The aim of this study is to determine the predictive value of urinary
thromboxane A2 metabolites in early diagnosis of ME (Acute
Myocardial Infarction) and to compare its sensitivity and specificity with
other measures used to diagnose AMI as ECG (Electrocardiogram)
CKME (creatinine kinase-MB ) , LDH (lactate dehydrogenase) , and
myoglobin.
The present work was performed on 52 individuals . They were
divided into 3 groups ; group 1(30 patients suffering from AMI) , group
(12 patients suffering from unstable angina) , and group III (10 healthy
individuals as a control group). Single urine sample was obtained from
every patient as well as control subjects 6 hours from the onset of chest
pain for quantitative estimation of 1-2,3 dinor-TXB2 in urine. Two blood
samples were obtained from every patient and control subjects , one
within 6 hours after the onset of chest pain for estimation of serum
myoglobin and CICMB. The second blood sample was obtained 24 hours
after the onset of chest pain for estimation of serum levels of LDH to
confirm the diagnosis. ECG was performed for all patients and control
subjects 6 and 24 hours after the onset of chest pain.
It was found that urinary 1-2,3 dinor-TXB2 , within 6 hours from the
onset of chest pain, was elevated in all AMI patients except one (96.7%).
In unstable angina group, it is elevated in all patients except two with
levels much less than those of AMI group. All control subjects had
normal urinary 1-2,3 dinor-TXB2. A positive interrelationship was found
between 1-2,3 dinor-TXB2 , CICMB , and myoglobin measured within 6
hours after the onset of chest pain.
In diagnosing AM1, urinary 1-2,3 dinor-TXB2 showed sensitivity of
96.7% , specificity of 91.7% ,positive predictive value (PPV) of 96.7% ,
negative predictive value (NPP) of 91.7%, and accuracy of 95.2%. this
very high degree of sensitivity and specificity indicated that urinary 1-2,3
dinor-TXB2 measurement is a sensitive and specific method for early
diagnosis of AMI. It is also a very rapid test, cost effective , detected in
urine early in the course of AMI and is not affected by anti-platelet drugs
or muscular injury. Moreover , its sensitivity, specificity , PPV , NPP ,
and accuracy are higher than that of CICMB and myoglobin in early
diagnosis of AMI.
Serum myoglobin was found to be more sensitive than CKMB and
ECG in early diagnosis of AM!. However, ECG is more sensitive than
CKMB at this time. Also, ECG was found to be the most specific
procedure for early diagnosis of AMI. Accordingly , the measurement of
urinary 1-2,3 dinor-TXB2 and other serum cardiac markers (CKMB , LDH
, and myoglobin ) may lead to a more accurate and timely diagnosis of
AM!. |
