Abstract
The first ischemic insult a tissue suffers is primary (1°). A second ischemic episode, such as thrombosis after free tissue transfer may be regarded as secondary (2°) ischemia. The current study investigated 2° ischemia in rodent epigastric flaps. Flaps were elevated in 50 Sprague‐Dawley rats: group 1 had 5 hours 1° venous ischemia induced by placement of microvascular clamps; group 2 was like group 1, except venous continuity was re‐established by venous anastomosis after resection of the venous segment previously microclamped; group 3 had 15 minutes of 1° ischemia, 24 hr later 5 hr of 2° venous ischemia was induced by placement of microvascular clamps; group 4 was like group 3, except the venous segment was excised. Necrosis was evaluated on postoperative day 7. Both secondary ischemic groups had significantly less flap survival than the corresponding primary ischemic groups (P<0.001 for both). Resection of a portion of the vein and subsequent microanastomosis did not reduce flap survival (NS). Secondary venous ischemia of 5‐hr duration is poorly tolerated by rodent skin flaps. There was no difference in flap survival in those flaps whose veins were clamped for 5 hr compared to those flaps whose clamped venous segments were resected and re‐anastomosed. © Wiley‐Liss, Inc.