Biomedical subjects
W C Nugent
Publications and source records attributed to W C Nugent.
Predicting the risk of death from heart failure after coronary artery bypass graft surgery.
UNLABELLED: Heart failure is the most common cause of death among coronary artery bypass graft (CABG) patients. In addition, most variation in observed mortality rates for CABG surgery is explained by fatal heart failure. The purpose of this study was to develop a clinical risk assessment tool so that clinicians can rapidly and easily assess the risk of fatal heart failure while caring for individual patients. Using prospective data for 8,641 CABG patients, we used logistic regression analysis to predict the risk of fatal heart failure. In multivariate analysis, female sex, prior CABG surgery, ejection fraction <40%, urgent or emergency surgery, advanced age (70-79 yr and >80 yr), peripheral vascular disease, diabetes, dialysis-dependent renal failure and three-vessel coronary disease were significant predictors of fatal postoperative heart failure. A clinical risk assessment tool was developed from this logistic regression model, which had good discriminating characteristics (receiver operating characteristic clinical source = 0.75, 95% confidence interval: 0.71, 0.78). IMPLICATIONS: In contrast to previous cardiac surgical scoring systems that predicted total mortality, we developed a clinical risk assessment tool that evaluates risk of fatal heart failure. This distinction is relevant for quality improvement initiatives, because most of the variation in CABG mortality rates is explained by postoperative heart failure.
In health care, geography is destiny.
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Lung cancer staging and treatment in multidisciplinary trials: Cancer and Leukemia Group B cooperative group approach. Thoracic Surgeons of CALGB.
BACKGROUND: Aggressive routine surgical staging is necessary to evaluate patients to be treated on cooperative oncology protocols. Less than 1% of lung cancer patients in the United States are currently being treated in a clinical trial. Only with results from large, prospective trials can the questions of neoadjuvant and adjuvant therapy be answered. METHODS: An outline describing the schema of preoperative patient evaluation, surgical staging, and the definition of surgical staging and resection procedures appropriate for patients considered for cooperative group protocol is presented. Current Cancer and Leukemia Group B (CALGB) protocols are used in the discussion as examples of this systematic approach. CONCLUSIONS: Over the next few years, it will be important to enter the maximum number of patients into combined modality studies to identify the role of neoadjuvant treatment in lung cancer. Entry of patients into protocols will also make their pathological specimens and clinical information available for basic science research related to treatment results. Adherence to a logical sequence of patient evaluation as outlined above will optimize patient care, as well as accrual to cooperative group studies.
Innovative uses of a cardiothoracic database.
This report describes the activities of the Northern New England Cardiovascular Disease Study Group. The group consists of representatives from six institutions: Eastern Maine Medical Center in Bangor, and Maine Medical Center in Portland, ME; Optima Health Care in Manchester and Dartmouth-Hitchcock Medical Center in Lebanon, NH; Fletcher Allen Health Care in Burlington, VT; and Beth Israel-Deaconess Medical Center in Boston, MA. The Northern New England Cardiovascular Disease Study Group maintains a voluntary primary cardiac surgical database that has risk-stratified information on more than 60,000 consecutive patients who have undergone open heart surgical procedures in northern New England since 1987. In 1991, the group reported that significant variation in mortality rate existed between centers, a difference not explained by case mix. The finding led to a regional retrospective review of deaths in an effort to identify "mode of death." Mode of death is defined as that event that started the chain of events ultimately leading to the death of the patient. The most common mode of death was found to be low cardiac output syndrome. This information has led to a regional effort toward prevention, early recognition, and successful treatment of low cardiac output syndrome in the perioperative period.
ACC/AHA Guidelines for Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1991 Guidelines for Coronary Artery Bypass Graft Surgery). American College of Cardiology/American Heart Association.
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Reexploration for hemorrhage following coronary artery bypass grafting: incidence and risk factors. Northern New England Cardiovascular Disease Study Group.
