Maximal Exercise Testing Using the Incremental Shuttle Walking Test Can Be Used to Risk-Stratify Patients with Pulmonary Arterial Hypertension.

Robert A Lewis,Jim M Wild,Robin Condliffe,Allan Lawrie,Ian Sabroe,John Harrington,Andrew J Swift,David G Kiely,Neil Hamilton,Matthew Austin,Athanasios Charalampopoulos,A A Roger Thompson,Alexander Rothman ,Catherine Billings ,Charlie Elliot ,Jennifer T Middleton ,Judith Hurdman ,Abdul Hameed ,Iain Armstrong ,Ian Smith

doi:10.1513/annalsats.202005-423oc

Abstract

Rationale: Exercise capacity predicts mortality in pulmonary arterial hypertension (PAH), but limited data exist on the routine use of maximal exercise testing.Objectives: This study evaluates a simple-to-perform maximal test (the incremental shuttle walking test) and its use in risk stratification in PAH.Methods: Consecutive patients with pulmonary hypertension were identified from the ASPIRE (Assessing the Spectrum of Pulmonary hypertension Identified at a REferral centre) registry (2001–2018). Thresholds for levels of risk were identified at baseline and tested at follow-up, and their incorporation into current risk stratification approaches was assessed.Results: Of 4,524 treatment-naive patients with pulmonary hypertension who underwent maximal exercise testing, 1,847 patients had PAH. A stepwise reduction in 1-year mortality was seen between levels 1 (≤30 m; 32% mortality) and 7 (340–420 m; 1% mortality) with no mortality for levels 8–12 (≥430 m) in idiopathic and connective tissue disease–related PAH. Thresholds derived at baseline of ≤180 m (>10%; high risk), 190–330 m (5–10%; intermediate risk), and ≥340 m (<5%; low risk of 1-yr mortality) were applied at follow-up and also accurately identified levels of risk. Thresholds were incorporated into the REVEAL (Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management) 2.0 risk score calculator and French low-risk approach to risk stratification, and distinct categories of risk remained.Conclusions: We have demonstrated that maximal exercise testing in PAH stratifies mortality risk at baseline and follow-up. This study highlights the potential value of the incremental shuttle walking test as an alternative to the 6-minute walking test, combining some of the advantages of maximal exercise testing and maintaining the simplicity of a simple-to-perform field test.

Highlights

He Incremental Shuttle Walking Test The incremental shuttle walking test (ISWT) was undertaken as described by Singh et al [27], and as part of the standard patient evaluation
For the 6MWT it is recognised that younger patients with severe disease may walk low-risk distances of >500m, in the Incremental Shuttle Walking Test The ISWT was undertaken as described by Singh et al [27], and as part of the standard patient evaluation
Kaplan Meier analysis for ISWT distance (ISWD) in all forms of PH and for idiopathic pulmonary arterial hypertension (IPAH)/pulmonary arterial hypertension (PAH)-CTD at baseline are displayed in figure 1

Summary

Introduction

He Incremental Shuttle Walking Test The ISWT was undertaken as described by Singh et al [27], and as part of the standard patient evaluation. Patients complete a 10m length keeping in time to an external audible signal. The initial speed is a slow walk, 0.50m/s, increasing incrementally every level to a maximum of 2.37m/s at level 12. Each level takes one minute to complete and the test finishes at the end of level 12, a distance of 1020m. The patient continues until they are too breathless or unable to keep up with the required pace (see table 2 for details of walking speeds). Patients who were unable to perform an ISWT due to breathlessness were ascribed an ISWT distance of 0

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