EFOMP policy statement 17: The role and competences of medical physicists and medical physics experts in the different stages of a medical device life cycle.

MPPs are trained in the branches of physics associated with the practice of medicine. Possessing a solid scientific background and technical skills, MPPs are well suited to play a leading role within each stage of a medical device life cycle. The various stages of the life cycle of a medical device include establishment of requirements with use-case assessment, investment planning, procurement of medical devices, acceptance testing especially regarding safety and performance, quality management, effective and safe use and maintenance, user training, interfacing with IT systems, and safe decommissioning and removal of the medical devices.

The effect of electrical stimulation on leg muscle pump activity in spinal cord-injured and able-bodied individuals.

The purpose of this study was to examine the difference in: (1) effective muscle pump activity (MPA) between voluntary and electrically (ES) induced contractions in able-bodied subjects (ABS); and (2) ES-induced MPA between spinal cord-injured (SCI) individuals and ABS. MPA was measured as relative volume changes in the calf using strain-gauge plethysmography during repeated muscle contractions in the supine position while venous outflow was impeded by a thigh cuff inflated to a range of pressures. Ten SCI individuals and ten ABS participated in this study.

The postthrombotic syndrome in relation to venous hemodynamics, as measured by means of duplex scanning and strain-gauge plethysmography.

Purpose: Venous hemodynamics were evaluated in relation to the postthrombotic syndrome (PTS) 7 to 13 years after deep venous thrombosis (DVT).

Methods: The presence of flow, reflux, and compressibility of 1394 vein segments in 82 patients was assessed by means of duplex scanning. The venous outflow resistance was measured by means of strain-gauge plethysmography.

Venous duplex scanning of the leg: range, variability and reproducibility.

Despite the many studies on venous haemodynamics using duplex, only a few evaluated the normal values, variability and reproducibility. Therefore, the range and variability of venous diameter, compressibility, flow and reflux were measured. To obtain normal values, 42 healthy individuals (42 limbs, 714 vein segments) with no history of venous disease were scanned by duplex.

Deep venous thrombosis: a prospective 3-month follow-up using duplex scanning and strain-gauge plethysmography.

1. The purpose of the study was to evaluate the degree of thrombus regression, development of valvular insufficiency, impaired calf muscle pump function and clinical symptoms after a period of acute deep venous thrombosis. 2.

Changes in venous hemodynamics after renal transplantation.

To explain an occasionally observed transient swelling of the ipsilateral leg in renal transplant recipients in the absence of deep vein thrombosis, we took serial measurements of venous outflow resistance and duplex examinations of both legs. Fourteen recipients of a living related donor kidney graft were submitted to strain gauge plethysmography and duplex examination before transplantation and 1 and 6 weeks thereafter. Venous outflow resistance and venous flow were measured and the veins were assessed for thrombosis.

Duplex ultrasound in the hemodynamic evaluation of the late sequelae of deep venous thrombosis.

Purpose: The use of duplex ultrasound scanning to evaluate the hemodynamic outcome of deep venous thrombosis 7 to 13 years after the original diagnosis.

Methods: Duplex ultrasound was used to re-examine 1212 segments of vein from 72 patients (49 men, 23 women) with deep venous thrombosis previously diagnosed by means of phlebography to detect reflux and obstruction and evaluate flow; 611 segments were initially thrombosed and 601 segments were open. To define reflux, reversed flow in 31 healthy persons was measured.

Doppler spectrum analysis versus direct femoral artery pressure measurement for rapid assessment of aortoiliac obstruction.

Adequate patient selection is required to limit the clinical workload and improve the cost-effectiveness of noninvasive hemodynamic evaluation of the aortoiliac system. In a prospective blinded fashion the traditional invasive technique of direct femoral artery pressure measurements and the computerized Doppler spectrum analysis of blood flow velocities in the common femoral artery were studied. Both tests for rapid assessment of aortoiliac obstruction were compared with duplex ultrasonographic imaging, using a peak systolic velocity ratio of 2.

Clinical and haemodynamic sequelae of deep venous thrombosis: retrospective evaluation after 7-13 years.

1. In contrast to the extensive documentation on diagnosis and treatment of deep venous thrombosis (DVT), information about long-term complications, like the post-thrombotic syndrome (PTS), is scarce. Most studies report on clinical examination only, whereas adequate haemodynamic investigation is lacking.

Decreased ankle/brachial indices in relation to morbidity and mortality in patients with peripheral arterial disease.

To determine the relationship between ankle/brachial indices (ABIs) and morbidity and mortality in patients with peripheral arterial disease (PAD), a historical cohort study was performed. A total of 154 patients who had undergone noninvasive arterial assessment of the lower extremities in 1989 and 1990 were selected for this purpose. Selection criteria were age > 40 years at the time of investigation, a resting ABI < 0.

Effect of apheresis of low-density lipoprotein on peripheral vascular disease in hypercholesterolemic patients with coronary artery disease.

Background: Apheresis of low-density lipoprotein (LDL) is an effective lipid-lowering treatment in hypercholesterolemic patients who have coronary artery disease and are refractory to drugs. More aggressive lipid-lowering therapy may further slow the progression of atherosclerosis.

Objective: To compare the effect of LDL apheresis and simvastatin therapy with the effect of simvastatin therapy alone on the progression of peripheral vascular disease.