OBJECTIVE: To assess mortality and risk factors associated with reexploration for hemorrhage in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Regional cohort study. Patient characteristics, treatment variables, and outcome measures were collected prospectively. SETTING: All 5 centers performing cardiac surgery in Maine, New Hampshire, and Vermont. PATIENTS: A consecutive cohort of 8586 patients undergoing isolated CABG between 1992 and 1995. MAIN OUTCOME MEASURES: Postoperative hemorrhage leading to reexploration, in-hospital mortality, and length of stay. RESULTS: A total of 305 patients (3.6%) underwent reexploration for bleeding. In these patients, in-hospital mortality was nearly 3 times higher (9.5% vs 3.3% for patients not requiring reoperation, P<.001) and average length of stay from surgery to discharge was significantly longer (14.5 days vs 8.6 days, P<.001). High rates of reexploration for hemorrhage were observed in patients with prolonged (> 150 minutes) cardiopulmonary bypass (39 [11.1%] of 351) and in those requiring an intra-aortic balloon pump intraoperatively (12 [8%] of 139). In multivariate analysis, older age, smaller body surface area, prolonged cardiopulmonary bypass, and number of distal anastomoses were associated with increased bleeding risks. The use of thrombolytic therapy within 48 hours of surgery was weakly but not significantly associated with the need for reexploration. Factors not significantly associated with reexploration included patient sex, preoperative ejection fraction, surgical priority, history of liver disease, myocardial infarction, prior CABG, renal failure, and diabetes mellitus. CONCLUSIONS: Hemorrhage requiring reexploration after CABG is associated with markedly increased mortality and length of stay. Patients predicted to have increased risks of bleeding may benefit from prophylactic use of aprotinin, aminocaproic acid, or other agents shown to reduce hemorrhage.
Results of a regional study of modes of death associated with coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group.
BACKGROUND: It is well known that surgeon-specific in-hospital mortality rates for coronary artery bypass grafting vary, but this aggregate measure does not suggest specific opportunities for improvement. METHODS: We performed a regional prospective study of 8,641 consecutive patients undergoing isolated coronary artery bypass grafting by all of the 23 cardiothoracic surgeons practicing in northern New England during the study period. Mode of death was assigned by an end points committee using predetermined definitions. Surgeons were ranked according to risk-adjusted mortality rates and grouped in terciles, and cause-specific mortality rates were determined. RESULTS: The mortality rate was 3.3% in the lowest surgeon mortality tercile and 5.8% in the highest tercile. Fatal heart failure accounted for 80.0% of the difference in aggregate mortality rates, ranging from 1.9% in lowest surgeon mortality tercile to 4.0% in the highest tercile (p < 0.001). Rates of other causes did not differ significantly across surgeon mortality terciles. Differences in rates of fatal heart failure could not be explained by differences in preoperative left ventricular dysfunction or other patient characteristics. CONCLUSIONS: Most of the difference in observed mortality rates across surgeons is attributable to differences in rates of heart failure.
Non-small cell lung cancer at the extremes of age: impact on diagnosis and treatment.
BACKGROUND: Early detection and surgical resection offers the highest likelihood of cure for patients with lung cancer. Patients presenting at the extremes of age may fail to benefit maximally from these interventions. To study the impact of age on stage, histology, symptom, and treatment of patients with non-small cell lung cancer, we undertook a retrospective review. METHODS: One thousand eight hundred two patients with non-small cell lung cancer were identified between 1983 and 1993. Patients were selected by age as less than 45 years (55 patients) and 80 years or more (108 patients), and their medical records were reviewed. RESULTS: Three younger patients (6%) presented with stage I or II disease, yet 15 (32%) underwent thoracic operation. Twenty-seven elderly patients (33%) presented with early stage disease and only 6% underwent operation. The median survival was significantly longer for the younger population with surgically resectable stages of disease (stage I to IIIA) (p < 0.05), whereas no significant difference in survival was seen for the two groups with advanced disease (stage IIIB and IV). CONCLUSIONS: Age significantly affects the presentation and treatment of non-small cell lung cancer patients. Although thoracic operation imparts the greatest survival advantage, this benefit is diminished due to advanced disease in the younger patients and lack of surgical intervention in the elderly.
Clinical applications of risk-assessment protocols in the management of individual patients.
