title: Right ventricular dysfunction in chronic thromboembolic obstruction of the pulmonary artery: a pressure-volume study using the conductance catheter.
abstract: Pressure-volume loops describe dynamic ventricular performance, relevant to patients with and at risk of pulmonary hypertension. We used conductance catheter-derived pressure-volume loops to measure right ventricular (RV) mechanics in patients with chronic thromboembolic pulmonary arterial obstruction at different stages of pathological adaptation. Resting conductance catheterization was performed in 24 patients: 10 with chronic thromboembolic pulmonary hypertension (CTEPH), 7 with chronic thromboembolic disease without pulmonary hypertension (CTED), and 7 controls. To assess the validity of conductance measurements, RV volumes were compared in a subset of 8 patients with contemporaneous cardiac magnetic resonance (CMR). Control, CTED, and CTEPH groups showed different pressure-volume loop morphology, most notable during systolic ejection. Prolonged diastolic relaxation was seen in patients with CTED and CTEPH [tau = 56.2 ± 6.7 (controls) vs. 69.7 ± 10.0 (CTED) vs. 67.9 ± 6.2 ms (CTEPH), P = 0.02]. Control and CTED groups had lower afterload (Ea) and contractility (Ees) compared with the CTEPH group (Ea = 0.30 ± 0.10 vs. 0.52 ± 0.24 vs. 1.92 ± 0.70 mmHg/ml, respectively, P < 0.001) (Ees = 0.44 ± 0.20 vs. 0.59 ± 0.15 vs. 1.13 ± 0.43 mmHg/ml, P < 0.01) with more efficient ventriculoarterial coupling (Ees/Ea = 1.46 ± 0.30 vs. 1.27 ± 0.36 vs. 0.60 ± 0.18, respectively, P < 0.001). Stroke volume assessed by CMR and conductance showed closest agreement (mean bias +9 ml, 95% CI -1 to +19 ml) compared with end-diastolic volume (+48 ml, -16 to 111 ml) and end-systolic volume (+37 ml, -21 to 94 ml). RV conductance catheterization detects novel alteration in pressure-volume loop morphology and delayed RV relaxation in CTED, which distinguish this group from controls. The observed agreement in stroke volume assessed by CMR and conductance suggests RV mechanics are usefully measured by conductance catheter in chronic thromboembolic obstruction.
authors.affiliation: Pulmonary Vascular Disease Unit, Papworth Hospital, Cambridge, United Kingdom;
authors.forename: Colm
authors.initials: C
authors.lastname: McCabe
authors.forename: Paul A
authors.initials: PA
authors.lastname: White
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hoole
authors.forename: Richard G
authors.initials: RG
authors.lastname: Axell
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Priest
authors.forename: Deepa
authors.initials: D
authors.lastname: Gopalan
authors.forename: Dolores
authors.initials: D
authors.lastname: Taboada
authors.forename: Robert
authors.initials: R
authors.lastname: MacKenzie Ross
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Morrell
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Shapiro
authors.forename: Joanna
authors.initials: J
authors.lastname: Pepke-Zaba
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure; D006328:Cardiac Catheterization; D016022:Case-Control Studies; D002407:Catheterization, Swan-Ganz; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000503:physiopathology*; D011655:Pulmonary Embolism / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D015203:Reproducibility of Results; D013318:Stroke Volume; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D016278:Ventricular Function, Right; D017725:Ventricular Pressure
keywords: chronic thromboembolism; diastolic dysfunction; pulmonary hypertension; right ventricle