Frequency, predictors, and neurologic outcomes of vaso-occlusive strokes associated with cardiac surgery in children

Risk, clinical features, and outcomes of thrombosis associated with pediatric cardiac surgery

BACKGROUND

Thrombosis, usually considered a serious but rare complication of pediatric cardiac surgery, has not been a major clinical and/or research focus in the past.

METHODS AND RESULTS

We noted 444 thrombi (66% occlusive, 60% symptomatic) in 171 of 1542 surgeries (11%). Factors associated with increased odds of thrombosis were age <31 days (odds ratio [OR], 2.0; P=0.002), baseline oxygen saturation <85% (OR, 2.0; P=0.001), previous thrombosis (OR, 2.6; P=0.001), heart transplantation (OR, 4.1; P<0.001), use of deep hypothermic circulatory arrest (OR, 1.9 P=0.01), longer cumulative time with central lines (OR, 1.2 per 5-day equivalent; P<0.001), and postoperative use of extracorporeal support (OR, 5.2; P<0.001). Serious complications of thrombosis occurred with 64 of 444 thrombi (14%) in 47 of 171 patients (28%), and were associated with thrombus location (intrathoracic, 45%; extrathoracic arterial, 19%; extrathoracic venous, 8%; P<0.001), symptomatic thrombi (OR, 8.0; P=0.02), and partially/fully occluding thrombi (OR, 14.3; P=0.001); indwelling access line in vessel (versus no access line) was associated with lower risk of serious complications (OR, 0.4; P=0.05). Thrombosis was associated with longer intensive care unit (+10.0 days; P<0.001) and hospital stay (+15.2 days; P<0.001); higher odds of cardiac arrest (OR, 4.9; P<0.001), catheter reintervention (OR, 3.3; P=0.002), and reoperation (OR, 2.5; P=0.003); and increased mortality (OR, 5.1; P<0.001). Long-term outcome assessment was possible for 316 thrombi in 129 patients. Of those, 197 (62%) had resolved at the last follow-up. Factors associated with increased odds of thrombus resolution were location (intrathoracic, 75%; extrathoracic arterial, 89%; extrathoracic venous, 60%; P<0.001), nonocclusive thrombi (OR, 2.2; P=0.01), older age at surgery (OR, 1.2 per year; P=0.04), higher white blood cell count (OR, 1.1/10(9) cells per 1 mL; P=0.002), and lower fibrinogen (OR, 1.4/g/L; P=0.02) after surgery.

CONCLUSIONS

Thrombosis affects a high proportion of children undergoing cardiac surgery and is associated with suboptimal outcomes. Increased awareness and effective prevention and detection strategies are needed.

Lipopolysaccharide-induced preconditioning against ischemic injury is associated with changes in toll-like receptor 4 expression in the rat developing brain

Lipopolysaccharide (LPS) preconditioning reduces ischemic injury in adult brain by activating Toll-like receptor 4 (TLR-4). We sought to investigate the effect of brain maturity on the efficacy of LPS preconditioning against hypoxic-ischemic (HI) injury in the developing rat brain. Rat pups at the specified age were randomly assigned to LPS-treated (0.1 mg/kg) or saline-treated groups. HI injury was induced 48 h later by occluding the right common carotid artery followed by transient hypoxia. Brains were removed 1 wk after HI injury, and infarct volumes were compared between the two groups. TLR-4 expression was also compared among different ages. We found that LPS treated P7, P9, and P14 rat pups had significantly smaller infarct volume compared with saline-treated pups (p = 0.006, 0.03, and 0.01, respectively). This significant reduction in infarct volume was not observed in P3 and P5 rats. TLR-4 expression was significantly higher in older rats compared with P3 and P5 rats (p < 0.01). These findings indicate that LPS-induced preconditioning is a robust neuroprotective phenomenon in the ischemic developing brain that is age dependent. Pattern of TLR-4 expression is also affected by brain maturity and likely to be responsible for differences in the efficacy of LPS preconditioning.

Current proceedings of childhood stroke

Stroke is a sudden onset neurological deficit due to a cerebrovascular event. In children, the recognition of stroke is often delayed due to the low incidence of stroke and the lack of specific assessment measures to this entity. The causes of pediatric stroke are significantly different from that of adult stroke. The lack of safety and efficiency data in the treatment is the challenge while facing children with stroke. Nearly half of survivors of pediatric stroke may have neurologic deficits affecting functional status and quality of life. They may cause a substantial burden on health care resources. Hence, an accurate history, including onset and duration of symptoms, risk factors, and a complete investigation, including hematologic, neuroimaging, and metabolic studies is the key to make a corrective diagnosis. A prompt and optimal treatment without delay may minimize the damage to the brain.

Neurologic complications of cardiac surgery and interventional cardiac procedures

Neurologic complications of cardiac surgery and interventional cardiac procedures may affect the central nervous system or the peripheral nervous system. The most common central nervous system complications are strokes and seizures. This article provides a succinct neuroanatomic and pathophysiologic approach to a wide array of neurologic complications associated with cardiac procedures.

