Cardiovascular Anesthesia: Echo Didactics & Rounds
A 42-year-old female patient was referred to our institution with recent progressive dyspnea and fatigue. Her history was significant for 3 previous surgeries for repair of tetralogy of Fallot at age 3, 9, and 17. The patient was informed after the last surgery that she has a persistent left superior vena cava (PLSVC). Diagnostic work-up at our institution with chest wall echocardiogram, magnetic resonance imaging, and cardiac catheterization demonstrated severe pulmonary insufficiency, right ventricular dysfunction, and a patent foramen ovale (PFO). These imaging techniques also confirmed the presence of the PLSVC draining to the coronary sinus (CS). Electrophysiology study identified foci of ventricular tachycardia in the endocardial surface of the right ventricle. The patient was scheduled for an elective pulmonic valve replacement, closure of the PFO, and endocardial ablation for ventricular arrhythmia.
Intraoperative transesophageal echocardiography revealed a normal sized left ventricle and an enlarged right ventricle, both with a good function. The CS was enlarged. The presence of the PLSVC was confirmed by injection of agitated normal saline as echo contrast into the left arm vein. Consistent with the diagnosis of PLSVC, the contrast was seen in the CS instead of draining into the right superior vena cava (Fig. 1) (video loop; see supplemental data at www.anesthesia-analgesia.org). Other pathology confirmed included a PFO with bidirectional shunt and a severely incompetent pulmonic valve. No residual postoperative defects were demonstrated. The patient tolerated the procedure well, and her postoperative course was uncomplicated.
Persistent LSVC, the most common anomaly of systemic venous return, is an uncommon congenital pathology with a prevalence of 0.3–0.5% in patients with normal heart and 1.3–4.5% in patients with congenital heart disease. Tetralogy of Fallot was found in up to 25% of patients with PLSVC (1). A failure of obliteration of the LSVC in late embryologic life results in a PLSVC draining the left upper extremity and left part of the head into the CS and thence into the right atrium, causing a dilation of the CS (2). Usually, a PLSVC, when not associated with other congenital anomalies, is asymptomatic and hemodynamically insignificant. However, PLSVC has important clinical implications. It may complicate placement of cardiac catheters or pacemaker leads and also represents a contraindication for a retrograde administration of cardioplegia. The diagnosis of PLSVC is classically made by injecting contrast into the left upper extremity (e.g., left basilic vein) and demonstrating drainage of the contrast into the CS. The CS on the two-dimensional echocardiography is enlarged (>1 cm in diameter). An enlarged CS can also be found in patients with right ventricular dysfunction and right atrial hypertension. On the basis of the established safety record of the saline microbubble contrast test (3), we felt that it was an acceptable procedure for demonstrating the presence of a PLSVC by echocardiography. To reduce right-to-left shunt we positioned the patient in Trendelenberg position. A PLSVC is a rare anomaly with significant implications for anesthetic management. The case presented will help familiarize anesthesiologists with the typical echocardiographic presentation, diagnostic approach, and clinical consequences.
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2. Gerber TC, Kuzo RS. Images in cardiovascular medicine: persistent left superior vena cava demonstrated with multislice spiral computed tomography. Circulation 2002;105:e79.
3. Nanda NC, Carstensen EL. Echo-enhancing agents: safety. In: Nanda NC Schlief R, Goldberg BB, eds. Advances in echo imaging using contrast enhancers. 2nd ed. Dordrecht, the Netherlands: Kluwer, 1997:115–31.