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Biomedical subjects

W Rutishauser

Publications and source records attributed to W Rutishauser.

At least 37 records · Page 2Linked to original sources
PubMed1996

Applying the object paradigm to a centralized database for a cardiology division.

In order to master the overwhelming quantity of data produced by the different laboratories of our Cardiology Division, we are presently developing a centralized database. Our aim is to improve the quality of diagnoses and therapies by constituting patient centered medical files integrating logically the results of the results of the different examinations and allowing for a rapid access to the patient data. The database has to be accessible from an heterogeneous set of PC, MacIntoshes and UNIX workstations. It must have an ergonomic graphic user interface and generate reports which can be sent to the patient physician. It is well known that the requirements for a medical database make its conceptual analysis very difficult. As medical knowledge continually evolves, the examination protocols change and, therefore, the data sets have to be updated. The maintenance of classical databases is usually expensive because it requires specialized staff to alter the database structure and to adapt the user interface. To allow for flexibility, modularity, code reusability and reliability, the object paradigm was applied to a classical relational database. Thanks to the combination of both data structure and behavior in single entities, it is possible to build generic user interfaces which can be easily tailored to the needs of every laboratory of our Cardiology Division.

Cardiology↗
PubMed1996

Impact of a public campaign on pre-hospital delay in patients reporting chest pain.

OBJECTIVE: To decrease pre-hospital delay in patients with chest pain. DESIGN: Population based, prospective observational study. SETTING: A province of Switzerland with 380000 inhabitants. SUBJECTS: All 1337 patients who presented with chest pain to the emergency department of the Hôpital Cantonal Universitaire of Geneva during the 12 months of a multimedia public campaign, and the 1140 patients who came with similar symptoms during the 12 months before the campaign started. MAIN OUTCOME MEASURES: Pre-hospital time delay and number of patients admitted to the hospital for acute myocardial infarction (AMI) and unstable angina. RESULTS: Mean pre-hospital delay decreased from 7h 50 min before the campaign to 4 h 54 min during it, and median delay from 180 min to 155 min (P < 0.001). For patients with a final diagnosis of AMI, mean delay decreased from 9 h 10 min to 5 h 10 min and median delay from 195 min to 155 min (P < 0.002). Emergency department visits per week for AMI and unstable angina increased from 11.2 before the campaign to 13.2 during it (P < 0.02), with an increase to 27 (P < 0.01) during the first week of the campaign; visits per week for non-cardiac chest pain increased from 7.6 to 8.1 (P = NS) during the campaign, with an increase to 17 (P < 0.05) during its first week. CONCLUSIONS: Public campaigns may significantly reduce pre-hospital delay in patients with chest pain. Despite transient increases in emergency department visits for non-cardiac chest pain, such campaigns may significantly increase hospital visits for AMI and unstable angina and thus be cost effective.

Angina, Unstable↗
PubMed1996

Palmaz-Schatz Coronary Stent Implantation Without Intravascular Ultrasound and Without Subsequent Anticoagulation: Clinical Outcome.

OBJECTIVES: To determine the safety and efficacy of antiplatelet therapy alone in a selected group of patients following coronary stenting. BACKGROUND: Coronary stent implantation is an effective treatment for abrupt closure, and can also reduce the restenosis rate following percutaneous transluminal coronary angioplasty. However, anticoagulation therapy following stent implantation is associated with a significant incidence of vascular complications and subacute stent thrombosis. METHODS: Between February and November 1994 we implanted 62 Palmaz-Schatz stents in 50 patients with an optimal angiographic result following stent deployment. In these patients, intravascular ultrasound was not used, and a regimen of aspirin 100 mg daily indefinitely and ticlopidine 250 mg twice daily for 3 months was started without anticoagulation. RESULTS: Of these 50 patients (10 females : 40 males, mean age 63 +/- 12 years, LVEF 64 +/- 10%), 39 (78%) were stented for a suboptimal angiographic result post angioplasty, 2 (4%) received stents as a bailout procedure, and 9 (18%) were stented electively. Average hospital stay following stent implantation was 3.7 +/- 3.0 days. After a mean follow-up period of 140 +/- 70 days, there were no instances of stent occlusion, death, stroke, need for coronary bypass surgery, Q-wave myocardial infarction or femoral artery pseudoaneurysm. There was 1 case (2%) of significant puncture site hemorrhage. CONCLUSIONS: Immediate angiographic appearance after stent implantation can be used to define patients at low risk of stent thrombosis who do not require anticoagulation and can safely be discharged early from the hospital.

