A novel principle for assessment of stimulated fibrinolysis.

After venous occlusion (VO), D-dimer levels were measured by means of an ELISA technique, in citrated plasma clotted by thrombin and in serum from whole blood. D-dimer levels increased with duration of incubation (30 min to 24 hours). D-dimer values, both in clotted plasma and in serum (n = 12), incubated 4 hours at room temperature, correlated well with euglobulin clot lysis time (ECLT) (r = -0.85 and -0.89, respectively, p less than 0.002) and tissue plasminogen activator (t-PA) activity, (r = 0.82 and 0.83, respectively, p less than 0.002). D-dimer concentrations from plasma and serum (n = 25) were compared (r = 0.90, p less than 0.001). Healthy volunteers (n = 65) were tested to establish reference values in serum from post-occlusive whole blood samples incubated 4 hours prior to centrifugation. Finally, a patient group (n = 62) was examined. For the whole material (n = 152) such D-dimer concentrations correlated well with both ECLT (r = -0.85, p less than 0.001) and t-PA activity (r = 0.81, p less than 0.001). D-dimer levels in serum were determined by a latex agglutination test as well. These semi-quantitative values also correlated significantly with both ECLT (r = -0.86, p less than 0.001) and t-PA activity (r = 0.87, p less than 0.001). We conclude that measurement of D-dimer as described above, represents a simple and accurate method for assessment of global fibrinolytic activity following VO. The latex agglutination test is particularly suitable as a screening procedure.

Comparison of thrombin-antithrombin complex (TAT) levels and fibrinopeptide A following thrombin incubation of human plasma using hirudin as an inhibitor of TAT formation.

Following incubation of citrated plasma with human thrombin, the interaction of thrombin with antithrombin III was measured as thrombin-antithrombin complex (TAT) concentration. Comparison was made to thrombin activity on fibrinogen, assayed as fibrinopeptide A (FPA). Light scattering studies were included to evaluate polymerization of fibrin. Hirudin, at a final concentration of 100 U/ml, effectively inhibited TAT generation at final thrombin concentrations below 0.4 NIH U/ml. Hirudin by itself did not affect the TAT ELISA analysis. TAT and FPA values correlated closely (r = 0.83, p less than 0.001) and may equally well represent in vitro thrombin activity.

Can psychological traits predict the outcome of lumbar disc surgery when anamnestic and physiological risk factors are controlled for? Results of a prospective cohort study.

In a prospective study 122 patients with herniated lumbar disc pre-operatively completed psychological questionnaires. Surgical outcome was evaluated 12 months post-operatively mainly by a composite clinical overall score (COS), and by its separate elements. Anxiety (HAD-A scale) and psychosomatic symptoms (MSPQ) had predictive value: fewer symptoms favoured a satisfactory overall outcome, and vice versa. The HAD-A Scale had a predictive power of poor (ppp) and satisfactory (pps) outcome of 28 and 81%, respectively. Correspondingly, for the MSPQ, the ppp and pps were 42 and 85%. Anamnestic and biological variables (including fibrinolytic variables: ECLT and PAI-1) predicted 20% of the outcome. By adding all psychological variables the prediction increased only to 24%, but the HAD-A Scale and the MSPQ were still significant. The results suggest that in order to further improve prediction of outcome, future studies should combine biological variables sensitive to the mental state of the patient, with psychometric assessments.

