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Dive into the research topics where Michele A. Hamilton is active.

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Featured researches published by Michele A. Hamilton.


The New England Journal of Medicine | 1995

Effect of Pravastatin on Outcomes after Cardiac Transplantation

J. Kobashigawa; Steven Katznelson; Hillel Laks; Jay Johnson; Lawrence A. Yeatman; Xiu Ming Wang; David Chia; Paul I. Terasaki; Alejandro Sabad; Gregory A. Cogert; Kevin D. Trosian; Michele A. Hamilton; Jaime Moriguchi; N. Kawata; Antoine Hage; Davis C. Drinkwater; Lynne Warner Stevenson

BACKGROUND Hypercholesterolemia is common after cardiac transplantation and may contribute to the development of coronary vasculopathy. Pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has been shown to be effective and safe in lowering cholesterol levels after cardiac transplantation. Cell-culture studies using inhibitors of HMG-CoA reductase have suggested an immunosuppressive effect. METHODS Early after transplantation, we randomly assigned consecutive patients to receive either pravastatin (47 patients) or no HMG-CoA reductase inhibitor (50 patients). RESULTS Twelve months after transplantation, the pravastatin group had lower mean (+/- SD) cholesterol levels than the control group (193 +/- 36 vs. 248 +/- 49 mg per deciliter, P < 0.001), less frequent cardiac rejection accompanied by hemodynamic compromise (3 vs. 14 patients, P = 0.005), better survival (94 percent vs. 78 percent, P = 0.025), and a lower incidence of coronary vasculopathy in the transplant as determined by angiography and at autopsy (3 vs. 10 patients, P = 0.049). There was no difference between the two groups in the incidence of mild or moderate episodes of cardiac rejection. In a subgroup of study patients, intracoronary ultrasound measurements at base line and one year after transplantation showed less progression in the pravastatin group in maximal intimal thickness (0.11 +/- 0.09 mm, vs. 0.23 +/- 0.16 mm in the control group; P = 0.002) and in the intimal index (0.05 +/- 0.03 vs. 0.10 +/- 0.10, P = 0.031). In a subgroup of patients, the cytotoxicity of natural killer cells was lower in the pravastatin group than in the control group (9.8 percent vs. 22.2 percent specific lysis, P = 0.014). CONCLUSIONS After cardiac transplantation, pravastatin had beneficial effects on cholesterol levels, the incidence of rejection causing hemodynamic compromise, one-year survival, and the incidence of coronary vasculopathy.


JAMA | 2005

Evaluation study of congestive heart failure and pulmonary artery catheterization effectiveness

James A. Hill; Daniel F. Pauly; Debra R. Olitsky; Stuart D. Russell; Christopher M. O'Connor; Beth Patterson; Uri Elkayam; Salman Khan; Lynne W. Stevenson; Kimberly Brooks; Lynne E. Wagoner; Ginger Conway; Todd M. Koelling; Carol Van Huysen; Joshua M. Hare; Elayne Breton; Kirkwood F. Adams; Jana M. Glotzer; Gregg C. Fonarow; Michele A. Hamilton; Julie M. Sorg; Mark H. Drazner; Shannon Hoffman; Leslie W. Miller; Judith A. Graziano; Mary Ellen Berman; Robert P. Frantz; Karen A. Hartman; Carl V. Leier; William T. Abraham

