该试验的主要终点是在96小时内造影剂肾病进展情况。CIN在正常体温组的患者中发生率是18.6%，在低体温组患者中是22.4%（P=0.59; 如图所示）。

对血清肌酐的影响

与低体温组的58位患者相比，基线血清肌酐水平在70例体温正常患者中略高（1.97 mg/dL vs. 1.78 mg/dL; P=0.16）。在最初2天内，两组血清肌酐水平偶有升高：24小时,正常体温组1.91mg/dL vs. 低体温组1.77 mg/dL (P=0.30)；48小时，正常体温组2.21mg/dL vs. 低体温组1.94 mg/dL (P=0.09)。

Stone医生说，在第72小时和第96小时，血清肌酐水平在正常体温组达到2.11mg/dL的水平，低体温组为1.92mg/dL。两组差异不显著。

不良事件率

在30天时，两组均未发生如心房颤动和静脉并发症的不良事件。在其他不良事件，如全因死亡，急性心肌梗塞、透析、再住院以及出血方面两组也没有差别。“复合不良事件的总体发生率在两组之间几乎是一样的。”Stone医生说道(正常体温组为37.1% vs. 低体温组37.9%；P=0.93)

COOL RCN是一个前瞻性随机试验，目的是检查对于接受碘对比剂的患者应用低体温(33-34ºC)系统的情况。在2006年3月至2007年8月，Stone医生及其同事将136位患者随机分到低体温组或对照组。Stone医生说，该研究最初因为Radiant的财务问题没有解决而提前终止。但是，ZOLL Circulation 购买了Radiant的资产并且资助完成了本研究。

研究的局限性

Stone医生提到本研究存在几个局限之处。据观察对照组对比剂肾病率要低于预期的35%。计划入选的400名患者中仅有136人入选，导致了对低体温治疗效果的过高估计。

Antonio L. Bartorelli医生是意大利米兰大学心脏病学院Centro Cardiologico Monzino IRCCS的高级副教授，他说治疗组没有显示出低体温治疗的受益尽管它明显地降低了风险，水化治疗效果更好的趋势渐显。他说“鉴于在本试验当中与预期对比剂肾病发生率相比，实际应该期望的对比剂肾病发生率要更低，因此需要400名以上的患者加入试验来显示低体温的潜在益处。”

（医心网 孟祥飞 翻译 刘瑞琦 校对）

（www.tctmd.com）

COOL RCN: No Significant Reduction in Contrast Induced Nephropathy 

1.91 mg/dL in the normothermia group vs. 1.77 mg/dL in the hypothermia group at 24 hours (P=.30); and 2.21 mg/dL in the normothermia group vs. 1.94 mg/dL in the hypothermia group at 48 hours (P=.09).

Serum creatinine levels by 72 hours and 96 hours had reached 2.11 mg/dL in the normothermia group vs. 1.92 mg/dL in the hypothermia group. None of the differences between the groups were significant, Stone said.

Adverse event rate

There were no adverse events at 30 days in both groups for ventricular fibrillation and venous complications. There were no differences in other adverse events including all-cause mortality, acute MI, dialysis, rehospitalization, and bleeding. "The overall rate of composite adverse events was almost identical between the two groups," Stone said (37.1% in the normothermia group vs. 37.9% in the hypothermia group; P=.93).

COOL RCN was a prospective, randomized trial to determine the utility of systemic hypothermia (33-34ºC) in patients who received iodine contrast. Between March 2006 and August 2007, Stone and colleagues randomized 136 patients to hypothermia or control. The study was originally terminated early due to financial insolvency of Radiant, according to Stone. However, ZOLL Circulation purchased the Radiant assets and funded completion of the study.

Study limitations

Stone said there were several limitations to this study. The observed rate of radiocontrast nephropathy in the control arm was lower than the 35% rate they anticipated. Only 136 of the planned 400 patients were enrolled, which resulted in a wide point estimate for the treatment effect of systemic hypothermia.

Antonio L. Bartorelli, MD, senior associate professor at the Centro Cardiologico Monzino IRCCS, Institute of Cardiology, University of Milan in Italy, said the treatment group did not show any benefit from systemic hypothermia despite an apparent lower risk profile and a trend toward better hydration prophylaxis. "Given the lower radiocontrast nephropathy rate that should be expected as compared to that assumed in this trial, more than 400 patients would be likely required to demonstrate a potential benefit of hypothermia," he said.

Disclosures:

Dr. Stone reports no relevant conflicts of interest.
Dr. Bartorelli reports no relevant conflicts of interest.

（source：www.tctmd.com）