A Comparison of Renal Perfusion in Thoracoabdominal Aortic Aneurysm (TAAA) Repair
Condition: Renal Failure
MeSH terms: Renal Insufficiency; Aneurysm; Aortic Aneurysm; Aortic Aneurysm, Thoracoabdominal; Aortic Aneurysm, Thoracic
Study type: Interventional

Summary: 
      The purpose of this randomized trial was to determine whether renal perfusion with cold blood
      provides better protection against renal ischemia than perfusion with cold crystalloid in
      patients undergoing TAAA repair with left heart bypass.
    

Detailed description: 
      Despite improvements in surgical techniques and postoperative care, renal dysfunction has
      consistently remained a significant and potentially lethal complication after
      thoracoabdominal aortic aneurysm (TAAA) repair. In an attempt to alleviate postoperative
      renal failure and its associated mortality, several techniques and intraoperative strategies
      have been used including: intraoperative administration of diuretics, steroids, or
      prostaglandins; minimization of ischemic times; renal hypothermia with cold crystallid
      solutions; selective warm (normothermic) blood perfusion as part of a left heart bypass (LHB)
      system; and hemodilution. However, despite the use of adjuvant techniques, the incidence of
      renal failure after TAAA repair still ranges from 3% to 27%. One of the techniques mentioned
      above involves cold crystalloid renal artery perfusion. This method aims to reduce metabolic
      needs of the renal system by inducing local hypothermia. Because oxygen consumption decreases
      7% for each degree Celsius that temperature is reduced, the metabolic needs of tubular cells
      are reduced by almost 50% at 30 degrees Celsius. After the aorta is clamped and opened, the
      renal arteries are perfused with lactated Ringers solution (LR) that has been cooled to 4
      degrees Celsius utilizing a roller pump to transport the LR through an appropriately cooled
      ice bath. This decreases the temperature of the kidneys to an average of 20 degrees Celsius.
      The volume of LR required to achieve this temperature ranges from 600 to 1800 ml. Renal
      cooling has been shown to preserve renal tissue as long as warm ischemic time is kept to a
      minimum. We recently compared renal artery cold crystalloid perfusion with normothermic blood
      perfusion in a randomized clinical trial involving 30 patients and discovered via
      multivariable analysis that cold LR was protective against acute postoperative renal
      dysfunction. In this study, we found that 62.5% of patients receiving normothermic blood
      perfusion developed acute postoperative renal dysfunction versus 21.4% in the cold LR group
      (p = 0.03). One method of renal protection not often used involves selective cold blood
      perfusion of the renal arteries. This technique also aims to reduce renal ischemic time
      during aortic cross-clamping and improve oxygenation to renal tissues; thereby, preventing
      reperfusion injury and organ dysfunction often associated with this operation. During
      aneurysm repair, left atrio-distal aortic bypass is performed using a centrifugal pump.
      Tubing connected to the distal end of this circuit passes through a container of ice allowing
      the perfusion of both renal arteries with cold blood. The flow rates into the renal arteries
      range from 100 to 450 ml/min. The celiac axis and superior mesenteric artery remain
      individually perfused in the standard fashion using normothermic blood. The best method of
      achieving renal protection remains unclear. Currently, normothermic blood and cold LR remain
      the two most commonly used methods of renal artery perfusion during TAAA repair. This
      randomized trial compared the effectiveness of two forms of renal artery perfusion, cold LR
      versus cold blood, to identify which method is more beneficial in the prevention of
      postoperative renal dysfunction.
    

Intervention name(s): Cold blood renal perfusion; Cold crystalloid renal perfusion
Intervention type(s): Procedure; Procedure
Intervention description(s): Both kidneys receive intermitent perfusion with cold (4 degrees C) autologous blood during thoracoabdominal aortic aneurysm repair.; Both kidneys receive intermittent perfusion with cold (4 degrees C) lactated Ringer's solution during thoracoabdominal aortic aneurysm repair. This is the standard renal perfusion technique in our practice.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: renal failure; thoracoabdominal aortic aneurysm repair; cold crystalloid; cold blood; renal perfusion