CONTEXT Pulmonary artery catheters (PACs) have been used to guide therapy in multiple settings, but recent studies have raised concerns that PACs may lead to increased mortality in hospitalized patients. OBJECTIVE To determine whether PAC use is safe and improves clinical outcomes in patients hospitalized with severe symptomatic and recurrent heart failure. DESIGN, SETTING, AND PARTICIPANTS The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) was a randomized controlled trial of 433 patients at 26 sites conducted from January 18, 2000, to November 17, 2003. Patients were assigned to receive therapy guided by clinical assessment and a PAC or clinical assessment alone. The target in both groups was resolution of clinical congestion, with additional PAC targets of a pulmonary capillary wedge pressure of 15 mm Hg and a right atrial pressure of 8 mm Hg. Medications were not specified, but inotrope use was explicitly discouraged. MAIN OUTCOME MEASURES The primary end point was days alive out of the hospital during the first 6 months, with secondary end points of exercise, quality of life, biochemical, and echocardiographic changes. RESULTS Severity of illness was reflected by the following values: average left ventricular ejection fraction, 19%; systolic blood pressure, 106 mm Hg; sodium level, 137 mEq/L; urea nitrogen, 35 mg/dL (12.40 mmol/L); and creatinine, 1.5 mg/dL (132.6 micromol/L). Therapy in both groups led to substantial reduction in symptoms, jugular venous pressure, and edema. Use of the PAC did not significantly affect the primary end point of days alive and out of the hospital during the first 6 months (133 days vs 135 days; hazard ratio [HR], 1.00 [95% confidence interval {CI}, 0.82-1.21]; P = .99), mortality (43 patients [10%] vs 38 patients [9%]; odds ratio [OR], 1.26 [95% CI, 0.78-2.03]; P = .35), or the number of days hospitalized (8.7 vs 8.3; HR, 1.04 [95% CI, 0.86-1.27]; P = .67). In-hospital adverse events were more common among patients in the PAC group (47 [21.9%] vs 25 [11.5%]; P = .04). There were no deaths related to PAC use, and no difference for in-hospital plus 30-day mortality (10 [4.7%] vs 11 [5.0%]; OR, 0.97 [95% CI, 0.38-2.22]; P = .97). Exercise and quality of life end points improved in both groups with a trend toward greater improvement with the PAC, which reached significance for the time trade-off at all time points after randomization. CONCLUSIONS Therapy to reduce volume overload during hospitalization for heart failure led to marked improvement in signs and symptoms of elevated filling pressures with or without the PAC. Addition of the PAC to careful clinical assessment increased anticipated adverse events, but did not affect overall mortality and hospitalization. Future trials should test noninvasive assessments with specific treatment strategies that could be used to better tailor therapy for both survival time and survival quality as valued by patients.


Journal of the American College of Cardiology | 2002

Anemia is associated with worse symptoms, greater impairment in functional capacity and a significant increase in mortality in patients with advanced heart failure.

Tamara B. Horwich; Gregg C. Fonarow; Michele A. Hamilton; W. Robb MacLellan; Jeff Borenstein

OBJECTIVES This study aimed to evaluate the relationship between anemia and heart failure (HF) prognosis. BACKGROUND Although it is known that chronic diseases, including HF, may be associated with anemia, the impact of hemoglobin (Hb) level on symptoms and survival in HF has not been fully defined. We analyzed a cohort of 1,061 patients with advanced HF (New York Heart Association [NYHA] functional class III or IV and left ventricular ejection fraction [LVEF] <40%) referred to a single center for evaluation and management. The Hb level was drawn at time of initial evaluation. Patients were divided into quartiles of Hb: Hb <12.3; Hb 12.3 to 13.6; Hb 13.7 to 14.8; Hb >14.8 g/dl. RESULTS Mean Hb was 13.6, and values ranged from 7.1 to 19.0 g/dl. The Hb groups were similar in age, medication profile, LVEF, hypertension, diabetes, smoking status and serum sodium. Lower Hb was associated with an impaired hemodynamic profile, higher blood urea nitrogen and creatinine, and lower albumin, total cholesterol and body mass index. Patients in the lower Hb quartiles were more likely to be NYHA functional class IV (p < 0.0001) and have lower peak oxygen consumption (PKVO(2)) (p < 0.0001). Survival at one year was higher with increased Hb quartile (55.6%, 63.9%, 71.4% and 74.4% for quartiles 1, 2, 3 and 4, respectively). On multivariate analysis adjusting for known HF prognostic factors, low Hb proved to be an independent predictor of mortality (relative risk 1.131, confidence interval 1.045 to 1.224 for each decrease of 1 g/dl). CONCLUSIONS In chronic HF, relatively mild degrees of anemia are associated with worsened symptoms, functional status and survival.


Journal of the American College of Cardiology | 2001

The relationship between obesity and mortality in patients with heart failure.

