A new diagnostic modality: the standing bubble study

SESSION TITLE: Cardiovascular Disease Case Report Posters 10 SESSION TYPE: Case Report Posters PRESENTED ON: 10/09/2023 02:10 pm - 02:55 pm INTRODUCTION: Extra-cardiac right-to-left shunts are a relatively rare cause of hypoxia in adults, often requiring a high index of suspicion to diagnose. We present a case of a 60-year-old male with worsening respiratory failure without obvious pulmonary or cardiac etiology. He had a prior negative echocardiographic evaluation for shunt with agitated saline in the recumbent position. However, repeating the study in the standing position revealed extra-cardiac shunting leading to the diagnosis of cirrhosis and hepatopulmonary syndrome. CASE PRESENTATION: A 60-year-old male with a past medical history of sarcoidosis on 3 L/min of nocturnal home oxygen, hyperlipidemia, hypertension, thrombocytopenia, and alcohol use presented initially with rectal bleeding. His hospital course was complicated by worsening hypoxic respiratory failure, which was exacerbated in the seated and standing positions and improved while in the recumbent position, a phenomenon known as platypnea-orthodeoxia syndrome. The patient stopped smoking more than 30 years ago and had no occupational respiratory inhalation exposure. The patient was previously evaluated by multiple cardiologists and pulmonologists, with no clear etiology of his shortness of breath. Prior cardiac studies were all negative, including an echocardiogram with agitated saline, cardiac MRI, and a nuclear stress test. While admitted to the hospital, the decision was made to repeat echocardiogram with agitated saline which again did not show evidence for shunting and showed a normal systolic and diastolic function as well as normal global longitudinal strain. Right heart catheterization was performed and showed normal pulmonary artery pressures, normal wedge pressure, and no evidence of shunt physiology. Due to high clinical suspicion for shunt physiology, echocardiogram with agitated saline was performed in the standing position and revealed a positive study, with the presence of bubbles on cardiac cycle 5, indicative of extra-cardiac shunting. Ultimately, a nuclear medicine shunt study was performed, showing evidence of right-to-left shunt of 26%. Transvenous jugular biopsy was performed with histology consistent with cirrhosis, aiding the diagnosis of hepatopulmonary syndrome (HPS). Orthotopic liver transplantation (OLT) evaluation was completed, and the patient remains on the transplant list. DISCUSSION: Platypnea-orthodeoxia syndrome is a condition of positional dyspnea and hypoxemia, which occurs when the patient is upright and resolves quickly with recumbency caused by either intra-cardiac or extra-cardiac etiologies. Hepatopulmonary syndrome, occurring in 1-2% of cirrhotic patients, is a cause for extra-cardiac shunting, with the mechanism thought to be related to V/Q mismatch, which is exacerbated in the standing position due to increased blood flow through the arteriovenous shunts located in the basilar regions of the lung during standing. CONCLUSIONS: In a patient presenting with platypnea-orthodeoxia, an echocardiogram with agitated saline can be an essential diagnostic tool when differentiating between intra-cardiac and extra-cardiac shunting. In cases with high index of suspicion for shunt physiology with a previous negative echocardiogram with agitated saline, it may be beneficial to evaluate shunting in both the recumbent and upright positions. REFERENCE #1: Henkin S, Negrotto S, Pollak PM, Cullen MW, O'Cochlain DF, Wright RS. Platypnea-Orthodeoxia Syndrome: Diagnostic Challenge and the Importance of Heightened Clinical Suspicion. Tex Heart Inst J. 2015 Oct 1;42(5):498-501. doi: 10.14503/THIJ-14-4596. PMID: 26504452; PMCID: PMC4591898. REFERENCE #2: "Hepatopulmonary Syndrome." Hepatopulmonary Syndrome - an Overview | ScienceDirect Topics, https://www.sciencedirect.com/topics/medicine-and-dentistry/hepatopulmonary-syndrome#:~:text=Hepatopulmonary%20syndrome%20(HPS)%20is%20characterized,of%20cirrhosis%20and%20portal%20hypertension. DISCLOSURES: No relevant relationships by Vincent Chan No disclosure on file for Shujaul Haq No relevant relationships by Mackenzie Kramer No relevant relationships by Michael Lake No relevant relationships by Margaret Mack No relevant relationships by Nayab Nadeem No relevant relationships by Tirth Patel No relevant relationships by Sohaib Roomi No relevant relationships by Rehan Saeed No relevant relationships by Stephanie Tzarnas