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.

The association of perioperative red blood cell transfusions and decreased long-term survival after cardiac surgery.

BACKGROUND: Exposure to red blood cell (RBC) transfusions has been associated with increased mortality after cardiac surgery. We examined long-term survival for cardiac surgical patients who received one or two RBC units during index hospitalization. METHODS: Nine thousand seventy-nine consecutive patients undergoing coronary artery bypass graft, valve, or coronary artery bypass graft/valve surgery at eight centers in northern New England during 2001-2004 were examined after exclusions. A probabilistic match between the regional registry and the Social Security Administration's Death Master File determined mortality through June 30, 2006. Cox Proportional Hazard and propensity methods were used to calculate adjusted hazard ratios. RESULTS: Thirty-six percent of patients (n = 3254) were exposed to one or two RBC units. Forty-three percent of RBCs were given intraoperatively, 56% in the postoperative period and 1% were preoperative. Patients transfused were more likely to be anemic, older, smaller, female and with more comorbid illness. Survival was significantly decreased for all patients exposed to 1 or 2 U of RBCs during hospitalization for cardiac surgery compared with those who received none (P < 0.001). After adjustment for patient and disease characteristics, patients exposed to 1 or 2 U of RBCs had a 16% higher long-term mortality risk (adjusted hazard ratios = 1.16, 95% CI: 1.01-1.34, P = 0.035). CONCLUSIONS: Exposure to 1 or 2 U of RBCs was associated with a 16% increased hazard of decreased survival after cardiac surgery.

10-year follow-up of patients with and without mediastinitis.

Mediastinitis is a dreaded complication of CABG surgery. Short-term outcomes have been described, but there have been only a few long-term studies. We examined the survival of patients undergoing isolated CABG surgery between 1992 and 2001. Mediastinitis was identified during the index admission. Proportional hazards regression was used to calculate adjusted hazard ratios (HR) and 95% confidence intervals (CI 95%). Among 36,078 consecutive patients, there were 5749 deaths during 148,319 person years of follow-up. There were 418 cases of mediastinitis (1.16%). The incidence of death was 11.15 per 100 person/years with mediastinitis and 3.81 deaths/100 person years without. (P < 0.001). We also examined the mortality rates of patients who survived at least 6 months after their CABG surgery. Patients with mediastinitis had an incidence rate of 5.70 deaths per 100 person/years while those without had a rate of 2.66 deaths per 100 person/years (P < 0.001). After adjustment for baseline differences in patient and disease characteristics, the hazard ratio was 2.12 (CI95% = 1.86,2.58; P < 0.001). The adjusted hazard ratios for patients who survived 6 months postsurgery was 1.70 (CI95% = 1.36,2.13; P < 0.001). Mediastinitis is associated with a marked increase in both acute and long-term mortality rates.

Determination of etiologic mechanisms of strokes secondary to coronary artery bypass graft surgery.

BACKGROUND AND PURPOSE: Current research focused on stroke in the setting of coronary artery bypass graft (CABG) surgery has missed important opportunities for additional understanding by failing to consider the range of different stroke mechanisms. We developed and implemented a classification system to identify the distribution and timing of stroke subtypes. METHODS: We conducted a regional study of 388 patients with the diagnosis of stroke after isolated CABG surgery in northern New England from 1992 to 2000. Data were collected on patient and disease characteristics, intraoperative and postoperative care, and outcomes. Stroke etiology was classified into 1 of the following: hemorrhage, thromboembolic (embolic, thrombotic, lacunar), hypoperfusion, other (subtype not listed above), multiple (>or=2 competing mechanisms), or unclassified (unknown mechanism). The reliability of the classification system was determined by percent agreement and kappa statistics. RESULTS: Embolic strokes accounted for 62.1% of strokes, followed by multiple etiologies (10.1%), hypoperfusion (8.8%), lacunar (3.1%), thrombotic (1.0%), and hemorrhage (1.0%). There were 54 strokes with unknown etiology (13.9%). There were no strokes classified as "other." Nearly 45% (105/235) of the embolic and 56% (18/32) of hypoperfusion strokes occurred within the first postoperative day. CONCLUSIONS: We used a locally developed classification system to determine the etiologic mechanism of 388 strokes secondary to CABG surgery. The principal etiologic mechanism was embolic, followed by stroke having multiple mechanisms and hypoperfusion. Regardless of mechanism, strokes predominantly occurred within the first postoperative day.

Intra- and postoperative predictors of stroke after coronary artery bypass grafting.

