Sympathetic nervous activity and myocardial damage immediately after subarachnoid hemorrhage in a unique animal model

Troponin elevation in coronary vs. non-coronary disease

Acute myocardial infarction is defined as myocardial cell death due to prolonged myocardial ischaemia. Cardiac troponins (cTn) are the most sensitive and specific biochemical markers of myocardial injury and with the new high-sensitivity troponin methods very minor damages on the heart muscle can be detected. However, elevated cTn levels indicate cardiac injury, but do not define the cause of the injury. Thus, cTn elevations are common in many disease states and do not necessarily indicate the presence of a thrombotic acute coronary syndrome (ACS). In the clinical work it may be difficult to interpret dynamic changes of troponin in conditions such as stroke, pulmonary embolism, sepsis, acute perimyocarditis, Tako-tsubo, acute heart failure, and tachycardia. There are no guidelines to treat patients with elevated cTn levels and no coronary disease. The current strategy of treatment of patients with elevated troponin and non-acute coronary syndrome involves treating the underlying causes. The aim of this paper is to review data from studies of non-ACS patients with acutely elevated troponin who in clinical practice may be difficult to discriminate from ACS patients.

Fundamental increase in pressure-dependent constriction of brain parenchymal arterioles from subarachnoid hemorrhage model rats due to membrane depolarization

Intracerebral (parenchymal) arterioles are morphologically and physiologically unique compared with pial arteries and arterioles. The ability of subarachnoid hemorrhage (SAH) to induce vasospasm in large-diameter pial arteries has been extensively studied, although the contribution of this phenomenon to patient outcome is controversial. Currently, little is known regarding the impact of SAH on parenchymal arterioles, which are critical for regulation of local and global cerebral blood flow. Here diameter, smooth muscle intracellular Ca(2+) concentration ([Ca(2+)](i)), and membrane potential measurements were used to assess the function of intact brain parenchymal arterioles isolated from unoperated (control), sham-operated, and SAH model rats. At low intravascular pressure (5 mmHg), membrane potential and [Ca(2+)](i) were not different in arterioles from control, sham-operated, and SAH animals. However, raising intravascular pressure caused significantly greater membrane potential depolarization, elevation in [Ca(2+)](i), and constriction in SAH arterioles. This SAH-induced increase in [Ca(2+)](i) and tone occurred in the absence of the vascular endothelium and was abolished by the L-type voltage-dependent calcium channel (VDCC) inhibitor nimodipine. Arteriolar [Ca(2+)](i) and tone were not different between groups when smooth muscle membrane potential was adjusted to the same value. Protein and mRNA levels of the L-type VDCC Ca(V)1.2 were similar in parenchymal arterioles isolated from control and SAH animals, suggesting that SAH did not cause VDCC upregulation. We conclude that enhanced parenchymal arteriolar tone after SAH is driven by smooth muscle membrane potential depolarization, leading to increased L-type VDCC-mediated Ca(2+) influx.

Takotsubo cardiomyopathy: a unique cardiomyopathy with variable ventricular morphology

Takotsubo cardiomyopathy is an important differential diagnosis of acute coronary syndrome. It is characterized by normal (or near-normal) coronary arteries, regional wall motion abnormalities that extend beyond a single coronary vascular bed, and often, a precipitating stressor. Variants of the classical left ventricular apical ballooning, including mid- or basal left ventricular wall motion abnormalities, are increasingly recognized. Takotsubo cardiomyopathy is not rare, and heightened awareness of this unique cardiomyopathy likely will lead to a higher reported incidence. Diagnosis of takotsubo cardiomyopathy has important implications for clinical management at presentation and afterward. The long-term prognosis is generally favorable; however, a small subset has potentially life-threatening complications during the initial presentation. The pathophysiologic mechanism is unknown, but catecholamine excess likely has a central role.

Takotsubo cardiomyopathy induced by dobutamine infusion during hypertensive therapy for symptomatic vasospasm after subarachnoid hemorrhage -case report-

A 65-year-old female with subarachnoid hemorrhage (SAH) developed takotsubo cardiomyopathy induced by dobutamine infusion for vasospasm 9 days after onset of SAH. She underwent neck clipping of the ruptured cerebral aneurysm on day 1. Course after surgery was uneventful, but she developed motor aphasia on day 9. Hypertensive therapy was carried out under the diagnosis of symptomatic vasospasm. Half an hour after initiation of dobutamine infusion at 6 microg/kg/min, sudden symptoms of takotsubo cardiomyopathy developed. Fortunately, her symptoms recovered in a few days with supportive therapy without any consequences. Takotsubo cardiomyopathy is one pattern of cardiac dysfunction occasionally encountered after SAH. Possible mechanisms of this disorder include epicardial catecholamine cardiotoxicity. Therefore, generally, cardiac function is worst at the early stage of SAH, when sympathetic activity is highest, and recovers thereafter. Dobutamine infusion seems to have triggered the takotsubo cardiomyopathy in the present patient even 9 days after onset of SAH. Inotropic agents including dobutamine are often used during the course of SAH, and since takotsubo cardiomyopathy can occur in patients with SAH, this complication must be considered.

Management of post-subarachnoid hemorrhage vasospasm

Permanent neurologic injury and death remain common outcomes following aneurysmal subarachnoid hemorrhage. Although many sophisticated techniques are evolving for securing intracranial aneurysms to prevent rebleeding, progress is lagging in the management of posthemorrhagic complications, particularly cerebral vasospasm. Vasospasm can be defined either angiographically, by visible reduction in arterial lumen diameters, or clinically, with signs of focal or regional cerebral ischemia. The relationship between angiographic and clinical vasospasm is not straightforward. The most important known risk factors for developing posthemorrhagic vasospasm include volume and distribution of subarachnoid blood, and no preventive measures have proven effective. Established treatment strategies for vasospasm include hyperdynamic therapy, angioplasty, and selective intra-arterial injection of vasodilators. The vasodilatory approach has been called into question by recent data suggesting that reduction of arterial luminal diameters may be due largely to a proliferative arteriopathy. Novel treatment strategies have focused on protecting the cerebrum, targeting components of the inflammatory cascade, and identifying genetic factors predisposing toward vasospasm, all of which may soon yield new treatment modalities.

