The relationship between preoperative clinical, respiratory, and hemodynamic parameters and the surgical anatomical classification of thrombi in patients with chronic thromboembolic pulmonary hypertension

This study we evaluated the association between preoperative clinical, respiratory, and hemodynamic parameters and the post-operative thrombus level in the pulmonary endarterectomy (PEA) material of patients with chronic thromboembolic pulmonary hypertension (CTEPH). Our hypothesis was that whether the level of thrombus is associated with preoperative pulmonary functions. To the best of our knowledge, this is the first study evaluating the relationship between anatomical classification of endarterectomy materials with clinical, respiratory, and hemodynamic parameters. This single-center retrospective cross-sectional study included patients aged 18 and older diagnosed with CTEPH who had PEA at Marmara University School of Medicine Hospital Istanbul between 2013 and 2022. A total of 150 patients with CTEPH who had PEA procedure. Patients whose degree of vascular involvement is unclear were excluded (n = 4). Patients whose post-operative pathology compatible other than thrombi (sarcoma, etc.) were excluded n = 3 (Fig. 2). Patients’ preoperative clinical parameters [New York Heart Association (NYHA) Functional Class (FC), 6-minute walk distance (6MWD)], PFTs, DLCO values, echocardiographic data and hemodynamic parameters measured with right heart catheterization were evaluated along with the thrombi levels of PEA specimens. The study included 143 patients diagnosed with CTEPH who had PEA. When the distribution of thrombus materials was examined according to anatomical classification; 18.9% of patients (n = 27) were classified as Level 1 (main branch), 40.6% as Level 2 (lobar) (n = 58), 32.2% as Level 3 (segmental) (n = 46), and 8.4% as Level 4 (subsegmental) (n = 12). The mean values of predicted FEV1 (forced expiratory volume in 1 s) were 2.05 ± 0.55 L (liters) for patients with Level 1 thrombus, 2.29 ± 0.95 L for Level 2, 2.10 ± 0.76 L for Level 3, and 2.86 ± 1.33 L for Level 4 (p = 0.053). The DLCOcSB (carbon monoxide diffusion capacity corrected for alveolar volume) values were %60.38 ± 28.98 for patients with Level 1 thrombus, %65.88 ± 20.85 for Level-2, %65.29 ± 18.32 for Level-3, and %85 ± 21.42 for Level-4 (p = 0.07). Cardiac indices (L/min/m²) were 2.46 ± 0.84 for Level 1, 2.43 ± 1.14 for Level 2, 2.42 ± 0.76 for Level 3, and 3.04 ± 0.63 for Level 4 (p = 0.02). No relationship was observed between the anatomical level of thrombus and 6MWD and the hemodynamic data measured via RHC except cardiac indices (all p values > 0.05). Our study did not find a significant relationship between the preoperative parameters of PFTs, DLCO values, and hemodynamic parameters excluding cardiac index with the anatomical classification of thrombi in patients who had PEA for CTEPH. To the best of our knowledge, this is the first study evaluating the relationship between anatomical classification of endarterectomy materials with clinical, respiratory, and hemodynamic parameters.