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Stefan Osswald

Publications and source records attributed to Stefan Osswald.

28 records · Page 2Linked to original sources
PubMed2004

Cost-effectiveness of invasive versus medical management of elderly patients with chronic symptomatic coronary artery disease. Findings of the randomized trial of invasive versus medical therapy in elderly patients with chronic angina (TIME).

AIM: To compare benefits and costs of invasive versus medical management in elderly patients with chronic angina. METHODS AND RESULTS: In a predefined subgroup of 188 patients of the Trial of Invasive versus Medical therapy in Elderly patients with chronic angina (TIME), one-year benefits were assessed as freedom from major events and improvements in symptoms and quality of live. Costs were determined as one-year costs of resource utilisation. Invasive patients had higher 30-day, but lower months 2-12 hospital and intervention costs than medical patients, resulting in somewhat higher one-year costs for invasive management (p=0.08). However, billing data available for a subgroup of patients showed higher practitioner's charges in the medical patients (adjusted p=0.0015). Incremental costs to prevent one major event by invasive management averaged CHF 10100 (95% CI: -800 to 28300) or 6965, ranging from average CHF 5100 (euro 3515) to CHF 11600 (euro 8000) in a best, compared to a worst, case scenario. CONCLUSIONS: Early increased costs of revascularization in invasive patients were balanced after one year by increased practitioners' charges and symptom-driven late revascularizations in medical patients. Therefore, the invasive strategy with improved clinical effectiveness at only marginally higher costs as medical management was cost-effective. Costs should not be an argument against invasive management of elderly patients with chronic angina.

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PubMed2004

Prognostic value of stress testing in patients over 75 years of age with chronic angina.

STUDY OBJECTIVES: To define the prognostic value of stress testing (STRT) in patients >or= 75 years of age. DESIGN: Multicenter prospective randomized trial. SETTING: Tertiary care centers. PATIENTS: Two hundred ninety-two patients of the Trial of Invasive vs Medical Treatment of Elderly Patients aged >or= 75 years with chronic angina despite receiving two or more antianginal drugs were prospectively observed for 1 year. INTERVENTION: STRT (88% exercise ECG; 12% pharmacologic stress imaging) was performed if possible, and ischemia was diagnosed using current guidelines. Death for any reason and nonfatal myocardial infarction were outcome events. RESULTS: Patients who could perform STRT (148 patients) were younger, had a lower risk profile, received less medication, and had less severe angina than patients who could not perform STRT (144 patients). The 1-year mortality rate was only 1.4% in patients with negative STRT results (72 patients) compared to 5.3% in patients with positive STRT results (76 patients) and 13.7% in patients who had not undergone STRT due to unstable symptoms (95 patients). The corresponding 1-year rates of death/infarction were 2.8%, 15.8%, and 26.3%, respectively. After adjustment for baseline differences, mortality rates were no longer significantly different. However, compared to patients with negative STRT results, infarction and death/infarction rates remained higher in patients with provocable ischemia (hazard ratio [HR], 8.9 [p = 0.04]; HR, 6.1 [p = 0.02], respectively) and in patients without STRT due to unstable angina (HR, 11.8 [p = 0.02]; HR, 8.6 [p =.004], respectively). CONCLUSIONS: STRT in elderly patients is feasible and provides important prognostic information for their future management. Patients with negative STRT results after receiving therapy have a good prognosis, and their conditions may be managed conservatively.

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PubMed2003

Outcome of elderly patients with chronic symptomatic coronary artery disease with an invasive vs optimized medical treatment strategy: one-year results of the randomized TIME trial.

