Severe Pulmonary Arteriopathy Is Associated with Persistent Hypoxemia after Pulmonary Endarterectomy in Chronic Thromboembolic Pulmonary Hypertension

PLoS One. 2016 Aug 29;11(8):e0161827. doi: 10.1371/journal.pone.0161827. eCollection 2016.

Abstract

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by occlusion of pulmonary arteries by organized chronic thrombi. Persistent hypoxemia and residual pulmonary hypertension (PH) following successful pulmonary endarterectomy (PEA) are clinically important problems; however, the underlying mechanisms remain unclear. We have previously reported that residual PH is closely related to severe pulmonary vascular remodeling and hypothesize that this arteriopathy might also be involved in impaired gas exchange. The purpose of this study was to evaluate the association between hypoxemia and pulmonary arteriopathy after PEA.

Methods and results: Between December 2011 and November 2014, 23 CTEPH patients underwent PEA and lung biopsy. The extent of pulmonary arteriopathy was quantified pathologically in lung biopsy specimens. We then analyzed the relationship between the severity of pulmonary arteriopathy and gas exchange after PEA. We observed that the severity of pulmonary arteriopathy was negatively correlated with postoperative and follow-up PaO2 (postoperative PaO2: r = -0.73, p = 0.0004; follow-up PaO2: r = -0.66, p = 0.001), but not with preoperative PaO2 (r = -0.373, p = 0.08). Multivariate analysis revealed that the obstruction ratio and patient age were determinants of PaO2 one month after PEA (R2 = 0.651, p = 0.00009). Furthermore, the obstruction ratio and improvement of pulmonary vascular resistance were determinants of PaO2 at follow-up (R2 = 0.545, p = 0.0002). Severe pulmonary arteriopathy might increase the alveolar-arterial oxygen difference and impair diffusion capacity, resulting in hypoxemia following PEA.

Conclusion: The severity of pulmonary arteriopathy was closely associated with postoperative and follow-up hypoxemia.

MeSH terms

  • Aged
  • Cardiac Catheterization
  • Endarterectomy*
  • Female
  • Humans
  • Hypertension, Pulmonary / blood*
  • Hypertension, Pulmonary / pathology*
  • Hypoxia / blood
  • Hypoxia / pathology
  • Male
  • Middle Aged
  • Oxygen / blood
  • Postoperative Period
  • Pulmonary Artery / pathology
  • Pulmonary Embolism / blood*
  • Pulmonary Embolism / pathology
  • Pulmonary Embolism / surgery
  • Vascular Resistance / physiology

Substances

  • Oxygen

Grants and funding

T.J was supported by The Cardiovascular Research Fund. N.T was supported by a research grant from the Ministry of Education, Culture, Sports, Science and Technology of Japan (25461148), and a grant from the Ministry of Health, Labour and Welfare specifically designated for the Respiratory Failure Research Group and Cardiovascular Diseases. S.S was supported by research grants from the Respiratory Failure Research Group from the Ministry of Health, Labour and Welfare, Japan, a grant to the Pulmonary Hypertension Research Group (No. 27280401) from the Japan Agency for Medical Research and Development, AMED, and a Grant-in-Aid for Scientific Research (JSPS KAKENHI Grant Number 15K09210) from the Japanese Ministry of Education and Science; K.I was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science; K.T was supported by Japanese Ministry of Health, Labour and Welfare research grants specifically designated for the Respiratory Failure Research Group and Cardiovascular Diseases. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.