title: Clinical Study of Acute Vasoreactivity Testing in Patients with Chronic Thromboembolic Pulmonary Hypertension.
abstract: BACKGROUND
  The clinical significance of acute vasoreactivity testing (AVT) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains unclear. We analyzed changes in hemodynamics and oxygenation dynamics indices after AVT in patients with CTEPH using patients with pulmonary arterial hypertension (PAH) as controls.
  
  
  METHODS
  We analyzed retrospectively the results of AVT in 80 patients with PAH and 175 patients with CTEPH registered in the research database of Beijing Chao-Yang Hospital between October 2005 and August 2014. Demographic variables, cardiopulmonary indicators, and laboratory findings were compared in these two subgroups. A long-term follow-up was conducted in patients with CTEPH. Between-group comparisons were performed using the independent-sample t-test or the rank sum test, within-group comparisons were conducted using the paired t-test or the Wilcoxon signed-rank test, and count data were analyzed using the Chi-squared test. Survival was estimated using the Kaplan-Meier method and log-rank test.
  
  
  RESULTS
  The rates of positive response to AVT were similar in the CTEPH (25/175, 14.3%) and PAH (9/80, 11.3%) groups (P > 0.05). Factors significantly associated a positive response to AVT in the CTEPH group were level of N-terminal pro-brain natriuretic peptide (≤1131.000 ng/L), mean pulmonary arterial pressure (mPAP, ≤44.500 mmHg), pulmonary vascular resistance (PVR, ≤846.500 dyn·s-1·m-5), cardiac output (CO, ≥3.475 L/min), and mixed venous oxygen partial pressure (PvO2, ≥35.150 mmHg). Inhalation of iloprost resulted in similar changes in mean blood pressure, mPAP, PVR, systemic vascular resistance, CO, arterial oxygen saturation (SaO2), mixed venous oxygen saturation, partial pressure of oxygen in arterial blood (PaO2), PvO2, and intrapulmonary shunt (Qs/Qt) in the PAH and CTEPH groups (all P > 0.05). The survival time in patients with CTEPH with a negative response to AVT was somewhat shorter than that in AVT-responders although the difference was not statistically significant (χ2 =3.613, P = 0.057). The survival time of patients with CTEPH who received calcium channel blockers (CCBs) was longer than that in the group with only basic treatment and not shorter than that of patients who receiving targeted drugs or underwent pulmonary endarterectomy (PEA) although there was no significant difference between the four different treatment regimens (χ2 =3.069, P = 0.381).
  
  
  CONCLUSIONS
  The rates of positive response to AVT were similar in the CTEPH and PAH groups, and iloprost inhalation induced similar changes in hemodynamics and oxygenation dynamics indices. A positive response to AVT in the CTEPH group was significantly correlated with milder disease and better survival. Patients with CTEPH who cannot undergo PEA or receive targeted therapy but have a positive response to AVT might benefit from CCB treatment.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020; Department of Respiratory Medicine, Capital Medical University, Beijing 100069; Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233004, China.
authors.forename: Qi-Xia
authors.initials: QX
authors.lastname: Xu
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Yuan-Hua
authors.initials: YH
authors.lastname: Yang
authors.affiliation: Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233004, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Geng
authors.affiliation: Department of Respiratory and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.
authors.forename: Zhen-Guo
authors.initials: ZG
authors.lastname: Zhai
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Juan-Ni
authors.initials: JN
authors.lastname: Gong
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Li
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Tang
authors.affiliation: Department of Respiratory Medicine, Capital Medical University, Beijing 100069; Department of Respiratory and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029; National Clinical Research Center for Respiratory Diseases, Beijing 100730, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D062186:Arterial Pressure / Q000187:drug effects; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use; D004691:Endarterectomy; D065627:Familial Primary Pulmonary Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000503:physiopathology; D016285:Iloprost / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011498:Protein Precursors / Q000378:metabolism; D012189:Retrospective Studies; D012984:Software; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D002121:Calcium Channel Blockers; C099254:N-terminal proatrial natriuretic peptide; D011498:Protein Precursors; D014665:Vasodilator Agents; D009320:Atrial Natriuretic Factor; D016285:Iloprost