Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Republic of Korea.
Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea.
J Thorac Cardiovasc Surg. 2022 Aug;164(2):528-535.e2. doi: 10.1016/j.jtcvs.2020.08.083. Epub 2020 Sep 1.
The safe ischemic time after a single-dose del Nido cardioplegia (DNC) infusion has not yet been established. This study evaluated the progression of myocardial ischemic injury to establish the safe ischemic time after a single-dose DNC infusion in the human heart using a transmission electron microscope.
Seven hearts extracted from heart transplant recipients after infusion of 1000 mL single-dose DNC were evaluated. Serial left ventricular myocardial tissue samples were collected every 30 minutes for 180 minutes. Ischemic injuries in the mitochondria and nuclei were scored from 0 to 3 (0 = normal, 0.5 = slight, 1 = moderate, 2 = severe, and 3 = irreversible).
At the time of extraction, 83.5% of the mitochondria were normal. The proportion of mitochondria with moderate ischemic injury increased gradually from 1.4% at extraction to 52.5% at 180 minutes. From 90 minutes to 180 minutes, the proportion of mitochondria with severe and irreversible injury increased from 0.8% to 4.4% and 0.3% to 1.3%, respectively. A significant linear correlation was identified between the average ischemic injury score of mitochondria and ischemic time (P < .001). Most nuclei showed moderate to severe ischemic injury at every time point (61.0%-85.2%). A significant linear correlation was also found between the average ischemic injury score of nuclei and ischemic time (P < .001).
Myocardial ischemic injury progresses gradually, and irreversible ischemic injury begins to occur 90 minutes after initial DNC infusion in the adult human heart. Therefore, redosing of DNC may be required after 90 minutes of aortic crossclamp time during adult cardiac surgery.
单次推注 Del Nido 心脏停搏液（DNC）后的安全缺血时间尚未确定。本研究使用透射电子显微镜评估心肌缺血损伤的进展，以确定单次推注 DNC 后人心肌的安全缺血时间。
评估了从心脏移植受者体内输注 1000 毫升单次剂量 DNC 后提取的 7 颗心脏。每 30 分钟收集连续的左心室心肌组织样本，持续 180 分钟。对线粒体和核的缺血损伤从 0 到 3 分进行评分（0=正常，0.5=轻微，1=中度，2=严重，3=不可逆）。
在提取时，83.5%的线粒体正常。从中度缺血损伤的线粒体比例从提取时的 1.4%逐渐增加到 180 分钟时的 52.5%。从 90 分钟到 180 分钟，严重和不可逆损伤的线粒体比例从 0.8%增加到 4.4%和 0.3%增加到 1.3%。线粒体平均缺血损伤评分与缺血时间之间存在显著的线性相关性（P<.001）。大多数核在每个时间点都显示出中度到重度的缺血损伤（61.0%-85.2%）。核平均缺血损伤评分与缺血时间之间也存在显著的线性相关性（P<.001）。
心肌缺血损伤逐渐进展，在成人心脏初次 DNC 输注后 90 分钟开始出现不可逆性缺血损伤。因此，在成人心脏手术中，主动脉阻断时间超过 90 分钟后，可能需要重新给予 DNC 剂量。
