(Stroke. 2002;33:1671.)
© 2002 American Heart Association, Inc.
Original Contributions |
From the Department of Rehabilitation (T.M., A.M., S.O., Y.S., S.S.), School of Allied Health Sciences, and Departments of Internal Medicine (K.S., N.M., T.S., T.I.) and Emergency and Critical Care Medicine (S.Y.), School of Medicine, Kitasato University, Sagamihara, Japan.
Correspondence to Takashi Masuda, MD, Department of Rehabilitation, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 228-8555, Japan. E-mail tak9999{at}med.kitasato-u.ac.jp
| Abstract |
|---|
|
|
|---|
Methods SAH was provoked by perforation of the basilar artery with the use of a microcatheter inserted through the femoral artery in 18 beagle dogs. Hemodynamic changes were recorded, and plasma concentrations of noradrenaline, adrenaline, and 3-methoxy-4-hydroxy-phenylethylene glycol (MHPG) and serum levels of creatine kinaseMB (CK-MB) and troponin T were measured at 0, 5, 15, 30, 60, 120, and 180 minutes after SAH.
Results Noradrenaline (pg/mL), adrenaline (pg/mL), and MHPG (ng/mL) increased abruptly from 120±70, 130±70, and 1.3±0.5 before SAH to 1700±1200, 5600±3500, and 3.2±1.2 at 5 minutes after SAH, respectively. Aortic pressure, left ventricular wall motion, and cardiac output increased by 60%, 40%, and 30%, respectively (P<0.001) at 5 minutes and then decreased by 50%, 55%, and 40%, respectively (P<0.001) >60 minutes after SAH compared with baseline values. The peak value of CK-MB correlated positively with the peak values of noradrenaline and adrenaline (r=0.730 and r=0.611, respectively). The peak value of troponin T also correlated positively with the peak values of noradrenaline and adrenaline (r=0.828 and r=0.792, respectively).
Conclusions These results suggest that the elevated activity of the sympathetic nervous system observed in the acute phase of SAH induced myocardial damage and contributed to the development of cardiac dysfunction.
Key Words: cardiovascular diseases catecholamines subarachnoid hemorrhage sympathetic nervous system ventricular dysfunction dogs
| Introduction |
|---|
|
|
|---|
In the present study we used a unique animal model that simulated the rupture of a cerebral aneurysm and subsequent SAH to examine the existence of a correlation between sympathetic activation and myocardial damage immediately after SAH.
| Materials and Methods |
|---|
|
|
|---|
A 6F plus sheath introducer (501-606U, Cordis) was placed in the abdominal aorta through the left femoral artery to measure aortic blood pressure. A 5.5F Swan-Ganz catheter (93-631H-5.5F, Baxter) was inserted into the pulmonary artery through the left femoral vein to measure pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCP), central venous pressure (CVP), and cardiac output (CO). Intracranial pressure (ICP) was continuously monitored throughout the experiment with a Camino pressure-monitoring catheter (model 110-4G, Camino Laboratory).
A pericardial cradle was placed after a left thoracotomy was performed at the fifth intercostal space.11 A pair of ultrasonic crystal transducers (45295, NEC Sanei) were fixed on the anterolateral wall of the left ventricle at a distance of 15 mm to assess left ventricular wall motion (LVWM). Left ventricular pressure (LVP) was measured with the use of a tip manometer (SPR-524, Miller Instruments) that was inserted into the left ventricle through an 18-gauge catheter (Instyle 3878188, Becton Dickinson Vascular Access) puncturing the LV free wall. The peak rate of LVP increase (peak positive dP/dt), as a parameter of isovolemic contractility, and the peak rate of LVP decline (peak negative dP/dt), as a parameter of myocardial relaxation, were measured by analog differentiation of the LVP.12 All pressures were recorded with the use of calibrated pressure transducers connected to an appropriate amplification system. The catheter (5.0F IC COBRA A, Toray Medical) for blood collection was inserted into the coronary sinus through the left external jugular vein.