Cardiac troponin I elevation in patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

Cardiac dysfunction after aneurysmal subarachnoid hemorrhage (SAH) is associated with elevation of serum cardiac troponin I (cTnI) levels. Elevation of cTnI predicts cardiopulmonary and neurological complications, and poor outcome.

METHODS

We retrospectively reviewed the medical and radiologic records of 114 (male : 30, female : 84) patients who developed aneurysmal SAH between January 2006 and June 2007 and had no history of previous cardiac problems. We evaluated their electrocardiography and cTnI level, which had been measured at admission. A cTnI level above 0.5 microg/L was defined as an indicator of cardiac injury following SAH. We examined various clinical factors for their association with cTnI elevation and analyzed data using chi-square test, t-test and logistic regression test with SPSS version 12.0. The results were considered significant at p < 0.05.

RESULTS

THE FOLLOWING PARAMETERS SHOWS A CORRELATION WITH CTNI ELEVATION : higher Hunt-Hess (H-H) grade (p = 0.000), poor Glasgow Outcome Scale (GOS) score (p = 0.000), profound pulmonary complication (p = 0.043), higher heart rate during initial three days following SAH (p = 0.029), ruptured aneurysm on communicating segment of internal carotid artery (p = 0.025), incidence of vasospasm (p = 0.421), and duration of hyperdynamic therapy for vasospasm (p = 0.292). A significant determinants for outcome were cTnI elevation (p = 0.046) and H-H grade (p = 0.000) in a multivariate study.

CONCLUSION

A cTnI is a good indicator for cardiopulmonary and neurologic complications and outcome following SAH. Consideration of variable clinical factors that related with cTnI elevation may be useful tactics for treatment of SAH and concomitant complications.

Rehabilitation implications of non-traumatic subarachnoid haemorrhage

OBJECTIVE

Subarachnoid haemorrhage (SAH) remains an important cause of stroke in the rehabilitation population, whose incidence has not been changed by pre-morbid medical treatment. The understanding of the pathophysiological changes that occur after SAH has been more clearly defined, therefore the treatment and outcomes of these patients have undergone drastic changes over the past few years. The purpose of this review is to update and familiarize the rehabilitation professional on the state of the art treatment and common complications associated with this disease and how this may affect the rehabilitation programme. Also, the current literature on the outcomes of these patients will be reviewed to help advise the rehabilitation professional on potential predictors.

DATA SOURCES

Literature review.

STUDY SELECTION

Articles of relevance to the current management of SAH.

DATA EXTRACTION

Information that was deemed significant in the understanding of the pathophysiology, treatment and results of outcomes in patients with SAH.

DATA SYNTHESIS

Subarachnoid haemorrhage (SAH) is the one sub-type of stroke whose incidence has not declined. Due to advances in medical care, mortality rate is on the decline. Outcomes data was analysed to look for common predictors for this patient population.

CONCLUSIONS

While the incidence of SAH has not declined, improving medical treatment has reduced mortality. The rehabilitation professional should be familiar with the latest advances, potential complications and likely outcomes in order to plan the most appropriate therapy course for these patients.

B-type natriuretic peptide release and left ventricular filling pressure assessed by echocardiographic study after subarachnoid hemorrhage: a prospective study in non-cardiac patients

INTRODUCTION

Serum B-type natriuretic peptide (BNP) is frequently elevated after subarachnoid hemorrhage (SAH), but whether this high BNP level is related to transient elevation of left ventricular filling pressure (LVFP) is unknown. However, in patients with preexistent cardiac pathologies, it is impossible to differentiate between BNP elevation caused by chronic cardiac abnormalities and BNP related to acute neurocardiac injury.

METHODS

All adult patients with SAH admitted to our intensive care unit were eligible. Patients were excluded for the following reasons: admission >48 hours after aneurysm rupture, pre-existing hypertension, or cardiac disease. Levels of BNP and cardiac troponin Ic were measured daily for 7 days. Echocardiography was performed by a blinded cardiologist on days 1, 2, and 7. Doppler signals from the mitral inflow, tissue Doppler, and the color M-mode-derived flow propagation velocity (FPV) were obtained to assess echo-estimated LVFP.

RESULTS

During a 3-year period, sixty-six consecutive patients with SAH were admitted. Thirty one patients were studied. The BNP level was >100 ng/L in 25 patients (80%) during the first 3 days, with a peak on day 2 (median, 126 ng/L) followed by a gradual decrease (median variation days 1 to 7, 70%). All patients had an ejection fraction >50%. Early transmitral velocity/tissue Doppler mitral annular early diastolic velocity was low: 5.4 (+/- 1.5) on day 1, 5.8 (+/- 1.2) on day 2, and 5.1 (+/- 0.9) on day 7. Early transmitral velocity/FPV was also low: 1.27 (+/- 0.4), 1.25 (+/- 0.3), and 1.1 (+/- 0.2) on days 1, 2, and 7, respectively. Cardiac troponin Ic levels ranged from 0 to 3.67 microg/L and were correlated with BNP (r = 0.63, P < 0.01).

CONCLUSIONS

BNP rises gradually over two days and return to normal within a week after SAH. Its release is associated with myocardial necrosis, but is unrelated to elevated LVFP assessed by echocardiography.

