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Platelet adhesiveness in temporary residents of high altitude
0049-3848/81/060685-03$02.00/O 'JXRONBOSISRESEARCB 21; 685-687, 1981 Copyright (c) 1981 Pergsmon Press Ltd Printed in the USA. All rights reserved.
BRIEF
PLATELET
COMMUNICATION
ADHESIVENESS
IN TEMPORARY
Subhash Department
RESIDENTS
OF HIGH
ALTITUDE
C. SharA
of Pathology, Military Jabalpur, India- 482001
Hospital
(Received 9.2.1981; in revised form 24.2.1981. Accepted by Editor A.L. Bloom)
INTRODUCTION Significant changes in hemostasis occur in lowlanders exposed to highaltitude (1-4). Earlier we noted a significant increase in platelet adhesiveness (PA) only in those lowlanders who became (5). The symptomatic when taken to 3658m by air for a short period pattern of PA in those who stay at mountains for longer periods is In the present study platelet adhesiveness was estimanot known. residents of high altitude. ted in 65 temporary A group of lowlanders were also studied for comparison. Extensive review of the literature does not reveal a similar study.
MATERIAL
AND
METHODS
Subjects were studied in two groups. Group A consisted of fifty normal healthy subjects 21-35 years of age. They were permanent residents of plains (Lowlanders) and had never been to altitude higher than 1000m. Group B comprised of sixty-five healthy subjects 21-36 years of age. All were permanent residents of plains and had temporarily come to high altitude. They had been staying at 3OOGm or more since arrival and each had completed a continuous stay at high altitude of variable period at the time of this study. Depending on the duration of continuous stay, they were divided in the following subgroups. Subgroup Bl - 15 subjects who had completed a continuous stay of 20-30 days at high altitude; subgroup who had been staying at such heights for 31-90 B2 - 19 individuals days; subgroup B3 - 23 subjects who had continuously stayed for 90180 days; and subgroup B4 -'8 subjects who had been staying at high altitude for 181-360 days. KEY
WORDS:
Platelet adhesiveness, Haemostasis
Pulmonary 685
edema,
Hypoxia,
and
vo1.21, No.6
PLATELET ADHESIVENESS-
686
Platelet adhesiveness (PA) was estimated by the method of Estham (6) using siliconized apparatus. The results by this method have been found to be reproducible and reliable in this laboratory. Keeping in mind that factors like diet, smoking, drug and exercise, etc may affect PA, the procedure was standardized as rigidly as was practicable. Symptoms were recorded on a chart and were assigned (5). arbitrary scores as described in detail elsewhere
RESULTS
AND
DISCUSSION
The values of PA and the results of statistical analysis obtained by the analysis of variance for multiple comparisons are given in the table. 21-30 days of Subgroup Bl, who had completed stay at high altitude, showed a significantly high PA (PL 0.001) as Though the values remained high compared to the lowlanders (A). even up to 180 days of stay, a gradual fall was evident in subThis study shows that stabilization in PA occurs groups B2 and B3. after 181 days of continuous exposure. The mean symptom score of 1.2 and 1.0 respectively. subgroups Bl, B2, B3 and B4 was 5.2, 3.3, This suggests that high PA is associated with more side effects of altitude exposure in lowlanders as seen by a fall in the mean symptom score with the fall in platelet adhesiveness in the various subgroups of group B.
TABLE Pattern
of Platelet
Adhesiveness
(Mean
+ S.D.)
