Secular trends in nosocomial bloodstream infections in a 55-bed cardiothoracic intensive care unit

BACKGROUND

Although bloodstream infections (BSIs) occur more frequently in intensive care unit patients than in ward patients, most studies of nosocomial BSIs in critically ill patients have not distinguished between intensive care unit populations beyond surgical, medical, and pediatric patients.

METHODS

The primary objective of this study was to characterize the secular trends in rates of nosocomial BSIs for all pathogens among patients admitted to a busy cardiothoracic intensive care unit in a single tertiary care institution between January 1986 and December 1995. Patients with nosocomial BSIs were identified through continual prospective surveillance.

RESULTS

A total of 40,207 patients were admitted to the cardiothoracic intensive care unit during the 10-year study period, and 804 episodes of nosocomial BSIs among 681 patients were identified. The mean crude BSI infection rate was 6.0 per 1,000 patient-care days and increased linearly during the study period (range, 4.4 to 8.1 per 1000 patient-care days), and approached statistical significance (p value = 0.07). The most common organisms causing BSIs were Staphylococcus aureus (12%), coagulase-negative staphylococci (11%), Candida albicans (11%), Pseudomonas aeruginosa (10%), and Enterococci (9%). The leading sources of nosocomial BSIs were primary BSIs (33%), intravascular devices (27%), lower respiratory tract infections (17%), and surgical wound infections (12%). The etiologic fraction or the proportion of deaths in cardiothoracic intensive care unit patients with BSIs was 15-fold higher than those patients without BSIs (37% versus 2.5%, p < 0.001).

CONCLUSIONS

Rates of nosocomial BSIs among patients in our cardiothoracic intensive care unit have increased linearly during the past decade and patients with nosocomial BSIs have an increased risk of in hospital mortality.

Early bloodstream infection after cardiopulmonary bypass: frequency rate, risk factors, and implications

OBJECTIVE

To determine the incidence, predisposing factors, and outcome of early bloodstream infection after cardiopulmonary bypass.

DESIGN

A case control study.

SETTING

A 54-bed cardiac surgical intensive care in a tertiary referral center.

PATIENTS

Patients from a 30-month period with preoperative hospital stay of <48 hrs and subsequent bloodstream infection within 96 hrs of cardiopulmonary bypass were included in a case group. The control group consisted of patients who had cardiac surgery on the same day as the case group.

MEASUREMENTS AND MAIN RESULTS

Patient demographics, history of comorbidity, preoperative laboratory testing, details of surgery, transfusion requirement, inotropic infusions, hemodynamics, and arterial blood gases on admission to intensive care were compared in the two groups. Measures of outcome were duration of mechanical ventilation and intensive care stay, serum creatinine on the first postoperative day, highest creatinine and bilirubin concentrations, and hospital mortality. During the study period, 7,928 patients had cardiac surgery. Sixteen (0.2%) patients had early bloodstream infection; the control group consisted of 95 patients. Thirteen of the patients with bloodstream infection had Gram-negative bacilli on blood culture, two had Candida species, and two had Gram-positive bacteria. On multivariate logistic regression analysis, greater prevalence of preoperative pulmonary hypertension (odds ratio 9; 95% confidence interval 2 to 41.8; p = .004), diabetes (odds ratio 4.6; 95% confidence interval 1.4 to 15.8; p = .01), number of blood products transfused (odds ratio 1.09; 95% confidence interval 1.04 to 1.17; p = .005), and infusion of inotropes (odds ratio 4.7; 95% confidence interval 1.3 to 16.4; p = .02) or vasopressors (odds ratio 4.1; 95% confidence interval 1.3 to 15.6; p = .02) were associated with postoperative bloodstream infection. Early bloodstream infection was associated with significantly prolonged duration of mechanical ventilation (117.2 +/- 21.5 vs. 18 +/- 8.8 hrs; p = .0001), intensive care stay (213 +/- 27.5 vs. 53 +/- 11.3 hrs; p < .0001), greater creatinine concentrations on the first postoperative day (1.6 +/- 0.1 vs. 1.2 +/- 0.04 mg/dL; p = .0002), greater maximum creatinine concentration (2.4 +/- 0.2 vs. 1.3 +/- 0.1 mg/dL; p < .0001), and greater maximum bilirubin concentration (4.7 +/- 0.6 vs. 1.3 +/- 0.2 mg/dL; p < .0001) when compared with the control group. Five (32%) of 16 bacteremic patients died vs. none of the 95 control patients (p < .0001).

