Pulmonary Artery Wedge Pressure Respiratory Variation Increases With Sodium Nitroprusside Vasodilator Challenge

Steven P. Maurides, Devin Blankinship, Kavin Panneerselvam, Gregory R. Jackson, Stefano Ghio, Ryan J. Tedford, Brian A. Houston

Research output: Contribution to journalArticlepeer-review


Background: The physiologic factors leading to pulmonary arterial wedge pressure respiratory variation (PAWPvar) are underexplored. We hypothesized that PAWPvar is associated with baseline PAWP and would predict response to sodium nitroprusside (SNP). Methods and Results: We performed a retrospective study of right heart catheterization studies in 51 subjects with SNP challenge at our institution from 2012 to 2019. PAWPvar was defined as expiratory minus inspiratory PAWP. Baseline %PAWPvar was inversely correlated with baseline PAWP (R = –0.5). SNP administration led to increased %PAWPvar (+27%, P <.01). Subjects with low baseline PAWPvar (less than the median) had an increase in PAWPvar with SNP (3 ± 4 mm Hg), whereas those with a high baseline PAWPvar (greater than the median) did not (–0.6 ± 4 mm Hg, P =.003). Those who had a greater than the median PAWPvar increase with SNP had greater cardiac output augmentation compared with those who had less than a median increase in PAWPvar (1.7 ± 1.5 L/min vs 0.9 ± 0.7 L/min, P =.02). An increasing PAWPvar after SNP was associated with significant discrepancy in the number of subjects achieving transplant-acceptable pulmonary vascular resistance (<2.5 Wood units) when calculated by expiratory versus mean PAWP (37 vs 27 subjects, 20% discrepancy rate). Subjects with a higher PAWPvar after SNP were more likely to demonstrate discrepant transplant-acceptable pulmonary vascular resistance calculations comparing expiratory versus mean PAWP than those with lower PAWPvar post-SNP (47% vs 13%, odds ratio 5.5, P =.03). Conclusions: Our findings indicate that PAWPvar is a meaningful physiologic parameter that is influenced by the compliance of the left heart/pulmonary vascular system and its relative preload and afterload states.

Original languageEnglish
Pages (from-to)1096-1099
Number of pages4
JournalJournal of Cardiac Failure
Issue number12
Publication statusPublished - Dec 2020


  • Hemodynamics
  • pulmonary artery wedge pressure
  • respiratory variation
  • vasodilator challenge

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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