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Biomedical subjects

M G Hunink

Publications and source records attributed to M G Hunink.

At least 37 records · Page 2Linked to original sources
PubMed1998

Randomised comparison of primary stent placement versus primary angioplasty followed by selective stent placement in patients with iliac-artery occlusive disease. Dutch Iliac Stent Trial Study Group.

BACKGROUND: Percutaneous transluminal angioplasty (PTA) is a safe, simple, and successful treatment for intermittent claudication caused by iliac-artery occlusive disease. Primary stent placement has been proposed as more effective than PTA. We compared the technical results and clinical outcomes of two treatment strategies-primary placement of a stent across the stenotic segment of the iliac artery, or primary PTA followed by selective stent placement when haemodynamic results were inadequate. METHODS: We randomly assigned 279 patients with intermittent claudication, recruited from departments of vascular surgery, either to direct stent placement (group I, n=143) or primary angioplasty (group II, n=136), with subsequent stent placement in case of a residual mean pressure gradient greater than 10 mm Hg across the treated site. The main inclusion criterion was intermittent claudication on the basis of iliac-artery stenosis of more than 50%, proven by angiography. All patients had a clinical assessment before intervention and at 3, 12, and 24 months. Clinical success was defined as improvement of at least one clinical category. Secondary endpoints were initial technical results, procedural complications, cumulative patency as assessed by duplex ultrasonography, and quality of life. FINDINGS: In group II, selective stent placement was done in 59 (43%) of the 136 patients. The mean follow-up was 9.3 months (range 3-24). Initial haemodynamic success and complication rates were 119 (81%) of 149 limbs and 6 (4%) of 143 limbs (group I) versus 103 (82%) of 126 limbs and 10 (7%) of 136 limbs (group II), respectively. Clinical success rates at 2 years were 29 (78%) of 37 patients and 26 (77%) of 34 patients in groups I and II, respectively (p=0.6); however, 43% and 35% of the patients, respectively, still had symptoms. Quality of life improved significantly after intervention (p<0.05) but we found no difference between the groups during follow-up. 2-year cumulative patency rates were similar at 71% versus 70% (p=0.2), respectively, as were reintervention rates at 7% versus 4%, respectively (95% CI -2% to 9%). INTERPRETATION: There were no substantial differences in technical results and clinical outcomes of the two treatment strategies both at short-term and long-term follow-up. Since angioplasty followed by selective stent placement is less expensive than direct placement of a stent, the former seems to be the treatment of choice for lifestyle-limiting intermittent claudication caused by iliac artery occlusive disease.

Adult↗
PubMed1998

Cost-identification analysis of revascularization procedures on patients with peripheral arterial occlusive disease.

OBJECTIVE: To determine average total in-hospital costs of various revascularization procedures for peripheral arterial occlusive disease; to examine the effect of procedure-related complications and patient characteristics on these costs; and to examine whether costs have changed over time. METHODS: We collected cost data on all admissions involving one revascularization procedure for peripheral arterial occlusive disease at the Brigham and Women's hospital from 1990 through 1995 (n = 583). The main outcome measures were total costs per admission in 1995 US dollars and length of stay in days. RESULTS: For each of 12 different procedures identified, total costs per admission varied considerably. Multiple linear regression analysis was performed to determine the effect of local and systemic complications and of patient characteristics on total in-hospital costs per admission. The additional cost incurred for fatal systemic complications was $11,675 (P = .004) and for nonfatal systemic complications was $9345 (P < .001). The results demonstrated significant additional costs with management of critical ischemia versus intermittent claudication ($4478, P < .001), presence of coronary artery disease ($1287, P = .05), female sex ($1461, P = .03), and advanced age ($1345, P = .02). No statistically significant changes over time were demonstrated. CONCLUSION: Total in-hospital costs per admission for peripheral revascularization procedures are highly variable and significantly increased by procedure-related complications, advanced age, female sex, management of critical ischemia, and presence of coronary artery disease.

