Left ventricular myocardial function during the acute phase of a subarachnoid haemorrhage

The Role of Serum Monocytes and Tissue Macrophages in Driving Left Ventricular Systolic Dysfunction and Cardiac Inflammation Following Subarachnoid Hemorrhage

BACKGROUND

Neurocardiogenic injury is common after aneurysmal subarachnoid hemorrhage (aSAH) despite low prevalence of preexisting cardiac disease. Potential mechanisms include autonomic dysregulation due to excess catecholamines as well as systemic inflammation. Understanding how inflammation contributes to cardiac dysfunction may aid in identifying novel therapeutic strategies. Here, we investigated serum leukocytes as predictors of left ventricular systolic dysfunction in patients with aSAH. We also investigated increased cardiac macrophages in an animal model of SAH and whether immunomodulatory treatment could attenuate this inflammatory response.

METHODS

We retrospectively analyzed 256 patients with aSAH admitted to University of Illinois Hospital between 2013 and 2019. Our inclusion criteria included patients with aSAH receiving an echocardiogram within 72 h of admission. Our primary outcome was echocardiographic evidence of systolic dysfunction. We performed multinomial regression and receiver operating curve analysis. We also used the endovascular perforation model of SAH in male Sprague-Dawley rats to assess for myocardial inflammation. Two days after surgery, hearts were collected and stained for the macrophage marker Iba-1. We compared the presence and morphology of macrophages in cardiac tissue isolated from SAH animals and sham controls treated with and without the immunomodulatory agent fingolimod.

RESULTS

Of 256 patients with aSAH, 233 (91.0%) underwent echocardiography within 72 h of admission. Of 233, 81 (34.7%) had systolic dysfunction. Patients had baseline differences in the presence of hypertension, alcohol use, and admission Glasgow Coma Scale and Hunt-Hess score. On multivariable analysis, total leukocytes (odds ratio 1.312, p < 0.001), neutrophils (odds ratio 1.242, p = 0.012), and monocytes (odds ratio 6.112, p = 0.008) were independent predictors of reduced systolic function, whereas only monocytes (odds ratio 28.014, p = 0.030) predicted hyperdynamic function. Within the rodent heart, there were increased macrophages after SAH relative to controls, and this was attenuated by fingolimod treatment (p < 0.0001).

CONCLUSIONS

Increased serum leukocytes are associated with abnormal left ventricular systolic function following aSAH. The strongest independent predictor of both reduced and hyperdynamic systolic function was increased monocytes. Increased cardiac macrophages after experimental SAH can also be targeted by using immunomodulatory drugs.

Advanced monitoring of systemic hemodynamics in critically ill patients with acute brain injury

Hemodynamic monitoring is widely used in critical care; however, the impact of such intervention in patients with acute brain injury (ABI) remains unclear. Using PubMed, a systematic review was performed (1966-August 2013), and 118 studies were included. Data were extracted using the PICO approach. The evidence was classified, and recommendations were developed according to the GRADE system. Electrocardiography and invasive monitoring of arterial blood pressure should be the minimal hemodynamic monitoring required in unstable or at-risk patients in the intensive care unit. Advanced hemodynamic monitoring (i.e., assessment of preload, afterload, cardiac output, and global systemic perfusion) could help establish goals that take into account cerebral blood flow and oxygenation, which vary depending on diagnosis and disease stage. Choice of techniques for assessing preload, afterload, cardiac output, and global systemic perfusion should be guided by specific evidence and local expertise. Hemodynamic monitoring is important and has specific indications among ABI patients. Further data are necessary to understand its potential for therapeutic interventions and prognostication.

CNS-disease affecting the heart: brain-heart disorders

There are a number of hereditary and non-hereditary central nervous system (CNS) disorders, which directly or indirectly affect the heart (brain-heart disorders). The most well-known of these CNS-disorders are epilepsy, stroke, subarachanoid bleeding, bacterial meningitis, and head injury. In addition, a number of hereditary and non-hereditary neurodegenerative disorders may impair cardiac functions. Affection of the heart may manifest as arrhythmias, cardiomyopathy, or autonomic dysfunction. Rarer cardiac complications of CNS disorders include heart failure, systolic or diastolic dysfunction, myocardial infarction, arterial hypertension, or pulmonary hypertension. Cardiomyopathy induced by hereditary CNS disease mainly include stress-induced myocardial dysfunction, known as Takotsubo syndrome (TTS). CNS disease triggering TTS includes epilepsy, ischemic stroke, subarachnoid bleeding, or PRES syndrome. Arrhythmias induced by hereditary CNS disease include supraventricular or ventricular arrhythmias leading to palpitations, dizziness, vertigo, fainting, syncope, (near) sudden cardiac death, or sudden unexplained death in epilepsy (SUDEP). Appropriate management of cardiac involvement in CNS-disorders is essential to improve outcome of affected patients.