Procedure of Experimental SAH
An angiocatheter (Graid Cath II, RF-WL 14010, Termo) was inserted into the right vertebral artery via the right femoral artery. After the circle of Willis was identified by angiography, a microcatheter (RF-SP 26137, Termo) was inserted into the basilar artery through the angiocatheter to provoke SAH (Figure 1a and 1b). We used the guidewire of the microcatheter to pierce the top of the basilar artery and cause SAH. Three thousand units of heparin were injected intravenously before this manipulation to promote bleeding from the perforated site and to prevent complications due to thromboembolism. After the experiment, we confirmed the extravasation of contrast medium indicating SAH by repeated cerebral angiography (Figure 1c). Figure 2a and 2b show the extensive SAH macroscopically observed in the brain resected from an experimental dog.
|
|
Experimental Protocol
The animals were stabilized for 60 minutes before SAH was provoked. Blood was collected from the coronary sinus, and hemodynamic parameters were assessed before (0 minute) and 5, 15, 30, 60, 120, and 180 minutes after SAH. ECG, heart rate (HR), aortic blood pressure, PAP, PCP, CVP, LVP, peak positive dP/dt, peak negative dP/dt, LVWM, and CO were recorded simultaneously at each time point. LVWM was determined by the oscillation of signals obtained from the ultrasonic crystal transducers. LVWM and CO were expressed as percentages of their respective baseline value at 0 minute.
Evaluation of Sympathetic Nervous Activity
As indicators of the activities of the central and peripheral noradrenergic nervous systems, we measured the plasma concentrations of noradrenaline, adrenaline, and 3-methoxy-4-hydroxy-phenylethylene glycol (MHPG), which is a metabolite of noradrenaline derived from the central noradrenergic nervous system.13 Blood samples taken from the coronary sinus were collected into Vacutainer tubes containing EDTA-2Na and placed in ice. After the samples were immediately centrifuged at 4°C for 5 minutes, the plasma was stored at -20°C until their analysis. Plasma concentrations of noradrenaline and adrenaline were measured by high-performance liquid chromatography (HPLC). The plasma concentration of MHPG was determined according to the method of Semba et al,14 ie, the samples were subjected to HPLC after proteins were denatured with 10% ZnSO4 and 1N NaOH.14
Evaluation of Myocardial Damage
The concentrations of creatine kinaseMB (CK-MB), troponin T, and myosin light chain in coronary sinus blood were measured as parameters of myocardial damage. To determine serum CK-MB, sera were subjected to chemiluminescent immunoassay with the use of antiCK-MB monoclonal antibody (Chemilumi ACS-CK-MB, Bayer Diagnostics). Serum troponin T was measured with a commercially available assay kit (Elecsys Troponin T III STAT, Roche Diagnostics) to detect the immunocomplex of biotinylated antitroponin T enzyme marker antibody. Serum myosin light chain was measured by the radioimmunoassay fixation method (Myosin L.I. Kit Yamasa, Yamasa Ltd).
Statistical Analysis
All data are expressed as mean±SD. ANOVA was used for statistical comparison between the values obtained after SAH and the baseline value for each parameter. Differences with a P value of <0.05 were considered statistically significant.
| Results |
|---|
|
|
|---|
|
Figure 4 demonstrates the changes in plasma concentrations of noradrenaline, adrenaline, and MHPG after SAH. Noradrenaline and adrenaline increased significantly from 120±70 and 130±70 pg/mL at 0 minute to 1700±1200 and 5600±3500 pg/mL at 5 minutes (P<0.01 and P<0.01), respectively, and returned to baseline values 30 minutes after SAH. MHPG increased significantly from 1.3±0.5 ng/mL at 0 minute to 3.2±1.2 ng/mL at 15 minutes (P<0.01) and returned to the baseline value 30 minutes after SAH.