Influence of fibrinolytic factors on scar formation after lumbar discectomy. A magnetic resonance imaging follow-up study with clinical correlation performed 7 years after surgery.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To assess the amount of scar tissue by viewing magnetic resonance images, and to evaluate the correlation between the amount of scar tissue and clinical outcome, surgical technique, and fibrinolytic factors. SUMMARY OF BACKGROUND DATA: The influence of fibrinolytic factors on magnetic resonance images has not been investigated previously. The relation between clinical outcome and findings on magnetic resonance imaging remains uncertain. METHODS: Magnetic resonance imaging at 0.5 Tesla was performed to produce sagittal and axial spin-echo T1-weighted images before and after contrast enhancement on 78 patients 7 years after traditional lumbar discectomy with partial or full laminectomy. Before surgery all patients had been tested for fibrinolytic factors. RESULTS: The overall clinical success rate of the surgery was 73%. No evidence of scar formation was seen in 19 patients, a small amount was seen in 36 patients, a moderate amount in 17 patients, and a large amount was observed in 6 patients. Ten patients who had undergone surgery at two disc levels and 18 who had been treated with full laminectomy exhibited more scar tissue than those patients who had undergone surgery on a single level (P = 0.033) and those who had undergone a partial laminectomy, respectively (P = 0.017). The amount of scar formation also was associated with a poor outcome (P = 0.017) and with low preoperative values of tissue plasminogen activator antigen (P = 0.003) and tissue plasminogen activity (P = 0.048) in samples collected after venous occlusion. The intensity of contrast enhancement, however, was not influenced by these or any other parameters. CONCLUSION: The amount of scar formation after lumbar discectomy seems to be related to the clinical outcome, the size of the surgical exposure, and some fibrinolytic factors.

Fibrinolytic activity as a predictor of the outcome of prolapsed intervertebral lumbar disc surgery with reference to background variables: results of a prospective cohort study.

In a prospective study 122 patients with a slipped lumbar disc and no previous surgery were preoperatively examined for fibrinolytic activity. Surgical results for these patients were evaluated 12 months postoperatively by clinical overall assessment. In a multiple linear regression analysis fibrinolytic variables, euglobulin clot lysis time and plasminogen activator inhibitor 1, were shown to have predictive value regarding outcome of surgery; that is, normal fibrinolytic activity favors a satisfactory outcome and vice versa. Background variables and lipid profile were also recorded preoperatively. Body mass index, gamma-glutamyl transpeptidase, triglycerides and smoking were of statistical significance in relation to euglobulin clot lysis time and plasminogen activator inhibitor 1. Postoperative fibrinolytic re-examination of 20 patients seem to confirm that patients at risk of surgical failure have a prolonged depression of fibrinolytic activity.

Seven-year clinical follow-up after lumbar disc surgery: results and predictors of outcome.

This study evaluates the 7-year outcome of lumbar disc surgery and the predictive value of pre- and perioperative risk factors. The 7-year follow-up rate of a sample of 122 patients was 93% (n = 114). Six per cent of the patients had undergone repeat surgery. Approximately 90% reported that they were satisfied with having undergone surgery. The clinical outcome was evaluated in 96 patients (54 men and 42 women) by means of patient-scores (VAS) of low back and leg pain, and a Clinical Overall Score (COS). In multivariate regression analyses, women were shown to have poorer outcome than men. Preoperative psychological distress and impaired fibrinolytic activity were predictors of poor 7-year outcome. Age, weight, smoking habits and physical fitness had no statistically significant prognostic value. Whether the patients were operated for one or two herniated discs, or whether surgery involved a full or partial laminectomy, did not influence the outcome significantly.

Background variables (medical history, anthropometric and biological factors) in relation to the outcome of lumbar disc surgery.

In a prospective cohort study 122 patients with herniated intervertebral lumbar disc and no previous low back surgery preoperatively were assessed regarding medical history, anthropometric and biological background variables. The outcome of surgery (traditional methods) was evaluated one year postoperatively, mainly using a composite Clinical Overall Score (COS), including pain intensity, physical signs, functional capacity and analgesics. Return to work was also assessed. In regression analyses, low body height, high values of weight and body mass index, as well as long duration of sickness absence were shown to be significantly related to a poor outcome, as evaluated by the COS. However, after controlling for modifying effects of previously determined predictive fibrinolytic and psychological variables, the background variables lost their significance. Female sex, low stature, long duration of sickness absence and physically strenuous work activities were statistically significantly related to lower frequencies of return to work.