Biomedical subjects

K Kesler

Publications and source records attributed to K Kesler.

15 recordsLinked to original sources

PubMed1999

The noninvasive prediction of cardiac mortality in men and women with known or suspected coronary artery disease. Economics of Noninvasive Diagnosis (END) Study Group.

PURPOSE: The association between myocardial perfusion imaging defects and cardiac mortality in women is undefined. We examined whether myocardial perfusion imaging predicted cardiac mortality in men and women and compared this with other variables influencing prognosis. SUBJECTS AND METHODS: Six academic institutions with high-volume nuclear cardiology laboratories consecutively studied 5,009 men aged 62 +/- 12 years (mean ISD) and 3,402 women aged 66 +/- 11 years with symptomatic known or suspected coronary artery disease undergoing exercise (n = 7,486) or pharmacologic stress (n = 925) myocardial perfusion imaging. A pretest clinical risk index was calculated from age, history of myocardial infarction, diabetes, hypertension, and hypercholesterolemia. Myocardial perfusion images were analyzed for stress-induced defects or any defect in the territories of the three major coronary arteries. RESULTS: Stress-induced perfusion defects were seen in 39% of men and 25% of women (P = 0.0001). Extensive stress-induced or fixed defects (>2 vascular territories) were less common in women than men (10% vs 19%, and 4% vs 18%, both P = 0.0001). During a mean of 2.4 +/- 1.5 years of follow-up, 143 patients died of cardiac causes. The clinical risk index and number of territories with perfusion defects were associated with cardiac mortality in women and men. In women undergoing exercise myocardial perfusion imaging, the number of abnormal territories remained the strongest correlate of mortality after adjustment for exercise variables. CONCLUSIONS: The results of myocardial perfusion imaging are important, independent predictors of survival in both women and men.

Aged↗

PubMed1998

Identification of variables needed to risk adjust outcomes of coronary interventions: evidence-based guidelines for efficient data collection.

OBJECTIVES: Our objectives were to identify and define a minimum set of variables for interventional cardiology that carried the most statistical weight for predicting adverse outcomes. Though "gaming" cannot be completely avoided, variables were to be as objective as possible and reproducible and had to be predictive of outcome in current databases. BACKGROUND: Outcomes of percutaneous coronary interventions depend on patient risk characteristics and disease severity and acuity. Comparing results of interventions has been difficult because definitions of similar variables differ in databases, and variables are not uniformly tracked. Identifying the best predictor variables and standardizing their definitions are a first step in developing a universal stratification instrument. METHODS: A list of empirically derived variables was first tested in eight cardiac databases (158,273 cases). Three end points (in-hospital death, in-hospital coronary artery bypass graft surgery, Q wave myocardial infarction) were chosen for analysis. Univariate and multivariate regression models were used to quantify the predictive value of the variable in each database. The variables were then defined by consensus by a panel of experts. RESULTS: In all databases patient demographics were similar, but disease severity varied greatly. The most powerful predictors of adverse outcome were measures of hemodynamic instability, disease severity, demographics and comorbid conditions in both univariate and multivariate analyses. CONCLUSIONS: Our analysis identified 29 variables that have the strongest statistical association with adverse outcomes after coronary interventions. These variables were also objectively defined. Incorporation of these variables into every cardiac dataset will provide uniform standards for data collected. Comparisons of outcomes among physicians, institutions and databases will therefore be more meaningful.

Adult↗

PubMed1998

Immune responses of prematurely born infants to hepatitis B vaccination: results through three years of age.