Journal Article↗
PubMed1995

[Asymptomatic ischemia--an important part of the spectrum of coronary disease].

Angina pectoris and asymptomatic myocardial ischemia are part of the spectrum of coronary heart disease. Not the presence or absence of angina determines the future of the patient, but repeated ischemia and the progression of the coronaropathy. This progression is neither linear with time, nor is the moment of plaque rupture foreseeable. Silent myocardial infarctions increase with age and are very frequent in diabetics. In patients without neuropathy but with asymptomatic myocardial ischemia the central pain threshold is higher than in patients with angina pectoris. The best noninvasive test for the detection, localization and estimation of extension of myocardial ischemia, be it pain-free or symptomatic, is 201-thallium scintigraphy, combined with the exercise ECG. The fight against all amendable cardiovascular risk factors and pharmacotherapy are the first steps, if asymptomatic myocardial ischemia is suspected. Augmented dyspnea on effort and rhythm disturbances are indicators of advanced multivessel heart disease. Under these circumstances coronary angiography is indicated, and further treatment should follow the generally accepted rules such as for patients with angina pectoris.

Aging↗
PubMed1995

Intra-arterial 90Y brachytherapy: preliminary dosimetric study using a specially modified angioplasty balloon.

PURPOSE: Irradiation has been shown to be effective in preventing restenosis after dilatation in human peripheral arteries. We have developed a dedicated system for coronary intraarterial irradiation using a 90Y pure beta-emitting source inside a specially modified angioplasty balloon. This paper presents a preliminary dosimetric evaluation of this system. METHODS AND MATERIALS: Specially fabricated titanium-covered and activated yttrium wires (outer diameter 0.32 mm) were used for these studies. Dosimetry was performed using small thermoluminescent dosimeters (TLDs) placed on the surface of the 2-cm long angioplasty balloons, inflated with contrast medium to a diameter of 2.5, 3, 3.5, and 4 mm. Radioactive 90Y wires were left in the inner balloon catheter and the surface dose rate was measured and extrapolated to 72 h after activation to allow a comparison between the values obtained. After observing the poor centering of the source within the standard angioplasty balloon, a new centering balloon was developed. A conventional balloon was subdivided into four evenly spaced interconnecting chambers, thus assuring adequate centering of the inner catheter. Thermoluminescent dosimetric measurements were performed with a 3.5 mm centering balloon to evaluate the homogeneity of the surface doses compared to those measured with the conventional balloon. RESULTS: Thermoluminescent dosimetric measurements using the standard balloons filled with contrast medium were plotted semilogarithmically as a function of distance from the balloon surface. The logarithms of the measured doses fit a straight line as a function of depth. The doses at 1 mm and 3 mm are approximately 50 and 10% of the surface dose, respectively. Due to the poor centering of the source in the conventional balloons, the dispersion and standard deviations (SDs) of the measured surface doses increased proportionally to the balloon diameter (SDs are 1.89, 5.52, 5.79, and 6.46 Gy for 2.5, 3, 3.5, and 4 mm balloon diameters, respectively). For the 3.5 mm centering and conventional balloons the respective mean, minimum, and maximum surface doses were 8.41 Gy (min. 7.26; max. 9.46) and 7.89 Gy (min. 2.18; max. 16.06) and their standard deviations were 0.66 and 5.79 Gy, respectively. CONCLUSIONS: Conventional angioplasty balloons cannot ensure a homogeneous dose delivery to an arterial wall with an intralumenal 90Y beta source. Preliminary dosimetric results using a modified centering balloon show that it permits improved surface dose distribution (axial and circumferential homogeneity), making it suitable for clinical applications.

Angioplasty, Balloon, Coronary↗
PubMed1995

High dose rate brachytherapy for prevention of restenosis after percutaneous transluminal coronary angioplasty: preliminary dosimetric tests of a new source presentation.