A
Bl
B2
B3
B4
PA(%)
57.5 ~8.3
65.8 ~7.2
63.3 29.2
61.0 r-7.9
58.3 27.2
P value A vs
-
Group
f 0.001
f 0.01
L 0.05
NS
The exact etiopathogenesis of various ill effects of altitude exposure is not yet well understood. Recent work has drawn attention to the possible role of altered hemostasis in general and platelet behavior in particular as important contributory factors (3, 5). Significantly enhanced PA has been recorded only in those who become symptomatic when airlifted to high altitude. This leads us to believe that enhanced PA may have a possible role in the development Thrombi in the systemic of circulation in these of such ailments. conditions have been reported (7) and platelet hyper adhesiveness may be contributory. Our data suggests a sudden rise in the PA on ascent to high altitude which starts falling after 31 days and tends to stabilize around 181 days of continuous stay. A tendency towards fall in PA was observed with a fall in the symptom score suggesting that lowlanders at high altitude take a long time to acclimatize to their new environments. This may partly explain why ill effects of such exposure occur even in those who have been staying at heights for long periods. However, further long term serial studies are needed to clearly evaluate and understand the importance of these findings.
vo1.21, No.6
687
PLATELET ADHESIVENESS
REFERENCES Hypoxia
and
blood
coagulation.
1.
KINGMA, H. and Aero Acts., 4,
2.
The coagulopathy GARVEY, M.B., DENNIS, L.H. and CONARD, M.F. of hypobaric induced polycythemia and its reversal with heparin. Clin Res., 16, 370-373, 1958.
3.
GRAY, BRYAN, A.C., FREEDMAN, M.H., HOUSTON, C.S., LEWIS, W.F., Effect of altitude exposure on MCFADDEN, D.M. and NOWELL, G. platelets. J. Apnl.Physiol., / 2, 648-659, 1975. D Platelet count on acute induction to high altiSHARMA, S.C. tude. Thrombos Haemostas. (Stuttg)., 9, 24, 1980.
4.
DELANGAN, C.D. 98-101, 1955.
Platelet S.C. and HOON, R.S. to high altitude. Thrombosis
adhesiveness on acute in, Res., l& 725-732, 1978.
5.
SHARMA, duction
6.
ESTHAM, R.D. Rapid J. Clin. Path., x,
7.
T.K. NAYAK, N.C., ROY, S. and NARAYANAN, Amer. J. Path., 3, of altitude sickness.
adhesive platelet 45-46, 1964.
count
in whole
Pathologic 381-391,
blood.
features 1964.
BRIEF
PLATELET
COMMUNICATION
ADHESIVENESS
IN TEMPORARY
Subhash Department
RESIDENTS
OF HIGH
ALTITUDE
C. SharA
of Pathology, Military Jabalpur, India- 482001
Hospital
(Received 9.2.1981; in revised form 24.2.1981. Accepted by Editor A.L. Bloom)
INTRODUCTION Significant changes in hemostasis occur in lowlanders exposed to highaltitude (1-4). Earlier we noted a significant increase in platelet adhesiveness (PA) only in those lowlanders who became (5). The symptomatic when taken to 3658m by air for a short period pattern of PA in those who stay at mountains for longer periods is In the present study platelet adhesiveness was estimanot known. residents of high altitude. ted in 65 temporary A group of lowlanders were also studied for comparison. Extensive review of the literature does not reveal a similar study.