Death from cardiac failure in a child with ruptured cerebral arteriovenous malformation

We present the case of a 13-year-old boy with a ruptured cerebral arteriovenous malformation who had rapidly progressive cardiac failure leading to death. Serial electrocardiograms, cardiac enzymes, echocardiograms, and pulmonary artery catheter data confirmed severe ventricular dysfunction related to myocardial ischemia and infarction. Cardiac dysfunction after cerebral insult is commonly described in adults with aneurysmal subarachnoid hemorrhage and has been termed "neurogenic stunned myocardium" because of its transient nature in most of patients. In children, cardiovascular dysfunction has been described in a few reports and only after traumatic brain injury. No deaths have been reported. This case report illustrates the potentially lethal consequences of cardiovascular dysfunction in children after ruptured cerebral arteriovenous malformation with subarachnoid hemorrhage. Compromised cardiac function should be considered during the early evaluation and management of these patients and supportive care instituted to limit secondary brain injury from poor perfusion.

Relationship between sympathetic nervous activity and inflammatory response after subarachnoid hemorrhage in a perforating canine model

The objective of the present study was to evaluate the correlation between sympathetic nerve activation and inflammatory response in the acute stage of subarachnoid hemorrhage (SAH) in a canine perforating model. SAH was induced by perforation of the basilar artery with the use of a microcatheter via the femoral artery in 20 mongrel dogs. Hemodynamic parameters and intracranial pressure were recorded, and blood sample for C3a, C5b-9, IL-6, IL-8 and noradrenaline kinetic determination were measured at 0, 5, 15, 30, 60, 120, and 180 min after SAH. Noradrenaline (pg/mL) increased abruptly from 104+/-59 to 2010+/-918 at 5 min after SAH. C3a and C5b-9 reached peak values at 15 min and IL-6 and IL-8 reached peak values at 30 min after SAH, respectively. The peak values of C3a and C5b-9 correlated positively with the peak value of noradrenaline (r=0.743 and r=0.753, respectively). The peak values of IL-6 and IL-8 also correlated positively with the peak values of noradrenaline (r=0.603 and r=0.681, respectively).These results suggest that a pronounced activation of the sympathetic nervous system and the inflammatory response occurs in acute stage of SAH. Significant association between the rate of spillover of norepinephrine to plasma and the plasma levels of inflammatory markers indicates that the two processes, sympathetic activation and immune response are quantitatively linked in early stage after SAH. The exact mechanisms underlying this phenomenon deserved further investigations.

Ventricular arrhythmia risk after subarachnoid hemorrhage

INTRODUCTION

Cardiac morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH) are attributable to myocardial injury, decreased ventricular function, and ventricular arrhythmia (VA). Our objective was to test the relationships between QTc prolongation, VA, and survival after SAH.

METHODS

In 200 subjects with acute aneurysmal SAH, electrocardiograms, echocardiograms, and telemetry were evaluated. Serum electrolytes and troponin were also evaluated.

RESULTS

Initial QTc (mean 460 +/- 45 ms) was prolonged (> or = 470 ms) in 38% of subjects and decreased on follow-up (469 +/- 49 initial vs. 435 +/- 31 ms follow-up; N = 89; P < 0.0001). VA was present in 14% of subjects, 52% of subjects with VA had QTc > or = 470 ms, and initial QTc trended toward longer duration in subjects with VA (474 +/- 61 vs. 457 +/- 42 ms; P = 0.084). Multivariate analysis demonstrated significant predictors of VA after SAH were increasing age (OR 1.3/5 years; P = 0.025), increasing stroke severity (OR 1.8; P = 0.009), decreasing heart rate (OR 0.5/10 beats/min; P = 0.006), and the absence of angiotensin converting enzyme inhibitor or angiotensin II receptor antagonist use at SAH onset (OR 0.10; P = 0.027). All-cause mortality was 19% (25/135) at 3 months and subjects with VA had significantly higher mortality than those without VA (37% vs. 16%; P = 0.027).

CONCLUSIONS

These data demonstrate that QTc prolongation and arrhythmias are frequently noted after SAH, but arrhythmias are often not associated with QTc prolongation. In addition, the presence of VA identified subjects at greater risk of mortality following their SAH.

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.

Myocardial contrast echocardiography in subarachnoid hemorrhage-induced cardiac dysfunction: case report

OBJECTIVE

Cardiac dysfunction is a well-known complication of aneurysmal subarachnoid hemorrhage (SAH) that is generally regarded as secondary to catecholamine excess rather than overt ischemia. Myocardial contrast echocardiography (MCE) is a novel method of evaluating cardiac function and perfusion. We report the use of MCE in a patient with SAH and correlate the results to coronary angiography.

METHODS

Bedside MCE using Definity contrast agent (Bristol-Myers Squibb/Sanofi Pharmaceuticals, New York, NY) was performed at the onset of SAH and at the 1-week and 4-month follow-up evaluations.

RESULTS

A 64-year-old woman presented with aneurysmal SAH. She developed transient ST elevation on lateral electrocardiographic leads and elevated cardiac enzymes with creatine-kinase MB isoenzyme of 44.3 ng/ml and troponin of 0.62 ng/ml. An emergent coronary angiogram performed at the outside facility revealed normal coronary anatomy, ejection fraction of 30%, and midventricular akinesis. On transfer to our facility, MCE demonstrated an ejection fraction of 45% with normal coronary perfusion in the akinetic midventricular segments and normally contracting basal and apical segments. At the 4-month follow-up examination, her ejection fraction normalized to 67% and regional wall motion had improved.