CONTEXT: The risk-benefit ratio of invasive vs medical management of elderly patients with symptomatic chronic coronary artery disease (CAD) is unclear. The Trial of Invasive versus Medical therapy in Elderly patients (TIME) recently showed early benefits in quality of life from invasive therapy in patients aged 75 years or older, although with a certain excess in mortality. OBJECTIVE: To assess the long-term value of invasive vs medical management of chronic CAD in elderly adults in terms of quality of life and prevention of major adverse cardiac events. DESIGN: One-year follow-up analysis of TIME, a prospective randomized trial with enrollment between February 1996 and November 2000. SETTING AND PARTICIPANTS: A total of 282 patients with Canadian Cardiac Society class 2 or higher angina despite treatment with 2 or more anti-anginal drugs who survived for the first 6 months after enrollment in TIME (mean age, 80 years [range, 75-91 years]; 42% women), enrolled at 14 centers in Switzerland. INTERVENTIONS: Participants were randomly assigned to undergo coronary angiography followed by revascularization (if feasible) (n = 140 surviving 6 months) or to receive optimized medical therapy (n = 142 surviving 6 months). MAIN OUTCOME MEASURES: Quality of life, assessed by standardized questionnaire; major adverse cardiac events (death, nonfatal myocardial infarction, or hospitalization for acute coronary syndrome) after 1 year. RESULTS: After 1 year, improvements in angina and quality of life persisted for both therapies compared with baseline, but the early difference favoring invasive therapy disappeared. Among invasive therapy patients, later hospitalization with revascularization was much less likely (10% vs 46%; hazard ratio [HR], 0.19; 95% confidence interval [CI], 0.11-0.32; P<.001). However, 1-year mortality (11.1% for invasive; 8.1% for medical; HR, 1.51; 95% CI, 0.72-3.16; P =.28) and death or nonfatal myocardial infarction rates (17.0% for invasive; 19.6% for medical; HR, 0.90; 95% CI, 0.53-1.53; P =.71) were not significantly different. Overall major adverse cardiac event rates were higher for medical patients after 6 months (49.3% vs 19.0% for invasive; P<.001), a difference which increased to 64.2% vs 25.5% after 12 months (P<.001). CONCLUSIONS: In contrast with differences in early results, 1-year outcomes in elderly patients with chronic angina are similar with regard to symptoms, quality of life, and death or nonfatal infarction with invasive vs optimized medical strategies based on this intention-to-treat analysis. The invasive approach carries an early intervention risk, while medical management poses an almost 50% chance of later hospitalization and revascularization.

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PubMed2003

Arrhythmogenic right ventricular cardiomyopathy: diagnostic and prognostic value of the cardiac MRI in relation to arrhythmia-free survival.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a potentially fatal disease, which is often difficult to diagnose. As a non-invasive test cardiac magnetic resonance imaging (CMR) has become an important tool in establishing the diagnosis. The aim of this study was to evaluate the diagnostic and prognostic value of CMR in patients with suspected ARVC and to assess the long-term outcome of patients with CMR-diagnosed ARVC. Thirty-six patients with suspected ARVC (26 male, 10 female, median age 41 years) underwent non-invasive and invasive clinical tests as gold standard for ARVC diagnosis. ARVC was clinically diagnosed in 19 patients and excluded in 17 patients. Both groups underwent CMR, and diagnosis was confirmed by CMR in 16/18 patients with clinically diagnosed ARVC (sensitivity 89%), and correctly excluded in 14/17 of patients with clinically excluded ARVC (specificity 82%). This result indicates a positive predictive value of the CMR of 84%, and a negative predictive value of 88%, respectively (p < 0.0001). Using a scoring system, multiple CMR parameters were compared in the two groups in regard of the clinical diagnosis. By univariate analysis, right ventricular fatty tissue infiltration (p = 0.0003) was predictive for diagnosis. Compared by outcome, 37% of patients with clinically and by CMR-diagnosed ARVC had an arrhythmic event during a mean follow-up of 16 +/- 11 months. These data suggest that CMR is a highly sensitive and specific method to diagnose or exclude ARVC, and thus, has an important prognostic impact on predicting arrhythmia free survival.

Adult↗
PubMed2003

Rate response of a closed-loop stimulation pacing system to changing preload and afterload conditions.

Closed-loop stimulation (CLS) is a new sensor concept for rate adaptive pacing measuring changes in the unipolar right ventricular impedance, which correlates to changes of the right ventricular contractility and reflects the autonomic nervous innervation of the heart. Some patients do not tolerate the CLS mode because of inappropriate tachycardia, mainly related to postural changes. This study tested if the rate response of the CLS sensor is influenced not only by myocardial contractility but also by rapid changes in right ventricular filling. In 12 patients (10 men, median age 77 years) with a Biotronik Inos(2)-CLS DDDR pacemaker and 14 controls (13 men, median age 59 years) head-up tilt and handgrip testing was performed to provoke rapid changes in pre- and afterload. Tilting the pacemaker patients resulted in a nonphysiological steep increase of the sensor rate (increase >20 beats/min, peak after 1 minute, return to baseline within 2-3 minutes), which was significantly different from the control group, showing only a slight rise in intrinsic heart rate immediately after tilting. Simultaneously to the rapid increase in sensor rate, the pacemaker patients showed a marked orthostatic decline of systolic blood pressure. During handgripping, heart rate and blood pressure curves were similar in both groups. In patients with this CLS pacemaker, rapid preload reduction during head-up tilting caused an overshooting sensor rate increase, reproducing the authors' clinical observation of postural pacemaker tachycardia in some patients. Consequently, they concluded that the rate response of the CLS pacing system can be inappropriately influenced by rapid shifts of blood volume, affecting right ventricular filling.

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PubMed2002

European clinical experience with a dual chamber single pass sensing and pacing defibrillation lead.

