Knowledge of the structure and function of pulmonary circulation has evolved considerably in the last few decades. The use of non-invasive imaging techniques to assess the anatomy and function of the pulmonary vessels and heart has taken on added importance with the recent advent of novel therapies. Imaging findings not only constitute a diagnostic tool but have also proven to be essential for prognosis and treatment follow-up. This article reviews the myriad of imaging methods currently available for the assessment of pulmonary circulation, from the simple chest X-ray to techniques that are more complex and promising, such as electrical impedance tomography.

Keywords: Pulmonary circulation; Diagnostic imaging; Hypertension, pulmonary.

Chronic thromboembolic pulmonary hypertension is the only potentially curable form of pulmonary hypertension, assuming that surgical treatment is possible. However, there are hindrances to making a definitive, noninvasive diagnosis. We present the case of a 40-year-old female patient with idiopathic pulmonary arterial hypertension, confirmed in 1994. This patient developed thrombi in pulmonary vessels (as an overlap syndrome) mimicking chronic thromboembolic pulmonary hypertension. The identification of these conditions, which present high intraoperative mortality and unsatisfactory surgical resolution, is quite difficult in clinical practice. We discuss the current approach to candidate selection for surgical treatment of chronic thromboembolic pulmonary hypertension and the possible repercussions of inappropriate selection.

Keywords: Hypertension, pulmonary/diagnosis; Hypertension, pulmonary/therapy; Pulmonary embolism; Endarterectomy.

Objective: To develop and validate a protocol for the treadmill six-minute walk test (tread6MWT) to evaluate patients with pulmonary arterial hypertension (PAH). Methods: The study population comprised 73 patients with PAH, diagnosed by means of right heart catheterization, with or without NO inhalation. All patients performed a hallway 6MWT and three tread6MWTs based on a pre-determined incremental speed protocol and interposed by a rest period. The patients who had been submitted to hemodynamic testing using NO performed the third tread6MWT while inhaling the same dose of NO that had been used during the catheterization. Results: We found that the treadmill six-minute walk distance (tread6MWD) correlated with hemodynamic data, functional class and the hallway six-minute walk distance (6MWD). In addition, the tread6MWD correlated significantly with survival, thereby confirming the correlation with disease severity. Inhalation of NO during the tread6MWT led to variations that were consistent with the hemodynamic changes induced by the same dose of inhaled NO, suggesting that the protocol developed can reflect the effect of therapeutic interventions. Conclusions: We conclude that the tread6MWD is a useful prognostic and functional marker for the routine evaluation of PAH patients.

Keywords: Hypertension, pulmonary; Exercise test; Hemodynamics.