Highlights from

ISTH 2020

The International Society of Thrombosis and Haemostasis

Virtual 12-14 July 2020

Less diagnostic delay in CTEPH diagnosis with novel algorithm

In the prospective, international InSHAPE II study, a non-invasive strategy for early identification of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism (PE) proved both accurate and cost-saving [1].

The diagnostic delay of CTEPH after acute PE is over 1 year and associated with increased mortality. Dr Gudula Boon (Leiden University Medical Center, the Netherlands) and her colleagues developed a non-invasive screening strategy comprising a 'CTEPH prediction score' and 'CTEPH rule-out criteria' aimed at diagnosing CTEPH earlier and limiting the number of required echocardiograms. "Six predictors [e.g. unprovoked PE, hypothyroidism, and diagnostic delay >2 weeks] have been identified that are highly probable for CTEPH and we included them in our score," Dr Boon explained. The CTEPH rule-out criteria were only applied on low-risk patients with a presence of CTEPH-specific symptoms. According to these criteria, patients with at least 1 ECG criteria and/or abnormal NT-proBNP values were referred to echocardiography. Included were 424 patients from 6 hospitals in the Netherlands, Poland, and Belgium. Of these participants, 69% were judged low-risk and 31% high-risk. Of all participants, 48% were low-risk patients without CTEPH-specific symptoms, and 21% were low-risk patients with symptoms.

Successful identification of almost all CTEPH patients The algorithm successfully ruled out 342 of 343 patients (see Figure). One missed case by the algorithm translates into a failure rate of 0.29%. "There was only 1 missed case who had persistent symptoms. However, this patient would also have been missed if echocardiography had been performed initially," Dr Boon explained. With the algorithm, CTEPH was diagnosed within 4 months after the index PE diagnosis, which is less diagnostic delay than the average. In addition, echocardiography was avoided in 81% of patients.

Figure: CTEPH screening algorithm applied at 3 months after diagnosis and 2-year follow-up results [1]

Figure- CTEPH screening algorithm applied

CTEPH, chronic thromboembolic pulmonary hypertension; ECG, electrocardiography; NT-proBNP, N-terminal pro-brain natriuretic peptide; PE, pulmonary embolism; PH, pulmonary hypertension; RHC, right heart catheterisation; RV, right ventricular.

Keywords: InSHAPE II, Chronic thromboembolic pulmonary hypertension, CTEPH, Pulmonary embolism, NT-proBNP

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