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Biomedical subjects

W S Browner

Publications and source records attributed to W S Browner.

At least 19 recordsLinked to original sources
PubMed1992

Calcium intake and blood pressure in elderly women.

The authors studied the relative importance of calcium intake as a correlate of blood pressure in a cross-sectional analysis of 6,517 nonblack women aged > or = 65 years from Portland, Oregon; Minneapolis, Minnesota; Baltimore, Maryland; and the Monongahela Valley near Pittsburgh, Pennsylvania, who enrolled in the Study of Osteoporotic Fractures in 1986. Dietary calcium intake was measured by using a modified food frequency questionnaire. There were weak associations between total calcium intake and blood pressure, such that each 1,000 mg/day increase in calcium intake was associated with a 1.5 mmHg decrease in systolic blood pressure (95% confidence interval -2.2 to -0.8, p < 0.0001) and a 0.5 mmHg decrease in diastolic pressure (95% confidence interval -0.8 to -0.20, p < 0.004). After adjustment for confounding variables, total calcium intake continued to have a weak inverse association only with diastolic blood pressure. The multivariate models revealed several stronger independent risk factors for blood pressure, including age, body mass index, alcohol consumption, and level of education (all p < 0.01). The small size of the inverse association between calcium intake and blood pressure limits its biological importance in this population of elderly women.

Aged↗
PubMed1992

Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transesophageal echocardiography and 12-lead electrocardiography. The Study of Perioperative Ischemia Research Group.

OBJECTIVE: Transesophageal echocardiography (TEE) and 12-lead electrocardiography (ECG) are sophisticated techniques that are increasingly being used to monitor for myocardial ischemia during noncardiac surgery. We examined whether the routine use of these techniques has incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes when compared with preoperative clinical data and intraoperative monitoring using continuous two-lead bipolar ECG. DESIGN: Cohort study. SETTING: Veterans Affairs medical center. PATIENTS: A total of 332 men undergoing noncardiac surgery who had or were at high risk for coronary artery disease. INTERVENTIONS: TEE, 12-lead ECG, and two-lead ECG were performed continuously during noncardiac surgery (47% vascular, 53% nonvascular). Monitoring results were not available to anesthesiologists or surgeons, and data were blindly analyzed after surgery. MAIN OUTCOME MEASURE: Perioperative ischemic outcomes (cardiac death, nonfatal myocardial infarction, unstable angina). RESULTS: In a subset of 285 patients who were adequately studied by all three techniques, 111 patients (39%) were identified as having intraoperative myocardial ischemia (by one or more monitoring techniques). By univariate analysis, intraoperative ischemia was associated with all perioperative cardiac outcomes, including ischemic outcomes, congestive heart failure, and ventricular tachycardia (P less than or equal to .02 for each of the three monitoring techniques). However, when monitoring results for TEE and 12-lead ECG were added to a multivariate model that included preoperative clinical data and continuous two-lead ECG results, the incremental value of TEE was small (odds ratio, 2.6; 95% confidence interval [CI], 1.2 to 5.7; P = .02) and that of 12-lead ECG was not significant (odds ratio, 1.5; 95% CI, 0.6 to 3.8). Furthermore, when the multivariate analysis was repeated with only ischemic outcomes, neither TEE nor 12-lead ECG retained significant associations (odds ratio, 2.2; 95% CI, 0.5 to 9.4, and odds ratio, 1.1; 95% CI, 0.2 to 6.1, respectively). CONCLUSION: When compared with preoperative clinical data and intraoperative monitoring using two-lead ECG, routine monitoring for myocardial ischemia with TEE or 12-lead ECG during noncardiac surgery has little incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes.

