Unravelling the Difference Between Men and Women in Post-CABG Survival.

Objectives: Women have a worse prognosis after coronary artery bypass grafting (CABG) surgery compared to men. We sought to quantify to what extent this difference in post-CABG survival could be attributed to sex itself, or whether this was mediated by difference between men and women at the time of intervention. Additionally, we explored to what extent these effects were homogenous across patient subgroups. Methods: Time to all-cause mortality was available for 102,263 CABG patients, including 20,988 (21%) women, sourced through an individual participant data meta-analysis of five cohort studies. Difference between men and women in survival duration was assessed using Kaplan-Meier estimates, and Cox's proportional hazards model. Results: During a median follow-up of 5 years, 13,598 (13%) patients died, with women more likely to die than men: female HR 1.20 (95%CI 1.16; 1.25). We found that differences in patient characteristics at the time of CABG procedure mediated this sex effect, and accounting for these resulted in a neutral female HR 0.98 (95%CI 0.94; 1.02). Next we performed a priori defined subgroup analyses of the five most prominent mediators: age, creatinine, peripheral vascular disease, type 2 diabetes, and heart failure. We found that women without peripheral vascular disease (PVD) or women aged 70+, survived longer than men (interaction p-values 0.04 and 6 × 10-5, respectively), with an effect reversal in younger women. Conclusion: Sex differences in post-CABG survival were readily explained by difference in patient characteristics and comorbidities. Pre-planned analyses revealed patient subgroups (aged 70+, or without PVD) of women that survived longer than men, and a subgroup of younger women with comparatively poorer survival.

Comparative effectiveness of revascularization strategies for early coronary artery disease: A multicenter analysis.

OBJECTIVES: The goal of this analysis was to examine the comparative effectiveness of coronary artery bypass grafting versus percutaneous coronary intervention among patients aged less than 60 years. METHODS: We performed a multicenter, retrospective analysis of all cardiac revascularization procedures from 2005 to 2015 among 7 medical centers. Inclusion criteria were age less than 60 years and 70% stenosis or greater in 1 or more major coronary artery distribution. Exclusion criteria were left main 50% or greater, ST-elevation myocardial infarction, emergency status, and prior revascularization procedure. After applying inclusion and exclusion criteria, the final study cohort included 1945 patients who underwent cardiac surgery and 2938 patients who underwent percutaneous coronary intervention. The primary end point was all-cause mortality stratified by revascularization strategy. Secondary end points included stroke, repeat revascularization, and 30-day mortality. We used inverse probability weighting to balance differences among the groups. RESULTS: After adjustment, there was no significant difference in 30-day mortality (surgery: 0.8%; percutaneous coronary intervention: 0.7%, P = .86) for patients with multivessel disease. Patients undergoing surgery had a higher risk of stroke (1.3% [n = 25] vs 0.07% [n = 2], P < .001). Overall, surgery was associated with superior 10-year survival compared with percutaneous coronary intervention (hazard ratio, 0.71; 95% confidence interval, 0.57-0.88; P = .002). Repeat procedures occurred in 13.4% (n = 270) of the surgery group and 36.4% (n = 1068) of the percutaneous coronary intervention group, with both groups mostly undergoing percutaneous coronary intervention as their second operation. Accounting for death as a competing risk, at 10 years, surgery resulted in a lower cumulative incidence of repeat revascularization compared with percutaneous coronary intervention (subdistribution hazard ratio, 0.34; 95% confidence interval, 0.28-0.40; P < .001). CONCLUSIONS: Among patients aged less than 60 years with 2-vessel disease that includes the left anterior descending or 3-vessel coronary artery disease, surgery was associated with greater long-term survival and decreased risk of repeat revascularization.

Cardiac Surgery Outcomes: A Case for Increased Screening and Treatment of Obstructive Sleep Apnea.

