New data show that a more restrictive transfusion strategy during cardiac surgery is not inferior to a more liberal strategy for either death or major morbidities in moderate- to high-risk patients. Results of the Transfusion Requirements in Cardiac Surgery (TRiCS III) trial were announced Sunday during the first Late-Breaking Science session.
“Results from prior clinical trials have left us in a state of clinical equipoise,” said C. David Mazer, MD, professor of anesthesia and physiology at the University of Toronto, who presented the trial. “Anemia in cardiac surgery is independently associated with adverse outcomes and red blood cell transfusions are associated with increased mortality. We needed an answer.”
In the trial, researchers randomized 5,243 cardiac surgery patients at 74 sites across 19 countries to either a restrictive blood transfusion trigger of less than 7.5 g/L or a more liberal transfusion trigger of less than 9.5 g/L. The primary outcome was a composite of all-cause mortality, myocardial infarction, new renal failure with dialysis or stroke.
Analysis found a 1.1 percent risk-reduction favoring the restrictive transfusion trigger, showing that the lower trigger is not inferior to the higher trigger. Secondary outcomes were similarly noninferior for the restricted trigger arm.
The only significant difference between the two arms was an expected lower use of blood products in the restricted trigger arm. Mazer estimated the reduced blood use translates to savings of about $3 million across the study population.
Subgroup analysis showed a slight superiority for the restrictive trigger in patients older than 75. Mazer said the group re-analyzed the data to confirm the age-related benefit for restricting transfusion, but could not explain the finding.
Results from another late-breaking trial presented Sunday indicate that neither of two agents commonly used to prevent serious outcomes or acute kidney injury following angiography improved the primary or secondary outcomes.
Both results come from the Prevention of Serious Adverse Events Following Angiography (PRESERVE) trial.
“Earlier trials have been underpowered and provided divergent findings, but these results are very explicit: Oral NAC does not work and sodium bicarbonate works no better than isotonic saline,” said Steven Weisbord, MD, MSc, associate professor of medicine and clinical and translational science at the University of Pittsburgh in Pennsylvania.
PRESERVE was designed to enroll 7,680 patients, but enrollment was halted at 5,177 following a pre-planned interim analysis. There were no differences across study groups, no differences across primary endpoints and no differences across secondary endpoints, Weisbord said.
“The current standard of care for preventing contrast-associated acute kidney injury should be intravenous saline and no use of NAC,” he concluded.
Dual therapy with ticagrelor plus aspirin is more effective than either aspirin or ticagrelor in maintaining patency of saphenous vein grafts in coronary arterial bypass grafting, according to results from the Efficacy and Safety of Dual Acetylsalicylic Acid Plus Ticagrelor or Ticagrelor Alone Antiplatelet Strategy After Coronary Artery Bypass Surgery at 12 Months: Randomized Multicentre Trial.
Dual antiplatelet therapy (DAPT) has been found to reduce MACE in patients with acute coronary syndrome who undergo CABG, but this is the largest trial to date on DAPT and saphenous vein graft patency.
In the trial, 500 patients with acute coronary syndrome scheduled for CABG at six Chinese hospitals were randomized to DPAT, ticagrelor or aspirin. One-year follow up rates were high, between 92.2 percent and 94.9 percent. The primary outcomes were saphenous vein graft patency and non-occlusion. Secondary outcomes included MACE, recurrence of angina, atrial fibrillation and bleeding.
“Combination treatment gives better outcomes at one year than either agent alone,” said Qiang Zhao, MD, of Jian Tong University School of Medicine in Shanghai, China. “Aspirin alone had the worst outcomes in both patency and MACE as well as cardiovascular mortality, myocardial infarction and stroke.”
As expected, there were more bleeding events in the DAPT arm than the single-agent arms, but bleeds were minimal in all three arms, Zhao added.
Continuous or interrupted use of direct oral anticoagulation (DOAC) are both effective strategies for limiting device pocket hematoma following pacemaker or defibrillator implantation, according to results from A Randomized Controlled Trial of Continued versus Interrupted Novel Oral Anti-Coagulant at the Time of Device Surgery (BRUISE CONTROL-2).
Surgeons might prefer one strategy over the other depending on the situation, said co-principal investigator David H. Birnie, MD, director of the arrhythmia service at the University of Ottawa Heart Institute in Ontario.
An earlier trial, BRUISE CONTROL, found that uninterrupted anticoagulation with warfarin showed 80 percent fewer pocket hematomas compared to interrupted anticoagulation, Birnie said.
“With the new generation of DOACs, we had to do a new trial,” he said. “DOACs are currently used in the majority of patients with atrial fibrillation.”
Major clinical trials with DOACs have found that brief interruptions for procedures or surgery are associated with a three-fold increase in stroke and systemic embolism, Birnie said. But device pocket hematomas can require a prolonged halt to anticoagulation, which increases the risk of thromboembolism and is associated with increased risk of device pocket infection.
BRUISE CONTROL-2 was designed for 846 patients, but was stopped early after a second pre-specified interim analysis. A total of 662 patients were enrolled between April 2013 and June 2017 — 328 in the continuous DOAC arm and 334 in the interrupted DOAC arm.
The primary or secondary outcomes between the two arms were similar, Birnie reported. He added that scenarios in which interruption of anticoagulation might lead to unacceptable harm or patients with high stroke risk might favor continuous DOAC.
The Ablation Preoperative Dabigatran in use Envision in Japan (ABRIDGE-J) trial compared the efficacy and safety of minimally interrupted dabigatran to uninterrupted warfarin for catheter ablation for nonvalvular atrial fibrillation. Patients in the dabigatran arm had anticoagulation interrupted for one or two doses to allow for ablation.
There were no thromboembolic events in the dabigatran group and one event in the warfarin group in the first 90 days following ablation, reported principle investigator Ahihiko Nagami, MD, PhD, of the University of Tsukuba in Japan. Dabigatran also showed a significant reduction in the risk for major bleeding compared to warfarin.
“Anticoagulation with minimally interrupted dabigatran was associated with fewer bleeding complications than uninterrupted warfarin with no increase in thromboembolic events,” Nagami said.