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G B Mancini

Publications and source records attributed to G B Mancini.

At least 73 records · Page 4Linked to original sources
PubMed1992

Left ventricular shape changes during the course of evolving heart failure.

The temporal relationship between left ventricular (LV) shape changes and the development of LV dysfunction, dilation, and sympathoadrenergic hyperactivity was examined in 10 dogs with chronic heart failure produced by multiple sequential intracoronary microembolizations. LV shape was quantitated from serial ventriculograms based on the ratio of the major to minor axis at end systole and end diastole. Measurements were made at baseline (before embolizations) and were repeated at 2, 8, and 16 wk after the last embolization. A significant increase of LV sphericity was present at 2 wk, with only minimal changes occurring thereafter. Despite the tendency for LV shape changes to plateau between 2 and 16 wk, LV ejection fraction continued to decline (31 +/- 1 vs. 20 +/- 2%; P less than 0.001), and LV end-diastolic volume continued to increase (86 +/- 6 vs. 103 +/- 9 ml; P less than 0.01) as did plasma norepinephrine concentration (456 +/- 30 vs. 868 +/- 172 pg/ml; P less than 0.02). These data indicate that in the course of evolving heart failure, LV shape abnormalities precede the development of profound LV dysfunction, dilation, and overt activation of the sympathetic nervous system.

Adrenal Glands↗
PubMed1992

Asymptomatic coronary artery disease in patients with stroke. Prevalence, prognosis, diagnosis, and treatment.

The frequency of angiographically defined asymptomatic CAD in patients with carotid disease is 40%. Although the prognosis of patients with asymptomatic 1-vessel or 2-vessel CAD is good (annual cardiac mortality rate less than 2%), the prognosis of asymptomatic 3-vessel disease or left main CAD is substantially less favorable (annual cardiac mortality 5-8%). Preliminary data from nonrandomized studies suggest that coronary artery bypass surgery significantly lowers cardiac mortality in patients with asymptomatic 3-vessel or left main CAD. Further studies are needed to determine 1) vascular risk factor profiles that are predictive of asymptomatic CAD in patients with cerebrovascular disease and 2) the prevalence of asymptomatic CAD, especially 3-vessel and left main CAD, in patients with a variety of subtypes of cerebrovascular disease (e.g., carotid disease, atherosclerotic vertebrobasilar disease, cardioembolism, penetrating artery disease, stroke of undetermined cause). If the prevalence of asymptomatic 3-vessel or left main CAD is high in a subset of patients with cerebrovascular disease, a randomized study comparing coronary artery bypass surgery with best medical therapy (anti-ischemic agents, lipid-lowering therapy, and aspirin) may be warranted.

Cerebrovascular Disorders↗
PubMed1991

Accuracy and reproducibility of quantitative coronary arteriography using 6 and 8 French catheters with cine angiographic acquisition.

To determine the suitability of 6 French catheters for quantitative coronary arteriography, the relative accuracy and reproducibility of one type of these catheters was compared to that obtained with standard 8 French catheters in 20 stenoses. Duplicate injections with polyurethane 6 French catheters were obtained using hand and power injection technique with cineangiographic acquisition (four 6 French catheter injections total per stenosis). Measurements of both percent diameter stenosis and absolute dimensions were compared to those obtained with hand injection and cine acquisition using 8 French catheters as a "gold standard." While the reproducibility of dimension determination with the 6 French catheter was generally similar to that obtained with the 8 French catheter (0.27 +/- 0.23 mm for absolute diameter and 8.1 +/- 7.4% for percent diameter stenosis), accuracy was significantly less for the 6 French catheter for measurement of absolute dimensions. Thus, while apparently well suited for serial measurements of the same stenoses, 6 French catheters may not be as accurate in the determination of absolute artery dimensions as 8 French catheters.

Angiography↗
PubMed1991

Quantitative regional curvature analysis: validation in animals of a method for assessing regional ventricular remodelling in ischemic heart disease.

