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Biomedical subjects

M Bobbio

Publications and source records attributed to M Bobbio.

At least 55 records · Page 3Linked to original sources
PubMed1995

Incremental value of exercise electrocardiography and thallium-201 testing in men and women for the presence and extent of coronary artery disease.

Our goal was to assess the incremental value of exercise testing in men and women for the diagnosis and extent of coronary artery disease. With data from one center, incremental logistic algorithms were developed and evaluated in a separate set of 865 patients from four centers. Variables included were pretest (age, sex, symptoms, diabetes, smoking, and cholesterol concentration); exercise electrocardiogram (ECG) (ST-segment depression [millimeters], ST-segment slope, peak heart rate, and change in systolic blood pressure); and thallium-201 scintigram (defect presence, reversibility, and intensity of hypoperfusion). End points were coronary disease presence (50% diameter stenosis) and extent (multivessel disease). Accuracy and incremental value were assessed by receiver operating characteristic (ROC) curve analysis. Incremental ROC curve areas for disease presence were pretest 0.75 +/- 0.02, post-exercise ECG 0.82 +/- 0.01, and post-thallium scintigram 0.85 +/- 0.01 and for disease extent were pretest 0.71 +/- 0.02, post-exercise ECG 0.76 +/- 0.02, and post-thallium scintigram 0.78 +/- 0.02 (p < 0.005 for all increments). Incremental increases in accuracy were similar for men and women. We conclude that when multivariable algorithms derived from one center were applied to a separate group, there was a significant incremental increase in accuracy associated with exercise testing for the presence and extent of coronary disease. This increase in accuracy was similar for men and women.

Adult↗
PubMed1995

Effect of lipid-lowering treatment on progression of atherosclerotic lesions--a duplex ultrasonographic investigation.

The Prevenzione Aterosclerosi Studio Torino (P.A.S.T.) was a prospective, randomized trial testing the effect on carotid and femoral atherosclerotic lesions of lipid-lowering therapy, as assessed by duplex scanning (DS) technique, in 85 patients (12 women, 73 men), forty-five to fifty-five years old, with ischemic heart disease (IHD), and randomly assigned to a hypolipidemic diet or diet + 250 mg acipimox (a nicotinic acid compound) two to three times/day. Forty-one patients, without inclusion criteria, were compared with the randomized groups as a reference population. All three groups were submitted to DS and to hematic monitoring of lipid levels at the beginning and at the end of the study. During three years of treatment, there was a significant reduction (-6.5%) in total plasma cholesterol in the diet + drug group (P = 0.04) and a simultaneous elevation of high-density lipoprotein cholesterol, significant in the treatment groups (respectively, +15% P = 0.02 in the diet and +16% P = 0.016 in the diet + drug group). Every group showed a trend toward the increasing number of lesions in all explored areas and toward the progression in size of the already existing ones. Whereas in the initial DS the prevalence of lesions was significantly lower in the nonrandomized group in every site, at the end of the study the total number of lesions did not differ among groups, and there was a significant increase of plaques in carotid area in the nonrandomized group in comparison with the treatment groups. The final number of stable plaques was greater in the treatment groups as compared with the nonrandomized group (P = 0.01 diet vs nonrandomized, P = 0.03 diet + drug vs nonrandomized). In conclusion, lipid-lowering treatment, with diet and with diet + drug, was useful in slowing the natural progression of atherosclerosis; particularly, it reduced the development of new lesions in the carotid and femoral arteries and increased the stability of the already existing ones. In these patients, diet was equivalent to diet + drug in regard to progression of lesions. The most favorable results in the treatment groups seem to correlate with high-density lipoprotein cholesterol, significantly increased in comparison with the nonrandomized group.

Arteriosclerosis↗
PubMed1994

Completeness of reporting trial results: effect on physicians' willingness to prescribe.

Clinical trials may lead to conflicting results. We studied how different ways of reporting results affected physicians' recommendations. A questionnaire distributed to 148 general practitioners presented results of a clinical trial where a reduction of cardiac events and an increase of mortality was reported. Results were shown in four different ways--relative risk reduction, absolute risk reduction, percentages of event-free patients, number needing to be treated to prevent an event--as if they derived from different trials. A fifth presentation was the reduced rate of cardiac events along with the increased rate of mortality. Physicians were asked to estimate how much they would be willing to prescribe each drug. The mean agreement of physicians' decisions was 77 (28)% for relative risk reduction, 24 (28)% for absolute risk reduction, 37 (37)% for different percentages event-free patients, 34 (34)% for number need to treat, and 23 (28)% for events reduction and mortality for increase (p < 0.001 relative risk vs others). The method of reporting trial results and the completeness of information in the case of controversial results affects physicians willingness to prescribe.

Clinical Trials as Topic↗
PubMed1994

Incremental evaluation of exercise capacity as an independent predictor of coronary artery disease presence and extent.