CONCLUSION

To our knowledge, our case represents the first reported use of MCE in a patient with SAH. MCE demonstrating normal myocardium perfusion in the setting of normal coronary arteries on coronary angiogram and midventricular akinetic segments is compatible with nonischemic injury, which further supports the "catecholamine hypothesis" of neurogenic cardiac stunning. MCE may be a feasible noninvasive method to evaluate myocardial perfusion in the SAH population.

Intensive care management of patients with subarachnoid haemorrhage

PURPOSE OF REVIEW

The aim of this article is to summarize recent concepts regarding the intensive care management of patients with subarachnoid haemorrhage, emphasizing the detection and treatment of cerebral vasospasm and the management of systemic complications.

RECENT FINDINGS

Aneurysmal subarachnoid haemorrhage is a potentially devastating disease that requires complex treatment strategies and extended monitoring. The prognosis of subarachnoid haemorrhage depends on the severity of the initial bleed, the success of the procedure to secure the aneurysm and the occurrence and severity of sequelae, including cerebral vasospasm. Patients with subarachnoid haemorrhage benefit from multidisciplinary neurointensive care where management is targeted at securing the ruptured aneurysm, optimizing cardiovascular variables, detecting and treating cerebral vasospasm and managing systemic complications.

SUMMARY

The complex treatment strategies applied after subarachnoid haemorrhage call for interdisciplinary collaboration between neurosurgeons, neuroradiologists, neurointensivists and specialist nurses. Specialized neuromonitoring and neuroimaging techniques must also be available. The neurointensive care unit serves as the focal point for these combined efforts.

Cardiac troponin is the most effective translational safety biomarker for myocardial injury in cardiotoxicity

There is an overwhelming weight of evidence that certifies cardiac troponin (cTn) as the preferred, defacto, translational, safety biomarker for myocardial injury in cardiotoxicity. As well as being the gold standard for cardiac injury in man, it has been widely used for clinical assessment and monitoring of cardiac toxicity in humans being treated for cancer. Furthermore, several dozen preclinical published studies have directly confirmed its effectiveness in laboratory animals for assessment of cardiotoxicity. It is gradually being reverse translated from human into animal use as a safety biomarker. Its use is especially merited whenever there is any safety signal indicating potential cardiotoxicity and its required inclusion as a routine biomarker in preclinical safety studies seems on the horizon. There are some considerations that are unique to use of cTn assays in animals. Lack of awareness of these has, historically, significantly inhibited the introduction of cTn as a safety biomarker in preclinical toxicology. Firstly, cross-species reactivity is usually but not always high. Secondly, there is a background of cardiac injury that needs to be controlled for, including spontaneous cardiomyopathy in Sprague Dawley rats, and inappropriate blood collection methods. Also, there are faster kinetics of clearance in rats than for humans. Also, coincident muscle injury is frequent with cardiotoxicity and requires a skeletal muscle biomarker. Because cTn assays were developed for detection of gross cardiac necrosis, such as occurs with myocardial infarct, the more sensitive assays should be used for preclinical studies. However, analytic sensitivity is higher for standard preclinical studies than for clinical diagnostic testing because of use of concurrent controls and use of batch analysis that eliminates interassay variability. No other biomarker of myocardial injury comes close to cTn in effectiveness, including CK-MB, LDH-1 and 2, myoglobin, and FABP3. In addition to the use of cTn for monitoring active myocardial degeneration, there is growing evidence that measurements of brain natriuretic peptide (BNP) may be effective for monitoring drug-induced left ventricular dysfunction.

Myocardial stress in patients with acute cerebrovascular events

Signs of myocardial involvement are common in patients with acute cerebrovascular events. ST segment deviations, abnormal left ventricular function, increased N-terminal pro-brain natriuretic peptide (NT-proBNP), prolonged QT interval, and/or raised troponins are observed in up to one third of the patients. The huge majority of these findings are fully reversible. The changes may mimic myocardial infarction, but are not necessarily identical to coronary thrombosis. Based on the literature these signs may represent an acute catecholamine release provoked by the cerebrovascular catastrophe itself and not coronary thrombosis. However, all patients with signs of cardiac involvement during acute cerebrovascular events should receive a cardiological follow-up in order to exclude concomitant ischemic heart disease.

The systemic implications of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is analogous to a pathophysiological watershed, disrupting brain integrity and function and precipitating an array of systemic derangements including cardiovascular, respiratory, endocrine, hematological, and immune dysfunction. Extracerebral organ dysfunction is closely linked to the magnitude of the primary neurological insult, suggesting neurogenic, neuroendocrine and neuroimmunomodulatory mechanisms. Systemic organ involvement is associated with increased mortality and neurological impairment, even after adjustment for other outcome predictors such as the severity of the initial neurological injury. This may be a reflection of secondary brain injury precipitated by hypoxemia, circulatory failure, fever, or hyperglycemia, all of which have been linked to adverse clinical outcomes. Interventions to avert or reverse these and other perturbations need to be tested in clinical trials as they represent opportunities to improve survival and neurological recovery in patients with SAH.

[Cerebral salt wasting syndrome: experimental study in rats]

INTRODUCTION

The cerebral salt wasting syndrome (CSWS) is characterized by hyponatraemia secondary to excessive natriuesis with osmotic duiresis. This syndrome, frequently, occurs after subarachnoid haemorrhage (SAH), but may occur after any acute cerebral aggression.

OBJECTIVES

The aim of the study was to assess the frequency of the CSWS in animal models with, SAH, cerebral ischemia (CI), and cranial trauma (CT), and its correlation with the secretion of brain natriuretic peptide (BNP).

