Esmolol versus diltiazem in the treatment of postoperative atrial fibrillation/atrial flutter after open heart surgery.

BACKGROUND: Supraventricular tachyarrhythmias are common after open heart surgery. Possible causative factors for these arrhythmias include operative trauma, atrial ischemia, electrolyte imbalances, pericardial irritation, and excess catecholamines. Two agents commonly used to control ventricular rate in atrial fibrillation or atrial flutter (AF/AFL) are beta-blockers and calcium channel blockers. METHODS AND RESULTS: This randomized study was designed to compare the safety and efficacy of intravenous diltiazem versus intravenous esmolol in patients with postoperative AF/AFL after coronary bypass surgery and/or valve replacement surgery. A comparative cost analysis was also performed. Thirty patients received either esmolol (n = 15) or diltiazem (n = 15) for AF/AFL. During the first 6 hours of treatment, 66.6% of esmolol-treated patients converted to sinus rhythm compared with 13.3% of the diltiazem-treated patients (P <.05). At 24 hours, 66.6% of the diltiazem group converted to SR compared with 80% of the esmolol group (not significant). Drug-induced side effects, time to rate control (<90 beats/min), number of patients requiring cardioversion, and length of hospitalization were similar for the two groups. The drug cost/successfully treated patient for esmolol versus diltiazem was $254 versus $437 at 6 hours and $529 versus $262 at 24 hours. CONCLUSIONS: Although this is a small study, it suggests that esmolol is more effective in converting patients to normal sinus rhythm than diltiazem during the initial dosing period. No differences in conversion rates were observed between the two groups after 24 hours. Additional studies are needed to confirm whether esmolol is the initial drug of choice in patients with postoperative AF/AFL after coronary bypass surgery.

A population-based treat-to-target pharmacoeconomic analysis of HMG-CoA reductase inhibitors in hypercholesterolemia.

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors have become the drugs of choice for the treatment of patients with hypercholesterolemia. However, one of the major concerns with these drugs is cost. In an attempt to develop a cost-effective treatment strategy for patients referred to our lipid clinic, we conducted a meta-analysis to estimate the lipid-lowering efficacy of the various HMG-CoA reductase inhibitors alone or in combination with niacin or cholestyramine. Based on cholesterol-lowering efficacy estimates derived from a literature-based meta-analysis, we performed a population-based treat-to-target analysis. Fifty-six trials with 101 monotherapy cohorts and 20 trials with 31 combination-therapy cohorts (573 patients) were included in the meta-analysis. Based on reduction in low-density lipoprotein cholesterol (LDL-C), the most effective monotherapy was atorvastatin and the least effective monotherapy was fluvastatin. Combination therapy was more effective in reducing LDL-C than monotherapy with the respective HMG-CoA reductase inhibitor. However, on the basis of dollars spent per percentage of LDL-C reduction, combination therapy was frequently less cost-effective than monotherapy. In addition, combination therapy was associated with a higher rate of noncompliance and a greater risk of drug-drug interactions. As a result, we based our treat-to-target analysis on the use of monotherapy as first-line treatment, with combination therapy reserved for patients failing to achieve the target LDL-C levels of the US National Cholesterol Education Program Adult Treatment Panel II (NCEP ATP-II) with monotherapy. In the population-based treat-to-target analysis, atorvastatin was the most cost-effective drug for high-risk patients (those with coronary heart disease [CHD]), whereas fluvastatin was the most cost-effective agent for low-risk patients (<2 risk factors for CHD) and moderate-risk patients (> or =2 risk factors for CHD). If 1 drug is chosen to treat all patients (i.e., in cases of formulary restriction), atorvastatin would be the most cost-effective agent. In adapting the findings on cholesterol-lowering efficacy from this analysis to our lipid clinic, we concluded that the most cost-effective treatment approach is to individualize the selection of an HMG-CoA reductase inhibitor based on both coronary risk and the LDL-C reduction required to achieve NCEP ATP-II goals. Based on our results, 2 agents--atorvastatin and fluvastatin--should be available on the formulary.

Cost-minimization analysis of intravenous adenosine and dipyridamole in thallous chloride TI 201 SPECT myocardial perfusion imaging.

OBJECTIVE: To conduct a cost-minimization analysis of intravenous adenosine and intravenous dipyridamole in thallous chloride TI 201 single-photon emission computed tomography (SPECT) myocardial perfusion imaging. DESIGN: A retrospective, open-label, cost-minimization analysis. SETTING: University hospital, outpatient nuclear medicine department. PATIENTS: Eighty-three patients undergoing dipyridamole TI 201 SPECT and 166 patients undergoing adenosine TI 201 SPECT. MAIN OUTCOME MEASURES: A cost-minimization analysis was conducted using a direct cost accounting approach estimating institutional costs. For the purpose of this study, sensitivity and specificity between adenosine SPECT and dipyridamole SPECT were assumed to be identical. Key costs evaluated included acquisition, administration, monitoring, treatment of adverse effects, follow-up care, and repeat tests. RESULTS: Adenosine increased heart rate and lowered blood pressure to a significantly greater extent than dipyridamole. The frequency of adverse reactions was not significantly different (p = 0.103) between adenosine (1.64 +/- 1.32 per patient) and dipyridamole (1.36 +/- 1.23 per patient). The frequency of prolonged and late-onset adverse effects was significantly greater for dipyridamole than for adenosine (p < 0.001). The frequency of adverse events requiring medical intervention was statistically greater for dipyridamole (24%) compared with adenosine (5%) (p < 0.00001). Total cost was significantly less for adenosine ($378.50 +/- $128.20 per patient) compared with dipyridamole ($485.60 +/- $230.40). Although adenosine had a significantly greater acquisition cost than dipyridamole (p < 0.0001), administration, monitoring, and adverse reaction costs were significantly less for adenosine than for dipyridamole. CONCLUSIONS: The cost of using dipyridamole is significantly greater than the cost of using adenosine despite adenosine's high acquisition cost. Adenosine is less expensive to use because of lower administration costs, monitoring costs, and adverse effect costs. Adenosine should be the agent of choice for pharmacologic vasodilation in the setting of myocardial perfusion imaging.

