title: Occlusion pressure analysis role in partitioning of pulmonary vascular resistance in CTEPH.
abstract: Flow-directed pulmonary artery occlusion is posited to enable partitioning of vascular resistance into small and large vessels. As such it may have a role in assessment for pulmonary endarterectomy. To test if the occlusion technique distinguished small from large vessel disease we studied 59 subjects with chronic thromboembolic pulmonary hypertension (CTEPH), idiopathic pulmonary arterial hypertension (IPAH), and connective tissue disease (CTD)-associated PAH. At right heart catheterisation, occlusion pressures were recorded. With fitting of the pressure decay curve, pulmonary vascular resistance was partitioned into downstream (small vessels) and upstream (large vessels, Rup). 47 patients completed the study; 14 operable CTEPH, 15 inoperable CTEPH, 13 idiopathic or CTD-PAH and five post-operative CTEPH. There was a significant difference in mean Rup in the proximal operable CTEPH group 87.3 (95% CI 84.1-90.5); inoperable CTEPH mean 75.8 (95% CI 66.76-84.73), p=0.048; and IPAH/CTD, mean 77.1 (95% CI 71.86-82.33), p=0.003. Receiver operating characteristic curves to distinguish operable from inoperable CTEPH demonstrated an area under the curve of 0.75, p=0.0001. A cut-off of 79.3 gave 100% sensitivity (95% CI 73.5-100%) but 57.1% specificity (95% CI 28.9-82.3%). In a subgroup analysis of multiple lobar sampling there was demonstrable heterogeneity. Rup is significantly increased in operable proximal CTEPH compared with non-operable distal CTEPH and IPAH/CTD-PAH. Rup variability in patients with CTEPH and PAH is suggestive of pathophysiological heterogeneity.
authors.affiliation: University of Cambridge, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Toshner
authors.forename: Jay
authors.initials: J
authors.lastname: Suntharalingam
authors.forename: Pierre
authors.initials: P
authors.lastname: Fesler
authors.forename: Elaine
authors.initials: E
authors.lastname: Soon
authors.forename: Karen K
authors.initials: KK
authors.lastname: Sheares
authors.forename: David
authors.initials: D
authors.lastname: Jenkins
authors.forename: Paul
authors.initials: P
authors.lastname: White
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Morrell
authors.forename: Robert
authors.initials: R
authors.lastname: Naeije
authors.forename: Joanna
authors.initials: J
authors.lastname: Pepke-Zaba
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D002908:Chronic Disease; D003240:Connective Tissue Diseases / Q000175:diagnosis / Q000503:physiopathology; D004691:Endarterectomy; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011651:Pulmonary Artery / Q000503:physiopathology / Q000601:surgery; D011655:Pulmonary Embolism / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D012372:ROC Curve; D014655:Vascular Resistance / Q000502:physiology*