|
Hemodynamic changes after SAH are shown in Figures 5 and 6. HR was 140±20 bpm at 0 minute and significantly decreased by 15% to 20% >15 minutes after SAH (P<0.05 or P<0.01). Aortic blood pressure (systolic/diastolic pressure) increased significantly from 160±20/110±20 mm Hg at 0 minute to 260±60/170±30 mm Hg at 5 minutes (P<0.001) and then decreased significantly to values 40% to 50% of baseline values >30 minutes after SAH (P<0.001). PAP also increased significantly from 23±7/12±3 mm Hg at 0 minute to 41±18/24±13 mm Hg at 5 minutes (P<0.001); the systolic PAP decreased significantly to values 30% to 40% of baseline value >30 minutes after SAH (P<0.05). PCP and CVP increased significantly from 8±3 and 3±2 mm Hg at 0 minute to 20±10 and 7±3 mm Hg at 5 minutes (P<0.001 and P<0.001), respectively; they returned to baseline values >30 minutes after SAH. Peak positive and negative dP/dt increased significantly from 3300±700 and 3100±600 mm Hg/s at 0 minute to 7600±1600 and 4700± 1200 mm Hg/s at 5 minutes (P<0.001 and P<0.001), respectively; they decreased significantly to values 50% to 60% of the baseline values >30 minutes after SAH (P<0.01 or P<0.001). Both LVWM and CO increased significantly by 30% to 40% of baseline values at 5 minutes (P<0.001 and P<0.001); they decreased significantly by 30% to 50% of their baseline values >30 minutes after SAH (P<0.01 or P<0.001).
|
|
Figure 7 shows the plasma concentrations of CK-MB, troponin T, and myosin light chain before and after SAH. CK-MB increased significantly from 6.2±2.0 ng/mL at 0 minute to 13.8±5.6 ng/mL at 5 minutes (P<0.05) and continued to increase gradually until 180 minutes after SAH. Troponin T also increased significantly from 0.28±0.15 ng/mL at 0 minute to 1.1±0.9 ng/mL at 15 minutes (P<0.01) and reached its peak value of 2.5±1.6 ng/mL at 120 minutes (P<0.001). Myosin light chain showed a significant increase 60 minutes after SAH compared with its baseline value. Figure 8 illustrates the relationship between the peak value of CK-MB and peak values of catecholamines as well as between the peak value of troponin T and peak values of catecholamines. Both CK-MB and troponin T correlated positively with noradrenaline and adrenaline (CK-MB versus noradrenaline, r=0.730; CK-MB versus adrenaline, r=0.611; troponin T versus noradrenaline, r=0.828; troponin T versus adrenaline, r=0.792). However, there were no significant correlations between myosin light chain and catecholamines, nor did CK-MB, troponin T, and myosin light chain show a significant correlation with MHPG (data not shown).
|
|
| Discussion |
|---|
|
|
|---|
Recently, some clinical studies described left ventricular asynergy on an echocardiogram and left ventriculogram performed in patients with SAH.5,2329 Furthermore, it was reported that myocardial necrosis occurred in these patients, as evidenced by elevated serum concentrations of CK-MB, troponin T, or myosin light chain above the normal values within 2 to 3 days after the onset of SAH as well as the contraction band, myocardial fragmentation, and focal myocytolysis observed in the myocardium at autopsy.9,3032 We investigated the pathogenesis of cardiopulmonary complications on the basis of the clinical observation of 717 cases in the acute phase of SAH. There was transient left ventricular asynergy in 9.6% (
) of the cases, which consisted of mechanical heart failure and myocardial necrosis.33 One of the reasons for the occurrence of myocardial damage after SAH is the intense activation of the sympathetic nervous system, characterized by massive secretion of catecholamines from the terminals of sympathetic nerves into the tissue. Matsuyama et al33 showed that plasma levels of noradrenaline and adrenaline were higher in SAH patients with left ventricular asynergy than in those without it. Moreover, myocytolysis has also been observed around the terminals of sympathetic nerves in the autopsied myocardium obtained from patients with SAH.34 These previously reported clinical studies have demonstrated in detail the clinical course of myocardial damage subsequent to SAH. However, its pathogenesis is still unclear because we cannot evaluate the state of the patients until they are admitted to the hospital.
