A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'does preoperative ischaemic conditioning with gastric vessel ligation prior to oesophagectomy reduce anastomotic leaks? Altogether more than 70 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Five papers represent level III evidence while the remainder two are considered level IV. None of the seven papers reports statistically significant P-values, although one non-randomized controlled cohort study approaches statistical significance at P = 0.07. Three of the level III papers suggest that preoperative ischaemic conditioning prior to oesophagectomy may be associated with a lower anastomotic leak severity; being managed endoscopically rather than with a surgical intervention, however, again, none reached statistical significance. Preoperative ischaemic conditioning prior to oesophagectomy may not be associated with an increase in blood loss or length of time at definitive operation, reported by one of the seven studies. One paper reports that the timing of preoperative ischaemic conditioning may be associated with a better anastomotic leak profile if carried out 2 weeks previously as opposed to 5 days ahead of definitive surgery, although not statistically significant. The most consistent method in the literature reported ligation or division of the left gastric artery reported in six of the seven papers. We, therefore, cannot conclude that preoperative ischaemic conditioning with gastric vessel ligation prior to oesophagectomy is associated with reduced anastomotic leaks.