Animal model for assessing collateral vein sealing with energy-based devices in revascularization surgery

Abstract

Introduction: energy sealing devices achieve hemostasis of the vessels through the heat generated and coagulation of the vascular wall's proteins. However, mid-term efficacy for venous graft sealing in arterial bypass surgery, remains unknown Objectives: to create an animal model which allows the comparison of mid-term efficacy and safety at the sealing zone after the healing process. To compare and assess which in vivo arterial models show lower morbidity and higher survival after 4 weeks postoperative. Material and methods: an in vivo experimental study of 16 New Zealand rabbits. In each rabbit a human saphenous vein (SV) with at least one venous collateral was implanted. Two arterial models were developed: infrarrenal aorta bypass with SV (n = 5) and aortoplasty with SV patch (n = 11). In both models the collateral was randomized ad sealed with one energy sealing devices: Electrothermal Bipolar Vessel Sealing (EBVS) or Harmonic scalpel (HS). Every animal was treated with antithrombotic prophylaxis and immunosuppressive medication. Intraoperative mortality, paraplegia, infection, bleeding, and survival was analyzed. Results: two animals (50 %) survive at the 7th postoperative day in the bypass model, but anyone survived the four weeks postoperative in this model. In the aortoplasty group, seven-day survival was 55,56 % (5/9) and 4-weeks survival was 44,44 % (4/9) (p = 0.05). Paraplegia rate was 100 % for the bypass model and much lower for the patch group (25 %) (p = 0,03). Mean ischemic time was lower for the aortoplasty model (37,11 ± 8,1 min) compared to bypass group (42 ± 10,61 min) (p = 0.414). No animal presented intrabdominal hemorrhage or adverse drug reaction for immunosuppressive medication. Conclusion: aortoplasty with SV patch model has shown a lower paraplegia rate and a lower mortality at 7 days in the animal model performed. Both bypass model and patch model have shown efficacy at the sealing zone but only in the aortoplasty model four animals survived after 4 weeks.

“In Vitro” Evaluation of Energy‐Based Sealing of Graft Side Branches in Bypass Surgery

“…Efficacy of energy‐based sealing systems has been studied in in vitro models [11, 13], as well as in animals [2, 4, 7] and humans [9, 14]. Indeed, EB and HS devices have proven to be a safe alternative to conventional ligature, in different surgical procedures such as pulmonary resection [3, 6, 9], laparoscopic colectomy [10], nephrectomy [15] hysterectomy [8, 16, 17], and thyroidectomy [18].…”

“…Sample size was estimated based on the results of a pilot study comparing burst pressure of ligature of collaterals (1171.6 ± 466.8 mmHg ( n = 5) and HE or EB ( n = 20) (581.4 ± 315 mmHg) [11]. Accepting an alpha risk of 0.05 and a beta risk of 0.2 in a two‐sided test, 10 subjects would be necessary in each group to recognize as statistically significant a minimum difference of 590 mmHg between any pair of groups.…”