986

FIBRINOLYSIS AND MYOCARDIAL

INFARCTION

R. D. MANNP. HUME KENDALL

J. K. YOUNG.

Clinical Research Department,Pfizer Ltd., Sandwich, Kent,and Department of PhysicalMedicine, Guy’s Hospital,

London S.E.1.

SIR,-Dr. Chakrabarti and his colleagues (March 12) showthat many patients younger than 60 years of age, who have sur-vived myocardial infarction, have defective fibrinolytic activity.This difference from age-matched controls is absent in similarpatients of older age-groups. These observations were made bymeans of the Fearnley 1 2 dilute blood-clot lysis-time (B.L.T.)technique which principally depends upon plasminogen-activator activity as the inhibitory activity of blood is reducedor removed by dilution.3

By a method 4 estimating the inhibitory effect of plasma uponurokinase-activated fibrinolysis, we have found that in 12

patients with rheumatoid arthritis under the age of 60 years themean inhibitory lysis-time was 692±80 seconds, and in 8 suchpatients over the age of 60 years this value was 605 ± 60 secondsŃa difference of 87 seconds, which is significant (P=0-05).This result was obtained by duplicate observations, and wasconfirmed in 6 patients under 60 years of age and 7 from olderage-groups with a comparable degree of disease activity. Since

lysis-times were comparatively short, the significantly greaterinhibitory activity of the patients under 60 years of age repre-sents a substantial difference in plasma-inhibitor concentration,as shown by the assay system used.4 In a sex and age matchedcontrol series of non-rheumatoid arthritis patients, meaninhibitory activity did not differ significantly in subjects underand over 60 years of age.

In the 20 patients with rheumatoid arthritis the mean B.L.T.was 5-1±2-0 hours in the patients under 60 years of age and3-8 ± 1 1 hours in those of older age-groups. The mean plasma-fibrinogen level, as estimated by the method of Fearnley andBunim,5 was 552-5+115-0 mg. per 100 ml. in the 12 patientsunder 60 years of age and 488-8 ±94-3 mg. per 100 ml. in the 8patients over that age. In this small series, neither of thesedifferences reaches significant proportions.

Since our observations were made in patients who were notreceiving compounds known to affect fibrinolysis, we concludethat plasma activity inhibitory to fibrinolysis is significantlygreater in rheumatoid patients under 60 years of age than it is insimilar subjects of older age-groups.

SIR,-Dr. Rifkind and Dr. McNicol (April 16) suggest thatthe low fibrinolytic activity found in our patients with coronary-artery disease might reflect high lipid levels. We have, however,never found any correlation between blood fibrinolytic activityand serum-cholesterol levels; about plasma-triglyceride levelswe have no information, for we do not make this measurement.Serum-cholesterol levels were measured in our 86 patientswith coronary-artery disease, but since they were not neces-sarily done on the same day as were the dilute blood-clotlysis-times (B.L.T.S), we thought it wiser not to include themin our preliminary communication (March 12).We have since examined the data on 67 survivors of myo-

cardial infarction, aged 36-72, in whom B.L.T., euglobulinlysis-time (E.L.T.), and serum-cholesterol level (method ofZlatkis et al. 6), were estimated on a blood-sample obtained at10-11 A.M. Since this method of measuring cholesterol givesresults about 10% lower than do other methods, we havetaken 250 mg. per 100 ml. as the upper limit of normal. Wecan find no correlation between the serum-cholesterol levels

1. Fearnley, G. R., Balmfort, G., Fearnley, E. Clin. Sci. 1957, 16, 645.2. Fearnley, G. R., Chakrabarti, R. Lancet, 1962, ii, 128.3. Macfarlane, R. G. ibid. 1937, i, 10.4. Mann, R. D. J. clin. Path (in the press).5. Fearnley, G. R., Bunim, J. J. Lancet, 1951, ii, 1113.6. Zlatkis, A., Zak, B., Boyle, G. J. J. Lab. clin. Med. 1953, 41, 486.

of these patients and either B.L.T. or E.L.T., as the followingresults show:Serum-cholesterol Patients (no.) B.L. T.;" 7 hr. E.L.T.> 2 1/4 hr.

(mg. per 100 ml.)

