C65-03 End-Stage Renal Disease and Pulmonary Hypertension: Pulmonary Vascular Resistance Changes After a Transient Arteriovenous Fistula Occlusion

Purpose Right heart catheterization (RHC) is routinely performed to evaluate kidney transplant candidates suspected of having pulmonary hypertension (PH). Accurate assessment of hemodynamics, including pulmonary vascular resistance (PVR), is crucial in this patient group, given their higher risk of post-transplant complications (1). In this population, a thermodilution (TD) cardiac output (CO) will reflect an increased venous return from the arteriovenous fistula (AVF). Since CO is an integral component of the PVR calculation, we sought to compare PVR values before and after a transient fistula occlusion to assess the severity of PH more accurately. Methods We retrospectively identified kidney transplant candidates who underwent diagnostic RHC for suspected PH between January 2021 and January 2025. We then selected consecutive patients with an AV fistula who underwent a transient fistula occlusion and had full hemodynamic calculations before and after occlusion. Statistical analyses were performed using non-parametric testing, including the non-parametric Wilcoxon Signed-Rank test Results Ten patients were included. Eighty percent were male with a mean age of 59 years. Baseline median values included: TD CO 6.8 L/min, mean pulmonary artery pressure (mPAP) 40 mmHg, wedge pressure (WP) 18 mmHg, and PVR 2.79 Wood units (WU). After a 5+ minute fistula occlusion, values included: TD CO 6.38 L/min, mPAP 37.5 mmHg, WP 21 mmHg, and PVR 2.8 WU. Despite a drop in TD CO by about 0.5 L/min, there was no statistical difference using a Wilcoxon Signed-Rank test between baseline and post-fistula occlusion TD CO values (p = 0.21). Baseline and post-occlusion PVR didn’t show a significant change either, with values of 2.79 WU and 2.75 WU, respectively (p = 0.49). Conclusions Despite a significant drop in TD CO values after a fistula occlusion, other transient hemodynamic changes occur, maintaining a similar degree of vascular resistance. Clinical Implications Pulmonary hypertension in ESRD is multifactorial and is associated with an increased risk of mortality and major adverse cardiovascular events post-kidney transplant (1). Transient AVF occlusion is a crucial aspect of the hemodynamic assessment for this patient population. In our small cohort of patients, there was no significant change in PVR by TD CO calculations after a fistula occlusion. REFERENCES: Jose, A. et al (2024). Association of Cardiopulmonary Hemodynamics and Outcomes in Pulmonary Hypertension Following Kidney Transplantation: A Multicenter Retrospective Cohort Study. Chest.