According to a new study, treatment of pulmonary arterial hypertension (PAH) in patients younger than 55 years significantly improves their performance on the 6-minute walk test (6MWT). However, the same treatment in older patients was found to be associated with disease stabilisation and sometimes deterioration. The findings have been published in Heart, Lung and Circulation.
The researchers point out that the study findings indicate the need to treat PAH as early in the disease course as possible. Nicholas Collins, (John Hunter Hospital, New Lambton, New South Wales, Australia) and colleagues comment, "“This difference in benefit may be the result of more advanced disease at the time of diagnosis with advanced histopathological changes within the pulmonary vasculature affecting the efficacy of available therapy. This reinforces the need to aggressively investigate dyspnoea to permit appropriately early detection and initiation of therapy.”
The study included a review of 119 patients who had been treated with PAH-specific therapies including endothelin receptor antagonists, phosphodiesterase inhibitors or prostanoids. The patients were followed for a maximum period of 8 years, undertook the 6MWT and received transthoracic echocardiography every six months.
The findings of the study showed that in the group of patients with a mean age of 65 years, age affected the results of the 6MWT quite significantly. This was true even after adjusting for confounders such as smoking, gender and warfarin use. Each year older a patient was at the time of entry into the study, the patient was associated with a 5 metre greater decline in 6MWT distance over the following year.
The researchers also found that patients younger than 55 years had a significant improvement in 6MWT distance over time. 22 patients over the age of 55 experienced stabilisation or a slight decline in 6MWT distance. In addition, age at the start of therapy was associated with a greater rate of decline in 6MWT over follow-up. However, no significant difference was observed between age group over 55 year as compared with baseline.
The authors of the study feel that these findings can help clinicians better understand the natural course of PAH with age and this can help them make changes or additions to therapy. They also explain that decline in 6MWT distance has been used as a tool to identify therapeutic failure and has been used to determine escalation for treatment. The authors note that their findings are in contradiction with historical data as it shows only a modest decline in function in older patients. Therefore, this study suggests that age is not the only factor that should be used as exclusion to treatment.
Source: Heart, Lung, Circulation
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