Adult↗
PubMed1998

Contralateral symptoms after unilateral intervention for peripheral occlusive disease.

OBJECTIVE: The objectives of this study were (1) to determine the incidence of contralateral symptoms in patients with a unilateral intervention for peripheral arterial occlusive disease and (2) to identify characteristics that predict these symptoms. SUBJECTS AND SETTING: We included patients who had a unilateral surgical or percutaneous intervention for peripheral arterial occlusive disease at the Brigham and Women's Hospital (Boston) between 1990 and 1995 (n = 532). MAIN OUTCOME MEASURE: The main outcome measure was the first occurrence of contralateral critical ischemia or intermittent claudication. RESULTS: The annual incidence rate of contralateral critical ischemia was considerable, ranging from 3.3% to 8.3% during the first 4 years after the initial ipsilateral intervention. The annual incidence rate of contralateral critical ischemia and claudication combined varied from 7.7% to 21.3%. Cox regression analysis indicated that the initial ipsilateral symptoms and the initial contralateral ankle/brachial index can be used to predict the occurrence of contralateral symptoms. After correction was done for these two variables, we found no statistically significant effects for other factors including age, sex, diabetes, smoking, antihypertensive medication, history of coronary artery disease, the type of intervention, and the arterial level of the intervention. CONCLUSIONS: The results of our analysis emphasize that peripheral arterial occlusive disease is essentially a two-limb problem. Especially patients with previous ipsilateral critical ischemia and patients with a poor initial contralateral ankle/brachial index have a high risk for contralateral critical ischemia.

Adult↗
PubMed1998

Intermittent claudication: symptom severity versus health values.

OBJECTIVE: The objective of this study was to obtain health values from patients with intermittent claudication with five different instruments and to study the construct validity of these measures of health-related quality of life by examining their relation with symptom severity. METHODS: We included all patients with intermittent claudication who participated in an exercise program of the Department of Internal Medicine at our university hospital (n = 92). Health value instruments included the verbal rating scale, time trade-off, standard gamble, EuroQol, and the Health Utilities Index (Mark III). Symptom-free walking distance was used as a measure of symptom severity. RESULTS: For all instruments the average health values in groups of patients with a symptom-free walking distance < or = 150 m were lower than the average values in patients with a greater walk distance, but the differences for the time trade-off and the standard gamble were small, and only the differences for the verbal rating scale and the EuroQol were statistically significant. At the individual patient level considerable heterogeneity was seen, and the statistical association of the symptom-free walking distance with health values varied from poor to moderate (Spearman rank correlations, 0.03 to 0.48; p values, 0.003 to 0.78). CONCLUSION: At least for the verbal rating scale and the EuroQol, the results of our study provide evidence of the validity of the various health value instruments in a population of patients with peripheral arterial occlusive disease.

Aged↗
PubMed1998

Heterogeneity in the relationship between the time tradeoff and Short Form-36 for HIV-infected and primary care patients.

OBJECTIVES: Evidence in the literature suggests that the overall correlation between descriptive and valuational measures of health are weak to moderate. In this study, the relationship between descriptive health status measures, obtained using the Short-Form 36, and health values, measured with the time tradeoff, was explored. METHODS: Two groups of patients matched for age and gender were interviewed. One group comprised 139 human immunodeficiency virus (HIV)-infected patients; the other group comprised 124 primary care patients. The relationship between the SF-36 and the time tradeoff was estimated, assuming homogeneity across patients, using multiple regression analysis. Subsequently, the relationship was examined assuming heterogeneity across patients and using the expectation maximization algorithm in a maximum likelihood context (latent class analysis). RESULTS: Four classes, representing 47%, 13%, 8%, and 32% of the population, respectively, were found. The overall percentage of variation explained under the assumption of a homogeneous relationship was only 33% as compared with 85% when heterogeneity was accounted for. Only three characteristics (educational level, employment status, and the SF-36 social functioning score) sufficed to generate a nearly perfect classification of the patients. CONCLUSIONS: Heterogeneity across subjects should be taken into account in describing the relationship between health values and health status dimensions.

