Heterotopic Heart Transplantation in Rats: Improved Anesthetic and Surgical Technique

Objective. An updated anesthetic and surgical technique in a rat model of heterotopic heart transplantation is described. Materials and Methods. A microsurgical technique via a suprarenal approach was performed, and is described in stepwise fashion, and several technical improvements are compared with previous descriptions. Lewis rats were used as donors and recipients (syngeneic model). Results. Factors that affected early surgical outcome included type of anesthetic used; surgeon skill, experience in handling blood vessels, and knowledge of small-animal anatomy; gentle manipulation during the operation; and duration of surgery (<1 hour). Use of isoflurane inhalation anesthesia (10 rats) vs intraperitoneal injection of ketamine, 75 mg/kg, and dexmedetomidine, 0.25 mg/kg (20 rats), was associated with improved early survival (90%) and no occurrence of paralysis, paraparesis, bleeding, or intestinal ischemia. Long-term survival (>11 months) with a functioning graft was achieved in all 9 surviving animals. Conclusions. Survival was substantially improved with administration of isoflurane anesthesia; surgeon microvascular surgical skills and knowledge of small-animal anatomy, and duration of surgery less than 1 hour. These factors collectively contributed to successful early outcomes after heterotopic heart transplantation in rats, with 90% freedom from morbidity and mortality, and resulted in long-term survival (>11 months) with a functioning graft in a syngeneic model. This heterotopic model in rats is suitable for short- and long-term studies of heart transplantation.