Perioperative Renal Outcome in Cardiac Surgical Patients With Preoperative Renal Dysfunction: Aprotinin Versus Epsilon Aminocaproic Acid

Antifibrinolytics and cardiac surgery: The past, the present, and the future

Cardiac surgery is usually associated with significant blood loss, which often necessitates blood transfusion. In order to decrease the risks associated with the latter, pharmacological as well as nonpharmacological strategies have been used to reduce blood loss. Among the pharmacological approaches, antifibrinolytic drugs are the mainstay. Aprotinin, which was the first ubiquitously used drug, fell into disrepute only to re-emerge after much debate. The decline of aprotinin paved the way for the lysine analogs. However, we must be aware with the side effects of these drugs as well as the dose modification required in special situations. Nonsaccharide glycosaminoglycans have been under investigation to overcome the drawbacks of the lysine analogs. It remains to be seen whether these drugs can replace the traditional antifibrinolytics.

Use of Topical Tranexamic Acid or Aminocaproic Acid to Prevent Bleeding After Major Surgical Procedures

OBJECTIVE:

To evaluate the literature describing topical use of tranexamic acid or aminocaproic acid for prevention of postoperative bleeding after major surgical procedures.

DATA SOURCES:

Literature was retrieved through MEDLINE (1946-September 2011) and International Pharmaceutical Abstracts(1970-September 2011) using the terms tranexamic acid, aminocaproic acid, antifibrinolytic, topical, and surgical. In addition, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION:

All identified articles in English were evaluated. Clinical trials, case reports, and meta-analyses describing topical use of tranexamic acid or aminocaproic acid to prevent postoperative bleeding were included.

DATA SYNTHESIS:

A total of 16 publications in the setting of major surgical procedures were included; the majority of data were for tranexamic acid. For cardiac surgery, 4 trials used solutions containing tranexamic acid (1-2.5 g in 100-250 mL of 0.9% NaCl), and 1 trial assessed a solution containing aminocaproic acid (24 g in 250 mL of 0.9% NaCl). These solutions were poured into the chest cavity before sternotomy closure. For orthopedic procedures, all of the data were for topical irrigation solutions containing tranexamic acid (500 mg-3 g in 50-100 mL of 0.9% NaCl) or for intraarticular injections of tranexamic acid (250 mg to 2 g in 20-50 mL of 0.9% sodium chloride, with or without carbazochrome sodium sulfate). Overall, use of topical tranexamic acid or aminocaproic acid reduced postoperative blood loss; however, few studies reported a significant reduction in the number of packed red blood cell transfusions or units given, intensive care unit stay, or length of hospitalization.

CONCLUSIONS:

Topical application of tranexamic acid and aminocaproic acid to decrease postsurgical bleeding after major surgical procedures is a promising strategy. Further data are needed regarding the safety of this hemostatic approach.

Acute kidney injury following cardiac surgery: role of perioperative blood pressure control

BACKGROUND/AIMS

Patients who develop acute kidney injury (AKI) after cardiac surgery continue to have a high mortality rate. Although factors that predispose to postoperative renal dysfunction have been identified, this knowledge has not been associated with a substantial reduction in the incidence of this serious adverse event.

METHODS

This review uses the existing literature to explore the relationship between AKI and perioperative blood pressure (BP) control in cardiac surgery patients. The results of recent novel analyses are introduced, and the implications of these studies for the management of cardiac surgery patients in the perioperative period are discussed.

RESULTS

Preexisting isolated systolic hypertension and wide pulse pressure increase the risk of postoperative renal dysfunction in the cardiac surgery population. New data suggest that BP lability (i.e., BP excursions outside an acceptable physiologic range) during cardiac surgery may also be an important predictor of subsequent renal dysfunction.

CONCLUSION

Recently published data suggest that perioperative BP lability influences both the risk of postoperative renal dysfunction and 30-day mortality. Future studies will determine whether the use of agents that allow improved BP control within a desirable range will reduce the incidence of postoperative AKI in cardiac surgery patients.

Aprotinin and renal dysfunction

Aprotinin is a polypeptide serine protease inhibitor used to prevent bleeding and need for transfusions in patients having heart surgery. A recent analysis of an observational study data set suggested the use of aprotinin was associated with an increased risk of developing renal failure. The present article reviews the data from basic science studies in tissues, animals and man together with the data from observational studies and randomised controlled trials. The interpretation of the data is hampered owing to the use of different endpoints to describe mild/moderate renal impairment. Nonetheless, the evidence points to aprotinin use being associated with a transient small rise in plasma creatinine concentration in certain patients. There is no evidence for an increased risk of developing new renal failure requiring dialysis/renal replacement therapy.