Abstract 17944: Pulmonary Vascular Reserve and Right Ventricular Contractile Reserve in Patients With Chronic Thromboembolic Disease Without Pulmonary Hypertension at Rest: An Exercise Cardiac Magnetic Resonance Study
Background: A significant number of patients with incomplete thrombus resolution after pulmonary embolism have marked exercise limitation despite normal resting hemodynamics.
Hypothesis: We investigated whether reduced exercise capacity in patients with chronic thromboembolic disease (CTED) can be explained by a reduced right ventricular (RV) contractile reserve and abnormal pulmonary vascular reserve.
Methods: Nine CTED patients, 18 patients with chronic thromboembolic pulmonary hypertension (CTEPH) and 9 controls underwent cardiopulmonary exercise testing and exercise cardiac magnetic resonance with simultaneous registration of invasive pulmonary pressures. Abnormal pulmonary vascular reserve was defined as an increase in mean pulmonary artery pressure to cardiac output (mPAP/CO slope) >3 mmHg/L/min and abnormal RV contractile reserve as a ratio of peak-exercise to resting RV end-systolic pressure/volume relationship (RVESPVR ratio) <2.
Results: Exercise capacity was reduced in CTEPH and CTED patients as reflected by a lower peak oxygen uptake and peak power (p ≤ 0.001). Mean pulmonary artery pressure at rest was higher in CTEPH (42.9±10.2 mmHg, p<0.001) but similar (p=0.173) in CTED (20.7±4.2) and controls (13.4±3.4). As expected, pulmonary vascular reserve was abnormal in CTEPH (9.4±5.52 mmHg/L/min) and CTED (3.38±1.91) but not in controls (1.88±0.9, p<0.001 for interaction). RV contractile reserve was also abnormal in CTEPH (1.38±0.25) and although mean was normal in CTED (2.16±0.63), it was significantly lower than controls (3.81±0.72, p<0.001 for interaction). Furthermore, 5 of 9 CTED patients (56%) had a RVESPVR ratio <2. The change in RV ejection fraction during exercise differed (p<0.001) with an increase in controls but not in CTED or CTEPH.
Conclusion: RV contractile reserve and pulmonary vascular reserve are reduced in a majority of CTED patients. Exercise testing can identify sub-clinical disease in these symptomatic patients.
Author Disclosures: M. Claeys: None. G. Claessen: None. R. Willems: None. T. Petit: None. C. Belge: None. A. La Gerche: None. J. Bogaert: None. M. Delcroix: None. P. Claus: None.
- © 2016 by American Heart Association, Inc.