Biomarker-guided implementation of angiotensin II to reduce the occurrence of kidney damage after cardiac surgery (Acronym: Angiotensin II to reduce kidney damage (Aided-Trial))

血管麻痹综合征是一种分布性休克，其特征是动脉压降低，全身血管阻力降低，心输出量正常或升高，这种情况发生在5%至25%的心脏手术患者中。心脏手术后血管麻痹休克的患者发生器官衰竭的风险更高，包括急性肾损伤(AKI)。术后(AKI)与几种不良后果相关。到目前为止，预防AKI的努力基本上都是徒劳的。以前的研究通常始于AKI事件后的干预，此时肾功能下降(即肾小球滤过率)已经确定。去甲肾上腺素目前被认为是治疗血管麻痹性休克的一线药物，但所有的儿茶酚胺都有副作用，包括心肌缺血和心律失常。在最近的一项观察性试验中，我们证明了心脏手术后肾素-血管紧张素-醛固酮系统(RAAS)的失调可能是由于血管紧张素转换酶(ACE)活性降低所致。肾素水平升高表明患者有AKI的风险，并与心脏手术后心血管不稳定和AKI发生率增加有关。此外，肾素水平升高可用于确定心血管不稳定和AKI的高危患者，这些患者将受益于血管紧张素II的及时干预，以改善他们的预后。因此，应用血管紧张素II治疗术后低血压将意味着激素替代。在这里，我们想要调查与标准护理对照组相比，在标准护理组中加入血管紧张素II是否在肾脏损害方面更好(个性化的方法)。

Vasoplegic syndrome is a form of distributive shock that is characterized by low arterial pressure with reduced systemic vascular resistance and normal or elevated cardiac output that occurs in 5 to 25% of patients undergoing cardiac surgery. Patients with vasoplegic shock after cardiac surgery are at higher risk of organ failure, including acute kidney injury (AKI). Postsurgical (AKI) is associated with several adverse outcomes. Attempts to prevent AKI have largely been futile so far. Prior studies often started with the interventions after an AKI event, when a decline of kidney function (i.e. glomerular filtration rate) was already established. Application of norepinephrine is currently considered as the first-line therapy for vasoplegic shock, but all catecholamines have adverse effects, including myocardial ischemia and arrhythmias. In a recent observational trial, we demonstrated that there is a dysregulation in the renin-angiotensin-aldosterone system (RAAS) likely caused by a reduced angiotensin-converting enzyme (ACE) activity after cardiac surgery. Elevated renin levels identified patients at risk for AKI and were associated with cardiovascular instability and increased AKI rate after cardiac surgery. Furthermore, elevated renin levels could be used to identify high-risk patients for cardiovascular instability and AKI who would benefit from timely intervention with angiotensin II that could improve their outcomes. Therefore, the application of angiotensin II to treat a postoperative hypotension would mean a hormone substitution. Here, we want to investigate whether adding angiotensin II to standard of care group compared to the standard of care control group is superior with respect to kidney damage (personalized approach).