Laparoscopic Aortorenal Bypass

Physiologically significant renal artery stenosis, mostly due to atherosclerosis, has been known to cause hypertension and deterioration of renal function (1-3). Percutaneous transluminal balloon angioplasty and intravascular stenting have evolved as the first-line therapy in recent years; however, they have provided inferior long-term patency (4).

Surgical revascularization remains the gold-standard definitive treatment of renal artery stenosis as well as the salvage treatment of failed endovascular intervention. However, the conventional open revascularization surgery is typically associated with significant patient morbidity and recovery. Laparoscopy was thought to have the potential to reduce the postrevascularization patient morbidity.

Hsu et al. from the Cleveland Clinic investigated the feasibility and the physiologic and pathologic outcomes of laparoscopic aortorenal bypass in the laboratory setting (5,6). Their reports also represented the first attempt to study laparoscopic ren-ovascular surgery in the surgical community.

In the initial report on laparoscopic renovascular surgery, the authors performed an aorta-to-left renal artery bypass using an interposition polyethylene graft in five large farm pigs, following extensive experience with laparoscopic vascular suturing from arduous practice in the in vitro setting as well as in approximately 20 animals (5). In the procedure, five to six trocars were used for transperitoneal access, and intracorporeal free-hand suturing and knot-tying techniques were used exclusively for vascular reconstruction. In this feasiblity study, the mean surgical time was 5.4 hours, and the mean renal ischemia time was 61 minutes. The mean end-to-side graft-to-aorta and end-to-end graft-to-renal artery anastomosis times were 34 and 40 minutes, respectively. The average estimated blood loss was 66 mL. Upon revascularization, there was prompt reperfusion of the kidney and Doppler-confirmed pulsation of the renal artery. On autopsy following the surgical procedure, there was anastomotic patency was present in all five cases.

Following the successful feasiblity study above, the same authors proceeded to investigate the long-term clinical and pathologic outcomes of laparoscopic aortorenal bypass in a survival animal study, in which a total of eight large farm pigs underwent the laparoscopic procedure (6). Again, the aorta-to-left renal artery bypass without graft was performed, involving transection of left renal artery and end-to-side aorta-to-renal artery anastomosis. Again, all steps were performed using totally intracorporeal laparoscopic surgical techniques. Furthermore, a novel method of in situ renal hypothermia was used to achieve intracorporeal renoprotective effects by infusion of ice-cold saline into the renal artery through a balloon catheter. In the study, all eight animals underwent the bypass procedure successfully. The median surgical time and total anastomotic time were 110 and 40 minutes, respectively. The median renal warm ischemic time was nine minutes. The median estimated blood loss was 30 mL. Postoperatively, one animal died of pneumonia, and the remaining seven experienced no postoperative complication and were euthanized at different time points from day 0 to week 6. Physiologically, there was no significant difference between preoperative and postoperative (at euthanasia) serum creatinine values (1.15 mg/dL vs. 1.2 mg/dL; p = 0.39). Peripheral renin activity was found to have a transient rise in the immediate postoperative period but normalize by one week postoperatively. On autopsy, a grossly normal left kidney with Doppler confirmation of blood flow in the repaired renal artery was identified in all seven animals. Radiographically, ex vivo angiography confirmed a patent anastomosis in all cases. Histologically, there was gradual resolution of mild acute tubular necrosis in the left kidney within six weeks, and there was gradual endothelialization of the aorto-left renal artery anastomotic site, which was found to be complete by six weeks. In short, durable success with physiologic, radiographic, and pathologic confirmation can be achieved in laparoscopic aortorenal bypass.

Subsequent to these two reports of successful laparoscopic aortorenal bypass, the Cleveland Clinic investigators studied another variation of laparoscopic surgical management of renal artery stenosis—laparoscopic splenorenal bypass (7). In the survival animal study, six dogs underwent the transperitoneal laparoscopic splenorenal bypass successfully, in which end-to-end splenic artery-to-left renal artery anastomosis was performed intracorporeally. Mean total operative time and renal ischemia time were 297 and 71 minutes, respectively. Five of six animals were kept alive from one to two months, and patent anastomoses were found in all animals on autopsy. This chronic canine study further supports that laparoscopic vascular bypass involving the renal artery can provide durable results in the laboratory setting.

Meraney et al. from the Cleveland Clinic investigated the feasibility and outcome of laparoscopic renal autotransplantation in the laboratory setting. This study represents the initial and only report of a completely laparoscopically performed renal autotransplantation.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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