SESSION TITLE: Procedures Case Report Posters
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM
INTRODUCTION: A 66 year-old man with AL amyloidosis was referred to pulmonary clinic for workup of hypoxemia. He had a resting oxygen saturation on room air of 91%. Upon further questioning, he said he had been told about low saturations in the past, though he had always been asymptomatic, and no workup was pursued until now.
CASE PRESENTATION: Arterial blood gas performed on room air demonstrated pH 7.48, pCO2 30mmHg, pO2 56mmHg. He had normal pulmonary function tests, including a DLCO of 100% predicted when corrected for anemia. Ventilation/perfusion scan found no mismatched perfusion and ventilation defects in the lungs. He felt “funny” during the procedure, was transiently unable to move his right side, and tracer deposition was seen in the kidneys and brain, indicative of a right to left shunt. The peripheral intravenous catheter (IV) used for this study had been placed in his left forearm. A transthoracic echocardiogram with agitated saline contrast showed contrast entering the left atrium directly when a left forearm IV was used and documented an additional left-sided structure with venous flow. Computed tomography scan of the chest confirmed the presence of a left-sided superior vena cava (SVC) emptying into the left atrium (figure 1).
DISCUSSION: Although it is the most common congenital thoracic vascular malformation, persistent left-sided SVC (PLSVC) is rare, with a prevalence of about 0.3 - 0.5% among patients without congenital heart disease1, 2. PLSVC may be present with or without a right-sided SVC; when bilateral SVCs are present, they may be separate or connected by an innominate vein. Typically (80%) of PLSVC drain into the right atrium via a dilated coronary sinus, whereas only approximately 10% of PLSVC drain directly into the left atrium1. This last anatomic variant is important for chest physicians to recognize, as it can make left-sided central venous access challenging and risky: “paradoxical” embolism can result, including cerebral abscess2.
CONCLUSIONS: PLSVC causing hypoxemia, as in this patient, appears to be rare.
Reference #1: Biffi et al, Left Superior Vena Cava Persistence in Patients Undergoing Pacemaker or Cardioverter-Defibrillator Implantation. CHEST 2001; 120:139-144.
Reference #2: Povoski et al, Persistent left superior vena cava: Review of the literature, clinical implications, and relevance of alterations in thoracic central venous anatomy as pertaining to the general principles of central venous access device placement and venography in cancer patients. World Journal of Surgical Oncology 2011, 9:173
DISCLOSURE: The following authors have nothing to disclose: Anna Brady, Rosemary Adamson
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