Incremental Shuttle Walking Test Distance and Autonomic Dysfunction Predict Survival in Pulmonary Arterial Hypertension

• Published in: The Journal of heart and lung transplantation
• Main Authors: Billings, Catherine G., PhD, Hurdman, Judith A., MD, Condliffe, Robin A., MD, Elliot, Charlie A., MD, Smith, Ian A., MSc, Austin, Matthew, BSc, Armstrong, Iain J., PhD, Hamilton, Neil, DPharm, Charalampopoulos, Athanasios, MD, Sabroe, Ian, PhD, Swift, Andrew J., PhD, Rothman, Alexander M., MD, Wild, Jim M., PhD, Lawrie, Allan, PhD, Waterhouse, Judith C., HNC, Kiely, David G., MD
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: Surgery; RAP; HRR1; HR; RHC; PVR; Six minute walking test; Right atrial pressure; exercise testing; ISWD; heart rate recovery; Kaplan-Meier; Pulmonary arterial hypertension; Incremental shuttle walking test distance; Pulmonary vascular resistance; Heart rate recovery at 1 minute; Incremental shuttle walking test; Right heart catheterisation; SBP; Systolic blood pressure; KM; ISWT; ISWD%pred; Percentage predicted incremental shuttle walking test distance; 6MWT; prognosis; Heart rate; PAH; autonomic function; Six minute walking test distance; 6MWD
• ISSN: 1053-2498
• DOI: 10.1016/j.healun.2017.04.008

Background To ensure effective monitoring of pulmonary arterial hypertension (PAH), a simple, reliable assessment of exercise capacity, applicable over a range of disease severity is needed. The study aim was to assess the ability of the incremental shuttle walking test (ISWT) to correlate with disease severity, measure sensitivity to change and predict survival in PAH. Methods 418 treatment-naïve patients with PAH, with baseline ISWT within 3 months of cardiac catheterization, were enrolled. The clinical validity and prognostic value of the ISWT distance was assessed at baseline and 1 year. Results ISWT distance was found to correlate at baseline with World Health Organisation functional class, Borg score and haemodynamics without a ceiling-effect (all p<0.001). Walking distance at baseline and after treatment predicted survival; the area under the receiver operator characteristic curve for the ability of the ISWD to predict mortality was 0.655 (95%CI 0.553-0,757), p=0.004 at baseline, and 0.737 (0.643-0.827), p<0.001 at 1 year following initiation of treatment. Change in ISWD also predicted survival (p=0.04). Heart rate (HR) and systolic blood pressure (SBP) parameters reflecting autonomic response to exercise (highest HR, change in HR, HR recovery at 1 minute>18, highest SBP, ΔSBP and 3minute SBP ratio) were significant predictors of survival (all p<0.05). Conclusions In patients with PAH the ISWT is simple to perform, allows assessment of maximal exercise capacity, is sensitive to treatment effect, predicts outcome and has no ceiling-effect. In addition, we have also shown that measures of autonomic function made post-exercise predict survival in PAH.