CONCLUSIONS

Early bloodstream infection after cardiac surgery is uncommon and involves predominantly Gram-negative bacteria. The risk factors associated with bloodstream infection were preoperative morbidity and more complex surgery. Bloodstream infection was associated with a significantly adverse impact on outcome after cardiac surgery.

Cognitive function 5 years after randomization to coronary angioplasty or coronary artery bypass graft surgery

BACKGROUND

Coronary bypass surgery often leads to short-term cognitive dysfunction, whereas coronary angioplasty does not. Perioperative cognitive dysfunction usually resolves, although a subgroup of surgical patients may continue to exhibit long-term cognitive dysfunction. The purpose of this study was to compare cognitive function 5 years after randomization to a strategy of either initial coronary surgery or initial angioplasty.

METHODS AND RESULTS

Five centers in the Bypass Angioplasty Revascularization Investigation participated in this ancillary study. Patients with multivessel coronary disease randomized to angioplasty or surgery were eligible at the time of their 5-year clinic visit. A battery of five measures previously shown to be sensitive to perioperative changes in cognitive function was administered, including the Logical and Figural Memory Scales from the Wechsler Memory Scale, the Digit Symbol and Digit Span subtests from the Wechsler Adult Intelligence Scale, and Part B of the Reitan Trail Making Test. The 125 study patients were generally similar to the 133 patients who were eligible but did not participate, although study participants were significantly younger (P=.003). The 64 patients randomly assigned to angioplasty had baseline characteristics similar to those of 61 patients randomly assigned to surgery. Cognitive function scores were not significantly different between angioplasty or surgery patients in an intention-to-treat analysis (P=.57). There also was no difference in cognitive function scores when the data were analyzed according to whether the patient had ever undergone bypass surgery (P=.59).

CONCLUSIONS

Long-term cognitive function is similar after coronary bypass surgery and coronary angioplasty in the majority of patients.

Early onset of acute pulmonary dysfunction after cardiovascular surgery: risk factors and clinical outcome

OBJECTIVE

To define the incidence, risk factors, and clinical outcome of early pulmonary dysfunction after cardiovascular surgery for adults.

STUDY

Inception cohort.

SETTING

Adult cardiovascular intensive care unit (ICU).

PATIENTS

All adult admissions after cardiovascular surgery without preoperative pulmonary parenchyma or vascular disease over a period of 12 consecutive months.

INTERVENTION

Collection of data on demographics, preoperative organ insufficiency, emergency surgery, type of surgical procedure, cardiopulmonary bypass time, transfusion of blood products, postoperative arterial blood gases, and systemic hemodynamics on admission to the cardiovascular ICU.

MEASUREMENTS AND MAIN RESULTS

Early postoperative pulmonary dysfunction was defined by mechanical ventilation with a PaO2/FIO2 ratio of < or = 150 torr (< or = 20 kPa) and chest radiography on admission to the cardiovascular ICU. Secondary outcome included postoperative renal and neurologic dysfunction, nosocomial infections, length of mechanical ventilation, hospitalization, and death. A total of 3,122 patients were evaluated and 1,461 patients satisfied the entry criteria of the study. Early postoperative pulmonary dysfunction was present in 180 (12%) patients on admission to the cardiovascular ICU. Preoperative variables: age of > or = 75 yrs (odds ratio 1.69, 95% confidence interval [CI] 1.06 to 2.65), body mass index of > or = 30 kg/m2 (odds ratio 1.60, 95% CI 1.09 to 2.32), mean pulmonary arterial pressure of > or = 20 mm Hg (odds ratio 1.60, 95% CI 1.13 to 2.28), stroke volume index of < or = 30 mL/m2 (odds ratio 1.57, 95% CI 1.08 to 2.26), serum albumin (odds ratio 0.71, 95% CI 0.49 to 0.97), history of cerebral vascular disease (odds ratio 1.81; 95% CI 1.08 to 2.96); operative variables: emergency surgery (odds ratio 2.12, 95% CI 1.01 to 4.51), total cardiopulmonary bypass time of > or = 140 mins (odds ratio 1.54, 95% CI 1.0 to 2.34); and postoperative variables (on admission to cardiovascular ICU): hematocrit of > or = 30% (odds ratio 2.46, 95% CI 1.71 to 3.56), systemic mean arterial pressure of > or = 90 mm Hg (odds ratio 1.67, 95% CI 1.13 to 2.42), and cardiac index of > or = 3.0 L/min/m2 (odds ratio 2.09, 95% CI 1.44 to 3.01) were predictors of early postoperative pulmonary dysfunction. Pulmonary dysfunction was associated with a postoperative increase of serum creatinine (1.36 +/- 0.4 vs. 1.24 +/- 0.4 mg/dL, p < .02), neurologic complications (3% vs. 1.6%, p < .001), nosocomial infections (3% vs. 1.6%, p < .001), prolonged mechanical ventilation (2.2 +/- 5.9 vs. 1.7 +/- 5.6 days, p < .001), length of stay in the cardiovascular ICU (4.4 +/- 12.2 vs. 2.6 +/- 6.2 days, p < .001) and hospital (14.8 +/- 13.1 vs. 10.5 +/- 8.0 days, p < .001), and death (4.4% vs. 1.6%, p < .001).