Attitude to Health↗
PubMed1998

Iliac arterial occlusive disease: cost-effectiveness analysis of stent placement versus percutaneous transluminal angioplasty. Dutch Iliac Stent Trial Study Group.

PURPOSE: To evaluate the relative benefits and cost-effectiveness of treating iliac arterial occlusive disease with various interventions. MATERIALS AND METHODS: Cost-effectiveness was analyzed in a hypothetical cohort of patients with intermittent claudication caused by an iliac arterial stenosis. Primary stent placement, percutaneous transluminal angioplasty (PTA), and PTA with selective stent placement were analyzed. Reduction in the risk of failure after primary stent placement versus that after PTA with selective stent placement, quality of life, and cost data were derived from results of a randomized, controlled trail. Complication rates, patency results, and the reduction in risk of failure were derived from a published meta-analysis. RESULTS: PTA with selective stent placement yielded equivalent complication rates, patency results, and quality-of-life outcomes compared with those of primary stent placement, and the latter cost +957 less (95% confidence interval = +726, +1,188). PTA with selective stent placement was more expensive than PTA alone but yielded higher patency results (relative risk of long-term failure, 0.61; 95% confidence interval = 0.49, 0.75) and quality-adjusted life expectancy (0.2 quality-adjusted life year [QALY] gained) and had an incremental cost-effectiveness ratio of less than +20,000 per QALY gained. CONCLUSION: PTA with selective stent placement is a cost-effective treatment strategy compared with primary stent placement or PTA alone in the treatment of intermittent claudication caused by an iliac arterial stenosis.

Angioplasty, Balloon↗
PubMed1997

The recent decline in mortality from coronary heart disease, 1980-1990. The effect of secular trends in risk factors and treatment.

OBJECTIVE: To examine whether secular trends in risk factor levels and improvements in treatment can account for the observed decline in coronary heart disease mortality in the United States from 1980 to 1990 and to analyze the proportional contribution of these changes. DATA SOURCES: Literature review, US statistics, health surveys, and ongoing clinical trials. STUDY SELECTION: Data representative of the US situation nationwide reported in adequate detail. DATA EXTRACTION: A computer-simulation state-transition model of the US population between the ages of 35 and 84 years was developed to forecast coronary mortality. The input variables were estimated such that the combination of values led to an adequate agreement with reported coronary mortality figures. Subsequently, secular trends were modeled. DATA SYNTHESIS: Actual coronary mortality in 1990 was 34% (127,000 deaths) lower than would be predicted if risk factor levels, case-fatality rates, and event rates in those with and without coronary disease remained the same as in 1980. When secular changes in these factors were included in the model, predicted coronary mortality in 1990 was within 3% (10,000 deaths) of the observed mortality and explained 92% of the decline; only 25% of the decline was explained by primary prevention, while 29% was explained by secondary reduction in risk factors in patients with coronary disease and 43% by other improvements in treatment in patients with coronary disease. CONCLUSIONS: These results suggest that primary and secondary risk factor reductions explain about 50% of the striking decline in coronary mortality in the United States between 1980 and 1990 but that more than 70% of the overall decline in mortality has occurred among patients with coronary disease.

Adult↗
PubMed1997

Cost-effectiveness of populationwide educational approaches to reduce serum cholesterol levels.

