embryo by the portal or pulmonary circulation, the liver and the lungs are typical locations of the cysts. Rarely, the parasite reaches the systemic circulation, and it can then infest any organ.
Cardiac cysts are seen in approximately 0.5% to 2% of all cases of human hydatidosis.1 The interventricular septum and the left ventricular free wall are the most common locations.2 In a report of a septal location,3 a hydatid cyst that adhered to a papillary muscle and to the chordae tendineae required removal via ventricular septal defect closure and valvular repair. A case was reported of a right ventricular hydatid cyst that invaded the posterior papillary muscle of the tricuspid valve. The surgical treatment of that patient included papillary muscle resection and tricuspid valve replacement.4
When hydatid cysts rupture into the cardiac chambers (especially into the right heart), the natural history is metastasis. Seeding during surgery may cause recurrence. Hydatid cyst surgery is actually induced rupture under controlled conditions. Before entering a cyst, it is the usual practice to inject scolicidal agents into it in an attempt to kill daughter vesicles, and then to cover the operative field with agent-soaked gauze.5 Common scolicidal agents are solutions of hypertonic saline (10%–20%), chlorhexidine, alcohol (80%), silver nitrate (5%), and iodine (1%). There is no consensus regarding which agents to use or how effective they are.6
Our patient's case was unique in that her cardiac cyst was confined to the papillary muscle. This suggests that the embryo reached this location hematogenously through the central artery of the papillary muscle—a theory that is supported by a previous report.7 Our patient's mitral valve regurgitation can be explained by the posterior leaflet prolapse that resulted from the enlargement and elongation of the anterolateral papillary muscle.
Hydatidosis of the valvular apparatus can be treated successfully by careful application of valvular surgical procedures. Close follow-up is warranted in order to detect possible recurrence at an early stage.
Footnotes
Address for reprints: Anil Z. Apaydin, MD, Department of Cardiovascular Surgery, Ege University Medical School, 35100 Izmir, Turkey
E-mail: anil.apaydin@ege.edu.tr
References
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