METHOD

Four groups of rats were selected: group SAH (n=7) consisted of SAH induced by perforation of the carotid artery in its intracerebral part; group CI (n=7) consisted of CI induced by ligature of the carotid artery; group CT (n=7) consisted of induced CT; and a control group Sham (n=7). Weight, serum sodium, BNP, and urinary sodium, were measured at baseline and 24 hours after.

RESULTS

Rats with SAH had significant natriuresis and diuresis with negative sodium balance (-95.9+/-447.4 mumol) with a significant difference (P<0.05) compared to the rats of the CI and the Sham groups. There was no difference in the 24 hours level of BNP between the four different groups.

CONCLUSION

We conclude that SAH, in animal models, induced high diuresis with negative sodium balance in the first 24 hours. These findings were absents in the others groups. This was independent of the BNP secretion and may correspond to the early occurrence of a CSWS.

Mechanisms in neurogenic stress cardiomyopathy after aneurysmal subarachnoid hemorrhage

Cardiac dysfunction after aneurysmal subarachnoid hemorrhage (SAH) is often referred to as "neurogenic stunned myocardium," which does not accurately reflect the suspected pathophysiology. We propose an alternative terminology, "neurogenic stress cardiomyopathy," as a more appropriate label based on our review of the current literature. This article will review the distinctive characteristics of SAH-induced cardiac dysfunction, hypotheses to explain the pathophysiology, and the supporting clinical and animal studies. Recognition of the unique features associated with SAH-induced cardiac complications allows optimal management of patients with SAH. We will also discuss the clinical and theoretical overlap of SAH-induced cardiac dysfunction with a syndrome known as tako-tsubo cardiomyopathy and explore therapeutic opportunities.

Cardiac complications after aneurysmal subarachnoid hemorrhage

BACKGROUND

Cardiac complications are frequently encountered by neurointensivists caring for patients with SAH. Our aim was to better characterize the natural history of various cardiac abnormalities in this population. We sought to determine the risk factors for cardiac abnormalities, patient outcome, and impact of treatment type on cardiac abnormalities.

METHODS

We performed a single center retrospective review of admissions of patients with aneurysmal SAH to the neurosurgical ICU in a large university hospital. Patient demographics, pertinent history, cardiac tests, hospital LOS, intervention type, and discharge outcome were collected.

RESULTS

Data from 266 patients were available for analysis. Of these patients, 50% (n = 133) demonstrated cardiac abnormalities as indicated by abnormal EKG, ECHO, or troponin I. Only age was determined to be an independent statistically significant predictor of cardiac abnormality (P = .01). There was no difference in mortality between the cardiac abnormality and control groups (P = .33). However, there was increased morbidity in the cardiac abnormality group as demonstrated by worse discharge disposition, in addition to increased length of hospital stay (22.6 vs 17.1 days, P < .01). The incidence of cardiac abnormalities was the same among surgical and endovascular treatment groups.

CONCLUSIONS

Cardiac abnormalities, including those that meet ACC criteria for MI, are common among patients with SAH. However, in contrast to cardiac events outside the context of SAH, these abnormalities do not increase mortality. They do, however, adversely affect discharge disposition and prolong hospital LOS. The type of aneurysm treatment does not affect the incidence or outcome of cardiac abnormalities.

Tako-tsubo cardiomyopathy in aneurysmal subarachnoid hemorrhage: an underappreciated ventricular dysfunction

OBJECT

Neurogenic stunned myocardium in aneurysmal subarachnoid hemorrhage (SAH) is associated with a wide spectrum of reversible left ventricular wall motion abnormalities and includes a subset of patients with a pattern of apical akinesia and concomitant sparing of basal segments called "tako-tsubo cardiomyopathy".

METHODS

After obtaining institutional review board approval, the authors retrospectively identified among all patients admitted to the Mayo Clinic's Neurological Intensive Care Unit between January 1990 and January 2005 those with aneurysmal SAH who had met the echocardiographic criteria for tako-tsubo cardiomyopathy. Among 24 patients with SAH-induced reversible cardiac dysfunction, the authors identified eight with SAH-induced tako-tsubo cardiomyopathy. All eight patients were women with a mean age of 55.5 years (range 38.6-71.1). Seven patients presented with a poor-grade SAH, reflected by a Hunt and Hess grade of III or IV. Four patients underwent aneurysm clip application, and four underwent endovascular coil occlusion. The initial mean ejection fraction (EF) was 38% (range 25-55%), and the mean EF at recovery was 55% (range 40-68%). Cerebral vasospasm developed in six patients, but cerebral infarction developed in only three patients.

CONCLUSIONS

The authors describe the largest cohort with aneurysmal SAH-induced tako-tsubo cardiomyopathy. In the SAH population, tako-tsubo cardiomyopathy predominates in postmenopausal women and is often associated with pulmonary edema, prolonged intubation, and cerebral vasospasm. Additional studies are warranted to understand the complex mechanism involved in tako-tsubo cardiomyopathy and its intriguing relationship to neurogenic stunned myocardium.

Chronic hydrocephalus-induced changes in cerebral blood flow: mediation through cardiac effects

