Download Ihsan Husain Mohammed Ali

Role of Chromogranin a in The Assessment of Sympathetic Activity
in Acute Myocardial Infarction
A THESIS
SUBMITTED TO THE COUNCIL OF THE COLLEGE OF
MEDICINE
UNIVERSITY OF DUHOK IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE
OF MASTER OF SCIENCE
IN
MEDICAL PHYSIOLOGY
By
Ihsan Husain Mohammed Ali
B.V.M.
College of Veterinary Medicine
2003
Supervised by
Assistant Professor
Assistant Professor
Dr. Qasim H. Abdullah
1431 A.H.
Dr. Sabri K. Shaikhow
2710 K.
2010 A.D.
Abstract:
Background
Measurement of chromogranin A in plasma has been used for the diagnosis and
prognosis of many endocrine and neuroendocrine tumors that are associated with
increased catecholamines secretion (Marek, 2004). Little is known, however, about
the magnitude of increased sympathetic activity after acute MI. Investigating the
value of plasma chromogranin A as a quantitative measurement for this purpose
probably will be of clinical significance.
Objective:
To evaluate the sympathetic nervous system activity, and related factors in patients
with acute myocardial infarction by measuring plasma chromogrnin A.
Subjects and Methods
The study subjects included in this study were classified into two groups:
patients with acute myocardial infarction (n = 45) and a group of apparently
healthy subjects (n = 30). General information and history were completed, then
measurement of vital signs, serum electrolytes, glomerular filtration rate (GFR),
echocardiography parameters (ejection fraction and fractional shortening), plasma
concentration of chromogranin A and serum concentrations of cardiac biomarkers
(markers of myocardial injury) and uric acid were performed. In MI group, the
samples were obtained within 24 hours of the onset of symptoms.
Results
A significant increase in the mean plasma chromogranin A level was observed
in patients with acute myocardial infarction compared to the healthy subjects
(182.6 Vs 307.4 ng/ml, respectively. P < 0.001). This was associated with
significant increases in the serum levels of cardiac biomarkers (CK-MB and
troponin I) and hs-CRP.
Using receiver-operating characteristics (ROC) curve analysis, measurement of
plasma chromogranin A level turned out to be a valid test for evaluation of
sympathetic system activity with an area under the curve (AUC) of 0.817 (P <
0.001). The value of plasma chromogranin A level greater than or equal to
252.1ng/ml had an accuracy of 77.3 %, sensitivity of 64.4 % and 96.7 % specificity
for establishing increased sympathetic system activity in patients with acute MI.
In patients with acute MI, no significant correlation was observed between the
plasma chromogranin A level and the time of sampling after the onset of symptoms
(r = 0.056, P = 0.72). Moreover, patients with acute inferior wall MI showed no
appreciable difference in plasma chromogranin A level from patients with other
sites of myocardial wall infarction (308.1 Vs 306.8 ng/ml, respectively), associated
with no significant difference in the vital signs between these two subgroups.
Sympathetic system activity (represented by plasma chromogranin A level)
was significantly lower in MI patients who received morphine compared to those
with negative history of morphine administration (325.2 Vs 236 ng/ml,
respectively with P = 0.01). However, plasma chromogranin A level was not
influenced by gender, history of diabetes mellitus and smoking history.
Conclusions:
 These data indicate that AMI is associated with increased sympathetic
nervous system activity and measurement of plasma chromogranin A
levels can be used readily to assess the extent of this activity.
 The magnitude of increased sympathetic system activity is not different
in patients with acute inferior wall MI and patients with other sites of
myocardial wall infarction.
 Morphine administration modulates sympathetic system activity after
AMI.