(B-77) Femoral Venous Distention and Intrabdominal Pressure as Mechanical Triggers of Thromboembolic Events

Introduction:: Emboli are caused by thrombus fracture or detachment from the vessel wall ultimately resulting in downstream vascular obstruction. Unfortunately, the underlying mechanisms that trigger its detachment are not fully understood. Venous distention in response to increased central pressure is not only a marker for medical conditions such as right heart failure and abdominal compartment syndrome but may also be a potential cause for thromboembolic events.[1] Given the high capacitance of veins, we conjectured that increases in central pressure can lead to proportional increases in high venous distention and wall stress, potentially serving as a mechanical trigger for thromboembolic events. In this study, we aim to investigate the relationship between acute increases in intra-abdominal pressure induced by the Valsalva maneuver and the resulting changes in venous distention as observed through Point-of-care ultrasound (POCUS) imaging.


Materials and Methods:: The right femoral veins of 13 participants were recorded using a portable Butterfly IQ+ Ultrasound while performing the Valsalva Maneuver in a supine position. Each participant completed three trials, in which a sphygmomanometer was used to achieve intraabdominal pressures of 10, 20, and a maximum (30-60) mmHg, with a 2-minute rest period between each recording. Baseline and post-resting pressures were recorded at the beginning and end of the experiment, respectively. An in-house image processing software (MATLAB, 2023) was employed to detect changes in venous distention for each pressure level. (Fig.1A)


Results, Conclusions, and Discussions:: The results of this study show a significant increase in venous diameter in response to increasing intrabdominal pressures compared to a resting state. (Fig.1B) We also observed good reproducibility to measure venous response to intra-abdominal stepwise pressure increases. (Fig. 1C). Our results suggest that acute increases in intra-abdominal pressure can result in proportional increases in venous pressure and diameter, which may increase wall stress in the vessel and could be a potential mechanical trigger for thromboembolic events.
In conclusion, this study demonstrates the feasibility of using POCUS imaging to measure changes in venous distention in response to the increasing intra-abdominal pressures during the Valsalva maneuver. Further research is needed to determine the relationship between venous distention and thromboembolism, but our findings provide valuable insights into the underlying mechanisms of venous distention and its potential role in the pathogenesis of thromboembolic events.




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References (Optional): : [1] P. Łagosz, M. Sokolski, J. Biegus, A. Tycinska, and R. Zymlinski, “Elevated intra-abdominal pressure: A review of current knowledge,” World J Clin Cases, vol. 10, no. 10, p. 3005, Apr. 2022, doi: 10.12998/WJCC.V10.I10.3005.