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Kathryn Williams

Publications and source records attributed to Kathryn Williams.

16 recordsLinked to original sources
PubMed2006

Ultrafiltration reduces blood transfusions following cardiac surgery: A meta-analysis.

BACKGROUND: Although used routinely in pediatric patients, ultrafiltration techniques that reverse hemodilution are infrequently used in adults. Data from small, unblinded clinical trials suggest that the use of ultrafiltration can reduce inflammatory mediators, improve cardiac function, and reduce hemodilution. We conducted a meta-analysis of randomized trials to evaluate the effects of ultrafiltration on blood transfusions and blood loss following adult cardiac surgery. METHODS: Medline, EMBASE, and Cochrane databases were searched and randomized controlled trials evaluating modified and/or conventional ultrafiltration, meeting pre-determined selection criteria, were obtained. Quality evaluation and data extraction were performed by two independent observers blinded to study source. Random effects models were used to determine pooled effect estimates and sources of heterogeneity were explored using meta-regression. RESULTS: One hundred and thirty two studies were screened and 10 randomized trials evaluating 1004 patients (control, n = 495; ultrafiltration, n = 509) were identified of which only two were double-blinded. The use of ultrafiltration was associated with a reduction in postoperative blood transfusions (weighted mean difference [95% CI] of -0.73 units [-1.16, -0.31]; p = 0.001). This reduction was greater in studies evaluating modified ultrafiltration. Use of ultrafiltration was also associated with reduced postoperative bleeding (-70 ml, [-118, -21]; p = 0.005), which was driven primarily by trials evaluating modified rather than conventional ultrafiltration. CONCLUSIONS: Use of ultrafiltration is associated with a significant reduction in postoperative blood transfusions as well as reduced bleeding in adults undergoing cardiac surgery. The efficacy and cost-effectiveness of ultrafiltration as a blood conservations strategy should be evaluated in a large, randomized, double-blinded study.

Adult↗
PubMed2006

What is the prognostic value of myocardial perfusion imaging using rubidium-82 positron emission tomography?

OBJECTIVES: The objective was to determine the prognostic value of rubidium-82 (82Rb) positron emission tomography (PET) myocardial perfusion imaging (MPI). BACKGROUND: 82Rb PET MPI accurately diagnoses coronary artery disease (CAD). However, there are limited data evaluating its prognostic value. METHODS: Follow-up (3.1 +/- 0.9 years) was obtained in 367 patients who underwent dipyridamole 82Rb PET MPI. Patients were divided into groups based on their summed stress score (SSS): group I, normal (<4); group II, mild (4 to 7); and group III, moderate (8 to 11) to severe (> or =12). RESULTS: There were significant differences among patients in the 3 SSS groups for hard events (cardiac death and myocardial infarction [MI]) (p < 0.001) and total cardiac events (hard events, revascularization and hospitalization) (p < 0.001). The annual hard events rates were 0.4%, 2.3%, and 7.0% in the normal, mild, and moderate-severe groups, respectively. In adjusted survival models, 82Rb PET SSS was the strongest predictor of total cardiac events and a significant predictor of hard events. Among patients referred for PET after 99mTc single-photon emission computed tomography, the annual total event rate was higher with abnormal versus normal SSS on PET (15.2% vs. 1.3%, p < 0.001). In patients with obesity, the annual total event rate was 11.1% with an abnormal scan and 1.5% with a normal scan (p < 0.001). CONCLUSIONS: This study shows that 82Rb PET MPI has significant prognostic value for predicting cardiac events, including death and MI. It also seems to have prognostic value in patients whose diagnosis remains uncertain after single-photon emission computed tomography MPI and in obese patients. The prognostic value of PET MPI may improve the management of cardiac patients.

Aged↗
PubMed2006

Reasons for escalating pacemaker implants.