BACKGROUND: Because of the limited published information on complications that obstructive sleep apnea (OSA) patients experience during and after cardiac surgery, we investigated OSA as a risk factor for postoperative outcomes. METHODS: This project used the Northern New England Cardiovascular Disease Study Group's data collected between 2011 and 2017 based on The Society of Thoracic Surgeons Adult Cardiac Surgery Database Data Collections form. A retrospective analysis of 1555 patients with OSA and 10,450 patients without OSA across 5 medical centers undergoing isolated coronary artery bypass grafting, isolated valve surgery, and combined coronary artery bypass grafting valve surgery was conducted. We used 1:1 nearest-neighbor propensity score matching with no replacement to balance characteristics among patients with and without OSA. RESULTS: There was a statistically significant increased risk of postoperative pneumonia, increased length of total and postoperative stay, and time to initial extubation. Two outcomes trended toward significance: intra- and postoperative intraaortic balloon pump use. Outcomes that failed to show statistical significance were surgical site infection, atrial fibrillation, cerebrovascular accident, permanent pacemaker placement, and blood products given. A chart review conducted on a subset of the study cohort revealed that more than 40% of OSA patients did not receive continuous positive airway pressure or bilevel positive airway pressure therapy postoperatively during their hospitalization. CONCLUSIONS: Our study aligns with the literature in concluding that OSA has deleterious effects on postoperative outcomes of cardiac surgery patients. Further research to better stratify OSA patients by severity are still needed. Additionally heightened awareness of the need to screen, diagnose, and properly treat patients for OSA is needed.

Cardiology providers' recommendations for treatments and use of patient decision aids for multivessel coronary artery disease.

BACKGROUND: Rates of recommending percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) vary across clinicians. Whether clinicians agree on preferred treatment options for multivessel coronary artery disease patients has not been well studied. METHODS AND RESULTS: We distributed a survey to 104 clinicians from the Northern New England Cardiovascular Study Group through email and at a regional meeting with 88 (84.6%) responses. The survey described three clinical vignettes of multivessel coronary artery disease patients. For each patient vignette participants selected appropriate treatment options and whether they would use a patient decision aid. The likelihood of choosing PCI only or PCI/CABG over CABG only was modeled using a multinomial regression. Across all vignettes, participants selected CABG only as an appropriate treatment option 24.2% of the time, PCI only 25.4% of the time, and both CABG or PCI as appropriate treatment options 50.4% of the time. Surgeons were less likely to choose PCI over CABG (RR 0.14, 95% CI 0.03, 0.59) or both treatments over CABG only (RR 0.10, 95% CI 0.03, 0.34) relative to cardiologists. Overall, 65% of participants responded they would use a patient decision aid with each vignette. CONCLUSIONS: There is a lack of consensus on the appropriate treatment options across cardiologists and surgeons for patients with multivessel coronary artery disease. Treatment choice is influenced by both patient characteristics and clinician specialty.

The 30-Year Influence of a Regional Consortium on Quality Improvement in Cardiac Surgery.

BACKGROUND: The Northern New England Cardiovascular Disease Study Group (NNECDSG) was founded in 1987 as a regional consortium to improve cardiovascular quality in Maine, New Hampshire, and Vermont. We sought to assess the longitudinal impact of the NNECDSG on quality and cost of coronary artery bypass grafting (CABG) during the past 30 years. METHODS: Patients undergoing isolated CABG at 5 medical centers from 1987-2017 were retrospectively reviewed (n = 67,942). They were divided into 4 time periods: 1987-1999 (n = 36,885), 2000-2005 (n = 14,606), 2006-2011(n = 8470), and 2012-2017 (n = 7981). The first period was the time the NNECDSG initiated a series of quality improvement initiatives including data feedback, quality improvement training, process mapping, and site visits. RESULTS: Throughout the 4 time intervals, there was a consistent decline in in-hospital mortality, from 3.4% to 1.8% despite an increase in predicted risk of mortality (P < .001), and a significant decline in in-hospital morbidity, including return to the operating room for bleeding, acute kidney injury, mediastinitis, and low output failure (P < .001). Median length of stay decreased from 7 to 5 days (P < .001), which translated into potential savings of $82,722,023. There was a decrease in use of red blood cells from 3.1 units to 2.6 units per patient in the most current time, which translated into potential savings of $1,985,456. CONCLUSIONS: By using collaborative quality improvement initiatives, the NNECDSG has succeeded in significant, sustained improvements in quality and cost for CABG during the past 30 years. These data support the utility of a regional consortium in improving quality.

A multi-center analysis of readmission after cardiac surgery: Experience of The Northern New England Cardiovascular Disease Study Group.