Recent studies show the impact of left ventricular shape and remodelling on patient prognosis. This mandates the development of quantitative methods for measuring shape. Quantitative regional curvature analysis (QRCA) was developed to quantitate shape on a regional basis so that measurements would not be constrained to assessment of only global shape and would, therefore be applicable to ischemic heart disease. To validate QRCA, eleven dogs were instrumented with coronary occluders and radiopaque markers on the epicardium and endocardium to provide fiducial points for calculation of shape, motion and thickening. These parameters were measured in the anterior and inferior walls, at rest, during left anterior descending occlusion and finally during circumflex occlusion. QRCA showed increased curvature (increased globularity) in each wall when thickening and motion deteriorated during occlusion. The most marked shape changes occurred in the inferior wall whereas the most marked deterioration of function was detected by wall thickening measurements of the anterior wall. Thus, QRCA detects regional ventricular shape disorders coincident with regional dysfunction induced by ischemia. These changes show regional heterogeneity and demonstrate the potential importance of this measurement as opposed to simple, global measures of shape. QRCA is, therefore, suitable for monitoring acute changes of shape that occur during acute ischemia.

Algorithms↗
PubMed1991

Results of primary repair of digital nerves.

Recovery of sensitivity following repair of 54 digital nerves was evaluated after one to seven years. Normal two-point discrimination has been regained in only seven cases (13%), two-point discrimination between 6 and 10 mm in 20 (37%), between 11 and 15 mm in 13 (24%) and protective sensation in 14 (26%). A close correlation between age and recovery of sensation after repair has been confirmed by statistical analysis. Microsurgical repair of digital nerves gives satisfactory results, since a normal or good two-point discrimination can be obtained in one-half of cases while sensation improves in the others. However a high rate of complete recovery of sensation is to be expected only in children.

Adolescent↗
PubMed1991

Quantitative coronary arteriographic methods in the interventional catheterization laboratory: an update and perspective.

Recent research advances in the area of quantitative coronary arteriography are described with respect to their potential role in assessing the effects of interventional therapy and monitoring the restenosis process. Specific areas emphasized are the importance of quantitative arteriography and absolute measures of arterial dimension in monitoring restenosis, the development of a computerized method for measuring lesion roughness, the potential role of measuring stenosis flow reserve based on component analysis principles, limitations of direct measures of myocardial flow reserve using a digital angiographic method and cautionary notes about clinical applications of videodensitometry. The current use of radiography and quantitative measures in limiting arterial injury are briefly reviewed. Finally, a perspective is put forth on the need to develop complementary roles for endovascular echocardiography and angioscopy with existing radiographic imaging technology.

Angiography, Digital Subtraction↗
PubMed1991

Relation between maximum time-varying elastance pressure-volume areas and myocardial oxygen consumption in dogs.

To establish whether pressure-volume areas (PVAs) calculated using the maximum time-varying elastance (Emax) have a relation with myocardial oxygen consumption (MVO2) that improves on other indexes of myocardial oxygen demand, we studied nine dogs of either sex weighing 19-39 kg, which were instrumented with a micromanometer left ventricular (LV) catheter and a Wilton-Webster coronary sinus flow catheter and had red blood cells tagged with technetium-99m for radionuclide angiography. Hemodynamics, coronary sinus flow determinations, and radionuclide angiograms were obtained under control conditions and during three to five steady-state loading conditions (mean +/- SD, 5.6 +/- 0.7). Isochronal pressure-volume data points from each pressure-volume loop were subjected to linear regression analysis to calculate Emax. The Emax relations, diastolic curves, and systolic portions of each pressure-volume loop were used to obtain calibrated PVAs. The Emax PVA (mm Hg.ml.beat-1.100 g-1) and MVO2 (ml O2.beat-1.100 g-1) values correlated in each animal (r = 0.77 to 0.99). Their slopes averaged (3.48 +/- 1.68) x 10(-5) ml O2.mm Hg-1.ml-1, and their y-axis intercepts averaged 0.07 +/- 0.04 ml O2.beat-1.100 g-1. When the MVO2 relations were compared with Emax PVA, LV systolic pressure-rate product, LV stroke work, and a modification of the LV pressure-work index, the Emax PVA, LV systolic pressure-rate product, and LV pressure-work index had similar relations with MVO2, whereas LV stroke work was a weaker index of MVO2 (p less than 0.05 versus Emax PVA). This occurred because the Emax PVA:MVO2 slopes and y-axis intercepts differed in each dog, which was due to differences in basal LV contractility. The Emax PVA:MVO2 slopes correlated with Emax (r = 0.73, p less than 0.05), and the y-axis intercepts were also weakly related to Emax (r = 0.48, p = 0.19). We conclude that the Emax PVAs calculated using data acquisition techniques that are clinically applicable have relations with MVO2 that in general do not improve on other indexes of myocardial oxygen demand in this animal preparation.

