Background: Aprotinin, a hemostatic agent, regulates fibrinolysis, modulates the intrinsic coagulation pathway, stabilizes platelet function, and exhibits anti-inflammatory properties through inhibition of serine proteases, such as trypsin, plasmin, and kallikrein. Aprotinin has been used successfully for many years in cardiac operations, and there have been preliminary investigations of its use in hip replacement operations. The objectives of this multicenter, randomized, placebo-controlled, double-blind trial were to evaluate the efficacy and safety of aprotinin as a blood-sparing agent in patients undergoing an elective primary unilateral total hip replacement and to examine its effect on the prevalence of deep-vein thrombosis in this population.
Methods: Seventy-three patients received a placebo; seventy-six patients, a low dose of aprotinin (a load of 500,000 kallikrein inhibitor units [KIU]); seventy-five, a medium dose of aprotinin (a load of 1,000,000 KIU, with infusion of 250,000 KIU per hour); and seventy-seven patients, a high dose of aprotinin (a load of 2,000,000 KIU, with infusion of 500,000 KIU per hour). The end points for the determination of efficacy were transfusion requirements and blood loss. Patients received standard prophylaxis against deep-vein thrombosis and underwent compression ultrasonography with color Doppler imaging of the proximal and distal venous systems of both legs to evaluate for the presence of deep-vein thrombosis.
Results: Aprotinin reduced the percentages of patients who required any form of blood transfusion (47 percent of the patients managed with a placebo needed a transfusion compared with 28 percent of those managed with low-dose aprotinin [p = 0.02],27 percent of those managed with high-dose aprotinin [p = 0.008], and 40 percent of those managed with medium-dose aprotinin [p = 0.5]). Only 6 percent (twelve) of the 212 patients treated with aprotinin required allogeneic blood compared with 15 percent (ten) of the sixty-eight patients treated with the placebo (p = 0.03). Aprotinin decreased the estimated intraoperative blood loss (p = 0.02 for the low-dose group, p = 0.04 for the medium-dose group, and p = 0.1 for the high-dose group), the measured postoperative drainage volume (p = 0.4 for the low-dose group, p = 0.006 for the medium-dose group, and p = 0.000 for the high-dose group), and the mean reduction in the hemoglobin level on the second postoperative day (thirty-four grams per liter for the placebo group, twenty-eight grams per liter for the low-dose group [p = 0.000], twenty-six grams per liter for the medium-dose group [p = 0.000], and twenty-three grams per liter for the high-dose group [p = 0.0001). The rate of deep-vein thrombosis was similar for all groups.
Conclusions: We concluded that aprotinin is safe and effective for use as a hemostatic agent in primary unilateral total hip replacements. In patients who are at high risk of receiving allogeneic blood, use of aprotinin may be of particular clinical and economic benefit.