BACKGROUND: Readmissions after cardiac surgery are common and associated with increased morbidity, mortality and cost of care. Policymakers have targeted coronary artery bypass grafting to achieve value-oriented health care milestones. We explored the causes of readmission following cardiac surgery among a regional consortium of hospitals. METHODS: Using administrative data, we identified patients readmitted to the same institution within 30 days of cardiac surgery. We performed standardized review of readmitted patients' medical records to identify primary and secondary causes of readmission. We evaluated causes of readmission by procedure and tested for univariate associations between characteristics of readmitted patients and nonreadmitted patients in our clinical registry. RESULTS: Of 2218 cardiac surgery patients, 272 were readmitted to the index hospital within 30 days for a readmission rate of 12.3%. Median time to readmission was 9 days (interquartile range 4-16 days) and only 13% of patients were evaluated in-office before readmission. Readmitted patients were more likely to have had valve surgery (31.3% vs 22.7%) than patients not readmitted. Readmitted patients were also more likely to have preoperative creatinine more than or equal to 2 mg/dL (P = .015) or congestive heart failure (CHF) (P = .034), require multiple blood transfusions or sustained inotropic support (P < .001), and experience postoperative atrial fibrillation (P = .022) or renal insufficiency (P < .001). Infection (26%), pleural or pericardial effusion (19%), arrhythmia (16%), and CHF (11%) were the most common primary etiologies leading to readmission. CONCLUSIONS: Ensuring early follow-up for high-risk patient groups while improving early detection and management of the principal drivers of readmission represent promising targets for decreasing readmission rates.

Tissue versus mechanical aortic valve replacement in younger patients: A multicenter analysis.

OBJECTIVE: The goal of this study was to examine the long-term survival of patients between the ages of 50 and 65 years who underwent tissue versus mechanical aortic valve replacement (AVR) in a multicenter cohort. METHODS: A multicenter, retrospective analysis of all AVR patients (n = 9388) from 1991 to 2015 among 7 medical centers reporting to a prospectively maintained clinical registry was conducted. Inclusion criteria were: patients aged 50 to 65 years who underwent isolated AVR. Baseline comorbidities were balanced using inverse probability weighting for a study cohort of 1449 AVRs: 840 tissue and 609 mechanical. The primary end point of the analysis was all-cause mortality. Secondary end points included in-hospital morbidity, 30-day mortality, length of stay, and risk of reoperation. RESULTS: During the study period, there was a significant shift from mechanical to tissue valves (P < .001). There was no significant difference in major in-hospital morbidity, mortality, or length of hospitalization. Also, there was no significant difference in adjusted 15-year survival between mechanical versus tissue valves (hazard ratio, 0.87; 95% confidence interval [CI], 0.67-1.13; P = .29), although tissue valves were associated with a higher risk of reoperation with a cumulative incidence of 19.1% (95% CI, 14.4%-24.3%) versus 3.0% (95% CI, 1.7%-4.9%) for mechanical valves. The reoperative 30-day mortality rate was 2.4% (n = 2) for the series. CONCLUSIONS: Among patients 50 to 65 years old who underwent AVR, there was no difference in adjusted long-term survival according to prosthesis type, but tissue valves were associated with a higher risk of reoperation.

Surgical Atrial Fibrillation Ablation Improves Long-Term Survival: A Multicenter Analysis.

BACKGROUND: The Society of Thoracic Surgeons guidelines recommend surgical ablation (SA) at the time of concomitant mitral operations, aortic valve replacement, coronary artery bypass grafting (CABG), and aortic valve replacement plus CABG for patients in atrial fibrillation (AF). The goal of this analysis was to assess the influence of SA on long-term survival. METHODS: A retrospective analysis of 20,407 consecutive CABG or valve procedures from 2008 to 2015 among seven centers reporting to a prospectively maintained clinical registry was conducted. Patients undergoing operation with documented preoperative AF were included (n = 2,740). Patients receiving SA were compared with patients receiving no SA. The primary end point was all-cause mortality. Secondary end points included in-hospital morbidity and mortality. RESULTS: The frequency of SA was 23.1% (n = 634), and an increase was seen in the rate of SA over the study period (p < 0.001). Concomitant SA was performed in 16.2% of CABG, 30.6% of valve, and 24.3% of valve plus CABG procedures. A substantial improvement was found in unadjusted survival among patients undergoing SA (hazard ratio 0.54, 95% confidence interval: 0.42 to 0.70). Moreover, no differences were found in postoperative complications. SA did have longer bypass times (p < 0.001) but a shorter overall length of stay (p < 0.001). After risk adjustment, SA patients had an improved 5-year survival (hazard ratio 0.69, 95% confidence interval: 0.51 to 0.92), and the effect was observed across all operations. CONCLUSIONS: In a multicenter cohort of patients with AF, concomitant SA resulted in substantially improved long-term survival across patients who underwent CABG, valve, and valve plus CABG. These findings support current guidelines from The Society of Thoracic Surgeons that recommend broader application of concomitant SA.