Outcomes and costs of positron emission tomography: comparison of intravenous adenosine and intravenous dipyridamole.

The objective of this study was to compare the cost of intravenous adenosine and intravenous dipyridamole in positron emission tomography (PET) in patients with coronary artery disease. A retrospective, open-label, case-control, cost-effectiveness analysis was performed in the out-patient nuclear medicine department of a university hospital. Thirty-six patients underwent dipyridamole PET, and 72 matched patients underwent adenosine PET. A cost-effectiveness analysis was conducted using a direct cost accounting approach to estimate institutional costs. Key costs evaluated included acquisition cost, administration cost, monitoring cost, cost of management of side effects, and cost of follow-up care. The total cost of adenosine PET and dipyridamole PET was divided by their respective predictive accuracies to provide a total cost adjusted for efficacy. Adenosine increased heart rate and lowered systolic blood pressure to a significantly greater extent than dipyridamole. The number of patients experiencing adverse drug reactions was significantly greater for adenosine (82%) than for dipyridamole (67%), but the frequency of prolonged (> 5 minutes) and late-onset side effects was significantly greater for dipyridamole than for adenosine. The frequency of side effects requiring medical intervention was also significantly greater for dipyridamole (53%) than for adenosine (6%). Although adenosine had a significantly greater acquisition cost than dipyridamole, costs of monitoring, management of side effects, and follow-up care were significantly less for adenosine than for dipyridamole. As a result, the total cost of using dipyridamole is significantly greater ($928.00 per patient) than the total cost of using adenosine ($672.00 per patient). Based on these results, adenosine may be the drug of choice for pharmacologic vasodilation for PET.

Cost-minimization analysis of initial antihypertensive therapy in patients with mild-to-moderate essential diastolic hypertension.

In addition to efficacy and safety, the cost of therapy has become an increasingly important factor to consider when selecting drugs to treat patients with mild-to-moderate hypertension. However, acquisition prices alone do not determine the total cost of therapy. To better assess total costs, we conducted a systematic, retrospective, cost-minimization analysis of drugs used to treat 673 patients with newly diagnosed, mild-to-moderate (> 95 to < 110 mmHg) diastolic hypertension between the years 1985 and 1992. Patients included in the study had started antihypertensive monotherapy, and a minimum of one dose titration was required before adding another antihypertensive agent to the regimen. A patient had to have a diastolic blood pressure of < or = 90 mmHg while undergoing therapy to be included in the analysis. Drug classes included diuretics, beta-adrenergic blockers, centrally acting alpha 2-agonists, alpha 1-adrenergic blockers, calcium channel blockers, and angiotensin-converting enzyme (ACE) inhibitors. Costs, adjusted to 1992 price levels, were analyzed for 32 individual agents for each of the following five cost variables: initial drug acquisition, supplemental drug acquisition, laboratory monitoring, clinic visits, and treatment of side effects. Mean total costs per patient for all five variables by drug class were $895 for beta-blockers, $1043 for diuretics, $1165 for centrally acting alpha 2-agonists, $1243 for ACE inhibitors, $1288 for alpha 1-blockers, and $1425 for calcium channel blockers. However, costs within each class varied considerably. Acquisition cost was often a poor predictor of the total cost of treatment. Therefore, acquisition cost must be considered in conjunction with a number of outcome variables to assess the true cost of antihypertensive therapy.

Efficacy and safety of early versus late initiation of warfarin during heparin therapy in acute thromboembolism.

There is no universally accepted approach to the initiation of systemic anticoagulant therapy. In an open, randomized study, two anticoagulant regimens that differed only in the timing of warfarin therapy after the start of heparin were compared. We randomized 119 patients with acute thromboembolic events to receive warfarin either within 48 hours of the start of heparin (early group, n = 63) or 96 hours or later after the start of heparin (late group, n = 56). Heparin was given as a 5000 IU bolus as a constant infusion titrated to maintain the activated partial thromboplastin time at 1.5 to 2 times control values. Warfarin was started at 10 mg daily for 3 days and the dose was titrated to maintain the prothrombin time at 1.2 to 1.5 times control values. There were no significant differences between the early and late warfarin groups with regard to age, sex, indication for anticoagulation, heparin dose, mean activated partial thromboplastin time during heparin, warfarin dose at discharge, length of warfarin therapy before discharge, bleeding, recurrent thromboembolic events, or mortality rates. Time to the start of warfarin after heparin was 31 hours and 108 hours in the early and late groups, respectively. Length of hospitalization, hospital costs, and the incidence of heparin-induced infusion phlebitis and thrombocytopenia were significantly less in the early group compared with the late group. Early initiation of warfarin after heparin is safer, less expensive, and as effective as the late initiation of warfarin.