BACKGROUND: Cardiac surgical databases are typically used to compare performance rather than to predict performance. Application of analytic techniques to representative clinical data allows for the creation of highly reliable prediction models for outcomes such as mortality after coronary artery bypass grafting. METHODS: The Northern New England Cardiovascular Disease Study Group collects clinical data from the six regional cardiac institutions. The four basic components of the one-page clinical data form are demographic information, comorbidity data, severity of illness data, and outcomes. From these, a mathematical model predicts the likelihood of inhospital mortality after coronary artery bypass grafting. RESULTS: The Northern New England Cardiovascular Disease Study Group mortality prediction rule was validated and found to predict and discriminate well. It is updated yearly based on the most current data. At Dartmouth-Hitchcock Medical Center, the rule has been combined with other decision-support tools based on American College of Cardiology/American Heart Association indications for coronary artery bypass grafting. These data are compared with data supplied by patients on their expectations for operation and their assessments of acceptable mortality risk. By expanding the database to include variables such as 5-year survival and additional outcomes, and additional interventions, an "electronic second opinion" is made available to clinicians. CONCLUSIONS: Although experience with decision-support tools has been positive, prediction rules have certain limitations. Their accuracy depends on data that are consistently tracked; thus, transfer to other patient populations must be approached with caution. The challenge for the future is to develop and validate similar techniques that apply to more difficult clinical situations.
A regional intervention to improve the hospital mortality associated with coronary artery bypass graft surgery. The Northern New England Cardiovascular Disease Study Group.
OBJECTIVE: To determine whether an organized intervention including data feedback, training in continuous quality improvement techniques, and site visits to other medical centers could improve the hospital mortality rates associated with coronary artery bypass graft (CABG) surgery. DESIGN: Regional intervention study. Patient demographic and historical data, body surface area, cardiac catheterization results, priority of surgery, comorbidity, and status at hospital discharge were collected on CABG patients in Northern New England between July 1, 1987, and July 31, 1993. SETTING: This study included all 23 cardiothoracic surgeons practicing in Maine, New Hampshire, and Vermont during the study period. PATIENTS: Data were collected on 15,095 consecutive patients undergoing isolated CABG procedures in Maine, New Hampshire and Vermont during the study period. INTERVENTIONS: A three-component intervention aimed at reducing CABG mortality was fielded in 1990 and 1991. The interventions included feedback of outcome data, training in continuous quality improvement techniques, and site visits to other medical centers. MAIN OUTCOME MEASURE: A comparison of the observed and expected hospital mortality rates during the postintervention period. RESULTS: During the postintervention period, we observed the outcomes for 6488 consecutive cases of CABG surgery. There were 74 fewer deaths than would have been expected. This 24% reduction in the hospital mortality rate was statistically significant (P = .001). This reduction in mortality rate was relatively consistent across patient subgroups and was temporally associated with the interventions. CONCLUSION: We conclude that a multi-institutional, regional model for the continuous improvement of surgical care is feasible and effective. This model may have applications in other settings.
Cost-effectiveness of preoperative autologous donation in coronary artery bypass grafting.
Concern about the safety of the allogeneic blood supply has made preoperative autologous blood donation (PAD) routine before major noncardiac operations. However, the costs and benefits of PAD in elective coronary artery bypass grafting (CABG) are not well established. We used decision analysis to (1) calculate the cost-effectiveness of PAD in CABG, expressed as cost per year of life saved, and (2) compare the health benefits of reducing allogeneic transfusions with the potential risks of autologous blood donation by patients with coronary artery disease. A prospective study of 18 institutions provided data on transfusion practice and blood product costs in CABG. On average, PAD in CABG costs $508,000 to $909,000 per quality-adjusted year of life saved, depending on the number of units donated. Preoperative autologous blood donation is more cost-effective (as low as $518,000 per year of life saved) when targeted to younger patients undergoing CABG at centers with high transfusion rates. The cost-effectiveness of PAD is strongly dependent on estimates of posttransfusion hepatitis incidence, but less so on plausible estimates of the current risk of human immunodeficiency virus transmission. Although the actual risk of PAD is uncertain, even a small fatality risk (> 1 per 101,000 donations) associated with blood donation by patients awaiting CABG negates all life expectancy benefits of PAD. At current costs, PAD by patients awaiting CABG is not cost-effective, producing small health benefits at high societal cost. For the individual patient, the risk of donating blood before CABG may well outweigh the benefits associated with fewer allogeneic transfusions.