Intensity of Glycemic Control Affects Long-Term Survival After Coronary Artery Bypass Graft Surgery.

BACKGROUND: A patient's hemoglobin (Hb) A1c level, regardless of diabetic status, is a measure of glycemic control. Studies have found it is an independent predictor of short-term death in patients undergoing coronary artery bypass grafting (CABG). In this study, we used preoperative HbA1c to assess whether levels are associated with short-term and long-term survival after CABG. METHODS: From a regional registry of consecutive cases, we identified 6,415 patients undergoing on-pump isolated CABG from 2008 to 2015 with documented preoperative HbA1c level. We defined four HbA1c groups: less than 5.7% (n = 1,713), 5.7% to 6.4% (n = 2,505), 6.5% to 8.0% (n = 1,377), and more than 8% (n = 820). Relationship to in-hospital outcomes and long-term survival was assessed. Outcome rates and hazard ratios were adjusted for patient and disease risk factors using multivariable logistic regression and Cox models. RESULTS: The study included 3,740 patients (58%) not diagnosed as having diabetes and 2,674 with diabetes. Prediabetes (HbA1c 5.7% to 6.4%) was documented in 52% (n = 1,933) of nondiabetic patients. Higher HbA1c values were associated with younger age, female sex, greater body mass index, more comorbid diseases, lower ejection fraction, more 3-vessel coronary disease, and recent myocardial infarction (p < 0.05 trend for all). After adjustment for patient risk, greater HbA1c values were not associated with higher rates of in-hospital death or morbidity. Long-term survival was significantly worse as HbA1c increased. Risk of death increased by 13% for every unit increase in HbA1c (adjusted hazard ratio, 1.13; 95% confidence interval, 1.07 to 1.19; p < 0.001). CONCLUSIONS: Preadmission glycemic control, as assessed by HbA1c, is predictive of long-term survival, with higher levels associated with poorer prognosis. Whether this risk can be modified by better glycemic control postoperatively remains to be determined.

Recovery of Kidney Dysfunction After Transcatheter Aortic Valve Implantation (from the Northern New England Cardiovascular Disease Study Group).

Acute Kidney Recovery (AKR) is a potential benefit of transcatheter aortic valve implantation (TAVI). We determined the incidence and predictors of AKR in a multicenter prospective registry of TAVI. After excluding patients on dialysis or who died within 48 hours postprocedure, we reviewed 1,502 consecutive patients underwent TAVI in Northern New England from 2012 to 2017. Patients were categorized into 3 groups based on the change in postprocedure estimated glomerular filtration rate (eGFR): Acute Kidney Injury (AKI, decrease in eGFR >25%), AKR (increase in eGFR >25%) or no change in kidney function on discharge creatinine following TAVI. We then focused in patients with baseline chronic kidney disease (CKD defined as eGFR ≤60 ml/min; n = 755) and developed multivariate predictor models to determine the clinical and procedural variables associated with AKR. For the TAVI cohort (n = 1,502), the overall incidence of AKR was 17.8%. AKR was threefold higher in patients with eGFR ≤60 ml/min as compared to those with eGFR >60 ml/min (26.6% vs 8.9%, p < 0.001). In the CKD population, hospital complications were similar among patients with no change in renal function and AKR; patients with AKI had a higher rate of hospital mortality, pacemaker implantation, length of hospitalization, and transfusions. Using multivariable logistic regression, moderate to severe lung disease, eGFR < 50 ml/min and previous aortic valve surgery were found to be independent predictors of AKR. Patients with diabetes mellitus, baseline anemia, and Society of thoracic surgeons score >6.1 were less likely to develop AKR. In conclusion, AKR occurred in 1 of 4 of all TAVI patients with baseline CKD and was a more frequent phenomena than AKI. Patients with decreased lung function, previous aortic valve surgery and worse baseline renal function were more likely to demonstrate AKR, whereas patients with diabetes mellitus, baseline anemia, and higher Society of thoracic risk scores were less likely to see improvements in renal function after TAVI.

