Patent foramen ovale, bone cement implantation syndrome and paradoxical embolism : Case study and pathophysiological...

Patients with a patent foramen ovale (PFO) have an increased risk of perioperative cerebral stroke due to the potential for paradoxical embolism. It is pathophysiologically plausible that this risk is further increased when bone cement implantation syndrome (BCIS) occurs during endoprosthetic joint surgery; however, despite double-digit prevalence rates for both PFO and BCIS, the perioperative concurrence of these conditions with subsequent paradoxical embolism has not previously been reported.We describe an 81-year-old woman with a known PFO who developed intraoperative BCIS during cemented hip arthroplasty and subsequently sustained a paradoxical embolic stroke involving a large cerebral vessel. The potential pathophysiological links between PFO and BCIS are discussed, and anesthesiological implications and practical recommendations are derived from the current literature.Published estimates of paradoxical embolism risk during endoprosthetic joint replacement are highly inconsistent, ranging from no increased risk to a 29-fold increase. This variability may partly reflect that many embolic events remain clinically silent.For paradoxical embolism two conditions are required: (1) gaseous or particulate emboli must enter the venous circulation and (2) the physiological left-to-right interatrial shunt must reverse to a right-to-left shunt through the PFO. Both mechanisms can be promoted by BCIS by generating embolic load from the surgical field and increasing pulmonary vascular resistance, thereby favoring right-to-left shunting. Because specific anesthesiological preventive and therapeutic options are limited, close postoperative monitoring is essential and any new neurological or hemodynamic abnormalities should prompt immediate comprehensive diagnostic evaluation.