• Matt Wilkinson-Stokes, Jason Betson, and Simon Sawyer.
• Faculty of Medicine, Dentistry, and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia matt.wilkinson-stokes@outlook.com.
• Emerg Med J. 2023 Feb 1; 40 (2): 108113108-113.

BackgroundThe current guidelines of the American Heart Association (AHA) and European Society of Cardiology (ESC) recommend that when right ventricular myocardial infarction (RVMI) is present patients are not administered nitrates, due to the risk that decreasing preload in the setting of already compromised right ventricular ejection fraction may reduce cardiac output and precipitate hypotension. The cohort study (n=40) underlying this recommendation was recently challenged by new studies suitable for meta-analysis (cumulatively, n=1050), suggesting that this topic merits systematic review.MethodsThe protocol was registered on PROSPERO and published in Evidence Synthesis. Six databases were systematically searched in May 2022: PubMed, Embase, MEDLINE Complete, Cochrane CENTRAL Register, CINAHL and Google Scholar. Two investigators independently assessed for quality and bias and extracted data using Joanna Briggs Institute tools and methods. Risk ratios and 95% CIs were calculated, and meta-analysis performed using the random effects inverse variance method.ResultsFive studies (n=1113) were suitable. Outcomes included haemodynamics, GCS, syncope, arrest and death. Arrest and death did not occur in the RVMI group. Meta-analysis was possible for sublingual nitroglycerin 400 μg (2 studies, n=1050) and found no statistically significant difference in relative risk to combined inferior and RVMI at 1.31 (95% CI 0.81 to 2.12, p=0.27), with an absolute effect of 3 additional adverse events per 100 treatments. Results remained robust under sensitivity analysis.ConclusionsThis review suggests that the AHA and ESC contraindications are not supported by evidence. Key limitations include all studies having concomitant inferior and RVMI, not evaluating beneficial effects and very low certainty of evidence. As adverse events are transient and easily managed, nitrates are a reasonable treatment modality to consider during RVMI on current evidence.Prospero Registration NumberCRD42020172839.© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.

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