BACKGROUND: Hepatitis B vaccine is effective in infants. Preterm infants also respond but information on long term immunogenicity is limited. PURPOSE OF STUDY: To compare response of premature and full term infants to hepatitis B vaccine. METHODS: Sixty-nine prematurely born Alaska Native infants received three doses of hepatitis B vaccine beginning at discharge. Thirty-seven infants had paired serum samples drawn at approximately 1 and 3 years of life which were tested for antibody to hepatitis B surface antigen. One hundred eight infants born at full term enrolled in a separate study were used for comparison. RESULTS: Both early and late blood sample antibody to hepatitis B surface antigen titers were lower in preterm than in term infants (23.1 mIU/ml vs. 56.8 mIU/ml, early blood sample; and 0.7 mIU/ml vs. 1.32 mIU/ml, late blood sample); however, these values were not statistically different. The drop in titer over time, however, was significant in both groups as was the decrease in the percent of infants with titers > or = 10 mIU/ml (preterm infants 75.7% early specimen and 8.1% late specimen compared with term infants 87% early specimen and 15% late specimen). Both prematurity and longer interval between third vaccination and blood sample were associated with a decreased antibody titer. No infant had evidence of hepatitis B viral infection by developing antibody to hepatitis B core antigen. CONCLUSIONS: Preterm and term infants have a similar decline in antibody titers during the first 3 years, but preterm infants generally have a lower titer. The immunogenicity of the vaccine beyond 3 years and the need for revaccination in these populations requires further study.

Child, Preschool↗

PubMed1998

Prognosis by measurements of left ventricular function during exercise. Duke Noninvasive Research Working Group.

UNLABELLED: This study was performed to determine whether gated equilibrium radionuclide angiogram measurements of left ventricular function during rest and exercise add independent information to clinical and catheterization data in predicting cardiac death. METHODS AND RESULTS: The study population consisted of 863 consecutive patients undergoing exercise gated equilibrium radionuclide angiography within 90 days of cardiac catheterization with data prospectively entered into the Duke Cardiovascular Database. All patients were symptomatic, medically treated, with significant coronary artery disease and had undergone follow-up for < or = 6 yr. A univariable and multivariable Cox regression analysis was utilized to evaluate the independent power in predicting 147 (17.0%) cardiac deaths. This risk-adjusted analysis revealed that only rest and exercise ejection fraction as well as maximum workload contained independent prognostic information; the nuclear variables contributed 63% of the total information within the model. A multivariable model including exercise ejection fraction and clinical history variables provided slightly more prognostic information than the combination of cardiac catheterization and clinical data. CONCLUSION: Multigated equilibrium radionuclide angiography is a key predictor of cardiac death when compared to clinical and cardiac catheterization data in patients with symptomatic, medically treated coronary artery disease. Thus, long-term outcome for patients may be determined by utilizing this noninvasive tool even when clinical and cardiac catheterization data are also available.

Cardiac Catheterization↗

PubMed1997

Endoscopic ultrasonography, fine-needle aspiration biopsy guided by endoscopic ultrasonography, and computed tomography in the preoperative staging of non-small-cell lung cancer: a comparison study.

BACKGROUND: Current methods for detecting mediastinal lymph node involvement with non-small-cell lung cancer can be inaccurate and are often invasive and expensive. OBJECTIVE: To assess the utility of endoscopic ultrasonography, fine-needle aspiration biopsy guided by endoscopic ultrasonography, and computed tomography for the detection of metastases to the posterior mediastinal lymph nodes in non-small-cell lung cancer. DESIGN: Prospective preoperative evaluation of the diagnostic operating characteristics of these procedures. SETTING: Referral-based academic medical center. PATIENTS: 130 consecutive patients with non-small-cell lung cancer who were otherwise good surgical candidates. INTERVENTIONS: All patients had initial computed tomography of the chest; those with enlarged nodes were referred for endoscopic ultrasonography. Endoscopic ultrasonography-guided fine-needle aspiration biopsy was done on suspicious contralateral posterior mediastinal or subcarinal lymph nodes identified by ultrasonography. At surgery, lymph nodes were dissected and categorized by location and underwent histopathologic evaluation. RESULTS: 52 patients were ultimately enrolled in the study: Thirty-one had thoracotomy with mediastinal dissection, and 21 had tumors considered unresectable on the basis of preoperative evaluation. Ultrasonography without aspiration biopsy had an overall accuracy of 84% for predicting metastasis to lymph nodes; computed tomography had an accuracy of 49% (P < 0.025). Twenty-four patients had ultrasonography-guided aspiration biopsy; 14 of 24 were ineligible for surgery because cytology showed malignancy. Results of surgical pathology correlated with negative aspiration cytology results in 9 of 10 patients, the one node with false-negative results contained a 2-mm focus of cancer. The accuracy of ultrasonography-guided aspiration biopsy in diagnosing metastasis to lymph nodes was 96%; the results of this test prompted a change in management in 95% of the patients who had the procedure. CONCLUSIONS: Endoscopic ultrasonography alone or with fine-needle aspiration biopsy adds useful diagnostic information in determining metastasis to posterior mediastinal or subcarinal lymph nodes in patients with non-small-cell lung-cancer. These procedures are especially helpful in the preoperative evaluation of patients with suspicious contralateral mediastinal or "bulky" subcarinal nodes.