> 250 24 6 (25%) 9 (38&deg;a)<250 43 14 (33%) 16 (37%)

Thus, taking a B.L.T. of ’?7 hours and an E.L.T. of :?21/4 hoursto signify low fibrinolytic activity (the B.L.T. :E.L.T. ratio isabout 3 1), low fibrinolytic activity, measured by either method,was as common among patients whose serum-cholesterol levelwas below 250 mg. per 100 ml. as among those in whom itwas above this figure. If the figure of 275 mg. per 100 ml.adopted by Dr. Rifkind and Dr. McNicol is used, much thesame results are obtained. When the patients aged below 60are considered separately the incidence of low fibrinolyticactivity is higher, as we reported in our preliminary com-munication, but the proportion with high and normal serum-cholesterol levels remains the same.

So far as cholesterol is concerned, therefore, we cannot agreethat the findings of Dr. Rifkind and Dr. McNicol in patientswith peripheral vascular disease, which may not be comparablewith coronary-artery disease, explain our findings in survivorsof myocardial infarction.

R. CHAKRABARTIG. R. FEARNLEYE. D. HOCKING.

Gloucestershire Royal Hospital,Gloucester.

Diary of the Week

MAY 1 TO 7

Monday, 2ndPOSTGRADUATE MEDICAL SCHOOL OF LONDON, Ducane Road, W.12

4 P.M. Dr. Samuel Oram: Angina Pectoris.

Tuesday, 3rdUNIVERSITY OF LONDON

5 P.M. (Royal Free Hospital School of Medicine, 8 Hunter Street, Bruns-wick Square, W.C.1) Prof. M. J. Blunt (University of New SouthWales): Structure and Function of Macroglia.

POSTGRADUATE MEDICAL SCHOOL OF LONDON2 P.M. Prof. H. 0. Thomas (University of Lagos): Odontogenic Fibroma

in Nigeria.6 P.M. Dr. G. E. Hale Enderby: Vascular Control-Deliberate Hypo-

tension.ROYAL ARMY MEDICAL COLLEGE, Millbank, London S.W.1

5 P.M. Mr. Geoffrey Bateman: Secretory Otitis.WESTMINSTER MEDICAL SCHOOL, Horseferry Road, S.W.1

5.15 P.M. Dr. J. A. Waddell: Flow in Collapsible Tubes or the " Water-fall" Phenomenon.

GENERAL INFIRMARY AT LEEDS, Great George Street, Leeds 15.15 P.M. Dr. L. A. Liversedge: Clinical Interpretation of Involuntary

Movements. (Sandoz Foundation lecture.)

Wednesday, 4thPOSTGRADUATE MEDICAL SCHOOL OF LONDON

2 P.M. Prof. R. R. Porter: Structure of Antibodies..INSTITUTE OF NEUROLOGY, National Hospital, Queen’s Square, London W.C.1

6 P.M. Prof. J. T. Eayrs: Influence of Thyroid on Developing NervousSystem.

7 P.M. Prof. J. P. M. Tizard: Cerebral Function in the Newborn.MANCHESTER MEDICAL SOCIETY

4.30 P.M. Prof. R. E. Steiner: Radiologist’s View of the Heart.

Thursday, 5thPOSTGRADUATE MEDICAL SCHOOL OF LONDON

3.30 P.M. Dr. R. I. S. Bayliss: Corticosteroids in Cardiovascular Disease.INSTITUTE OF LARYNGOLOGY

5.30 P.M. (Royal College of Surgeons of England, Lincoln’s Inn Fields,London W.C.2) Dr. T. V. L. Crichlow: Radiology of the Upper’Respiratory and Alimentary Tract.

ST. MARY’S HOSPITAL MEDICAL SCHOOL, Paddington, W.25 P.M. (Wright Fleming Institute) Mr. H. G. Dixon: Placental Anatomy.

WESTMINSTER MEDICAL SCHOOL5.15 P.M. Dr. Basil Morson: Diverticular Disease of the Colon.

HONYMAN GILLESPIE LECTURE5 P.M. (Royal Infirmary, Lauriston Place, Edinburgh 3) Dr. D. L.

Gardner: Problems and Perspectives in the Pathology of Rheuma-toid Arthritis.

UNIVERSITY OF ST. ANDREWS5 P.M. (Queen’s College, Dundee) Dr. D. G. Rushton: Drowning.

UNIVERSITY OF DUBLIN4.30 P.M. (School of Physic, Trinity College) Dr. Rosemary Biggs:

Advances in Blood-coagulation Theory and its Influence on theTreatment of Patients with Hxmorrhagic States. (John MalletPurser lecture.)

Friday, 6thROYAL COLLEGE OF SURGEONS OF EDINBURGH, Nicolson Street, Edinburgh 8

5 P.M. Prof. William Boyd (Toronto): Spontaneous Regression of Cancer.