Abstract Background Chronic thromboembolic pulmonary hypertension (CTEPH) represents a rare but serious sequela of acute pulmonary embolism. The primary treatment for CTEPH is surgical pulmonary endarterectomy (PEA), which in adequate selected cases leads to a permanent improvement in pulmonary hemodynamics. We have developed an experimental method based on pressure-volume (PV) loops to characterize RV-pulmonary vascular interaction in pulmonary hypertension PH patients. This method applies pulmonary artery (PA) pressure-volume loops, derived from pressure and volume tracings at the PA level, obtained through right heart catheterization (RHC) and cardiac magnetic resonance (CMR). As CTEPH typically behaves like an on/off phenomenon of PH before and after, it provides an ideal setting to study the feasibility of our diagnostic approach as a follow-up tool for monitoring changes in pulmonary haemodynamics (i.e. normalization vs persistent post-PEA pulmonary hypertension if vascular impairment remains despite surgery). Purpose To determine whether our method can detect changes in pulmonary dynamics in patients undergoing PEA by combining RHC and CMR imaging data. Methods 19 patients with CTEPH (9 women, aged 63.16±14.68 years, BMI 27.52±4.33 kg.m2) who underwent PEA in single centre. Preoperative evaluation included RHC for pulmonary pressure tracings and CMR with phase-contrast sequence for flow tracings at the level of the main PA to codify volume-pressure loops. Six months post-PEA, RHC and CMR were repeated to reevaluate pulmonary hemodynamics and PA flow, along with right ventricle (RV) performance by end-systolic (iRVESV) and end-diastolic volumes (iRVEDV), RV ejection fraction and RV mass. Results Globally, post-PEA status showed significantly improvement in mPAP (21.53±8.95 vs. 36.47±10.22 mmHg; p0,001), iPVR (483.51±263.56 vs. 1042,81±510.55 dynes.s.cm-5.m2; p0,001) and RV ejection fraction (51,92%±8,46 vs. 41,68%±12,42; p=0,008). Overall, pressure-volume loops shifted from the steeper pre-PEA shape to shallower post-PEA form (Figure 1), consistent with the hemodynamic improvement observed in RHC. More interestingly, 5 patients with persistent post-PEA pulmonary hypertension showed no significant changes in post-PEA pressure-volume loops (cases 10, 12, 14, 15 and 17). Compared to patients who normalized pressure-volume loops, these 5 patients exhibited lower improvement in pulmonary hemodynamics and RV performance. Conclusion Volume-pressure loops at the level of the main PA is able to differentiate pulmonary hemodynamic status in patients undergoing PEA, which opens the door to using this tool to better characterize and follow patients with chronic PH.Difference between postPEA loop changes
Palacios-Echavarren et al. (Sat,) studied this question.