Learning to pair therapies and the expanding matrix for pulmonary arterial hypertension: is more better?

2018 TSOC guideline focused update on diagnosis and treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized as a progressive and sustained increase in pulmonary vascular resistance, which may induce right ventricular failure. In 2014, the Working Group on Pulmonary Hypertension of the Taiwan Society of Cardiology (TSOC) conducted a review of data and developed a guideline for the management of PAH.⁴ In recent years, several advancements in diagnosis and treatment of PAH has occurred. Therefore, the Working Group on Pulmonary Hypertension of TSOC decided to come up with a focused update that addresses clinically important advances in PAH diagnosis and treatment. This 2018 focused update deals with: (1) the role of echocardiography in PAH; (2) new diagnostic algorithm for the evaluation of PAH; (3) comprehensive prognostic evaluation and risk assessment; (4) treatment goals and follow-up strategy; (5) updated PAH targeted therapy; (6) combination therapy and goal-orientated therapy; (7) updated treatment for PAH associated with congenital heart disease; (8) updated treatment for PAH associated with connective tissue disease; and (9) updated treatment for chronic thromboembolic pulmonary hypertension.

Remodeling of rat pulmonary artery induced by chronic smoking exposure

OBJECTIVE

To evaluate the dominant role in rat pulmonary artery (PA) remodeling induced by chronic smoking exposure (CSE).

METHODS

Thirty-five male Sprague-Dawley (SD) rats were exposed to 36 cigarettes per day, 6 days per week, for 1, 3, or 5 months. Another 35 SD rats were sham-exposed during the same period. Hemodynamic measurement, evaluation of the right ventricular hypertrophy index (RVHI) plus right ventricle-to-weight ratio, and hematoxylin eosin staining was performed. Wall thickness, artery radius, luminal area, and total area were measured morphometrically. Western blotting assessed expression of PPAR-γ BMP4, BMPR2, and TRPC1/4/6 in the artery and lung. Store-operated calcium entry (SOCE) and [Ca(2+)]i were measured using Fura-2 as dye.

RESULTS

Mean right ventricular pressure increased after 3 months of smoking exposure and continued to increase through 5 months. Right ventricular systolic pressure (RVSP) increased after 3 months of exposure and then stabilized. RVHI increased after 5 months; right ventricle-to-weight ratio was elevated after 3 months and further increased after 5 months. Wall thickness-to-radius ratio does-dependently increased after 3 months through 5 months, in parallel with the decreased luminal area/total area ratio after 5 months. Other changes included the development of inflammatory responses, enlargement of the alveolar spaces, and reductions in the endothelial lining of PAs, proliferative smooth muscle cells, fibroblasts, and adventitia. Moreover, BMP4 and TRPC1/4/6 expression increased to varying degrees in the arteries and lungs of smoking-exposed animals, whereas BMPR expression and SOCE increased only in the arteries, and PPAR-γ was downregulated in both the arteries and lungs.

CONCLUSIONS

In SD rats, smoking exposure induces pulmonary vascular remodeling. The consequences of increased SOCE include increase in TRPC1/4/6, probably via augmented BMP4 expression, which also contribute to inflammatory responses in the lung. Moreover, interactions between BMP4 and PPAR-γ may play a role in preventing inflammation under normal physiological conditions.

Imaging of the heart in pulmonary hypertension

Pulmonary hypertension (PH) is a disease of the pulmonary arteries resulting in a progressive increase in pulmonary vascular resistance, ultimately leading to right ventricular failure and death. It is a rare disease with a poor prognosis. The functional capacity of the right ventricle (RV) is a major prognostic determinant in PH. Our understanding of RV performance in PH has been hindered by the lack of techniques that give a reliable picture of right ventricular morphology and function. There have been recent major advances in our understanding of the mechanism of disease development, in the diagnostic process and in the treatment of PH. There are now three classes of medications that are effective in the treatment of PH: prostanoids, endothelin receptor antagonists and phosphodiesterase-5 inhibitors. Therapeutic advances in the management of PH have reinforced the requirement for non-invasive, accurate and reproducible methods of assessment to act as 'end-points' to measure the effects of treatment. It is our opinion that the most useful 'end-point' would be one that evaluates right heart morphology and function. We introduce and discuss the techniques currently used to image the heart in patients with PH. Imaging modalities discussed include echocardiography, radionuclide ventriculography, cardiac computed tomography and cardiac magnetic resonance (CMR) imaging focusing on the rapidly evolving technique of CMR imaging.

Pulmonary arterial hypertension: current therapeutic strategies

The treatment of pulmonary arterial hypertension--once a lethal condition--has evolved considerably over the past few years as the number of therapeutic options available to treat this disease has increased. In this Review we attempt to summarize the current knowledge of the pathogenesis of pulmonary hypertension, in relation to the therapies presently available and those that could become available in the near future. The use of prostacyclin and its analogs, calcium-channel blockers, endothelin-receptor antagonists and phosphodiesterase type 5 inhibitors is reviewed. Newer concepts, such as the use of combination therapy, and the potential for long-term disease amelioration and improvement of outcomes, are also discussed. The role of supportive care and medications not specific to pulmonary hypertension is also examined. In addition, we review the novel emerging therapies, such as imatinib, fasudil, simvastatin, ghrelin and vasoactive intestinal peptide, which hold therapeutic potential for disease modification as well as treatment of symptoms.