The second speaker was Dr. Uzzo, who focused on intraoperative renal protective techniques to preserve renal function. This was an excellent continuation of the discussion that Dr. Volpe provided regarding preoperative evaluation.
The principles of this talk are: More nephrons spared and less ischemia time is better; but, fewer nephrons spared and more ischemia time are not uniformly worse. There are NO DEFINITIVE intraoperative strategies proven to mitigate ischemic risk.
All case fall on the spectrum – on one hand, you have a healthy kidney with no ischemia time. On the other, you have an unhealthy kidney with long ischemia time. The key is to find a balance, or lean towards the former.
The new AUA guidelines do emphasize prioritizing NSS for pT1 tumors as it minimizes risk of CKD while maximizing oncologic outcomes (Grade B recommendation). He then provided some good numbers to remember:
1. Mean change in GFR with radical nephrectomy: 25-40 mL/min
* His own method is to assume about 30% loss of GFR with radical nephrectomy
2. Mean change in GFR with NSS: 2-10 mL/min
There are 4 main intra-operative strategies that he addressed today:
1. Warm and cold ischemia time
- AUA guidelines – physicians should aim to reduce warm ischemia time. The actual time threshold is not well defined, but thought to be about 25-30 minutes. In general, recovery from cold ischemia time ~60-90 minutes is well tolerated.
- Take-home point: Long warm ischemia time hurts. Short warm ischemia time is not as important as quantity and quality of preserved parenchyma. This is more important than ischemia time!
- Warm ischemia time is associated with 7.4% lower recovery than cold ischemia – so for patients where every GFR point counts, cold ischemia is probably worthwhile
- Recent Eur Urol prospective, randomized trial
- Only patients with GFR >45 were included – important to remember that!
- Primary outcome was GFR change at 6 months
- eGFR was not significantly different with or without 12.5 IV mannitol
- As such, it is no longer recommended
- However, Dr. Uzzo does still use it in patients with <45 GFR
3. Fluid/BP management
- Controlled hypotension – prospective study of 100 patients with zero ischemia time and controlled hypotension (MAP ~70) found reduced bleeding (primary outcome) and no Acute renal failure (ARF). GFR dropped slightly initially, but had recovered at 3 months.
- No level 1 evidence regarding fluid management strategies for partial nephrectomy
- His general strategy is to minimize prerenal etiology of ARF by maximizing preload and giving fluids
- However, ERAS data from bladder cancer literature would suggest limiting fluid volume
- Uncertain which is the right approach at this time
- There is a lot of literature in cardiovascular surgery suggesting benefit of statins perioperatively
- Dr. Uzzo’s group assessed statin use in 1056 patients undergoing NSS retrospectively
- Primary outcome was development of AKI within 7 days
- On MVA, statin use was NOT associated with higher or lower AKI rates
- From a purely GFR standpoint, there is no indication at this time for statin use – Dr. Finelli will discuss other reasons to consider it
Speaker: Robert Uzzo, Fox Chase Cancer Center, Philadelpha, USA
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