Cardiovascular Anesthesia: Echo Didactics & Rounds
A 17-yr-old, 56-kg male was referred to our institution with a 2-wk history of left-sided stabbing chest pain, cough, and progressive dyspnea. The patient was initially evaluated in the emergency room of a nearby hospital where chest radiography demonstrated a left-sided chest mass. The patient's medical history was significant for asymptomatic mitral valve prolapse without mitral regurgitation. Diagnostic evaluation included a chest computed tomography (CT) scan with a needle-guided biopsy and a transthoracic echocardiogram. The CT scan results confirmed a highly vascular anterior mediastinal mass measuring 10 cm and compressing the left mainstem bronchus and the pulmonary artery. The biopsy results confirmed a malignant germ-cell tumor. Chemotherapy was initiated, yet the patient's dyspnea increased over 2 days. Transthoracic echocardiogram confirmed compression of the right ventricular outflow tract (RVOT) and main pulmonary artery (maximal systolic dimension was 4 mm with complete diastolic collapse). Peak Doppler velocity through the pulmonary arteries was 3 m/s. A moderately sized apical pericardial effusion was also noted. The patient was urgently taken to the operating room for surgical resection with cardiopulmonary bypass.
Intraoperative transesophageal echocardiography (TEE) examination, performed after median sternotomy, revealed a large mass compressing the RVOT and main pulmonary artery. The largest diameter of the RVOT was 12 mm (Fig. 1A) (video loop; see supplemental data at www.anesthesia-analgesia.org) with a peak Doppler velocity of 1.2 m/s. The pulmonary valve and pulmonary annulus were compressed, resulting in trace pulmonary insufficiency. Concomitant pathology included a pericardial effusion; patent foramen ovale was confirmed by a positive bubble study, buckling of the anterior mitral valve leaflet, and trace mitral regurgitation. After tumor resection, the RVOT appeared normal, measuring 27 mm, with a peak Doppler velocity of 0.8 m/s (Fig. 1B). The pulmonary valve further appeared normal with trivial insufficiency. The patient was discharged 1 wk later with follow-up outpatient chemotherapy scheduled.
Primary pure-cell seminoma (germ-cell tumor) of the mediastinum is a rare and potentially fatal lesion. Encroachment or invasion of adjacent structures is common, as are distant metastasis. Because of its central position within the thorax, the heart can be encroached upon by masses originating in either anterior, posterior, or superior mediastinum (1). Anterior masses tend to compress the right heart chambers; posterior masses impinge on or compress the left atrium or ventricle, particularly the former, because it is the more compliant chamber. TEE and transthoracic echocardiography are useful in making the distinction between compression and encroachment possible. Encroachment does not produce hemodynamic effects, whereas compression results in clinical manifestations similar to pericardial tamponade. Echocardiography is useful in detecting mediastinal masses, the information obtained being complimentary or preliminary to more complete imaging by CT or magnetic resonance imaging scanning (1). In this case, intraoperative TEE provided useful data that included ventricular contractility, the degree of RVOT compression as well as volume status of the right and left ventricles during resection of a mediastinal germ cell tumor.
1. D'Cruz IA, Feghali N, Gross CM. Echocardiographic manifestations of mediastinal masses compressing or encroaching on the heart. Echocardiography 1994;11:523–33.