EURURO-5520; No. of Pages 2 EUROPEAN UROLOGY XXX (2014) XXX–XXX

available at www.sciencedirect.com journal homepage: www.europeanurology.com

Platinum Priority – Editorial and Reply from Authors Referring to the article published on pp. x–y of this issue

To Clamp or Not To Clamp the Main Renal Artery: The Debate Continues Ithaar H. Derweesh a,*, Paul Russo b a

Department of Urology, University of California San Diego Health System, La Jolla, CA, USA;

b

Department of Surgery, Urology Service, Memorial

Sloan-Kettering Cancer Center, New York, NY, USA

In this month’s issue of European Urology, Desai et al. describe a feasibility study utilizing superselective clamping of arteries close to the tumor to achieve regional ischemia to improve robotic assisted partial nephrectomy (PN) and, presumably, to protect the non–tumor-bearing kidney [1]. The investigators also utilized monopolar electrocautery during the resection. The authors report incremental shortterm improvement in renal functional outcome (estimated glomerular filtration (eGFR) rate decrease in favor of superselective vs conventional main renal artery–clamped PN at last follow-up of 11% vs 17%, with similar estimated blood loss [EBL] rates [200 ml vs 150 ml] but higher transfusion rates [24% vs 6%] in superselective patients). PN, in general, and minimally invasive (robotic assisted) PN, specifically, is a complex operation requiring surgical expertise and with persistent concerns about perioperative bleeding and urinary complications. Despite the last decade of development, PN remains underutilized in the United States. At issue in this work is the question of whether this latest complex technical variation should be pursued by others or requires more study involving other experts to delineate its ultimate role in PN. One obvious question raised by this study relates to blood loss. Despite no significant difference in EBL—which may reflect imprecise operating room estimates, which we have all witnessed—the superselective technique’s transfusion rate of 24% is significantly higher than most published PN series. This finding could indicate that collateral blood flow, possibly from venous channels draining from unclamped areas of the kidney, is unchecked during the robotic procedure and possibly manifests itself following desufflation in the recovery room or on the ward. One wonders if the higher blood transfusion risk is worth the

small benefit in early eGFR that ultimately may not be clinically important, particularly since increasingly convincing data suggest that primary drivers for renal functional outcome following PN are nonmodifiable factors. Desai et al. claim that their technique provides adequate ischemic control of the tumor-bearing kidney, yet they still use monopolar electrocautery in their resection [1]. This begs the question, if superselective arterial clamping was adequate for providing a hemostatic field for resection, then why the additional energy requirement? The authors do not provide comparator groups with superselective clamping and pure cold resection or clampless and thermal resection to address this important point; however, the conclusion that may be drawn is inescapable, namely, the authors did not feel completely comfortable proceeding with cold resection in the face of a potentially nonhemostatic resection bed. What we are left with, actually, is augmented energy-based resection with superselective arterial clamping to provide extra reassurance. Conversely, the question that could be asked is, how differently would patients have fared if a completely clampless technique were utilized with or without energy-based resection? Comparative analyses of open cohorts utilizing clampless warm and cold ischemic technique demonstrate no significant difference in renal functional outcome (de novo stage III chronic kidney disease [CKD] or DeGFR) between these groups at the 1-yr mark or later, provided that cold ischemic protection or limited warm ischemic time is utilized [2–4]. Increasingly compelling data demonstrate that the primary determinants for renal functional outcome after PN are predominantly nonmodifiable patient factors (eg, baseline eGFR, body mass index [BMI], and Charlson

DOI of original article: http://dx.doi.org/10.1016/j.eururo.2014.01.017. * Corresponding author. Department of Urology, Moores UCSD Cancer Center, 3855 Health Sciences Drive, Mail Code: 0987, La Jolla, CA 92093-0987, USA. Tel. +1 858 822 6187; Fax: +1 858 822 6188. E-mail address: [email protected] (I.H. Derweesh). 0302-2838/$ – see back matter # 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.eururo.2014.02.001

Please cite this article in press as: Derweesh IH, Russo P. To Clamp or Not To Clamp the Main Renal Artery: The Debate Continues. Eur Urol (2014), http://dx.doi.org/10.1016/j.eururo.2014.02.001

