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Dive into the research topics where Christopher M. O'Connor is active.

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Featured researches published by Christopher M. O'Connor.


Circulation | 2003

Clopidogrel for Coronary Stenting Response Variability, Drug Resistance, and the Effect of Pretreatment Platelet Reactivity

Paul A. Gurbel; Kevin P. Bliden; Bonnie L. Hiatt; Christopher M. O'Connor

Background Clopidogrel is administered to prevent stent thrombosis; however, the uniformity of platelet inhibition after treatment and the influence of pretreatment reactivity on drug response have not been described. Methods and Results Platelet aggregation (5 and 20 μmol/L ADP), the activation of glycoprotein IIb/IIIa (PAC‐1 antibody), and the expression of P‐selectin were measured in patients undergoing elective coronary stenting (n=96) at baseline and at 2 hours, 24 hours, 5 days, and 30 days after stenting. All patients received aspirin (325 mg). Clopidogrel (300 mg) was administered in the catheterization laboratory and followed by 75 mg daily. There was marked interindividual variability in drug response as measured by all markers that showed a normal distribution. Resistance, defined as baseline aggregation (%) minus posttreatment aggregation (%) ≤10% by 5 μmol/L ADP, was present in 31% and 15% of patients at 5 and 30 days, respectively. Patients with the highest pretreatment platelet reactivity remained the most reactive at 24 hours after treatment (P<0.0001). Conclusions Interindividual variability in the platelet inhibitory response from clopidogrel occurs in patients undergoing elective coronary stenting. Patients with high pretreatment reactivity are least protected. Alternative pharmacological strategies and the association of adverse ischemic events should be investigated in these patients. (Circulation. 2003; 107:2908‐2913.)


JAMA | 2009

Efficacy and Safety of Exercise Training in Patients With Chronic Heart Failure: HF-ACTION Randomized Controlled Trial

Christopher M. O'Connor; David J. Whellan; Kerry L. Lee; Steven J. Keteyian; Lawton S. Cooper; Stephen J. Ellis; Eric S. Leifer; William E. Kraus; Dalane W. Kitzman; James A. Blumenthal; David S. Rendall; Nancy Houston Miller; Jerome L. Fleg; Kevin A. Schulman; Robert S. McKelvie; Faiez Zannad; Ileana L. Piña

CONTEXT Guidelines recommend that exercise training be considered for medically stable outpatients with heart failure. Previous studies have not had adequate statistical power to measure the effects of exercise training on clinical outcomes. OBJECTIVE To test the efficacy and safety of exercise training among patients with heart failure. DESIGN, SETTING, AND PATIENTS Multicenter, randomized controlled trial of 2331 medically stable outpatients with heart failure and reduced ejection fraction. Participants in Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) were randomized from April 2003 through February 2007 at 82 centers within the United States, Canada, and France; median follow-up was 30 months. INTERVENTIONS Usual care plus aerobic exercise training, consisting of 36 supervised sessions followed by home-based training, or usual care alone. MAIN OUTCOME MEASURES Composite primary end point of all-cause mortality or hospitalization and prespecified secondary end points of all-cause mortality, cardiovascular mortality or cardiovascular hospitalization, and cardiovascular mortality or heart failure hospitalization. RESULTS The median age was 59 years, 28% were women, and 37% had New York Heart Association class III or IV symptoms. Heart failure etiology was ischemic in 51%, and median left ventricular ejection fraction was 25%. Exercise adherence decreased from a median of 95 minutes per week during months 4 through 6 of follow-up to 74 minutes per week during months 10 through 12. A total of 759 patients (65%) in the exercise training group died or were hospitalized compared with 796 patients (68%) in the usual care group (hazard ratio [HR], 0.93 [95% confidence interval {CI}, 0.84-1.02]; P = .13). There were nonsignificant reductions in the exercise training group for mortality (189 patients [16%] in the exercise training group vs 198 patients [17%] in the usual care group; HR, 0.96 [95% CI, 0.79-1.17]; P = .70), cardiovascular mortality or cardiovascular hospitalization (632 [55%] in the exercise training group vs 677 [58%] in the usual care group; HR, 0.92 [95% CI, 0.83-1.03]; P = .14), and cardiovascular mortality or heart failure hospitalization (344 [30%] in the exercise training group vs 393 [34%] in the usual care group; HR, 0.87 [95% CI, 0.75-1.00]; P = .06). In prespecified supplementary analyses adjusting for highly prognostic baseline characteristics, the HRs were 0.89 (95% CI, 0.81-0.99; P = .03) for all-cause mortality or hospitalization, 0.91 (95% CI, 0.82-1.01; P = .09) for cardiovascular mortality or cardiovascular hospitalization, and 0.85 (95% CI, 0.74-0.99; P = .03) for cardiovascular mortality or heart failure hospitalization. Other adverse events were similar between the groups. CONCLUSIONS In the protocol-specified primary analysis, exercise training resulted in nonsignificant reductions in the primary end point of all-cause mortality or hospitalization and in key secondary clinical end points. After adjustment for highly prognostic predictors of the primary end point, exercise training was associated with modest significant reductions for both all-cause mortality or hospitalization and cardiovascular mortality or heart failure hospitalization. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00047437.


