Differences in Coagulation and Haemostatic Parameters in Normal Women of Childbearing Age from Different Ethnic Groups and Geographical Locations

Vascular complications and coagulation-related changes in the perioperative period in Japanese patients undergoing non-cardiac surgery

AIM

To properly assess the guidance for perioperative management, we undertook a clinical epidemiology study with the primary aim of evaluating the incidence of perioperative vascular complications and their associated factors in a cohort of Japanese patients who underwent non-cardiac surgery in a tertiary medical care center.

METHODS

This observational study comprised two parts. In the first part, thrombotic and bleeding events and their risk factors in the perioperative period were evaluated in a total of 2,654 consecutive patients. In the second part, perioperative changes in coagulation-related factors, including the thrombin-antithrombin complex(TAT) and platelet aggregation activity, were serially characterized in 82 individuals randomly chosen from the consecutive patients.

RESULTS

The incidence of perioperative vascular complications was as follows: 1.0% for major bleeding, 0.21% for stroke and 0.21% for venous thromboembolism. No episodes of symptomatic myocardial infarction were identified in the studied population. Perioperative changes in coagulation-related factors were found to be complex and correlated in the mixed direction of pro- and anticoagulation. The TAT values showed prolonged(across postoperative days 1-5) and prominent(>116% increase) perioperative activation of coagulation, whereas global coagulation parameters, such as the prothrombin time, showed a tendency of anticoagulation in the immediate postoperative period.

CONCLUSIONS

Our data confirm the relatively low incidence of perioperative vascular complications in the general Japanese non-cardiac surgical population. Given the delicate balance between thrombotic and bleeding events, it is important to comprehensively understand the associations between the patient's baseline risk factors and vascular complications for effective clinical management.

Ethnic variations in platelet aggregation-comparison between saudi arabs, westerners (europeans and americans), asians and africans

SUMMARY. Platelet aggregation responses to adenosine diphosphate, adrenaline, collagen, arachidonic acid and ristocetin were measured in healthy subjects, predominantly blood donors residing in Riyadh, the capital city of Saudi Arabia. They were divided according to ethnic origin into Saudi Arabs n = 517, Westerners (Europeans and Americans) n = 93, South East Asians (Koreans and Filipinos) n = 154, and West Africans n = 77. Significant differences in the aggregation responses were found between the four ethnic groups. Saudi Arabs and Westerners showed better aggregation responses to ADP than Asians and Africans. Aggregability in response to collagen was greater in Saudis and Africans than in Westerners and Asians. There was remarkable inhibition of adrenaline induced-aggregation in Asians while other populations produced comparable results. Inhibited responses to arachidonic acid were most prevalent among Westerners and to a lesser extent in Asians than in Saudis and Africans. Ristocetin-induced aggregation was significantly inhibited in Africans and less so in Asians and Arabs and most pronounced in Westerners. These variations in platelet aggregability, which could not be related to blood group distribution, smoking habits, income, physical parameters of height and weight may be due to genetic and dietary factors. These ethnic differences should be taken into account when assessing aggregation responses in patients.

Coagulation effects of oral contraception

In Europe and North America, estrogen/progestogen oral contraception has been associated with an increase in venous thromboembolism, myocardial infarction, and stroke. These hazards are found mainly in smokers and in women over the age of 35. Venous thromboembolism appears to correlate with the estrogen dosage, and the arterial complications with both the estrogen and progestogen components. Blood coagulation and vascular thrombosis are intimately related. Estrogen/progestogen oral contraception affects blood clotting by increasing plasma fibrinogen and the activity of coagulation factors, especially factors VII and X; antithrombin III, the inhibitor of coagulation, is usually decreased. Platelet activity is also enhanced with acceleration of aggregation. These changes create a state of hypercoagulability that, to a large extent, appears to be counterbalanced by increased fibrinolytic activity. Studies of the oral contraceptives in current use show that the coagulation effects depend on the dosage of estrogen and the type of progestogen used in combination. Current research is aimed at finding the estrogen/progestogen formulations that induce the least changes in the coagulation system and other physiologic processes. In this respect, the new low-dose formulations are a major step forward and should reduce the risk of vascular thrombotic complications.