Left Ventricular Dysfunction Associated With Brain Death: Results From the Donor Heart Study

BACKGROUND

Left ventricular dysfunction in potential donors meeting brain death criteria often results in nonuse of donor hearts for transplantation, yet little is known about its incidence or pathophysiology. Resolving these unknowns was a primary aim of the DHS (Donor Heart Study), a multisite prospective cohort study.

METHODS

The DHS enrolled potential donors by neurologic determination of death (n=4333) at 8 organ procurement organizations across the United States between February 2015 and May 2020. Data included medications administered, serial diagnostic tests, and transthoracic echocardiograms (TTEs) performed: (1) within 48 hours after brain death was formally diagnosed; and (2) 24±6 hours later if left ventricular (LV) dysfunction was initially present. LV dysfunction was defined as an LV ejection fraction <50% and was considered reversible if LV ejection fraction was >50% on the second TTE. TTEs were also examined for presence of LV regional wall motion abnormalities and their reversibility. We assessed associations between LV dysfunction, donor heart acceptance for transplantation, and recipient 1-year survival.

RESULTS

An initial TTE was interpreted for 3794 of the 4333 potential donors by neurologic determination of death. A total of 493 (13%) of these TTEs showed LV dysfunction. Among those donors with an initial TTE, LV dysfunction was associated with younger age, underweight, and higher NT-proBNP (N-terminal pro-B-type natriuretic peptide) and troponin levels. A second TTE was performed within 24±6 hours for a subset of donors (n=224) with initial LV dysfunction; within this subset, 130 (58%) demonstrated reversibility. Sixty percent of donor hearts with normal LV function were accepted for transplant compared with 56% of hearts with reversible LV dysfunction and 24% of hearts with nonreversible LV dysfunction. Donor LV dysfunction, whether reversible or not, was not associated with recipient 1-year survival.

CONCLUSIONS

LV dysfunction associated with brain death occurs in many potential heart donors and is sometimes reversible. These findings can inform decisions made during donor evaluation and help guide donor heart acceptance for transplantation.

Takotsubo cardiomyopathy in patients suffering from acute non-traumatic subarachnoid hemorrhage—A single center follow-up study

Background

Takotsubo cardiomyopathy (TTC) is an important complication of subarachnoid hemorrhage (SAH), that may delay surgical or endovascular treatment and may influence patient outcome. This prospective follow-up study intended to collect data on the prevalence, severity, influencing factors and long-term outcome of TTC in patients suffering from non-traumatic SAH.

Methods

Consecutive patients admitted with the diagnosis of non-traumatic SAH were included. Intitial assessment consisted of cranial CT, Hunt-Hess, Fisher and WFNS scoring, 12-lead ECG, transthoracic echocardiography (TTE), transcranial duplex sonography and collecting laboratory parameters (CK, CK-MB, cardiac troponin T, NT-proBNP and urine metanephrine and normetanephrine). Diagnosis of TTC was based on modified Mayo criteria. TTC patients were dichotomized to mild and severe forms. Follow-up of TTE, Glasgow Outcome Scale assessment, Barthel’s and Karnofsky scoring occurred on days 30 and 180.

Results

One hundred thirty six patients were included. The incidence of TTC in the entire cohort was 28.7%; of them, 20.6% and 8.1% were mild and severe, respectively. TTC was more frequent in females (30/39; 77%) than in males (9/39; 23%) and was more severe. The occurrence of TTC was related to mFisher scores and WFNS scores. Although the severity of TTC was related to mFisher score, Hunt-Hess score, WFNS score and GCS, multivariate analysis showed the strongest relationship with mFisher scores. Ejection fraction differences between groups were present on day 30, but disappeared by day 180, whereas wall motion score index was still higher in the severe TTC group at day 180. By the end of the follow-up period (180 days), 70 (74.5%) patients survived in the non-TTC, 22 (81.5%) in the mild TTC and 3 (27%) in the severe TTC group (n = 11) (p = 0.002). At day 180, GOS, Barthel, and Karnofsky outcome scores were higher in patients in the control (non-TTC) and the mild TTC groups than in the severe TTC group.

Conclusions

Takotsubo cardiomyopathy is a frequent finding in patients with SAH, and severe TTC may be present in 8% of SAH cases. The severity of TTC may be an independent predictor of mortality and outcome at 6 months after disease onset. Therefore, a regular follow-up of ECG and TTE abnormalities is warranted in patients with subrachnoid hemorrhage for early detection of TTC.

Trial registration

The study was registered at the Clinical Trials Register under the registration number of NCT02659878 (date of registration: January 21, 2016).

