Table 1.

Summary of studies evaluating the validity/reliability of eHealth for PAH

Author Country (year of publication)	Type of study/level of evidence (CEBM)/type of publication	Study population	Intervention	Summary of results	Significance level
Arelli et al USA (2012)37	Case-series/level 4/CP	18 patients with right heart catheterisation–confirmed PH	A portable IC device with real-time wireless monitoring via a Bluetooth adapter to determine HR, CO, CI and SV during the 6MWT	The IC increased the value of 6MWT and provided insight into the haemodynamic changes during exercise in PH	All the comparisons at rest vs activity were statistically significant (p<0.001)
Biederman et al USA (2015)28	Case-series study/level 4/CP	10 patients with PAH	Longitudinal CardioMEMS measuring of PAP, HR and CO and CMR at baseline and during pharmacological stress were performed	Cardiomems may contribute to providing an accurate calculation of non-invasive CO in PAH	NR
Brooks et al USA (2014, 2015)31 32	Case-series study/level 4/CP Prospective study/level 1b/JP	CP: 52 participants half of whom had CHF and PH JP: 103 participants with PH and CHF	SA-6MWT app for independent use at home	6MWTApp accurately predicted the distance walked during a 6MWT and It was easy to use and yielded accurate repeatable measurements in the clinic and at home	Good correlation with measured distance, r=0.89 (95% CI 0.82 to 0.95). For those with PAH, the r=0.75 (95% CI, 0.54 to 0.96) Home-based walked distance (SA-6MWTApp) were highly repeatable (CV=4.6%) and correlated with in-clinic-measured distance (r=0.88; 95% CI 0.87 to 0.89)
Fox et al Israel (2011, 2013)35 36	Case-series study/level 4/JP Prospective cohort study with good follow-up (>80%)/level 1b/JP	44 patients with PAH 86 subjects (52 with PH)	Step oximetry system linked to a computer	1. The step-oximetry test was an informative test of functional capacity among patients with PH. 2. Patients with PH showed significant limitation in step climbing ability that correlated with functional class and 6MWT	Correlation between 6MWT and step climbing velocity r=0.66 (p<0.0001) and O2 desaturation during step climbing correlated with DLCO (r=−0.65, p=0.003) Correlation between exercise performance on the step and 6MWT-climb index (r=−0.77, p<0.0001); saturation deviation on the step test correlated with diffusion capacity of the lung (r=−0.49, p=0.001)
Fruhwald et al Austria (2003)29	Case-series study/level 4/JP	5 patients with PAH who had received long-term treatment with aerosolized Iloprost	IHM in patients who had received long-term treatment with Iloprost	The IHM enabled reproducible measuring of drug-induced variations in PAP	Mean PAP from 68±13 to 49±11 mm Hg (mean time of 49±8 min). Thereafter, PAP returned to pre-inhalation levels
Gregorietti et al Argentina (2015 and 2016)33 34	Case-series study/level 4/CP	162 and 118 patients, respectively, with PH	Utilisation of a DP during the 6MWT, and its possible association with other parameters of clinical and prognostic relevance in PH	The addition of a DP to the 6MWT provided valuable data for evaluation and follow-up of patients with PH The number of footsteps was inversely correlated to clinical and laboratory parameters of prognostic relevance in PAH	In both studies, there were significant associations between pro-BNP levels and the number of footsteps (p=0.001) and WHO functional class (p=0.003 and p=0.009, respectively)
Tonelli et al USA (2013, 2014)38 39	Prospective cohort study with good follow-up (>80%)/level 1b/ CP and JP	43 subjects (28 with PH and 15 healthy controls) 50 subjects, 20 of them with PH	A portable impedance cardiography with wireless monitoring via a Bluetooth to determine HR and CO during a 6MWT and HR acceleration and decay slopes during the 6MWT	Wireless impedance cardiography showed lower distance walked, heart rate recovery (1 min) and CO change in PH under treatment than in healthy controls The HR acceleration and decay slopes during the 6MWT were different in PH, compared with other lung diseases and healthy controls	All the comparisons in HR curves and acceleration rates were statistically significant (p<0.001)

CEBM, Centre for Evidence-Based Medicine; CHF, congestive heart failure; CI, cardiac index; CMR, cardiovascular magnetic resonance; CO, cardiac output; CP, conference paper; CV, coefficient of variation; DLCO, diffusing capacity of the lungs for carbon monoxide; DP, digital pedometer; HR, heart rate; IC, impedance cardiography; IHM, implantable haemodynamic monitor; JP, journal paper; 6MWT, 6-minute walk test; 6MWTApp, 6-minute walk test app; NR, not reported; PAH, pulmonary arterial hypertension; PAP, positive airway pressure; PH, pulmonary hypertension; PVR, pulmonary vascular resistance; SV, stroke volume.