Decreased cerebral blood flow (CBF) in hydrocephalus is believed to be related to increased intracranial pressure (ICP), vascular compression as the result of enlarged ventricles, or impaired metabolic activity. Little attention has been given to the relationship between cardiac function and systemic blood flow in chronic hydrocephalus (CH). Using an experimental model of chronic obstructive hydrocephalus developed in our laboratory, we investigated the relationship between the duration and severity of hydrocephalus and cardiac output (CO), CBF, myocardial tissue perfusion (MTP), and peripheral blood flow (PBF). Blood flow measures were obtained using the microsphere injection method under controlled hemodynamic conditions in experimental CH (n=23) and surgical control (n=8) canines at baseline and at 2, 4, 8, 12, and 16 weeks. Cardiac output measures were made using the Swan-Ganz thermodilution method. Intracranial compliance (ICC) via cerebrospinal fluid (CSF) bolus removal and infusion, and oxygen delivery in CSF and prefrontal cortex (PFC) were also investigated. We observed an initial surgical effect relating to 30% CO reduction and approximately 50% decrease in CBF, MTP, and PBF in both groups 2 weeks postoperatively, which recovered in control animals but continued to decline further in CH animals at 16 weeks. Cerebral blood flow, which was positively correlated with CO (P=0.028), showed no significant relationship with either CSF volume or pressure. Decreased CBF correlated with oxygen deprivation in PFC (P=0.006). Cardiac output was inversely related with ventriculomegaly (P=0.019), but did not correlate with ICP. Decreased CO corresponded to increased ICC, as measured by CSF infusion (P=0.04). Our results suggest that CH may have more of an influence on CO and CBF in the chronic stage than in the early condition, which was dominated by surgical effect. The cause of this late deterioration of cardiac function in hydrocephalus is uncertain, but may reflect cardiac regulation secondary to physiologic response or brain injury. The relationship between cardiac function and CBF should be considered in the pathophysiology and clinical treatment of CH.

High-dose norepinephrine induces disruption of myocardial extracellular matrix and left ventricular dilatation and dysfunction in a novel feline model

BACKGROUND

Intravenous norepinephrine (NE) at a dose of 1-6 microg/kg/minute can induce increased extracellular matrix (ECM) and hypertrophic cardiomyopathy. This study aimed to investigate the effects of a higher dose of NE on cardiac remodeling.

METHODS

After intraperitoneal urethane-chloralose anesthesia, 7 cats (3.03 +/- 0.58 kg) received intravenous infusion of NE 30 microg/kg/minute for 3 hours. Aortic blood pressure and heart rate (HR) were measured by polygraphy at 0, 5, 15, 30, 60, 90, 120, and 180 minutes. Left ventricular size and ejection fraction (EF) were measured by M-mode echocardiography before and after NE administration. Histopathology was performed by hematoxylin-eosin, silver impregnation, and Sirius red staining. Activity of matrix metalloproteinases (MMP) in the left ventricle was measured by zymography.

RESULTS

Mean blood pressure (mmHg) increased from 139 +/- 20 to 198 +/- 19, 187 +/- 23, and 166 +/- 16 at 15, 30, and 60 minutes, respectively, during NE infusion. HR (beats/minute) decreased from 214 +/- 10 to 158 +/- 28 at 15 minutes and then recovered gradually. The left ventricles showed significant dilatation (end-diastolic diameter: from 1.20 +/- 0.18 to 1.58 +/- 0.23cm, p=0.003; end-systolic diameter: from 0.62 +/- 0.23 to 1.35 +/- 0.29cm, p=0.002) and hypokinesia (EF: from 86.2 +/- 5.2 to 33.1 +/- 16.5%, p < 0.001). Histopathology revealed that left ventricular myocytes were elongated, wavy, and fragmented, while collagen fibers were overstretched, straightened, and disrupted. MMP-9 activity was significantly elevated (p = 0.003 vs. control), while MMP-2 activity was unchanged.

CONCLUSION

High-dose NE increases MMP-9 activity and causes ECM disruption, left ventricular dilatation and dysfunction.

Elevated plasma N-terminal pro-brain natriuretic peptide levels in acute ischemic stroke

BACKGROUND

B-type natriuretic peptide (BNP) is a neurohormone secreted mainly in the cardiac ventricles in response to volume expansion and pressure overload. The aim of this study was to assess plasma N-terminal proBNP (NT-proBNP) changes in acute ischemic stroke (AIS).

METHODS

The study group consisted of 57 (37 women aged 64 +/- 12 years) patients who had their first AIS and no history or signs of cardiovascular disease. An age-matched control group was also included (n = 57, 36 women aged 61 +/- 6 years). NT-proBNP, troponin I (TnI), and creatine kinase-MB were evaluated. A thorough cardiovascular and neurological investigation, including imaging techniques and lesion size determination, was also performed.

RESULTS

The log NT-proBNP peak levels, TnI, and creatine kinase-MB levels were significantly higher in AIS compared with controls (7.25 +/- 1.77 vs 3.48 +/- 0.76 pg/mL, P < .0001; 0.76 +/- 0.54 vs 0.5 +/- 0.0 ng/mL, P < .001; 57 +/- 37 vs 13 +/- 4 U/L, P < .001, respectively). The log NT-proBNP correlated positively with TnI (r = 0.29, P = .03) and heart rate (r = 0.41, P = .002), and negatively with left ventricular ejection fraction (r = -0.67, P < .0001). Patients with signs of marked myocardial ischemia and patients with insular cortex involvement had even higher NT-proBNP levels. After adjustment for relevant factors, the relation between the log NT-proBNP and AIS as well as insular cortex involvement was observed to be insignificant (P > .05 for both).

CONCLUSIONS

Our results show that NT-proBNP plasma levels are significantly elevated in AIS and might be of clinical importance as a supplementary tool for the assessment of cardiovascular function in patients with AIS.

Controversies in the management of aneurysmal subarachnoid hemorrhage*

BACKGROUND

The care of patients with aneurysmal subarachnoid hemorrhage has evolved significantly with the advent of new diagnostic and therapeutic modalities. Although it is believed that these advances have contributed to improved outcomes, considerable uncertainty persists regarding key areas of management.

OBJECTIVE

To review selected controversies in the management of aneurysmal subarachnoid hemorrhage, with a special emphasis on endovascular vs. surgical techniques for securing aneurysms, the diagnosis and therapy of cerebral vasospasm, neuroprotection, antithrombotic and anticonvulsant agents, cerebral salt wasting, and myocardial dysfunction, and to suggest venues for further clinical investigation.