New approaches to neuroprotection in infant heart surgery

Advances in surgical techniques and perioperative management have led to dramatic improvements in outcomes for children with complex congenital heart disease (CHD). As the number of survivors continues to grow, clinicians are becoming increasingly aware that adverse neurodevelopmental outcomes after surgical repair of CHD represent a significant cause of morbidity, with widespread neuropsychologic deficits in as many as 50% of these children by the time they reach school age. Modifications of intraoperative management have yet to measurably impact long-term neurologic outcomes. However, exciting advances in our understanding of the underlying mechanisms of cellular injury and of the events that mediate endogenous cellular protection have provided a variety of new potential targets for the assessment, prevention, and treatment of neurologic injury in patients with CHD. In this review, we will discuss the unique challenges to developing neuroprotective strategies in children with CHD and consider how multisystem approaches to neuroprotection, such as ischemic preconditioning, will be the focus of ongoing efforts to develop new diagnostic tools and therapies. Although significant challenges remain, tremendous opportunity exists for the development of diagnostic and therapeutic interventions that can serve to limit neurologic injury and ultimately improve outcomes for infants and children with CHD.

Epidemiology of childhood stroke in Estonia

We investigated the incidence and 30-day case-fatality of childhood stroke in Estonia, and clinical signs and risk factors of childhood stroke. A retrospective (1995-2003) and prospective study (2004-2006) of childhood stroke (arterial ischemic, hemorrhagic, and sinovenous thrombosis) and transient ischemic attack was conducted. Stroke-incidence calculation was based on the prospective study. Clinical diagnoses of stroke were confirmed by neuroradiology. The incidence rate of childhood stroke in Estonia was 2.73/100,000 person-years for children aged 30 days to 18 years: 1.61/100,000 for arterial ischemic stroke, 0.87/100,000 for hemorrhagic stroke, 0.25/100,000 for sinovenous thrombosis, and 0.37/100,000 for transient ischemic attack. No arterial ischemic stroke patients died within 30 days, but case-fatality for intracerebral hemorrhage was 46%. Focal signs occurred in 100% of arterial ischemic strokes and 64% of intracerebral hemorrhage cases. Risk factors were identified in 35/48 (73%) children with cerebrovascular attacks. Six children with arterial ischemic stroke (6/24, 25%) manifested more than one risk factor. The incidence rate of childhood stroke in Estonia is similar to that in earlier data.

Stroke and cerebrovascular disorders

PURPOSE OF REVIEW

Stroke and cerebrovascular disorders in childhood are a cause for significant morbidity in childhood. There is growing emphasis on understanding the mechanisms of stroke so as to inform developments in investigation and management.

RECENT FINDINGS

Advances have been made in the classification of pediatric stroke, aided by clinical and radiological recognition of patterns of injury and differential outcomes dependent on timing of stroke occurrence. Risk factors are multifactorial, with evidence of geographical and national variation. Causality, however, remains difficult to prove. Recent studies highlight a significant association between stroke recurrence and outcome and the presence of steno-occlusive arterial disease, Moyamoya disease and progressive arteriopathy. Focal arteriopathy of childhood is a new term proposed to refine the nomenclature of childhood arteriopathy. The association between infection and childhood stroke is increasingly recognized, with associations with sinovenous thrombosis and childhood arteriopathy. The recommendation to screen for arteriopathy in genetic conditions such as sickle cell disease is now extended to include children with neurofibromatosis type 1. Perfusion and magnetic resonance wall imaging have helped in the determination of the cause of stroke with impact on management in adults. Two new treatment guidelines have been published (American Heart Association and Chest), but barriers remain to the use of thrombolysis in childhood stroke.

SUMMARY

Continued developments in understanding and practice in childhood stroke are encouraging. However, the absence of clinical trials and evidence-based guidelines is limiting. The conduct of such trials is a goal towards which the International Pediatric Stroke Study is moving.

Epidemiology and classification of perinatal stroke

Stroke is an important cause of mortality and chronic morbidity in infants and children. Case definitions for perinatal stroke have varied among studies by clinical and laboratory criteria. A recent US National Institutes of Health workshop on perinatal stroke provided consensus recommendations on the definition and classification of perinatal stroke. The incidence of perinatal stroke has been estimated at 1 in 1600 to 5000 births. The clinical presentation of perinatal stroke depends on the time of diagnosis, acute or delayed, but most will present with seizures. Risk factors for perinatal stroke have not been well studied. Several maternal and neonatal disorders have been reported in infants with perinatal stroke. Children who suffer perinatal stroke typically develop long-term disabilities including motor deficits, cognitive and behavioral disorders, and epilepsy. More than half will develop long-term motor or cognitive problems and the recurrence rate after perinatal stroke is very low.

Acute brain injury and therapeutic hypothermia in the PICU: A rehabilitation perspective

Acquired brain injury from traumatic brain injury, cardiac arrest (CA), stroke, and central nervous system infection is a leading cause of morbidity and mortality in the pediatric population and reason for admission to inpatient rehabilitation. Therapeutic hypothermia is the only intervention shown to have efficacy from bench to bedside in improving neurological outcome after birth asphyxia and adult arrhythmia-induced CA, thought to be due to its multiple mechanisms of action. Research to determine if therapeutic hypothermia should be applied to other causes of brain injury and how to best apply it is underway in children and adults. Changes in clinical practice in the hospitalized brain-injured child may have effects on rehabilitation referral practices, goals and strategies of therapies offered, and may increase the degree of complex medical problems seen in children referred to inpatient rehabilitation.