P4670Long-term changes of exercise haemodynamics and physical capacity in chronic thromboembolic pulmonary hypertension after pulmonary thromboendarterectomy

Background A substantial number of chronic thromboembolic pulmonary hypertension (CTEPH) patients experience dyspnoea on exertion and limited exercise capacity despite surgically successful pulmonary endarterectomy (PEA). Purpose We sought to prospectively evaluate resting and peak exercise haemodynamics before, 3 and 12 months after PEA in consecutive CTEPH patients and correlate it to physical functional capacity. Methods Twenty CTEPH patients who underwent PEA treatment were examined between December 2014 and January 2017. The patients were examined pre-operatively and 3 and 12 months post-operatively with right heart catheterisation at rest and during a maximal symptom-limited, semi-supine cardiopulmonary exercise test. Finally, the data were compared with 15 healthy controls who had previously undergone the same protocol. Results Twelve months after PEA, 75% of patients with severely increased pre-PEA mean pulmonary arterial pressure (mPAP) at rest had normal or mildly increased mPAP. However, mPAP reduction was less pronounced during exercise where only 45% had normal or mildly increased mPAP at 12 months. Cardiac output (CO) reserve (CO increase from rest to peak exercise) was increased (5.7±2.9 L/min) 12 months after PEA compared with pre-PEA (2.5±1.8 L/min), p<0.0001. However, 12 months after PEA, the CO reserve was only 49% of that of healthy controls, p<0.0001. Changes in cardiac output (ΔCO), calculated as the difference between CO before PEA and 12 months later, were significantly correlated with six-minute-walk-test and peak oxygen uptake (VO2), both at rest and peak exercise. Figure 1 Conclusion Invasive exercise haemodynamic examination in CTEPH patients demonstrates that after otherwise successful PEA surgery, more than 50% of patients have a significant increase in exercise mPAP, and the CO reserve remains compromised 12 months after PEA. Improvement in physical capacity is correlated with ΔCO. Acknowledgement/Funding Danish Heart Foundation, Aarhus University, Arvid Nilssons Fond, Eva & Henry Frænkels Mindefond, and Snedkermester Sophus Hustru Astrid Jacobsens Fond