Distant Organ Damage in Acute Brain Injury

Acute brain injuries pose a great threat to global health, having significant impact on mortality and disability. Patients with acute brain injury may develop distant organ failure, even if no systemic diseases or infection is present. The severity of non-neurologic organs' dysfunction depends on the extremity of the insult to the brain. In this comprehensive review we sought to describe the organ-related consequences of acute brain injuries. The clinician should always be aware of the interplay between central nervous system and non-neurological organs, that is constantly present. Cerebral injury is not only a brain disease, but also affects the body as whole, and thus requires holistic therapeutical approach.

Takotsubo Syndrome: Clinical Features, Pathogenesis, Treatment, and Relationship with Cerebrovascular Diseases

PURPOSE OF REVIEW

This review paper aims to provide a complete and updated overview on the clinical and pathophysiological aspects of Takotsubo syndrome (TTS), including prognosis, therapy, and the association with cerebrovascular conditions.

RECENT FINDINGS

TTS is an increasingly recognized non-ischemic cardiomyopathy characterized by sudden, temporary weakening of the myocardium, of which the pathogenesis is unknown. Although pathogenesis of TTS remains unclear, a complex interaction between catecholamine-mediated stimulation, myocardial stunning, and subsequent stress-related myocardial dysfunction seems to be the main pathophysiological mechanism. Stroke is linked to TTS by a dual relationship since it may induce TTS by catecholamine release even if TTS itself also may be complicated by left ventricular thrombi leading to stroke. Given its possible complications, including the association with neurological diseases, both cardiologist and neurologists should be aware about TTS in order to diagnose it promptly and to initiate appropriate therapeutic measures.

Neurogenic stunned myocardium in subarachnoid hemorrhage

"Stunned myocardium," characterized by reversible left ventricular dysfunction, was first described via animal models using transient coronary artery occlusion. However, this phenomenon has also been noted with neurologic pathologies and collectively been labeled "neurogenic stunned myocardium" (NSM). Neurogenic stunned myocardium resulting from subarachnoid hemorrhage (SAH) is a challenging pathology due to its diagnostic uncertainty. Traditional diagnostic criteria for NSM after SAH focus on electrocardiographic and echocardiographic abnormalities and troponemia. However, tremendous heterogeneity still exists. Traditional pathophysiological mechanisms for NSM encompassed hypothalamic and myocardial perivascular lesions. More recently, research on pathophysiology has centered on myocardial microvascular dysfunction and genetic polymorphisms. Catecholamine surging as a mechanism has also gained attention with particular focus placed on the role of adrenergic blockade in both the prehospital and acute settings. Management remains largely supportive with case reports acknowledging the utility of inotropes such as dobutamine and milrinone and intra-aortic balloon pump when NSM is accompanied by cardiogenic shock. Neurogenic stunned myocardium that follows SAH can result in many complications such as arrhythmias, pulmonary edema, and prolonged intubation, which can negatively impact long-term recovery from SAH and increase morbidity and mortality. This necessitates the need to accurately diagnose and treat NSM.

CNS disease triggering Takotsubo stress cardiomyopathy

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, infectious or immunological encephalitis/meningitis, migraine, and traumatic brain injury. In addition, a number of hereditary and non-hereditary neurodegenerative disorders may impair cardiac functions. Affection of the heart may manifest not only as arrhythmias, myocardial infarction, autonomic impairment, systolic dysfunction/heart failure, arterial hypertension, or pulmonary hypertension, but also as stress cardiomyopathy (Takotsubo syndrome, TTS). CNS disease triggering TTS includes subarachnoid bleeding, epilepsy, ischemic stroke, intracerebral bleeding, migraine, encephalitis, traumatic brain injury, PRES syndrome, or ALS. Usually, TTS is acutely precipitated by stress triggered by various different events. TTS is one of the cardiac abnormalities most frequently induced by CNS disorders. Appropriate management of TTS from CNS disorders is essential to improve the outcome of affected patients.

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.

Clinical characteristics of myocardial stunning in acute stroke

Neurogenic stunned myocardium (NSM) after subarachnoid hemorrhage (SAH) is well known, but there is a paucity of data regarding its occurrence following acute stroke. The aim of this study is to investigate the clinical characteristics of NSM in acute non-hemorrhagic stroke. We performed an electronic literature search with Medline and Google Scholar for English-language articles using the terms "ischemic stroke" along with "stunned myocardium" or "Takotsubo cardiomyopathy". The search resulted in seven case reports/series, but no prospective studies. The mean age of patients with myocardial stunning following ischemic stroke was 72.5 years and 77% of these patients were females. Insular cortex was involved in 38.4% of cases. Mean National Institutes of Health Stroke Scale (NIHSS) score at admission was 12.6 and mean NIHSS at discharge was 10.8. T-wave inversions and ST-segment elevations were noted in 84.6% and 69.2% of patients, respectively. Mean troponin elevation was 0.64 mcg/dL and mean left ventricular ejection fraction (LVEF) was 34.4%. In terms of outcomes, 84.6% of patients had significant improvement in LVEF, mostly within 4 weeks of onset of symptoms. To summarize, NSM was more common in females, with favorable prognosis. Less than half the patients with NSM following stroke had insular involvement. The mean troponin level in NSM after stroke was only half of that seen in SAH. While the lack of prospective studies on NSM in stroke patients precludes drawing further conclusions, more studies are warranted to investigate the risk factors for NSM and the effect on stroke outcomes.

