Technology assessment in health care--decision makers and health care providers: what they need to know

The assessment of a new technology requires decision makers to gather information in many different fields. The questions addressed are technical, medical, ethical, legal and economic in nature. Learning from the experience of our own country and of others, we present here the sum of the information we deem necessary to decide on whether to adopt a new technology or not, and which strategy to choose for its implementation.

[Diagnostic, prognostic and therapeutic value of Doppler echocardiography in pulmonary embolism. Apropos of 41 cases]

In 41 patients with acute or recent pulmonary embolus (PE), a prospective study was conducted with cardiac Doppler sonography (CDS). The test is performed first in all patients, then immediately following a treatment fibrinolytics in 10 of them. The PE is confirmed by pulmonary angiography in 39 patients and embolectomy for the 2 patients who presented a mobile thrombus in the right atrium. A tricuspid insufficiency (TI) is almost always recorded by continuous Doppler: the systolic pulmonary artery pressure (sPAP) is calculated from the maximum velocity of the regurgitating tricuspid flow, using Bernouilli's equation. The correlation between Doppler sPAP and sPAP obtained by catheterization is: r = 0.95 (n = 34; p less than 0.001). A severe pulmonary hypertension, corresponding to a TI exceeding 3.5 m/s is related to a pulmonary migration occurring on a pathological heart. There is a satisfactory relationship between the elevation of the Doppler sPAP and the degree of pulmonary obstruction in the "Pe on healthy heart" population: r = 0.6 (n = 29; p less than 0.001). The dilated right ventricle observed on the sonogram (RV) is proportional to the severity of the angiographic image: correlation between the RV/LV ratio and the percentage of vascular obstruction is r = 0.73 (n = 27; p less than 0.001). The drop in the sPAP and the regression of the symptoms of pulmonary heart noted on CDS after fibrinolysis, correspond to a significant improvement of the pulmonary perfusion. The CDS seems to be absolutely necessary in PE because of the major and reliable informations it provides.

WHO's European member states look at quality assurance. Report on the technical discussions at the thirty-eighth session of the Regional Committee for Europe

This paper is the report on the technical discussions on "Quality assurance of health services" at the 38th session of the WHO Regional Committee for Europe, one of the activities aiming at achieving WHO's regional health for all target 31, which requests WHO's Member States to establish a quality assurance mechanism. Attended by national health authorities and experts in quality assurance, the technical discussions identified the European context for developing quality assurance and looked at national initiatives. Having agreed that the question is no more, "Is there a need for quality assurance of health services?" but, "How can it best be carried out?", the participants identified a range of quality assurance activities at national and international levels, including national strategies and financial incentives, criteria for clinical practice, information systems and coordination and management mechanisms. The report concludes with recommendations for Member States on, for example, inclusion of quality assurance in national health policies, dissemination of information, research on quality assurance, information systems and role of professional organizations.

[Comparative study of pulsed and continuous Doppler in the quantification of aortic insufficiency]

31 patients whose mean age was 61 +/- 29 yrs. presenting with aortic regurgitation (AR) benefited from cardiac catheterization which was preceded by Doppler ultrasound examination in a prospective study to compare the diagnostic contributions made by continuous vs pulsed wave techniques respectively in the quantitative assessment of AR, with reference to semi-quantitative angiographic evaluation. Pulsed Doppler analysis involves mapping of the left ventricle in two projections as well as the investigation of blood flow in the aortic isthmus using a suprasternal approach. Collection of continuous wave signals from the cardiac apex makes it possible to measure circulatory deceleration and the half-time of decrease in signal velocity and the protodiastolic pressure gradient. Our results corroborate the reliability of data obtained using continuous-wave Doppler technique in finding significant correlations for each parameter respectively: r' = 0.88 (p less than 0.001); r' = -0.81 (p less than 0.001); r' = -0.75 (p less than 0.001). Values determined by pulsed wave Doppler mapping of the left ventricle appear to be less satisfactory but are significant: r' = 0.68 (p less than 0.001) while measurement of end-diastolic blood flow recorded in the isthmus of the aorta is more highly correlated: r' = 0.84 (p less than 0.01), with the main disadvantage being its limited applicability to a small number of our patients (48%). We thus concluded that continuous-wave Doppler ultrasound is a better technique in the quantitative evaluation of AR, while recalling the essential additional value of pulsed-wave Doppler technique to localize the leakage and of ultrasound to assess its impact on the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

Cost of allogeneic bone marrow transplantation in four diseases

The cost of bone-marrow transplantation is compared in 4 diseases: acute myelogenous leukaemia, severe combined immunodeficiency, severe aplastic anaemia and chronic granulocytic leukaemia. Hospital cost components directly related to the clinical protocols applied are valorized. Results confirm the well-known fact that bone-marrow transplantation is a costly technique. The unit cost of a transplantation can vary from 1 to 2 between departments for the sole reason that patients treated are not suffering from the same illness. For one disease, the unit cost may vary from 1 to 2.7 when post-graft complications arise. Furthermore, in the health-care sector, as well as in every other economic sector, costs do not remain stable: they vary in time most especially when treatment protocols evolve. This type of cost information is the basis for management control systems without which physicians, hospital managers and health-care authorities cannot communicate effectively. In countries where health care is largely financed by the community, what is at stake is the future of advanced technologies in medicine.