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PubMed1992

Ventricular arrhythmias in patients undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVE: To determine the incidence, clinical predictors and prognostic importance of perioperative ventricular arrhythmias. DESIGN: Prospective cohort study (Study of Perioperative Ischemia). SETTING: University-affiliated Department of Veterans Affairs Medical Center, San Francisco, Calif. SUBJECTS: A consecutive sample of 230 male patients, with known coronary artery disease (46%) or at high risk of coronary artery disease (54%), undergoing major noncardiac surgical procedures. MEASUREMENTS: We recorded cardiac rhythm throughout the preoperative (mean = 21 hours), intraoperative (mean = 6 hours), and postoperative (mean = 38 hours) periods using continuous ambulatory electrocardiographic monitoring. Adverse cardiac outcomes were noted by physicians blinded to information about arrhythmias. MAIN RESULTS: Frequent or major ventricular arrhythmias (greater than 30 ventricular ectopic beats per hour, ventricular tachycardia) occurred in 44% of our patients: 21% preoperatively, 16% intraoperatively, and 36% postoperatively. Compared with the preoperative baseline, the severity of arrhythmia increased in only 2% of patients intraoperatively but in 10% postoperatively. Preoperative ventricular arrhythmias were more common in smokers (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.2 to 15.0), those with a history of congestive heart failure (OR, 4.1; 95% CI, 1.9 to 9.0), and those with electrocardiographic evidence of myocardial ischemia (OR, 2.2; 95% CI, 1.1 to 4.7). Preoperative arrhythmias were associated with the occurrence of intraoperative and postoperative arrhythmias (OR, 7.3; 95% CI, 3.3 to 16.0, and OR, 6.4; 95% CI, 2.7 to 15.0, respectively). Nonfatal myocardial infarction or cardiac death occurred in nine men; these outcomes were not significantly more frequent in those with prior perioperative arrhythmias, albeit with wide CIs (OR, 1.6; 95% CI, 0.4 to 6.2). CONCLUSION: Almost half of all high-risk patients undergoing noncardiac surgery have frequent ventricular ectopic beats or nonsustained ventricular tachycardia. Our results suggest that these arrhythmias, when they occur without other signs or symptoms of myocardial infarction, may not require aggressive monitoring or treatment during the perioperative period.

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PubMed1992

Long-term cardiac prognosis following noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVE: To determine the long-term (2-year) cardiac prognosis of high-risk patients undergoing noncardiac surgery and to determine the predictors of long-term adverse cardiac outcome. DESIGN: Prospective cohort study. Historical, clinical, and laboratory data were collected during the in-hospital period, and at 6 months, 1 year, and 2 years following surgery. Data were analyzed using proportional hazards models. SETTING: University-affiliated Veterans Affairs medical center. POPULATION: A consecutive sample of 444 patients with or at high risk for coronary artery disease who had undergone elective noncardiac surgery and were discharged from the hospital in stable condition. MAIN OUTCOME MEASURES: Cardiac death, myocardial infarction, unstable angina, progressive angina requiring coronary artery bypass graft surgery or coronary angioplasty, and new unstable angina requiring hospitalization. RESULTS: Forty-seven patients (11%) had major cardiovascular complications during a 728-day (median) follow-up period: 24 had cardiac death; 11, nonfatal myocardial infarction; six, progressive angina requiring coronary artery bypass graft surgery or coronary angioplasty; and six, new unstable angina requiring hospitalization. Thirty percent of outcomes occurred within 6 months of surgery and 64% within 1 year. Five independent predictors of long-term outcome were identified. Three predictors reflected the preexisting chronic disease state: (1) the presence of known vascular disease (hazard ratio, 6.1; 95% confidence interval [CI], 2.5 to 15.0; P less than .0001); (2) a history of congestive heart failure (hazard ratio, 5.0; 95% CI, 2.0 to 12.0; P less than .0005); and (3) known coronary artery disease (hazard ratio, 3.7; 95% CI, 1.7 to 8.0; P less than .0007). Two predictors reflected acute postoperative ischemic events: (1) myocardial infarction/unstable angina (hazard ratio, 20; 95% CI, 7.5 to 53.0; P less than .0001) and (2) myocardial ischemia (hazard ratio, 2.2; 95% CI, 1.1 to 4.3; P less than .03). Patients surviving a postoperative in-hospital myocardial infarction had a 28-fold increase in the rate of subsequent cardiac complications within 6 months following surgery, a 15-fold increase within 1 year, and a 14-fold increase within 2 years (95% CI, 5.8 to 32; P less than .00001). Seventy percent of all long-term adverse outcomes were preceded by in-hospital postoperative ischemia that occurred at least 30 days (median, 282 days) before the long-term event. The development of congestive heart failure or ventricular tachycardia (without ischemia) during hospitalization was not associated with adverse long-term outcome. CONCLUSIONS: The incidence of long-term adverse cardiac outcomes following noncardiac surgery is substantial. At increased risk are patients with chronic cardiovascular disease; at highest risk are patients with acute perioperative ischemic events. We conclude that survivors of in-hospital perioperative ischemic events, specifically myocardial infarction, unstable angina, and postoperative ischemia, warrant more aggressive long-term follow-up and treatment than is currently practiced.

