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Biomedical subjects

G B Mancini

Publications and source records attributed to G B Mancini.

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

[Limitation of atherosclerosis in coronary arteries with pravastatin (PLAC 1)].

PLAC 1 is a double-blind, randomized, placebo controlled trial assessing the efficacy of monotherapy with an HMG CoA reductase inhibitor (pravastatin) in altering the atherosclerotic process. This trial was an angiographic trial undertaken in the United States and was completed in early 1994. Despite the fact that angiographic end-points were the prime focus during the planning and execution of the trial, significant impact was seen in the area of clinical events, particularly fatal and nonfatal myocardial infarctions. The latter were significantly reduced in the treated patients. These results were paralleled by a significant slowing of progression in the treated patients. Importantly, the angiographic effects were predominant in prevention of new lesion formation and in slowing the progression of mild/moderate lesions less than 50% diameter stenosis at baseline. Current concepts suggest that the latter two categories of lesions are the most important in linking angiographic outcomes with clinical events. PLAC 1 is the first trial to concomitantly show statistically significant effects in clinical end points and angiographic end-points in the category of new and/or mild stenoses. These results are compatible with the concept of plaque stabilization.

Anticholesteremic Agents↗
PubMed1995

Mechanisms underlying reduction of clinical events in lipid lowering trials.

OBJECTIVE: To outline the emerging hypotheses explaining the reductions in clinical events in trials of lipid lowering. DESIGN: Selective literature review. MAIN RESULTS: The primary angiographic end-points of recent lipid lowering trials, justified largely from a hemodynamic paradigm of coronary disease, have been shown to improve significantly but modestly. The improvements appear out of keeping with the more impressive trends in reducing clinical events. There are many possible explanations for these results. Prominent among these is the influence of lipid lowering on the atherothrombotic and vasomotor processes, including endothelially mediated ones, which underlie both plaque rupture and plaque progression. Additionally, there is now a greater appreciation of the role of constituents of plaques, especially moderate ones, in rendering lesions either susceptible or resistant to acute disruption. In aggregate, these newer areas of emphasis have led to the concept of plaque stabilization. CONCLUSIONS: Plaque stabilization is a new concept encompassing many functional and morphological factors that are influenced in the short and long term by aggressive lipid lowering. This concept may help explain reductions in clinical events noted in lipid lowering trials.

Arteriosclerosis↗
PubMed1994

Iodixanol, a new isosmotic nonionic contrast agent compared with iohexol in cardiac angiography.

Iodixanol, a new ratio 6 nonionic iodinated contrast agent with an osmolality equal to serum, was compared with iohexol in a randomized, double-blind, parallel study. Two hundred patients undergoing elective diagnostic cardiac angiography were randomized to iodixanol (n = 101) or iohexol (n = 99). There were no differences noted between the 2 agents in the mean changes in systolic or diastolic blood pressure or heart rate during or immediately after any angiography. However, significantly more patients had a decrease in diastolic blood pressure of > 20 mm Hg during left coronary angiography with iodixanol. The only significant differences in any electrophysiologic parameter were slightly more PR prolongation during left coronary angiography with iodixanol and more ST-segment depression with iohexol during coronary angiography. Neither was clinically significant. Injection-associated discomfort occurred with both agents, but more patients experienced moderate to severe discomfort with iohexol (52%) than with iodixanol (17%) (p < 0.001). Only 1 potentially serious adverse event, ventricular fibrillation with iohexol, was considered related to contrast, and there were no differences noted between the agents. Overall, angiographic quality was equal with all angiograms being assessed as good or excellent in both groups (p = 0.885). In this low-risk population undergoing cardiac angiography, iodixanol is safe and effective without clinically important differences from iohexol. Additional studies in patients at high risk for complications should help further define the role of iodixanol in cardiac angiography.

Blood Pressure↗
PubMed1994

Early and late displacement of fractures of the distal radius. The prediction of instability.

One hundred fractures of the distal radius with dorsal displacement were treated by closed reduction and a plaster cast. The mean age of the patients was 55 years. Radiographs were taken after 1, 2 and 5 weeks to evaluate the frequency of early and late displacement. Dorsal angulation occurred in 71 patients, shortening of the radius in 47 and flattening of the radial angle in 32. Late displacement was more frequent than early. Statistical analysis showed a greater incidence of secondary shortening in Older's types III and IV fractures. The severity of the initial radial shortening was the most reliable indication of instability.