Dual chamber ICDs are increasingly implanted nowadays, mainly to improve discrimination between supraventricular and ventricular arrhythmias but also to maintain AV synchrony in patients with bradycardia. The aim of this study was to investigate a new single pass right ventricular defibrillation lead capable of true bipolar sensing and pacing in the right atrium and integrated bipolar sensing and pacing in the right ventricle. The performance of the lead was evaluated in 57 patients (age 61 +/- 12 years; New York Heart Association 1.9 +/- 0.6, left ventricular ejection fraction 0.38 +/- 0.15) at implant, at prehospital discharge, and during a 1-year follow-up. Sensing and pacing behavior of the lead was evaluated in six different body positions. In four patients, no stable position of the atrial electrode could intraoperatively be found. The intraoperative atrial sensing was 2.3 +/- 1.6 mV and the atrial pacing threshold 0.8 +/- 0.5 V at 0.5 ms. At follow-up, the atrial sensing ranged from 1.5 mV to 2.2 mV and the atrial pacing threshold product from 0.8 to 1.7 V/ms. In 11 patients, an intermittent atrial sensing problem and in 24 patients an atrial pacing dysfunction were observed in at least one body position. In 565 episodes, a sensitivity of 100% and a specificity of 96.5% were found for ventricular arrhythmias. In conclusion, this single pass defibrillation lead performed well as a VDD lead and for dual chamber arrhythmia discrimination. However, loss of atrial capture in 45% of patients preclude its use in patients depending on atrial pacing.

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PubMed2002

Late potential analysis: is a mathematically-derived X,Y,Z lead system comparable to a true orthogonal X,Y,Z lead system?

BACKGROUND: Analysis of ventricular late potentials (LP) with signal-averaged ECG (SAECG) using three bipolar, orthogonal X,Y, Z leads is a validated method of risk-stratification in patients prone to ventricular tachycardia. The aim of this study was to validate a ECG system, which allows LP analysis using X,Y, Z leads mathematically derived from the standard 12-lead ECG. METHODS AND RESULTS: In 36 patients (age 56 +/- 12 years, coronary artery disease 71%, LVEF 46 +/- 14%) with known or suspected ventricular tachyarrhythmia, two consecutive SAECGs were recorded, one with mathematically derived and another one with true X,Y, Z leads. Time domain measurements with these different lead systems were compared using linear regression analysis and "Bland-Altman" plots. Correlation was good (r = 0.92) for the filtered QRS complex duration, but poor for the terminal QRS amplitude (RMS) and duration (LAS) criteria (r = 0.66 and 0.61, respectively; P < 0.0001). Defining LPS as present if at least two of the three time domain criteria were abnormal, the result matched in 28 (78%), but differed in 8 (22%) patients. CONCLUSION: SAECG using X,Y, Z leads mathematically derived from the standard 12-lead ECG compared to true bipolar X,Y, Z leads show a close correlation in filtered QRS duration, but can differ considerably in the other time domain measurements, resulting in different interpretation of LP analysis in 22%. Therefore, SAECG registration should currently be performed with true X,Y, Z leads, until the accuracy of other approaches is validated.

Adult↗
PubMedDate not supplied

Incremental cost-effectiveness of drug-eluting stents compared with a third-generation bare-metal stent in a real-world setting: randomised Basel Stent Kosten Effektivitäts Trial (BASKET).

BACKGROUND: No prospective trial-based data are available for incremental cost-effectiveness of drug-eluting stents (DES) compared with bare-metal stents (BMS) in unselected patients, as treated in everyday practice. METHODS: The Basel stent cost-effectiveness trial (BASKET) included 826 consecutive patients treated with angioplasty and stenting for 1281 de-novo lesions, irrespective of indication for angioplasty. Patients were randomised to one of two DES (Cypher, n=264; Taxus, n=281) or to a cobalt-chromium-based BMS (Vision, n=281) and followed up for 6 months for occurrence of major adverse cardiac events and costs. Analysis was by intention-to-treat. The primary endpoint was cost-effectiveness after 6 months, with effectiveness defined as reduction of major adverse cardiac events. FINDINGS: Cardiac death, myocardial infarction, or target vessel revascularisation occurred in 39 of 544 (7.2%) patients with DES and 34 of 280 (12.1%) with BMS (odds ratio 0.56, 95% CI 0.35-0.91; p=0.02), without significant differences between the two DES. Total costs at 6 months were higher with DES (mean 10,544, SD 6849) than with BMS (9639, 9067; p<0.0001); higher stent costs of DES were not compensated for by lower follow-up costs. Incremental cost-effectiveness ratio of DES compared with BMS to avoid one major event was 18,311, and costs per quality-adjusted life-year gained were more than 50 000. Subgroup analyses showed that DES were more cost-effective for elderly patients in specific high-risk groups. INTERPRETATION: In a real-world setting, use of DES in all patients is less cost effective than in studies with selected patients. Use of these stents could be restricted to patients in high-risk groups.

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