Coronary Revascularization With Single Versus Bilateral Mammary Arteries: Is It Time to Change?

BACKGROUND: Arterial conduits are preferred to venous conduits for coronary artery bypass grafting because of longer patency. A single internal mammary artery (SIMA) is used routinely. Bilateral internal mammary arteries (BIMA) are used less frequently. We sought to determine whether BIMA were superior to SIMA. METHODS: From our regional registry of consecutive open heart operations, we identified 47,984 patients who underwent isolated coronary artery bypass grafting from 1992 to 2014. Of the 1,482 BIMA patients, 1,297 were propensity matched to a cohort of SIMA patients. Short-term outcomes were compared using standard statistical techniques. Long-term survival was compared using Kaplan-Meier estimators and compared using a log-rank test. RESULTS: BIMA patients were younger and had fewer comorbid conditions than SIMA patients. After propensity weighting, BIMA and SIMA patients were well matched. There was no difference in in-hospital outcomes for BIMA versus SIMA patients for mortality (1.2% [n = 15] vs 0.8% [n = 10], p = 0.315), stroke (0.7% [n = 9] vs 0.7% [n = 9), p = 1.000), bleeding (2.2% [n = 28] vs 2.8% [n = 36], p = 0.311), or mediastinitis (0.8% [n = 10] vs 0.9% [n = 12], p = 0.667). The median follow-up was 12 years. Survival was better for BIMA than SIMA (adjusted hazard ratio, 0.79; 95% confidence interval, 0.69 to 0.91; p < 0.001). Survival curves began to separate after 5 years. At 15 years, the absolute difference in survival was 8.4%. CONCLUSIONS: In a large regional experience, BIMA is associated with no upfront risk of adverse events and improved long-term survival compared with SIMA. Our results indicate that BIMA conduits should be considered more frequently during coronary artery bypass grafting due to their demonstrated survival advantage.

Should Diabetes Be a Contraindication to Bilateral Internal Mammary Artery Grafting?

BACKGROUND: This study evaluates the influence of bilateral internal mammary artery (BIMA) versus single internal mammary artery (SIMA) grafting on postoperative morbidity and long-term survival among diabetic patients undergoing coronary artery bypass grafting (CABG). METHODS: A multicenter, retrospective analysis of 47,984 consecutive CABGs performed from 1992 to 2014 at 7 medical centers was conducted. Among the study population, 1,482 CABGs with BIMA were identified, and 1,297 BIMA patients were propensity-matched to 1,297 SIMA patients. The study cohort for this analysis, drawn from matched data, included 430 diabetic patients: 217 SIMA and 213 BIMA. The primary endpoint was long-term survival. Secondary endpoints included postoperative morbidity, length of stay, and in-hospital mortality. RESULTS: The median duration of follow-up was 9.3 (range, 4.3 to 13.9) years. Among propensity-matched diabetic patients, there was no significant difference in age, body mass index, or major baseline comorbidities. The groups were also well matched on the number of diseased coronary arteries and number of distal anastomoses performed. There was no difference in the rate of mediastinitis or sternal dehiscence (p = 0.503) or in-hospital mortality (p = 0.758) between groups. Both groups had a similar median length of stay of 5 (range, 4 to 7) days. Diabetic patients who received a BIMA had significantly improved long-term survival when compared with SIMA patients (hazard ratio 0.75 [95% confidence interval 0.57 to 0.98], p = 0.034). CONCLUSIONS: Among diabetics undergoing CABG, use of BIMA grafting does not result in increased in-hospital morbidity or mortality and confers a long-term survival advantage when compared with SIMA grafting. Thus, diabetic patients should be considered for BIMA grafting more frequently.

Optimal Timing From Myocardial Infarction to Coronary Artery Bypass Grafting on Hospital Mortality.

