P1343Risk factors for chronic thromboembolic pulmonary hypertension - importance of thyroid disease and treatment

Abstract

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease and believed to result from an impaired thrombus resolution after pulmonary embolism (PE). Additionally, a number of further risk factors including thyroid disease have been described to be associated with CTEPH. Purpose: To investigate the prevalence of risk factors with a special focus on thyroid disease in patients with CTEPH. Methods: Patients with operable CTEPH treated with pulmonary endarterectomy (PEA; alone or combined with balloon pulmonary angioplasty [BPA]) at a single referral centre for PEA surgery between 01/2014 and 12/2015 were included in the present analysis. In a subgroup of patients, TSH, fT3, fT4 and TPO antibodies were measured in venous blood samples taken before PEA. Thyroidal function was classified as euthyroidism, hypothyroidism (hypo) or hyperthyroidism (hyper) based on medical history and laboratory findings. Results: Overall, 237 patients (median age, 62 [IQR, 52‐72] years; 46.0% female; NYHA class III/IV, 78.5%; mean PA pressure, 43 [34‐50] mmHg) were studied. Interestingly, almost all patients reported a history of venous thromboembolism (VTE, n=217; 91.6%); of those, the majority had a PE (n=203; 85.7%) and as many as 78 patients (32.9%) more than one PE event. Overall, 46 patients (19.4%) had a known thrombophilia and 24 patients (10.1%) a chronic systemic inflammatory disease. Risk factors are shown and compared to previous cohort study findings in Figure 1. Overall, 55 patients (23.2%) had a known thyroid disease (hypo: n=43, 18.1%; hyper: n=12, 5.1%) and of those, 50 patients (90.9%) received specific treatment (80% levothyroxine, median dosage, 88 [75‐125] mg/d; 12% thyroid suppression therapy; 8% iodine). Laboratory measurements performed in 122 patients (51.5%) identified further 10 patients with subclinical hypo and 1 patient with subclinical hyper (in total, 66 patients [27.8%] with thyroid disease). Median level of TSH was 0.9 (1.6‐2.6) μU/ml, of fT3 2.6 (2.8‐3.0) pg/ml and of fT4 1.0 (1.0‐1.2) ng/dl; thus, at the moment of blood sampling, 12 patients (9.8%) were identified with thyroidal dysfunction (hypo in 7 and hyper in 5 patients). Elevated levels ≥5.61 IU/ml of TPO antibodies were found in 19 patients (15.6%; median, 52.5 [19.8‐95] IU/ml); of those, 7 patients (36.8%) had thyroidal dysfunction. fT4 levels correlated weakly with cardiac output (r=‐0.191; p=0.039) and were higher in patients who died in‐hospital (1.4 [1.2‐1.5] vs 1.1 [1.0‐1.2] ng/dl; p=0.037) or during follow‐up (1.4 [1.1‐1.6] vs 1.1 [1.0‐1.6] ng/ml; p=0.016). However, thyroid disease / dysfunction or specific treatment was not associated with outcomes. Conclusion: In 237 operable CTEPH patients, a history of VTE and thyroid disease were more common than previously reported. fT4 levels were higher in patients who died in‐hospital or during long‐term follow‐up; however, thyroid disease / dysfunction was not associated with outcomes. (Figure Presented).