Clinical course of unoperated mild chronic thromboembolic pulmonary hypertension.

Background: Pulmonary endarterectomy is the treatment of choice for a majority of patients with chronic thromboembolic pulmonary hypertension (CTEPH), however, haemodynamic criteria for the surgery have not been established. It is still unknown whether patients with mild CTEPH should be operated on and what is the clinical course of unoperated, anticoagulated mild CTEPH.

Aim: To determine the clinical course in chronically anticoagulated, unoperated patients with mild CTEPH.

Methods: A single-centre, non-randomised, follow-up study involved 10 anticoagulated, unoperated patients (3 males and 7 females aged 46 to 77 years) with mild CTEPH (mean pulmonary artery pressure [MPAP] £ 30 mm Hg and pulmonary vascular resistance £ 300 dynes x s x cm(-5), ≥ 2 METs achieved during symptom limited treadmill exercise test) selected from 73 consecutive patients with CTEPH. The 3-year follow up included yearly echocardiographic evaluation of pulmonary artery systolic pressure (PASP), right ventricular end-diastolic diameter (RVEDD) and acceleration time (AcT) as well as NYHA functional class and symptom-limited treadmill exercise test.

Results: All the patients survived the 3-year follow-up. The PASP, RVEDD and AcT (mean ± SD) at baseline and at the end of follow-up were 43.9 ± 6.1 mm Hg and 25.6 ± 8.0 mm Hg, p = 0.0017, 25.4 ± 4.9 mm and 17.8 ± 3.82 mm, p = 0.00006, 68.3 ± 10.0 ms and 104.4 ± 16.48 ms, p = 0.0004, respectively. The NYHA functional class improved from 2.1 ± 0.32 to 1.3 ± 0.48, p = 0.002 and was accompanied by the trend to improve results of exercise test.

Conclusions: The results of the study suggest that patients with mild CTEPH can be treated successfully by anticoagulation alone with excellent 3-year survival rate, improved functional status and with gradual decrease of pulmonary pressure and right ventricular overload.