Surveys of pacing practice have shown a steady increase in pacemaker implantation rates in the past 15 years, despite no major changes in United States guidelines for permanent pacing. There are no data to explain why this is occurring. In this study, records were extracted from the National Hospital Discharge Survey to investigate this. There were 3 major findings. First, age-adjusted implantation rates increased progressively over the study period from 370 per million in 1990 to 612 per million in 2002. Second, it was found that the escalating implantation rate is attributable to increasing implantation for isolated sinus node dysfunction (SND). Implantation for SND increased significantly over the study period (by 102%), whereas implantation for all other indications did not. The increasing implantation for SND is due primarily to the increasing prevalence of SND, with a lesser increase in implantation rate relative to prevalence rate. The third major finding of this study is that there has been a progressive relative and absolute increase in the dual-chamber implantation rate. In 2002, 82.8% of all initial pacemaker implantations were dual-chamber devices. Furthermore, the National Hospital Discharge Survey data indicate that the major randomized pacing trials seem to have had no impact on pacing practice in the United States. In conclusion, age-adjusted implantation rates increased progressively over the study period. This escalating implantation rate is primarily attributable to increasing implantation for SND.

Age Factors↗
PubMed2006

Frequency of peripartum cardiomyopathy.

Reports from case series have estimated the incidence of peripartum cardiomyopathy (PC) at 1 case/1,485 live births to 1 case/15,000 live births and probable mortality rates of 7% to 60%. The objective of this study was to produce the first population-based study of the incidence, mortality, and risk factors for PC. The National Hospital Discharge Survey was used. Discharge information was available for 3.6 million patient discharges from 1990 to 2002. There were an estimated 16,296 cases of PC from 1990 to 2002. During this period, there were 51,966,560 live births in the United States. Thus, the incidence of PC was 1 case/3,189 live births. There was a trend toward an increase in PC incidence during the study period, with an estimate for the years 2000 to 2002 of 1 case/2,289 live births. The in-hospital mortality rate was 1.36% (95% confidence interval 0% to 10.2%). The total mortality rate was 2.05% (95% confidence interval 0.29% to 10.8%). Patients with PC were older (mean age 29.7 vs 26.9 years), were more likely to be black (32.2% vs 15.7%), and had a higher incidence of pregnancy associated hypertensive disorders (22.5% vs 5.87%) compared with national data. In conclusion, the incidence of PC is relatively uncommon, occurring at an average frequency of 1 case/3,189 live births from 1990 to 2002. The estimated mortality of 1.36% to 2.05% (95% confidence interval 0.29% to 10.8%) is less than previously reported from most case series.

Adolescent↗
PubMed2005

Incidence, predictors, and outcomes of high-degree atrioventricular block complicating acute myocardial infarction treated with thrombolytic therapy.

BACKGROUND: In the fibrinolytic era, several studies have suggested that the rate of atrioventricular block (AVB) in the setting of acute myocardial infarction (MI) is high and is associated with increased short-term mortality. We sought to delineate predictors of AVB and determine long-term mortality of patients developing AVB in the setting of ST-segment elevation MI (STEMI) treated with thrombolytic therapy. METHODS: We combined data on patients from 4 similar studies of STEMI. We identified independent predictors of AVB and compared the 6-month and 1-year mortality rates of patients with AVB (5251) to the rates of patients without AVB (70 742). RESULTS: The incidence of AVB was 6.9%. Significant independent predictors of AVB included inferior MI, older age, worse Killip class at presentation, female sex, enrollment in the United States, current smoking, hypertension, and diabetes. Adjusted mortality was significantly higher in patients with AVB than in patients without AVB within 30 days (OR 3.2, 95% CI 2.7-3.7), 6 months (OR 1.6, 95% CI 1.5-1.8), and 1 year (OR 1.5, 95% CI 1.3-1.6). For patients with AVB and inferior MI, mortality odds ratios (ORs) were 2.2 (95% CI 1.7-2.7), 2.6 (95% CI 2.4-2.9), and 2.4 (95% CI 2.2-2.6) within 30 days, 6 months, and 1 year, respectively. For patients with AVB and anterior MI, mortality ORs were 3.0 (95% CI 2.2-4.1), 3.5 (95% CI 3.1-3.8), and 3.3 (95% CI 3.0-3.7) within 30 days, 6 months, and 1 year, respectively. CONCLUSIONS: In the thrombolytic era, AVB in the setting of STEMI is common and associated with higher mortality. Future studies should focus on determining therapies that are effective at reducing mortality rates in such patients.

