[home] [Personal Program] [Help]

---

Session: Cardiac Diagnostics
Session starts: Friday 25 January, 10:30
Presentation starts: 11:00
Room: Lecture room 559

---

Tim Marcus (VU University Medical Center, Dept of Physics & Medical Technology )
Marielle van de Veerdonk (VU University Medical Center, Dept of Pulmonology)
Frank Oosterveer (VU University Medical Center, Dept of Pulmonology)
Anton Vonk Noordegraaf (VU University Medical Center, Dept of Pulmonology)
Ruud Verdaasdonk (VU University Medical Center, Dept of Physics & Medical Technology )

Abstract:
Introduction In pulmonary arterial hypertension (PAH), the overloaded right ventricle becomes stiffer, leading to increase of the right ventricular end-diastolic pressure (RVEDP) and the right atrium (RA) pressure. The subsequent impaired venous return may become manifest by reflux in the Vena Cava (VC). The aim of this study was to explore the associations between VC reflux, RA pressure and RVEDP in PAH. Methods In 35 patients, the volumetric flow in both the VC superior and inferior was measured using MRI phase-contrast velocity quantification. The fraction of backward flow in the VC was calculated by dividing the total reverse volume by the total forward volume per heartbeat. By invasive right heart catheterisation, the right ventricular end-diastolic pressure (RVEDP) and the right atrial maximum pressure (RAP_max) were recorded. Associations were assessed by linear regression. Results For 8 patients, the VC backflow fraction was above 20%, thus severely impairing the effective venous return. For the whole patient group, the VC backflow fraction was related to the RAP_max (p< 0.00001, r=0.73). RAP_max was related to RVEDP (p<0.000001, r=0.81), and the VC backflow fraction was related to RVEDP (p<0.000001, r=0.73). Discussion In case of RV diastolic dysfunction, the RA pressure is not able to overcome the increased RVEDP at end-diastole, resulting in partial atrial backward ejection into the low-pressure VC. The backflow volume can become so large, because there are no effective valves between RA and VC. Thereby this backflow phenomenon is hemodynamically very disadvantageous, and may well be the explanation for the prognostic value of RA pressure in PAH, as assessed by Benza et al. (2010). By MRI, the PAH treatment can be monitored non-invasively, and therapy can be optimized for the individual patient. Conclusion Backward flow in the VC is associated with increased right atrial pressure and RV end-diastolic pressure in PAH. This explains the impact of RV diastolic dysfunction on right atrial pressure and subsequently on the venous return in PAH. Reference Benza RL et al, Predicting survival in pulmonary arterial hypertension: insights from the Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management (REVEAL). Circulation. 2010 Jul 13;122(2):164-72.