Severe hypoxemia caused by right-to-left shunt through a patent foramen ovale associated with right coronary artery malperfusion secondary to acute aortic dissection: a case report

Background Right coronary artery malperfusion associated with acute type A aortic dissection can cause right ventricular failure. However, hypoxemia due to a right-to-left shunt through a patent foramen ovale secondary to elevated right-sided cardiac pressure has rarely been described in this setting. Case presentation An 80-year-old woman with acute type A aortic dissection presented with hypoxemia unexplained by pulmonary disease. Transesophageal echocardiography suggested that right ventricular dysfunction associated with right coronary artery malperfusion had contributed to right-to-left shunting through a patent foramen ovale. Following ascending aortic replacement, she developed hypoxemia after separation from cardiopulmonary bypass. Transesophageal echocardiography showed persistent right ventricular dysfunction and worsening of the shunt. Intraoperative optimization of cardiovascular medications improved hemodynamics, reduced the shunt, and improved oxygenation. Conclusions This case suggests that intracardiac right-to-left shunting should be considered in patients with acute aortic dissection and unexplained hypoxemia, and that transesophageal echocardiography may guide perioperative management.