[Validation of a method for measuring the area of aortic stenosis using only continuous Doppler. Value for the surveillance of transluminal aortic valvuloplasties]

Forty patients with aortic valve stenosis underwent continuous wave doppler-echocardiographic exploration followed by catheterization within 24 hours on average. Three methods of aortic functional area calculation, based on the continuity equation principle, were tried and compared with the haemodynamic data. The results of the reference equation (continuity through the whole systole) gave a correlation coefficient r = 0.77 with a standard error (SE) of 0.17 cm2. The continuity equation using only maximum velocity values was less satisfactory: r = 0.69; SE = 0.19 cm2. The simplified equation with an arbitrary 2 cm subaortic diameter and a subaortic velocity obtained by continuous wave doppler recording yielded results that were very similar to those of the reference equation: r = 0.78; SE = 0.16 cm2. It is suggested that this third equation should be used in the follow-up of transluminal aortic valvuloplasties, since its calculation is based only on aortic velocity, which reflects the degree of stenosis, and subaortic velocity, which indirectly reflects left ventricular function.

[Diagnostic and prognostic value of continuous Doppler in pulmonary embolism]

A prospective study of 18 patients admitted to hospital for acute pulmonary embolism confirmed the reliability of continuous wave cardiac doppler as a non-invasive method of evaluating systolic pulmonary artery pressures. These pressures were calculated by applying the simplified Bernoulli equation to the maximal velocity of regurgitant tricuspid flow and compared with the results of cardiac catheterisation and angiography, the percentage of vascular obstruction being assessed using Miller's index. The correlations between the two methods were good, r = 0.96; p less than 0.001, with a standard error of +/- 5.2 mmHg. The correlations between the velocity of tricuspid flow and the percentage of obstruction were less significant (r = 0.65; p less than 0.005) but improved when patients with pre-existing cardiopulmonary disease were excluded. This technique of non-invasive assessment of haemodynamic parameters also helps in evaluating the underlying pathology; tricuspid regurgitation with velocities greater than 3.5 m/s is associated with pre-existing chronic cor pulmonale, information of prognostic interest which would guide therapeutic management.

Examples of the influence of evaluation on health policy

Regulation strategies for controlling hospital costs are widely discussed today and medical technology assessment is one of these strategies. A Committee for Evaluation of the Diffusion of Innovative Technologies (CEDIT) was created in 1982 at the 'Assistance Publique de Paris', the most important health care institution in France. The CEDIT makes recommendations to the Director General on the use of new technologies. Since 1982, more than 50 medical technologies have been studied by the CEDIT: procedures such as plasmapheresis, bone marrow transplantation and percutaneous transluminal angioplasty; equipment such as lasers and the lithotriptor. The CEDIT helps planners who have to make difficult choices.

New high-yield synthesis of 18F-labelled 2-deoxy-2-fluoro-D-glucose

A new high-yield synthesis for the production of 18F-2-FDG has been developed by reacting 18F-labelled acetyl hypofluorite, prepared by in situ reaction of 18F-molecular fluorine with sodium acetate in glacial acetic acid, and tri-acetyl-D-glucal at room temperature. Molecular fluorine labelled with 18F was produced by a 20Ne(d, alpha) 18F reaction. 1,3,4,6-tri-O-acetyl-2-deoxy-2-fluoro-D-glucopyranose is extracted with methylene chloride, evaporated to dryness and hydrolyzed, yielding 98% radiochemically pure 18F-2-FDG. Overall radiochemical yield is about 24 +/- 3%. The specific activity of the final product at the end of synthesis is about 25.38 GBq/mmol (685 mCi/mmol). The synthesis time is approximately 60 min. The synthesis proves that small medical cyclotrons are able to produce 18F-molecular fluorine at the levels needed for the synthesis of 18F-2-FDG used in functional imaging with positron emission tomography.

Hypoxanthine: guanine phosphoribosyltransferase mutants in Saccharomyces cerevisiae

Yeast mutants lacking activity of the enzyme hypoxanthine:guanine phosphoribosyltransferase (H:G-PRT) have been isolated by selecting for resistance to 8-azaguanine in a strain carrying the wild type allele, ade4%, of the gene coding for amidophosphoribosyltransferase (PRPPAT), the first enzyme of de novo purine synthesis. The mutants excrete purines and are cross-resistant to 8-azaadenine. They are recessive and represent a single complementation group, designated hpt1. Ade4-su, a prototrophic allele of ade4 with reduced activity of PRPPAT, is epistatic to hpt1, suppressing purine excretion and resistance to azaadenine but not resistance to azaguanine. The genotype ade2hpt1 does not respond to hypoxanthine. Hpt1 complements and is not closely linked to the purine excreting mutants pur1 to pur5. Hpt1 and pur6, a regultory mutant of PRPPAT, are also unlinked but do not complement, suggesting a protein-protein interaction between H:G-PRT and PRPPAT. Mycophenolic acid (MPA), an inhibitor of de novo guanine nucleotide synthesis, inhibits the growth of hpt1 and hpt1+. Xanthine allows both genotypes to grow in the presence of MPA whereas guanine only allows growth of hpt1+. Activity of A-PRT, X-PRT and H:G-PRT is present in hpt+. Hpt1 lacks activity of H:G-PRT but has normal A-PRT and X-PRT.