Biopsy, Needle↗

PubMed1997

Usefulness of serial radionuclide angiography in predicting cardiac death after coronary artery bypass grafting and comparison with clinical and cardiac catheterization data.

This investigation assesses the prognostic value of radionuclide measurements of cardiac function in patients undergoing coronary artery bypass grafting (CABG). Radionuclide angiograms during exercise and at rest were obtained in 182 patients before (< or = 30 days), early (< or = 3 months), and late (< or = 3 years) after CABG. Cox proportional hazard regression analysis was used to identify independent predictors of 44 cardiac deaths that occurred a median 12 years after bypass. Although the exercise ejection fractions before and early after CABG were significantly related to subsequent cardiac death (chi-square = 10.84, p = 0.001, and chi-square = 7.4, p = 0.006, respectively), the late postoperative exercise ejection fraction was the strongest predictor (chi-square = 13.9, p = 0.0002), contributing above and beyond clinical and catheterization data. These data document the validity of the exercise ejection fraction as an important predictor of cardiac death after CABG and suggest the potential clinical application of serial measurements of the exercise ejection fraction as an important noninvasive adjunct to postoperative evaluation of these patients.

Cardiac Catheterization↗

PubMed1996

A metaanalysis of predischarge risk stratification after acute myocardial infarction with stress electrocardiographic, myocardial perfusion, and ventricular function imaging.

We assessed the relation of abnormal predischarge non-invasive test results to outcomes in postmyocardial infarction patients. We included series published from 1980 to 1995 containing only myocardial infarction patients, enrolling most patients after 1980, testing within 6 weeks of infarction, having follow-up rates > 80%, and having 2 x 2 frequency outcome rates for test results, that were the latest of multiple reports. Sensitivity, specificity, and predictive values were calculated for test results for 1-year outcomes (cardiac death, cardiac death or reinfarction). Univariable and summary odds were calculated for test results. Reports (n = 54) included a total of 19,874 patients and were primarily retrospective (76%) and small series (35% of reports included < 5 deaths). One-year mortality ranged from 2.5% for pharmacologic stress echocardiography to 9.3% for exercise radionuclide angiography. Positive predictive values for most noninvasive risk markers were < 0.10 for cardiac death and < 0.20 for death or reinfarction. Electrocardiographic, symptomatic, and scintigraphic risk markers of ischemia (ST-segment depression, angina, a reversible defect) were less sensitive (< or = 44%) for identifying morbid and fatal outcomes than markers of left ventricular dysfunction or heart failure (exercise duration, impaired systolic blood pressure response, and peak left ventricular ejection fraction). The positive predictive value of predischarge noninvasive testing is low. Markers of left ventricular dysfunction appear to be better predictors than markers of ischemia. Limitations of the literature-small samples and widely varying event rates-impede our ability to discern the accuracy of pre-discharge noninvasive testing. More rigorous, controlled trials are required to elucidate the relative value of these tests for risk stratification.

Diagnostic Imaging↗

PubMed1996

Long-term survival benefits of coronary artery bypass grafting and percutaneous transluminal angioplasty in patients with coronary artery disease.