CONCLUSIONS

The incidence of early postoperative pulmonary dysfunction is uncommon; however, once developed, it is associated with increased morbidity and mortality after cardiovascular surgery. Advanced age, large body mass index, preoperative increased pulmonary arterial pressure, low stroke volume index, hypoalbuminemia, history of cerebral vascular disease, emergency surgery, and prolonged cardiopulmonary bypass time are risk factors for early onset of severe pulmonary dysfunction after surgery. Postoperative hematocrit and systemic hemodynamics suggest that early postoperative pulmonary dysfunction can be a component of a generalized inflammatory reaction to cardiovascular surgery.

Role of echocardiography in evaluation of patients with Staphylococcus aureus bacteremia: experience in 103 patients

OBJECTIVES

The purpose of this prospective study was to examine the role of echocardiography in patients with Staphylococcus aureus bacteremia (SAB).

BACKGROUND

The reported incidence of infective endocarditis (IE) among patients with SAB varies widely. Distinguishing patients with uncomplicated bacteremia from those with IE is therapeutically and prognostically important, but often difficult.

METHODS

One hundred-three consecutive patients undergoing both transthoracic (TTE) echocardiography and transesophageal (TEE) echocardiography were prospectively evaluated. All patients presented with fever and > or = 1 positive blood culture and were followed up for 12 weeks.

RESULTS

Although predisposing heart disease was present in 42 patients (41%), clinical evidence of infective endocarditis (IE) was rare (7%). TTE revealed anatomic abnormalities in 33 patients, but vegetations in only 7 (7%), and was considered indeterminate in 19 (18%). TEE identified vegetations in 22 patients (aortic valve in 5, mitral valve in 9, tricuspid valve in 4, catheter in 2 and pacemaker in 2, abscesses in 2, valve perforation in 1 and new severe regurgitation in 1; 26 total [25%]). Using Duke criteria for the diagnosis of IE, definite IE was present in 26 patients (25%). Clinical findings and predisposing heart disease did not distinguish between patients with and without IE. The sensitivity of TTE for detecting IE was 32%, and the specificity was 100%. The addition of TEE increased the sensitivity to 100%, but resulted in one false positive result (specificity 99%). TEE detected evidence of IE in 19% of patients with a negative TTE and 21% of patients with an indeterminate TTE. At follow-up, cure of staphylococcal infection occurred in a similar percentage of patients with and without IE (77% and 75%, respectively). However, death due to sepsis was significantly more likely among patients with IE (4 of 26 [15%]) than among those without IE (2 of 77 [3%]) (p = 0.03).

CONCLUSIONS

Our results suggest that IE is common among patients admitted to the hospital with SAB and is associated with an increased risk of death due to sepsis. TEE is essential to establish the diagnosis and to detect associated complications. Therefore, the test should be considered part of the early evaluation of patients with SAB.

Improvement in inducible ischemia during dobutamine stress echocardiography after transmyocardial laser revascularization in patients with refractory angina pectoris

OBJECTIVES

The purpose of this ongoing study is to determine whether transmyocardial laser revascularization (TMLR) can lessen inducible ischemia and improve contractile reserve in patients with refractory angina pectoris.