The New England Journal of Medicine | 1996

Effect of Amlodipine on Morbidity and Mortality in Severe Chronic Heart Failure

Milton Packer; Christopher M. O'Connor; Jalal K. Ghali; Milton L. Pressler; Peter E. Carson; Robert N. Belkin; Alan B. Miller; Gerald W. Neuberg; David J. Frid; John H. Wertheimer; Anne B. Cropp; David L. DeMets

BACKGROUND Previous studies have shown that calcium-channel blockers increase morbidity and mortality in patients with chronic heart failure. We studied the effect of a new calcium-channel blocker, amlodipine, in patients with severe chronic heart failure. METHODS We randomly assigned 1153 patients with severe chronic heart failure and ejection fractions of less than 30 percent to double-blind treatment with either placebo (582 patients) or amlodipine (571 patients) for 6 to 33 months, while their usual therapy was continued. The randomization was stratified on the basis of whether patients had ischemic or nonischemic causes of heart failure. The primary end point of the study was death from any cause and hospitalization for major cardiovascular events. RESULTS Primary end points were reached in 42 percent of the placebo group and 39 percent of the amlodipine group, representing a 9 percent reduction in the combined risk of fatal and nonfatal events with amlodipine (95 percent confidence interval, 24 percent reduction to 10 percent increase; P=0.31). A total of 38 percent of the patients in the placebo group died, as compared with 33 percent of those in the amlodipine group, representing a 16 percent reduction in the risk of death with amlodipine (95 percent confidence interval, 31 percent reduction to 2 percent increase; P=0.07). Among patients with ischemic heart disease, there was no difference between the amlodipine and placebo groups in the occurrence of either end point. In contrast, among patients with nonischemic cardiomyopathy, amlodipine reduced the combined risk of fatal and nonfatal events by 31 percent (P=0.04) and decreased the risk of death by 46 percent (P<0.001). CONCLUSIONS Amlodipine did not increase cardiovascular morbidity or mortality in patients with severe heart failure. The possibility that amlodipine prolongs survival in patients with nonischemic dilated cardiomyopathy requires further study.


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.


The New England Journal of Medicine | 2011

Effect of Nesiritide in Patients with Acute Decompensated Heart Failure

Christopher M. O'Connor; Randall C. Starling; Adrian F. Hernandez; Paul W. Armstrong; Kenneth Dickstein; Vic Hasselblad; Gretchen Heizer; Michel Komajda; B. Massie; John J.V. McMurray; Markku S. Nieminen; Craig J. Reist; Jean-Lucien Rouleau; Karl Swedberg; Kirkwood F. Adams; Stefan D. Anker; Dan Atar; Alexander Battler; R. Botero; N. R. Bohidar; Javed Butler; Nadine Clausell; Ramón Corbalán; Maria Rosa Costanzo; Ulf Dahlström; L. I. Deckelbaum; R. Diaz; Mark E. Dunlap; Justin A. Ezekowitz; D. Feldman

BACKGROUND Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality associated with this agent. METHODS We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days. RESULTS Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P=0.03) and 24 hours (68.2% vs. 66.1%, P=0.007), but the prespecified level for significance (P≤0.005 for both assessments or P≤0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference, -0.7 percentage points; 95% confidence interval [CI], -2.1 to 0.7; P=0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference, -0.4 percentage points; 95% CI, -1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P=0.11). CONCLUSIONS Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure. (Funded by Scios; ClinicalTrials.gov number, NCT00475852.).


Biological Psychiatry | 2005

Mood Disorders in the Medically Ill: Scientific Review and Recommendations

Dwight L. Evans; Dennis S. Charney; Lydia Lewis; Robert N. Golden; Jack M. Gorman; K. Ranga Rama Krishnan; Charles B. Nemeroff; J. Douglas Bremner; Robert M. Carney; James C. Coyne; Mahlon R. DeLong; Nancy Frasure-Smith; Alexander H. Glassman; Philip W. Gold; Igor Grant; Lisa P. Gwyther; Gail Ironson; Robert L. Johnson; Andres M. Kanner; Wayne Katon; Peter G. Kaufmann; Francis J. Keefe; Terence A. Ketter; Thomas Laughren; Jane Leserman; Constantine G. Lyketsos; William M. McDonald; Bruce S. McEwen; Andrew H. Miller; Christopher M. O'Connor