BACKGROUND: The aim of the present study was to estimate the cost-effectiveness of populationwide approaches to reduce serum cholesterol levels in the US adult population. METHODS AND RESULTS: This cost-effectiveness analysis was made from data from the literature and the Coronary Heart Disease Policy Model and was based on the US population age 35 to 84 years. Study interventions were populationwide programs to reduce serum cholesterol levels with costs and cholesterol-lowering effects similar to those reported from the Stanford Three-Community Study, the Stanford Five-City Project, and in North Karelia, Finland. The main outcome measures were cost-effectiveness ratios, defined as the change in projected cost divided by the change in projected life-years when the population receives the intervention compared with the population without the intervention. A populationwide program with the costs ($4.95 per person per year) and cholesterol-lowering effects (an average 2% reduction in serum cholesterol levels) of the Stanford Five-City Project would prolong life at an estimated cost of only $3200 per year of life saved. Under a wide variety of assumptions, a populationwide program would achieve health benefits at a cost equivalent to that of many currently accepted medical interventions. Such programs would also lengthen life and save resources under many scenarios, especially if the program affected persons with preexisting heart disease or altered other coronary risk factors. CONCLUSIONS: Populationwide programs should be part of any national health strategy to reduce coronary heart disease.

Adult↗
PubMed1997

Results of aortic bifurcation grafts for aortoiliac occlusive disease: a meta-analysis.

PURPOSE: To summarize mortality, morbidity, and long-term patency data of bifurcated aortoiliac or aortofemoral bypass graft procedures in aortoiliac occlusive disease. METHODS: A Medline search was performed of the medical literature published between 1970 and 1996. Studies were included if (1) they reported patency rates based on life tables and the number at risk was provided at yearly intervals; and (2) patient and study characteristics were reported in sufficient detail. Mortality and morbidity risks were pooled using a fixed-effects model. The patency data were combined using a technique that enables adjustment for differences across studies in patient characteristics or reporting methods. In the current analysis, we corrected for the symptomatic status of the patients at the time of surgery (claudication vs ischemia) and the unit of observation used in reporting the patency (limb vs patient). RESULTS: We identified 23 studies that met the inclusion criteria. The aggregated operative mortality risk in the older studies (started before 1975) was 4.6%, as compared with 3.3% in the more recent studies (p = 0.01). The aggregated systemic morbidity risk was 13.1% in the older studies and 8.3% in the more recent studies (p < 0.001). Limb-based patency rates for patients with claudication were 91.0% and 86.8% at 5 and 10 years, respectively, as compared with 87.5% and 81.8% for patients with ischemia. Patency rates reported in the older studies were markedly similar to those of more recent studies (p = 0.58). CONCLUSIONS: Our study suggests that mortality and systemic morbidity rates of aortic bifurcation graft procedures have dropped since 1975, whereas patency rates seem to be fairly constant over the years.

Aged↗
PubMed1997

Meta-analysis of the results of percutaneous transluminal angioplasty and stent placement for aortoiliac occlusive disease.

PURPOSE: To estimate and compare the results of percutaneous transluminal angioplasty (PTA) and stent placement to treat aortoiliac occlusive disease. MATERIALS AND METHODS: A meta-analysis was performed of data in six PTA studies (1,300 patients) and eight stent placement studies (816 patients) published in 1990 or later that met the inclusion criteria. Proportions were combined by means of a random-effects model. Failure-time data were pooled with and pooled without adjustment for differences in case mix. RESULTS: The immediate technical success rate in the PTA group was 91%; the rate was higher in the stent group (96%), but the difference was not statistically significant [corrected]. Complication and mortality rates were not statistically significantly different. Analyzed data included technical failures and were adjusted for lesion type and disease severity. Four-year primary patency rates were 65% for stenoses versus 54% for occlusions after PTA to treat claudication and were 53% for stenoses versus 44% for occlusions after PTA to treat critical ischemia. These rates were 77% for stenoses versus 61% for occlusions after stent placement to treat claudication and 67% for stenoses versus 53% for occlusions after stent placement to treat critical ischemia. The risk of long-term failure was reduced by 39% after stent placement compared with PTA. CONCLUSION: Stent placement and PTA yielded similar complication rates, but the technical success rate was higher after stent placement and the risk of long-term failure was reduced.

Angioplasty, Balloon↗
PubMed1996

Outcomes research and cost-effectiveness analysis in radiology.