Animals↗
PubMed1991

Instantaneous hyperemic flow-versus-pressure slope index. Microsphere validation of an alternative to measures of coronary reserve.

BACKGROUND: The instantaneous hyperemic flow-versus-pressure (i-HFVP) slope index is a new method of assessing maximal coronary conductance and can be used as an alternative to conventional measures of coronary reserve. The i-HFVP slope index is determined by measuring the slope of the linear diastolic segment of the relation between instantaneous aortic pressure and hyperemic coronary flow. METHODS AND RESULTS: To validate the i-HFVP slope index as a measure of maximal coronary conductance, we compared this method with a microsphere-derived measurement of maximal coronary conductance (m-HFVP slope index) by determining the slope of the least-squares regression line of the data points for coronary flow during maximal hyperemia and four or five steady-state alterations of aortic pressure in 43 dogs (open-chest, anesthetized preparations) with or without coronary stenoses. The i-HFVP slope index demonstrated no dependence on heart rate, left ventricular end-diastolic pressure, or mean aortic pressure and was highly reproducible within the groups studied (intraclass correlation coefficient, 0.86 for normal arteries, 0.87 for stenotic arteries, and 0.93 for combined groups; for all coefficients, p less than 0.001). The i-HFVP slope index was significantly decreased in the presence of a stenosis (10.3 +/- 3.9 for normal arteries versus 3.6 +/- 1.6 for stenotic arteries, p less than 0.001) as was the transmural m-HFVP slope index (8.9 +/- 4.6 for normal arteries versus 5.3 +/- 3.1, p less than 0.01). Of special importance, the i-HFVP slope index measurement for normal arteries was not significantly different from the transmural and subendocardial m-HFVP slope index measurements (10.3 +/- 3.9 versus 8.9 +/- 4.6 and 9.2 +/- 5.7, respectively). For stenotic arteries, the i-HFVP slope index measurement was also not significantly different from the transmural and subendocardial m-HFVP slope index measurements (3.6 +/- 1.6 versus 5.3 +/- 3.1 and 4.1 +/- 2.3, respectively). The i-HFVP slope index correlated best with subendocardial m-HFVP slope index measurements (correlation coefficient, 0.57; p less than 0.001). When the 95% confidence intervals for the transmural (or subendocardial) m-HFVP slope index in normal arteries were compared with the i-HFVP slope index values, the latter demonstrated a systematic trend to overestimate the m-HFVP slope index. In the presence of a stenosis, this effect was minimized, and the slope values were nearly identical. CONCLUSIONS: The i-HFVP slope index correlates most closely with subendocardial coronary conductance; the index is a hemodynamically independent measure of coronary reserve that is reproducible over a broad range of aortic pressures; and the methodology is applicable to an intact circulation in experimental preparations and may with future developments also prove useful in humans.

Analysis of Variance↗
PubMed1991

A monoclonal antibody against the platelet glycoprotein IIb/IIIa receptor complex prevents platelet aggregation and thrombosis in a canine model of coronary angioplasty.

BACKGROUND: The comparative effects of aspirin and F(ab')2 fragments of monoclonal antibody 7E3 against the platelet glycoprotein IIb/IIIa receptor on ex vivo platelet aggregation and in vivo thrombosis were studied in a canine coronary balloon angioplasty model. METHODS AND RESULTS: Three groups were studied. Group 1 (n = 8) was pretreated with saline placebo, group 2 (n = 8) was pretreated with 325 mg aspirin, and group 3 (n = 8) was pretreated with 0.8 mg/kg 7E3 F(ab')2. Coronary angioplasty was performed in the left anterior descending coronary artery of open-chest dogs under fluoroscopic control; serial measurements of basal and hyperemic coronary blood flows were then made for 2 hours after application of an external stenosis that decreased hyperemic flow by 50%. There were no significant differences in platelet counts or hemodynamic measurements during the experiments. Platelet aggregation was decreased by treatment: group 1, 64 +/- 13% versus 50 +/- 13% (p = NS); group 2, 57 +/- 4% versus 25 +/- 4% (p less than 0.001); and group 3, 77 +/- 5% versus 10 +/- 6% (p less than 0.0002). Compared with initial measurements, the 7E3 antibody was superior to aspirin in maintaining hyperemic coronary blood flow after release of the external stenosis: group 1, 177 +/- 14 versus 21 +/- 14 ml/min (p less than 0.0003); group 2, 189 +/- 9 versus 110 +/- 28 ml/min (p less than 0.008); and group 3, 194 +/- 12 versus 181 +/- 15 ml/min (p less than 0.02). In group 1, arterial occlusion developed in five dogs, and nonocclusive thrombus was seen in three dogs. In group 2, arterial occlusion developed in one dog, and nonocclusive thrombus was seen in five dogs. No thrombotic material was visualized in group 3 dogs treated with 7E3 F(ab')2. CONCLUSIONS: In this animal model, the 7E3 antiplatelet antibody is superior to aspirin in inhibiting platelet aggregation, thrombosis, and acute closure after deep arterial injury caused by coronary balloon angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1991

