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Activation of the fibrinolytic, coagulation and plasma kallikrein-kinin systems may be responsible for some of the coagulation disorders and inflammatory sequelae seen after extracorporeal circulation. The activation pattern of these systems was studied in 10 children undergoing open heart surgery with extracorporeal circulation. Blood samples were drawn serially before, during and up to 48 h after surgery. The heparin injection induced a significant elevation of plasmin (PL) (p < 0.05) which stayed elevated during extracorporeal circulation. Antiplasmin (AP) values were reduced at wound closure, while the levels were significantly elevated 48 h postoperatively (p < 0.05). alpha 2-antiplasmin-plasmin (APP) increased significantly perioperatively peaking 10 min after the initiation of cardiopulmonary bypass (p < 0.05). The coagulation markers thrombin-antithrombin (TAT) and the prothrombin fragment F1 & 2 increased significantly, peaking at wound closure and at termination of bypass respectively (p < 0.05). Plasma kallikrein (KK) values increased significantly with subsequent decreased levels of prekallikrein (PKK) and kallikrein inhibitor (KKI) after heparin injection. The KK level stayed elevated during cardiopulmonary bypass (CPB). The proenzyme functional inhibition index (PFI index), defined as the sum of deviations from the control values for proenzyme and functional inhibition values of the coagulation, fibrinolytic and plasma kallikrein-kinin systems, correlated significantly to the duration of cardiopulmonary bypass (p < 0.05). We conclude that open heart surgery in children activates the fibrinolytic, coagulation and plasma kallikrein-kinin systems.

C3 activation products, terminal complement complex (TCC), and cytokines including interleukins 6 and 2 (IL-6, IL-2) and tumour necrosis factor-alpha (TNF), and the soluble IL-2 and TNF receptors were determined serially during and up to 48 h after open heart surgery in children. Significant increases were noted in soluble TNF and IL-2 receptor levels postoperatively (p < 0.05). No significant increase over preoperative levels was seen in the cytokines, except for IL-6 which was significantly increased postoperatively (p < 0.01), reaching a maximum 2 h postoperatively. C3 activation products and TCC levels increased significantly after weaning from cardiopulmonary bypass (p < 0.05). The IL-6 response lagged behind the complement activation. We found a significant correlation between duration of cardiopulmonary bypass and IL-6 levels 48 h postoperatively (r = 0.852, p < 0.05). We conclude that the concentration of complement activation products, IL-6 and the soluble TNF and IL-2 receptors are significantly increased after open heart surgery in children. The cytokine receptor response probably reflects some sort of regulatory mechanism.

The reproducibility of physical capacity expressed as cumulative work (CW) and work pulse (WP) as well as haemodynamic response to maximal exercise was evaluated by two different principles for increasing work load during a maximal bicycle ergometer exercise test: (i) stepwise increment (SI) of 50 Watts (W) every fourth minute; (ii) continuous increment (CI) of 10 W at the end of every minute, both with a starting load of 50 W. Forty apparently healthy men aged 29-69 (mean 47) years performed two tests with a mean interval of 17 (3-43) days. Group A: 10 men who did SI twice; group B: 10 who repeated CI; group C: 10 men who performed SI and CI alternatively; group D: 10 men who did SI in the morning vs afternoon. Error % (percentage of the absolute difference of the mean of two values) was 3.9 for CW in group A vs 7.8 in group B (p less than 0.05). The error % of heart rates at submaximal work levels were lower with SI than CI. Mean CW in group C was 182.3 +/- 65.1 kJ for CI and 154.8 +/- 48.8 kJ for SI (p less than 0.01), whereas the mean exercise time was 1206 +/- 297 s and 1089 +/- 197 s respectively (p less than 0.01). Group D subjects achieved 142.7 +/- 49.4 kJ in the morning and 134.4 +/- 48.8 kJ in the afternoon (p less than 0.05). No significant differences were noted for WP in groups A-D. A better reproducibility for CW was found for SI, whereas both tests had similar reproducibility for heart rate and blood pressure response during maximal exercise.

In order to assess normal physical performance in women, a near-maximal ergometer bicycle test was performed in 95 healthy non-athletic women aged 24-65 years (mean 44 years). The starting load was 50 W and the load was increased by 50 W every 4 min until exhaustion. Physical performance was expressed as cumulative work in Watts (W). All subjects had normal two-dimensional, M-Mode and Doppler echocardiographic findings. Physical performance was similar in the age groups 24-29, 30-39 and 40-49 years. Mean cumulative work among subjects less than 50 years was 1208 (600-1800) W vs. 947 (500-1600) W (p less than 0.001) in those greater than or equal to 50 years. Physical performance was similar in the age groups 50-59 and 60-65 years (NS). An inverse correlation between maximal heart rate and age was found (r = 0.64, p less than 0.001). Systolic blood pressure increased more during exercise in the subjects greater than or equal to 50 years (p less than 0.001 vs. those aged less than 50 years). M-Mode echocardiographic measurements at rest were similar in all age groups. These findings may be related to reduction in beta-sympathetic stimulation during exercise in women greater than or equal to 50 years of age.