Magnetic resonance imaging-derived parameter of portal flow predicts volume-mediated pulmonary hypertension in liver transplantation candidates.

BACKGROUND

Pulmonary hypertension is a source of perioperative mortality after orthotopic liver transplantation (OLT). The purpose of this study is to (1) characterize the pulmonary hemodynamic response in OLT candidates, and (2) determine whether portal flow index (PFI), a magnetic resonance imaging (MRI)-derived parameter, is a useful predictor of the pulmonary hemodynamic response.

METHODS

Twenty-five consecutive OLT candidates underwent right heart catheterization with pressure measurements at baseline and after infusion of 1 L of crystalloid. MRI, chest roentgenography, electrocardiography, and echocardiography were also performed as routine screening techniques. Sixteen patients in intensive care unit with normal liver function served as controls.

RESULTS

After volume infusion, pulmonary hypertension (mean pulmonary artery pressure greater than 25 mm Hg) developed in 9 of 25 OLT candidates with elevations in both pulmonary capillary wedge and mean pulmonary pressures. In contrast, 0 of 16 controls experienced pulmonary hypertension (p < 0.01). Although routine modalities did not predict this hemodynamic response, PFI had a 94% specificity and 78% sensitivity.

CONCLUSIONS

OLT candidates exhibit volume-induced pulmonary hypertension with responses suggestive of left ventricular dysfunction. The significance of this observation is unknown, but the MRI-derived parameter, PFI, may serve as a screening technique to limit catheterization to a select group of OLT candidates.