The first speaker was Dr. Volpe, who focused on pre-operative assessment and evaluation. He gave a very nice talk on important considerations from a pre-operative standpoint.
The important factors predicting kidney function preservation include:
- Tumor factors
- Patient factors
Baseline renal function
Patient characteristics - Surgical factors
The Surgical factors are often “modifiable”, but the tumor and patient characteristics are not.
- Baseline Kidney Function
- Baseline renal function is the strongest predictor of postoperative renal function
- Multiple studies have demonstrated its importance
- Brian Lane paper, J Urol 2011 – Comparing WIT and CIT in NSS
o Patient baseline renal function was strongest predictor of AKI and chronic renal function outcomes - Another paper by Brian Lane and colleagues very nicely demonstrated the difference between medical CKD and surgically induced CKD
o Patients with baseline medical CKD had higher chanced of 50% postoperative drop in GFR and OS
o Patients with surgically induced CKD had similar outcomes with patients with no CKD at baseline
1. Creatinine
- While primarily eliminated through glomerular filtration, about 10% is secreted actively
- As such, it is NOT a reliable measure of baseline renal function
- Highly variable with regards to age, sex, gender, body muscle mass, diet, medications
2. Glomerular filtration rate
- Very reliable measure of baseline renal function – normal is between 90-125 mL/min/1.73 m2
- Best index of measurement
- * sCr exceeds upper normal of reference values only when GFR is already below 50!
- GFR measurement is ideally measured with an agent that is completed filtered but is not secreted or reabsorbed – however, these tests are expensive.
- Calculated measurement of GFR is a cheaper, relatively accurate way of measuring GFR
- - Utilize sCr, age, gender and race to help calculate GFR
- - Traditionally, had been the Cockcroft-Gault equation (1976), then MDRD (1999)
- - Most recently, the CKD-EPI (2009) is thought to be the most accurate
- However, for patients older than 70, the BIS1 and BIS2 equations may be most accurate – BIS2 preferred
3. Urinalysis
- Pre-operative urinalysis has important value
- Can help identify hematuria (urologic or nephrologic), infection, sediment, and proteinuria
4. Proteinuria and albuminuria
- Normal values: Proteinuria < 150 mg/24 hrs, albumin <30 mg/24 hrs
- There are many etiologies for proteinuria, but they warrant evaluation for baseline CKD
- Albuminuria has become so important, that the recent 2012 consensus on CKD evaluation includes albuminuria as part of the classification, along with GFR
- Have been associated with survival outcomes
1. Contrast-enhanced CT or 3D CT scan
- While they are important for staging and diagnosis, they should be utilized for other purposes as well
- Important for identifying vascular anatomy, calcifications, atherosclerosis, urologic abnormalities
- They can also be used to approximate baseline renal function in recent studies by calculating parenchymal volume
- Mag3 vs. DTPA scans – DTPA preferred, but due to risk of renal injury in patients with CKD, often limited in terms of ability to administer
- Particularly important in patients with renal asymmetry, but may be useful in predicting postoperative GFR loss
- Can be valuable in patient counseling, and even in decision making – decision to pursue radical or partial nephrectomy
Speaker: Alessandro Volpe, Italy
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal