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Biomedical subjects

M Di Bari

Publications and source records attributed to M Di Bari.

At least 19 recordsLinked to original sources
PubMed1998

Effective arterial elastance and the hemodynamic effects of intraaortic balloon counterpulsation in patients with coronary heart disease.

OBJECTIVES: The goal of the present study was to analyze the effects of different intraaortic balloon counterpulsation (IABC) inflation volumes on effective arterial elastance (Ea) in patients with complicated coronary heart disease and to determine whether Ea can predict the hemodynamic response to IABC. BACKGROUND: Ea (the central aortic end-systolic pressure to stroke volume ratio) incorporates the principal elements of input arterial impedance and has been proved useful to evaluate the effects of afterload reduction in patients with left ventricular (LV) failure. However, although the hemodynamic action of IABC can be considered as a typical example of "pure" afterload reduction, it has never been assessed in terms of changes in Ea. METHODS: After clinical stabilization, 18 patients treated with IABC for complicated acute myocardial infarction or unstable angina were enrolled in the study. Systemic hemodynamics were measured by use of right cardiac thermodilution catheters with IABC off (control) and IABC on at balloon inflation volumes of 20 and 40 ml, in randomized sequence. Aortic pressure was recorded through the central lumen of the IABC catheter to calculate Ea as the ratio of aortic dicrotic pressure to stroke volume. RESULTS: A higher control Ea was associated with a lower control LV stroke work and a larger IABC-related hemodynamic improvement (that was maximal with the 40 ml inflation volume). The increase in LV stroke work was closely related to the decrease in Ea. Accordingly, hemodynamic benefits from IABC were less evident in patients with lower control Ea. In conclusion, effects of IABC were related to both balloon inflation volume and control hemodynamics, reflecting the afterload dependence of a depressed LV function.

Aged↗
PubMed1997

Transthoracic three-dimensional echocardiographic reconstruction of left and right ventricles: in vitro validation and comparison with magnetic resonance imaging.

Two-dimensional (2D) echocardiographic and angiographic measurements of ventricular volumes are limited by geometric assumptions concerning cavity shape. We compared in vitro the accuracy of a three-dimensional (3D) echocardiographic system suitable for transthoracic imaging to magnetic resonance imaging (MRI) in the measurement of left and right ventricular volumes. Ventricular cast volumes from 14 excised formalin-fixed sheep hearts filled with an agarose solution were compared with data derived from 3D echocardiography and MRI. Left and right ventricular volumes from 3D echocardiographic reconstructions agreed well with actual volumes without significant underestimation or overestimation. MRI progressively underestimated left ventricular volumes as these increased and systematically underestimated right ventricular volumes. Our echocardiographic system designed for 3D transthoracic imaging combines excellent measurements of left and right ventricular volumes and the computed reconstruction of tomographic slices with the full spatial resolution of the original 2D images. Thus in this in vitro model, 3D echocardiography exhibited greater accuracy than MRI.

Animals↗
PubMed1995

Immediate and long-term survival after intra-aortic balloon pumping: is advanced age an independent, unfavorable prognostic factor?

OBJECTIVE: To determine whether advanced age is an independent prognostic factor that may increase the risk of complications and reduce the immediate and long-term survival after treatment with intra-aortic balloon pumping (IABP) for acute ischemic heart disease. DESIGN: Retrospective analysis of a clinical series and long-term follow-up study. PATIENTS: A total of 142 patients (age range 23-86 years) in whom IABP was indicated following a standardized protocol. MEASUREMENTS: Univariate analysis of the association between age and anamnestic, clinical, and hemodynamic data significantly affecting prognosis; multivariate logistic regression analysis of variables showing significant associations. RESULTS: IABP-related complications were independent of age. At univariate analysis, pre-existing, noncardiac, associated conditions (chronic renal failure, stroke, bronchopulmonary disease) (P < .001), an indication to IABP for hemodynamic complications of acute myocardial infarction rather than for medically refractory myocardial ischemia (P < .001), a lack in hemodynamic response to IABP (P < .002), a prolonged delay to IABP initiation (P < .003), and advanced age (P < .025) were all predictors of in-hospital mortality. However, older patients were also more frequently affected by chronic comorbid conditions and by acute left ventricular failure as an indication to IABP. When these variables were entered into logistic regression models, the association between age and mortality was no longer statistically significant. Similarly, advancing age was associated (P < .012) with an increased mortality rate during an average follow-up of 94 +/- 9 months, but, again, such a significant association disappeared when simultaneously adjusting for New York Heart Association functional class, which was the single most important predictor of long-term mortality. CONCLUSIONS: Several anamnestic and clinical variables, rather than advanced age itself, are independent, prognostic factors negatively affecting the outcome of treatment with IABP. Technique-related complications are independent of age. Thus, old age should not be considered as a criterion to exclude any patient, a priori, from the potential benefits of this type of cardiocirculatory assistance.

Acute Disease↗
PubMed1995

[Evaluation of the efficacy of oral sumatriptan in the management of migraine attacks. Clinical results].

This italian multicentre, double blind, parallel groups study compared the efficacy, safety and tolerability of oral sumatriptan, given as new film-coated tablet, with placebo in the acute treatment of migraine. 88 Patients received placebo and 162 patients received sumatriptan 100 mg (plus an optional dose 2 h later if the headache persisted plus a further optional dose for recurrence within 24 h). Sumatriptan was significantly more effective than placebo at releiving headache at 2 h (51% versus 31%, P = 0.003) and 4 h (71% versus 35%, P < 0.001). Fewer sumatriptan-treated patients required a second dose compared with placebo-treated patients (49% versus 74%, P < 0.001). Sumatriptan was more effective than placebo at relieving nausea, vomiting and photophobia/phonophobia. Few patients were evaluable for treatment of headache recurrence, and statistical analysis was not possible. More sumatriptan-treated patients than placebo-treated patients reported adverse events (29% versus 16%) but the difference was not statistically significant. More of these events were mild to moderate in severity, of short duration and resolved without treatment. Sumatriptan had no clinically significant effect on blood pressure, heart rate, electrocardiogram or laboratory test results. It is concluded that oral sumatriptan 100 mg, given as a film-coated, tablet, provides an effective and well-tolerated acute treatment for migraine.

Acute Disease↗
PubMed1993

Acute and long-term effects of flosequinan in patients with chronic cardiac failure.

The acute and long-term effects of the orally active vasodilator flosequinan were assessed in 10 patients with New York Heart Association class II to IV cardiac failure. Baseline hemodynamics, exercise capacity, left and right ventricular ejection fraction, and pulmonary transit time were measured by right cardiac catheterization, bicycle ergometer stress testing, and nuclear angiocardiography during a run-in period on placebo. Acute hemodynamic effects of flosequinan were monitored for 48 hours; the drug was then given as a single 100 mg daily dose for 6 weeks. Exercise capacity was reevaluated every 2 weeks, and right cardiac catheterization and nuclear angiocardiography were repeated at the end of the 6-week period. Placebo did not exert any effect. Flosequinan reduced right atrial, pulmonary artery, and pulmonary artery wedge pressures from 60 minutes to 48 hours after dosing. Heart rate was minimally increased. Cardiac index, mean systemic arterial pressure, and systemic and pulmonary vascular resistance were substantially unaffected. These effects were maintained after 6 weeks. Exercise capacity was enhanced after 2, 4, and 6 weeks. Left ventricular ejection fraction was unchanged, whereas right ventricular ejection fraction and pulmonary transit time were improved. In conclusion, flosequinan exerted a potent, long-lasting, venodilating effect that was maintained long-term, without evidence of tolerance.

Aged↗
PubMed1992

[Brain aging and calcium antagonist drugs. A preliminary open study with nimodipine].

Forty patients aged 65-80 with minor-medium signs of brain aging were treated for 6 months with daily 90 mg doses of nimodipine. Treatment was well tolerated in that the minor side effects reported by a few of the patients never required withdrawal of the drug. Treatment proved useful, as shown by a variety of mental tests, in 69.5% of cases. In 20% conditions remained unchanged and in 9.5% further deterioration was observed. The authors conclude that nimodipine may be considered a useful therapeutic resource for phenomena of brain aging.

Aged↗
PubMed1991

[Raynaud's phenomenon and calcium blocking agents. A preliminary open study with flunarizine].

Raynaud's phenomenon (Raynaud's disease), an accessual vascular acrosyndrome characterised by an important constriction of distal arterioles, has still no specific pharmacological therapy. In the last years, the use of calcium-entry-blockers (nifedipine, diltiazem, verapamil, nicardipine), drugs able to control the contractility of the vessels, showed some positive results. Considering this data, we appraised the efficacy of flunarizine, another calcium-entry-blocker, in a preliminary study of 28 patients (23 females, 5 males, aged between 15 and 48 years) suffering from Raynaud's disease. Apart from a statistically insignificant improvement of subjective symptoms (i.e. acroparesthesias, cold extremities) flunarizine (10 mg/day for 1 month) did not have positive results. Finally, this drug caused some side-effects: drowsiness, increase of weight and appetite, but without a real necessity for withdrawal of therapy.

Adolescent↗
PubMed1990

Age-related changes in the pharmacodynamics of intravenous glyceryl trinitrate.

Comparable hemodynamic effects were obtained administering a much lower intravenous dose of glyceryl trinitrate (GTN) in elderly than in younger patients. The pharmacodynamics and kinetics of GTN were thus assessed in 2 groups of patients with acute myocardial infarction (group A: less than or equal to 65 years, 6 patients; group B: greater than or equal to 75 years, 6 patients). The arterial and venous dose-concentration relationship and the associated hemodynamic changes at end-point (EP: 10% reduction in mean systemic arterial pressure) were similar in the 2 groups. However, in older subjects EP was reached at a lower GTN infusion rate (0.11 +/- 0.04 vs 0.33 +/- 0.11 micrograms.kg-1.min-1, mean +/- S.D.; p less than 0.001), and with lower arterial and venous drug concentrations (arterial [GTN]: 1.2 +/- 0.1 vs 4.6 +/- 1.2 ng.ml-1; p less than 0.01; venous [GTN]; 0.09 +/- 0.05 vs 0.35 +/- 0.15 ng.ml-1; p less than 0.05), whereas overall GTN kinetics appeared to be substantially independent of age. Thus, the enhanced efficacy of GTN in advanced age seems to stem mainly from pharmacodynamic changes, which may be the consequence of dampened baroreceptor reflexes, as suggested by a lower heart rate increase per unitary fall in systolic arterial pressure observed in group B (0.12 +/- 0.07 vs 0.41 +/- 0.29 b.min-1.mmHg-1; p less than 0.05).

Aged↗
PubMed1988

Age-related hemodynamic effects of intravenous nitroglycerin for acute myocardial infarction and left ventricular failure.

Acute hemodynamic effects of intravenous nitroglycerin (NTG) were assessed in 24 patients with acute myocardial infarction and left ventricular failure, and results were compared between 2 groups of different age (group A--65 years or less, n = 12; group B--75 years or more, n = 12). Overall, hemodynamic effects of NTG consisted of an increase in stroke volume index and left ventricular stroke work index (+21 and +23%), coupled with a 16% reduction in systemic vascular resistance, and of a marked decrease in right atrial and pulmonary artery (PA) pressures. The hemodynamic end-point (5 to 10% reduction in mean systemic arterial pressure) used for NTG titration was achieved with a significantly lower dose in group B, in which a greater percent reduction in mean PA and mean PA wedge pressures was also observed. However, because effects of NTG on systemic vascular resistance were similar in groups A and B, it was concluded that the vasodilating action of NTG is maintained in advanced age, as opposed to what has been demonstrated for beta-adrenergic agents.

Aged↗
PubMed1988

Improved exercise tolerance by i.v. fructose-1,6-diphosphate in chronic, stable angina pectoris.

The effect of IV fructose-1,6-diphosphate (FDP) on transient, reproducible myocardial ischemia was evaluated in ten patients, aged 50 to 66 years, with chronic, stable exertional angina. FDP or placebo (glucose) were administered between basal and posttreatment ergometric stress testing; an identical procedure was repeated in each patient with the second treatment on the following day according to a single-blind, cross-over design. FDP improved exercise tolerance and total work capacity, significantly delaying the onset of ST-segment depression and angina. Nevertheless, the critical level of the rate x pressure (R X P) product, causing appearance of myocardial ischemia, was not remarkably changed. However, the R X P product at same workload was significantly lower after FDP. These results suggest that improved exercise tolerance might have resulted from peripheral (increased oxygen delivery to skeletal muscle) rather than from central (cardiac) effects of FDP.

Aged↗
PubMed1987

Two-dimensional echocardiographic imaging: in vitro comparison of conventional and dynamically focused annular array transducers.

Quantitative two-dimensional echocardiography has been adversely affected by a tendency for underestimation of cross-sectional areas of cardiac chambers, a difficulty that might be ameliorated by recent advances in imaging technology. To determine if this were so, we measured echocardiographic cross-sectional areas of 25 formalin-fixed animal left ventricular (LV) sections in vitro using conventional 13 mm and 15 mm diameter fixed-focused single element transducers, and a 15 mm diameter dynamically focused annular array transducer at 3 different distances between myocardial slice and transducer (2 cm, 6 cm and 10 cm) and compared the 2-dimensional echocardiographic areas to the corresponding anatomic cross-sectional areas of the same hearts. LV total and cavity area were measured by computer assisted planimetry of videotaped echo images, performed blinded to the transducer used, and photographed anatomic slices; LV myocardial area was derived by subtraction. Comparison of two-dimensional echocardiographic total, myocardial, and cavity areas with corresponding anatomic measurements showed excellent correlation for each transducer at all depths (r = 0.97 to 0.98 for total area; r = 0.98 to 0.99 for cavity area; r = 0.93 to 0.97 for myocardial area). For total and myocardial cross-sectional areas, the slope of the relation between echographic and anatomic areas did not differ significantly from unity, but for LV cavity area this was achieved only by the dynamically focused transducer. In contrast, the conventional 13 mm transducer significantly underestimated larger LV cavity areas in both the near and middle fields (slopes = 0.90 and 0.91, respectively) and the 15 mm transducer yielded slopes from 0.86 to 0.91 in all fields.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiography↗
PubMed1986

Prediction of left ventricular function in acute anterior myocardial infarction by serum creatine kinase activity and precordial ECG mapping.