The decision to implement a new medical technology requires that it not only increases survival or quality of life, but that it is also economically sound. The unique feature in the assessment of diagnostic tests is that the results of such tests are intermediate outcomes. Both randomized controlled clinical trials and decision analysis have an important role to play in the assessment of diagnostic tests. Important points to consider when performing a cost-effectiveness study are what perspective to take; comparing the technology with the next best strategy; including both effectiveness and costs; the distinction between describing and valuing the quality of life; intangibles such as the value of information; and the incremental cost-effectiveness ratio.

Cost-Benefit Analysis↗
PubMed1996

ROC analysis of noninvasive tests for peripheral arterial disease.

The purpose of this study is to evaluate the diagnostic accuracy of selected noninvasive tests for assessing peripheral arterial disease. The ankle/brachial index (ABI) and the femoral and popliteal pulsatility indices (PI), and combinations of these tests, were evaluated using receiver operating characteristic (ROC) analysis to determine their diagnostic accuracy depending on the localization of the disease. Verification bias, introduced by the preferential selection of patients for angiography based on the noninvasive test results, was examined. This study suggests that, in assessing whether a patient has significant peripheral arterial disease (lesions > or = 50%), determining an ABI is justified (ROC area 0.95 +/- 0.02). For disease localized to the aortoiliac segment, performing a single test, the femoral PI, is sufficient (ROC area 0.80 +/- 0.04). For disease including the femoropopliteal and infrapopliteal segments, a combination of tests is necessary. Utilized threshold values need to be adjusted for verification bias.

Adult↗
PubMed1996

Summary receiver operating characteristic curves as a technique for meta-analysis of the diagnostic performance of duplex ultrasonography in peripheral arterial disease.

RATIONALE AND OBJECTIVES: We summarized and compared the diagnostic performance of duplex and color-guided duplex ultrasonography in the evaluation of peripheral arterial disease. We present our research as an example of the use of summary receiver operating characteristic (ROC) curves in a meta-analysis of diagnostic test data. METHODS: A search of the English-language medical literature published between 1984 and 1994 retrieved 48 reports, 14 of which met the inclusion criteria. The analysis was limited to the aortoiliac and femoropopliteal segments because only two studies reported results of infrapopliteal arteries. Diagnostic performance of duplex and color-guided duplex, defined as the ability to detect a stenosis of 50-99% or an occlusion, was compared using summary ROC curve methodology. This method takes into account heterogeneity across studies attributable to differences in the threshold values used. RESULTS: The summary ROC curves demonstrated a high level of diagnostic performance for both types of duplex imaging, with color-guided duplex scanning being superior (p = .022). For example, at a false-positive rate of .05 (specificity = .95), the analysis predicted a true-positive rate (sensitivity) of .83 for duplex alone and .93 for color guided duplex. Differences in the case mix of the study population and study design did not affect the results. Furthermore, sensitivity analysis did not reveal a strong effect of any single study on the results. CONCLUSION: For aortoiliac and femoropopliteal arteries, the addition of color flow imaging to duplex scanning improves diagnostic performance in evaluating peripheral arterial disease.

Humans↗
PubMed1995

Revascularization for femoropopliteal disease. A decision and cost-effectiveness analysis.