BACKGROUND

TMLR is an emerging surgical technique for the treatment of myocardial ischemia and angina pectoris not amenable to conventional percutaneous or surgical revascularization. Objective data documentating a reduction in ischemia during noninvasive stress testing after TMLR are rare.

METHODS

Fifteen patients with severe coronary artery disease unsuitable for treatment with standard revascularization techniques were studied with dobutamine stress echocardiography (DSE) before TMLR. Of the 12 patients who underwent TMLR, DSE was repeated at 3 months postoperatively in 11 patients and at 6 months in 9 patients. Stress echocardiograms were analyzed for inducible ischemia, with calculation of the wall motion score index (WMSI). Heart rate and dobutamine dose achieved at peak stress were also assessed as indexes of stress tolerance.

RESULTS

Compared with that before TMLR, wall motion at rest for all myocardial segments did not change significantly after TMLR, although there was a mild improvement in the WMSI of the lased myocardial regions ([mean +/- SD] 1.64 +/- 0.34 after vs. 1.78 +/- 0.34 before TMLR, p < 0.05). Overall WMSI at peak stress improved markedly after TMLR (1.70 +/- 0.30 after vs. 2.06 +/- 0.31 before TMLR, p < 0.002), with the improvement in WMSI limited to the lased segments only (1.47 +/- 0.31 after vs. 2.15 +/- 0.34 before TMLR, p < 0.0004). The improvement in WMSI with stress resulted primarily from a decrease in the percentage of ischemic segments (47% before vs. 23% after TMLR, p < 0.0008), with no change in the percentage of infarcted segments (23% before vs. 26% after TMLR). Heart rate (83 +/- 5 beats/min before vs. 102 +/- 21 beats/min after TMLR, p = 0.01) and dobutamine infusion rate (26 +/- 9 micrograms/kg body weight per min before vs. 34 +/- 9 micrograms/kg per min after TMLR) achieved at peak stress also increased postoperatively, consistent with improved stress tolerance. The reduction in ischemic wall motion abnormalities and improved stress tolerance persisted at 6 months, without evidence of further improvement or deterioration of function over time.

CONCLUSIONS

TMLR performed in patients with refractory angina pectoris reduces ischemic wall motion abnormalities and improves stress-induced tolerance during dobutamine echocardiography. These beneficial effects persist up to 6 months postoperatively.

Isolation of a cDNA encoding Fasciola hepatica cathepsin L2 and functional expression in Saccharomyces cerevisiae

Cathepsin L2 is a major cysteine proteinase secreted by adult Fasciola hepatica. The enzyme differs from other reported cathepsin Ls in that it can cleave peptide substrates that contain proline in the P2 position. A cDNA was isolated from an expression library by immunoscreening with antiserum prepared against purified native cathepsin L2. This cDNA was sequenced and shown to encode a complete preprocathepsin L proteinase. Functionally active recombinant cathepsin L proteinase was expressed and secreted by Saccharomyces cerevisiae transformed with the cDNA. The recombinant enzyme was purified from large-scale fermentation broths using ultrafiltration and gel filtration chromatography on Sephacryl S200 HR columns. NH2-terminal amino acid sequencing showed that the cleavage point for activation of the recombinant pro-enzyme is identical to that of the F. hepatica-produced cathepsin L2. The mature active recombinant proteinase behaved similarly to the native enzyme when analysed by SDS-PAGE, immunoblotting and zymography and also cleaved peptides containing proline in the P2 position. Finally, the recombinant cathepsin L2 cleaved fibrinogen to form a fibrin clot, a property we described for F. hepatica cathepsin L2.