Aged↗
PubMed2005

Neuroendocrine profiling of humans receiving cardiac allografts.

BACKGROUND: Several studies have investigated changes in circulating hormones and markers of cardiac status after heart transplantation in humans. As a result, plasma levels of various hormones and autocoids have been associated with cardiac allograft rejection status. However, no clear associations can be defined given the highly contradictory nature of the available literature. METHODS: In this study of 69 consecutive heart transplant patients followed for >2 years we examine the relationship between neurohumors potentially related to allograft rejection and endomyocardial biopsy grade of rejection (according to the ISHLT) and hemodynamic status. Markers assessed include brain natriuretic peptide (BNP), amino-terminal pro-BNP (N-BNP), atrial natriuretic factor (ANF), adrenomedullin, interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, troponin C and C-reactive protein. RESULTS: The highest plasma levels for most neurohumors were found shortly after surgery and showed a trend towards normalization with time. BNP and N-BNP were the only significantly elevated plasma analytes for patients with Grade 3 rejection as compared with other ISHLT grades. ANF plasma levels correlated with BNP and N-BNP in Grades 0 to 2, but not in Grade 3, suggesting that in this rejection grade the usual coordinated changes observed in BNP and ANF secretion no longer exist. Cardiac filling pressures were correlated with plasma BNP, N-BNP and ANF levels only for Grades 0 and 1. CONCLUSIONS: The timing of blood sampling after transplantation influences the level of the neurohumors measured, which may help explain the conflicting literature reports on the association between neurohumor levels and rejection grade. The significant increase in circulating levels of BNP and N-BNP observed in most cases of Grade 3 rejection occurred with no apparent relationship to post-transplantation time, which suggests a specific influence of acute rejection on BNP gene expression.

Adolescent↗
PubMed2005

Prognostic significance of dipyridamole-induced ST depression in patients with normal 82Rb PET myocardial perfusion imaging.

UNLABELLED: Recent studies have shown that vasodilator-induced ischemic electrocardiographic (ECG) changes have incremental prognostic value over normal SPECT myocardial perfusion imaging (MPI) and identify patients at higher risk for cardiac events. The prognostic value of vasodilator-induced ischemic ECG changes in the setting of normal PET MPI has yet to be determined. We sought to determine the prognostic importance of dipyridamole-induced ischemic ECG changes in patients with normal 82Rb PET myocardial perfusion images. METHODS: Between 2000 and 2003, 2,029 consecutive patients undergoing dipyridamole stress 82Rb PET at the University of Ottawa Heart Institute were evaluated. Patients with normal PET MPI and interpretable ECGs were enrolled. Electrocardiograms were assessed for ST depression or elevation and patients were categorized into those with and without dipyridamole-induced ischemic ECG changes. Images were graded using the 17-segment model. Follow-up information was obtained by telephone interview, from hospital records, or from treating physicians. All cardiac events (cardiac death, nonfatal myocardial infarction [MI], percutaneous coronary intervention, coronary artery bypass grafting, or angiography) were verified with hospital records. RESULTS: Of the 629 enrolled patients with normal PET MPI, 72 patients had dipyridamole-induced ischemic ECG changes. There was no significant difference between the 2 groups in the combined endpoint (cardiac death, nonfatal MI, and revascularization) at follow-up (mean +/- SD, 27.1 +/- 13 mo). There were no cardiac deaths in either group. One (1.4%) patient with ischemic ECG changes had a nonfatal MI (0.6% annual event rate). Two (2.8%) patients with ischemic ECG changes required revascularization compared with 11 (2.0%) in the nonischemic ECG group. CONCLUSION: Normal 82Rb PET confers an excellent prognosis regardless of dipyridamole-induced ST depression.

