Use of invasive cardiopulmonary exercise testing to diagnose preload reserve failure in patients with liver disease.

In this case series, we describe the use of invasive cardiopulmonary exercise testing (iCPET) to diagnose heart failure due to preload reserve failure in two patients with progressive dyspnoea. We demonstrate that underlying liver disease contributes to preload reserve failure as a cause of exertional dysfunction. In liver diseases such as non-alcoholic fatty liver disease (NAFLD), fibrotic changes to the sinusoidal liver architecture occur leading to an increased transhepatic sinusoidal pressure gradient. Even at the earliest stage of hepatic fibrosis in patients with NAFLD, changes in hepatic blood flow are seen due to outflow block in the sinusoidal area. In this way, changes to the sinusoidal liver architecture can lead to limitations in preload reserve. This case series describes two patients with exertional dyspnoea found to have preload failure on iCPET due to underlying liver disease.