BACKGROUND: Stroke is a devastating complication of coronary artery bypass graft surgery. An individual's risk of stroke is based in part on preoperative characteristics but also on intra- and postoperative factors. We developed a risk prediction model for stroke based on factors in intra- and postoperative care, after adjusting for a patient's preoperative risk. METHODS: We conducted a regional prospective study of 11,825 consecutive patients undergoing coronary artery bypass graft surgery surgery from 1996 to 2001. Data were collected on patient and disease characteristics, intra- and postoperative care and course, and outcomes. Stroke was defined as "a new focal neurologic deficit which appears and is still at least partially evident more than 24 hours after its onset." Logistic regression identified significant predictors of stroke. RESULTS: The incidence of stroke was 1.5%. The regression model significantly predicted the occurrence of stroke. As compared with cardiopulmonary bypass for less than 90 minutes, cardiopulmonary bypass for 90 to 113 minutes, odds ratio = 1.59, p = 0.022), cardiopulmonary bypass for 114 minutes or more (odds ratio = 2.36, p < 0.001), atrial fibrillation (odds ratio = 1.82, p < 0.001), and prolonged inotrope use (odds ratio = 2.59, p = 0.001) significantly improved our ability to predict stroke. Nearly 75% of all strokes occurred among the 90% of patients at low or medium preoperative risk. CONCLUSIONS: The inclusion of factors associated with intra- and postoperative care and course significantly improved the prediction model. Most strokes occurred among patients at low or medium preoperative risk, suggesting that many of these strokes may be preventable. Reduction in stroke risk may require modifications in intra- and postoperative care and course.

Development and validation of a prediction model for strokes after coronary artery bypass grafting.

BACKGROUND: A prospective study of patients undergoing coronary artery bypass graft surgery (CABG) was conducted to identify patient and disease factors related to the development of a perioperative stroke. A preoperative risk prediction model was developed and validated based on regionally collected data. METHODS: We performed a regional observational study of 33,062 consecutive patients undergoing isolated CABG surgery in northern New England between 1992 and 2001. The regional stroke rate was 1.61% (532 strokes). We developed a preoperative stroke risk prediction model using logistic regression analysis, and validated the model using bootstrap resampling techniques. We assessed the model's fit, discrimination, and stability. RESULTS: The final regression model included the following variables: age, gender, presence of diabetes, presence of vascular disease, renal failure or creatinine greater than or equal to 2 mg/dL, ejection fraction less than 40%, and urgent or emergency. The model significantly predicted (chi(2) [14 d.f.] = 258.72, p < 0.0001) the occurrence of stroke. The correlation between the observed and expected strokes was 0.99. The risk prediction model discriminated well, with an area under the relative operating characteristic curve of 0.70 (95% CI, 0.67 to 0.72). In addition, the model had acceptable internal validity and stability as seen by bootstrap techniques. CONCLUSIONS: We developed a robust risk prediction model for stroke using seven readily obtainable preoperative variables. The risk prediction model performs well, and enables a clinician to estimate rapidly and accurately a CABG patient's preoperative risk of stroke.

Insulin increases neutrophil count and phagocytic capacity after cardiac surgery.

UNLABELLED: We previously reported that a continuous insulin infusion improves neutrophil phagocytic function after cardiac surgery in diabetic patients. These data suggested that hyperglycemia impairs neutrophil function, and because nondiabetic patients also experience hyperglycemia during cardiac surgery, we hypothesized that a continuous insulin infusion would improve glucose control and neutrophil function in nondiabetic cardiac surgical patients. Patients were randomized to receive either no insulin (Control group) or a continuous insulin infusion (Insulin group), with glucose measurements every 10 min during cardiopulmonary bypass (CPB). Blood glucose was significantly lower in the Insulin group immediately after surgery but not during surgery. When assessed as the percentage of phagocytic cells, neutrophil function was similar in the Control and Insulin groups at baseline (55% and 57%, respectively) and after CPB (38% and 43%, respectively). However, a quantitative determination of neutrophil phagocytic activity showed that whole blood neutrophil phagocytic capacity increased significantly in both groups at 60 min after CPB when compared with their respective baseline values and that the increase in total neutrophil phagocytic capacity was significantly more in the Insulin group compared with the Control group (P = 0.036). This observation was primarily due to a larger increase in the peripheral blood neutrophil count and not to increased activation of neutrophils. IMPLICATIONS: IV insulin, as used in this study, had effects on blood glucose only after cardiac surgery, when it was associated with an increased neutrophil count and a greater total capacity of peripheral blood neutrophils to ingest foreign particles.