Dipyridamole↗
PubMed2004

Brain natriuretic peptide predicts successful cardioversion in patients with atrial fibrillation and maintenance of sinus rhythm.

BACKGROUND: Brain natriuretic peptide (BNP) is released from the heart by hemodynamically induced muscle stretch. Patients with atrial fibrillation have higher levels of BNP than those in sinus rhythm. OBJECTIVE: To assess the usefulness of BNP as a predictor of successful cardioversion in patients with persistent atrial fibrillation and subsequent maintenance of sinus rhythm. SUBJECTS AND METHODS: Twenty patients undergoing cardioversion for persistent atrial fibrillation were enrolled. BNP levels were measured before electric cardioversion, and 30 min and two weeks after cardioversion. Baseline echocardiograms and 12-lead electrocardiograms were obtained from all patients. Patients with valvular disease, previous mitral valve surgery or significant left ventricular dysfunction were excluded. RESULTS: The mean BNP level and the mean heart rate were significantly higher before cardioversion than 30 min after (197+/-132 pg/mL versus 164+/-143 pg/mL, P=0.02, and 77+/-17 beats/min versus 57+/-12 beats/min, P=0.0007, respectively). Patients who reverted back to atrial fibrillation after two weeks had a baseline BNP of 293+/-106 pg/mL, while those who remained in sinus rhythm for two weeks had a lower baseline BNP of 163+/-122 pg/mL (P=0.02). CONCLUSION: In patients with persistent atrial fibrillation, BNP levels are associated with successful cardioversion and maintenance of sinus rhythm two weeks after cardioversion.

Aged↗
PubMed2003

An analysis of the association between preoperative renal dysfunction and outcome in cardiac surgery: estimated creatinine clearance or plasma creatinine level as measures of renal function.

STUDY OBJECTIVES: Preoperative renal dysfunction is a risk factor for adverse events in cardiac surgery. This study compared creatinine clearance (ClCr), estimated from the Cockroft and Gault formula, and plasma creatinine level as predictors of outcome after cardiac surgery. DESIGN: Prospective, observational. SETTING: University hospital. PATIENTS: A total of 6,364 cardiac surgical patients. METHODS: The measured outcomes were postoperative renal failure requiring dialysis, and mortality and major morbidity. For each outcome, two multivariable risk models were developed, using either estimated ClCr as a measure of renal function, or plasma creatinine level. Risk-adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated for each outcome. Discrimination was compared using receiver operating characteristic (ROC) curves. RESULTS: For each 10 mL/min/1.73 m(2) decrement of estimated ClCr, the ORs for renal failure requiring dialysis, mortality, and major morbidity in the whole population were 1.52 (95% CI, 1.35 to 1.67), 1.27 (95% CI, 1.19 to 1.35), and 1.18 (95% CI, 1.14 to 1.21), respectively; for each 0.2 mg/dL increment of plasma creatinine, ORs were 1.20 (95% CI, 1.15 to 1.26), 1.08 (95% CI, 1.04 to 1.13), and 1.12 (95% CI, 1.09 to 1.15), respectively. The areas under the ROC curves for prediction of renal failure requiring dialysis were 0.83 with both risk models. For prediction of mortality and major morbidity, areas under the ROC curves were 0.83 and 0.72, respectively, with the models using estimated ClCr, and 0.74 and 0.65, respectively, with the models using plasma creatinine level (p < 0.001 vs estimated ClCr for both outcomes). In patients with normal plasma creatinine levels (n = 4,603), estimated ClCr remained a significant predictor of each outcome with similar ORs, but plasma creatinine level was not a predictor of any outcome. CONCLUSION: The risk-adjusted association between preoperative renal dysfunction and adverse events after cardiac surgery is stronger with estimated ClCr than with plasma creatinine level, particularly in patients with normal plasma creatinine levels. The routine preoperative estimation of ClCr may improve the identification of higher-risk cardiac surgical patients.

