Chronic kidney disease is associated with decreased exercise capacity and impaired ventilatory efficiency in heart transplantation patients.
OBJECTIVE
Chronic kidney disease (CKD) is common after heart transplantation (HTx). This study assessed the influence of CKD on exercise capacity and ventilatory efficiency after HTx.


METHODS
This cross-sectional study included 79 HTx patients (age 64 +/- 10 years, 66 men) at 8.1 +/- 4.3 years post-HTx who underwent maximal exercise testing, cardiac function assessment, and blood analysis. According to estimated glomerular filtration rate (eGFR, ml/min/1.73 m(2)), patients were categorized as having severe (Group 1, GFR < or = 30; n = 15), moderate (Group 2, GFR 30-60; n = 40), and mild (Group 3, GFR > 60; n = 24) renal impairment.


RESULTS
Patients in Group 1 were older, had lower peakVO(2) and impaired ventilatory efficiency compared with Groups 2 and 3 (all p < 0.05) Peak Watts, peak ventilation, and peak heart rate were lower in Group 1 compared with Group 3 (all p < 0.05). Exercise-derived variables did not differ significantly between Groups 2 and 3. GFR correlated with peakVO(2)/kg (r = 0.47; p < 0.01) and peak Watts (r = 0.34, p < 0.01). GFR (adjusted r(2) = 0.34), mean arterial pulmonary pressure, and age were the strongest independent predictors of peakVO(2). The proposed model explained 48% of variability in peakVO(2). By receiver operator characteristic analysis, eGFR was superior in distinguishing patients with impaired from those with preserved exercise capacity (peakVO(2) < 18 vs > 18 ml/kg/min).


CONCLUSIONS
Chronic KD after HTx is associated with impaired maximal exercise capacity and decreased ventilatory efficiency. GFR is a strong independent non-exercise-derived predictor of peak VO(2) in these patients.
Van Laethem
Christophe
C
Cardiovascular Center, Onze-Lieve-Vrouw Ziekenhuis, Aalst, Belgium. kine.van.laethem@telenet.be
Bartunek
Jozef
J
Goethals
Marc
M
Verstreken
Sofie
S
Walravens
Maarten
M
De Proft
Margot
M
Keppens
Chilla
C
Calders
Patrick
P
Vanderheyden
Marc
M
D000328:Adult; D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D016027:Heart Transplantation / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology*; D011379:Prognosis; D012372:ROC Curve; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000503:physiopathology*; D013223:Statistics as Topic
D010100:Oxygen