Chi-Square Distribution↗
PubMed1994

[Arthroplasty of the knee using total condylar prosthesis. Long term results (10 to 17 years) and survival analysis].

INTRODUCTION: This study refers to the first 76 Total Condylar knee prostheses that were implanted in 66 patients, with a minimum follow-up of 10 years. MATERIALS AND METHODS: There were 54 women and 12 men with an average age of 65 years (range 45-81). The diagnosis was osteoarthrosis in 63 knees and rheumatoid arthritis in 13. We were able to review 54 prostheses with an average follow-up of 13 years (10-17) using the rating system of the Hospital for Special Surgery and the Survivorship analysis. RESULTS: The results were excellent and good in 72.5 per cent knees and fair and poor in 22 per cent, 3 knees (5.5 per cent) had been revised for deep infection in 2 cases and for aseptic loosening in 1. Pain at rest was absent or mild in all but one patient; walking pain was absent in 32 knees (63 per cent), mild in 12 (23 per cent), moderate in 5 (10 per cent) and severe in 2 (4 per cent). Average range of motion was 89 degrees, ranging from 40 degrees to 120 degrees. A flexion contracture greater 5 degrees was seen in 8 knees (16 per cent). Instability in the frontal plane tested in full extension was more than 5 degrees in 10 patients (19.5 per cent). A significant deterioration of the results occurred in the last 4-5 years, since in 1988 excellent and good results were still 82 per cent. A loss of postoperative alignment of 5 degrees or more was observed in 11 knees: aseptic loosening was identified in 2 of these cases and deformation of the tibial component was seen in 1 knee. In the remaining 8 knees we observed increased lateral instability, compared to the postoperative evaluation. In this group of 8 knees we measured in the AP view the thickness of the tibial component on the lateral and medial side. We found polyethylene wear on the medial side in 4 cases. Ten of the 11 knees with loss of alignment had an early postoperative femoro-tibial axis less than 5 degrees. We observed radiolucent lines in 18 patellar and 27 tibial components. A width greater than 2 mm, correlated to an extension to 5 or more zones, was seen in 3 tibial components with aseptic loosening. Survivorship analysis using aseptic loosening, mechanical failure of the polyethylene and deep infections as end point gave a cumulative success rate at 10 years of 92 per cent% with 95 per cent confidence interval ranging from 85.1 to 98. DISCUSSION: Our study reports a lower percentage of excellent and good results if compared to other series of Total Condylar prosthesis with a comparable follow-up. A significant deterioration of the results occurred in the last years, but this was often not related to the knee itself but to poor general conditions in some patients. In this series there is a relevant number of knees with a post-operative alignment that today we don't consider correct and all the aseptic loosenings occurred in knees with a tibial component positioned in varus. CONCLUSION: Survivorship analysis gave a cumulative success rate comparable with those reported in other studies and confirmed the durability and longevity of this model of prosthesis.

Aged↗
PubMed1993

Design and recruitment in the United States of a multicenter quantitative angiographic trial of pravastatin to limit atherosclerosis in the coronary arteries (PLAC I).

The present study was designed to test the effect of pravastatin, a new, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on the progression of coronary artery disease in patients with moderate hypercholesterolemia. Angiographic entry criteria included the presence of > or = 1 stenosis > or = 50% in a major epicardial coronary artery, and certification of film quality through the core angiography laboratory. Patients qualified for randomization if after diet stabilization their low density lipoprotein cholesterol concentrations were > or = 130 and < 190 mg/dl, and triglycerides were < or = 350 mg/dl. Pravastatin (40 mg) or placebo is administered once daily at bedtime. Arteriography will be repeated at the end of 3 years of treatment. The primary end point of the study is the change in absolute mean coronary artery diameter. During a 30-month recruitment period, 44,145 patients were screened, and 408 were randomized. The most frequent reason for excluding patients during the screening and dietary lead-in periods was a low serum cholesterol level. A large proportion of patients with documented coronary artery disease have cholesterol concentrations that are considered to be normal or only modestly increased. Adherence to strict standards of quality control for digital analysis of angiograms ensures that baseline angiograms can be interpreted at the end of 3-year follow-up.

Adult↗
PubMed1993

Sensitivity and reproducibility of the instantaneous hyperemic flow versus pressure slope index compared to coronary flow reserve for the assessment of stenosis severity.

