Diagnostic value of the six-minute walk test (6MWT) in grown-up congenital heart disease (GUCH): Comparison with clinical status and functional exercise capacity.
BACKGROUND
Exercise testing for the assessment of functional capacity plays an important role in long-term follow-up of GUCH patients. CPX is the favored modality for decision-making recommended in the current guidelines. In contrast to this complex method, the 6 MWT is a simple, easy-to-perform, safe, and commonly available exercise test. Although well-established in various cardiopulmonary diseases, the diagnostic impact of the 6 MWT in GUCH patients is not known so far.


METHODS
102 GUCH patients were evaluated by 6 MWT and CPX simultaneously. Clinical symptoms were assessed, according to the NYHA classification. Additionally, an echocardiography study, and selected cardiac blood tests (N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive Troponin T) were performed.


RESULTS
Ranges of six-minute walk distance (6 MWD) and peak oxygen consumption (peakVO2) were 116-765 m and 6.4-36.2 ml/kg/min, respectively. 6 MWD and peakVO2 showed a close correlation (r=0.72, 95% CI, 0.63 to 0.79). Patients with a peakVO2 of ≤ 15.5 ml/kg/min were excellently identified by 6 MWT (c-value=0.82). A cut-off value of 482 m was optimal to predict reduced peakVO2. In multivariate regression analysis, 6 MWD and NYHA class were identified as relevant predictors of peakVO2. In subgroup analysis, Eisenmenger patients achieved the shortest 6 MWD (280, SD 178 m).


CONCLUSIONS
In our study population of GUCH patients, the 6 MWD shows a close correlation to peakVO2, and an excellent prediction of reduced peakVO2. Thus, it seems to be an easy-to-perform and reliable screening parameter to evaluate functional capacity of these patients (Controlled Clinical Trials number, NCT02193243).
University Duesseldorf, Medical Faculty, Division of Cardiology, Pulmonology & Vascular Medicine, Germany. Electronic address: evakehmeier@t-online.de.
Eva S
ES
Kehmeier
University Duesseldorf, Medical Faculty, Division of Cardiology, Pulmonology & Vascular Medicine, Germany.
Margot H
MH
Sommer
University Duesseldorf, Medical Faculty, Division of Cardiology, Pulmonology & Vascular Medicine, Germany.
Anika
A
Galonska
University Duesseldorf, Medical Faculty, Division of Cardiology, Pulmonology & Vascular Medicine, Germany.
Tobias
T
Zeus
University Duesseldorf, Medical Faculty, Coordinating Centre for Clinical Trials, Germany.
Pablo
P
Verde
University Duesseldorf, Medical Faculty, Division of Cardiology, Pulmonology & Vascular Medicine, Germany.
Malte
M
Kelm
D000328:Adult; D018450:Disease Progression; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006304:Health Status; D006330:Heart Defects, Congenital / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D009017:Morbidity / Q000639:trends; D010101:Oxygen Consumption; D011379:Prognosis; D011446:Prospective Studies; D013997:Time Factors; D016138:Walking / Q000502:physiology*
Exercise testing; Grown-up congenital heart disease (GUCH); Peak oxygen consumption; Six minute walk test