Using our unique model, we demonstrated in the present study that plasma concentrations of catecholamines temporally rose 15- to 30-fold at 5 minutes after SAH compared with baseline values. The present study showed an extremely enhanced sympathetic activity and a massive release of catecholamines from the terminals of sympathetic nerves. It is suspected that only a part of the catecholamines secreted into the tissues from the sympathetic nerve terminals enters the systemic circulation; therefore, the concentration of catecholamines at tissue level would be more elevated. The high concentration of catecholamines in the myocardium would bring about a calcium overload of myocardial cells,35 which would primarily cause a reduction of myocardial contractility36 and would secondarily lead to an impairment of cardiac function due to the perfusion disturbance at the level of capillaries caused by an enhanced platelet aggregation.37 The main reason for the enhanced sympathetic activity is expected to be the sudden elevation of ICP. This phenomenon could be induced when massive bleeding into the subarachnoid space occurs in a short period or when the systemic blood pressure directly causes an elevation of ICP after the rupture of a cerebral artery. Neil-Dwyer et al10 demonstrated that the autopsied myocardium of patients with SAH who had been given
-blockers and ß-blockers had significantly less damage, such as focal necrosis and inflammatory cell infiltration. Thus, additional studies should be planned with the use of this animal model not only to clarify the mechanism underlying cardiac complications of SAH but also to develop a treatment based on the protective effect of sympathetic nervous blockade on the myocardium.
In conclusion, the data obtained from our novel animal model of SAH suggest that the elevated activities of the sympathetic nervous system immediately after the onset of SAH induced myocardial damage, including dysfunction and necrosis.
| Acknowledgments |
|---|
Received August 24, 2001; revision received January 4, 2002; accepted January 24, 2002.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
S. Laowattana, S. L. Zeger, J.A.C. Lima, S. N. Goodman, I. S. Wittstein, and S. M. Oppenheimer Left insular stroke is associated with adverse cardiac outcome Neurology, February 28, 2006; 66(4): 477 - 483. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Mazighi, J.-P. Saint Maurice, A. Rogopoulos, and E. Houdart Extracranial vertebral and carotid dissection occurring in the course of subarachnoid hemorrhage Neurology, November 8, 2005; 65(9): 1471 - 1473. [Abstract] [Full Text] [PDF] |
||||
![]() |
W J Schuiling, P J W Dennesen, J T. J Tans, L M Kingma, A Algra, and G J E Rinkel Troponin I in predicting cardiac or pulmonary complications and outcome in subarachnoid haemorrhage J. Neurol. Neurosurg. Psychiatry, November 1, 2005; 76(11): 1565 - 1569. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Schillinger Editorial Comment--Brain Natriuretic Peptide and Early Cardiac Dysfunction After Subarachnoid Hemorrhage Stroke, July 1, 2005; 36(7): 1570 - 1571. [Full Text] [PDF] |
||||
![]() |
D. S. Ditor, M. V. Kamath, M. J. MacDonald, J. Bugaresti, N. McCartney, and A. L. Hicks Effects of body weight-supported treadmill training on heart rate variability and blood pressure variability in individuals with spinal cord injury J Appl Physiol, April 1, 2005; 98(4): 1519 - 1525. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Homma and C. Grahame-Clarke Editorial Comment--Myocardial Damage in Patients With Subarachnoid Hemorrhage Stroke, February 1, 2004; 35(2): 552 - 553. [Full Text] [PDF] |
||||
![]() |
K. B. Wallace, E. Hausner, E. Herman, G. D. Holt, J. T. Macgregor, A. L. Metz, E. Murphy, I.Y. Rosenblum, F. D. Sistare, and M. J. York Serum Troponins as Biomarkers of Drug-Induced Cardiac Toxicity Toxicol Pathol, January 1, 2004; 32(1): 106 - 121. [PDF] |
||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Stroke Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2002 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |