Table 1. Summary of evidence by comparison investigated and study methodology.
| Comparator | RCTs [ref] | NRSIs [ref] | Ongoing trials |
| Choice of investigation | |||
| Flexible sigmoidoscopy vs. CTA | None | None | |
| Flexible sigmoidoscopy vs. other | None | None | |
| Colonoscopy vs. CTA | None | Nagata 2015 26 Yabutani 2014 21 | |
| Colonoscopy vs. other (e. g. standard care) | Green 2005 4 | Yamaguchi 2006 23 | |
| CTA vs. other | None | Ketwaroo 2012 18 Sun 2011 20 Jacovides 2015 25 | |
| Diagnostic mesenteric angiography vs. other | None | None | |
| Timing of first-line investigation | |||
| Colonoscopy: Early (< 24 hours) vs. late (> 24 hours) | Laine 2010 | Abeldawi 2014 24 Nagata 2016 27 Strate 2003 28 Rodriguez-Moranta 2007 19 | |
| Radiology: A) Urgent CTA vs. nonurgent B) Urgent mesenteric angiography vs. nonurgent | None None | None None | |
| Choice of treatment | |||
| Therapeutic endoscopy vs. mesenteric embolization | None | None | |
| Therapeutic endoscopy vs. other | None | Jensen 2000 30 | Matsuhashi JPRN-UMIN000008287 |
| Embolization vs. other | None | None | |
| Endoscopic agent A vs. B | None | Nakano 2015 22 Ishii 2011 17 | Barkun NCT02135627 |
RCT, randomized controlled trials; NRSI, nonrandomized studies of intervention; CTA, computed tomographic angiography.