PURPOSE: Balloon dilatation of coronary artery stenosis has become a standard treatment of atherosclerotic heart disease. Restenosis due to excessive intimal cell proliferation, which subsequently occurs in 20-50% of patients, represents one of the major clinical problems in contemporary cardiology, and no satisfactory method for its prevention has thus far been found. Because modest doses of radiation have proved effective in preventing certain types of abnormal cellular proliferation resulting from surgical trauma, and brachytherapy has already been used successfully after dilation of peripheral arteries, development of a radioactive source suitable for coronary artery applications would be of great interest. METHODS AND MATERIALS: Nonradioactive flexible yttrium-89 wires (diameter of 0.15 and 0.26 mm) were activated within the thermal neutron flux of an experimental reactor. Standard angioplasty balloons (2 cm long, 2.5 mm in diameter when inflated) were inserted for dosimetry into a specially manufactured tissue equivalent phantom. Four wells, drilled perpendicular to the axis of the balloon, allowed for the insertion of thermal luminescent dosimeters (TLDs; 2 mm of diameter) and spacers. The angioplasty balloon was inflated with air or with contrast media. Radioactive yttrium-90 wires were left in the central lumen of the balloon for 2 min. Doses at the surface of the balloon, and at 1, 2, and 3 mm were determined from TLD readings. RESULTS: Doses obtained at the surface of the balloon, for a 2-min exposure for the 0.26 mm wire (balloon inflated with air) and the 0.15 mm wire (air or contrast), were 56.5 Gy, 17.8 Gy, 5.4 Gy, respectively. As expected for a beta emitter, the fall-off in dose as a function of depth was rapid. External irradiation from the beta source was negligible. CONCLUSIONS: Our experiments indicate that the dose rates attainable at the surface of the angioplasty balloon using this technique allow the doses necessary for the inhibition of intimal cell proliferation to be reached within a relatively short period of time. The thin yttrium-90 wires are very easy to handle, and their mechanical and radioactive properties are well suited to the requirements of the catheterization procedure.

Angioplasty, Balloon, Coronary↗
PubMed1995

Randomized evaluation of six French voda-type guiding catheters for left coronary artery balloon angioplasty.

In order to evaluate 6 French (6F) Voda-type guiding catheters for left coronary artery balloon angioplasty, we randomized the choice of the guiding catheter in 100 consecutive patients between a Voda (group 1, n = 50) and a Judkins or Amplatz curve (group 2) guiding catheter. Angioplasty success rate (98% for both), need for guiding catheter crossover exchange (2 in group 1 vs. 1 in group 2), fluoroscopy time, and volume of injected contrast were similar in both groups, but the operator's appreciation of good back-up support was better with the Voda-type guiding catheter (90% vs. 74%, P < 0.05). No complications attributed to the guiding catheter were noted in either group. Efficiency of the Voda-type guiding catheter appeared similar for both left anterior descending (n = 35, success rate 100%) and circumflex (n = 18, success rate 94%) coronary artery angioplasty. Voda-type guiding catheters are an efficient and safe approach to routine left coronary angioplasty. They appear to be as effective as a choice between a Judkins or an Amplatz configuration and could be of particular use when a double angioplasty of the left anterior descending and circumflex arteries is attempted during the same procedure.

Angioplasty, Balloon, Coronary↗
PubMed1995

Bailout coronary stenting with 6F guiding catheters for failed balloon angioplasty.

Between July 1992 and February 1994, we attempted bailout Palmaz-Schatz stent implantation through a 6F guiding catheter after 52 failed coronary balloon angioplasty procedures to reverse (14 [27%] cases) or prevent (38 [73%] cases) abrupt vessel closure. The stents or half-stents were manually crimped onto a monorail balloon catheter for delivery. Thirty-nine (75%) procedures involved a single stent, and 13 (25%) involved two or three stents. Technical success was achieved in 50 (96%) procedures, and clinical success without major complications was obtained in 45 (87%) cases. Target vessel occlusion was documented angiographically or suggested clinically in 2 (4%) cases. Two (4%) patients underwent semielective bypass surgery, and in 4 (8%) patients a non-Q-wave and in 1 (2%) a Q-wave myocardial infarction developed. There were no deaths. Major bleeding occurred in 2 patients: 1 had an important groin hematoma that was treated with local surgery followed by coronary bypass surgery, and one had macroscopic hematuria that required interruption of anticoagulation therapy on day 4. Three (6%) femoral pseudoaneurysms were diagnosed by ultrasound and could be obliterated by external compression alone. Bailout coronary stent implantation through 6F guiding catheters after failed balloon angioplasty is technically reliable, safe, and cost-efficient. As a consequence, use of 6F guiding catheters is a good option for a large majority of routine balloon angioplasty procedures.

