Neurogenic cardiac injury

Neurogenic stunned myocardium resulting from surgical brainstem handling during resection of paediatric recurrent medulloblastoma-a possible brain heart interaction

BACKGROUND

Neurogenic stunned myocardium (NSM) is characterised by an acute onset cardiac dysfunction following an acute neurological insult which mimics acute coronary syndrome.

CASE DETAILS

A 12-year-old male child was admitted to the neuro-intensive care unit (NICU) following midline suboccipital craniotomy and resection of recurrent medulloblastoma. Postoperatively, in NICU, he developed tachycardia and hypotension, which was unresponsive to fluid challenge requiring norepinephrine infusion. Intraoperatively, during tumour resection from the dorsal medulla, episodes of hypertension and bradycardia were observed. Intraoperative blood loss was adequately managed with a stable hemodynamic profile without postoperative anaemia. An electrocardiogram showed sinus tachycardia with T wave inversion, and blood investigation revealed elevated cardiac troponin T levels. Point of care ultrasound (POCUS) of heart and lung showed features of NSM. Infusion dobutamine was added to achieve a target mean arterial pressure of 65 mm Hg with concomitant furosemide infusion and fluid restriction. Daily POCUS assessment of cardiac contractility and volume status was done. The patient was weaned from vasoactive drugs and ventilator following improvement of cardiac function and was discharged from NICU after 17 days.

CONCLUSION

NSM results from the excessive release of catecholamines following stimulation of trigger zones in the brain. To date, a handful of cases of pediatric NSM following primary brain tumour are reported where hydrocephalus resulted in trigger zone activation. In this presented case, direct brain stem stimulation during tumour resection might have triggered NSM. Irrespective of the cause, timely diagnosis and execution of supportive management in our patient resulted in a positive outcome.

Head Rules Over the Heart: Cardiac Manifestations of Cerebral Disorders

The Brain-Heart interaction is becoming increasingly important as the underlying pathophysiological mechanisms become better understood. "Neurocardiology" is a new field which explores the pathophysiological interplay of the brain and cardiovascular systems. Brain-heart cross-talk presents as a result of direct stimulation of some areas of the brain, leading to a sympathetic or parasympathetic response or it may present as a result of a neuroendocrine response attributing to a clinical picture of a sympathetic storm. It manifests as cardiac rhythm disturbances, hemodynamic perturbations and in the worst scenarios as cardiac failure and death. Brain-Heart interaction (BHI) is most commonly encountered in traumatic brain injury and subarachnoid hemorrhage presenting as dramatic electrocardiographic changes, neurogenic stunned myocardium or even as ventricular fibrillation. A well-known example of BHI is the panic disorders and emotional stress resulting in Tako-tsubo syndrome giving rise to supraventricular and ventricular tachycardias and transient left ventricular dysfunction. In this review article, we will discuss cardiovascular changes caused due to the disorders of specific brain regions such as the insular cortex, brainstem, prefrontal cortex, hippocampus and the hypothalamus; neuro-cardiac reflexes namely the Cushing's reflex, the Trigemino-cardiac reflex and the Vagal reflex; and other pathological states such as neurogenic stunned myocardium /Takotsubo cardiomyopathy. There is a growing interest among intensivists and anesthesiologists in brain heart interactions as there are an increasing number of cases being reported and there is a need to address unanswered questions, such as the incidence of these interactions, the multifactorial pathogenesis, individual susceptibility, the role of medications, and optimal management.

KEY MESSAGES

BHI contribute in a significant way to the morbidity and mortality of neurological conditions such as traumatic brain injury, subarachnoid hemorrhage, cerebral infarction and status epilepticus. Constant vigilance and a high index of suspicion have to be exercised by clinicians to avoid misdiagnosis or delayed recognition. The entire clinical team involved in patient care should be aware of brain heart interaction to recognize these potentially life-threatening scenarios.

HOW TO CITE THIS ARTICLE

Hrishi AP, Lionel KR, Prathapadas U. Head Rules Over the Heart: Cardiac Manifestations of Cerebral Disorders. Indian J Crit Care Med 2019;23(7):329-335.

