Background:Current risk assessment approaches fail to identify the majority of patients at risk of sudden cardiac arrest (SCA). Noninvasive imaging of the cardiac sympathetic nervous system using single-photon emission computed tomography and positron emission tomography offers the potential for refining SCA risk assessment. While various [¹¹C]meta-hydroxyephedrine quantification parameters have been proposed, it is currently unknown whether regional denervation or global innervation yields greater SCA risk discrimination. The aim of the study was to determine whether the global innervation parameters yield any independent and additive prognostic value over the regional denervation alone.Methods:In a post hoc competing-risks analysis of the PAREPET trial (Prediction of Arrhythmic Events With Positron Emission Tomography), we compared global innervation and regional denervation parameters using the norepinephrine analog [¹¹C]meta-hydroxyephedrine for SCA risk discrimination. Patients with ischemic cardiomyopathy (n=174) eligible for an implantable cardioverter-defibrillator for the primary prevention of SCA were recruited into the trial. [¹¹C]meta-hydroxyephedrine uptake and clearance rates were measured to assess global (left ventricle mean) retention index and volume of distribution. Regional defects were quantified as the percentage of the left ventricle having values <75% of the maximum.Results:During a median follow-up of 4.2 years, there were 56 cardiac-related deaths, of which 26 were SCAs. For any given regional denervation volume, there was substantial heterogeneity in global innervation scores. Global retention index and distribution volume did not decrease until regional defects exceeded 40% left ventricle. Global scale parameters, retention index, and distribution volume (area under the curve=0.61, P=0.034, P=0.046, respectively), yielded inferior SCA risk discrimination compared to regional heterogeneity (area under the curve=0.74).Conclusions:Regional denervation volume has superior cause-specific mortality prediction for SCA versus global parameters of sympathetic innervation. These results have widespread implications for future cardiac sympathetic imaging, which will greatly simplify innervation analysis.Registration:URL: https://www.clinicaltrials.gov; Unique identifier: NCT01400334.

中文翻译：

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正电子发射断层扫描对局部与整体心肌交感神经活动进行成像，以改善缺血性心肌病患者的风险分层


背景：当前的风险评估方法无法识别大多数有心脏骤停（SCA）风险的患者。使用单光子发射计算机断层扫描和正电子发射断层扫描对心脏交感神经系统进行无创成像，为完善 SCA 风险评估提供了潜力。虽然已经提出了各种[ ¹¹ C]间羟基麻黄碱定量参数，但目前尚不清楚区域去神经支配或整体神经支配是否会产生更大的 SCA 风险区分。本研究的目的是确定全局神经支配参数是否比单独的区域去神经支配产生任何独立和附加的预后价值。方法：在 PAREPET 试验的事后竞争风险分析中（使用正电子发射断层扫描预测心律失常事件） ，我们使用去甲肾上腺素类似物 [ ¹¹ C]间羟基麻黄碱比较了整体神经支配和区域去神经支配参数，以进行 SCA 风险区分。该试验招募了符合植入式心律转复除颤器用于 SCA 一级预防的缺血性心肌病患者 (n=174)。测量[ ¹¹ C]间羟基麻黄碱的摄取和清除率，以评估整体（左心室平均值）保留指数和分布容积。区域缺陷被量化为左心室的百分比，其值为最大值的 <75%。 结果：在中位随访 4.2 年期间，有 56 例与心脏相关的死亡，其中 26 例为 SCA。对于任何给定的区域去神经支配量，全局神经支配评分存在很大的异质性。直到区域缺损超过左心室40%时，整体保留指数和分布容积才下降。 与区域异质性（曲线下面积 = 0.74）相比，全局尺度参数、保留指数和分布体积（曲线下面积 = 0.61， P = 0.034， P = 0.046）产生的 SCA 风险辨别力较差。结论：区域与交感神经支配的全局参数相比，去神经体积对 SCA 的特定原因死亡率预测具有更好的效果。这些结果对未来的心脏交感神经成像具有广泛的影响，这将大大简化神经支配分析。注册：URL：https://www.clinicaltrials.gov；唯一标识符：NCT01400334。