EURURO-5520; No. of Pages 2 2

EUROPEAN UROLOGY XXX (2014) XXX–XXX

score) that influence the ‘‘quality’’ of nephrons spared [3,4]. Another important determinant is volume or percentage (ie, quantity) of parenchyma spared [4]. Even in the setting of a solitary kidney, as demonstrated by Lane et al. in a multicenter comparison of cold and warm ischemia, percentage of parenchymal preservation at time of PN is the most important predictor of ultimate renal function [5]. This does not discount the role of ischemia. Even though preexisting patient medical factors and the amount of parenchymal preservation are the major components of ultimate renal function [2–6], prolonged ischemic time does play a role in the quality of preserved nephrons. Thompson et al. analyzed 362 patients with solitary kidney who underwent PN with warm ischemia and found that, in addition to percentage of kidney preserved ( p < 0.001) and preoperative glomerular filtration rate (GFR; p < 0.001), prolonged warm ischemia time (>25 min; hazard ratio: 2.27; p = 0.049) was a factor that correlated with de novo stage IV CKD [6]. Kopp et al. studied patients with two kidneys who underwent 64 clampless and 164 clamped open PNs and demonstrated association of increasing RENAL score (odds ratio [OR]: 1.71; p = 0.002) and BMI (OR: 1.1; p = 0.042) with development of de novo stage III CKD [3]. Yossepowitch et al. separately analyzed 70 patients with solitary kidney and 592 patients with two kidneys who underwent cold ischemia and noted in multivariate analyses of each group that cold ischemia duration and intraoperative blood loss were independently associated with early GFR changes, but by 12 mo after PN, age was the only independent factor significantly associated with GFR decrease [2]. Consequently, the effect of a modifiable factor such as ischemia time appears somewhat limited over the long run, especially if kept under 20–25 min warm [3,6,7] and 35 min cold, with cold ischemic protection extending time of acceptable ischemia to 2 h [7]. Indeed, with a 50% reduction of warm ischemia times to well below 20 min using the ‘‘early unclamping’’ technique [8], which has been adopted by several centers of excellence, the question then becomes how much more ischemia time do we need to reduce in central masses at higher risk for hemorrhage by using the far more complex superselective clamping method described by Desai et al. [1]? Another important consideration is the potential adverse outcome that blood transfusion is associated with in the setting of renal cell carcinoma (RCC). Emerging data suggest that transfusion is associated with 3.5-fold hazard of allcause mortality in cT2 renal masses [9], and transfusion at the time of cytoreductive nephrectomy is associated with a 2-fold increased risk of cancer-specific mortality within 12 mo [10]. Although the authors’ cohort did not have patients with metastatic disease, the superselective clamping group nonetheless contained significant proportions of T1b and higher (>30%) and high-grade tumors (>26%), which represent a higher-risk cohort at potential oncologic risk from blood transfusion. Although a potential link

between blood transfusion and oncologic outcomes in RCC deserves further investigation, this alone should give pause to widespread adoption of this superselective clamping technique, with its high transfusion requirement. In the end, does extending the already expert requirements for performing a safe and effective PN (by any technique) to include superselective clamping provide sufficient renal functional dividend to justify the augmented technical demands or worries regarding blood transfusion? In conclusion, although Desai et al. demonstrate feasibility of superselective clamping, the short-term renal functional benefits are only incremental, and the risks associated with increased requirements for blood transfusion cannot be discounted. This technique is not, in our opinion, ‘‘ready for prime time’’ and utilization should be limited to situations in which avoidance of the clamping of the main renal artery is required to minimize ischemic injury to the non–tumor-bearing kidney to maximally protect the more susceptible kidney. Under those restricted conditions, the added transfusion requirement that this technique entails may be worth it. Conflicts of interest: The authors have nothing to disclose.

References [1] Desai MM, de Castro Abreu AL, Leslie S, et al. Robotic partial nephrectomy with superselective versus main artery clamping: a retrospective comparison. Eur Urol. In press. [2] Yossepowitch O, Eggener SE, Serio A, et al. Temporary renal ischemia during nephron sparing surgery is associated with short-term but not long-term impairment in renal function. J Urol 2006;176: 1339–43. [3] Kopp RP, Mehrazin R, Palazzi K, et al. Factors affecting renal function after open partial nephrectomy-a comparison of clampless and clamped warm ischemic technique. Urology 2012;80:865–70. [4] Simmons MN, Hillyer SP, Lee BH, et al. Functional recovery after partial nephrectomy: effects of volume loss and ischemic injury. J Urol 2012;187:1667–73. [5] Lane BR, Russo P, Uzzo RG, et al. Comparison of cold and warm ischemia during partial nephrectomy in 660 solitary kidneys reveals predominant role of nonmodifiable factors in determining ultimate renal function. J Urol 2011;185:421–7. [6] Thompson RH, Lane BR, Lohse CM, et al. Renal function after partial nephrectomy: effect of warm ischemia relative to quantity and quality of preserved kidney. Urology 2012;79:356–60. [7] Becker F, Van Poppel H, Hakenberg OW, et al. Assessing the impact of ischaemia time during partial nephrectomy. Eur Urol 2009;56: 625–35. [8] Nguyen MM, Gill IS. Halving ischemia time during laparoscopic partial nephrectomy. J Urol 2008;179:627–32. [9] Kopp RP, Mehrazin R, Palazzi KL, et al. Survival outcomes after radical and partial nephrectomy for clinical T2 renal tumors categorized by RENAL nephrometry score. BJU Int. In press. [10] Margulis V, Shariat SF, Rapoport Y, et al. Development of accurate models for individualized prediction of survival after cytoreductive nephrectomy for metastatic renal cell carcinoma. Eur Urol 2013;63: 947–52.

Please cite this article in press as: Derweesh IH, Russo P. To Clamp or Not To Clamp the Main Renal Artery: The Debate Continues. Eur Urol (2014), http://dx.doi.org/10.1016/j.eururo.2014.02.001

To clamp or not to clamp the main renal artery: the debate continues.

To clamp or not to clamp the main renal artery: the debate continues. - PDF Download Free
143KB Sizes 2 Downloads 1 Views