MATERIAL
AND
METHODS
Subjects were studied in two groups. Group A consisted of fifty normal healthy subjects 21-35 years of age. They were permanent residents of plains (Lowlanders) and had never been to altitude higher than 1000m. Group B comprised of sixty-five healthy subjects 21-36 years of age. All were permanent residents of plains and had temporarily come to high altitude. They had been staying at 3OOGm or more since arrival and each had completed a continuous stay at high altitude of variable period at the time of this study. Depending on the duration of continuous stay, they were divided in the following subgroups. Subgroup Bl - 15 subjects who had completed a continuous stay of 20-30 days at high altitude; subgroup who had been staying at such heights for 31-90 B2 - 19 individuals days; subgroup B3 - 23 subjects who had continuously stayed for 90180 days; and subgroup B4 -'8 subjects who had been staying at high altitude for 181-360 days. KEY
WORDS:
Platelet adhesiveness, Haemostasis
Pulmonary 685
edema,
Hypoxia,
and
vo1.21, No.6
PLATELET ADHESIVENESS-
686
Platelet adhesiveness (PA) was estimated by the method of Estham (6) using siliconized apparatus. The results by this method have been found to be reproducible and reliable in this laboratory. Keeping in mind that factors like diet, smoking, drug and exercise, etc may affect PA, the procedure was standardized as rigidly as was practicable. Symptoms were recorded on a chart and were assigned (5). arbitrary scores as described in detail elsewhere
RESULTS
AND
DISCUSSION
The values of PA and the results of statistical analysis obtained by the analysis of variance for multiple comparisons are given in the table. 21-30 days of Subgroup Bl, who had completed stay at high altitude, showed a significantly high PA (PL 0.001) as Though the values remained high compared to the lowlanders (A). even up to 180 days of stay, a gradual fall was evident in subThis study shows that stabilization in PA occurs groups B2 and B3. after 181 days of continuous exposure. The mean symptom score of 1.2 and 1.0 respectively. subgroups Bl, B2, B3 and B4 was 5.2, 3.3, This suggests that high PA is associated with more side effects of altitude exposure in lowlanders as seen by a fall in the mean symptom score with the fall in platelet adhesiveness in the various subgroups of group B.
TABLE Pattern
of Platelet
Adhesiveness
(Mean
+ S.D.)
A
Bl
B2
B3
B4
PA(%)
57.5 ~8.3
65.8 ~7.2
63.3 29.2
61.0 r-7.9
58.3 27.2
P value A vs
-
Group
f 0.001
f 0.01
L 0.05
NS
The exact etiopathogenesis of various ill effects of altitude exposure is not yet well understood. Recent work has drawn attention to the possible role of altered hemostasis in general and platelet behavior in particular as important contributory factors (3, 5). Significantly enhanced PA has been recorded only in those who become symptomatic when airlifted to high altitude. This leads us to believe that enhanced PA may have a possible role in the development Thrombi in the systemic of circulation in these of such ailments. conditions have been reported (7) and platelet hyper adhesiveness may be contributory. Our data suggests a sudden rise in the PA on ascent to high altitude which starts falling after 31 days and tends to stabilize around 181 days of continuous stay. A tendency towards fall in PA was observed with a fall in the symptom score suggesting that lowlanders at high altitude take a long time to acclimatize to their new environments. This may partly explain why ill effects of such exposure occur even in those who have been staying at heights for long periods. However, further long term serial studies are needed to clearly evaluate and understand the importance of these findings.
vo1.21, No.6
687
PLATELET ADHESIVENESS
REFERENCES Hypoxia
and
blood
coagulation.
1.
KINGMA, H. and Aero Acts., 4,
2.
The coagulopathy GARVEY, M.B., DENNIS, L.H. and CONARD, M.F. of hypobaric induced polycythemia and its reversal with heparin. Clin Res., 16, 370-373, 1958.
3.
GRAY, BRYAN, A.C., FREEDMAN, M.H., HOUSTON, C.S., LEWIS, W.F., Effect of altitude exposure on MCFADDEN, D.M. and NOWELL, G. platelets. J. Apnl.Physiol., / 2, 648-659, 1975. D Platelet count on acute induction to high altiSHARMA, S.C. tude. Thrombos Haemostas. (Stuttg)., 9, 24, 1980.
4.
DELANGAN, C.D. 98-101, 1955.
Platelet S.C. and HOON, R.S. to high altitude. Thrombosis
adhesiveness on acute in, Res., l& 725-732, 1978.
5.
SHARMA, duction
6.
ESTHAM, R.D. Rapid J. Clin. Path., x,
7.
T.K. NAYAK, N.C., ROY, S. and NARAYANAN, Amer. J. Path., 3, of altitude sickness.
adhesive platelet 45-46, 1964.
count
in whole
Pathologic 381-391,
blood.
features 1964.