High-dose insulin therapy for neurogenic-stunned myocardium after stroke

A 44-year-old woman with a history of complicated type 2 diabetes mellitus presented with a diagnosis of right-hemispheric ischaemic stroke. She developed acute respiratory distress with radiological evidence of pulmonary oedema. The ECG showed poorly significant ST-segment changes, with a minimal increase of cardiac biomarkers. Echocardiography showed a severely depressed left ventricular function, with also low values of cardiac output at invasive monitoring. The possibility of neurogenic-stunned myocardium was discussed and a metabolic resuscitation with high-dose insulin was proposed. An intravenous bolus of 80 units of insulin (0.72 IU/kg) was followed by a continuous infusion at the rate of 160 IU/h (1.45 IU/kg/h). The treatment led to a rapid and sustained improvement of the haemodynamic condition and was well tolerated. In comparison with dobutamine, insulin had significant inotropic effects without tachycardia. The patient unfortunately died on day 35, from respiratory complications after poor neurological recovery.

Preadmission beta-blockers are associated with decreased incidence of neurogenic stunned myocardium in aneurysmal subarachnoid hemorrhage

BACKGROUND

Neurogenic stunned myocardium (NSM) is a frequent complication of aneurysmal subarachnoid hemorrhage (aSAH), with a significant impact on disease course. The presumed cause is catecholamine surge at the time of aneurysm rupture. Beta-blockers, which reduce the impact of the catecholamine surge, may decrease the risk of developing NSM.

METHODS

A chart review of 234 consecutive patients admitted to the Oregon Health and Science University Neurosurgery service between March 6, 2008 and June 23, 2010 with a diagnosis of aneurysmal SAH was performed. This group was further subdivided by patients who received echocardiograms on admission, by gender, and by the prehospital administration of β-blockers.

RESULTS

One hundred thirty of 234 patients had echocardiograms on or shortly after admission, and 18 of these developed NSM (13.8%). None of the 22 patients taking prehospital β-blockers developed NSM. Using the Fisher exact test to compare the 2 groups, patients who were administered prehospital β-blockers were significantly less likely to develop stunning compared to those who were not (P = .04). After correcting for other variables using multiple logistic regression analysis, the previous use of β-blockers was still found to be significantly associated with a decreased incidence of NSM after SAH (P = .049). There was no significant difference in hospital length of stay, peribleed stroke, vasospasm, or death. Of the 18 patients with stunning, 15 were women, 5 of whom were on estrogen supplementation. The mean peak troponin elevation of women who developed NSM on estrogen supplementation was significantly higher than for those who were not (mean peak troponin 9.97 ± 2.01 mg/dL; P < .001).

CONCLUSION

Prehospital β-blockers are associated with decreased risk of developing NSM in patients with aSAH. Estrogen may play an additional role in shaping the degree of NSM in women.

How to protect the heart in septic shock: a hypothesis on the pathophysiology and treatment of septic heart failure

Heart failure is a well-recognized manifestation of organ failure in sepsis and septic shock. The pathophysiology of septic heart failure is complex and currently believed to involve several mechanisms. So far, the contributory role of high plasma catecholamine levels has not been investigated. In this manuscript, we present a hypothesis suggesting that excessive catecholamine production and exogenous administration of catecholamines may relevantly contribute to the development of heart failure and cardiovascular collapse in patients suffering from septic shock. Substantially elevated plasma catecholamine levels were measured during critical illness and sepsis or septic shock. There is a growing body of clinical and experimental evidence demonstrating that high catecholamine plasma levels exert direct toxic effects on the heart. The pathophysiologic mechanisms involved in catecholamine-induced cardiomyocyte toxicity may involve a combination of inflammation, oxidative stress, and abnormal calcium handling resulting in myocardial stunning, apoptosis and necrosis. Clinical signs of catecholamine-induced heart failure can present with a wide range of symptoms reaching from subtle histological changes with preserved myocardial pump function to severe heart failure exhibiting a distinctive echocardiographic pattern which became known as "Takotsubo"-like cardiomyopathy or the left ventricular apical ballooning syndrome. In a medical intensive care unit patient population, presence of sepsis was the only variable associated with the development of left ventricular apical ballooning. Since several therapeutic interventions influence catecholamine plasma levels in septic shock patients, treatment strategies aiming at the reduction of endogenous or exogenous catecholamine exposure may protect the heart during septic shock and could facilitate patient survival.