LTSI Consensus Guidelines: Preoperative Pulmonary Evaluation in Adult Liver Transplant Recipients.

The relationship between chronic liver disease and respiratory symptoms and hypoxia is well recognized. Over the last century, three pulmonary complications specific to chronic liver disease (CLD) have been characterized: hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax. Apart from that coexisting pulmonary disease like chronic obstructive lung disease and interstitial lung disease also complicate the outcomes after liver transplantation (LT). Assessment for evaluation of underlying pulmonary disorders is essential to improve outcomes in patients with CLD, posted for LT. This consensus guideline of the Liver Transplant Society of India (LTSI) provides a comprehensive review of pulmonary issues in CLD, related and unrelated to underlying liver disease and gives recommendations for pulmonary screening in specific clinical scenarios in adults with chronic liver disease planned for LT. This document also aims to standardize the strategies for preoperative evaluation of these pulmonary issues in this subset of patients. Proposed recommendations were based on selected single case reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Additionally, this review will highlight the lacunae in our current evaluation strategy, challenges faced, and will provide direction to potentially useful futuristic preoperative evaluation strategies.

Endothelial glycocalyx in hepatopulmonary syndrome: An indispensable player mediating vascular changes.

Hepatopulmonary syndrome (HPS) is a serious pulmonary vascular complication that causes respiratory insufficiency in patients with chronic liver diseases. HPS is characterized by two central pathogenic features-intrapulmonary vascular dilatation (IPVD) and angiogenesis. Endothelial glycocalyx (eGCX) is a gel-like layer covering the luminal surface of blood vessels which is involved in a variety of physiological and pathophysiological processes including controlling vascular tone and angiogenesis. In terms of lung disorders, it has been well established that eGCX contributes to dysregulated vascular contraction and impaired blood-gas barrier and fluid clearance, and thus might underlie the pathogenesis of HPS. Additionally, pharmacological interventions targeting eGCX are dramatically on the rise. In this review, we aim to elucidate the potential role of eGCX in IPVD and angiogenesis and describe the possible degradation-reconstitution equilibrium of eGCX during HPS through a highlight of recent literature. These studies strongly underscore the therapeutic rationale in targeting eGCX for the treatment of HPS.

HEPATO-PULMONARY SYNDROME: LOOK CLOSELY OR YOU MIGHT MISS IT

CASE: A Hispanic-speaking 63-year-old lady presented with left shoulder pain and dyspnea since two weeks. Past history was significant for cirrhosis due to autoimmune hepatitis and portal hypertension diagnosed 1.5 years prior. Upon further questioning, she revealed that she had exertional dyspnea for 2 years, which got progressively worse after her COVID-19 infection, 14 months prior. On initial exam, her hemoglobin levels were unchanged with previous. Troponin and BNP levels were unremarkable. CT Pulmonary Embolus scan and shoulder X-ray were negative. However, her SpO2 which was 90% on lying flat, fell to 84% on walking and she was admitted for further workup. On exam, she had a loud S2, spider angioma, and clubbing. ABG showed an alveolar-arterial oxygen gradient of 54.7 mm and PO2 of 61.7 mm. A contrastenhanced transthoracic echo with saline showed significant shunting with dilated pulmonary veins. Upon close inspection, she had a small right to left intracardiac shunt through an incidental PFO and a rather large intrapulmonary shunt. This was confirmed on trans-esophageal echo. Right heart catheterization showed a high cardiac index (5.3 L/min) suggestive of a high-output state, as typically seen with cirrhosis. It also revealed increased right-sided oxygen saturations, confirming the presence of a significant left to right shunt. Finally, pulmonary CT angiography was negative for AVMs. These findings were congruent with hepato-pulmonary syndrome (HPS) and based on her presenting symptoms she was referred to hepatology for consideration of liver transplantation. IMPACT/DISCUSSION: HPS is characterized by abnormal oxygenation due to intrapulmonary vascular dilations (IPVD) in the setting of advanced liver disease. Diagnosis needs an elevated A-a gradient (≥ 15mm or ≥ 20 mm if >64 years). IPVDs may not be seen on CT scans and are optimally detected on CE-TTE. The delayed appearance of injected microbubbles in the left heart, 3 or more cardiac cycles after visualization in the right heart signifies abnormally dilated pulmonary capillaries which don't trap the bubbles. TTE can help differentiate intracardiac and intrapulmonary shunts, by revealing the source of the microbubbles entering into the left atrium (across the atrial septum vs pulmonary veins). Shunting classically causes platypnea-orthodexia (worsening dyspnea on standing or sitting, alleviated by lying down). Alterations in lung parenchyma due to COVID-19 could have increased the flow through intrapulmonary AVMs and contributed to the worsening of symptoms. Management of HPS is supportive. Liver transplantation improves survival. CONCLUSION: Evaluation and management of HPS involves multiple modalities of testing and specialists in gastroenterology, cardiac imaging, interventional cardiology, interventional radiology, and transplant surgery. The diagnosis of HPS should escalate referral to a liver transplant center. Engaging medical interpreters can help elicit more detailed history and improve clinical outcomes.