BACKGROUND: Whether delaying coronary artery bypass grafting (CABG) after myocardial infarction (MI) is associated with better outcomes or is an unnecessary use of health care resources is unclear. This study investigated the relationship between MI-to-CABG timing on in-hospital death. METHODS: From the Northern New England Cardiovascular Disease Study Group (NNE) Cardiac Surgery Registry we identified 3,060 isolated CABG patients with prior MI from 2008 to 2014. We compared in-hospital death by MI-to-CABG timing of less than 1 day, 1 to 2 days, 3 to 7 days, and 8 to 21 days. We adjusted for patient characteristics using logistic regression. RESULTS: Among patients with prior MI, CABG was performed within 1 day for 99 (3.2%), 1 to 2 days for 369 (12.1%), 3 to 7 days for 1,966 (64.3%), and 8 to 21 days for 626 (20.5%) patients. NNE-predicted mortality was similar for patients operated on within 1 day (1.8%), 1 to 2 days (1.8%), and 3 to 7 days (1.9%), but was higher for 8 to 21 days (2.4%) of MI. Crude in-hospital mortality was higher for those with MI-to-CABG time of less than 1 day (5.1%) compared with 1 to 2 days (1.6%), 3 to 7 days (1.6%), and 8 to 21 days (2.7%, p = 0.044). Adjusted in-hospital mortality remained high for less than 1 day (5.4%; 95% CI, 1.5% to 9.4%), and similar for 1 to 2 days (1.8%; 95% CI, 0.4% to 3.1%), 3 to 7 days (1.7%; 95% CI, 1.1% to 2.3%), and 8 to 21 days (2.3%; 95% CI, 1.2% to 3.3%) between MI and CABG. CONCLUSIONS: Patients operated on 1 to 2 days and 3 to 7 days after MI had a similar mortality rate, suggesting it may be possible to reduce the MI-to-CABG interval for some patients without sacrificing outcomes. Patients operated on within 1 day after MI had a higher mortality rate.

Improving patients' readiness for coronary artery bypass graft surgery.

BACKGROUND: Preoperative interventions improve outcomes for patients after coronary artery bypass surgery (CABG). OBJECTIVE: To reduce mortality for patients undergoing urgent CABG. METHODS: Eight centers implemented preoperative aspirin and statin, preinduction heart rate less than 80/min, hematocrit greater than 30%, blood sugar less than 150 mg/dL (8.3 mmol/L), and delayed surgery at least 3 days after a myocardial infarction. Data were collected on the last 150 isolated, urgent CABGs at each center (n=1200). A "bundle" score of 0 to 100 was calculated for each patient to represent the percentage of interventions used. RESULTS: Scores ranged from 33 to 100. About 56% of patients had a perfect score. Crude mortality and composite rates were lower in patients with higher scores, but once adjusted for patient and disease characteristics, the difference in scores was not significant. Higher scores were associated with shorter intubation: 6.0 hours (score 100), 8.0 hours (score 80-99), 8.4 hours (score<80) (log-rank P<.001). Median length of stay was shorter for patients with higher scores: 5 days (score 100), 6 days (scores 80-99), and 6 days (scores <80) (log-rank P<.001). CONCLUSION: Implementation of interventions to optimize patients' "readiness for surgery" is associated with shorter intubation times and shorter hospital stays after CABG.

Geographic variability in potentially discretionary red blood cell transfusions after coronary artery bypass graft surgery.

OBJECTIVE: A number of established regional quality improvement collaboratives have partnered to assess and improve care across their regions under the umbrella of the Cardiac Surgery Quality Improvement (IMPROVE) Network. The first effort of the IMPROVE Network has been to assess regional differences in potentially discretionary transfusions (<3 units red blood cells [RBCs]). METHODS: We examined 11,200 patients undergoing isolated nonemergent coronary artery bypass graft surgery across 56 medical centers in 4 IMPROVE Network regions between January 2008 and June 2012. Each center submitted the most recent 200 patients who received 0, 1, or 2 units of RBC transfusion during the index admission. Patient and disease characteristics, intraoperative practices, and percentage of patients receiving RBC transfusions were collected. Region-specific transfusion rates were calculated after adjusting for pre- and intraoperative factors among region-specific centers. RESULTS: There were small but significant differences in patient case mix across regions. RBC transfusions of 1 or 2 units occurred among 25.2% of coronary artery bypass graft procedures (2826 out of 11,200). Significant variation in the number of RBC units used existed across regions (no units, 74.8% [min-max, 70.0%-84.1%], 1 unit, 9.7% [min-max, 5.1%-11.8%], 2 units, 15.5% [min-max, 9.1%-18.2%]; P < .001). Variation in overall transfusion rates remained after adjustment (9.1%-31.7%; P < .001). CONCLUSIONS: Delivery of small volumes of RBC transfusions was common, yet varied across geographic regions. These data suggest that differences in regional practice environments, including transfusion triggers and anemia management, may contribute to variability in RBC transfusion rates.

