Propofol Could Provide Benefits in Open Heart Surgery

A new study suggests that the intravenous (IV) anesthetic propofol may offer an effective approach to protecting the heart from damage during open heart surgery, particularly amongst diabetics.

Researchers at the Vancouver Coastal Health Research Institute (VCHRI; Canada) and the University of British Columbia (UBC; Vancouver, Canada) conducted a randomized trial in 137 patients scheduled for open heart surgery employing normothermic cardiopulmonary bypass (CPB) and blood cardioplegia. Study participants were stratified by diabetic status and left ventricular ejection fraction (LEVF) and randomly assigned to receive either a highly controlled, increasing dose of propofol for a focused period of time during CPB, or an isoflurane preconditioning regime. The primary endpoint was the coronary sinus concentration of 15-F2t-isoprostane (isoP).

The results showed that the patients receiving propofol experienced a greater increase in isoP levels compared with those receiving isoflurane, but a decreased incidence of low cardiac output syndrome (LCOS). The incidence of LCOS was similar between both groups in participants without type 2 diabetes mellitus (DM2), but significantly decreased in the propofol DM2 subgroup compared with the isoflurane DM2 subgroup. Propofol was also associated with fewer heart failure events. The study was published on December 31, 2015, in the Canadian Journal of Anesthesia.

“This has been the operating paradigm for years; anesthesiologists are taking advantage of an antioxidant property of propofol to stop free radical insult, which ultimately is expected to translate into improved outcomes,” said lead author David Ansley, MD, of the VCHRI and the UBC department of anesthesiology, pharmacology, and therapeutics. “Quite paradoxically, based on our research we think the drug actually stimulates a process that is pro-oxidant, rather than antioxidant, and the cells in the heart are responding to these pro-oxidant activities.”

“Originally we thought we’re protecting the heart by soaking up free radicals, but the reality is that propofol and how we administer it is actually changing the biology of the heart to a more favorable profile that protects mitochondria, keeping cell tissue alive,” continued Dr. Ansley. “We’ve found a technique that doesn’t currently exist that we actually believe will be of true benefit to diabetes patients undergoing open heart surgery.”

Propofol, discovered in 1977, is a short-acting IV anesthetic that is used for initiation and maintenance of general anesthesia, sedation for mechanically ventilated adults, and procedural sedation. It is often referred to as “milk of amnesia” because of its milk-like appearance and lack of memory of events during administration. Common side effects include an irregular heart rate, low blood pressure, burning sensation at the site of injection, and apnea. Other serious side effects may include seizures, infections, addiction, and propofol infusion syndrome with long term use.

Related Links:
Vancouver Coastal Health Research Institute
University of British Columbia