Study	Reason for exclusion
Gale 1985	Randomised by flipping a coin Not intention‐to‐treat About 300 patients randomised to either vein patch or primary closure: 194 patients had the operation to which they were randomised, the remaining patients were randomised to 1 procedure but actually had the other procedure for some reason Results only available for the 194 patients who remained in the group to which they were originally allocated
Hertzer 1987	Non‐random comparison of patching performed by one surgeon and primary closure performed by other surgeons in the same institute (personal communication with Dr Hertzer)