The purpose of this study was to evaluate long-term survival benefits of bypass surgery and angioplasty versus medical therapy in 9263 patients at Duke University Medical Center between 1984 and 1990 with coronary artery disease confirmed by cardiac catheterization to involve one, two, or three vessels. Clinical data were prospectively entered into an established cardiovascular database, and annual follow-up was 97% complete for a mean interval of 5.3 years and a maximal interval of 10 years. Outcomes were analyzed with the Coronary Artery Surgery Study "method A" to define patient groups treated by medicine (n = 2449), angioplasty (n = 2924), or bypass surgery (n = 3890). Differences among treatment groups in baseline characteristics were adjusted by Cox proportional hazard models. The anatomic severity of coronary artery stenosis best defined survival benefit from bypass surgery and angioplasty versus medical treatment. One or both interventional treatments provided better long-term survival than did medical treatment for all levels of disease severity. All patients with single-vessel disease, except those with at least 95% proximal left anterior descending stenosis, benefited from angioplasty versus bypass. All patients with three-vessel disease and those two-vessel patients with > or = 95% proximal left anterior descending stenosis benefited from bypass surgery versus angioplasty. All other patients with two-vessel disease and those with > or = 95% proximal left anterior descending stenosis only had similar survival with either interventional treatment. The absolute survival benefit was greatest for patients with severe three-vessel disease treated with bypass surgery.

Angioplasty, Balloon, Coronary↗

PubMed1995

Mediastinitis after coronary artery bypass graft surgery. Risk factors and long-term survival.

BACKGROUND: Mediastinitis is a severe complication of coronary artery bypass graft surgery (CABG). The purpose of the present study was to determine preoperative and intraoperative variables that predict mediastinitis and to determine the impact of this complication on long-term survival. METHODS AND RESULTS: Data on 20 preoperative and intraoperative variables were collected prospectively on 6459 consecutive patients who underwent CABG between January 1987 and January 1994. Eighty-three patients (1.3%) developed mediastinitis postoperatively, and a total of 24 patients (29%) died. Multivariate analysis identified 4 of the 20 variables as highly significant independent predictors for the development of mediastinitis: obesity (P = .0002), New York Heart Association congestive heart failure class (P = .002), previous heart surgery (P = .008), and duration of cardiopulmonary bypass (P = .05). A comprehensive review of the literature identified 13 other studies that evaluated 48 factors as predictors of mediastinitis; these data were critically analyzed and compared with the results from this series. In this series, postoperative interval mortality during the first 90 days after surgery for the patients with mediastinitis was 11.8% compared with 5.5% for the patients without mediastinitis. Interval mortality between 1 and 2 years after surgery remained high for the mediastinitis group (8.1%) relative to the nonmediastinitis group (2.3%). These differences were not eliminated by adjusting for important variables that influenced late survival in this population. CONCLUSIONS: The present study and a review of the literature suggest that obesity and duration of surgery are the most important predictors of mediastinitis. Furthermore, although the early increase in mortality has been well described, the present study documents for the first time that mediastinitis has a significant negative influence on long-term survival independent of the patient's preoperative condition.

Cardiac Surgical Procedures↗

PubMed1991

Complement activation during prolonged extracorporeal membrane oxygenation.

Short-term cardiopulmonary bypass activates the complement system, possibly resulting in pulmonary dysfunction from granulocyte aggregation and pulmonary endothelial damage. These effects may be inhibited by steroids. Prolonged extracorporeal membrane oxygenation (ECMO) is used for newborn respiratory failure, but the effects of ECMO on complement activation are unknown. Twenty-one newborn infants with respiratory failure treated with ECMO were randomly assigned to group I (control, no steroids) or group II (30 mg/kg intravenous methylprednisolone before ECMO). Depletion assays of C3 and C5 were performed in each group at intervals before and during ECMO (declining values indicate complement activation). The groups were compared for complement levels, survival, time on ECMO and on the ventilator, and total hospitalization time. Steroids significantly shortened the time on ECMO and time on the ventilator after ECMO but did not affect survival or total hospitalization time. Steroids also enhanced activation of C3 and C5. Complement activation occurs during ECMO. Steroid administration paradoxically causes earlier complement activation but shortens ECMO and ventilator times. Complement activation during ECMO is of questionable significance. The benefits of steroids during ECMO may be mediated through other mechanisms.

Birth Weight↗

PubMed1984

Endothelial seeding of Dacron and polytetrafluoroethylene grafts: the cellular events of healing.

