Medical management of chronic thromboembolic pulmonary hypertension

The changing landscape of chronic thromboembolic pulmonary hypertension management

For patients with chronic thromboembolic pulmonary hypertension (CTEPH), the current standard of care involves surgical removal of fibro-thrombotic obstructions by pulmonary endarterectomy. While this approach has excellent outcomes, significant proportions of patients are not eligible for surgery or suffer from persistent/recurrent pulmonary hypertension after the procedure. The availability of balloon pulmonary angioplasty and the approval of the first medical therapy for use in CTEPH have significantly improved the outlook for patients ineligible for pulmonary endarterectomy. In this comprehensive review, we discuss the latest developments in the rapidly evolving field of CTEPH. These include improvements in imaging modalities and advances in surgical and interventional techniques, which have broadened the range of patients who may benefit from such procedures. The efficacy and safety of targeted medical therapies in CTEPH patients are also discussed, particularly the encouraging data from the recent MERIT-1 trial, which demonstrated the beneficial impact of using macitentan to treat patients with inoperable CTEPH, including those on background therapy. As the treatment options for CTEPH improve, hybrid management involving more than one intervention in the same patient may become a viable option in the near future.

Management of CTEPH is evolving rapidly, leading to improved patient outcomeshttp://ow.ly/rHrt30gUQWX

Macitentan for the treatment of inoperable chronic thromboembolic pulmonary hypertension (MERIT-1): results from the multicentre, phase 2, randomised, double-blind, placebo-controlled study

BACKGROUND

Macitentan is beneficial for long-term treatment of pulmonary arterial hypertension. The microvasculopathy of chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension are similar.

METHODS

The phase 2, double-blind, randomised, placebo-controlled MERIT-1 trial assessed macitentan in 80 patients with CTEPH adjudicated as inoperable. Patients identified as WHO functional class II-IV with a pulmonary vascular resistance (PVR) of at least 400 dyn·s/cm5 and a walk distance of 150-450 m in 6 min were randomly assigned (1:1), via an interactive voice/web response system, to receive oral macitentan (10 mg once a day) or placebo. Treatment with phosphodiesterase type-5 inhibitors and oral or inhaled prostanoids was permitted for WHO functional class III/IV patients. The primary endpoint was resting PVR at week 16, expressed as percentage of PVR measured at baseline. Analyses were done in all patients who were randomly assigned to treatment; safety analyses were done in all patients who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov, number NCT02021292.

FINDINGS

Between April 3, 2014, and March 17, 2016, we screened 186 patients for eligibility at 48 hospitals across 20 countries. Of these, 80 patients in 36 hospitals were randomly assigned to treatment (40 patients to macitentan, 40 patients to placebo). At week 16, geometric mean PVR decreased to 73·0% of baseline in the macitentan group and to 87·2% in the placebo group (geometric means ratio 0·84, 95% CI 0·70-0·99, p=0·041). The most common adverse events in the macitentan group were peripheral oedema (9 [23%] of 40 patients) and decreased haemoglobin (6 [15%]).

INTERPRETATION

In MERIT-1, macitentan significantly improved PVR in patients with inoperable CTEPH and was well tolerated.

FUNDING

Actelion Pharmaceuticals Ltd.

An epidemiological analysis of the burden of chronic thromboembolic pulmonary hypertension in the USA, Europe and Japan

Epidemiological data for chronic thromboembolic pulmonary hypertension (CTEPH) are limited and there are conflicting reports regarding its pathogenesis.

A literature review was conducted to identify CTEPH epidemiological data up to June 2014. Data were analysed to provide estimates of the incidence of CTEPH in the USA, Europe and Japan. An epidemiological projection model derived country-specific estimates of future incidence and diagnosis rates of CTEPH.

Overall, 25 publications and 14 databases provided quantitative epidemiological data. In the USA and Europe, the crude annual incidence of diagnosed pulmonary embolism and crude annual full (i.e. diagnosed and undiagnosed) incidence of CTEPH were 66–104 and 3–5 cases per 100 000 population, respectively, while in Japan these rates were lower at 6.7 and 1.9 per 100 000 population, respectively. In 2013, 7–29% of CTEPH cases in Europe and the USA were diagnosed, and the majority of patients were in New York Heart Association functional class III/IV at diagnosis. The projection model indicated that incidence of CTEPH will continue to increase over the next decade.

These data suggest that CTEPH is underdiagnosed and undertreated, and there is an urgent need to increase awareness of CTEPH. High-quality epidemiological studies are required to increase understanding of CTEPH.

Epidemiological data suggest that CTEPH is underdiagnosed and there is an urgent need to improve disease awarenesshttp://ow.ly/J0KC3095U2W