Introduction Pulmonary Embolism (PE) is a frequent diagnosis and the incidence of Chronic Thromboembolic pulmonary hypertension (CTEPH) after a single acute episode of PE is higher than expected – in one prospective long-term study 3.8% at 2 years (Pengo et al 2004). A diagnosis of CTEPH carries a 30% 5 year mortality and early diagnosis is vital if treatment is to be of success although successful treatment options remain limited.

We hypothesized that by following up all new diagnoses of PE we would pick up early cases of CTEPH and identify risk factors for those developing CTEPH. We also hypothesized that thrombolysis as per the BTS guidelines would reduce the subsequent incidence of CTEPH.

Methods A retrospective study of all patients referred to a PE clinic over a 2 year period was performed. Initial and follow up echocardiograms were examined, provoking factors and treatment identified with a primary end point of development of CTEPH at 2 years.

Results Of the first 50 patients presenting with an acute PE 12% (n=6) had evidence of CTEPH on echocardiogram after 2 years. The major risk factor for the development of CTEPH was an initial echocardiogram demonstrating a RVSP>50mmHg which conferred a 5-fold increase in persistent pulmonary hypertension on echocardiogram at 2 years (36% versus 7%).

None of the thrombolysed patients went on to develop CTEPH despite having in 50% an RVSP>50mmHg and all had a normal early (within six months) repeat echocardiogram.

Conclusions Patients who present with an acute PE and have an initial RVSP of >50mmHg on echocardiogram have a 5 fold increase in developing persistent pulmonary hypertension at 2 years. However patients who had a RVSP>50mmHg at diagnosis and are thrombolysed do not appear to develop CTEPH and have normal echocardiography at 2 years. Bearing in mind the mortality CTEPH carries and the difficulty in treating it, patients presenting with an acute significant PE and a RVSP>50mmHg should be considered for thrombolysis regardless of haemodynamic compromise.

Reference

1. Pengo V, Lensing AWA, Prins MH, et al., Incidence of chronic thromboembolic pulmonary hypertension after pulmonary embolism, N Engl J Med, 2004; 350:2257–64.