BMC Pulmonary Medicine (Feb 2021)

Pulmonary vasodilation by sildenafil in acute intermediate-high risk pulmonary embolism: a randomized explorative trial

  • Asger Andersen,
  • Farhad Waziri,
  • Jacob Gammelgaard Schultz,
  • Sarah Holmboe,
  • Søren Warberg Becker,
  • Tage Jensen,
  • Hanne Maare Søndergaard,
  • Karen Kaae Dodt,
  • Ole May,
  • Ulrik Markus Mortensen,
  • Won Yong Kim,
  • Søren Mellemkjær,
  • Jens Erik Nielsen-Kudsk

DOI
https://doi.org/10.1186/s12890-021-01440-7
Journal volume & issue
Vol. 21, no. 1
pp. 1 – 8

Abstract

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Abstract Background To investigate if acute pulmonary vasodilation by sildenafil improves right ventricular function in patients with acute intermediate-high risk pulmonary embolism (PE). Methods Single center, explorative trial. Patients with PE were randomized to a single oral dose of sildenafil 50 mg (n = 10) or placebo (n = 10) as add-on to conventional therapy. The time from hospital admission to study inclusion was 2.3 ± 0.7 days. Right ventricular function was evaluated immediately before and shortly after (0.5–1.5 h) randomization by right heart catheterization (RHC), trans-thoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). The primary efficacy endpoint was cardiac index measured by CMR. Results Patients had acute intermediate-high risk PE verified by computed tomography pulmonary angiography, systolic blood pressure of 135 ± 18 (mean ± SD) mmHg, increased right ventricular/left ventricular ratio 1.1 ± 0.09 and increased troponin T 167 ± 144 ng/L. Sildenafil treatment did not improve cardiac index compared to baseline (0.02 ± 0.36 l/min/m2, p = 0.89) and neither did placebo (0.00 ± 0.34 l/min/m2, p = 0.97). Sildenafil lowered mean arterial blood pressure (− 19 ± 10 mmHg, p < 0.001) which was not observed in the placebo group (0 ± 9 mmHg, p = 0.97). Conclusion A single oral dose of sildenafil 50 mg did not improve cardiac index but lowered systemic blood pressure in patients with acute intermediate-high risk PE. The time from PE to intervention, a small patient sample size and low pulmonary vascular resistance are limitations of this study that should be considered when interpreting the results. Trial Registration: The trial was retrospectively registered at www.clinicaltrials.gov (NCT04283240) February 2nd 2020, https://clinicaltrials.gov/ct2/show/NCT04283240?term=NCT04283240&draw=2&rank=1 .

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