Evaluation of liver transplant candidates: A pulmonary perspective

Abstract

Chronic liver disease is one of the leading causes of mortality and morbidity in the worldwide adult population. Liver transplant is the gold standard therapy for end-stage liver disease and many patients are on the waiting list for a transplant. A variety of pulmonary disorders are encountered in cirrhotic patients. Pleura, lung parenchyma, and pulmonary vasculature may be affected in these patients. Hypoxemia is relatively common and can be asymptomatic. Hepatopulmonary syndrome should be investigated in hypoxic cirrhotic patients. Gas exchange abnormalities are common and are generally correlated with the severity of liver disease. Both obstructive and restrictive types of airway disease can be present. Abnormal diffusion capacity is the most frequently observed pulmonary function disorder in patients with cirrhosis. Hepatic hydrothorax is another finding which is usually seen in conjunction with, but occasionally without ascites. Portopulmonary hypertension is a complication of long standing liver dysfunction and when severe, is accepted as a containdication to liver transplant. Since respiratory disorders are common and have significant impact on postoperative outcome in patients undergoing liver transplant, a careful preoperative pulmonary assessment is important.

Novel role of midodrine in pulmonary hypertension in liver transplant candidates

“…On the other hand, liver patients with PVH have a PAWP > 15 mm Hg. (1,4) To further differentiate between the 2 forms of PVH, patients with elevated pulmonary artery pressures due to high CO tend to have a high normal to mildly elevated PAWP compared to states of elevated blood volume due to intercompartmental shifts. We have described 3 patients with PoPH who at varying durations after their initial diagnosis were noted to have a change in hemodynamic profile to PVH, an entity not routinely seen in patients with other forms of group I PH.…”

“…Although the exact pathophysiology continues to be debated, the current understanding faults the shear stress acting on the pulmonary arteries by the high cardiac output (CO) state as one of the culprits for the vascular remodeling. (1,3) Pulmonary venous hypertension (PVH), increasingly recognized in liver transplant candidates, has a hemodynamic profile consistent with mPAP 25 mm Hg and PAWP > 15 mm Hg on RHC. The etiology of PVH in this population has been attributed either to high CO states or increased blood volume due to fluid shifts.…”

Perioperative Risk Assessment and Management of Cirrhotic Patients

“…When HPS is suspected, evaluation includes contrast echocardiography for intrapulmonary shunting [46]. The strongest predictor of postoperative death was PO2<50 mmHg or large intrapulmonary shunts.…”

“…The strongest predictor of postoperative death was PO2<50 mmHg or large intrapulmonary shunts. Current HPS management options are dismal [46], restricted to oxygen administration, supplemental care, and LT with 75% 5-yr survival of HPS post-LT vs. 23% without [47]. When POPH is suspected, transthoracic echocardiography is the best noninvasive test (100% Sn, 88% Sp), while right heart catheterization is the gold standard evaluating PAP ≥50 mmHg [46].…”

“…Current HPS management options are dismal [46], restricted to oxygen administration, supplemental care, and LT with 75% 5-yr survival of HPS post-LT vs. 23% without [47]. When POPH is suspected, transthoracic echocardiography is the best noninvasive test (100% Sn, 88% Sp), while right heart catheterization is the gold standard evaluating PAP ≥50 mmHg [46]. POPH management options include prostanoids, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors, while the most effective long term solution is LT [47,48].…”