Acute Disease↗
PubMed1992

Predictors of postoperative myocardial ischemia in patients undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVE: To identify predictors of postoperative myocardial ischemia in patients scheduled to undergo major noncardiac surgery. DESIGN: Historical, clinical, laboratory, and physiological data were obtained prospectively before and during surgery to identify potential univariate predictors of postoperative myocardial ischemia, which then were entered into multivariate logistic models. Continuous two-lead electrocardiograms before, during, and after surgery were used to identify episodes of myocardial ischemia. SETTING: Department of Veterans Affairs tertiary care hospital. PATIENTS: A consecutive sample of 474 men at high risk for or with coronary artery disease who were scheduled to undergo major noncardiac surgery (95% compliance rate). MAIN OUTCOME MEASURE: Significant variables identified by multivariate logistic models that are associated with postoperative myocardial ischemia. RESULTS: Five major preoperative predictors of postoperative myocardial ischemia were identified: (1) left ventricular hypertrophy by electrocardiogram; (2) history of hypertension; (3) diabetes mellitus; (4) definite coronary artery disease; and (5) use of digoxin. The risk of postoperative myocardial ischemia increased progressively with the number of predictors present: in 22% of patients with no predictors, in 31% with one predictor, in 46% with two predictors, in 70% with three predictors, and in 77% with four predictors. CONCLUSION: Patients subgroups who are at high risk for developing postoperative myocardial ischemia and who might benefit the most from intensive Holter monitoring in the postoperative period now can be identified preoperatively.

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PubMed1992

In-hospital and long-term mortality in male veterans following noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVES: To determine the causes of and risk factors for mortality following noncardiac surgery. DESIGN: Prospective cohort study. SETTING: A university-affiliated Veterans Affairs medical center. PATIENTS: Consecutive series of 474 men between the ages of 38 and 89 years (mean age, 68 years) who were undergoing major noncardiac surgery involving general anesthesia. All subjects had known coronary artery disease or were at high risk for coronary artery disease. MEASUREMENTS AND RESULTS: During the initial hospitalization, 26 patients (5%) died, most commonly from sepsis (n = 6) or cardiac diseases (n = 6). Deaths occurred from postoperative days 2 to 69; half occurred more than 3 weeks after surgery. Multivariable analysis disclosed that a history of hypertension (odds ratio [OR] = 3.8; 95% confidence interval [CI], 1.1 to 13), a severely limited activity level (OR = 9.7; 95% CI, 2.5 to 37), and a creatinine clearance of less than 0.83 mL/s (OR = 6.8; 95% CI, 2.8 to 16) were all independently associated with an increased risk of postoperative mortality. The mortality rate in patients with two or more of these risk factors was 20%, nearly eight times higher (95% CI, 3.6 to 16) than those with one or no risk factors. An additional 82 patients died within the next 2 years; cancer, renal dysfunction, congestive heart failure, and obstructive pulmonary disease were independently associated with long-term mortality. CONCLUSIONS: Even in patients at high risk of cardiac complications following surgery, noncardiac causes of death are more common. Patients with a history of hypertension, severely limited activity, and reduced renal function appear to be at especially high risk of in-hospital mortality after noncardiac surgery.

Adult↗
PubMed1992

Risk factors for fractures of the distal forearm and proximal humerus. The Study of Osteoporotic Fractures Research Group.

