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Impact of differential right‐to‐left shunting on systemic perfusion in pulmonary arterial hypertension
Author(s) -
Weimar Timo,
Watanabe Yoshiyuki,
Kazui Toshinobu,
Lee Urvi S.,
Montecalvo Alessandro,
Schuessler Richard B.,
Moon Marc R.
Publication year - 2013
Publication title -
catheterization and cardiovascular interventions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 116
eISSN - 1522-726X
pISSN - 1522-1946
DOI - 10.1002/ccd.24458
Subject(s) - medicine , shunt (medical) , cardiology , pulmonary hypertension , pulmonary artery , cardiac output , shunting , hemodynamics , anesthesia
Objectives This study aimed at identifying the ideal right‐to‐left shunt‐fraction to improve cardiac output (CO) and systemic perfusion in pulmonary arterial hypertension (PHT). Background Atrial septostomy (AS) has been a high‐risk therapeutic option for symptomatic drug‐refractory patients with PHT. Results have been unpredictable due to limited knowledge of the optimal shunt‐quantity. Methods In nine dogs, an 8‐mm shunt‐prosthesis was inserted between the superior vena cava (SVC) and the left atrium. With pulmonary artery (PA) banding, mean (±SEM) systolic right ventricular pressure increased from 37 ± 1 mm Hg at baseline to 44 ± 1 mm Hg (moderate PHT, P = 0.005) and 50 ± 2 mm Hg (severe PHT, P < 0.001). Shunt‐flow was adjusted by total (forcing all flow through the shunt) or partial occlusion of the SVC and partial or total clamping of the shunt. Caval‐, shunt‐, and aortic‐flow were measured by ultrasonic flow‐probes. Blood gases were drawn from the aortic root and PA. Results At severe PHT, a shunt‐flow of 11 ± 1% of CO (253 ± 90 mL/min) increased CO significantly by 25% (1.8 ± 0.1 to 2.4 ± 0.2 L/min, P = 0.005) causing an increase of systemic oxygen delivery index (DO 2 I) by 23% (309 ± 23 to 399 ± 32 mL/min/m 2 , P = 0.035). Arterial O 2 ‐saturation did not change significantly until a shunt‐flow of 18 ± 2% was exceeded, causing a drop from 96 ± 1% to 84 ± 4% ( P = 0.013). At moderate PHT, CO or DO 2 I did not improve significantly at any shunt‐flow. Conclusions In severe PHT, a shunt‐flow of 11% of CO represented the ideal shunt‐fraction. Augmentation of CO compensated for declined O 2 ‐saturation due to right‐to‐left shunting and improved DO 2 I. In moderate PHT, AS is less promising. © 2012 Wiley Periodicals, Inc.