DATA SOURCE

Search of MEDLINE and Cochrane databases and manual review of article bibliographies.

DATA SYNTHESIS AND CONCLUSIONS

Many aspects of care in patients with aneurysmal subarachnoid hemorrhage remain highly controversial and warrant further resolution with hypothesis-driven clinical or translational research. It is anticipated that the rigorous evaluation and implementation of such data will provide a basis for improvements in short- and long-term outcomes.

Extracerebral organ dysfunction in the acute stage after aneurysmal subarachnoid hemorrhage

In patients with aneurysmal subarachnoid hemorrhage (SAH), secondary complications are an important cause of morbidity and case fatality. Delayed cerebral ischemia and hydrocephalus are important intracranial secondary complications. Potentially treatable extracranial complications are also frequently observed, and some are related to the occurrence of delayed cerebral ischemia and outcome. In addition to the occurrence of an inflammatory response and metabolic derangements, cardiac and pulmonary complications are the most common extracranial complications. This article provides an overview of the most common extracranial complications in patients with SAH and describes their effects on outcome and delayed cerebral ischemia.

Terson's Syndrome as the Initial Symptom of Subarachnoid Hemorrhage Caused by Ruptured Vertebral Artery Aneurysm-Case Report-

A 61-year-old male initially presented to the ophthalmology department complaining of sudden visual loss. Fundus photography and ultrasonography followed by computed tomography identified Terson's syndrome caused by subarachnoid hemorrhage (SAH). Cerebral angiography revealed a dissecting aneurysm of the left vertebral artery. Other than obtunded visual acuity, his neurological examination was normal and he denied any headache. He was treated conservatively with pain and blood pressure control. He complained of headache associated with rerupture of the aneurysm on day 5. The patient died of rerupture on day 14. The clinical course of this patient indicates that Terson's syndrome may occur without sudden increase of intracranial pressure. Terson's syndrome may occur as a rare initial clinical sign of SAH caused by ruptured cerebral aneurysm.

Troponin I in predicting cardiac or pulmonary complications and outcome in subarachnoid haemorrhage

BACKGROUND

Patients with aneurysmal subarachnoid haemorrhage (SAH) are at risk of cardiac and pulmonary complications. Troponin I (cTnI), a reliable marker of myocardial injury, is frequently raised after SAH.

AIMS

To investigate the additional value of (cTnI) in predicting cardiac or pulmonary complications and outcome in patients with SAH.

METHODS

Admission cTnI was measured in a prospective series of patients admitted within 24 hours of SAH. By means of univariate and multivariate logistic regression models the additional prognostic value of raised cTnI (>0.3 microg/litre) was investigated compared with established prognosticators (clinical condition on admission, age, and amount of blood on admission computed tomography) for predicting the occurrence of pulmonary oedema, pulmonary gas exchange abnormalities, rhythm disturbances, inadequate cardiac performance, a combination of these complications, and poor outcome. Area under the operator characteristic curve (AUC-ROC) was used to assess additional prognostic value.

RESULTS

Abnormal cTnI concentrations were found on admission in 35 of 68 patients. Abnormal cTnI concentrations and poor clinical condition independently predicted cardiac or pulmonary complications. After extending the model with World Federation of Neurological Surgeons scale and age in addition to abnormal cTnI, the AUC-ROC improved from 0.70 (95% confidence interval (CI), 0.57 to 0.83) to 0.83 (95% CI, 0.72 to 0.93). Abnormal cTnI also independently predicted poor outcome. The additional prognostic value of cTnI for poor outcome is limited.

CONCLUSIONS

cTnI measurement is a powerful predictor for the occurrence of pulmonary and cardiac complications, but does not carry additional prognostic value for clinical outcome in patients with aneurysmal SAH.

Neurogenic pulmonary edema during intracranial endovascular therapy

Neurogenic pulmonary edema (NPE) is a well-known complication of acute brain injury. Neurogenic stunned myocardium (NSM) occurs clinically in a significant subset of patients with NPE. A 49-year-old woman developed refractory cerebral vasospasm requiring angioplasty following a subarachnoid hemorrhage. During angioplasty, NPE with NSM manifested as acute pulmonary edema associated with elevated pulmonary artery occlusion pressure and reduced cardiac output. Evaluations disclosed a right insular infarction, cardiac wall motion abnormalities, and electrocardiographic characteristics of NSM. The NSM completely resolved, and the neurological outcome was good. A 56-year-old woman developed NPE during complicated coil embolization of an internal carotid artery aneurysm. Cardiac function was normal, and the NPE resolved with a brief period of mechanical ventilation and diuresis. The delayed appearance of NSM and NPE during endovascular therapy in these patients implies a degree of risk for sympathetically mediated cardiopulmonary dysfunction during complex intracranial endovascular procedures.

