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Article of the week: Remote ischaemic preconditioning reduces injury during partial nephrectomy

July 31, 2013/by admin Z.9

Every week the Editor-in-Chief selects the Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

Finally, the third post under the Article of the Week heading on the homepage will consist of additional material or media. This week we feature a video by Dr. Huang and colleagues to accompany their article.

If you only have time to read one article this week, it should be this one.

Effect of remote ischaemic preconditioning on renal protection in patients undergoing laparoscopic partial nephrectomy: a ‘blinded’ randomised controlled trial

Jiwei Huang, YongHui Chen, Baijun Dong, Wen Kong, Jin Zhang, Wei Xue, DongMing Liu and Yiran Huang

Department of Urology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China

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OBJECTIVE

• To evaluate whether remote ischaemic preconditioning (RIPC) reduces renal injury in patients undergoing laparoscopic partial nephrectomy (LPN).

PATIENTS AND METHODS

• In all, 82 patients undergoing LPN were randomly assigned to either the RIPC or control group, with 40 and 38 patients, respectively completing 6-months follow-up.

• RIPC was conducted after induction of anaesthesia, which consisted of three 5-min cycles of right lower limb ischaemia and 5 min of reperfusion during each cycle.

• The primary outcome was the absolute change in glomerular filtration rate (GFR) of the affected kidney by renal scintigraphy from baseline to 6 months.

• The secondary outcomes included urinary retinol-binding protein (RBP) levels measured at 24 and 48 h, serum creatinine, and estimated GFR (eGFR) at 1 and 6 months, and changes in GFR by renal scintigraphy.

RESULTS

• There were no differences in the change of GFR of the affected kidney at 6 months, while it was significantly decreased by 15.0% in the control group vs 8.8% in the RIPC group at 1 month (P = 0.034).

• The urinary RBP levels increased 8.4-fold at 24 h in the control group compared with a lower increase of 3.9-fold in the RIPC group (P < 0.001).

• There were no differences in the serum creatinine level or eGFR at 1 and 6 months between the two groups.

CONCLUSIONS

• In patients undergoing LPN, RIPC using transient lower limb ischaemia may reduce renal impairment in the short term, but failed in the longer term despite a non-significant trend in favour of RIPC.

• These novel data support the need for a larger study of RIPC during LPN surgery.

Read Previous Articles of the Week

Editorial: Accepting the positive results of unconventional methods

July 31, 2013/1 Comment/by Surena Matin

It is sometimes difficult to accept the results of a study based on a concept that is unfamiliar, involves unknown physiological mechanisms, or shows results that defy rational explanation. Remote ischaemic preconditioning (RIPC) is probably not a familiar topic to most urologists and, admittedly, was not familiar to this reviewer until now. Yet the authors, based on animal models and clinical data from non-urological literature, conducted a prospective, surgeon and patient ‘blinded’, randomised controlled trial to evaluate the potential benefit of RIPC in minimising ischaemic damage. By most available factors affecting postoperative renal function (warm ischaemia time, tumour complexity as measured by Preoperative Aspects and Dimensions Used for an Anatomical [PADUA] scores, preoperative renal function, tumour stage, etc.), no difference existed between the control and study groups. The authors found that patients undergoing RIPC had a lower change in estimated GFR (eGFR) at 1 month and appeared to have less ischaemic damage based on urinary marker levels (retinol binding protein) and functional imaging parameters. Unfortunately, the short-term benefit of RIPC did not translate to improvements over a longer period, with no differences at 6 months or in absolute eGFR between the two groups.

The authors should be congratulated for conducting such an elegant trial, unfamiliar and unconventional as the concept may be. Strengths of this study include its randomised ‘blinded’ design, correlation with metabolite, urinary marker and imaging findings, 6-month follow-up, and due diligence for assessing most pre-analytic factors. Limitations include the absence of data on residual functioning renal parenchyma, which arguably is the single best predictor of function in an operated kidney; additionally, this population with outstandingly good renal function (≈120 mL/min/1.73 m² in both groups) with very few comorbidities (<5–10% incidence of hypertension and diabetes) may not translate equally to the less healthy, more renally impaired Western population. The results may appear to be underwhelming, but I agree with the authors that further study is needed, and in particular for the Western population. The major impact from this reviewer’s perspective is for the patient with baseline renal compromise, whose risk for short- and long-term ischaemic renal injury is greater, and who could most benefit from a simple protective measure. Should we now enter unfamiliar territory and accept that the results of a randomised, ‘blinded’, prospective trial of a simple but unconventional method provide sufficient justification for testing this strategy in a higher risk population?

Surena F. Matin
Department of Urology, University of Texas MD Anderson Cancer Center, Houston, TX, USA

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Video: Remote ischaemic preconditioning: good for the short term

July 31, 2013/by admin Z.9