One-minute sit-to-stand test in patients with pulmonary arterial hypertension associated with congenital heart disease: A single-center prospective study

BACKGROUND: Patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) have reduced exercise capacity. Recently, the 1-minute sit-to-stand test (1MSTST), which measures the number of repetitions from sitting to standing position in 1 minute, has been proposed as an alternative test to the 6-minute walking test (6MWT). The aim of our study was to assess the safety and results of the 1MSTST in comparison to the 6MWT in patients with PAH-CHD. METHODS: Consecutive adult patients with PAH-CHD underwent the 6MWT and the 1MSTST on the same day. The 6-minute walking distance in meters and the number of repetitions on the 1MSTST were measured. Heart rate, peripheral oxygen saturations, Borg dyspnea score, and lower limb fatigue were recorded before and immediately after testing. Correlations between both tests and clinical, laboratory, and imaging parameters were statistically analyzed. RESULTS: The study included 40 patients (50% female, mean age 43 ± 15 years), of whom 29 (72%) had Eisenmenger syndrome and 14 (35%) had Down syndrome. The number of 1MSTST repetitions correlated significantly with 6MWT distance (r = 0.807, p = 0.000). There were no adverse events, and the 1MSTST results correlated with the WHO functional class. Heart rate increase and oxygen desaturation after both tests correlated significantly, but less desaturation was observed after 1MSTST. CONCLUSIONS: Our study showed that the 1MSTST is a safe and easily applicable test in adult patients with PAH-CHD, including patients with Down syndrome. The results of the 1MSTST correlate significantly with the 6MWT, providing an alternative tool for exercise capacity assessment in patients with PAH-CHD.