Aged↗
PubMed1995

The Magnum wire for percutaneous coronary balloon angioplasty in 723 patients.

The experience of the use of the Magnum wire in a single center is reported. Percutaneous balloon coronary angioplasty, using the Magnum 0.021 inch wire, was attempted in 723 patients with 850 lesions; of these, 453 (53%) were chronic total occlusions and 50 (7%) recent occlusions of less than 24 hours (patients presenting with acute myocardial infarction). The overall technical success rate per lesion was 655/850 (77%). It was 255/280 (91%) for non-total lesions, 311/453 (69%) for chronic total occlusions, 53/67 (79%) for functional (TIMI grade I) occlusions, and 36/50 (72%) for recent occlusions. Clinical success was achieved in 196/232 patients (84%) with non-total lesions, in 292/436 (67%) with total chronic occlusions, in 49/65 (75%) with functional occlusions, and in 34/50 (68%) with recent occlusions. Complications (significant creatine kinase rise, new Q-wave infarction, need for coronary bypass surgery or in-hospital death) occurred in 7% (3% if patients presenting with unstable ischemic syndromes were excluded from the analysis). These data confirm that the use of the Magnum wire has success rates competitive with other systems both in setting of chronic total occlusion and in that of routine percutaneous transluminal coronary angioplasty.

Adult↗
PubMed1995

Acute embolic carotid occlusion after cardiac catheterization: effect of local intra-arterial urokinase thrombolysis.

A 64-year-old woman developed a severe embolic cerebral attack with total left hemiplegia approximately 30 hours after cardiac catheterization for mitral stenosis. She underwent intra-arterial thrombolysis of the right internal carotid artery four and one-half hours after the onset of neurologic deficit with subsequent recanalization of the occluded vessel and near complete neurologic recovery.

Acute Disease↗
PubMed1994

[Myocarditis mimicking myocardial infarct].

We describe 3 patients with an initial diagnosis of myocardial infarction, in whom a definitive diagnosis of myocarditis was subsequently established. All had precordial chest pain, electrocardiographic changes, elevated cardiac enzyme levels and regional wall motion abnormalities of the left ventricle compatible with myocardial infarction. During follow-up, all symptoms subsided and electrocardiographic tracings normalized. Regional wall motion abnormalities disappeared in two and persisted in one patient. These findings show that myocarditis may mimic myocardial infarction, and that the definitive diagnosis is generally established retrospectively.

Adult↗
PubMed1994

3D determination of the intravascular volume and flow of coronary arteries.

An angiographic method for measurement of absolute coronary blood flow in patients was developed. It is based on 3D-reconstruction of the left or right coronary tree from digitized biplane coronary cineangiograms. The apparatus is presently composed of a 35-mm cinefilm projector with video camera and a 512 x 512 x 8-bits image array processor controlled by a VAX-11/750 computer. First, the parameters of the two projections are determined in the form of two 4 x 3 matrices from a pair of cineframes showing a 4-cm cube bearing markers. The cube is filmed after the coronary injection, with unchanged geometric configuration. The coronary arteries of interest are then 3D-reconstructed from a pair of cineframes showing them fully opacified. This allows the intravascular volumes needed for flow determination to be computed. Preliminary measurements in 12 patients showed that flow values obtained angiographically in the left descending coronary artery correlate well with the values measured simultaneously by thermodilution in the great cardiac vein (Qangio = 0.83 x Qthermo + 16.1 ml, r = 0.87, n = 29).

Algorithms↗
PubMed1994

Heroin abuse and myocardial infarction.

A young woman developed an acute transmural infarction due to an acute thrombosis of the left anterior descending coronary artery, probably induced by a previous abuse of intravenous heroin.