The Study of Osteoporotic Fractures is a prospective cohort study begun in 1986 that includes 9,704 women aged 65 years and older from Maryland, Minnesota, Oregon, and Pennsylvania. A total of 171 women suffered fractures of the distal forearm, and 79 women had fractures of the proximal humerus during the first 2.2 years of follow-up. Most fractures at both sites occurred as a result of a fall. Low bone mineral density was a strong predictor of these fractures; comparing those in the lowest quintile of bone mineral density in the distal radius with those in the highest quintile, the rate ratio was 4.1 for fractures of the distal forearm and 7.5 for fractures of the proximal humerus. Other factors associated with an increased rate of distal forearm fracture independently of low bone mineral density included poor visual acuity, number of falls in the year before baseline, and frequent walking. Factors that appeared to be independently associated with an increased rate of fracture of the proximal humerus included a recent decline in health status, insulin-dependent diabetes mellitus, infrequent walking, and several indicators of neuromuscular weakness such as inability to stand with feet in a tandem position for more than a few seconds. These data support the hypothesis that distal forearm fractures often occur as a result of a fall in women with low bone mineral density who are relatively healthy and active and have good neuromuscular function, while fractures of the proximal humerus tend to occur as a result of a fall in women with low bone mineral density who are less healthy and less active than average and who have poor neuromuscular function.

Age Factors↗
PubMed1992

The accuracy of self-report of fractures in elderly women: evidence from a prospective study.

The authors compared self-reports of non-spine fractures in a cohort of elderly white women with radiologic reports and medical records. Subjects (n = 9,704) were recruited between 1986 and 1988 in Baltimore, Pittsburgh, Minneapolis, and Portland, Oregon. Eleven percent (95% confidence interval 9-13%) of self-reports of fracture were false-positive (radiographs were negative) and a total of 20% (18-23%) could not be confirmed (radiographs were negative, uncertain, or not available). Report by proxy respondent was more accurate than self-report. There were no confirmed fractures in the medical records of a random sample of 283 participants who did not report a fracture. The percent of false-positives varied by the site of the injury and was low for self-reported fractures of the shoulder or upper arm (5%; 1-13%), wrist (8%; 4-11%), and hip (11%; 5-19%), but was high for hand or finger (20%; 12-30%), rib (23%; 15-32%), and face or skull (33%; 17-54%). Having a college education was associated with increased accuracy, while a history of falls and self-reported osteoporosis were associated with decreased accuracy. The authors conclude that elderly women overreport fractures, but that self-report is relatively accurate for several important osteoporotic fractures, including those of the hip, wrist, and humerus. Self-report of "any" fracture, rib, distal extremity, and head fracture, and fractures in women with a tendency to fall or with osteoporosis should be verified by a radiologic diagnosis.

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PubMed1992

Predictors of smoking relapse after noncardiac surgery. Study of Perioperative Ischemia (SPI) Research Group.

OBJECTIVES: We studied 235 smokers who were admitted for major noncardiac surgery and who survived hospitalization to determine the frequency and predictors of smoking relapse 1 year after hospitalization. METHODS: We analyzed data collected prospectively from the Study of Perioperative Ischemia. We determined smoking status by self-report. RESULTS: At 12 months posthospitalization, 142 (76%) of the 186 surviving patients had resumed smoking. Significant independent predictors of relapse at 12 months were a history of alcohol abuse and a history of heavy cigarette smoking (P less than 0.01 and P less than 0.05, respectively). CONCLUSIONS: Since smokers commonly undergo surgery, the perioperative period provides a valuable window of opportunity for smoking cessation interventions designed to decrease the high rate of smoking relapse after surgery.

Analysis of Variance↗
PubMed1992

Effects of the multiple risk factor intervention trial smoking cessation program on pulmonary function. A randomized controlled trial.

To determine whether the decline in pulmonary function in smokers is modified by stop-smoking intervention, a randomized controlled study (the Multiple Risk Factor Intervention Trial) was done comparing participants in a special intervention group that included an intensive smoking cessation program with those assigned to usual care. The subjects were 6,347 middle-aged male smokers who had serial measurements of pulmonary function--principally the forced expiratory volume in 1 second (FEV1)--during 6 to 7 years of follow-up. No overall differences were detected in the rate of loss of FEV1 in the two groups. The use of beta-blockers, which had detrimental effects on FEV1, was significantly more common in the intervention group. Among nonusers of beta-blockers, heavy smokers lost FEV1 at a rate about 11 ml per year slower in the intervention group than in the control group (2P = .09) and ended the trial with an FEV1 about 90 ml higher (2P = .05). These results support the inference from observational studies that smoking cessation has a beneficial effect on pulmonary function in heavy smokers.

Adult↗
PubMed1992

Postoperative myocardial ischemia. Therapeutic trials using intensive analgesia following surgery. The Study of Perioperative Ischemia (SPI) Research Group.

