Legg Ditterline Bonnie E, Wade Shelley, Ugiliweneza Beatrice, Singam Narayana Sarma, Harkema Susan J, Stoddard Marcus F, Hirsch Glenn A
Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.
Department of NeuroSurgery, University of Louisville, Louisville, KY, United States.
Front Neurosci. 2020 Oct 22;14:554018. doi: 10.3389/fnins.2020.554018. eCollection 2020.
Cardiac myocyte atrophy and the resulting decreases to the left ventricular mass and dimensions are well documented in spinal cord injury. Therapeutic interventions that increase preload can increase the chamber size and improve the diastolic filling ratios; however, there are no data describing cardiac adaptation to chronic afterload increases. Research from our center has demonstrated that spinal cord epidural stimulation (scES) can normalize arterial blood pressure, so we decided to investigate the effects of scES on cardiac function using echocardiography. Four individuals with chronic, motor-complete cervical spinal cord injury were implanted with a stimulator over the lumbosacral enlargement. We assessed the cardiac structure and function at the following time points: (a) prior to implantation; (b) after scES targeted to increase systolic blood pressure; (c) after the addition of scES targeted to facilitate voluntary (i.e., with intent) movement of the trunk and lower extremities; and (d) after the addition of scES targeted to facilitate independent, overground standing. We found significant improvements to the cardiac structure (left ventricular mass = 10 ± 2 g, < 0.001; internal dimension during diastole = 0.1 ± 0.04 cm, < 0.05; internal dimension during systole = 0.06 ± 0.03 cm, < 0.05; interventricular septum dimension = 0.04 ± 0.02 cm, < 0.05), systolic function (ejection fraction = 1 ± 0.4%, < 0.05; velocity time integral = 2 ± 0.4 cm, < 0.001; stroke volume = 4.4 ± 1.5 ml, < 0.01), and diastolic function (mitral valve deceleration time = -32 ± 11 ms, < 0.05; mitral valve deceleration slope = 50 ± 25 cm s, < 0.05; isovolumic relaxation time = -6 ± 1.9 ms, < 0.05) with each subsequent scES intervention. Despite the pilot nature of this study, statistically significant improvements to the cardiac structure, systolic function, and diastolic function demonstrate that scES combined with task-specific interventions led to beneficial cardiac remodeling, which can reverse atrophic changes that result from spinal cord injury. Long-term improvements to cardiac function have implications for increased quality of life and improved cardiovascular health in individuals with spinal cord injury, decreasing the risk of cardiovascular morbidity and mortality.
脊髓损伤时,心肌细胞萎缩以及由此导致的左心室质量和尺寸减小已有充分记录。增加前负荷的治疗干预措施可增大心腔大小并改善舒张期充盈率;然而,尚无关于心脏对慢性后负荷增加的适应性的数据。我们中心的研究表明,脊髓硬膜外刺激(scES)可使动脉血压正常化,因此我们决定使用超声心动图研究scES对心脏功能的影响。4例慢性、运动完全性颈髓损伤患者在腰骶膨大处植入了刺激器。我们在以下时间点评估了心脏结构和功能:(a)植入前;(b)以升高收缩压为目标进行scES后;(c)添加以促进躯干和下肢自主(即有意)运动为目标的scES后;(d)添加以促进独立的地面站立为目标的scES后。我们发现,随着每次后续的scES干预,心脏结构(左心室质量 = 10 ± 2 g,< 0.001;舒张期内径 = 0.1 ± 0.04 cm,< 0.05;收缩期内径 = 0.06 ± 0.03 cm,< 0.05;室间隔厚度 = 0.04 ± 0.02 cm,< 0.05)、收缩功能(射血分数 = 1 ± 0.4%,< 0.05;速度时间积分 = 2 ± 0.4 cm,< 0.001;每搏输出量 = 4.4 ± 1.5 ml,< 0.01)和舒张功能(二尖瓣减速时间 = -32 ± 11 ms,< 0.05;二尖瓣减速斜率 = 50 ± 25 cm/s,< 0.05;等容舒张时间 = -6 ± 1.9 ms,< 0.05)均有显著改善。尽管本研究具有探索性质,但心脏结构、收缩功能和舒张功能的统计学显著改善表明,scES联合特定任务干预可导致有益的心脏重塑,从而逆转脊髓损伤引起的萎缩性变化。心脏功能的长期改善对提高脊髓损伤患者的生活质量和改善心血管健康具有重要意义,可降低心血管疾病的发病率和死亡率。