Operative strategies to reduce cerebral embolic events during on- and off-pump coronary artery bypass surgery: A stratified, prospective randomized trial.

OBJECTIVE: To determine the impact of different aortic clamping strategies on the incidence of cerebral embolic events during coronary artery bypass grafting (CABG). METHODS: Between 2012 and 2015, 142 patients with low-grade aortic disease (epiaortic ultrasound grade I/II) undergoing primary isolated CABG were studied. Those undergoing off-pump CABG were randomized to a partial clamp (n = 36) or clampless facilitating device (CFD; n = 36) strategy. Those undergoing on-pump CABG were randomized to a single-clamp (n = 34) or double-clamp (n = 36) strategy. Transcranial Doppler ultrasonography (TCD) was performed to identify high-intensity transient signals (HITS) in the middle cerebral arteries during periods of aortic manipulation. Neurocognitive testing was performed at baseline and 30-days postoperatively. The primary endpoint was total number of HITS detected by TCD. Groups were compared using the Mann-Whitney U test. RESULTS: In the off-pump group, the median number of total HITS were higher in the CFD subgroup (30.0; interquartile range [IQR], 22-43) compared with the partial clamp subgroup (7.0; IQR, 0-16; P < .0001). In the CFD subgroup, the median number of total HITS was significantly lower for patients with 1 CFD compared with patients with >1 CFD (12.5 [IQR, 4-19] vs 36.0 [IQR, 25-47]; P = .001). In the on-pump group, the median number of total HITS was 10.0 (IQR, 3-17) in the single-clamp group, compared with 16.0 (IQR, 4-49) in the double-clamp group (P = .10). There were no differences in neurocognitive outcomes across the groups. CONCLUSIONS: For patients with low-grade aortic disease, the use of CFDs was associated with an increased rate of cerebral embolic events compared with partial clamping during off-pump CABG. A single-clamp strategy during on-pump CABG did not significantly reduce embolic events compared with a double-clamp strategy.

Diabetes and the Association of Postoperative Hyperglycemia With Clinical and Economic Outcomes in Cardiac Surgery.

OBJECTIVE: The management of postoperative hyperglycemia is controversial and generally does not take into account pre-existing diabetes. We analyzed clinical and economic outcomes associated with postoperative hyperglycemia in cardiac surgery patients, stratifying by diabetes status. RESEARCH DESIGN AND METHODS: Multicenter cohort study in 4,316 cardiac surgery patients operated on in 2010. Glucose was measured at 6-h intervals for 48 h postoperatively. Outcomes included cost, hospital length of stay (LOS), cardiac and respiratory complications, major infections, and death. Associations between maximum glucose levels and outcomes were assessed with multivariable regression and recycled prediction analyses. RESULTS: In patients without diabetes, increasing glucose levels were associated with a gradual worsening of outcomes. In these patients, hyperglycemia (≥180 mg/dL) was associated with an additional cost of $3,192 (95% CI 1,972 to 4,456), an additional hospital LOS of 0.8 days (0.4 to 1.3), an increase in infections of 1.6% (0.5 to 2.8), and an increase in respiratory complications of 2.6% (0.0 to 5.3). However, among patients with insulin-treated diabetes, optimal outcomes were associated with glucose levels considered to be hyperglycemic (180 to 240 mg/dL). This level of hyperglycemia was associated with cost reductions of $6,225 (-12,886 to -222), hospital LOS reductions of 1.6 days (-3.7 to 0.4), infection reductions of 4.1% (-9.1 to 0.0), and reductions in respiratory complication of 12.5% (-22.4 to -3.0). In patients with non-insulin-treated diabetes, outcomes did not differ significantly when hyperglycemia was present. CONCLUSIONS: Glucose levels <180 mg/dL are associated with better outcomes in most patients, but worse outcomes in patients with diabetes with a history of prior insulin use. These findings support further investigation of a stratified approach to the management of patients with stress-induced postoperative hyperglycemia based on prior diabetes status.

Readmissions after cardiac surgery: experience of the National Institutes of Health/Canadian Institutes of Health research cardiothoracic surgical trials network.