The epidemiology of fractures of the proximal end of the femur. Change in the incidence among the population at risk in the city of Perugia, Italy between the periods 1975-77 and 1986-88.

The current interest in the epidemiology of fractures of the proximal end of the femur stems from a constant rise in their incidence in Western countries over the past several decades. Many authors believe the explanation could be an increased specific risk factor as well as an aging population. In the city of Perugia, Italy between 1975-77 and 1986-88 the incidence of these fractures increased by 108%, although the number of residents over 60 years of age increased by only 25%. An especially remarkable increase was seen in women over 70 and in intertrocherantic fractures. This information together with the National Institute of Statistics' (ISTAT) demographic forecasts regarding the aging Italian population lead to alarming epidemiologic projections for the next several decades. We propose two possible explanations for this increased risk factor: an increase in the frequency of falls suffered by elderly people and a deterioration in the quality of their bone.

Accidental Falls↗
PubMed1991

Comminuted articular fractures of the distal radius. Results of conservative treatment.

Fifty-nine comminuted articular fractures of the distal radius which had received conservative treatment were reviewed after an average of 3 1/2 years. The results--excellent in 15 patients, good in 30, fair in 12, and poor in 2--were closely linked to the quality of the articular reduction. In patients with a residual malalignment greater than 2 mm, a relatively high incidence of both degenerative arthritis (31%) and unsatisfactory results (56%) was found. The presence of a "die punch" fragment often precluded acceptable fracture reduction and was therefore responsible for many poor clinical and radiographic results. The quality of the extraarticular reduction proved to be of little importance to the final outcome.

Adult↗
PubMed1991

Survivorship of the Total Condylar I prosthesis: Results of a series of 100 total knee arthroplasties.

The Total Condylar knee prosthesis was employed at our institution from April 1975 to October 1986; currently the posterior stabilized type is in use. The results of 100 knee arthroplasties using the Total Condylar I prosthesis, 83 of which were reviewed after an average of 7 1/2 years (maximum 14), were rated good or excellent in 82% of the subjects. Three cases were considered failures due to infection or aseptic loosening. According to the survivorship analysis, there is a 14-year success rate of 93%.

Aged↗
PubMed1990

Comparison of automated quantitative coronary angiography with caliper measurements of percent diameter stenosis.

Measurement of coronary artery stenosis is an invaluable tool in the study of coronary artery disease. Clinical trials and even day-to-day decision making should ideally be based on accurate and reproducible quantitative methods. Quantitative coronary angiography (QCA) using digital angiographic techniques has been shown to fulfill these requirements. Yet many laboratories have abandoned visual analysis in favor of the intermediate quantitative approach involving hand-held calipers. Thus, the purpose of this study was to determine the relation between QCA and the commonly used caliper measurements. Percent stenosis was assessed in 155 lesions using 3 techniques: QCA, caliper measures from a 35-mm cine viewer (cine) and caliper measures from a video display (CRT). Good overall correlation was noted among the 3 different techniques (r greater than or equal to 0.72). Both of the caliper methods underestimated QCA for stenosis greater than or equal to 75% (p less than or equal to 0.001) and overestimated stenosis less than 75% (p less than 0.05). Reproducibility assessed in 52 lesions by independent observers showed QCA to be superior (r = 0.95) to either of the caliper measurements (cine: r = 0.63; CRT: r = 0.73). Therefore, the commonly used caliper method is not an adequate substitute for QCA because overestimation of noncritical stenoses and underestimation of severe stenoses may occur and the measurements have poor reproducibility. These factors definitely preclude its use in rigorous clinical trials. Moreover, since they do not appear to overcome known deficiencies of visual analysis, caliper measurements for day-to-day clinical use must also be seriously questioned.

