Left minilaparotomy and suprarenal aortic cross-clamping : a safe procedure on renal function

Objectives: “Fast-track” treatment has reduced both patient morbidity and mortality after major surgery. This technique is rarely used in aortic surgery, but in our institution it has been well standardized. This approach is based on stress-free surgical and anaesthetic techniques with optimization of pain control, early mobilization and resumption of oral nutrition. Surgical technique requires a left minilaparotomy to reduce surgical stress also in case of abdominal aortic aneurysm (AAA) requiring a suprarenal cross clamping. The aim of our paper is to evaluate the effects on renal function of suprarenal aortic cross clamping with left minilaparotomy for elective open surgical repair (OSR) of aortic diseases. Methods: data of all consecutive patients electively treated with left minilaparatomy requiring suprarenal cross clamping between 2009 and 2014 were retrospectively collected. On the basis on fast track protocol the outcomes were: recovery of bowel function, solid diet and ambulation; directly related to suprarenal cross clamping: early mortality, perioperative and short term renal function (analyzed following RIFLE - Risk, Injury, Failure, Loss of Function, End stage renal disease - criteria by considering for acute kidney insufficiency a serum creatinine increasing >50% for RISK and >2 times for INJURY respectively), intraoperative pH modifications and factors affecting postoperative outcomes were analyzed. Our standardized fast track protocol consists of a hospitalization the day before surgery; all patients were allowed to eat up to six hours before the operation and drink clear fluids up to 2 hours before the operation. One hour before anaesthesia, the patients received a single dose of antibiotic prophylaxis. Anaesthesia was performed with a blended technique : before intervention, patients received 1 mg of midazolam, 100 mg of fentanyl and 2.5 mg of droperidol; then, we placed an epidural catheter at T6-T7 with infusion of 18-20 ml of bupivacaine 0.5% to obtain a sensory block extended from dermatomeres T2 to S2. In addition to this block we administered a light general anaesthesia that consisted of induction with 1 mg/kg propofol and maintenance with alogenates and a laryngeal mask. The patient continued spontaneous breathing whenever possible with supported ventilation. No opioids were used during surgery. A transperitoneal aortic approach was used through a left subcostal incision with division of the rectus abdominis. A cutaneous incision of 10 to 15 cm, depending on the abdominal size, is made parallel to the condro-costal edge and spreads from the linea alba to the edge of the rectus muscle. In all patients, we used a cell saver and air heating for the maintenance of body temperature. No drains or nasogastric tubes were inserted at the end of the surgery. All patients awakened in the operating room. The laryngeal mask was removed, and the patients were transferred to the surgical ward. Postoperative analgesia was achieved with a continuous epidural infusion of 0.25% bupivacaine at a rate of 3–6 ml/h for 48 h supplemented by 1000 mg paracetamol orally administered every 8 h for additional analgesic demand. In the afternoon of day 0, if the patient’s general conditions were stable, they were encouraged to consume sugary drinks, and a semisolid diet was offered between two and six hours after surgery. Ten milligrams of metoclopramide was orally administered every 8 h. Soon after surgery, when the motor block was absent and the patients had stable hemodynamic parameters, they were forced to ambulate with assistance. Acute kidney injury was defined as a serum creatinine level was double or more the preoperative value according to RIFLE criteria . Results: Four-hundred-forty-five patients (408 men, 90.6%), mean age 70.8, underwent left minilaparotomic open surgical repair. Mean diameter of infrarenal AAA was 5.2±0.9 and ASA 3. In sixty-three cases (14%) a suprarenal cross clamping was required. In this group mean time of intervention was 180.1±65.7, infrarenal and suprarenal clamp time were 75 ± 33.1 and 28,3 ± 16.2 minutes respectively. Mean length of stay was 5.4±3.4. Atherosclerotic risk factors were common with literature (Tab.1). We had not perioperative death, but early term mortality was 6.3% (4 cases). Following our fast track protocol we had good results in suprarenal group in terms of passage of stool, solid diet and ambulation with high percentage of success quite similar to the patient did not require a suprarenal clamping (Fig.1). Intraoperative pCO2 and pH curve (Fig.2) did not show any variations during surgery. Variations of pO2 depended on the ventilation and awakening. These data seem to show how the short clamping time did not affect the metabolic activity without significant acidosis. Preoperative, immediate postoperative and at discharge serum creatinine mean value were 1.07±0.32, 1.31±0.36, 1.83±1.24 respectively. Based on RIFLE criteria for renal function we observed risk in 14.5% and injury in 3.2% at day 1, 12.9% and 9.6% at discharge respectively and 6.4% after 30 days for both criteria. No patient required haemodialysis (Tab.2). Conclusions: our data show good results following fast track protocol by performing a left mini laparotomy even requiring suprarenal aortic cross clamping, focusing clamping time, perioperative complications and early mortality. These data are comparable to literature, length of stay is shorter than in case of traditional laparotomy. Any alteration of long term renal function was not registered even though we observed a pick of creatinine at discharge which, however, improved after 30 days. On the base of RIFLE criteria we found a low percentage of risk or injury of renal function and we did not record any patient requiring hemodyalisis. So in our opinion minilaparotomy could be used also in case of suprarenal aortic cross clamping without significant risk of worsening of the renal function till end stage disease and life threatening complications.