Reduced uptake of ¹²³I-meta-iodobenzylguanidine (¹²³I-MIBG) and orthostatic hypotension (OH) are independently associated with worse clinical outcomes of Parkinson’s disease (PD). However, their interactive influence on PD has not been studied. The role of ¹²³I-MIBG myocardial uptake, as a biomarker of PD severity, was investigated, conditional on the mediating effects of OH. A total of 227 PD patients were enrolled. Their motor and nonmotor aspects were assessed with standardized tools. Global disease burden was estimated by averaging the scaled z-scores of the assessment tools. Every patient went through ¹²³I-MIBG scan, and OH was evaluated with the head-up tilt-test. The mediating role of orthostatic blood pressure changes (ΔBP) on the association between cardiac sympathetic denervation and disease burden was investigated. Low heart-to-mediastinum (H/M) ratio with less than 1.78 was seen in 69.6% of the patient population, and 22.9% of patients had OH. Low H/M ratio was associated with OH, and these patients had worse disease burden than subjects with normal ¹²³I-MIBG uptake (global composite z-score: normal ¹²³I-MIBG vs. abnormal ¹²³I-MIBG; −0.3 ± 0.5 vs. 0.1 ± 0.7; p < 0.001). The mediation models, controlled for age and disease duration, revealed that the delayed H/M ratio and global composite score were negatively associated, irrespective of orthostatic ΔBP. Adverse relationship between cardiac sympathetic denervation and disease burden was shown without any interference from orthostatic blood pressure fluctuations. This result suggested that extracranial cardiac markers might reflect disease burden, regardless of labile blood pressure influence.

¹²³ I-间碘苄基胍( ¹²³ I-MIBG)摄取减少和直立性低血压 (OH) 与帕金森病 (PD) 较差的临床结果独立相关。然而，尚未研究它们对 PD 的交互影响。研究了¹²³ I-MIBG 心肌摄取作为 PD 严重程度的生物标志物的作用，条件是 OH 的介导作用。共招募了 227 名 PD 患者。他们的运动和非运动方面使用标准化工具进行评估。通过平均评估工具的缩放 z 分数来估计全球疾病负担。每个病人都经历了¹²³I-MIBG 扫描和 OH 用抬头倾斜测试进行评估。研究了直立性血压变化 (ΔBP) 对心脏交感神经支配与疾病负担之间关联的中介作用。在 69.6% 的患者人群中观察到低于 1.78 的低心脏与纵隔 (H/M) 比值，22.9% 的患者患有 OH。低H / M比用OH相关联，并且这些患者有恶化的疾病负担比与正常人¹²³ I-MIBG摄取（全球复合z得分：正常¹²³ I-MIBG与异常¹²³ I-MIBG; -0.3±0.5对比 0.1 ± 0.7；p < 0.001)。控制年龄和疾病持续时间的中介模型显示，无论直立性 ΔBP 是多少，延迟 H/M 比和总体综合评分呈负相关。心脏交感神经去神经支配与疾病负担之间存在不利关系，不受体位性血压波动的任何干扰。该结果表明，无论不稳定的血压影响如何，颅外心脏标志物可能反映疾病负担。