The role of intravenous hydration at the time of primary percutaneous intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) remains unclear. Guidelines are vague, supported by low level evidence, and hydration is used less often than other clinical settings.To perform a systematic review and meta-analysis of all randomized controlled trials assessing intravenous hydration compared with non-hydration for prevention of contrast induced nephropathy (CIN) and In-hospital mortality in patients with STEMI undergoing primary PCI.

Medline, EMBASE and the Cochrane Register were searched to September 2018. Included studies reported the incidence of CIN, In-hospital mortality, requirement for dialysis and heart failure. Relative risks with 95% confidence intervals (CIs) for individual trials were pooled using a random effects model.

Three moderate quality trials were identified including 1074 patients. Overall, compared with no hydration, intravenous hydration significantly reduced the incidence of CIN by 42% (RR 0.58; 95% CI: 0.45 to 0.74, p < 0.001). The estimated effects upon all-cause mortality (RR 0.56; 95% CI: 0.30 to 1.02, p = 0.057) and the requirement for dialysis (RR 0.52, 95% CI 0.14–1.88, p = 0.462) were not statistically significant. The outcome of heart failure was not consistently reported.

Intravenous hydration likely reduces the incidence of CIN in patients with STEMI undergoing primary PCI. However, for key clinical outcomes such as mortality, heart failure and dialysis the effect estimates were imprecise. Further high quality studies are needed to clarify the appropriate volume of fluid and effects on outcomes.