Aged↗
PubMed2002

Prognostic implications of abnormalities in renal function in patients with acute coronary syndromes.

BACKGROUND: Outcomes in patients with mild to moderate renal function (RF) abnormalities presenting with acute coronary syndromes (ACS) are not well defined. METHODS AND RESULTS: A convenience sample of 4 ACS trial databases including all enrolled patients was assessed to determine 30- and 180-day outcomes. The 4 trials were Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) IIb, GUSTO-III, Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT), and Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON-A). Patients were stratified into ST-segment elevation (STE) and non-ST-segment elevation (NSE) groups and by the presence or absence of abnormal RF (creatinine clearance <70 mL/min). In the STE group, 7670 of 18 621 patients (41%) had abnormal RF. In the NSE group, 8152 of 19 304 (42%) had abnormal RF. Patients with abnormal RF were older, more often female, and more likely to have adverse baseline characteristics. They had higher mortality and higher mortality/nonfatal myocardial infarction (MI) at both 30 and 180 days, regardless of ST-segment status. Creatinine clearance was independently associated with risk of mortality (hazard ratio 0.79 in the STE group and 0.81 in the NSE group) and with risk of mortality/MI (hazard ratio 0.93) in the NSE group at 180 days. CONCLUSIONS: Patients presenting with ACS frequently have abnormal RF. Abnormal RF is a marker of adverse baseline clinical characteristics and is independently associated with increased risk of death and death/MI.

Acute Disease↗
PubMedDate not supplied

Potential utility of rubidium 82 PET quantification in patients with 3-vessel coronary artery disease.

BACKGROUND: Standard perfusion imaging may underestimate the extent of disease in 3-vessel coronary atherosclerosis. This study determined whether positron emission tomography quantification of perfusion reserve by use of rubidium 82 net retention defined a greater extent of disease than the standard approach in patients with 3-vessel disease. METHODS AND RESULTS: Rb-82 net retention was quantified as an estimation of absolute perfusion at rest and with dipyridamole stress by use of dynamic positron emission tomography imaging. The percent of abnormal myocardial sectors, as compared with a normal database, for a standard and quantification approach was determined. Twenty-three patients were evaluated. Defect sizes were larger in patients with 3-vessel disease (n = 13) by use of quantification methods: 44% +/- 18% of the myocardial sectors were abnormal by use of the standard approach versus 69% +/- 24% of sectors when measured by quantification of the stress-rest perfusion difference (P =.008). In patients with single-vessel disease (n = 10), defect sizes were smaller with quantification methods. CONCLUSIONS: Quantification of Rb-82 net retention to measure the stress-rest perfusion difference in the myocardium defined a greater extent of disease than the standard approach in this group of patients with triple-vessel disease. More accurate measurement of the extent of coronary artery disease could facilitate better risk stratification and identify more high-risk patients in whom aggressive intervention is required.

Aged↗
PubMedDate not supplied

Persistent orthopnea and the prognosis of patients in the heart failure clinic.

Heart failure (HF) is a public health problem with ever-growing costs. Signs such as jugular venous pressure and third heart sound have been associated with disease prognosis. Symptoms of heart failure are frequently subjective, and their real value is often overlooked. The authors aimed to assess the relationship between orthopnea and left ventricular ejection fraction (LVEF) and hospitalization rate in patients referred to the HF clinic. One hundred fifty-three new consecutive patients referred to the HF clinic from September 2001 to July 2002 were reviewed. Information about orthopnea was available at baseline and at a 6-month to 1-year follow-up. One hundred thirty-one patients had a baseline multigated radionuclide ventriculogram scan, and 68 patients had a follow-up multigated radionuclide ventriculogram scan available. The patients were divided into groups by presence of orthopnea and compared with respect to LVEF and hospitalization rate. Patients with or without orthopnea had similar LVEFs at baseline (32%+/-17% vs. 33%+/-15%, respectively; p=NS). However, patients who were orthopnea-free at the follow-up visit had a significant LVEF improvement whereas patients with ongoing orthopnea at follow-up had no LVEF improvement (11%+/-13% vs. -1%+/-6%; p<0.001). Patients who presented with persistent orthopnea had a significantly higher rate of hospitalization (64% vs. 15.3%; p=0.0001). Persistent orthopnea in HF patients is associated with a significantly higher rate of hospitalization and with worsening or no improvement in LVEF. Patients with persistent orthopnea may require a more aggressive approach to improve their outcome. This result may help centers with limited access to LVEF measurements to better stratify HF patients' risk.