Preoperative therapy with amiodarone and the incidence of acute organ dysfunction after cardiac surgery

We examined the influence of preoperative therapy with amiodarone on the incidence of acute organ dysfunction after cardiac surgery in a matched case-control study. There were 220 case-control pairs matched by day of surgery, source of admission, demographic characteristics, placement of intraaortic balloon pump before surgery, repeat operations, emergency surgery, thoracic aorta surgery and other surgical procedures. History of congestive heart failure was more prevalent in the amiodarone group than in the control group before surgery (60% vs 38%, P < 0.0001). The incidence of acute organ dysfunction, duration of mechanical ventilation, and death was similar in both groups after surgery. The requirement for inotropes (26% vs 17%, P = 0.03) and vasopressors (66% vs 55%, P = 0.02) and the incidence of postoperative nosocomial infections (12% vs 6%, P = 0.04) was greater in the amiodarone group. However, the difference was not significant after adjustment for congestive heart failure (Cochran-Mantel-Haenszel test P = 0.15, P = 0.25, P = 0.16, respectively). Amiodarone did not increase the incidence of acute organ dysfunction or death after cardiac surgery. The requirement for inotropes and vasopressors and the incidence of nosocomial infections were related to the severity of the underlying cardiac disease. The practice of discontinuing amiodarone treatment before surgery to reduce the incidence of postoperative organ dysfunction should be critically reevaluated.

IMPLICATIONS

Amiodarone is often used for the treatment of life-threatening rhythm disorder. Amiodarone has been blamed for causing organ injury after cardiac surgery. In a study of 220 patients, amiodarone did not increase the risk of organ injury or death after cardiac surgery when compared with control patients. There was no evidence to support the practice of stopping amiodarone before cardiac surgery to avoid serious complications.

Dynamic three-dimensional echocardiographic reconstruction of congenital cardiac septation defects

Dynamic three-dimensional echocardiographic reconstructions of 27 cardiac septation defects were performed in 19 sedated infants and children. Using a subxiphoid rotational scanning approach, complete visualization of the entire shape and breadth of the defect was attained in 11 of 16 ventricular septal defects and 9 of 11 atrial septal defects. This technique enabled the operator to cut slices from the three-dimensional block of echocardiographic data in order to present septation defects in a region- or lesion-oriented fashion. Poor baseline two-dimensional image quality and certain small septation defects that were readily obscured by nearby structures led to inadequate three-dimensional reconstructions. The application of dynamic three-dimensional echocardiography for assessment of cardiac septation defects uniquely provided (1) the ability to present en face views of atrial and ventricular septal defects; and (2) a means by which intracardiac anatomy can be displayed in a region- and lesion-oriented fashion for interventional and surgical planning purposes.

Functional expression of Fasciola hepatica cathepsin L1 in Saccharomyces cerevisiae

A cDNA encoding the complete precursor of a Fasciola hepatica cathepsin L protease was isolated and sequenced. Functionally active enzyme was expressed and secreted by Saccharomyces cerevisiae transformed with a plasmid carrying the complete gene. Experiments with temperature-sensitive yeast mutants showed that the enzyme is trafficked through the yeast secretory pathway. Yeast transformed with a truncated gene, which lacked the pre-peptide-encoding and most of the pro-peptide-encoding sequences, did not express funtionally active enzyme. The yeast-expressed enzyme exhibited physicochemical properties in common with the native enzyme including, pH optimum for activity, stability at 37 degrees C and ability to cleave gelatin and immunoglobulin. Enzyme kinetic data showed that the native and yeast-expressed cathepsin L1 have similar specificities for substrates with hydrophobic residues in the P2 position. This is the first report of the functional expression of a cathepsin L proteinase in S. cerevisiae that did not require the use of yeast secretory signal sequences.

The relationship between the supply of cardiac catheterization laboratories, cardiologists and the use of invasive cardiac procedures in northern New England

OBJECTIVES

Utilization rates of coronary angiography and cardiac revascularization have been found to vary between areas. This study addresses the relationship between resource supply and procedure rates.

METHODS

We compared the association of per capita catheterization laboratories, per capita cardiologists and multi-provider markets (where more than one hospital offers coronary angiography services) with the utilization rates for angiography and cardiac revascularization in northern New England, USA. Administrative data were used to capture invasive cardiac procedures. Small area analyses were used to create coronary angiography service areas. Linear regression methods were used to measure associations between the resource supply and utilization rates.