OBJECTIVE: To evaluate the relative benefits and cost-effectiveness of revascularization for femoropopliteal disease using percutaneous transluminal angioplasty or bypass surgery. DESIGN: Decision analysis using a multistate transition simulation model (Markov process) and cost-effectiveness analysis from the perspective of the health care system. SETTING: Based on mortality, morbidity, patency, and cost data from a literature review. PATIENTS: Hypothetical cohort of patients with chronic femoropopliteal disease who desire revascularization. Subgroup analysis for patients defined by age, sex, indication, lesion type, and graft type. INTERVENTIONS: Percutaneous transluminal angioplasty, bypass surgery, and a strategies combining the two treatments. MAIN OUTCOME MEASURES: Five-year patency results, quality-adjusted life expectancy, lifetime costs, and incremental cost-effectiveness ratios. RESULTS: For 65-year-old men with disabling claudication and a femoropopliteal stenosis or occlusion and for 65-year-old men with chronic critical ischemia and a femoropopliteal stenosis, initial angioplasty increased quality-adjusted life expectancy by 2 to 13 months and resulted in decreased lifetime expenditures compared with bypass surgery. For patients with chronic critical ischemia and a femoropopliteal occlusion, initial bypass surgery increased quality-adjusted life expectancy by 1 to 4 months and resulted in decreased lifetime expenditures compared with angioplasty. Sensitivity analysis demonstrated that angioplasty would always be the preferred initial treatment if the angioplasty 5-year patency rate exceeds 30%. CONCLUSION: Angioplasty is the preferred initial treatment in patients with disabling claudication and a femoropopliteal stenosis or occlusion and in those with chronic critical ischemia and a stenosis. Bypass surgery is the preferred initial treatment in patients with chronic critical ischemia and a femoropopliteal occlusion.

Aged↗
PubMed1995

Triage of patients to angiography for detection of aortic rupture after blunt chest trauma: cost-effectiveness analysis of using CT.

OBJECTIVE: The purpose of this study was to evaluate the cost-effectiveness of dynamic chest CT, compared with plain chest radiography and immediate angiography, in deciding when angiography should be performed in hemodynamically stable patients with suspected aortic rupture after blunt chest trauma. The use of CT was evaluated in relation to the prior probability of aortic rupture. MATERIALS AND METHODS: A cost-effectiveness analysis comparing six diagnostic strategies combining chest radiography, CT, and angiography in various sequences was performed. Effectiveness was expressed as survival to hospital discharge, and costs were those incurred to society. Estimates for the variables in the analysis were derived from published reports. The model was evaluated for two cohorts of patients: those undergoing and those not undergoing CT for the evaluation of other injuries. Sensitivity analysis was performed for all variables in the model with emphasis on the prior probability of aortic rupture. RESULTS: Selecting patients for triage to angiography based on the CT findings yielded higher effectiveness at a lower cost-effectiveness ratio than doing so based on the chest radiograph, and the incremental cost-effectiveness ratio was less than $500,000 per life saved. For the cohort undergoing CT for the evaluation of other injuries, triage to angiography based on the CT findings yielded equivalent survival chances compared with immediate angiography and cost less ($1468 per patient evaluated compared with $2508). For the cohort not undergoing CT for other injuries, immediate angiography yielded the highest survival chances but was expensive, with an incremental cost-effectiveness ratio of $2 million per life saved compared with triage based on CT. In the latter cohort, immediate angiography yielded higher survival chances and had a cost-effectiveness ratio of less than $500,000 compared with the triage by CT if the prior probability of aortic rupture was 5% or more. CONCLUSION: Selecting hemodynamically stable patients after blunt chest trauma with suspected aortic rupture for angiography on the basis of CT findings is more effective than doing so based on the findings on chest radiography and is cost-effective compared with other accepted health care programs. Immediate angiography has a high incremental cost-effectiveness ratio compared with triage by CT and is warranted only in patients not undergoing CT for the evaluation of other injuries who have a prior probability of aortic rupture of 5% or more.

Angiography↗
PubMed1995

A survey of current problems in meta-analysis. Discussion from the Agency for Health Care Policy and Research inter-PORT Work Group on Literature Review/Meta-Analysis.

The United States Agency for Health Care Policy and Research brought together representatives from each of the Patient Outcomes Research Teams (PORTs) as the Inter-PORT Meta-Analysis Work Group. The purpose of the meeting was to discuss a wide range of problems the panel had encountered in the area of meta-analysis. Several actual problems were presented, and tentative solutions to those problems were given. The PORTs had to consider issues such as quality assessment, survival analysis, rare events, sensitivity and specificity, and random effects models. The solutions presented represent the methods used by several researchers who are active in the area of meta-analysis.

Evaluation Studies as Topic↗