Playing by the numbers: how collecting outcomes data changed by life.
The Northern New England Cardiovascular Study Group has been using clinical epidemiology to analyze outcomes data in patients undergoing cardiac surgical procedures to answer three questions: (1) for the surgeon: how am I doing?, (2) for the patient: what are my chances?, and (3) for society: can outcomes data be voluntarily collected and organized in a way to improve care delivery? The Dartmouth-Hitchcock Medical Center cardiac surgery program has combined this regional outcomes data with the internal development of critical pathways; with evaluations of patient expectations, patient satisfaction, and patient functional health; and with innovative techniques of data display in an effort to improve the cardiac surgical outcomes in patients at the center. The length of stay has declined, and both the mortality rate and readmission rate have remained stable.
Benchmarking cardiac surgery: a regional initiative to improve outcomes. Interview by Reggi Veatch.
Many of the clinical benchmarking projects featured in the Lead Story are designed to produce quick results. The Northern New England Cardiovascular Disease Study Group (NNE), by contrast, is a long-term effort to improve patients' functional health status. Formed in 1987, NNE is a voluntary consortium comprising all providers of open heart surgery in Maine, New Hampshire, and Vermont--five facilities and 28 surgeons. Although NNE is just beginning to focus on best practices within the region, its early benchmarking efforts have produced a collaborative environment in which clinical information is now readily shared. Because of this, its accomplishments have been striking: the creation of a database that includes information on more than 18,000 patients; the development of a highly accurate mortality prediction tool for patients facing coronary bypass surgery; and a 24 percent decrease in regional operative mortality following coronary artery bypass graft (CABG) surgery.
Should a patient with a treated cancer be offered an open heart operation?
The unknown but presumably reduced life expectancy of patients with malignant neoplasms may dissuade surgeons from performing necessary coronary and valvular heart operations. There is also concern for recrudescence of cancer as a result of an impaired immune system after cardiopulmonary bypass. We analyzed the records of 2,190 patients who underwent cardiac operations requiring extracorporeal circulation between 1988 and 1990. Of these, 46 patients had previously been treated for malignancy other than nonmelanoma skin cancer. Open heart operations were performed in patients with cardiac symptoms only in the absence of tumor recurrence. Tumor staging indicated reduced life expectancy in all patients. Thirty-eight patients (82.7%) had myocardial revascularization; 8 patients (17.3%) underwent valve operations. Postoperatively, all but 2 patients were free from complications. In-hospital mortality was 4.3% (2/46). One patient died of cardiogenic shock after combined aortic and mitral valve replacement; the second patient succumbed to pulmonary embolism after reoperative coronary artery bypass grafting. Actuarial survival at 3 years was 96%, and all patients reported a satisfactory quality of life. This experience suggests that cardiac operations in selected patients with previously treated cancer are safe and offer clinical improvement at a reasonable operative risk.
Autologous pericardial flap for prevention of reentry injury in cardiac reoperations.
Cardiac injury during sternal reentry to the heart is a rare but dangerous complication of cardiac reoperations. Positioning a pericardial flap between the heart and sternum at the time of the initial operation may consistently facilitate cardiac reoperation by providing a reliable plane of dissection and by reducing adhesion formation.
Subxiphoid approach for insertion of ICDs after previous median sternotomy.
To avoid the risks both of repeat median sternotomy and of thoracotomy, the modified subxiphoid approach was adopted for insertion of implantable cardioverter-defibrillators in 10 patients who had previously undergone cardiac operations via median sternotomy. Effective implantable cardioverter-defibrillator systems were implanted in all patients. There were no operative deaths and no hemorrhagic or respiratory complications. One patient underwent repositioning of a dislodged superior vena caval electrode, and an infected generator pocket developed in 1 patient. Early extubation was routine. Two patients were observed in the coronary care unit for the first postoperative night. Postoperative pain was controlled with oral analgesic agents. The subxiphoid approach is safe and effective, and it carries a substantially lower risk of complications than other techniques, even in this high-risk group of patients. By minimizing the need for admission to the intensive care unit, invasive monitoring, and prolonged ventilatory support, by reducing surgical complications, and by shortening the hospital stay, the subxiphoid approach saved an average of $3,295 per patient.