Adult↗
PubMed1994

In-hospital monitoring after coronary angioplasty.

At the University Hospital of Geneva there are three postcoronary angioplasty monitoring levels: (A) intensive care unit; (B) optional ECG monitoring (cardiology unit); and (C) no monitoring (other unit). To assess the adequacy of patient monitoring after coronary angioplasty, we studied the clinical outcome of 200 consecutive patients undergoing coronary angioplasty at different monitoring levels. Thirty-nine patients (20%) were in level A. Their outcome was 1 death, 1 emergency bypass operation, and 7 acute myocardial infarcts. Ninety-six patients (48%) were in level B: no major complication, no transfer of monitoring level, and mean hospital stay 2.7 +/- 1.3 days. Sixty-five patients (32%) were in level C: 1 death, 2 elective bypass operations, 6 transfers to level A, and mean hospital stay 5.9 +/- 4.6 days. Electrocardiogram monitoring of 135 patients yielded 23 significant findings (17%), 22 of which occurred in patients with complicated or failed procedure. In the 122 patients with successful coronary angioplasty without angiographic visible local complications and without clinical symptoms at the end of the procedure, no significant arrhythmia or acute myocardial infarction was documented. For this type of patient, ECG monitoring is not a prerequisite after coronary angioplasty. Surveying all patients after coronary angioplasty in the coronary care unit would not significantly reduce complications. Aftercare in a cardiology unit results in a shorter hospital stay.

Adult↗
PubMed1994

Preliminary analysis of the effects of blood vessel movement on blood flow patterns in the coronary arteries.

Blood flow patterns are believed to be involved in the formation and progression of arterial diseases. It is possible that the normal physiologic movement of blood vessels during the cardiac cycle affects blood flow patterns significantly. For example, the contraction of the heart in systole and subsequent relaxation in diastole create movements of the coronary arteries, as evidenced in real-time angiography. The effects of this movement on coronary artery flow patterns have never been previously analyzed. This work was undertaken to provide a preliminary estimate of the importance of the effects of such physiologic movements on blood flow patterns in the coronary arteries. A Womersley-type solution was used to determine the effect of axial movement on the wall shear rate in a simplified model of the coronary arteries. The pulsatile pressure gradient was derived from previously published coronary artery flow waveforms. The axial movement function was obtained from a three-dimensional reconstruction of a biplanar coronary angiogram. Significant changes in wall shear rate were noted when the movement was taken into account. The maximum and minimum wall shear rates were 10 percent smaller and 107 percent larger in magnitude respectively, and the Oscillatory Shear Index (OSI) was doubled. Most of the changes in wall shear rate were observed in systole, when the pressure gradient is minimal and the movement is strongest. The results indicate that blood vessel movement during the cardiac cycle has a significant effect on hemodynamic phenomena which have been associated with the development of atherosclerosis.

Arteriosclerosis↗
PubMed1994

Lack of predictors of left ventricular functional improvement following coronary angioplasty.

Coronary angioplasty is frequently performed in a vessel with corresponding regional wall motion abnormalities. However, late improvement of left ventricular function remains questionable in many cases and is difficult to predict. A retrospective analysis of 115 patients with single vessel disease and corresponding abnormal regional left ventricular function at the time of coronary angioplasty was performed. All patients had control coronary angiography and a new contrast ventriculography 5.6 +/- 3.1 months later (range 0.8-11.8 months). Among those patients, 61 (53%) showed improvement of regional left ventricular function, which was not seen in the 54 (47%) others. Global ejection fraction increased significantly in the former group, whereas it remained unchanged in the later group. Before angioplasty, patients with and without improvement of systolic left ventricular function were indistinguishable in terms of history, medication, rest and stress electrocardiogram, and angiographic characteristics. During angioplasty, angina was more frequent (65% vs. 44%, p < 0.02) in patients with subsequent left ventricular functional improvement. At follow-up study, significant angiographic restenosis was more frequently encountered (68% vs. 43%, p < 0.05) in patients with no evidence of functional improvement. Thus, coronary angioplasty in a vessel responsible for left ventricular systolic dysfunction is followed in only half the cases by improvement of this parameter. No predictor of the functional outcome of the myocardium can be pointed out before the procedure is performed.

Aged↗