Cost-effectiveness of the implantable cardioverter-defibrillator: Effect of improved battery life and comparison with amiodarone therapy

AbstractThe implantable cardioverter-defibrillator (ICD) greatly reduces the incidence of sudden cardiac death among patients with recurrent sustained ventricular tachycardia and fibrillation who do not respond to conventional antiarrhythmic therapy. A cost-effectiveness analysis was performed, comparing the ICD, amiodarone and conventional agents. Actual variable costs of hospitalization and follow-up care were used for 21 ICD- and 43 amiodarone-treated patients. Life expectancy and total variable costs were predicted with use of a Markov decision analytic model. Clinical event rates and probabilities were based on published reports or expert opinion.Life expectancy with an ICD (6.1 years) was 50% greater than that associated with treatment with amiodarone (3.9 years) and 2.5 times that associated with conventional treatment (2.5 years). Assuming replacement every 24 months, ICD lifetime treatment costs (in 1989 dollars) for a 55-year old patient are expected to be $89,600 compared with$24,800 for amiodarone and $16,100 for conventional therapy, yielding a marginal cost/effectiveness ratio for ICD versus amiodarone therapy of$29,200/year of life saved, which is comparable to that of other accepted medical treatments. If technologic improvements extend average battery life to 36 months, the marginal cost/effectiveness ratio would be $21,880/ year of life saved, and at 96 months it would be$13,800/year of life saved. Patient age at implantation did not significantly affect these results.If quality of life on amiodarone therapy is 30% lower than that with the ICD, the marginal cost/effectiveness ratio decreases by 35%. If the quality of life for patients receiving drugs is 40% lower than that of patients treated with an ICD, use of the defibrillator becomes the dominant strategy

Hospital Mortality in Women and Men With Acute Cardiac Ischemia: A Prospective Multicenter Study

AbstractObjectives. This study sought to determine gender differences in hospital mortality in patients with acute cardiac ischemia.Background. It is unclear why women experience higher mortality from acute myocardial infarction (AMI) than men and whether this applies to all patients with acute ischemia.Methods. We analyzed data from a prospective multicenter study involving patients presenting to the emergency department (ED) with symptoms suggestive of acute ischemia.Results. Of 10,783 patients, 5,221 (48.4%) were women. Mean age was 60.5 years for women and 56.9 for men (p < 0.001). Women had more hypertension (54.6% vs. 45.9%, p < 0.001) and diabetes (23.3% vs. 17.0%, p < 0.001) than men but fewer previous AMIs (21.1% vs. 28.9%, p < 0.001). Acute ischemia was confirmed in 1,090 women (20.8%) and 1,451 men (26.1%, p < 0.001), including AMI in 322 women (6.2%) and 572 men (10.3%, p < 0.001). Women with an AMI were in a higher Killip class than men: class I in 60.3% versus 72.2%, class II in 19.3% versus 16%, class III in 15.5% versus 8.7% and class IV in 5% versus 3.1%, respectively (p = 0.001). There was no significant difference in mortality from acute ischemia between genders (4.0% vs. 3.5%, p = 0.6), but there was a trend for higher AMI mortality in women (10.3% vs. 7.4%, p = 0.1). After controlling for age, diabetes, heart failure and presenting blood pressure, gender did not predict mortality from acute ischemia (odds ratio 0.9, 95% confidence interval 0.5 to 1.4, p = 0.5).Conclusions. Among patients presenting to the ED with acute cardiac ischemia, gender does not appear to be an independent predictor of hospital mortality. The trend for higher mortality in women from AMI can be explained by their older age, greater frequency of diabetes and higher Killip class on presentation.(J Am Coll Cardiol 1997;29:1490–6

Presentations of Acute Myocardial Infarction in Men and Women

OBJECTIVE: To assess the influence of gender on the likelihood of acute myocardial infarction (AMI) among emergency department (ED) patients with symptoms suggestive of acute cardiac ischemia, and to determine whether any specific presenting signs or symptoms are associated more strongly with AMI in women than in men. DESIGN: Analysis of cohort data from a prospective clinical trial. SETTING: Emergency departments of 10 hospitals of varying sizes and types in the United States. PATIENTS: Patients 30 years of age or older (n = 10,525) who presented to the ED with chest pain or other symptoms suggestive of acute cardiac ischemia. MEASUREMENTS AND MAIN RESULTS: The prevalence of AMI was determined for men and women, and a multivariable logistic regression model predicting AMI was developed to adjust for patients’ demographic and clinical characteristics. AMI was almost twice as common in men as in women (10% vs 6%). Controlling for demographics, presenting signs and symptoms, electrocardiogram features, and hospital, male gender was a significant predictor of AMI (odds ratio [OR] 1.7; 95% confidence interval [CI] 1.4 , 2.0). The gender effect was eliminated, however, among patients with ST-segment elevations on electrocardiogram (OR 1.1; 95% CI 0.7, 1.7) and among patients with signs of congestive heart failure (CHF) (OR 1.1; 95% CI 0.8, 1.5). Signs of CHF were associated with AMI among women (OR 1.9; 95% CI 1.4, 2.6) but not men (OR 1.0; 95% CI 0.8, 1.3). Among patients who presented to EDs with chest pain or other symptoms suggestive of acute cardiac ischemia, AMI was more likely in men than in women. Among women with ST-segment elevation or signs of CHF, however, AMI likelihood was similar to that in men with these characteristics