Embolic activity during in vivo cardiopulmonary bypass.

Neurologic injury after cardiac surgery is principally associated with emboli. Although much work has focused on surgical sources of emboli, less attention has been focused on emboli associated with the heart-lung machine. We tested whether emboli are associated with discrete processes during cardiopulmonary bypass (CPB). One hundred patients undergoing cardiothoracic surgery were enrolled between April 2008 and May 2011 at a single medical center. During each surgical procedure, emboli were counted in three CPB locations: the venous side (Channel 1), before the arterial line filter (Channel 2), and after the arterial line filter (Channel 3). We used prespecified event markers to identify perfusionist interventions. Identical circuits were used on all patients. Of the 100 patients enrolled, 62 underwent isolated coronary artery bypass grafting (CABG), 17 underwent isolated valve operations, and 21 underwent CABG plus valve. Median counts across Channels 1, 2, and 3 were 69,853, 3,017, and 1,251, respectively. The greatest contributor to emboli in Channels 1, 2, and 3, respectively, were achieving the calculated CPB flow, opening of the electronic arterial line clamp, and introducing a hemofilter. The circuit technology was efficient in reducing total emboli counts from Channels 1-2 irrespective of the size of the emboli. Nearly 71% of all emboli 30-100 microm in size were removed from the circuit between Channels 2 and 3. No significant association was found between emboli counts and S100B release. Emboli occur frequently during CPB and are predominantly associated with the initiation of bypass, operation of the electronic arterial line clamp, and the initiation of a hemofilter. Continued work to reduce the occurrence of emboli is warranted.

Impact of perioperative acute kidney injury as a severity index for thirty-day readmission after cardiac surgery.

BACKGROUND: Of patients undergoing cardiac surgery in the United States, 15% to 20% are re-hospitalized within 30 days. Current models to predict readmission have not evaluated the association between severity of postoperative acute kidney injury (AKI) and 30-day readmissions. METHODS: We collected data from 2,209 consecutive patients who underwent either coronary artery bypass or valve surgery at 7 member hospitals of the Northern New England Cardiovascular Disease Study Group Cardiac Surgery Registry between July 2008 and December 2010. Administrative data at each hospital were searched to identify all patients readmitted to the index hospital within 30 days of discharge. We defined AKI stages by the AKI Network definition of 0.3 or 50% increase (stage 1), twofold increase (stage 2), and a threefold or 0.5 increase if the baseline serum creatinine was at least 4.0 (mg/dL) or new dialysis (stage 3). We evaluate the association between stages of AKI and 30-day readmission using multivariate logistic regression. RESULTS: There were 260 patients readmitted within 30 days (12.1%). The median time to readmission was 9 (interquartile range, 4 to 16) days. Patients not developing AKI after cardiac surgery had a 30-day readmission rate of 9.3% compared with patients developing AKI stage 1 (16.1%), AKI stage 2 (21.8%), and AKI stage 3 (28.6%, p < 0.001). Adjusted odds ratios for AKI stage 1 (1.81; 1.35, 2.44), stage 2 (2.39; 1.38, 4.14), and stage 3 (3.47; 1.85 to 6.50). Models to predict readmission were significantly improved with the addition of AKI stage (c-statistic 0.65, p = 0.001) and net reclassification rate of 14.6% (95% confidence interval: 5.05% to 24.14%, p = 0.003). CONCLUSIONS: In addition to more traditional patient characteristics, the severity of postoperative AKI should be used when assessing a patient's risk for readmission.

Preoperative white blood cell count and risk of 30-day readmission after cardiac surgery.

