Chronic Thromboembolic Pulmonary Hypertension: An Update

Abstract

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease observed in a small proportion of patients after acute pulmonary embolism (PE). CTEPH has a high morbidity and mortality rate, related to the PH severity, and a poor prognosis, which mirrors the right ventricular dysfunction involvement. Pulmonary endarterectomy (PEA) reduces pulmonary vascular resistance, making it the treatment of choice and should be offered to operable CTEPH patients, as significant symptomatic and prognostic improvement has been observed. Moreover, these patients may also benefit from the advances made in surgical techniques and pulmonary hypertension-specific medication. However, not all patients are eligible for PEA surgery, as some have either distal pulmonary vascular obstruction and/or significant comorbidities. Therefore, surgical candidates should be carefully selected by an interprofessional team in expert centers. This review aims at making an overview of the risk factors and latest developments in diagnostic tools and treatment options for CTEPH.

Keywords: chronic thromboembolic pulmonary hypertension (CTEPH); chronic thromboembolism; idiopathic pulmonary arterial hypertension (IPAH); pulmonary artery pressure (PAP); pulmonary thromboendarterectomy; pulmonary vasodilator therapy.

Figure 1

(A) Axial images from a pulmonary angio-CT demonstrating the presence of bands within the vascular lumen (arrow) and (B) a focal vascular stenosis secondary to an eccentrically located thrombus (arrow), due to incomplete thrombus resolution. (C) HRTC showing a diffuse mosaic pattern of perfusion (*), a typical radiological finding in chronic pulmonary thromboembolism.

Figure 2

(A) Right cardiac catheterization in a CTEPH patient, not a candidate for surgical treatment due to the involvement of the distal pulmonary arteries (technically inaccessible), before treatment (as reported in the table at right PVR 480 dynes/s/cm (-5)), * software evaluation. From below: pulmonary arterial pressure, respiratory, and ECG waveforms during arterial catheterization. The first part of the pressure trace reflects the pressure in a pulmonary artery (large swings, dicrotic notch). Then, the balloon is inflated, and the tip of the Swan Ganz catheter floats until it wedges in a small artery (small swings synchronous with respiratory rate). This provides a pulmonary arterial wedge pressure (PAWP), i.e., an indirect measure of the pressure in the left ventricle. (B) Right cardiac catheterization in the same patient after three months of treatment with riociguat as per data sheet (as reported in the table at right PVR 418 dynes/s/cm (-5)).

Figure 2

(A) Right cardiac catheterization in a CTEPH patient, not a candidate for surgical treatment due to the involvement of the distal pulmonary arteries (technically inaccessible), before treatment (as reported in the table at right PVR 480 dynes/s/cm (-5)), * software evaluation. From below: pulmonary arterial pressure, respiratory, and ECG waveforms during arterial catheterization. The first part of the pressure trace reflects the pressure in a pulmonary artery (large swings, dicrotic notch). Then, the balloon is inflated, and the tip of the Swan Ganz catheter floats until it wedges in a small artery (small swings synchronous with respiratory rate). This provides a pulmonary arterial wedge pressure (PAWP), i.e., an indirect measure of the pressure in the left ventricle. (B) Right cardiac catheterization in the same patient after three months of treatment with riociguat as per data sheet (as reported in the table at right PVR 418 dynes/s/cm (-5)).

Figure 3

Pulmonary endarterectomy casts from a patient with complex and severe CTEPH.