Cineangiography↗
PubMed1990

Effects of video frame averaging, smoothing and edge enhancement on the accuracy and precision of quantitative coronary arteriography.

Digital analysis of cine film provides numerous options for altering images by frame averaging or filtering algorithms that either smooth or enhance edges. While these may subjectively enhance image quality, there is no uniformity in their use among laboratories and effects on quantitative coronary analysis may not be ideal. To determine which processing algorithms might help or hinder quantitative coronary arteriography, cine film images of precision drilled stenotic cylinders (0.83 to 1.83 nm diameter) implanted in dog coronary arteries were analyzed with and without such algorithms. Video frame averaging of 1 to 49 frames had no effect on measures of accuracy (mean differences) but precision (standard deviation of mean differences) was improved from 0.23 to 0.17 mm (p less than 0.05) with video averaging of greater than or equal to 25 frames. Edge enhancement filtering algorithms resulted in slight deterioration of accuracy and precision and smoothing filtering algorithms caused modest improvements in these parameters; however, these changes were not significantly different from unprocessed images. Using edge enhancement filtering algorithms, accuracy was significantly worse (-0.27 mm) compared to a smoothing filter enhancement algorithm (-0.08 mm, p less than 0.001). The combination of video averaging and smoothing algorithms had no additional beneficial effects. Thus, precision of quantitative coronary analysis of cine film can be optimized by appropriate video averaging. Edge enhancement filtering algorithms should be avoided whereas smoothing filter enhancement algorithms may improve accuracy.

Algorithms↗
PubMed1990

Intravenous recombinant tissue-type plasminogen activator in patients with unstable angina pectoris. Results of a placebo-controlled, randomized trial.

Because thrombus formation may contribute to coronary obstruction in patients with unstable angina pectoris, we performed a pilot investigation to determine whether thrombolytic therapy can relieve coronary narrowing in this acute ischemic syndrome. Sixty-seven patients with rest angina and angiographic evidence of coronary stenosis were randomly assigned to receive either low-dose intravenous recombinant tissue-type plasminogen activator (rt-PA) (0.75 mg/kg over 1 hour), high-dose intravenous rt-PA (0.75 mg/kg over 1 hour; total dose, 100 mg over 6 hours), or intravenous placebo followed by repeat coronary angiography at 24-48 hours to assess change in the severity of coronary narrowing. Each patient also received oral aspirin and intravenous heparin. Mean values of coronary stenosis severity (percent of diameter reduction) declined to a similar extent in each group: placebo, 75 +/- 14% to 72 +/- 14% (p = 0.07); low-dose rt-PA, 75 +/- 16% to 71 +/- 18% (p = 0.03), and high-dose rt-PA, 82 +/- 11% to 77 +/- 17% (p = 0.18), with only the low-dose rt-PA group achieving statistical significance. Resolution of intracoronary filling defects, increase in antegrade flow grade, or both also occurred equally among the three groups. There was considerable variation in individual patient response. Between 29% and 50% of patients within each group demonstrated a decrease in stenosis severity, whereas 50% to 57% noted either improvement in antegrade flow or resolution of intracoronary thrombus. There was no difference in incidence of major bleeding events among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Automated quantitation of indexes of coronary lesion complexity. Comparison between patients with stable and unstable angina.

Analysis of lesion morphology is becoming increasingly important in the study of coronary artery disease. Lesion irregularity has been shown to be one of the most important predictive features for development of myocardial infarction. Most studies to date have used only qualitative assessments of morphology and are thus subject to variability and lack of standardization inherent in subjective visual inspection. We describe a new approach that allows quantitation of lesion morphology. Fifty-nine patients with unstable angina and 17 patients with stable angina were compared. Five morphometric parameters were tested (peaks per centimeter, summed maximum error per centimeter, integrated error per centimeter, number of major features per centimeter, and scaled edge length ratio), four of which were significantly different between the two groups and indicated greater lesion complexity in unstable compared with stable angina patients. No correlation was found between the parameters tested and the degree of luminal narrowing, showing the method's independence from traditional assessments of lesion severity. Excellent intraobserver and interobserver reproducibility was found for all of the parameters. This technique provides a more rigorous approach for analysis of lesion morphology than has previously been available, may provide a method for premorbid detection of high-risk lesions amenable to interventional therapy, and is especially well suited to detect subtle changes in lesion morphology after therapeutic interventions because the parameters are derived on a continuous scale and are not categorical.

Aged↗