Incremental Shuttle Walking Test Distance Is Reduced in Patients With Pulmonary Hypertension in World Health Organisation Functional Class I

Abstract

Background: There is increasing interest in screening for and diagnosing pulmonary hypertension earlier in the course of disease. However, there is limited data on cardiopulmonary abnormalities in patients with pulmonary hypertension newly diagnosed in World Health Organization Function Class (WHO FC) I.Methods: Data were retrieved from the ASPIRE registry (Assessing the Spectrum of Pulmonary hypertension Identified at a REferral center) for consecutive treatment naïve patients diagnosed with pulmonary hypertension by cardiac catheterization between 2001 and 2010 who underwent incremental shuttle walk exercise testing.Results: Eight hundred and ninety-five patients were diagnosed with Group 1-5 pulmonary hypertension. Despite the absence of symptoms, patients in WHO FC I (n = 9) had a significant reduction in exercise capacity (Incremental shuttle walk distance percent predicted (ISWD%pred) 65 ± 13%, Z score −1.77 ± 1.05), and modest pulmonary hypertension with a median (interquartile range) pulmonary artery pressure 31(20) mmHg and pulmonary vascular resistance 2.1(8.2) Wood Units, despite a normal diffusion of carbon monoxide adjusted for age and sex (DLco)%pred 99 ± 40%. Compared to patients in WHO FC I, patients in WHO FC II (n = 162) had a lower ISWD%pred 43 ± 22 and lower DLco%pred 65 ± 21%.Conclusion: Our results demonstrate that patients with newly diagnosed pulmonary hypertension with no or minimal symptomatic limitation have a significant reduction of exercise capacity.

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

“…We have previously shown that as an alternative but maximal field walking test, the ISWT provides a measure of maximal exercise capacity without a ceiling effect and can identify exercise limitation in asymptomatic patients diagnosed with pulmonary hypertension in World Health Organization functional class I ( 20 , 33 ). Using data from the present study, we have now identified that maximal exercise testing using the ISWT can risk-stratify patients with IPAH and PAH-CTD.…”

Risk assessment and real-world outcomes in chronic thromboembolic pulmonary hypertension: insights from a UK pulmonary hypertension referral service

“…33 Previously published thresholds for the ISWT were used. [33][34][35] Each variable was graded from 1 to 3 (1=low risk, 2=intermediate risk and 3=high risk). A mean grade was calculated and rounded to the nearest integer to determine the risk group.…”

Screening strategies for pulmonary arterial hypertension

“…However, a normal DL CO does not exclude a diagnosis, particularly in patients with FPAH/HPAH where DL CO can be preserved 1 . A recent study evaluating cardiopulmonary abnormalities in newly diagnosed patients with pulmonary hypertension demonstrated that abnormalities of DL CO correlated with World Health Organization (WHO) functional class (FC) although reductions in exercise capacity were more sensitive than DL CO for the detection of pulmonary hypertension in asymptomatic patients in WHO FC I 48 . A parameter calculated from pulmonary function tests (PFTs) is the forced vital capacity/DL CO ratio (both expressed as percentage of the predicted values).…”

“…Although CPET provides a large amount of physiological information it is time-consuming to perform and requires significant expertise, meaning its deployment is limited to carefully selected at-risk groups. A study of 895 patients with Group 1 to Group 5 PH demonstrated that 89% of asymptomatic (WHO FC I) patients, 93% of patients with mild breathlessness (WHO FC II), and 100% of patients in WHO FC III and IV walked <80% of their predicted exercise capacity using an incremental field walking test (incremental shuttle walking test); this test would be more suited to screening large populations 48 …”