Dynamic shunt flow alterations through patent foramen ovale during off-pump coronary artery bypass grafting induced by airway pressure changes: a case report

Ayano Honda; Koichi Yoshinaga; Yuji Hirasaki; Yusuke Iizuka; Yuji Otsuka

doi:10.1186/s40981-024-00748-7

Dynamic shunt flow alterations through patent foramen ovale during off-pump coronary artery bypass grafting induced by airway pressure changes: a case report

JA Clin Rep. 2024 Oct 15;10(1):65. doi: 10.1186/s40981-024-00748-7.

Authors

Ayano Honda¹, Koichi Yoshinaga², Yuji Hirasaki^{1

3}, Yusuke Iizuka¹, Yuji Otsuka¹

Affiliations

¹ Department of Anesthesiology and Critical Care Medicine, Jichi Medical University Saitama Medical Center, 1-847 Amanuma-Cho, Omiya-Ku, Saitama-Shi, Saitama, 330-8503, Japan.
² Department of Anesthesiology and Critical Care Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-Shi, Tochigi, 329-0498, Japan. kyoshinaga@jichi.ac.jp.
³ Department of Anesthesiology, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi-Cho, Utsunomiya-Shi, Tochigi, 321-0974, Japan.

Abstract

Background: Interatrial right-to-left shunt flow through a patent foramen ovale (PFO) can be caused by changes in heart position for anastomosis during off-pump coronary artery bypass (OPCAB). We herein present a case in which the direction of PFO shunt flow changed with heart position during OPCAB and the ventilation settings after sternal closure.

Case presentation: A 66-year-old man with interstitial pneumonia underwent OPCAB. Preoperative transesophageal echocardiography revealed right-to-left shunt flow through a PFO induced by the Valsalva maneuver. During OPCAB, heart displacement resulted in right-to-left shunting and acute hypoxemia, which quickly improved with increase of inspired oxygen fraction. After chest closure, bidirectional shunt flow developed under increased airway pressure.

Conclusions: Vigilant intraoperative monitoring with TEE and postoperative airway pressure management are important to address shunt flow and hypoxemia due to PFO.

Keywords: Bidirectional shunt; Hypoxemia; Off-pump coronary artery bypass grafting; Patent foraman ovale; Postoperative management.