Refractory Hypoxemia After Left Ventricular Assist Device Implantation: Underestimated Patent Foramen Ovale and Venovenous Extracorporeal Membrane Oxygenation-Associated Sump Effect on Bubble Study

Makoto Kataoka; Satoshi Hanada; Edwin Becher; Roopa Rao

doi:10.1053/j.jvca.2026.05.052

$Refractory Hypoxemia After Left Ventricular Assist Device Implantation: Underestimated Patent Foramen Ovale and Venovenous Extracorporeal Membrane Oxygenation-Associated Sump Effect on Bubble Study$

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Refractory Hypoxemia After Left Ventricular Assist Device Implantation: Underestimated Patent Foramen Ovale and Venovenous Extracorporeal Membrane Oxygenation-Associated Sump Effect on Bubble Study

Makoto Kataoka, Satoshi Hanada, Edwin Becher and Roopa Rao

Journal of cardiothoracic and vascular anesthesia, Vol.40(10), pp.3355-3360

06/01/2026

DOI: 10.1053/j.jvca.2026.05.052

PMID: 42323236

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Abstract

Hypoxemia after left ventricular assist device (LVAD) implantation is a life-threatening complication with a wide differential diagnosis. One potentially catastrophic cause is right-to-left shunting through an unmasked or underestimated patent foramen ovale (PFO). We describe a 63-year-old man in whom an intraoperatively identified PFO with left-to-right flow was initially judged mild and unlikely to be clinically significant. However, on postoperative day 1 in the intensive care unit, profound refractory hypoxemia developed due to massive right-to-left shunting, requiring rescue venovenous (VV) extracorporeal membrane oxygenation (ECMO). Furthermore, a bedside agitated saline solution study (bubble study) performed by transesophageal echocardiography under full VV-ECMO support was confounded by the extracorporeal sump effect, wherein the high-velocity venous drainage cannula siphoned agitated saline solution and led to a significant underestimation of the intracardiac shunt. This case reinforces the argument for a low threshold for PFO closure at the time of LVAD implantation, given the inherent limitations of preoperative echocardiographic assessment in advanced heart failure: Even defects that appear mild may carry clinically significant risk after LVAD-mediated left atrial decompression. Additionally, clinicians should be aware that active ECMO venous drainage can mask or underestimate intracardiac shunting on bubble study and that transient reduction of extracorporeal flow is essential for accurate interpretation during concurrent ECMO support.

hypoxemia

patent foramen ovale

transesophageal echocardiography

left ventricular assist device

venovenous extracorporeal membrane oxygenation

sump effect

Details

Title: Subtitle: Refractory Hypoxemia After Left Ventricular Assist Device Implantation: Underestimated Patent Foramen Ovale and Venovenous Extracorporeal Membrane Oxygenation-Associated Sump Effect on Bubble Study
Creators: Makoto Kataoka - Indiana University – Purdue University Indianapolis
Satoshi Hanada - Indiana University School of Medicine
Edwin Becher - Indiana University School of Medicine
Roopa Rao - Indiana University School of Medicine
Resource Type: Journal article
Publication Details: Journal of cardiothoracic and vascular anesthesia, Vol.40(10), pp.3355-3360
DOI: 10.1053/j.jvca.2026.05.052
PMID: 42323236
NLM abbreviation: J Cardiothorac Vasc Anesth
ISSN: 1532-8422
eISSN: 1532-8422
Publisher: Elsevier
Language: English
Electronic publication date: 06/01/2026
Academic Unit: Anesthesia
Record Identifier: 9985176652302771

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