Valsalva and orthostatic maneuvers increase liver stiffness (Fibroscan®) in healthy volunteers

Aims: Measurement of liver stiffness (LS) by transient elastography [Fibroscan (FS)] is a novel non-invasive approach to assess liver fibrosis/cirrhosis. We have previously shown that patients with cardiac inufficiency have drastically increased liver stiffness independent of fibrosis state. We here study whether hemodynamic changes in healthy volunteers (Valsalva and Schellong maneuver) affect liver stiffness.

Methods and results: Liver stiffness was measured in 25 healthy individuals without history of liver disease in horizontally reclined, sitting and upright standing position. Measurements were performed while the test person was either breathing normally or performing a Valsalva maneuver (forcibly exhaling against a closed airway) to increase the intrathorakal pressure. Surprisingly, more than 50% of volunteers managed to increase LS over 12.5 kPa the typical LS threshold for F4 fibrosis. Some individuals even reached a LS of 75 kPa the upper detection limit of FS. Three groups of individuals could be distinguished: group A (n=5) with no significant change in LS in any position (median FS ≤5kPa), group B (n=10) with mild increase of LS during Valsalva maneuver (median FS between 5 and 12 kPa) and group C (n=10) with dramatic LS increase during the Valsalva maneuver. Maneuver-dependent increase of LS was significantly associated with younger age (standing upright r=0.65, p<0.001; sitting position r=0.419, p=0.04) but not with weight, height or body mass index. Standing or sitting position increased the ability to increase LS during the Valsalva maneuver (p=0.007, Sign test).

Discussion and conclusion: We here show that vertical body position and breathing maneuvers can strongly increase liver stiffness in healthy individuals. Thus, for reliable fibrosis assessment, horizontal positioning is required. The diagnostic relevance of dramatically increased LS in response to orthostatic challenges in some individuals should be addressed in future studies e.g. with respect to orthostatic syncopes.