Impact of Tranexamic Acid Use in Transfusion Rate in Patients With Complex Kidney Stone Undergoing Percutaneous Nephrolithotomy: Randomised, Double-blind, Placebo Controlled Trial

Introduction: Kidney stone is a high incidence and prevalent disease affecting people around the world. Nearly 1 in 11 individuals in the United States will be affected at some point in their lives. Furthermore, stones are likely to recur with at least 50% of individuals experiencing another stone within 10 years of the first occurrence. Moreover, the disease mainly affects the economically active segment of the population with special social and economic implications in health.

Approximately 85% of stones are composed predominantly by calcium compounds and about 7% are attributed to urinary tract infections, named struvite stones, that usually develop as jagged structures called "staghorns" and can grow to be quite large, therefore becoming complex kidney stone. However, in HCFMUSP, as a Brazilian national reference center in urolithiasis treatment, this complex stones represents about 30 percent of all renal lithiasis treated.

This complex stones require individualized and specialized treatment, with percutaneous nephrolithotomy (PCNL) as the standard of care, with advantages of higher stone clearance and cost-effectiveness when compared with other treatment alternatives.

However, PCNL is associated with significant morbidity such as fever, urinary infections, septicemia and bleeding that may require blood transfusion. Of these complications bleeding is the most unpredictable and dreaded, and can lead to significant morbidity, beyond the potential risks of blood transfusions by itself.

In this way antifibrinolytic drugs, such as tranexamic acid, have been shown to reduce blood loss in a variety of surgical procedures, blood transfusion rate, morbidity and mortality related to bleeding.