RESULTS

Variation in the use of invasive cardiac procedures was strongly associated with the population-based availability of catheterization facilities and multi-provider markets and unrelated to cardiologist supply or need (as reflected in the hospitalization rates for myocardial infarction). In the multivariate model, an increase of 1 catheterization laboratory per 100,000 population was associated with an increase in the angiography rate of 1.62 per 1000 population; those service areas with multi-provider markets were associated with an additional increase in the angiography rate of 1.27 per 1000 population (R2 = 0.84, P = 0.0006). There was a moderately strong relationship between the catheterization laboratories per capita and the revascularization rates (R2 = 0.43, P = 0.029). Angiography rates were highly associated with cardiac revascularization rates: an increase in the angiography rate of 1 per 1000 population was associated with a 0.46 per 1000 increase in the cardiac revascularization rate (R2 = 0.85, P = 0.0001).

CONCLUSIONS

Our work suggests that current efforts to address variation in cardiac procedures through activities such as appropriateness criteria, guidelines and utilization review are misdirected and should be redirected towards capacity, in this case the supply of catheterization facilities.

Residential alcohol detoxification: new role for mental health nurses

This article discusses the philosophy and practice of a community-based residential detoxification service for people with alcohol problems. The service is provided on a direct-access basis and has a team of 19 nurses who are supported by a GP practice. The article highlights issues relevant to nursing in this community facility by referring to three case studies. The case studies demonstrate that this client group finds it difficult to access other forms of health and social care. The case examples emphasize both the qualitative aspects of nursing care and the decision-making involved in this type of service. The authors suggest that large populations with complex needs can be served by nursing-led services adopting a 'direct access' approach.

Clinical characteristics of preoperative hypoalbuminemia predict outcome of cardiovascular surgery

OBJECTIVE

To define the clinical characteristics and outcome of preoperative hypoalbuminemia in adult cardiovascular surgery.

STUDY

Inception cohort.

SETTING

Adult cardiovascular intensive care unit (CVICU).

PATIENTS

Admissions to CVICU between January 1 and December 31, 1993.

INTERVENTION

Preoperative hypoalbuminemia (serum albumin < or = 3.5 g/dL) was classified by the presence of malnutrition cachexia (body mass index of < or = 20 kg/m2), liver insufficiency (serum bilirubin > or = 2.0 mg/dL), history of congestive heart failure, or hypoalbuminemia alone. Demographics, chronic diseases, systemic hemodynamics, and laboratory data were obtained at preoperative and later on admission and during the stay in the CVICU.

OUTCOME MEASURES

Postoperative organ dysfunction, nosocomial infections, length of mechanical ventilation, hospitalization and death.

RESULTS

A total of 2,743 patients (91%) of 3,025 patients who were admitted to the CVICU were enrolled in the study. Preoperative hypoalbuminemia was found in 325 patients (12%): hypoalbuminemia and cachexia in 21 patients (6%), hypoalbuminemia and liver insufficiency in 26 patients (8%), hypoalbuminemia and history of congestive heart failure in 102 patients (31%), and hypoalbuminemia alone in 176 patients (54%). Clinical features of preoperative hypoalbuminemia were age > or = 75 years, female gender, left ventricular ejection fraction < or = 35%, hematocrit < or = 34%, serum creatinine > or = 1.9 mg/dL, systemic oxygen delivery < or = 350 mL/min.m2, acute stressful conditions (eg, infective endocarditis, acute myocardial infarction, or emergency surgery) and chronic obstructive pulmonary airway disease. Redo operations, combined valve and coronary artery bypass graft, mitral valve replacement, and thoracic aortic surgery were the commonest types of surgery performed in these patients. All types of hypoalbuminemia except for malnutrition cachexia increased the likelihood of postoperative organ dysfunction (cardiac, pulmonary, renal, hepatic, and neurologic), gastrointestinal bleeding, nosocomial infections, length of mechanical ventilation, stay in the CVICU, and hospital death. Cachectic hypoalbuminemia increased the requirement for postoperative parenteral nutrition and prolonged the length of stay in hospital.

CONCLUSION

Preoperative hypoalbuminemia was attributed to malnutrition cachexia, liver insufficiency or congestive heart failure in < 50% of cardiac patients undergoing cardiovascular surgery. All types of hypoalbuminemia except for malnutrition cachexia increased the likelihood of postoperative organ dysfunction, nosocomial infections, prolonged mechanical ventilation, and death. The morbidity and mortality attributed to hypoalbuminemia could be explained by the underlying clinical characteristics rather than malnutrition cachexia in cardiac patients.

