What is the optimum prophylaxis against gastrointestinal haemorrhage for patients undergoing adult cardiac surgery: histamine receptor antagonists, or proton-pump inhibitors?

A best evidence topic was written according to a structured protocol. The question addressed was what is the optimum prophylaxis against gastrointestinal haemorrhage for patients undergoing adult cardiac surgery: histamine receptor antagonists (H(2)RA) or proton-pump inhibitors? A total of 201 papers were found; of which, 8 represented the best evidence. The authors, date, journal, study type, population, main outcome measures and results were tabulated. Only one randomized controlled trial (RCT) with relevant clinical outcomes was identified. The rest of the studies consisted of five prospective studies and two retrospective studies. In the RCT, there were no reported cases of gastrointestinal haemorrhage in the proton-pump inhibitor cohort, whereas 4 patients taking H(2)RA developed it. The rate of active gastrointestinal ulceration was higher in the H(2)RA cohort in comparison with the proton-pump inhibitor cohort (21.4 vs 4.3%). A prospective study followed 2285 consecutive patients undergoing cardiac surgery who received either no prophylaxis, or a proton-pump inhibitor. Chi-squared analysis showed the risk of bleeding to be lower in those receiving the proton-pump inhibitor (P < 0.05). Another study of 6316 patients undergoing coronary artery bypass grafting demonstrated a reduced risk of gastrointestinal bleed with prophylactic intravenous omeprazole (odds ratio = 0.2; confidence intervals = 0.1-0.8; P < 0.05). One study successfully showed that proton-pump inhibitors are effective in adequately suppressing gastric acid levels, regardless of Helicobacter pylori infection status; conversely, this study suggested that H2RAs were not. The evidence for H2RAs is marginal, with no study showing a clear benefit. One study showed that ulcer prophylaxis with H(2)RA did not correlate with the clinical outcome. Another study demonstrated gastric ulceration to be a common gastrointestinal complication in spite of regular H(2)RA use. There is also evidence to suggest that acid suppression increases the risk of nosocomial pneumonia, although open heart surgery may be a confounding factor in this association. Two RCTs showed that H2RAs may augment the immune system and reducing stress following cardiac surgery. Proton-pump inhibitors appear to be the superior agent for prophylaxis against gastrointestinal bleed in patients undergoing cardiac surgery, although rigorous comparative data are sparse. Furthermore, level-I evidence would confirm this.