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.................................................................................................... 10.2.2 Clinical presentation and diagnosis Diagnosing CTEPH is difficult. Algorithms for predicting450 or ruling out CTEPH451,452 are limited by a lack of specificity. The clinical characteristics of patients enrolled in an international CTEPH registry have shown that the median age at diagnosis is 63 years and that both sexes are equally affected; paediatric cases are rare.447 Clinical symptoms and signs are non-specific or absent in early CTEPH, with signs of right heart failure only becoming evident in advanced disease. Thus, early diagnosis remains a challenge in CTEPH, with a median time of 14 months between symptom onset and diagnosis in expert centres.453 When present, the clinical symptoms of CTEPH may resemble those of acute PE or of pulmonary arterial hypertension; in the latter context, oedema and haemoptysis occur more often in CTEPH, while syncope is more common in pulmonary arterial hypertension.453

The diagnosis of CTEPH is based on findings obtained after at least 3 months of effective anticoagulation, to distinguish this condition from acute PE. The diagnosis requires a mean PAP of >_25 mmHg along with a pulmonary arterial wedge pressure of <_15 mmHg, documented at right heart catheterization in a patient with mismatched perfusion defects on V/Q lung scan. Specific diagnostic signs for CTEPH on multidetector CT angiography or conventional pulmonary cineangiography include ring-like stenoses, webs, slits, and chronic total occlusions.289 Some patients may present with normal pulmonary haemodynamics at rest despite symptomatic disease. If other causes of exercise limitation are excluded, these patients are considered as having chronic thromboembolic disease (CTED). Identification of patients with chronic thromboembolism without PH, who may have an indication for surgical or interventional treatment, requires particular expertise and should be done in CTEPH referral centres. Among 1019 patients who were submitted to pulmonary endarterectomy (PEA) in a UK referral centre, 42 patients did not have pulmonary hypertension at rest but showed functional improvement after the operation.454

Planar V/Q lung scan is a suitable first-line imaging modality for CTEPH as it has 9697% sensitivity and 9095% specificity for the diagnosis.455 SPECT seems less sensitive than planar V/Q scanning if assessed at a level of individual segmental arteries, but it is unlikely to miss clinically relevant CTEPH in an individual patient. In contrast to CTEPH, abnormal mismatched perfusion defects sometimes found in pulmonary arterial hypertension and pulmonary veno-occlusive disease typically have a non-segmental pattern. CTPA is gaining ground as a diagnostic modality in CTEPH,456 but it should not be used as a stand-alone test to exclude the disease.455 Newer diagnostic tests include dual-energy CT, which allows the simultaneous assessment of patency of the pulmonary arteries and of lung perfusion, probably at a cost of some increase in radiation delivered to the patient. Magnetic resonance imaging of the pulmonary vasculature is still considered inferior to CT.457 Cone-beam CT,458 angioscopy,459 intravascular ultrasound, and optical coherence tomography are more suitable for the characterization of lesions during interventional treatment than for diagnosis. High-resolution CT scan of the chest may assist in the differential diagnosis of CTEPH, showing emphysema, bronchial, or interstitial lung disease, as well as infarcts, and vascular and thoracic wall malformations. Perfusion inequalities manifesting as a mosaic parenchymal pattern are frequently found in CTEPH, but may also be observed in <_12% of patients with other causes of PH. Differential diagnosis of CTEPH should also include pulmonary arteritis, pulmonary angiosarcoma, tumour embolism, parasites (hydatid cyst), foreign body embolism, and congenital or acquired pulmonary artery stenoses.289

10.2.3 Surgical treatment Surgical PEA is the treatment of choice for operable CTEPH. In contrast to surgical embolectomy for acute PE, treatment of CTEPH

Table 13 Risk factors and predisposing conditions for chronic thromboembolic pulmonary hypertension447449

Findings related to the acute PE event (obtained at PE diagnosis) Concomitant chronic diseases and conditions predisposing to CTEPH (documented at PE diagnosis or at 36 month follow-up) Previous episodes of PE or DVT Ventriculo-atrial shunts Large pulmonary arterial thrombi on CTPA Infected chronic i.v. lines or pacemakers Echocardiographic signs of PH/RV dysfunctiona History of splenectomy CTPA findings suggestive of pre-existing chronic thromboembolic diseaseb Thrombophilic disorders, particularly antiphospholipid antibody syndrome and

high coagulation factor VIII levels Non-O blood group Hypothyroidism treated with thyroid hormones History of cancer Myeloproliferative disorders Inflammatory bowel disease Chronic osteomyelitis

CTEPH = Chronic thromboembolic pulmonary hypertension; CTPA = computed tomographic pulmonary angiography; DVT = deep vein thrombosis; i.v. = intravenous; LV = left ventricular; PE = pulmonary embolism; PH = pulmonary hypertension; RV = right ventricular. aEchocardiographic criteria of RV dysfunction are graphically presented in Figure 3, and their prognostic value summarized in Supplementary Data Table 3. On CTPA (fourchamber views of the heart), RV dysfunction is defined as RV/LV diameter ratio >1.0. bDirect and indirect vascular signs, as well as lung parenchymal findings, are summarized in Supplementary Data Table 2. Downloaded from academic.oup.com/eurheartj/article/41/4/543/5556136 by guest on 07 October 2026