Coronary air embolism during transcatheter patent foramen ovale closure for platypnea-orthodeoxia syndrome in a patient with severe respiratory disorder: a case report.

BACKGROUND: Coronary air embolism (CAE) is a rare and life-threatening complication of endovascular procedures, mostly due to procedure-related causes.

CASE SUMMARY: A 70-year-old man with severe respiratory disorder presented with patent foramen ovale (PFO)-related platypnea-orthodeoxia syndrome (POS). Transcatheter PFO closure was performed under local anaesthesia and intracardiac echocardiographic guidance. After a 5-Fr catheter was passed through the PFO via a 7-Fr femoral vein sheath, the patient suddenly coughed and breathed deeply. Thereafter, intracardiac echocardiography showed massive microbubbles in all cardiac chambers and the ascending aorta, and an electrocardiogram showed ST-segment elevations in the anterior and inferior leads. Emergency coronary angiography confirmed occlusion of the mid-left anterior descending artery, suggesting CAE. As the intracoronary infusion of saline, nitroglycerine, and nicorandil was ineffective, we performed air aspiration using a thrombectomy device, achieving coronary blood flow improvement and ST-segment resolution. Thereafter, positive pressure support using manual bag-valve-mask ventilation under intravenous sedation supported successful transcatheter PFO closure without further air embolization.

DISCUSSION: In this case with severe respiratory dysfunction, spontaneous deep breathing (spontaneous Valsalva manoeuvre) caused negative intrathoracic pressure and large drops in intravascular pressure. This phenomenon might have induced air contamination during device advancement, either by entrapping or leaving residual air in the gaps between the catheter and the sheath. Additionally, PFO with right-to-left shunts is more likely to cause paradoxical air embolization. Thus, the spontaneous Valsalva manoeuvre should be avoided with appropriate respiratory management to prevent paradoxical air embolization, including CAE, during transcatheter PFO closure under local anaesthesia in severe respiratory dysfunction patients.