OBJECTIVE The purpose of this review is to assess the relationship between mood disorders and development, course, and associated morbidity and mortality of selected medical illnesses, review evidence for treatment, and determine needs in clinical practice and research. DATA SOURCES Data were culled from the 2002 Depression and Bipolar Support Alliance Conference proceedings and a literature review addressing prevalence, risk factors, diagnosis, and treatment. This review also considered the experience of primary and specialty care providers, policy analysts, and patient advocates. The review and recommendations reflect the expert opinion of the authors. STUDY SELECTION/DATA EXTRACTION Reviews of epidemiology and mechanistic studies were included, as were open-label and randomized, controlled trials on treatment of depression in patients with medical comorbidities. Data on study design, population, and results were extracted for review of evidence that includes tables of prevalence and pharmacological treatment. The effect of depression and bipolar disorder on selected medical comorbidities was assessed, and recommendations for practice, research, and policy were developed. CONCLUSIONS A growing body of evidence suggests that biological mechanisms underlie a bidirectional link between mood disorders and many medical illnesses. In addition, there is evidence to suggest that mood disorders affect the course of medical illnesses. Further prospective studies are warranted.


Circulation | 2007

Treatment of Hypertension in the Prevention and Management of Ischemic Heart Disease: A Scientific Statement From the American Heart Association Council for High Blood Pressure Research and the Councils on Clinical Cardiology and Epidemiology and Prevention

Clive Rosendorff; Henry R. Black; Christopher P. Cannon; Bernard J. Gersh; Joel M. Gore; Joseph L. Izzo; Norman M. Kaplan; Christopher M. O'Connor; Patrick T. O'Gara; Suzanne Oparil

Epidemiological studies have established a strong association between hypertension and coronary artery disease (CAD). Hypertension is a major independent risk factor for the development of CAD, stroke, and renal failure. The optimal choice of antihypertensive agents remains controversial, and there are only partial answers to important questions in the treatment of hypertension in the prevention and management of ischemic heart disease (IHD), such as: ● What are the appropriate systolic blood pressure (SBP) and diastolic blood pressure (DBP) targets in patients at high risk of developing CAD or in those with established CAD? ● Are the beneficial effects of treatment simply a function of blood pressure (BP) lowering, or do particular classes of drugs have uniquely protective actions in addition to lowering BP? ● Are there antihypertensive drugs that have shown particular efficacy in the primary and secondary prevention of IHD? ● Which antihypertensive drugs should be used in patients who have established CAD with stable or unstable angina pectoris, in those with non–ST-elevation myocardial infarction (NSTEMI), and in those with ST-elevation myocardial infarction (STEMI)?


Journal of the American College of Cardiology | 2007

Characteristics, Treatments, and Outcomes of Patients With Preserved Systolic Function Hospitalized for Heart Failure. A Report From the OPTIMIZE-HF Registry

Gregg C. Fonarow; Wendy Gattis Stough; William T. Abraham; Nancy M. Albert; Mihai Gheorghiade; Barry H. Greenberg; Christopher M. O'Connor; Jie Lena Sun; Clyde W. Yancy; James B. Young

OBJECTIVES We sought to evaluate the characteristics, treatments, and outcomes of patients with preserved and reduced systolic function heart failure (HF). BACKGROUND Heart failure with preserved systolic function (PSF) is common but not well understood. METHODS This analysis of the OPTIMIZE-HF (Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients With Heart Failure) registry compared 20,118 patients with left ventricular systolic dysfunction (LVSD) and 21,149 patients with PSF (left ventricular ejection fraction [EF] > or =40%). Sixty- to 90-day follow-up was obtained in a pre-specified 10% sample of patients. Analyses of patients with PSF defined as EF >50% were also performed for comparison. RESULTS Patients with PSF (EF > or =40%) were more likely to be older, female, and Caucasian and to have a nonischemic etiology. Although length of hospital stay was the same in both groups, risk of in-hospital mortality was lower in patients with PSF (EF > or =40%) (2.9% vs. 3.9%; p < 0.0001). During 60- to 90-day post-discharge follow-up, patients with PSF (EF > or =40%) had a similar mortality risk (9.5% vs. 9.8%; p = 0.459) and rehospitalization rates (29.2% vs. 29.9%; p = 0.591) compared with patients with LVSD. Findings were comparable with those with PSF defined as EF >50%. In a risk- and propensity-adjusted model, there were no significant relationships between discharge use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker or beta-blocker and 60- to 90-day mortality and rehospitalization rates in patients with PSF. CONCLUSIONS Data from the OPTIMIZE-HF registry reveal a high prevalence of HF with PSF, and these patients have a similar post-discharge mortality risk and equally high rates of rehospitalization as patients with HF and LVSD. Despite the burden to patients and health care systems, data are lacking on effective management strategies for patients with HF and PSF. (Organized Program To Initiate Lifesaving Treatment In Hospitalized Patients With Heart Failure [OPTIMIZE-HF]); http://www.clinicaltrials.gov/ct/show/NCT00344513?order=1; NCT00344513).


