This page contains a Flash digital edition of a book.
PE/CTEPH: Link


The link between pulmonary embolism and CTEPH


Approximately 2–4% of people with pulmonary embolism develop CTEPH, which remains a relatively rare disease. This article discusses the link between the two conditions


George Giannakoulas MD Cardiology Department, AHEPA University Hospital, Aristotle University of Thessaloniki, Greece


Incomplete resolution of pulmonary embolism (PE) is not uncommon. In fact, despite effective therapeutic anticoagulation, more than 50% of patients have residual perfusion defects six months after diagnosis of PE.1 After 4.5 months of anticoagulation, residual pulmonary thromboemboli – as diagnosed with computed tomography (CT) angiography – persist in 26% of patients.2


Table 1: Reported incidence of CTEPH after PE First author, year n Marti et al, 20104 Dentali et al, 20095 Guerin et al, 20146 Pengo et al, 20047 Surie et al, 20108 Miniati et al, 20069


110 91


146 223 110


Becattini et al, 200610


Klok et al, 201011 Poli et al, 201012


320 259


866 239


A recent safety analysis of the Einstein PE study with an early CT scan at three weeks after the index PE episode showed that rivaroxaban resulted in complete clot resolution in 44% of the patients with acute PE, and in partial clot resolution in 45%; no relevant change was observed in 11%.3


Incidence of CTEPH 38


Chronic thromboembolic pulmonary hypertension (CTEPH) has been reported to be a long-term complication of PE. However, although there is a definite link between the two conditions, the true incidence of CTEPH after an episode of acute PE is currently unknown. There is a wide variation of reported frequencies (Table 1), which can be explained by differences in inclusion criteria and screening methods, as well as by the inherent difficulty of differentiating a true episode of acute PE from a superimposed acute PE on pre-existing CTEPH. The cumulative incidence of symptomatic


www.hospitalpharmacyeurope.com


Median follow-up (months) 24


NA 26


94.3 36


25.2 46


34 36


CTEPH was approximately 1%, 3% and 4% at six months, one year and two years, respectively, in a prospective study of 223 patients who presented with acute PE.7


In patients with a prior


episode of deep vein thrombosis the incidence was 5.2%, and 33% in patients with a prior episode of PE. However, up to one-quarter of patients of CTEPH have no known history of PE and, therefore, defining the true incidence of the disease remains a difficult task.13 This is the reason why CTEPH is often identified during diagnostic workup in patients with unexplained PH and an unremarkable past history of venous thromboembolism or PE. A history of acute PE is less common in patients with non-operable distal disease.14 The risk of developing CTEPH is increased in patients who have recurrent episodes of venous thromboembolism, large perfusion defects, younger age and echocardiographic signs of PH at the initial presentation. It is noteworthy that the normal right ventricle can maintain acutely a systolic arterial pressure of


RHC performed CTEPH prevalence (%) N N Y Y Y Y Y


9.1 8.8 4.8


3.8 at 2 years 2.7 1.3 0.8


Y Y


0.57 0.4


approximately 40mmHg. Therefore, whenever patients present with seemingly acute PE and echocardiographic signs of severe PH, CTEPH is likely already to have been present.


Pathophysiology


Non-resolving acute or recurrent episodes of PE are the most common causes of CTEPH. These thrombotic events may be symptomatic or silent. Perfusion defects on lung perfusion VQ scan appear identical for either PE or CTEPH and, therefore, differential diagnosis is practically impossible. However, with the use of CT pulmonary angiography, the defects in chronic disease usually have a different appearance from PE and require training to detect such differences.15


The pathway from acute PE to CTEPH encompasses the progression from acute thrombus, composed primarily of fibrin and erythrocytes, to organised obstructive fibrotic material and finally to precapillary PH. Although CTEPH has


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44