Approximately 1 in 5 patients undergoing cardiac surgery are readmitted within 30 days of discharge. Among the primary causes of readmission are infection and disease states susceptible to the inflammatory cascade, such as diabetes, chronic obstructive pulmonary disease, and gastrointestinal complications. Currently, it is not known if a patient's baseline inflammatory state measured by crude white blood cell (WBC) counts could predict 30-day readmission. We collected data from 2,176 consecutive patients who underwent cardiac surgery at seven hospitals. Patient readmission data was abstracted from each hospital. The independent association with preoperative WBC count was determined using logistic regression. There were 259 patients readmitted within 30 days, with a median time of readmission of 9 days (IQR 4-16). Patients with elevated WBC count at baseline (10,000-12,000 and >12,000 mm(3)) had higher 30-day readmission than those with lower levels of WBC count prior to surgery (15% and 18% compared to 10%-12%, P = 0.037). Adjusted odds ratios were 1.42 (0.86, 2.34) for WBC counts 10,000-12,000 and 1.81 (1.03, 3.17) for WBC count > 12,000. We conclude that WBC count measured prior to cardiac surgery as a measure of the patient's inflammatory state could aid clinicians and continuity of care management teams in identifying patients at heightened risk of 30-day readmission after discharge from cardiac surgery.

Impact of preoperative left ventricular ejection fraction on long-term survival after aortic valve replacement for aortic stenosis.

BACKGROUND: The survival of patients who undergo aortic valve replacement (AVR) for severe aortic stenosis with reduced preoperative ejection fractions (EFs) is not well described in the literature. METHODS AND RESULTS: Patients undergoing AVR for severe aortic stenosis were analyzed using the Northern New England Cardiovascular Disease Study Group surgical registry. Patients were stratified by preoperative EF (≥50%, 40%-49%, and <40%) and concomitant coronary artery bypass grafting. Crude and adjusted survival across strata of EF was estimated for patients up to 8 years beyond their index admission. A total of 5277 patients underwent AVR for severe aortic stenosis between 1992 and 2008. There were 727 (14%) patients with preoperative EF <40%. Preoperative EF had minimal effect on postoperative morbidity. There was no difference in 30-day mortality across EF strata among the isolated AVR cohort. Preserved EF conferred 30-day survival benefit among the AVR+coronary artery bypass grafting population (EF≥50%, 96%; EF<40%, 91%; P=0.003). Patients with preserved EF had significantly improved 6-month and 8-year survival compared with their reduced EF counterparts. CONCLUSIONS: Survival after AVR or AVR+coronary artery bypass grafting was most favorable among patients with preoperative preserved EF. However, patients with mild to moderately depressed EF experienced a substantial survival benefit compared with the natural history of medically treated patients. Furthermore, minor reductions of EF carried equivalent increased risk to those with more compromised function suggesting patients are best served when an AVR is performed before even minor reductions in myocardial function.

Limited blood transfusion does not impact survival in octogenarians undergoing cardiac operations.

BACKGROUND: We previously reported that transfusion of 1 to 2 units of red blood cells (RBCs) confers a 16% increased hazard of late death after cardiac surgical treatment. We explored whether a similar effect existed among octogenarians. METHODS: We enrolled 17,026 consecutive adult patients undergoing cardiac operations from 2001 to 2008 in northern New England. Patients receiving more than 2 units of RBCs or undergoing emergency operations were excluded. Early (to 6 months) and late (to 3 years, among those surviving longer than 6 months) survival was confirmed using the Social Security Death Index. We estimated the relationship between RBCs and survival, and any interaction by age (<80 years versus ≥80 years) or procedure. We calculated the adjusted hazard ratio (HR), and plotted adjusted survival curves. RESULTS: Patients receiving RBCs had more comorbidities irrespective of age. Patients 80 years of age or older underwent transfusion more often than patients younger than 80 years (51% versus 30%; p<0.001). There was no evidence of an interaction by age or procedure (p>0.05). Among patients younger than 80 years, RBCs significantly increased a patient's risk of early death [HR, 2.03; 95% confidence interval [CI], 1.47, 2.80] but not late death 1.21 (95%CI, 0.88, 1.67). RBCs did not increase the risk of early [HR, 1.47; 95% CI, 0.84, 2.56] or late (HR, 0.92 95% CI, 0.50, 1.69) death in patients 80 years or older. CONCLUSIONS: Octogenarians receive RBCs more often than do younger patients. Although transfusion of 1 to 2 units of RBCs increases the risk of early death in patients younger than 80 years, this effect was not present among octogenarians. There was no significant effect of RBCs in late death in either age group.