Right cardiac catheterization, serial determination of creatine phosphokinase (CPK) and of CPK-MB activities, and precordial 35-lead ECG mapping were performed in 17 consecutive patients with a first anterior acute myocardial infarction (AMI) within 6 hours of the onset of symptoms. Left ventricular function as determined by the stroke index (SI, ml/m2) to mean pulmonary capillary wedge pressure (PCWP, mmHg) ratio inversely correlated either with the total CPK and CPK-MB released and with peak enzymatic activity, or with the entity of early (6th hour ECG) ST-segment elevation. Conversely, a direct correlation was found between the SI/PCWP ratio and the ratio of R to Q+S waves from late (48th hour) ECG. Residual left ventricular function after a first anterior AMI can therefore be estimated noninvasively in the individual patient by early precordial ECG mapping and by peak enzymatic activity.

Adult↗
PubMed1985

Hemodynamic and electrocardiographic effects of fructose-1,6-diphosphate in acute myocardial infarction.

Acute hemodynamic and electrocardiographic effects of fructose-1,6-diphosphate (FDP), an agent that is supposed to restore anaerobic glycolytic flux in the ischemic myocardium, were studied in 40 patients with acute myocardial infarction who were grouped into 4 subsets: subset 1, normal (15 mm Hg or less) pulmonary artery (PA) wedge pressure and normal (35 g-m/m2 or greater) left ventricular (LV) stroke work index; subset 2, elevated (more than 15 mm Hg) PA wedge pressure and normal LV stroke work index; subset 3, normal PA wedge pressure and reduced (less than 35 g-m/m2) LV stroke work index; subset 4, elevated PA wedge pressure and LV stroke work index moderately reduced to a range between 16 and 34 g-m/m2. Patients were randomized into an FDP (250 mg/kg body weight in isotonic saline solution intravenously in 20 minutes) and into a placebo group. Each subset contained 5 FDP- and 5 placebo-treated patients. After basal measurements, hemodynamic measurements were reassessed at 60, 90 and 120 minutes from the infusions, while a standard 12-lead electrocardiogram was recorded in the basal state and 120 minutes after infusion. Nonsignificant hemodynamic change was observed in the placebo subsets, and FDP failed to exert any effect in subsets 1, 2 and 3. A 24% (p less than 0.02) increase in cardiac index occurred 60 minutes after FDP in subset 4. LV stroke work index also increased, while PA wedge pressure remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Hemodynamic effects of digoxin in acute myocardial infarction in man: a randomized controlled trial.

Hemodynamic effects of digoxin in acute myocardial infarction (AMI) have been acknowledged to depend on the basal cardiocirculatory state. In the present study, the effects of digoxin in patients with AMI were evaluated in four hemodynamic subsets, based on the relationship between mean pulmonary capillary wedge pressure (PCWP, in mm Hg) and left ventricular stroke work index (LVSWI, in g-m/m2): subset 1: normal (less than or equal to 15 mm Hg) PCWP and normal (greater than or equal to 35 g-m/m2) LVSWI; subset 2: elevated (greater than 15 mm Hg) PCWP and normal LVSWI; subset 3: reduced (less than 35 g-m/m2) LVSWI and normal PCWP; and subset 4: elevated PCWP and LVSWI moderately reduced to a range between 16 and 34 g-m/m2. Forty patients were admitted to the study and were randomly assigned to one of two groups in each subset: control group (19 patients) and treated group (21 patients). Five patients were randomized into each of the subsets 2, 3, and 4 in both the control and treated groups, while in subset 1 there were four control and six digoxin-treated patients. Control patients were administered a placebo saline solution and digoxin-treated patients received 0.50 mg of the drug intravenously in 20 minutes. The effects of the placebo and of the drug were evaluated at 30, 60, and 90 minutes from the end of the infusion. Hemodynamic data did not vary in the control group, and digoxin did not exert any relevant effect in subsets 1 and 2. After drug infusion, cardiac index (Cl, in L/min/m2) significantly increased in subset 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