Fibrinogen catabolism in patients with postoperative infectious complications

Fibrinogen metabolism in patients with spinal cord injury

BACKGROUND/OBJECTIVE

Deep venous thrombosis and pulmonary thromboembolism are common within weeks of spinal cord injury (SCI) but clinically uncommon in the chronically paralyzed. Fibrinogen half-life (FHL) and fibrin uptake of the legs (FUT), as indicators of an active thrombotic process, have been used to test this clinical impression.

METHODS

Data from the use of autologous preparations of radioiodinated fibrinogen to determine FHL and FUT in 17 men paralyzed at cervical (6), thoracic (10), and lumbar levels (1), at ASIA grades A (15) and C (2) in 1974 to 1976 were reviewed. Group A consisted of 12 subjects 29 +/- 8 years of age and paralyzed 1 week to 5 months (median, 1 month). Group B consisted of 5 subjects 46 +/- 17 years of age and paralyzed 24 to 96 months (median, 36 months). Group B subjects were older and paralyzed longer than Group A. Group C consisted of 4 able-bodied control subjects enrolled at the same time for FHL studies, and these subjects were 34 to 38 years of age.

RESULTS

FHL was 61 +/- 14 hours for all SCI subjects and 95 +/- 23 hours for Group C (P = 0.001). Group A FHL was 59 +/- 16 hours, and FUT was positive in 8 of 12 subjects. Group B FHL was 66 +/- 7 hours, and FUT was positive in 3 of 4 subjects (1 FUT not done; P = 0.30 and 1.0, respectively).

CONCLUSIONS

Fibrinogen metabolism was abnormal in patients with acute SCI at high risk for pulmonary thromboembolism (PE) but continued to be abnormal beyond the high risk period for PE, possibly because of the greater age of the patients in the long-term paralysis group.

Arterial graft maturation: The duration of thrombotic activity in Dacron aortobifemoral grafts measured by platelet and fibrinogen kinetics

Dacron is thrombogenic, hence small arterial grafts of this material frequently thrombose in the period prior to graft maturation. Anti-thrombotic therapy may therefore be indicated to preserve patency during this risk period. To evaluate the thrombogenicity of immature Dacron grafts, platelet and fibrinogen kinetics using 51Cr and 125I respectively were measured before operation and at 3, 6 and 9 months in 10 patients following aortobifemoral bypass and in 6 age-matched volunteers.

Platelet survival was reduced from 8.8±0.2 d before surgery to 7.4±0.24 d at 3 months. This was accompanied by an increase in platelet turnover from 39±2.4 × 109 l−1 d−1 to 46.9±2.9 × 109 l−1 d−1. Fibrinogen t1/2 fell from 3.72±0.13 d preoperatively to 3.36±0.11 d at 3 months, while fibrinogen fractional catabolic rate rose from 0.27±0.014 to 0.34±0.014. These changes were all significant (P < 0.01). Fibrinogen consumption had returned to normal by 6 months following surgery but platelet kinetics only equated to pre-operative levels at 9 months. We suggest that Dacron grafts are thrombogenically active for about 9 months. When anti-thrombotic therapy is indicated it should be continued throughout this period.

Postoperative deep venous thrombosis and infectious complications. A clinical study of patients undergoing colo-rectal surgery

The connection between deep venous thrombosis (DVT) and postoperative infectious complications (PIC) was studied in 170 patients (mean age 65.7 and 40--86 years) who had undergone open large bowel or rectal surgery. DVT was diagnosed by the 125I-fibrinogen method. DVT of the legs was found in 36 patients. In 58 patients with PIC the frequency of DVT in 41 patients receiving low-dose heparin was 29% and in 17 patients without heparin prophylaxis 71% (P less than 0.01). In 112 patients without infection the frequency of DVT in 98 patients receiving low-dose heparin was 12% and 14 patients without heparin prophylaxis 7%. The frequency of DVT was significantly lower in patients without infection compared to those with PIC (P less than 0.001). Serious DVTs were more common in patients with PIC compared to those without PIC (P less than 0.05). It is concluded that infections after open large bowel and rectal surgery is an important risk factor for the development of DVT. Low-dose heparin significantly reduces the frequency of DVT in infected patients.