CANCARE RESEARCH
Explore previously published research highlights by topic, study type or publication date.
An automated research-discovery feed. Summaries are based on published abstracts and are not clinical recommendations.
Bivalirudin Versus Heparin and Protamine in Adult Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-Analysis.
Clinical takeaway The pooled trials did not establish a difference in major postoperative outcomes. The wide confidence interval for reexploration leaves substantial uncertainty and does not establish equivalence or safety.
Summary & abstract
Study summary
This systematic review pooled three randomized trials involving 407 adults undergoing cardiac surgery, comparing bivalirudin with unfractionated heparin for anticoagulation. Reexploration for hemorrhage, the primary outcome, did not differ significantly between groups (risk ratio 1.38, 95% confidence interval 0.42–4.48). No observable differences were reported in thromboembolic events, mortality, or postoperative transfusion requirements. All included trials had some concern for risk of bias, although interstudy heterogeneity was low across comparisons. The review also identified variability in bivalirudin dosing and therapeutic monitoring as limitations.
Study limitation: Only 407 patients were pooled, with risk-of-bias concerns and variable bivalirudin dosing and monitoring.
Published abstract
OBJECTIVES: To summarize the evidence on the morbidity, mortality, and transfusion requirements of adult patients undergoing cardiac surgery using bivalirudin for anticoagulation compared to unfractionated heparin (UFH). MEASUREMENTS AND MAIN RESULTS: A total of 407 patients in three randomized controlled trial (RCTs) were included for pooled analysis. There was no significant difference in the primary outcome; reexploration for hemorrhage between groups (risk ratio: 1.38, 95% confidence interval: 0.42 to 4.48). There were no observable differences in any of the secondary outcomes; thromboembolic events (myocardial infarction, stroke, pulmonary embolism), mortality, or postoperative transfusion requirements (packed red cells (PRC), platelets, cryoprecipitate, fresh frozen plasma (FFP)). All studies included were assessed to have some concern for risk of bias. Interstudy heterogeneity was low across all comparisons. CONCLUSION: Bivalirudin has not been shown to have any significant difference to UFH on clinical outcomes in patients undergoing cardiac surgery, and as per current international guidelines, can be considered for safe use in those patients for whom UFH is contraindicated. The study is limited by the bias of the included studies and the variability of bivalirudin drug dosage and its therapeutic monitoring; further, well-powered RCTs are required.
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Oxidative Stress and Postoperative Atrial Fibrillation: A Systematic Review and Meta-Analysis.
Clinical takeaway Oxidative stress biomarkers show sampling-site-dependent associations with POAF, with stronger signals in atrial tissue than blood. These findings do not establish a clinically useful prediction strategy.
Summary & abstract
Study summary
This systematic review included 31 studies involving 4,983 adults undergoing cardiac surgery and examined oxidative stress biomarkers associated with postoperative atrial fibrillation (POAF). Pooled POAF incidence was 30.4% (95% CI 27.4–33.5). Atrial oxidative stress biomarkers were higher among patients developing POAF (Hedges g 0.89, 95% CI 0.45–1.32), whereas corresponding blood measurements showed no statistically significant difference (g 0.13, 95% CI −0.04–0.30). The between-compartment difference was 0.76 (p=0.005), highlighting the importance of sampling site. Most included studies were at high risk of bias, and clinical utility remains unvalidated.
Study limitation: Most studies had high risk of bias, and heterogeneous sampling sites and timing limit interpretation and clinical applicability.
Published abstract
Postoperative atrial fibrillation (POAF) is the most common arrhythmia after cardiac surgery and is linked to higher mortality and hospitalizations. Oxidative injury may contribute to its development; therefore, we aimed to systematically evaluate the relationship between oxidative stress biomarkers and POAF. MEDLINE, Embase, and the Cochrane Library were searched from inception to August 2026 for studies reporting oxidative stress biomarkers and POAF in adults undergoing cardiac surgery. Altogether, 31 studies (4,983 patients) were included; most were at high risk of bias by QUIPS assessment. We pooled similar studies using random-effects meta-analysis, compared associations between atrial and circulating measurements using a three-level model with cluster-robust inference, and summarized the remaining studies by effect direction. Pooled POAF incidence was 30.4% (95% CI 27.4 to 33.5). Atrial oxidative stress biomarkers were higher in patients who developed POAF (Hedges g 0.89, 95% CI 0.45 to 1.32), but blood levels of the same biomarker showed no statistical significance (g 0.13, 95% CI -0.04 to 0.30; between-compartment difference of 0.76, p = 0.005). Among individual markers, preoperative malondialdehyde differed only modestly between groups, while circulating markers increased postoperatively. Atrial oxidase and pericardial myeloperoxidase activity showed the largest adjusted associations with POAF. Oxidative-stress associations with POAF depend on sampling site and timing. Atrial tissue measures show stronger associations than preoperative blood biomarkers, while early postoperative pericardial and circulating markers may reflect reperfusion injury. Because the evidence is heterogeneous, standardized prospective studies are needed to validate these biomarkers and determine their clinical utility.
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The effect of near-infrared spectroscopy guided intraoperative care on neurocognitive and functional outcomes after cardiac surgery: a systematic review and meta-analysis of randomised controlled trials.
Clinical takeaway NIRS-guided intraoperative care may reduce early cognitive decline after on-pump cardiac surgery, but benefits for mortality, stroke, delirium, and longer-term recovery remain unestablished.
