Prognostic and pathophysiological marker for patients with chronic thromboembolic pulmonary hypertension: Usefulness of diffusing capacity for carbon monoxide at diagnosis.
Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive disease in some patients, despite improved treatments. Microvasculopathy has been implicated in the poor outcomes of patients with CTEPH. A reduction in the diffusing capacity for carbon monoxide (DLCO) was previously suggested to indicate microvasculopathy in CTEPH patients; therefore, we assessed DLCO/alveolar ventilation (DLCO/VA) as a prognostic and pathophysiological marker in CTEPH.



We performed a retrospective cohort study of 214 CTEPH patients consecutively diagnosed between 1986 and 2011. After exclusion of 24 patients because of missing DLCOdata or severe obstructive impairment, the mortality rates of medically treated patients classified with normal or decreased DLCOvalues were compared, and prognostic factors were determined. The relationship between long-term surgical outcomes and DLCO/VAwas also investigated.



Ninety-one inoperable patients were treated medically, two of whom underwent balloon pulmonary angioplasty. Ninety-nine underwent pulmonary endarterectomy. The 5-year survival rate of medically treated patients was significantly lower in patients with decreased DLCO/VAthan in those with normal values (61.4% vs 90.4%, P = 0.017). Decreased preoperative DLCO/VAwas associated with a smaller percent decrease in post-operative pulmonary vascular resistance, but not with the extent of proximal thrombi; these results may support our hypothesis that DLCOreflects microvascular involvement.



Decreased DLCO/VAwas associated with poor outcomes of medically treated CTEPH patients; and may be useful for identifying high-risk patients, potentially leading to earlier and more appropriate interventions.
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Rika
R
Suda
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.|Department of Advanced Medicine in Pulmonary Hypertension, Graduate School of Medicine, Chiba University, Chiba, Japan.
Nobuhiro
N
Tanabe
Department of Cardiovascular Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
Keiichi
K
Ishida
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Fumiaki
F
Kato
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Takashi
T
Urushibara
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.|Department of Advanced Medicine in Pulmonary Hypertension, Graduate School of Medicine, Chiba University, Chiba, Japan.
Ayumi
A
Sekine
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.|Department of Advanced Medicine in Pulmonary Hypertension, Graduate School of Medicine, Chiba University, Chiba, Japan.
Rintaro
R
Nishimura
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.|Department of Advanced Medicine in Pulmonary Hypertension, Graduate School of Medicine, Chiba University, Chiba, Japan.
Takayuki
T
Jujo
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Toshihiko
T
Sugiura
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Ayako
A
Shigeta
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Seiichiro
S
Sakao
Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Koichiro
K
Tatsumi
D000800:Angioplasty, Balloon / Q000379:methods / Q000706:statistics & numerical data; D015415:Biomarkers / Q000032:analysis; D002248:Carbon Monoxide / Q000032:analysis*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D007564:Japan / Q000453:epidemiology; D008168:Lung / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D055806:Microvessels; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D011379:Prognosis; D011651:Pulmonary Artery / Q000601:surgery; D011653:Pulmonary Diffusing Capacity; D011655:Pulmonary Embolism / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D011659:Pulmonary Gas Exchange; D012129:Respiratory Function Tests / Q000379:methods; D012189:Retrospective Studies; D015996:Survival Rate
D015415:Biomarkers; D002248:Carbon Monoxide
chronic thromboembolic pulmonary hypertension; pulmonary diffusing capacity; pulmonary embolism; pulmonary function tests; pulmonary hypertension