For long-term central lines (CL), the lumen is the major source of central line-associated bloodstream infections (CLABSI). The current standard of care for maintaining catheter patency includes flushing the CL with saline or heparin. Neither agent has any antimicrobial activity. Furthermore, heparin may enhance staphylococcal biofilm formation. We evaluated the safety and efficacy of a novel nonantibiotic catheter lock solution for the prevention of CLABSI. Between November 2015 and February 2016, we enrolled 60 patients with hematologic malignancies who had peripherally inserted central catheters (PICC) to receive the study lock solution. The study lock consisted of 15 or 30 g/ml of nitroglycerin in combination with 4% sodium citrate and 22% ethanol. Each lumen was locked for at least 2 h once daily prior to being flushed. After enrollment of 10 patients at the lower nitroglycerin dose without evidence of toxicity, the dose was escalated to the higher dose (30 g/ml). There were no serious related adverse events or episodes of hypotension with lock administration. Two patients experienced mild transient adverse events (one headache and one rash) possibly related to the lock and that resolved without residual effect. The CLABSI rate was 0 on lock days versus 1.6/1,000 catheter days (CD) off lock prophylaxis, compared with a rate of 1.9/1,000 CD at the institution in the same patient population. In conclusion, the nitroglycerin-based lock prophylaxis is safe and well tolerated. It may prevent CLABSI when given daily to cancer patients. Large, prospective, randomized clinical trials are needed to validate these findings. (This study has been registered at ClinicalTrials.gov under identifier NCT02577718.) KEYWORDS nitroglycerin, catheter, lock solution, central venous catheter, infections, cancer patients C entral venous catheters (CVC) are imperative for the treatment and management of cancer patients, particularly those with hematological malignancies who require a long-term access for the administration of chemotherapy, antibiotics, blood products, and fluids as well as for frequent blood draws. However, these lifelines are the leading source of bloodstream infections, causing at least 400,000 episodes of bloodstream infections yearly in cancer patients (1) and contributing to up to 62% of the bloodstream infections in patients with long-term CVC (2, 3). These catheter-associated infections constitute a major public health challenge, with an estimated mortality rate of 10 to 25% (4) and estimated cost of $45,000 per episode (5).
