PARADOXICAL embolization is rare but possible in patients with a patent foramen ovale (PFO).1,2  The accompanying images exhibit impending paradoxical embolization. A serpentine clot, involving all cardiac chambers (top) is seen extending from right to left atrium via a PFO (bottom). Such a thrombus that exhibits independent motion is designated as a “clot in transit” (See Video, Supplemental Digital Content, http://links.lww.com/ALN/B550, which demonstrates clot motion). Emergency surgical embolectomy with cardiopulmonary bypass is indicated due to risk of catastrophic systemic embolization.2,3  Perioperative anesthetic management is challenging, because hemodynamic collapse occurs frequently. Unpredictable piecemeal or large thrombus embolization increases pulmonary vascular resistance (PVR) leading to acute right heart failure and decreased left ventricular filling. Anesthesia and tachyarrhythmia-induced hypotension compromise coronary perfusion, further worsening contractility and ventricular function.3  Consequently, hemodynamic collapse can ensue. Additionally, increased PVR causes right atrial pressure to exceed left atrial pressure, facilitating right-to-left shunting and clot propagation into left cardiac chambers through the PFO.

Anesthetic goals include decreasing PVR while maintaining systemic perfusion. Avoidance of hypoxemia, hypercarbia, and hypothermia is paramount. Preinduction institution of invasive arterial monitoring is imperative. Judicious preloading and low tidal volume ventilation help optimize right ventricular function. Use of inhalational nitric oxide and intravenous norepinephrine decreases PVR without causing systemic hypotension. Given that central venous catheterization can potentially cause further embolization, placement under transesophageal echocardiography guidance is prudent. Refractory hypotension or cardiac arrest can occur at or soon after induction, necessitating emergent institution of cardiopulmonary bypass.1 

The authors declare no competing interests.

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