Aged↗
PubMedDate not supplied

Effect of Orlistat in obese patients with heart failure: a pilot study.

Heart failure is the leading cause of hospitalization. Obesity is increasingly common and is a major public health problem. The aim of this study is to assess whether obese patients with heart failure can benefit from losing weight via an orlistat-assisted diet. This randomized clinical trial included obese patients with ejection fractions < or =40%. Orlistat and diet counseling were compared with diet counseling alone. Twenty-one consecutive obese patients with heart failure were recruited. Significant improvement in 6-minute walk test (45.8 m; 95% confidence interval, 5.2-86.4 m; p=0.031), functional class (-0.6+/-0.5, p=0.014), weight loss (-8.55 kg; 95% confidence interval, -13.0 to -4.1 kg; p<0.001) and also significant decreases in total cholesterol (p=0.017), low-density lipoprotein cholesterol (p=0.03), and triglycerides (p=0.036) were observed in the orlistat group. Orlistat can promote significant weight loss and symptoms of relief in obese patients with heart failure, as measured by 6-minute walk test and functional capacity. The lipid profile improved. Orlistat was safe and well tolerated.

Anti-Obesity Agents↗
PubMedDate not supplied

BNP-guided therapy not better than expert's clinical assessment for beta-blocker titration in patients with heart failure.

B-type natriuretic peptide (BNP) is a cardiac neurohormone used as a noninvasive tool for diagnosing and monitoring heart failure. Beta blockers have beneficial effects in patients with heart failure as well as a direct effect on BNP plasma levels. The aim of this study is to compare the efficacy of a BNP-guided approach vs. standard care on beta-blocker titration in heart failure patients. Forty-one patients with heart failure were randomized into a clinical trial. Bisoprolol was started, and the dose was regularly up-titrated. BNP was measured monthly. The clinical group had beta-blocker dosage increased according to standard care, whereas the BNP group had beta-blocker dosage up-titrated according to plasma BNP levels plus standard care. The primary outcome was mean beta-blocker dose achieved after 3 months. BNP levels, left ventricular ejection fraction, clinical score, quality of life, and hospitalization were collected in all patients. BNP-guided up-titration of beta blocker in ambulatory patients with heart failure did not result in higher doses of beta blocker at the end of 3 months+/-SD (5.9+/-4.3 mg vs. 4.4+/-3.4 mg, p=0.22). Left ventricular ejection fraction was significantly improved in both groups by 7.3% (95% confidence interval, 4.1%-10.4%; p<0.0001). A trend toward better quality of life was seen in the BNP group.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Prevalence and clinical implications of anemia in congestive heart failure patients followed at a specialized heart function clinic.

The objective of this study was to assess the prevalence of anemia and to investigate its association with comorbidities and its impact on clinical outcomes in patients with heart failure. The association of predefined anemia, as well as the correlation of serum hemoglobin level as a continuous variable, with outcomes of emergency department visits, hospitalization, and mortality was investigated. There were fewer anemic patients in New York Heart Association classes I and II than in classes III and IV. Anemia was associated with higher rates of emergency department visits, hospital admissions, and all-cause mortality. Multivariable analysis showed that anemia is independently associated with mortality. When hemoglobin level was considered as a continuous variable, the authors noted that the mortality risk correlated with hemoglobin level disappears when hemoglobin level exceeds 140 g/L. The authors conclude that anemia has strong impacts on functional class and other clinical outcomes in patients with heart failure.

Aged↗