Tamara B. Horwich; Gregg C. Fonarow; Michele A. Hamilton; W. Robb MacLellan; Mary A. Woo; Jan H. Tillisch

OBJECTIVES The study aimed to evaluate the role of obesity in the prognosis of patients with heart failure (HF). BACKGROUND Previous reports link obesity to the development of HF. However, the impact of obesity in patients with established HF has not been studied. METHODS We analyzed 1,203 patients with advanced HF followed in a comprehensive HF management program. The patients were subclassified into categories of body mass index (BMI) defined as: underweight BMI <20.7 (n = 164), recommended BMI 20.7 to 27.7 (n = 692), overweight BMI 27.8 to 31 (n = 168) and obese BMI >31 (n = 179). This sample size allows the detection of small effects (0.02), with a power of 0.80 and an alpha level of 0.05 for comparing one-year survival between BMI groups. RESULTS The four BMI groups had similar profiles in terms of ejection fraction (mean 0.22), sodium, creatinine and smoking. The obese and overweight groups had significantly higher rates of hypertension and diabetes, as well as higher levels of cholesterol, triglycerides and low density lipoprotein cholesterol. The four BMI groups had similar survival rates. Ejection fraction, HF etiology and angiotensin-converting enzyme inhibitor use predicted survival on univariate analysis (p < 0.01), although BMI did not. On multivariate analysis, cardiopulmonary exercise tests, pulmonary capillary wedge pressure and serum sodium were strong predictors of survival (p < 0.05). Higher BMI was not a risk factor for increased mortality, but was associated with a trend toward improved survival. CONCLUSIONS In a large cohort of patients with advanced HF of multiple etiologies, obesity is not associated with increased mortality and may confer a more favorable prognosis. Further studies need to delineate whether weight loss promotion in medically optimized patients with HF is a worthwhile therapeutic goal.


Journal of the American College of Cardiology | 1997

Impact of a comprehensive heart failure management program on hospital readmission and functional status of patients with advanced heart failure.

Gregg C. Fonarow; Lynne Warner Stevenson; Julie A. Walden; Nancy Livingston; Anthony Steimle; Michele A. Hamilton; Jaime Moriguchi; Jan H. Tillisch; Mary A. Woo

OBJECTIVES To assess the impact of a comprehensive heart failure management program, functional status, hospital readmission rate and estimated hospital costs were determined and compared for the 6 months before and the 6 months after referral. BACKGROUND The course of advanced heart failure is characterized by progressive clinical deterioration reflected in frequent hospital admissions, which comprise the major financial cost. METHODS Over a 3-year period, 214 patients were accepted for heart transplantation and discharged after evaluation, which included adjustments in medical therapy and intensive patient education. Patients were in New York Heart Association functional class III or IV (94 and 120 patients, respectively), with a mean left ventricular ejection fraction of 0.21, peak oxygen consumption of 11 ml/kg per min and a total of 429 hospital admissions in the previous 6 months (average 2.0 per patient). Changes in the medical regimen included a 98% increase in angiotensin-converting enzyme inhibitor dose and a flexible diuretic regimen after 4.2-liter net diuresis, with counseling also regarding diet and progressive exercise. RESULTS During the 6 months after referral, there were only 63 hospital readmissions (85% reduction), with 0.29/patient (p < 0.0001). Functional status improved as assessed by functional class (p < 0.0001) and peak oxygen consumption (15.2 vs. 11.0 ml/kg per min, p < 0.001). The same results were seen after excluding the 35 patients without full 6-month follow-up (9 deaths, 14 urgent transplant procedures during hospital readmission, 12 elective transplant procedures from home); 34 hospital admissions occurred after referral, compared with 344 before referral. Even when adding in the initial hospital admission after referral for these 179 patients, there was a 35% decrease in total hospital admissions in the 6-month period. The estimated savings in hospital readmission costs after subtracting the initial hospital costs for management was


American Journal of Cardiology | 1990

Importance of hemodynamic response to therapy in predicting survival with ejection fraction ≤20% secondary to ischemic or nonischemic dilated cardiomyopathy

Lynne Warner Stevenson; Jan H. Tillisch; Michele A. Hamilton; Michael Luu; Catherine Chelimsky-Fallick; Jaime Moriguchi; J. Kobashigawa; Julie A. Walden

9,800 per patient. CONCLUSIONS Comprehensive heart failure management led to improved functional status and an 85% decrease in the hospital admission rate for transplant candidates discharged after evaluation. The potential to reduce both symptoms and costs suggests that referral to a heart failure program may be appropriate not only for potential heart transplantation, but also for medical management of persistent functional class III and IV heart failure.