Summary & abstract
Study summary
This meta-analysis included 17 randomized trials involving 2288 adults undergoing on-pump cardiac surgery, comparing intraoperative NIRS-guided management with usual care. NIRS guidance probably reduced early postoperative cognitive decline (RR 0.65, 95% CI 0.42–0.99; moderate-certainty evidence). Effects on stroke (RR 0.89, 95% CI 0.42–1.91), mortality (RR 0.84, 95% CI 0.47–1.52), and delirium (RR 0.78, 95% CI 0.56–1.09) remained uncertain, with low-certainty evidence. Trials were predominantly small and single-centre, with heterogeneous thresholds and intervention algorithms. Few assessed outcomes beyond 30 days; none assessed validated quality-of-life or functional measures.
Study limitation: Predominantly small, single-centre trials used heterogeneous NIRS protocols, and evidence on longer-term patient-centred outcomes was sparse.
Published abstract
BACKGROUND: Adverse neurocognitive and functional outcomes are common after cardiac surgery. Cerebral near-infrared spectroscopy (NIRS) monitors regional cerebral oxygen saturation, allowing clinicians to detect and reverse cerebral desaturation. We conducted a systematic review and meta-analysis of RCTs to evaluate whether intraoperative NIRS monitoring improves neurocognitive outcomes after cardiac surgery. METHODS: We searched CENTRAL, CINAHL, Embase, MEDLINE, PsycINFO, and Web of Science for RCTs comparing NIRS-guided intraoperative management with usual care in adults undergoing on-pump cardiac surgery, assessing the outcomes of postoperative cognitive decline, delirium, stroke, mortality, and functional recovery. We pooled data using random-effects meta-analysis and assessed certainty of evidence using GRADE methodology. RESULTS: We included 17 RCTs (N=2288). NIRS-guided management probably reduces early postoperative cognitive decline (risk ratio [RR] 0.65, 95% CI 0.42-0.99; I2=65%, moderate certainty), may have little or no effect on stroke (RR 0.89, 95% CI 0.42-1.91; low certainty) or mortality (RR 0.84, 95% CI 0.47-1.52; low certainty), and may have no effect on delirium (RR 0.78, 95% CI 0.56-1.09; I2=32%, low certainty). Findings were primarily derived from small, single-centre trials with heterogenous NIRS thresholds and intervention algorithms. Few studies evaluated outcomes beyond 30 days, and none evaluated validated measures of quality of life or function. CONCLUSIONS: Although NIRS-guided intraoperative care shows promise for reducing early postoperative cognitive decline after cardiac surgery, evidence of benefit for other neurocognitive or clinical outcomes remains limited. Large multicentre studies are needed to confirm its utility, refine intervention thresholds, and determine its impact on long-term cognition, function, and quality of life. Systematic review protocol. PROSPERO (CRD42022336468).
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Comparing High-Flow Nasal Cannula Therapy and Conventional Oxygen Therapy in Adult Patients Post-Cardiac Surgery: A Systematic Review and Meta-Analysis.
Clinical takeaway High-flow oxygen after cardiac surgery may reduce escalation of respiratory support, but the reported delirium signal warrants attention. The pooled findings do not establish a mortality or intubation benefit.
Summary & abstract
Study summary
This systematic review pooled 11 randomized trials involving 2473 adults recovering from cardiac surgery, comparing high-flow nasal cannula with conventional oxygen therapy. High-flow therapy reduced escalation of respiratory support (RR 0.71; 95% CI 0.55–0.93). However, delirium was more frequent with high-flow therapy (RR 3.63; 95% CI 1.80–7.30). Oxygenation and forced expiratory volume in 1 second improved, but there were no statistically significant differences in intubation, overall mortality, hospital or intensive care unit length of stay, or postoperative atrial fibrillation.
Study limitation: The abstract provides no absolute event rates or outcome-specific trial counts, limiting assessment of benefit magnitude and the delirium signal.
Published abstract
BACKGROUND: Cardiac surgery with cardiopulmonary bypass structurally alters respiratory mechanics and carries a substantial risk of postoperative morbidity. Historically, patients have routinely received conventional oxygen therapy (COT) following extubation. High- flow nasal cannula (HCNC) therapy has emerged as an innovative respiratory support system. By synthesizing all currently available high-quality randomized controlled trials (RCTs), this study aimed to rigorously evaluate the efficacy and safety of HFNC compared to COT, focusing primarily on determining the need for escalation of respiratory support. METHODOLOGY: A thorough electronic search was carried out in the PubMed, Embase, and Scopus databases from their inception to May 2026. Only RCTs were considered for analysis. A random-effects model was applied to compute pooled estimates and 95% confidence intervals (CIs). RESULTS: A total of 11 RCTs, comprising 2473 patients, were included in this systematic review and meta-analysis. HFNC had a statistically significant effect on reducing the requirement for escalation of respiratory support (risk ratio [RR] = 0.71; 95% CI, 0.55-0.93; p = 0.01). HFNC had a statistically significant effect on improving the arterial partial pressure of oxygen, as well as forced expiratory volume in 1 second, while also increasing delirium complications (RR = 3.63; 95% CI, 1.80-7.30; p = 0.0003). There were no statistically significant differences between the 2 approaches in the other secondary clinical and resource utilization outcomes, including intubation, overall mortality, hospital length of stay, intensive care unit length of stay, and postoperative atrial fibrillation. CONCLUSION: In adult patients recovering from cardiac surgery, HFNC therapy improves oxygenation and significantly curtails the need to escalate respiratory support compared to COT. However, these physiologic and intermediate clinical benefits do not translate into reductions in mortality, reintubation rate, or hospital length of stay and may come at the cost of increased postoperative delirium.
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