Validation of the supine venous pump function test: a new non-invasive tool in the assessment of deep venous insufficiency.

1. A new non-invasive test was developed to assess calf muscle pump function: the supine venous pump function test. The technique uses strain-gauge plethysmography and is performed in the supine position.

Doppler spectrum analysis in the differential diagnosis of renal transplant dysfunction.

Cyclosporin A (CyA) nephrotoxicity and rejection of a renal allograft each demands a specific therapy. This study was designed to establish the capability of Doppler spectrum analysis to diagnose either one of these causes during renal dysfunction. Between October 1989 and October 1991 we performed echo-Doppler examinations in 209 renal transplant recipients on a routine basis during the first three months after transplantation.

Diagnosis of deep vein thrombosis, an overview.

Because clinical signs and symptoms are unreliable the diagnosis of deep vein thrombosis (DVT) should be objectified. Advantages and disadvantages of contrast venography, plethysmography, ultrasound techniques, fibrinogen leg scanning, computer-assisted tomography, magnetic resonance imaging and blood tests are discussed. In patients with a first event of suspected DVT non-invasive methods like serial plethysmography or ultrasound testing are sensitive and specific enough to make a treatment decision.

The prevalence of peripheral vascular disease in familial hypercholesterolaemia.

Objectives: In patients with familial hypercholesterolaemia (FH), the prevalence of haemodynamically significant peripheral vascular disease (PVD) was measured in relation to lipoproteins, general risk factors and the presence of coronary artery disease (CAD).

Design: A case control study.

Setting: The outpatient lipid clinic of a university hospital (tertiary referral centre).

Echo-Doppler diagnosis of renal allograft artery stenosis.

For the diagnosis of allograft artery stenosis in recipients of a renal transplant with hypertension a noninvasive investigation such as echo-Doppler is preferable to invasive methods such as angiography. Therefore we analyzed our experience with echo-Doppler diagnosis of renal allograft artery stenosis. In 131 renal transplant recipients with hypertension echo-Doppler examinations were performed.

Properties of the venous vascular system in the lower extremities of individuals with paraplegia.

The purpose of this study was to examine the properties of the venous vascular system in the lower extremities of individuals with long-standing paraplegia (PP). The venous volume variations (VVV), the venous capacity (VC), the venous emptying rate (VER) and the venous flow resistance (VFR) were measured in the left calf of 14 male PP and 12 male able-bodied subjects (ABS) by means of strain-gauge occlusion plethysmography. VVV and VC were significantly lower in PP compared to ABS, -45% and -50% respectively.

Doppler spectrum analysis to diagnose rejection during posttransplant acute renal failure.

During posttransplant acute renal failure (ARF), the diagnosis of allograft rejection constitutes a major problem. We evaluated the value of Doppler ultrasonography in identifying grafts at risk of rejection during ARF. In 184 recipients of a renal allograft, Doppler examinations were performed on the first and fifth postoperative day.

Importance of the coronary collateral circulation for the distribution of anterograde and retrograde delivered cardioplegic solution in aortocoronary bypass surgery: a haemodynamic study.

The importance of coronary collateral circulation for homogeneous distribution of anterograde and retrograde delivery of cardioplegia was evaluated in 36 patients undergoing myocardial revascularization. All patients had three-vessel coronary artery disease, with a stenosis of the right coronary artery of at least 80%. The patients were randomized into two groups: group A (n = 19) received anterograde delivered cardioplegic solution and group B (n = 17) received retrograde.

Sternal closure: comparison of two techniques.

A clinical trial was performed to evaluate sternal closure with the controlled tension osteosynthesis system and closure with twisted stainless steel wires. Some 451 consecutive patients who underwent isolated coronary bypass surgery between January 1991 and December 1991 were subdivided into three groups. Patients in group A (94 patients) and group B (98 patients) were all operated on by one surgeon, to reduce variability before, at the time of and after surgery, which might influence sternal wound healing.

Haemodynamic evaluation of retrograde versus anterograde delivery of cardioplegic solution in aortic valve replacement.

A total of 44 patients undergoing isolated aortic valve replacement received either anterograde (20 patients) or retrograde (24 patients), cold St Thomas's Hospital cardioplegia. The patients were similar with respect to age, sex, left ventricular ejection fraction, left ventricular-aortic pressure gradient, cross-clamping time and mean dose of cardioplegia. After surgery, there were no differences in enzyme release, low cardiac output syndrome, rhythm disturbances or clinical outcome between the two groups.

Iliac artery stenosis after kidney transplantation.

In human kidney transplantation hypertension and renal dysfunction are common complications. Diagnosis of vascular involvement may frequently be necessary. Although iliac artery stenosis is a rare complication after renal transplantation, it can be the cause of hypertension and renal dysfunction.

Computer simulations in comparison with in vivo measurements of nifedipine-induced changes in renal allograft hemodynamics.

Analysis of Doppler spectrum waveforms is increasingly used in the differential diagnosis of human renal allograft dysfunction. The physiologic interpretation of changes in Doppler spectra obtained from renal allografts, however, remains a major problem. Computer simulation models of the renal circulation may provide insight into the physiologic mechanisms responsible for changes in Doppler spectrum characteristics.