To determine the independent incremental value of exercise capacity (METS) concerning the presence and extent of coronary artery disease, we analyzed data from 800 patients with suspected coronary disease who underwent both exercise testing and coronary angiography. We performed logistic regression analysis of clinical and exercise test data with an incremental design to mimic the usual flow of data acquisition. Separate analyses were performed concerning coronary disease presence (> or = 1 vessel with a > or = 50% lesion) and extent (three-vessel/left main disease). Diagnostic accuracy was determined by calculating receiver operating characteristic (ROC) curve areas. When considered alone, METS was a significant predictor of both presence and extent of disease. Multivariate analysis revealed that METS was an independent predictor of disease extent but not presence. However, comparison of ROC curve areas failed to show any loss of accuracy when METS was removed from the coronary disease extent analysis. Despite the strong univariate relationship between exercise capacity and coronary disease presence and extent and the independence of exercise capacity as a predictor of coronary disease extent, the lack of an additional incremental accuracy attributed to its consideration virtually cancels its value as a diagnostic variable for assessing both coronary disease presence and extent.

Adult↗
PubMed1994

Diagnostic accuracy of predicting coronary artery disease related to patients' characteristics.

Patients' demographic and clinical characteristics may affect diagnostic accuracy of cardiologists. We asked a group of experienced cardiologists from three institutions to estimate the pretest probability of coronary artery disease in 257 patients referred for diagnostic coronary angiography and with no history of previous myocardial infarction nor valvular heart disease. Physicians pretest estimates were compared with the diagnostic findings of coronary angiography. We tested the influence of five variables on the accuracy of the pretest estimates: age, sex, chest pain characteristics, rest electrocardiogram and electrocardiographic exercise test result. Cardiologists tended to overestimate the presence of coronary artery disease and this tendency was particularly remarkable in the group of patients showing a negative exercise test. Pretest diagnostic accuracy was 0.72 when the test result was negative and 0.85 when the test result was positive (95% confidence interval of the difference 0.03 to 0.23; p < 0.001). The diagnosis of coronary artery disease was also more accurate for male than for female patients (0.81 vs 0.70; 95% confidence interval of the difference 0.02 to 0.21; p < 0.02). Characteristics of chest pain, age and rest electrocardiogram did not affect the level of pretest diagnostic accuracy. Cardiologists should be cognizant of correctly interpreting a negative exercise test and the clinical data of female patients; in both cases, they should move circumspect of the diagnosis of coronary artery disease.

Age Factors↗
PubMed1994

[Does coexistence of involvement of the right dominant coronary artery differentiate clinical features of disease of the common trunk from disease of 3 coronary vessels?].

We have studied clinical and ECG stress features of 119 patients with left main disease and 113 matched patients with three vessels coronary disease. Clinical features and ECG stress test do not differentiate the two groups as a whole. Exercise time duration was shorter, ST criteria were more positive, and peak heart rate was lower in the subgroups of patients with left main and involvement of a right dominant coronary artery. However due to a large overlap these criteria do not seem to be clinically useful. In conclusion, in an individual patient angina and stress ECG criteria do not differentiate the patients with left main from those with three vessels coronary artery disease.

Angina Pectoris↗
PubMed1994

[Do our patients follow the clinical indications prescribed after coronary angiography?].

BACKGROUND: Aim of the study is to evaluate patients compliance with therapeutic recommendations after coronary angiography. METHODS: We analyzed all patients who underwent coronary angiography in an university center during 1990. One of the following treatments were recommended: medical therapy without revascularization, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting. A cohort of 392 patients was assessed one year after coronary angiography in order to evaluate clinical predictors of non compliance with the treatment recommended. RESULTS: Of the 141 patients, for whom medical treatment was recommended, 16 (11%: 95% confidence interval 6-17%) had revascularization. By stepwise discriminant regression analysis, older age, congestive heart failure and critical lesion of the left anterior descending artery were statistically significant predictors of non compliance. Of the 137 patients, for whom PTCA was recommended, 8 (6%: 2-9%) were non compliant. No variables were predictive of non compliance. Of the 114 patients, for whom CABG was recommended, 15 (13%: 7-19%) were non compliant. By stepwise regression analysis, absence of typical angina was predictive of non compliance. For 12 patients non compliance was related to personal preferences, for 10 to clinical deterioration, for 9 to a second opinion, and 3 were still in the surgical waiting list one year after coronary angiography. One year mortality was not affected by non compliance. CONCLUSIONS: Non compliance to recommended treatment after coronary angiography is uncommon and is mainly related to patients preference towards a less invasive treatment or to a change of clinical conditions over time.

Aged↗
PubMed1993

How the exercise electrocardiogram is used in clinical practice in patients with suspected coronary artery disease.

Clinical use of a test should be evaluated not only on the change of pretest probability but also on the increased confidence in the judged probability, and on the decision of recommending additional tests or therapy after test results. Before and after the test, cardiologists referring a patient for exercise electrocardiogram for suspected coronary artery disease were asked to estimate the probability of coronary artery disease and the minimal and maximal value of their estimate (plausible range), to judge whether to refer the patient for coronary angiography, and to specify patient's treatment. After the test, the percentage of patients with estimated probability < or = 20% increased (from 53 to 69%; p = 0.005) and the percentage of patients with intermediate probability (between 21 and 80%) decreased (from 37 to 16%; p = 0.0001). The mean plausible range decreased from pre- to post-test assessment (31 +/- 23 to 15 +/- 16%; p = 0.0001), indicating an increase in cardiologists' confidence in their estimates. After the test, the percentage of cardiologists who wished to either refer or not refer patients for coronary angiography increased (from 4 to 13%, p < 0.005; and from 37 to 65%, p < 0.0001, respectively). Test results enable cardiologists to change the assessment of disease probability, the confidence in their own estimates, and their judgment of whether to refer patients for coronary angiography.

Adult↗