Goal-directed Hemodynamic Management and Kidney Injury After Radical Nephrectomy or Nephroureterectomy

Radical nephrectomy and nephroureterectomy are common operations for the treatment of renal cell carcinoma and upper tract urothelial carcinoma, respectively. However, acute kidney injury frequently occurs after surgery. And the occurrence of acute kidney injury is associated with an increased risk of chronic kidney disease. Intraoperative hypotension is identified as an important risk factor of postoperative acute kidney injury. Preliminary studies showed that goal-directed hemodynamic management may reduce kidney injury after surgery but requires further demonstration. We hypothesized that goal-directed hemodynamic management combining hydration, inotropes, and forced diuresis to maintain pulse pressure variation \<9%, mean arterial pressure ≥85 mmHg, and urine flow rate \>200 ml/h (3 ml/kg/h) may reduce the incidence of acute kidney injury and improve long-term renal outcome after radical nephrectomy or nephroureterectomy. The purpose of this study is to investigate the effect of goal-directed hemodynamic management on the occurrence of acute and persistent kidney injury in patients following radical nephrectomy and nephroureterectomy.

Renal cancer accounts for 20.3% of urinary system tumors, and the incidence is still increasing. Surgical resection is the main treatment of renal cancer; radical nephrectomy is the standard operation for renal cancer of stage T2 or above. For upper tract urothelial carcinoma (UTUC) which includes renal pelvis cancer and ureteral cancer, radical nephroureterectomy is the gold standard treatment. Both procedures involve the removal of one kidney. Acute kidney injury (AKI) is a common complication after radical nephrectomy and nephroureterectomy, with reported incidence from 53.9% to 72.7%. AKI is associated with the development of chronic kidney disease (CKD) and is an independent risk factor of new onset CKD in patients without underlying kidney disease. A meta-analysis showed that, at one year after surgery, patients with AKI had a 2.7-fold increased risk of new onset or progression of CKD and a 4.8-fold increased risk of end-stage renal disease. Moreover, even mild AKI is associated with renal insufficiency at 1 to 2 years after surgery.

Taking active measures to reduce the incidence of AKI may improve long-term renal function after radical nephrectomy and nephroureterectomy. Many clinical studies show that intraoperative hypotension is an important risk factor of postoperative kidney injury. For example, a study found that intraoperative mean arterial pressure (MAP) \<65 mmHg or a decrease of more than 20% from baseline was associated with an increased risk of postoperative AKI; the risk of AKI increased alone with prolonged duration of hypotension. However, recent randomized controlled trials showed inconsistent results regarding the effect of tight blood pressure management strategy on kidney outcome. Relevant studies indicated that hydration with forced diuresis and inotropes to maintain cardiac output and blood pressure might improve renal outcome.

In a previous pilot trial of the authors, goal-directed hemodynamic management combining hydration and inotropics reduced the incidence of AKI by about 40% in patients following partial nephrectomy. However, the difference was not statistically significant due to insufficient sample size. The purpose of this trial is to investigate whether goal-directed intraoperative hemodynamic management combining hydration, inotropics, and forced diuresis can reduce the occurrence of acute and persistent kidney injury in patients undergoing radical nephrectomy and nephroureterectomy.

Eligibility Criteria:
Inclusion criteria:

1. Age of 18 years or older;
2. Scheduled to undergo unilateral radical nephrectomy for renal cancer or unilateral radical nephroureterectomy for upper tract urothelial carcinoma.

Exclusion criteria

1. Diagnosed with chronic kidney disease stage 4 or stage 5 (GFR\<30 ml/min/1.73m2) before surgery;
2. Uncontrolled severe hypertension (systolic blood pressure ≥180 mmHg or diastolic blood pressure ≥110 mmHg);
3. Combined with cardiovascular diseases with Revised Cardiac Risk Index (RCRI) \>1 or metabolic equivalents (METs) \<4;
4. Unable to communicate due to severe dementia, language barrier, or end-stage disease before surgery;
5. Other conditions that are considered unsuitable for inclusion (specific reasons should be indicated).