To detect cellular differences in the healing of polytetrafluoroethylene (e-PTFE) and Dacron grafts up to 7 months after implantation, we studied 108 aortic graft interpositions in dogs. Each prosthesis was alternately prepared by endothelial seeding or by an unseeded control method. The grafts were perfusion fixed and studied with light, scanning, and transmission electron microscopy at intervals from before to 221 days after implantation. Seeding resulted in the development of an extensive endothelial flow surface in two out of three of the e-PTFE and none out of four of the Dacron grafts by 10 days after implantation (p = 0.053). After 30 days a microfibrillar subendothelial matrix ranging from 5 to 11 mu formed in all but three grafts with endothelial coverage. The inner capsule of mature Dacron grafts was significantly thicker (169 +/- 143 mu) than in e-PTFE grafts (22 +/- 32 mu; p = 0.002). Seeded and unseeded Dacron grafts had predominantly fibroblasts in the outer capsule of the graft by 10 days. Surface endothelium, vasa vasorum, fibroblasts, and myointimal cells appeared in the inner capsule between 10 and 30 days after implantation. In Dacron grafts, fibroblasts and myointimal cells predominated in the inner capsule at 30 days, with smooth muscle cells not being definitely identifiable until after 150 days. Neither fibroblasts nor myointimal cells were common (present but sparse in one of four e-PTFE grafts) at 30 days, and transmural vasa vasorum were never seen. The seeded endothelial cells migrated rapidly from the sites of initial adhesion near the e-PTFE onto the flow surface. Only one of four of the unseeded e-PTFE grafts had surface endothelium after 30 days, and only moderate coverage developed during 180 days. We conclude that endothelial healing is more rapid in seeded e-PTFE grafts than in seeded Dacron grafts and occurs by a different mechanism.

Animals↗

PubMed1983

Squamous carcinoma of the external ear.

The medical records of 486 patients with pathologically proved squamous carcinoma of the skin of the external ear were analyzed. It is a disease of elderly white men, and the helix is the most common site of origin. Well-differentiated squamous carcinoma is the most frequent histologic variant. Ninety-five percent of our patients were treated surgically with above-clavical control in 87 percent and 28 percent survival. The low survival rate was related to the old age of the patients who frequently died of intercurrent disease and second cancers. A 12 percent incidence of nodal metastases is comparable with the incidence reported in other series. Aggressive surgical ablation and the selected use of adjunctive postoperative irradiation appear justified in those patients with locally invasive tumors, multiple nodal metastases, and extracapsular invasion.

Adolescent↗

PubMedDate not supplied

Intracardiac echocardiography-guided biopsy of intracardiac masses.

A 69-year-old man diagnosed with lung cancer had a transesophageal echocardiogram performed because of suspicion of intramyocardial tumor. The transesophageal echocardiogram confirmed the presence of both a right and left atrial mass. The lung cancer was believed to be potentially resectable if this mass did not represent tumor; therefore, biopsy of the intracardiac mass was requested. Intracardiac ultrasound was used to guide the biopsy procedure. Using intracardiac ultrasound guidance, a successful biopsy was performed that revealed the presence of tumor cells.

Aged↗

PubMedDate not supplied

Susceptibility to retinopathy of prematurity in Alaskan Natives.

Threshold retinopathy of prematurity occurred in 11 of 34 Alaskan natives compared with 10 of 93 non-natives. Natives constitute 16% of the state population. This significant Alaskan native preponderance was not explained by differences in prenatal or intensive care unit morbidity except that the intervals from birth to extubation and birth to cryotherapy were shorter for natives.

Alaska↗

PubMedDate not supplied

Increasing survival of extremely low birthweight infants in Alaska.

The survival and characteristics of extremely premature infants with a birthweight between 500 and 750 grams, who were treated at Providence Hospital newborn intensive care unit, were reviewed over the years 1987 to 1989. Forty infants were admitted and treated. Survival increased from 21 percent in 1987, 47 percent in 1988 to 82 percent in 1989. Changes in perinatal and neonatal factors over the three years were reviewed and comparisons between survivors and non-survivors were analyzed. Stepwise regression analysis revealed significant increases in the incidence of chorioamnionitis and birthweight over the period. Increased survival was noted even when infants from 1989, who received artificial surfactant, were excluded (survival increased from 21 percent in 1987 to 75 percent in 1989). Recent literature on extremely low birthweight infants, including neurodevelopmental outcome, is reviewed. Survival of extremely low birthweight infants in Alaska is increasing because of multiple changes in obstetrical and pediatric practices.

Alaska↗