Medical care costs and quality of life after randomization to coronary angioplasty or coronary bypass surgery. Bypass Angioplasty Revascularization Investigation (BARI) Investigators

BACKGROUND

Randomized trials comparing coronary angioplasty with bypass surgery in patients with multivessel coronary disease have shown no significant differences in overall rates of death and myocardial infarction. We compared quality of life, employment, and medical care costs during five years of follow-up among patients treated with angioplasty or bypass surgery.

METHODS

A total of 934 of the 1829 patients enrolled in the randomized Bypass Angioplasty Revascularization Investigation participated in this study. Detailed data on quality of life were collected annually, and economic data were collected quarterly.

RESULTS

During the first three years of follow-up, functional-status scores on the Duke Activity Status Index, which measures the ability to perform common activities of daily living, improved more in patients assigned to surgery than in those assigned to angioplasty (P<0.05). Other measures of quality of life improved equally in both groups throughout the follow-up period. Patients in the angioplasty group returned to work five weeks sooner than did patients in the surgery group (P<0.001). The initial mean cost of angioplasty was 65 percent that of surgery ($21,113 vs. $32,347, P<0.001), but after five years the total medical cost of angioplasty was 95 percent that of surgery ($56,225 vs. $58,889), a difference of $2,664 (P = 0.047). The five-year cost of angioplasty was significantly lower than that of surgery among patients with two-vessel disease ($52,930 vs. $58,498, P<0.05), but not among patients with three-vessel disease ($60,918 vs. $59,430). After five years of follow-up, surgery had an overall cost-effectiveness ratio of $26,117 per year of life added, but unacceptable ratios of $100,000 or more per year of life added could not be excluded (P=0.13). Surgery appeared particularly cost effective in treating diabetic patients because of their significantly improved survival.

CONCLUSIONS

In patients with multivessel coronary disease, coronary-artery bypass surgery is associated with a better quality of life for three years than coronary angioplasty, after the initial morbidity caused by the procedure. Coronary angioplasty has a lower five-year cost than bypass surgery only in patients with two-vessel coronary disease.

Evaluation of patterns of perfusion and metabolism in dobutamine-responsive myocardium

OBJECTIVES

We investigated the patterns of perfusion and metabolism in dysfunctional myocardium whose contractility improved with dobutamine.

BACKGROUND

Clinical studies have suggested that dobutamine echocardiography can identify hibernating myocardium, but laboratory studies suggest that reduced perfusion limits the response to dobutamine.

METHODS

Twenty-five patients with coronary disease and ventricular dysfunction underwent low (5 and 10 micrograms/kg body weight per min) and high dose (maximum of 50 micrograms/kg per min) dobutamine echocardiography and positron emission tomography (PET) using nitrogen-13 (N-13) ammonia and fluorine-18 fluorodeoxyglucose (FDG) for imaging of perfusion and metabolism. Wall motion and tracer uptake were scored in 16 left ventricular segments.

RESULTS

Perfusion and metabolism were normal in 56.4%, mildly reduced in 29.1% and mismatched (reduced perfusion, preserved FDG uptake) in 14.5% of dysfunctional segments viable on PET. Wall motion improved with dobutamine in 89 dysfunctional segments (62 at low dose, 27 only at peak dose), and 86 of these (97%) were viable on PET. Improvement in wall motion with dobutamine was more common in segments with normal perfusion and metabolism (56.5%) than in those with mildly reduced tracer uptake (28.5%, p < 0.001) and those with mismatch (32%, p = 0.03). All the segments with a biphasic response were supplied by vessels with > or = 70% stenosis, and 88% had normal perfusion and metabolism.

CONCLUSIONS

The majority of viable segments with rest dysfunction had normal perfusion and metabolism, suggesting that myocardial stunning was common. Improvement of wall motion at low and high doses of dobutamine was highly correlated with myocardial viability on PET and was more common in myocardium with normal perfusion. A biphasic response to dobutamine identified segments with normal perfusion and metabolism supplied by severely diseased vessels.

Immediate postoperative care of cardiac surgical patients

Anesthetic care of the cardiac surgery patient is a continuum, beginning with the preoperative visit and ending when the patient is ambulatory and breathing well on the postoperative floor. Anesthesiologists are well-suited to provide postoperative care because the respiratory and cardiovascular management techniques are an extension of OR management. Attention to details is as important in the ICU as in the OR and offers the opportunity to forestall or reduce morbidity.