Troponin I as an Early Biomarker of Cardiopulmonary Parameters Within the First 24 Hours After Nontraumatic Subarachnoid Hemorrhage in Intensive Care Unit Patients

OBJECTIVE

The elevation of serum cardiac troponin I (TNI) in patients with nontraumatic subarachnoid hemorrhage (ntSAH) is a well-known phenomenon. However, the relation between elevated TNI and different cardiopulmonary parameters (CPs) within the first 24 hours after ntSAH is unknown. The present study was conducted to investigate the association between TNI and different CP in patients with ntSAH within the first 24 hours of intensive care unit (ICU) treatment.

PATIENTS AND METHODS

We retrospectively analyzed a consecutive group of 117 patients with ntSAH admitted to our emergency department between January 2008 and February 2017. Blood samples were taken to determine TNI values on admission. Demographic data, baseline Glasgow Coma Scale (GCS) score, World Federation of Neurosurgical Societies (WFNS) score, baseline Fisher grade (FG), norepinephrine application rate (NAR) in µg/kg/min, and inspiratory oxygen fraction (OF) were recorded within the first 24 hours.

RESULTS

An increased TNI value was found in 32 (27.4%) of 117 patients. There was a significant correlation between initial elevated TNI and a low WFNS score (P = .007), a low GCS score (P = .003) as well as a high OF (P = <.001). The FG (P = .27) and NAR (P = .08) within the first 24 hours of ICU treatment did not show any significant correlation.

CONCLUSIONS

In the present study, an increased TNI value was significantly associated with a low WFNS score and GCS score on admission. The TNI was a predictor of the need for a higher OF within the first 24 hours after ntSAH so that TNI could be an informative biomarker to improve ICU therapy.

Protective Effect of Ischemic Preconditioning on Myocardium Against Remote Tissue Injury Following Transient Focal Cerebral Ischemia in Diabetic Rats

Background

Remote ischemic preconditioning (IPreC) could provide tissue-protective effect at a remote site by anti-inflammatory, neuronal, and humoral signaling pathways.

Objectives

The aim of the study was to investigate the possible protective effects of remote IPreC on myocardium after transient middle cerebral artery occlusion (MCAo) in streptozotocin- induced diabetic (STZ) and non-diabetic rats.

Methods

48 male Spraque Dawley rats were divided into eight groups: Sham, STZ, IPreC, MCAo, IPreC+MCAo, STZ+IPreC, STZ+MCAo and STZ+IPreC+MCAo groups. We induced transient MCAo seven days after STZ-induced diabetes, and performed IPreC 72 hours before transient MCAo. Remote myocardial injury was investigated histopathologically. Bax, Bcl2 and caspase-3 protein levels were measured by Western blot analysis. Total antioxidant status (TAS), total oxidant status (TOS) of myocardial tissue were measured by colorimetric assay. Oxidative stress index(OSI) was calculated as TOS-to-TAS ratio. For all statistical analysis, p values < 0.05 were considered significant.

Results

We observed serious damage including necrosis, congestion and mononuclear cell infiltration in myocardial tissue of the diabetic and ischemic groups. In these groups TOS and OSI levels were significantly higher; TAS levels were lower than those of IPreC related groups (p < 0.05). IPreC had markedly improved histopathological alterations and increased TAS levels in IPreC+MCAo and STZ+IPreC+MCAo compared to MCAo and STZ+MCAo groups (p < 0.05). In non-diabetic rats, MCAo activated apoptotic cell death via increasing Bax/Bcl2 ratio and caspase-3 levels. IPreC reduced apoptotic cell death by suppressing pro-apoptotic proteins. Diabetes markedly increased apoptotic protein levels and the effect did not reversed by IPreC.

Conclusions

We could suggest that IPreC attenuates myocardial injury via ameliorating histological findings, activating antioxidant mechanisms, and inducing antiapoptotic activity in diabetic rats.

Brain-heart crosstalk: the many faces of stress-related cardiomyopathy syndromes in anaesthesia and intensive care

Neurogenic stress cardiomyopathy (NSC) is a well-known syndrome complicating the early phase after an acute brain injury, potentially affecting outcomes. This article is a review of recent data on the putative role of localization and lateralization of brain lesions in NSC, cardiac innervation abnormalities, and new polymorphisms and other genetic causes of the sympathetic nervous system over-activity. Concerns regarding the management of stress-related cardiomyopathy syndromes during the perioperative period are also discussed. Future clinical research should explore whether specific factors explain different patient susceptibilities to the disease and should be directed towards early identification and stratification of patients at risk, so that such patients can be more carefully monitored and appropriately managed in critical care and during the perioperative period.