Recent data suggest that postbypass and postoperative myocardial ischemia are related to adverse cardiac outcome following myocardial revascularization. Therapeutic trials to suppress postoperative ischemia are warranted. Because anesthetics can suppress a variety of physiologic responses to stress as well as myocardial ischemia intraoperatively, we examined whether use of intensive analgesia in the stressful postoperative period could decrease postoperative ischemia. In 106 patients undergoing elective myocardial revascularization, we standardized the anesthetic prior to bypass (sufentanil 5-10 micrograms/kg [induction] and 4.2-6.0 micrograms.kg-1.h-1 [infusion] supplemented with up to 0.5 mg/kg of diazepam). During bypass, patients were randomly assigned to receive either morphine sulfate (group M, n = 54, up to 2 mg/kg) or sufentanil (group S, n = 52, 1 microgram/kg and 1 microgram.kg-1.h-1). In the intensive care unit (ICU), group M received low-dose analgesia (morphine sulfate 1-10 mg intravenously every 30 min, average dose = 2.2 +/- 2.1 mg/h), while group S continued to receive intensive analgesia (infusion of sufentanil at 1 microgram.kg-1.h-1). Both groups received supplemental midazolam in the ICU (group M = 1.1 +/- 1.1 mg/h; group S = 0.6 +/- 0.6 mg/h; P = 0.01). All analgesic and sedative-hypnotic medications were discontinued at 18 hours following myocardial revascularization. Using continuous two-channel electrocardiographic (ECG) monitoring (CC5 and CM5), we documented and characterized ECG changes consistent with ischemia during the preoperative, intraoperative (pre- and postbypass), and postoperative (on- and off-treatment) periods. The total ECG monitoring time was 8,486 h, averaging 81 h per patient. During the prebypass (anesthetic control) period, groups M and S had a similar incidence, but group S episodes were more severe: maximum ST-segment change (median), S versus M: -1.8 mm versus -1.4 mm (P = 0.04). During the postbypass period, both groups had a similar incidence of ischemia, but episodes in group S were less severe: maximum ST-segment change, S versus M: -1.8 mm versus -2.7 mm (P = 0.0005). During the ICU-on-therapy period, the incidence of ischemic episodes was less in group S patients, and the severity was less: area-under-the-ST-time curve, S versus M: -21 mm.min versus -161 mm.min (P = 0.05). After discontinuation of the drug regimen in the ICU, the incidence and severity of ischemic episodes was similar. The incidence of hypotension, hypertension, and tachycardia was similar in both groups in both the intraoperative and ICU periods.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

Which fractures are associated with low appendicular bone mass in elderly women? The Study of Osteoporotic Fractures Research Group.

OBJECTIVE: To determine which types of fractures have an increased incidence in elderly women with low appendicular bone mass. DESIGN: Prospective cohort study. SETTING: Four clinical centers in the United States (Baltimore, Maryland; Minneapolis, Minnesota; Portland, Oregon; Monangehela Valley, Pennsylvania); and one coordinating center in San Francisco, California. SUBJECTS: Ambulatory, nonblack women (9704) aged 65 years or more who were recruited from population-based listings. MEASUREMENTS: We measured bone mass at the distal and proximal radius and calcaneus using single-photon absorptiometry. Fractures were verified radiographically. Associations were calculated as age-adjusted hazard ratios (with 95% Cls) per standard deviation decrease in bone mass. MAIN RESULTS: During a mean follow-up of 2.23 years, 841 nonspinal fractures occurred in 753 women. The risks for fractures of the wrist, foot, humerus, hip, rib, toe, leg, pelvis, hand, and clavicle were significantly related to reduced bone mass (P less than 0.05). These fractures represented 74% of nonspinal fractures. The overall hazard ratio for the occurrence of one or more of these fractures was 1.65 (Cl, 1.49 to 1.82) at the distal radius. In a subsample of the cohort, vertebral fractures were also related to low bone mass. Fractures of the ankle, elbow, finger, and face, however, were not associated with bone mass at any measurement site; the overall hazard ratio for these fractures was 1.12 (Cl, 0.96 to 1.30) at the distal radius. CONCLUSION: Most types of fractures have an increased incidence in elderly women with low bone mass.

Age Factors↗