Journal of the American College of Cardiology | 1995

Improving survival for patients with advanced heart failure : a study of 737 consecutive patients

William G. Stevenson; Lynne Warner Stevenson; Holly R. Middlekauff; Gregg C. Fonarow; Michele A. Hamilton; Mary A. Woo; Leslie A. Saxon; Paul D. Natterson; Anthony Steimle; Julie A. Walden; Jan H. Tillisch

To identify patients with left ventricular ejection fractions less than 20% who are likely to survive on tailored medical therapy after referral to transplantation, this study of 152 patients addressed the hypotheses that (1) severely elevated filling pressures initially measured at referral would not necessarily predict poor outcome, (2) survival would be best when low pulmonary wedge pressures could be achieved with therapy tailored for hemodynamic goals, and (3) coronary artery disease would be an independent risk factor for early mortality. Despite an average initial ejection fraction of 0.15, cardiac index of 2.0 liters/min/m2 and pulmonary artery wedge pressure of 28 mm Hg, the actuarial survival with tailored therapy was 63% at 1 year, with 34 of 41 (83%) deaths occurring suddenly. Survival was not related to initial filling pressure elevation, but was best predicted by the pulmonary artery wedge pressures during therapy; patients achieving pressure of less than or equal to 16 mm Hg had 1-year survival of 83 vs 38% (p = 0.0001). The other independent predictors were serum sodium and coronary artery disease. Patients with high filling pressures during therapy and coronary artery disease had 21% survival at 1 year. Survival after referral to transplantation with an ejection fraction less than or equal to 20% is better than previously described. Patients in whom left ventricular filling pressures cannot be adequately reduced by tailored therapy, particularly if coronary artery disease is present, should be considered for early transplantation.


The New England Journal of Medicine | 1999

A Controlled Trial of Exercise Rehabilitation after Heart Transplantation

J. Kobashigawa; David A. Leaf; Nancy Y. Lee; Michael P. Gleeson; HongHu Liu; Michele A. Hamilton; Jaime Moriguchi; N. Kawata; K. Einhorn; Elise Herlihy; Hillel Laks

OBJECTIVES This study sought to determine whether survival and risk of sudden death have improved for patients with advanced heart failure referred for consideration for heart transplantation as advances in medical therapy were systematically implemented over an 8-year period. BACKGROUND Recent survival trials in patients with mild to moderate heart failure and patients after a myocardial infarction have shown that angiotensin-converting enzyme inhibitors are beneficial, type I antiarrhythmic drugs can be detrimental, and amiodarone may be beneficial in some groups. The impact of advances in therapy may be enhanced or blunted when applied to severe heart failure. METHODS One-year mortality and sudden death were determined in relation to time, baseline variables and therapeutics for 737 consecutive patients referred for heart transplantation and discharged home on medical therapy from 1986 to 1988, 1989 to 1990 and 1991 to 1993. Medical care was directed by a single team of physicians with policies established by consensus. From 1986 to 1990, the hydralazine/isosorbide dinitrate combination or angiotensin-converting enzyme inhibitors were the initial vasodilators, and class I antiarrhythmic drugs were allowed. After 1990, captopril was the initial vasodilator, given to 86% of patients compared with 46% of patients before 1989. After mid-1989, class I agents were routinely withdrawn, and amiodarone was used for frequent ventricular ectopic beats or atrial fibrillation (53% of patients after 1990 vs. 10% before 1989). RESULTS The total 1-year mortality rate decreased from 33% before 1989 to 16% after 1990 (p = 0.0001), and sudden death decreased from 20% to 8% (p = 0.0006). Adjusted for clinical and hemodynamic variables in multivariate proportional hazards models, total mortality and sudden death were lower after 1990. CONCLUSIONS The large reduction in mortality, particularly in sudden death, from advanced heart failure since 1990 may reflect an enhanced impact of therapeutic advances shown in large randomized trials when they are incorporated into a comprehensive approach in this population. This improved survival supports the growing practice of maintaining potential heart transplant candidates on optimal medical therapy until clinical decompensation mandates transplantation.


