Steal-prone coronary circulation in chronically instrumented dogs: isoflurane versus adenosine

The influence of isoflurane and adenosine on left ventricular myocardial blood flow was investigated in dogs chronically instrumented for measurement of systemic and coronary hemodynamics, regional myocardial contractile function (with ultrasonic sonomicrometers), and myocardial perfusion (by the radioactive microsphere method). An Ameroid constrictor was implanted on the left circumflex coronary artery to produce a progressive stenosis that gradually reduced vascular reserve of the distal perfusion territory. The depletion of reserve was evaluated by daily monitoring of the hyperemic response to adenosine. A stenosis of moderate severity was considered present when left circumflex reserve was attenuated by approximately 60-70%. During left circumflex stenosis development, the left anterior descending coronary artery was totally occluded for 2 min each hour eight times daily with a hydraulic occluder to stimulate coronary collateral development over a period of 9-13 days. Contractile dysfunction during and flow debt repayment after each brief occlusion were used to monitor coronary collateral development. After stenosis and collateral development had occurred, the left anterior descending coronary artery was permanently occluded to simulate a condition of multivessel coronary artery disease with enhanced collateral development. In separate groups of experiments, hemodynamics and myocardial perfusion were measured before and after administration of adenosine (0.54 and 1.08 mg/min) or isoflurane (1.1 and 1.9%, end-tidal) and in the presence of either agent during adjustment of diastolic aortic pressure and heart rate to control levels. Total left anterior descending coronary artery occlusion in the presence of a moderate left circumflex stenosis produced an increase in mean arterial and left ventricular end diastolic pressures. Isoflurane decreased arterial pressure, left ventricular systolic pressure, and positive rate of increase of left ventricular pressure (dP/dt50) without altering heart rate. Administration of the high concentration of isoflurane reduced blood flow in normal areas and in regions distal to the partial (from 1.05 +/- 0.10 to 0.76 +/- 0.11 ml.min-1.g-1) or total coronary occlusion (from 0.64 +/- 0.10 to 0.41 +/- 0.11 ml.min-1.g-1). However, when arterial pressure and heart rate were restored to levels present in the conscious state, perfusion in all zones was maintained at control levels (1.06 +/- 0.11 for the stenotic and 0.69 +/- 0.12 ml.min-1.g-1 for the occluded region). Ratios of transmural blood flow between occluded and normal or occluded and stenotic zones were not different from the conscious state during a constant aortic pressure and heart rate.(ABSTRACT TRUNCATED AT 400 WORDS)     

DA8 Evaluating Health Outcomes and Pharmacoeconomic Literature

In 1997, the United States Pharmacopeia (USP) established an Ad Hoc Outcomes/Cost Effectiveness Advisory Panel to consider the development of specifications for compiling, indexing, and evaluating outcomes research/cost-effectiveness literature on a disease-specific basis. Such a resource could be used to support pharmaceutical therapy choice decision making by a variety of potential users. The USP had developed a protype health outcomes and pharmacoeconomic annotated registry of the literature on the disease state, congestive heart failure. Other organizations have established and are marketing pharmacoeconomic and health outcome literature registries, with two examples being the HEED database (OHE-IFPMA Database Ltd.) and the University of York NHS Centre for Reviews and Dissemination (DARE).
OBJECTIVE: To share experiences and to identify the needs of decision makers for outcome/pharmacoeconomic information and to discuss whether they are being met by currently available literature sources. Decision makers include health care practitioners, managed care organizations, third party payers, industry and governments.
WORKSHOP FORMAT: The USP congestive heart failure protype literature registry will be described and compared to currently available pharmacoeconomic/outcome databases. Participants will share their assessment of the currently available abstracting service/databases and determine if there is a role for further developments.
DESIRED OUTCOME: To determine if there is a need for a collaborative approach among interested parties to make relevant health outcome/pharmacoeconomic information more accessible to the drug therapy decision makers in a format that is "user friendly."     

CVA3 Adherence to Hypertension Therapy: The Effect of Initial Drug Choice

Health-care case management places pressure on decision makers to adopt treatment strategies that promote economic efficiency and hence profitability. Traditional costeffectiveness analysis (CEA), where the objective is to calculate cost-effectiveness ratios, can better inform decision making in markets where prices and efficacy vary widely. However, the threshold at which a given therapy becomes economically efficient relative to competing therapies is not evident from cost-effictiveness ratios alone.
OBJECTIVE: To illustrate the use of spatial techniques for identifying efficient treatment options, using statin therapy in secondary prevention of coronary heart disease (CHD) as a case study.
METHODS: We used a Markov model of CHD epidemiology and treatment to estimate cost-effectivness of 13 statin regimens versus no therapy in secondary prevention of CHD. Comparative efficacy was assessed using data from a recent trial (CURVES) that included these regimens. Patients were assumed to have a history of CHD with risk factors similar to those observed in the trial. CHD event risk was estimated using new subsequent-event risk equations from the Framingham Heart Study. Effectiveness was measured alternatively as gain in life expectancy and CHD events averted.
RESULTS: At usual starting doses, atorvastatin therapy provided the largest life expectancy gain and CHD event avoidance at the lowest cost per life-year gained ($12,900 and $23,400 for men and women, respectively), followed by simvastatin ($17,700 and $31,700), lovastatin ($18,800 and $33,700), pravastatin ($22,600 and $40,200), and fluvastatin ($23,800 and $42,000). Any desired level of effectiveness can be obtained at lowest cost with atorvastatin.
CONCLUSION: Economic efficiency is enhanced when atorvastatin is used to treat some or all patients requiring statin therapy in secondary prevention of CHD.     

Mesoatrial shunts for Budd-Chiari syndrome and inferior vena cava thrombosis: angiographic and hemodynamic evaluations

When inferior vena caval obstruction complicates the Budd-Chiari syndrome, conventional portosystemic shunts are not possible. The mesoatrial shunt has been devised to enable portal and sinusoidal decompression in these patients. Findings in 12 patients with Budd-Chiari syndrome and inferior vena caval obstruction in whom a mesoatrial shunt was performed are reported. Preoperative inferior vena cavography with pressure measurements is essential to determine the appropriate shunt procedure. Postoperatively, shunt patency is assessed with superior mesenteric arterial portography. Where possible, transvenous catheterization of the shunt is performed to confirm patency and assess hemodynamic function.     

Return to work of breast cancer survivors: a systematic review of intervention studies

Background  

Breast cancer management has improved dramatically in the past three decades and as a result, a population of working age women is breast cancer survivor. Interventions for breast cancer survivors have shown improvements in quality of life and in physical and psychological states. In contrast, efforts aimed at stimulating re-employment and return-to-work interventions for breast cancer survivors have not kept pace. The objective of this review was to study the effects and characteristics of intervention studies on breast cancer survivors in which the outcome was return to work.