Usefulness of right-to-left shunting and poor exercise gas exchange for predicting prognosis in patients with pulmonary arterial hypertension.
We hypothesized that the longitudinal changes in peak oxygen uptake, ventilatory efficiency, and exercise-induced right-to-left shunting in patients with pulmonary arterial hypertension (PAH) would predict outcomes better than baseline measurements alone. Patients with PAH die prematurely. Identifying prognostic markers is critical for treating patients with PAH; however, longitudinal prognostic information of PAH is limited. We enrolled 103 patients with PAH into a long-term, prospective outcome study using serial cardiopulmonary exercise testing to measure the peak oxygen uptake, ventilatory efficiency (ratio of ventilation to carbon dioxide output at the anaerobic threshold), right-to-left shunting, and other factors in patients treated with optimal therapy. The patients were followed up for a mean of 4.7 years. During the study period, 20 patients died, and 3 underwent lung transplantation. The baseline peak oxygen uptake and ventilatory efficiency was 0.79 L/min and 49 (normal <34), respectively, reflecting severe disease. Poorer ventilatory efficiency and greater New York Heart Association classification were associated with poor outcome at baseline and at follow-up. On multivariate analysis, the persistence or development of an exercise-induced right-to-left shunt strongly predicted death or transplantation (p <0.0001), independent of the hemodynamics and all other exercise measures, including peak oxygen uptake and ventilatory efficiency. The absence of a shunt at baseline was associated with a 20% rate of nonsurvival, which decreased to 7% at follow-up. A poorer ventilatory efficiency appeared to be associated with a poor outcome in patients without a shunt. In conclusion, a persistent exercise-induced right-to-left shunt and poor ventilatory efficiency were highly predictive of poor outcomes in patients with pulmonary arterial hypertension.
Oudiz
Ronald J
RJ
Department of Medicine, Division of Cardiology, Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, CA, USA. roudiz@labiomed.org
Midde
Raghu
R
Hovenesyan
Arsen
A
Sun
Xing-Guo
XG
Roveran
Giorgio
G
Hansen
James E
JE
Wasserman
Karlman
K
D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011652:Pulmonary Circulation; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D011669:Pulmonary Wedge Pressure / Q000502:physiology*; D012720:Severity of Illness Index; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014481:United States / Q000453:epidemiology
Med Sci Sports Exerc. 2008 Oct;40(10):1725-32
18799981
Can Med Assoc J. 1985 Apr 15;132(8):919-23
3978515
Am J Cardiol. 2006 Jan 1;97(1):123-6
16377296
Chest. 1987 Mar;91(3):333-7
3816311
Circulation. 2002 Jul 16;106(3):319-24
12119247
J Am Coll Cardiol. 2009 Apr 28;53(17):1573-619
19389575
Thorax. 2000 Feb;55(2):95-6
10639523
Eur J Heart Fail. 2007 Sep;9(9):917-21
17707133
Eur Heart J. 2005 Sep;26(18):1895-902
15888496
Am J Cardiol. 1983 May 15;51(9):1560-1
6189385
J Am Coll Cardiol. 2009 Jun 30;54(1 Suppl):S43-S54
19555858
Circulation. 2002 Jan 1;105(1):54-60
11772876
Circulation. 2001 Jul 24;104(4):429-35
11468205
Eur Respir J. 2001 Apr;17(4):647-52
11401059
J Appl Physiol (1985). 1986 Jun;60(6):2020-7
3087938
Br Heart J. 1986 May;55(5):449-58
3707785
Chest. 2004 Sep;126(3):816-24
15364761
J Heart Lung Transplant. 2004 Jan;23(1):88-95
14734132