BACKGROUND: Readmissions are a common problem in cardiac surgery. The goal of this study was to examine the frequency, timing, and associated risk factors for readmission after cardiac operations. METHODS: A 10-center cohort study prospectively enrolled 5,158 adult cardiac surgical patients (5,059 included in analysis) to assess risk factors for infection after cardiac operations. Data were also collected on all-cause readmissions occurring within 65 days after the operation. Major outcomes included the readmission rate stratified by procedure type, cause of readmission, length of readmission stay, and discharge disposition after readmission. Multivariable Cox regression was used to determine risk factors for time to first readmission. RESULTS: The overall rate of readmission was 18.7% (number of readmissions, 945). When stratified by the most common procedure type, readmission rates were isolated coronary artery bypass grafting, 14.9% (n = 248); isolated valve, 18.3% (n = 337); and coronary artery bypass grafting plus valve, 25.0% (n = 169). The three most common causes of first readmission within 30 days were infection (17.1% [n = 115]), arrhythmia (17.1% [n = 115]), and volume overload (13.5% [n = 91]). More first readmissions occurred within 30 days (80.6% [n = 672]) than after 30 days (19.4% [n = 162]), and 50% of patients were readmitted within 22 days from the index operation. The median length of stay during the first readmission was 5 days. Discharge in 15.8% of readmitted patients (n = 128) was to a location other than home. Baseline patient characteristics associated with readmission included female gender, diabetes mellitus on medication, chronic obstructive pulmonary disease, elevated creatinine, lower hemoglobin, and longer operation time. More complex surgical procedures were associated with an increased risk of readmission compared with the coronary artery bypass grafting group. CONCLUSIONS: Nearly 1 of 5 patients who undergo cardiac operations require readmission, an outcome with significant health and economic implications. Management practices to avert in-hospital infections, reduce postoperative arrhythmias, and avoid volume overload offer important targets for quality improvement.

"Spot" ECGs Underestimate Atrial Fibrillation Recurrence After Surgical Ablation.

OBJECTIVE: : Historically, success of surgical treatment of atrial fibrillation (AF) has been measured by electrocardiograms (ECGs) at various intervals. However, continuous monitoring of cardiac rhythms by "autocapture" devices has recently become more available and convenient. The concordance of measurements of freedom from AF by these two techniques has not been reported after surgical ablation. METHODS: : Between August 2005 and May 2006, 47 patients at a single academic center underwent surgical ablation procedures for AF and had recurrence of AF assessed by both "spot" 12-lead ECG and autocapture event monitoring. Forty-one ablation procedures were concomitant with other cardiac surgery and six were stand alone, nonsternotomy procedures. Agreement between these diagnostic modes was measured using the κ statistic at 3, 6, and 12 months (κ of 1 is perfect agreement, 0 is no agreement). McNemar test was employed to determine whether agreement significantly changed from 3 to 12 months. RESULTS: : At 3 months follow-up, spot ECGs suggested that 81% (38 of 47) of surgical patients were free of any AF, whereas 1-week event recordings found only 70% (31 of 44) of patients were free of any AF. At 6 months, spot ECGs estimated that 87% (40 of 46) of surgical patients were free of AF; 1-week event recordings found only 74% (34 of 46) of patients were free of AF. At 12 months, spot ECGs estimated that 84% (26 of 31) of surgical patients were free of AF compared with only 68% (19 of 28) as measured by the 1-week event recorder. The κ measures (with 95% confidence interval) at 3, 6, and 12 months were 0.52 (0.24-0.80), 0.60 (0.32-0.87), and 0.63 (0.32-0.94) respectively, showing only moderate agreement. McNemar test showed no significant shift in agreement from 3 to 6 months (P = 0.7055), 3 to 12 months (P = 1.000), or 6 to 12 months (P = 1.000). There were no deaths or strokes, but one myocardial infarction among these 47 patients during 12 months follow-up. CONCLUSIONS: : "Spot" ECGs underestimate the incidence of recurrent AF after surgical ablation for AF and show poor agreement with the more reliable 1-week autocapture event recordings.