PO-04-028 INTERATRIAL SHUNT LEADING TO SEVERE HYPOXEMIA: A RARE COMPLICATION OF PACEMAKER-ASSOCIATED INFECTIVE ENDOCARDITIS

Abstract

Pacemaker-lead-associated infective endocarditis is a serious complication with high morbidity and mortality. We present a case of persistent hypoxemia from significant right to left atrial shunting across the patent foramen ovale (PFO) as a result of pacemaker-lead-associated infective endocarditis with large vegetations. N/A A 56-year-old female with stroke, sleep apnea, diabetes mellitus, hypertension, and sick sinus syndrome with dual chamber pacemaker implantation, was admitted with acute hypoxic respiratory failure requiring high flow nasal cannula. A chest x-ray did not show any obvious etiology of hypoxemic respiratory failure. Arterial blood gas showed no hypercapnia ruling out hypoventilation as the cause of hypoxemia. A very high A-a gradient was noted, raising suspicion for shunting. Blood cultures were positive for staphylococcus capitis bacteremia. A transesophageal echocardiogram (TEE) showed several large vegetations (Image A) attached to the atrial and ventricular lead, tricuspid valve with associated severe tricuspid regurgitation, and a PFO (Image B) with a large right to left shunt as a result of large right-sided vegetations (Image C). A pacemaker extraction procedure was planned; however, there was a concern for paradoxical septic embolism across the PFO. As such, an ASD occluder device was temporarily placed across the PFO during the procedure to prevent right-to-left embolization. PFO occlusion dramatically improved hypoxemia during the procedure. The infected pacemaker system was then successfully extracted. The PFO occluder device was subsequently removed at the end of the case, given ongoing bacteremia and the risk of device seeding. The patient recovered well with the resolution of hypoxemia and was discharged however presented again one month later with a stroke. TEE exam showed a large echo-dense lesion straddling the atrial septum through the PFO, likely vegetation that embolized to the left circulation causing the stroke (Image D). The patient is currently awaiting cardiac surgery for definitive treatment once medically stable. Pacemaker-associated infective endocarditis can lead to mechanical complications, including tricuspid regurgitation and rarely shunting across the atria, causing severe hypoxemia as in our patient. There are no clear guidelines regarding the management of such atrial defects with shunting peri-device extraction to prevent systemic embolization of vegetations.