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| Year : 1985 | Volume
: 31
| Issue : 4 | Page : 196-8 |
Comparison of two prognostic indices in acute myocardial infarction.
Saxena KK, Gupta BB, Gopal RR, Srivastava SS, Kulshrestha VK, Prasad DN
How to cite this article:
Saxena K K, Gupta B B, Gopal R R, Srivastava S S, Kulshrestha V K, Prasad D N. Comparison of two prognostic indices in acute myocardial infarction. J Postgrad Med 1985;31:196 |
How to cite this URL:
Saxena K K, Gupta B B, Gopal R R, Srivastava S S, Kulshrestha V K, Prasad D N. Comparison of two prognostic indices in acute myocardial infarction. J Postgrad Med [serial online] 1985 [cited 2023 Sep 21];31:196. Available from: https://www.jpgmonline.com/text.asp?1985/31/4/196/5383 |
The early mortality in patients with acute myocardial infarction (AMI) is mainly the result of massive myocardial damage.[1],[3],[6]Several indices have been used to assess the prognosis of such patients.[1],[2],[4],[7],[8],[10]
Mishra et al[5]tried to compare the relative accuracy of some coronary prognostic indices in Indian patients, but no concrete conclusion could be arrived at. The present authors, therefore, attempted to compare the recently devised Chapman-Gray coronary prognostic index[3] with the more widely used Norris Index[6]by computing both the indices in patients who had suffered acute myocardial infarction and were admitted into an intensive coronary care unit.
This is a study of sixty patients, 54 males and 6 females, in the age group of 35-75 years, with acute myocardial infarction who were admitted to the intensive coronary care unit of the S.V.B.P. Hospital, Meerut and had survived the first 24 hours after the onset of illness. On admission, a detailed clinical history of each patient was recorded, particular importance being attached to the age and the previous history of ischaemic heart disease. A detailed physical examination was performed and blood pressure, presence of shock, cardiac failure and other complications were noted. Electrocardiogram was recorded on admission and on the following 3-5 days to confirm the diagnosis and to find out the extent and site of infarction, arrhythmias or conduction defects. A portable chest radiograph was taken as soon as possible after admission, with the patient sitting or in a supine posture. Aspartate aminotransferase (SGOT)[9]was estimated at 24 hours after the onset of symptoms and on 2nd, 3rd and 4th day after admission; it was also repeated whenever chest pain recurred.
Cardiogenic shock was diagnosed if hypotension (systolic blood pressure 80 mm Hg), cyanosis and cold extremities persisted for more than 30 minutes after the relief of pain and administration of oxygen. Oliguria was diagnosed if the 24 hours urine output was < 500 MI.
Each patient's prognostic index was calculated both by the method of Norris et al[6]and by Chapman and Gray[3]score and the two indices were compared as regards the prediction of mortality. As the mortality was high in patients with Chapman and Gray[3]index of 7 or more and Norris index of 8 or more, these were taken as cut off points for the respective indices. Next, each of these 60 patients was categorised as having good or bad prognosis (good prognosis meaning survival and bad prognosis meaning death while in ICCU) on the basis of these cut off points for each of the two indices. This prediction of the outcome was then compared with the actual outcome of the patient. If the two tallied, it was called correct prediction and if they did not tally, it was called wrong prediction. The results were analysed by using McNemar's chi square test. Similar analysis was done by changing the cut off points to 70 and above for Chapman and Gray index and 12 and above for Norris index.
[Table 1]shows the mortality for different values of the two indices. The mortality rose alongwith the score in case of both the indices. The Table shows that the mortality was 10/28 in patients with Chapman-Gray index > 7 whereas it was 2/32 in patients with Chapman and Gray score < 6; similarly the mortality was 8/22 in patients with Norris index > 8 whereas it was 4/38 in those with Norris index < 7.9.
[Table 2]shows the results of prediction after taking cut-off points of 7 in Chapman and Gray index and 8 in Norris index. It can be seen from the table using McNemar's chi square test that the difference between predictive ability of the two tests is not statistically significant.
.Similar results were obtained by changing the cut off points to 70 and above for Chapman and Gray index and 12 and above for Norris index.
This work suggests that there was no statistically significant difference between predictive ability of Chapman and Gray index and Norris index. Hence, the choice of the index will depend upon the convenience of its computation. As the Chapman and Gray index has a ready reckoner and is more objective, than the Norris index, it would be preferable to use Chapman and Gray index than Norris index.
| 1. | Chapman, B. L.: Prognostic factors in acute myocardial infarction treated in a coronary care unit. Austral. New Zealand J. Med., 1: 53-62, 1971.  |
| 2. | Chapman, B. L.: Relation of cardiac complications to SCOT level in acute myocardial infarction. Brit. Heart J., 34: 890-896, 1972. |
| 3. | Chapman, B. L. and Gray, C. H.: Prognostic index for myocardial infarction treated in a coronary care unit. Brit. Heart J., 35: 135-141, 1973. |
| 4. | Hughes, W. L., Kalbfleisch, J. M., Brandten, Jr. and Costiloe, J. P.: Myocardial infarction prognosis by discriminant analysis. Arch. Int. Med. Chicago, 111: 338-345, 1963. |
| 5. | Mishra, S. J., Sharma, S. C., Bandi, S. C., Periwal, P. K., Amin, B. M., Shah, N. J. and Pinto, I. J.,. An evaluation of the prognostic indices in acute myocardial infarction. J. Postgrad. Med., 23: 101-105, 1977. |
| 6. | Norris, R. M., Brandt, P.W.T., Caughey, D. E., Lee, A. J. and Scott, P. J.: A new coronary prognostic index. Lancet, I: 274-278, 1969. |
| 7. | Norris, R. M., Brandt, P. W. T. and Lee, A. J.: Mortality in a coronarycare unit analysed by a new coronary prognostic index. Lancet, I: 278-281, 1969. |
| 8. | Peel, A. A., Semple, T., Wang, I., Lancaster, W. M. and Dall, J. L.: A coronary prognostic index for grading the severity of infarction. Brit. Heart J., 24: 745-760, 1962. |
| 9. | Reitman, S. and Frankel, S.: A colorimetric method for determination of serum glutamic oxaloacetic and glutamic pyruvic transaminase. Amer. J. Clin. Path., 28: 56-63, 1957. |
| 10. | Schnur, S.: Mortality rates in acute myocardial infarction. II. A proposed method for measuring quantitatively severity of illness on admission to the hospital. Ann. Int. Med., 39: 1018-1025, 1953. |
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