Study design: Randomized, investigator-driven, open-label study comparing two different hydration strategies.
Setting: Multicenter trial in Italy involving patients with chronic kidney disease scheduled for angiography who met the inclusion and exclusion criteria for high risk of developing CI-AKI.
Synopsis: The study included 292 patients randomized to receive sodium bicarbonate solution (control group) versus hydration with saline controlled by the RenalGuard system with furosemide. Both groups received NAC, though at different doses and routes of administration. CI-AKI occurred in 20.5% (30 of 146) in the control group versus 11% (16 of 146) in the RenalGuard group.
Bottom line: Controlled forced diuresis to achieve high urine flow rate is more effective than conventional hydration with sodium bicarbonate solution in high-risk patients for preventing CI-AKI. Larger studies are needed to confirm and define the role of the RenalGuard system.
Citation: Briguori C, Visconti G, Focaccio A, et al. Renal insufficiency after contrast media administration trial II (REMEDIAL II). Circulation. 2011;124:1260-1269.
Severe Asymptomatic Carotid Artery Stenosis Does Not Increase Stroke or Mortality Risks after CAB Surgery
Clinical question: What is the risk for stroke in patients with asymptomatic carotid artery stenosis (CAS) who are undergoing coronary artery bypass grafting (CABG)?
Background: Stroke occurs as a complication of CABG in approximately 2% of patients. The vast majority occur within the first 24 hours of surgery and are associated with a high mortality rate.
Study design: Retrospective cohort.
Setting: A single institution in Washington, D.C.
Synopsis: Data were collected on 878 consecutive patients who had undergone carotid ultrasound before CABG over a six-year period. Patients with severe CAS of >75% (n=117) were compared with those with <75% stenosis (n=761) to assess the rates of in-hospital stroke and mortality.
Patients with severe CAS had similar rates of stroke compared with those without severe CAS (3.4% vs. 3.6%). Additionally, there was no difference in the incidence of in-hospital complications or mortality between the two groups.
Bottom line: The cause of stroke after CABG is complex and multifactorial, but severe CAS alone appears to not be the biggest risk factor for stroke in patients undergoing CABG.
Citation: Mahmoudi M, Hill PC, Xue Z, et al. Patients with severe asymptomatic carotid artery stenosis do not have a higher risk of stroke and mortality after coronary artery bypass surgery. Stroke. 2011;42:2801-2805.
Cardiac Arrest Survivors Have Long-Term Memory Deficits
Clinical question: Are there any lasting cognitive deficits in patients surviving out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation (VF)?
Background: Although advances have been made in the rapid intervention of OHCAs, there are no population-based, age-adjusted studies of the cognitive and neurologic outcomes of long-term survivors when the “chain of survival” is used (rapid emergency services, bystander CPR, early defibrillation, and advanced care).
Study design: Prospective population-based, age-adjusted study.
Setting: Single hospital in Olmsted County, Minn.
Synopsis: Of 332 OHCA patients, 47 survivors were enrolled for neurologic and neuropsychological testing at least six months after a near-death experience (median time since arrest, 7.8 years). Neurologic examination did not reveal any focal deficits related to the event, but long-term survivors had lower scores on measures of long-term memory and learning efficiency (P=0.001). Nearly all survivors were functionally independent at the time of testing. Interestingly, there was no correlation between prolonged call-to-shock time and cognitive ability, suggesting that there is a possibility of positive neurologic outcomes with a call-to-shock time as late as 10 minutes in OHCA. Older age was also not identified as a negative prognostic factor.
A limitation of the study was the small sample size, though larger populations of survivors are difficult to find. The precise meaning of “cognitive impairment” was also controversial and should be better defined for any future studies.