Baby Blues: A Rare Case of Transient Pulmonary Arteriovenous Malformation During Pregnancy

Unexplained hypoxia in a pregnant patient is an alarming finding for patient and provider. The differential for hypoxia is broad, and many imaging techniques and procedures are contraindicated in pregnancy. Transient pulmonary arteriovenous malformations (AVMs) are a rare and relatively poorly studied cause of hypoxia in pregnancy. Our patient is a 27-year-old G1P0 female with a remote history of asthma who presented to clinic with slowly progressive exertional dyspnea, exertional tachycardia, and paroxysmal nocturnal dyspnea. She reported use of a home oximeter which read in the high 80s% during exertion. Prior to presentation, the patient was evaluated in the Emergency Department and noted to have an oxygen saturation of 86% on room air. A transthoracic echocardiogram, computed tomography angiography of chest, and basic laboratories including B-type natriuretic peptide, troponin, COVID-19, and hemoglobin were unremarkable. Her clinical timeline is presented in Figure 1. Further testing was obtained, including pulmonary function testing, bubble echocardiogram, nocturnal oximetry, and shunt study. Work-up revealed a 15-20% shunt, depending on calculation, and insignificant desaturations during nocturnal oximetry. Her symptoms progressed, and repeat nocturnal oximetry showed marked overnight desaturations requiring supplemental oxygen for the remainder of her pregnancy. She delivered a healthy baby girl via cesarean section without serious complication. Repeat testing in the post-partum period showed resolution of nocturnal desaturations and decreased shunt, and her exertional dyspnea and desaturations resolved spontaneously. This case illustrates the challenging diagnosis of transient pulmonary AVM in pregnancy. Case reports of this phenomenon have been published, but as in our case, no definitive diagnosis was made secondary to testing limitations in pregnancy and quick resolution of symptoms in the post-partum period. Some reports describe pre-existing pulmonary AVM becoming worse during pregnancy causing hemothorax, fetal demise and even death. While the mechanism is not known, theories include the vasodilatory effects of progesterone on vascular smooth muscle as well as other physiologic changes in pregnancy such as increased plasma volume. These AVM are thought to be like those seen in hepatopulmonary syndrome. Similar to our case, increasing positional hypoxia has been reported as the pregnancy progresses. Further research dedicated to early and accurate detection of pulmonary AVMs in pregnancy is necessary. (Figure Presented).

Hypoxia in Liver Cirrhosis (Liver Specific and Systemic Causes)

Background: During this covid pandemic hypoxia was one of the initial mode of screening diagnosis and follow-up. Hypoxia in liver cirrhosis patients is also not uncommon especially in late stages. Hypoxia can have varied causes either liver specific or systemic conditions. Aim: aim of our observational study was to find etiology, incidence, severity and hypoxia related mortality in patients with liver cirrhosis. Methods: we conducted an observational study over a period of two months a total of n=64 patients with liver cirrhosis with hypoxia were included in the study. Further follow up data was collected from their clinical work up. Mortality data was collected for their mean follow up periods from their inclusion in the study. Results: ACLF was found to be the most common cause of hypoxia in cirrhosis patients with n=24 (37.5%) with a mean spo2 of 86.4% Mortality in ACLF was 70.8%, second most common cause was covid pneumonitis n=17 (26.6%) with a mean spo2 of 82.6% and a mortality of 23.5%, Followed by sepsis n=10 (15.6%) with an average spo2 of 88% and mortality of 60%. Hepato-pulmonary syndrome was seen in n=8 (12.5%) average spo2 of 91% and mortality of 25% followed by hepatic and hydrothorax n=4 (6.25%) average spo2 of 92.5% with 25% mortality and one patient with porto- pulmonary syndrome with an spo2 of 93% no mortality. Conclusion: Novel corona virus induced hypoxia was second most common causes for hypoxia in the current pandemic era after ACLF. Though hypoxia in COVID pneumonitis was more severe than ACLF and sepsis but the mortality was higher in ACLF and sepsis subgroup. Prognosis and mortality in hypoxic cirrhosis depends on the etiology and does not directly corelate with the severity of spo2 directly.

Hypoxemia, high alveolar-arterial gradient, and bubbles in both sides of heart: A case of hepatopulmonary syndrome in the setting of COVID-19 pandemic.

In presence of tachypnea, digital clubbing and cyanosis in a patient with the hallmarks of chronic liver disease, hepatopulmonary syndrome should be suspected and investigated.