Optimization of donor management goals yields increased organ use

Multiple strategies have been used in an effort to increase the pool of organs for transplantation. Standardizing donor management has produced promising results. Donor management goals (DMGs) are now being used as end points of intensive care unit care during the prerecovery phase but no prospective results have been reported. Data from the United Network for Organ Sharing Region 11 were collected for successful achievement of eight common donor management goals (mean airway pressure [MAP], central venous pressure [CVP], pH, PaO2, sodium, glucose, single pressor use, and urine output) before organ recovery. Two time periods were studied with different panels of DMGs. The analysis identified the success rate of transplantation. Goals were stratified by their statistical correlation with the number of organs transplanted per donor (OTPD) in an effort to identify the most important parameter(s). Eight hundred five organ donors were studied with 2685 organs transplanted. DMGs were assessed through two phases of the study. Achieving DMGs rose from 18 to 66 per cent associated with significant improvement in OTPD (range, 2.96 to 3.45). The success of transplantation was primarily associated with limitations in vasopressor use and PaO2. Tight glucose control did affect the rate of pancreatic transplants. Thoracic organs were the most sensitive to DMGs with a 10- to 15-fold increase in lung transplantation when PaO2 rose above 100 mmHg. MAP, CVP, pH, sodium, and urine output had little effect on transplantation. Standardization of end points of donor management was associated with increased rates of transplantation. Surprisingly, not all standard goals are necessary for optimal organ use. The most significant parameters were the low use of vasopressor agents and oxygenation. Donor management strategies should strive to optimize these goals.

Relation of elevation in cardiac troponin I to clinical severity, cardiac dysfunction, and pulmonary congestion in patients with subarachnoid hemorrhage

An increase in cardiac troponin I (cTnI) occurs often after aneurysmal subarachnoid hemorrhage (SAH), but its significance is not well understood. One hundred three patients with SAH were prospectively evaluated in the SAHMII Study to determine the relations of cTnI to clinical severity, systolic and diastolic cardiac function, pulmonary congestion, and length of intensive care unit stay. Echocardiographic ejection fraction, wall motion score, mitral inflow early diastolic (E) and mitral annular early (E') velocities were assessed. Thirty patients (29%) had mildly positive cTnI (0.1 to 1.0 ng/ml), 24 (23%) had highly positive cTnI (>1.0 ng/ml), and 49 (48%) had negative cTnI (<0.1 ng/ml). Highly positive cTnI was associated with worse neurologic disease, longer intensive care unit stay, and slight depression of ejection fraction (51 +/- 11% [p <0.05] vs 59 +/- 8% and 63 +/- 6% in mildly positive or negative cTnI groups, respectively). Highly positive cTnI was also associated with abnormal wall motion acutely (>1.31 ng/ml; 76% sensitivity, 91% specificity), which typically resolved within 5 to 10 days. Both mildly or highly positive cTnI were associated with acute diastolic dysfunction, with E/E' of 17 +/- 6 and 16 +/- 6 (both p <0.05) vs 13 +/- 4 in patients with negative cTnI. Prevalences of pulmonary congestion were 79% (p <0.05) in patients with highly positive cTnI, 53% (p <0.05) in patients with mildly positive cTnI, and 29% in cTnI-negative patients. In conclusion, highly positive cTnI with SAH was associated with clinical neurologic severity, systolic and diastolic cardiac dysfunction, pulmonary congestion, and longer intensive care unit stay. Even mild increases in cTnI were associated with diastolic dysfunction and pulmonary congestion.

Neurocardiogenic injury in neurovascular disorders

cardiac injury occurs frequently after stroke; and the most widely investigated form of neurocardiogenic injury is aneurysmal subarachnoid hemorrhage. Echocardiography and screening for elevated troponin and B-type natriuretic peptide levels may help prognosticate and guide treatment of stroke. Cardiac catheterization is not routinely recommended in subarachnoid hemorrhage patients with left ventricular dysfunction and elevated troponin. The priority should be treatment of the underlying neurologic condition, even in patients with left ventricular dysfunction. Cardiac injury that occurs after subarachnoid hemorrhage appears to be reversible. In contrast to subarachnoid hemorrhage patients, patients with ischemic stroke are more likely to have concomitant significant heart disease. For patients who develop brain death, cardiac evaluation under optimal conditions may help increase the organ donor pool.