Sympathetic activity and myocardial damage after stimulation of dorsal medulla and vagotomy in a novel animal model

Many kinds of brain lesions cause sympathetic hyperexcitation and myocardial damage. A novel animal model was developed for the correlation of sympathetic excitation with ventricular dysfunction and myocardial damage. Six cats (3.23+/-0.26 kg) under intraperitoneal urethane-chloralose anesthesia were artificially ventilated and bilaterally vagotomized. They underwent an electrical stimulation of unilateral dorsal medulla for 180 min (monopolar square-wave pulses, 10 Hz, 10 V, 0.5 ms). Mean blood pressure, heart rate plasma concentration of norepinephrine and left ventricular size and ejection fraction were measured at 0, 5, 15, 30, 60, 90, 120 and 180 min. Mean blood pressure (mm Hg), heart rate (beats/min) and norepinephrine (pg/ml) increased abruptly from 128+/-15, 203+/-22 and 353+/-123 to 234+/-26, 240+/-13 and 4727+/-2159 at 5 min after electrical stimulation (all p<0.01). The left ventricles showed significant dilatation (end-diastolic diameter: from 1.35+/-0.13 to 1.84+/-0.21 cm, p=0.006; end-systolic diameter: from 0.65+/-0.20 to 1.54+/-0.24 cm, p=0.002) and hypokinesia (ejection fraction: from 88.9+/-6.4% to 37.3+/-8.7%, p<0.001). Cardiac pathology revealed myocardial hemorrhage, cardiomyocyte apoptosis and coagulative myocytolysis (contraction band necrosis), characterized by sarcoplasmic coagulation, granulation and disruption. In conclusions, the present experiment develops a novel animal model in which stimulation of the pressor area in the dorsal medulla in vagotomized cats produces sympathetic hyperexcitation accompanied with myocardial dysfunction and damage. This model may be applicable for studying protective effect of drugs on myocardial dysfunction and damage caused by sympathetic hyperexcitation occurring in brain diseases.

Effects of body weight-supported treadmill training on heart rate variability and blood pressure variability in individuals with spinal cord injury

Individuals with spinal cord injury are prone to cardiovascular dysfunction and an increased risk of cardiovascular disease. Body weight-supported treadmill training (BWSTT) may enhance ambulation in individuals with incomplete spinal cord injury; however, its effects on cardiovascular regulation have not been investigated. The purpose of this study was to examine the effects of 6-mo of BWSTT on the autonomic regulation of heart rate (HR) and blood pressure (BP) in individuals with incomplete tetraplegia. Eight individuals [age 27.6 yr (SD 5.2)] with spinal cord injury [C4–C5; American Spinal Injury Association B-C; 9.6 yr (SD 7.5) postinjury] participated. Ten-minute HR and finger arterial pressure (Finapres) recordings were collected during 1) supine rest and 2) an orthostatic stress (60° head-up tilt) before and after 6 mo of BWSTT. Frequency domain measures of HR variability [low-frequency (LF) power, high-frequency (HF) power, and LF-to-HF ratio] and BP variability (systolic and diastolic LF power) were used as clinically valuable indexes of neurocardiac and neurovascular control, respectively. There was a significant reduction in HR [61.9 (SD 6.9) vs. 55.7 beats/min (SD 7.7); P = 0.05] and LF-to-HF ratio [1.23 (SD 0.47) vs. 0.99 (SD 0.40); P < 0.05] after BWSTT. There was a significant reduction in LF systolic BP [183.1 (SD 46.8) vs. 158.4 mmHg2 (SD 45.2); P < 0.01] but no change in BP. There were no significant effects of training on HR variability or BP variability during 60° head-up tilt. In conclusion, individuals with incomplete tetraplegia retain the ability to make positive changes in cardiovascular autonomic regulation with BWSTT without worsening orthostatic intolerance.

Age and aneurysm position predict patterns of left ventricular dysfunction after subarachnoid hemorrhage

Cardiac injury, including left ventricular dysfunction, frequently occurs in patients with subarachnoid hemorrhage. Patterns of left ventricular dysfunction often do not follow coronary artery distributions, and may correlate with myocardial sympathetic innervation. Left ventricular dysfunction of the anterior and anteroseptal walls that spares the apex is unusual for patients with myocardial infarction and may represent a neurally mediated pattern of injury. We performed serial echocardiography on 225 patients with subarachnoid hemorrhage and classified those with regional wall-motion abnormalities as following either an apex-sparing (AS) or apex-affected (AA) pattern. Wall-motion abnormalities were found in 61 of 225 patients studied (27%). The AS pattern was found in 49% of these patients. Younger age and anterior aneurysm position were independent predictors of this AS pattern. Both patterns of wall-motion abnormalities appear to be transient, reversible phenomena. The AS pattern may represent a unique form of neurally mediated cardiac injury.

Ampulla (takotsubo) cardiomyopathy associated with subarachnoid hemorrhage worsening in the late phase of vasospasm--case report

A 66-year-old woman presented with subarachnoid hemorrhage(SAH) caused by a ruptured aneurysm of the left middle cerebral artery. Electrocardiography (ECG) disclosed abnormalities resembling acute myocardial infarction. She underwent neck clipping of the aneurysm uneventfully. Sixteen days after admission, ECG again disclosed abnormalities resembling acute myocardial infarction, and echocardiography suggested heart failure. Coronary angiography showed no abnormalities, but left ventriculography showed severe hypokinesia in the apex of the heart consistent with so-called ampulla (takotsubo) cardiomyopathy. The heart failure was treated with catecholamines and her heart function gradually recovered. Ampulla (takotsubo) cardiomyopathy associated with SAH requires careful management of heart function.

Diagnosis of subarachnoid hemorrhage indicated by transthoracic echocardiography

We report the case of a 63-year-old woman who presented to her local emergency department unresponsive and in a state of cardiogenic shock 4 hours after the sudden onset of a severe headache. Her electrocardiogram revealed nonprogressive 1-mm S-T elevation in leads V(5) to V(6) and a prolonged QTc. A transthoracic echocardiogram performed at the time of her resuscitation revealed regional wall-motion abnormalities not consistent with any known coronary artery territory but consistent with a diagnosis of acute subarachnoid hemorrhage. This diagnosis was subsequently confirmed on computed tomography brain imaging. Although subarachnoid hemorrhage is known to be associated with cardiopulmonary dysfunction, and electrocardiogram and echocardiogram abnormalities, the diagnosis of subarachnoid hemorrhage suspected by echocardiography before brain imaging has not previously been described.