[Introduction of innovative high-risk medical devices in Europe: are clinical efficacy and safety guaranteed?]. / Mise sur le marché européen des dispositifs médicaux innovants à haut risque: l'efficacité clinique et la sécurité sont-elles garanties?

BACKGROUND: Innovative high-risk medical devices, such as new types of heart valves or hip prostheses, become available on the European market more rapidly than in USA. This is due to the European legislation allowing early marketing of innovative high-risk medical devices before high-quality clinical evidence is obtained from randomized controlled trials. METHODS: We studied the premarket clinical evaluation of innovative high-risk medical devices in Europe compared with the USA. We also discussed patient safety and the transparency of information. The literature and regulatory documents were checked. Representatives from industry, competent authorities, notified bodies, ethics committees, and health technology assessment agencies were consulted. RESULTS: In contrast to the US, there is no requirement in Europe to demonstrate the clinical efficacy of high-risk devices in the premarket phase. For the patient, this implies earlier access to innovative technology, but at the risk of potential safety issues. At this moment, European requirements for clinical studies are lower for medical devices than for drugs, and data from premarket clinical trials are scarce or remain unpublished. The European Medical Device Directives are currently being reworked. CONCLUSIONS: For innovative high-risk devices, and while awaiting a reworked Medical Device Directive, patient risk should be minimized by limiting the market introduction of novel high-risk devices with minimal clinical data to physicians with the necessary training and expertise. The new European legislation should require the premarket demonstration of clinical efficacy and safety, using a randomized controlled trial if possible, and a transparent clinical review, preferably centralized.

Pseudoaneurysm of the left ventricle following cardiac surgery. Report of 3 cases and review of the literature.

Three cases of pseudoaneurysms of the left ventricle after aneurysmectomy are presented. Pseudoaneurysm formation was evidently caused by infection in one case. In the 2 other cases the pathogenetic mechanism remains uncertain. Both local infection or a superimposed new myocardial infarction might have been responsible for pseudoaneurysm formation. In each instance diagnosis was suggested by one or more noninvasive techniques (echocardiography, isotopic ventriculography, CT-scanning) and confirmed by cineangiocardiography. Two patients were successfully reoperated while the third died shortly after surgery. Special attention is drawn to the pathogenetic mechanisms underlying postoperative pseudoaneurysm formation. Finally, the diagnostic value of non-invasive technique is discussed.

Treatment of life-threatening ventricular arrhythmias by a combination of antiarrhythmic drugs and right ventricular pacing.

Thirteen patients with intractable ventricular arrhythmias were studied; they underwent long-term treatment by a combination of antiarrhythmic drugs and ventricular pacing. Eleven patients had a history of tachycardia and two had torsade de pointes; eleven of thirteen had had cardioversion and/or defibrillation. Prior to permanent pacemaker implantation, temporary pacing in the VVI mode was used in combination with one or more of the following drugs: amiodarone, aprindine, digitalis, metoprolol, mexiletine, procainamide, pindolol, propranolol, or quinidine. Various pacing rates were tried; when permanent pacing was instituted, a unipolar system which was at least rate-programmable was used. Right ventricular VVI pacing, combined with drug therapy, was successful in ten of thirteen patients. Five of the ten patients are alive and free of arrhythmias after 78, 72, 72, 54, and 11 months, respectively. Although five patients died (after 60, 48, 30, 24, and 9 months, respectively), none of the deaths were related to arrhythmias. We suggest that in patients with ventricular arrhythmias refractory to conventional treatment, a therapeutic trial of right ventricular VVI pacing in combination with a drug regimen be used.

Partitioning of pulmonary impedance in excised human and canine lungs.

Partitioning of pulmonary resistance of 15 excised human and 5 canine lungs by means of a retrograde catheter demonstrated that the share of peripheral airways (with an ID of 2.4 mm or less) and of lung tissue in pulmonary resistance was markedly larger (44-96%) in humans than in dogs (41-59%). Similar percentages were found in patients with chronic obstructive pulmonary disease (COPD). The variations of resistance with volume during deflation and inflation of the lungs were due primarily to variations of peripheral resistance (Rp). The latter systematically increased at high and low lung volumes. Higher Rp values, with a more pronounced frequency dependence, were met in patients with COPD. A morphometrical study showed an inverse relationship between the value of Rp and the mean diameter of the terminal bronchioles, provided the airways density was taken into account.