Journal of the American College of Cardiology | 1990

Altered thyroid hormone metabolism in advanced heart failure

Michele A. Hamilton; Lynne Warner Stevenson; Michael Luu; Julie A. Walden

BACKGROUND In patients who have received a cardiac transplant, the denervated donor heart responds abnormally to exercise and exercise tolerance is reduced. The role of physical exercise in the treatment of patients who have undergone cardiac transplantation has not been determined. We assessed the effects of training on the capacity for exercise early after cardiac transplantation. METHODS Twenty-seven patients who were discharged within two weeks after receiving a heart transplant were randomly assigned to participate in a six-month structured cardiac-rehabilitation program (exercise group, 14 patients) or to undergo unstructured therapy at home (control group, 13 patients). Each patient in the exercise group underwent an individualized program of muscular-strength and aerobic training under the guidance of a physical therapist, whereas control patients received no formal exercise training. Cardiopulmonary stress testing was performed at base line (within one month after heart transplantation) and six months later. RESULTS As compared with the control group, the exercise group had significantly greater increases in peak oxygen consumption (mean increase, 4.4 ml per kilogram of body weight per minute [49 percent] vs. 1.9 ml per kilogram per minute [18 percent]; P=0.01) and workload (mean increase, 35 W [59 percent] vs. 12 W [18 percent]; P=0.01) and a greater reduction in the ventilatory equivalent for carbon dioxide (mean decrease, 13 [20 percent] vs. 6 [11 percent]; P=0.02). The mean dose of prednisone, the number of patients taking antihypertensive medications, the average number of episodes of rejection and of infection during the study period, and weight gain did not differ significantly between the groups. CONCLUSIONS When initiated early after cardiac transplantation, exercise training increases the capacity for physical work.


American Journal of Cardiology | 1993

Impact of left ventricular cavity size on survival in advanced heart failure.

Thomas H. Lee; Michele A. Hamilton; Lynne Warner Stevenson; Jaime Moriguchi; Gregg C. Fqnarow; John S. Child; Hillel Laks; Julie A. Walden

To determine the prevalence and significance of abnormal thyroid hormone metabolism in congestive heart failure, free thyroxine (T4) index, free triiodothyronine (T3) index, reverse T3 and thyrotropin levels were obtained in 84 hospitalized patients with chronic advanced heart failure. Free T4 index was normal in all patients. Free T3 index was reduced or reverse T3 elevated, or both, leading to a low free T3 index/reverse T3 ratio in 49 (58%) of the 84 patients. A low free T3 index/reverse T3 ratio was associated with higher right atrial, pulmonary artery and pulmonary capillary wedge pressures and lower ejection fraction, cardiac index, serum sodium, albumin and total lymphocyte count. In multivariate analysis, the free T3 index/reverse T3 ratio was the only independent predictor of poor 6 week outcome (p less than 0.001); the actuarial 1 year survival rate was 100% for patients with a normal ratio and only 37% for those with a low ratio (p less than 0.0001). A low free T3 index/reverse T3 ratio is associated with poor ventricular function and nutritional status and is the strongest predictor yet identified for short-term outcome in patients with advanced heart failure.

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Dive into the Michele A. Hamilton's collaboration.

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J. Kobashigawa

Cedars-Sinai Medical Center

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J. Patel

Cedars-Sinai Medical Center

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Jaime Moriguchi

Cedars-Sinai Medical Center

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M. Kittleson

Cedars-Sinai Medical Center

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L. Czer

Cedars-Sinai Medical Center

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D.H. Chang

Cedars-Sinai Medical Center

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Hillel Laks

University of California

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