A predictive model to identify patients with suspected acute coronary syndromes at high risk of cardiac arrest or in-hospital mortality: An IMMEDIATE Trial sub-study

Background: The IMMEDIATE Trial of emergency medical service use of intravenous glucose–insulin–potassium (GIK) very early in acute coronary syndromes (ACS) showed benefit for the composite outcome of cardiac arrest or in-hospital mortality. Objectives: This analysis of IMMEDIATE Trial data sought to develop a predictive model to help clinicians identify patients at highest risk for this outcome and most likely to benefit from GIK. Methods: Multivariable logistic regression was used to develop a predictive model for the composite endpoint cardiac arrest or in-hospital mortality using the 460 participants in the placebo arm of the IMMEDIATE Trial. Results: The final model had four variables: advanced age, low systolic blood pressure, ST elevation in the presenting electrocardiogram, and duration of time since ischemic symptom onset. Predictive performance was good, with a C statistic of 0.75, as was its calibration. Stratifying patients into three risk categories based on the model's predictions, there was an absolute risk reduction of 8.6% with GIK in the high-risk tertile, corresponding to 12 patients needed to treat to prevent one bad outcome. The corresponding values for the low-risk tertile were 0.8% and 125, respectively. Conclusions: The multivariable predictive model developed identified patients with very early ACS at high risk of cardiac arrest or death. Using this model could assist treating those with greatest potential benefit from GIK

In-hospital measurement of left ventricular ejection fraction and one-year outcomes in acute coronary syndromes: results from the IMMEDIATE Trial

Background: In patients with acute coronary syndrome (ACS), reduced left ventricular ejection fraction (LVEF) is a known marker for increased mortality. However, the relationship between LVEF measured during index ACS hospitalization and mortality and heart failure (HF) within 1 year are less well-defined. Methods: We performed a retrospective analysis of 445 participants in the IMMEDIATE Trial who had LVEF measured by left ventriculography or echocardiogram during hospitalization. Results: Adjusting for age and coronary artery disease (CAD) history, lower LVEF was significantly associated with 1-year mortality or hospitalization for HF. For every 5 % LVEF reduction, the hazard ratio [HR] was 1.26 (95 % CI 1.15, 1.38, P 40 (HR 3.59; 95 % CI 2.05, 6.27, P < 0.001). The HRs for the association of LVEF with the study outcomes were similar whether measured by left ventriculography or by echocardiography, (respectively, HR 1.32; 95 % CI 1.15, 1.51 and 1.21; 95 % CI 1.106, 1.35, interaction P = 0.32) and whether done within 24 h or not within 24 h (respectively, HR 1.28; 95 % CI 1.10, 1.50 and 1.23; 95 % CI 1.10, 1.38, interaction P = 0.67). Conclusions: Among patients with ACS, lower in-hospital LVEF is associated with increased 1-year mortality or hospitalization for HF, regardless of the method or timing of the LVEF assessment. This has prognostic implications for clinical practice and suggests the possibility of using various methods of LVEF determination in clinical research

A predictive model to identify patients with suspected acute coronary syndromes at high risk of cardiac arrest or in-hospital mortality: An IMMEDIATE Trial sub-study

The IMMEDIATE Trial of emergency medical service use of intravenous glucose–insulin–potassium (GIK) very early in acute coronary syndromes (ACS) showed benefit for the composite outcome of cardiac arrest or in-hospital mortality. This analysis of IMMEDIATE Trial data sought to develop a predictive model to help clinicians identify patients at highest risk for this outcome and most likely to benefit from GIK. Multivariable logistic regression was used to develop a predictive model for the composite endpoint cardiac arrest or in-hospital mortality using the 460 participants in the placebo arm of the IMMEDIATE Trial. The final model had four variables: advanced age, low systolic blood pressure, ST elevation in the presenting electrocardiogram, and duration of time since ischemic symptom onset. Predictive performance was good, with a C statistic of 0.75, as was its calibration. Stratifying patients into three risk categories based on the models predictions, there was an absolute risk reduction of 8.6% with GIK in the high-risk tertile, corresponding to 12 patients needed to treat to prevent one bad outcome. The corresponding values for the low-risk tertile were 0.8% and 125, respectively. The multivariable predictive model developed identified patients with very early ACS at high risk of cardiac arrest or death. Using this model could assist treating those with greatest potential benefit from GIK