A pilot study of prednisone in Alzheimer's disease

Preliminary to a multicenter trial, an open-label study was conducted of prednisone treatment in Alzheimer's disease. Prednisone was given at an initial dose of 10 mg (part 1) or 20 mg (part 2) and tapered over 7 weeks. There were no serious adverse events attributed to the medication, and there were no significant changes in either mean cognitive or behavioral assessment scores with treatment during either part. Serum levels of the acute phase proteins alpha-1-antichymotrypsin and C-reactive protein did not change significantly during part 1, but were suppressed by the higher dose given in part 2. Thus, a prednisone regimen with an initial dose of 20 mg is tolerable and results in suppression of the acute phase response in Alzheimer's disease.

Comparison of digital with videotape echocardiography in patients with chest pain in the emergency department

We prospectively compared digital echocardiographic images, by a minimal digital-acquisition strategy, with videotape images to determine the diagnostic utility of digital imaging in patients admitted to the emergency department with chest pain. Digital acquisition has many potential advantages for evaluating echocardiographic images, especially in the acute-care setting. It is not yet known how much the imaging study can be condensed with digital technology and still provide the necessary information needed for clinical echocardiographic diagnosis. One hundred seventeen patients with diagnoses consisting of coronary artery disease, pericardial disease, and valvular disease were studied. Overall agreement between videotape and digital recordings with regard to normal versus abnormal wall motion was 94% (p < 0.001). The wall motion score index, a semiquantitative measure of global function, also correlated well (r = 0.94). Complete concordance was noted in all patients with aortic stenosis and pericardial effusion. Digital echocardiographic imaging, by a minimal-acquisition strategy, is an accurate summary of the complete echocardiographic examination and provides the relevant diagnostic data needed for the assessment of patients with chest pain in the emergency department.

A systematic approach to echocardiographic image acquisition and three-dimensional reconstruction with a subxiphoid rotational scan

Rotational scanning from the subxiphoid position is an image acquisition technique used for reconstruction of dynamic three-dimensional echocardiographic images in infants and small children. The orientation of the heart within the three-dimensional data set is variable and dependent on the image plane at which rotational scanning was initiated. We describe an image acquisition technique that standardizes the orientation of the heart within the three-dimensional data set, thereby permitting a systematic approach to the reconstruction of three-dimensional renderings. Thirteen infants and small children with congenital heart disease were studied by this approach. Illustrative examples are provided. The average time required to derive a three-dimensional rendering was 37 +/- 9 minutes. We conclude that subxiphoid rotational scanning by a systematic approach to image acquisition and reconstruction can be applied successfully to the derivation of three-dimensional renderings of congenital cardiac defects.

The agreement between ventricular volumes and ejection fraction by transesophageal echocardiography or a combined radionuclear and thermodilution technique in patients after coronary artery surgery

OBJECTIVES

To study the reproducibility of and agreement between perioperative transesophageal echocardiographic (TEE) and radionuclide (RN) assessment of ventricular volumes and ejection fraction (EF).

DESIGN

A prospective, blinded comparison of two methods of measurement.

SETTING

A surgical intensive care unit in a university hospital.

PARTICIPANTS

Patients after coronary artery bypass surgery.

INTERVENTIONS

Left ventricular volumes and ejection fraction were simultaneously measured by radionuclide ventriculography and transesophageal echocardiography. Two sets of measurements were made in rapid succession with a third set after an interval.

RESULTS

Reproducibilities of EF and ventricular volumes by TEE and RN were similar. At each set of measurements, the bias for radionuclide EF and TEE Simpson's rule EF, 0.03 +/- 0.05, 0 +/- 0.06, -0.01 +/- 0.07, respectively, for radionuclide EF and TEE area length EF 0.01 +/- 0.05, -0.01 +/- 0.05, -0.03 +/- 0.08, respectively, were significantly less than for radionuclide EF and TEE FAC 0.07 +/- 0.05, 0.05 +/- 0.05, 0.03 +/- 0.09. Poor agreement was observed between RNTD-EDV, and both of the TEE EDV measurements.

CONCLUSION

EF measured by TEE area length and Simpson's rule method are as reproducible as TEE FAC and are more accurate estimates of RN EF. Poor agreement between methods of measuring end-diastolic volume was observed.