The New England Journal of Medicine | 2009

Coronary Bypass Surgery with or without Surgical Ventricular Reconstruction

Roger Jones; Eric J. Velazquez; Robert E. Michler; George Sopko; Jae K. Oh; Christopher M. O'Connor; James A. Hill; Lorenzo Menicanti; Zygmunt Sadowski; Patrice Desvigne-Nickens; Jean L. Rouleau; Kerry L. Lee

BACKGROUND Surgical ventricular reconstruction is a specific procedure designed to reduce left ventricular volume in patients with heart failure caused by coronary artery disease. We conducted a trial to address the question of whether surgical ventricular reconstruction added to coronary-artery bypass grafting (CABG) would decrease the rate of death or hospitalization for cardiac causes, as compared with CABG alone. METHODS Between September 2002 and January 2006, a total of 1000 patients with an ejection fraction of 35% or less, coronary artery disease that was amenable to CABG, and dominant anterior left ventricular dysfunction that was amenable to surgical ventricular reconstruction were randomly assigned to undergo either CABG alone (499 patients) or CABG with surgical ventricular reconstruction (501 patients). The primary outcome was a composite of death from any cause and hospitalization for cardiac causes. The median follow-up was 48 months. RESULTS Surgical ventricular reconstruction reduced the end-systolic volume index by 19%, as compared with a reduction of 6% with CABG alone. Cardiac symptoms and exercise tolerance improved from baseline to a similar degree in the two study groups. However, no significant difference was observed in the primary outcome, which occurred in 292 patients (59%) who were assigned to undergo CABG alone and in 289 patients (58%) who were assigned to undergo CABG with surgical ventricular reconstruction (hazard ratio for the combined approach, 0.99; 95% confidence interval, 0.84 to 1.17; P=0.90). CONCLUSIONS Adding surgical ventricular reconstruction to CABG reduced the left ventricular volume, as compared with CABG alone. However, this anatomical change was not associated with a greater improvement in symptoms or exercise tolerance or with a reduction in the rate of death or hospitalization for cardiac causes. (ClinicalTrials.gov number, NCT00023595.)


JAMA | 2009

Effects of exercise training on health status in patients with chronic heart failure: HF-ACTION randomized controlled trial.

Kathryn E. Flynn; Ileana L. Piña; David J. Whellan; Li Lin; James A. Blumenthal; Stephen J. Ellis; Lawrence J. Fine; Jonathan G. Howlett; Steven J. Keteyian; Dalane W. Kitzman; William E. Kraus; Nancy Houston Miller; Kevin A. Schulman; John A. Spertus; Christopher M. O'Connor; Kevin P. Weinfurt

CONTEXT Findings from previous studies of the effects of exercise training on patient-reported health status have been inconsistent. OBJECTIVE To test the effects of exercise training on health status among patients with heart failure. DESIGN, SETTING, AND PATIENTS Multicenter, randomized controlled trial among 2331 medically stable outpatients with heart failure with left ventricular ejection fraction of 35% or less. Patients were randomized from April 2003 through February 2007. INTERVENTIONS Usual care plus aerobic exercise training (n = 1172), consisting of 36 supervised sessions followed by home-based training, vs usual care alone (n = 1159). Randomization was stratified by heart failure etiology, which was a covariate in all models. MAIN OUTCOME MEASURES Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scale and key subscales at baseline, every 3 months for 12 months, and annually thereafter for up to 4 years. The KCCQ is scored from 0 to 100 with higher scores corresponding to better health status. Treatment group effects were estimated using linear mixed models according to the intention-to-treat principle. RESULTS Median follow-up was 2.5 years. At 3 months, usual care plus exercise training led to greater improvement in the KCCQ overall summary score (mean, 5.21; 95% confidence interval, 4.42 to 6.00) compared with usual care alone (3.28; 95% confidence interval, 2.48 to 4.09). The additional 1.93-point increase (95% confidence interval, 0.84 to 3.01) in the exercise training group was statistically significant (P < .001). After 3 months, there were no further significant changes in KCCQ score for either group (P = .85 for the difference between slopes), resulting in a sustained, greater improvement overall for the exercise group (P < .001). Results were similar on the KCCQ subscales, and no subgroup interactions were detected. CONCLUSIONS Exercise training conferred modest but statistically significant improvements in self-reported health status compared with usual care without training. Improvements occurred early and persisted over time. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00047437.

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David J. Whellan

Thomas Jefferson University

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Ileana L. Piña

Albert Einstein College of Medicine

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