The objective of this study was to compare the reproducibility and sensitivity of the instantaneous hyperemic flow versus pressure slope index (i-HFVP) and coronary flow reserve (CFR). The i-HFVP is the slope of the relationship between diastolic hyperemic coronary flow and diastolic aortic pressure, normalized for bed weight. In contrast to CFR (the ratio of hyperemic to basal coronary flow), the i-HFVP has been shown to be independent of changes in aortic pressure, heart rate, contractility, and preload. To compare reproducibility, i-HFVP and CFR were measured three times in eight dogs instrumented with high-fidelity micromanometers and flow probes, allowing for full hemodynamic recovery between phases (15 to 40 minutes). Maximum hyperemia was induced with intravenous adenosine. The sensitivity of i-HFVP and CFR was assessed in 16 instrumented dogs. Measurements were performed for one basal state and for five subcritical incremental stenoses created with a screw occluder during hyperemia. Intraclass variability correlation coefficients were 0.96 for i-HFVP but only 0.56 for CFR. Both i-HFVP and CFR showed significant decrements with each increasing stenosis. However, the percentage reductions at each level were significantly greater for the i-HFVP. The difference in percentage reduction favoring increased sensitivity of the i-HFVP ranged from 11% to 23%. It was concluded that the i-HFVP is more reproducible and more sensitive to the presence of stenoses than CFR.

Animals↗
PubMed1993

Early reocclusion after successful thrombolysis is related to lesion length and roughness.

BACKGROUND: Reocclusion is a significant problem after thrombolysis. Results of previous studies conflict regarding the association of various features of postlytic lesions that might predict reocclusion. METHODS: A computer-assisted algorithm was therefore used to quantitatively measure edge roughness in the 90-minute postlysis angiogram of 84 patients receiving recombinant tissue plasminogen activator within 6 hours of chest pain. RESULTS: Twenty-five patients had reocclusion, and 59 did not. The baseline angiogram showed no differences between these two groups with respect to minimal dimensions or relative percentage of stenosis. Length was greater in the reocclusion group (12.2 +/- 5.0 vs 10.0 +/- 4.2 mm, P < 0.05). Three of four roughness indices based on curvature analysis indicated greater roughness in those patients with reocclusion. These differences were largely due to the increased length of these lesions. The scaled edge-length ratio, an index of roughness that is independent of length, was, however, significantly greater in the reocclusion group (1.15 +/- 0.10 vs 1.09 +/- 0.08, P < 0.006). Multiple regression analysis showed that lesion length, the scaled edge-length ratio, and the number of features (invaginations and evaginations) per cm correlated independently with the risk for reocclusion. CONCLUSIONS: The length and roughness of postlytic residual lesions are determinants of reocclusion.

Algorithms↗
PubMed1992

Tachycardia, contractility and volume loading alter conventional indexes of coronary flow reserve, but not the instantaneous hyperemic flow versus pressure slope index.

OBJECTIVES AND BACKGROUND: Because measurements of flow reserve are often made in the setting of fluctuating hemodynamic variables that cause alterations in basal or hyperemic coronary blood flow, traditional flow reserve indexes may be difficult to interpret. Prior work in this laboratory has suggested that the instantaneous hyperemic flow versus pressure slope index is a more hemodynamically stable alternative to measures of flow reserve. Although this index has no hemodynamic dependence on changes in aortic pressure, the extent to which it is affected by other factors that alter myocardial work is unknown. Therefore, the purpose of this investigation was to analyze the effects of tachycardia (induced by atrial pacing at 10 beats/min above the basal heart rate), dobutamine infusion (10 micrograms/kg per min) and saline solution volume loading (500 ml) on measurements of traditional coronary flow reserve, the resistance reserve ratio and the instantaneous hyperemic flow versus pressure slope index. METHODS: Twenty-nine open chest anesthetized dogs were studied in four sequential stages: baseline, tachycardia, dobutamine infusion and saline solution volume loading. Traditional coronary flow reserve was defined as the ratio of hyperemic coronary blood flow to basal coronary blood flow, the resistance reserve ratio as the ratio of basal coronary resistance to hyperemic coronary resistance and the instantaneous hyperemic flow versus pressure slope index as the slope of the instantaneous relation between diastolic hyperemic coronary blood flow and diastolic aortic pressure normalized by perfusion bed weight. Hyperemia was induced by intravenous adenosine infusion (1 mg/kg per min). Mean aortic pressure was kept nearly constant during the interventions by manipulation of an aortic clamp or a vena caval snare. RESULTS: The final study group comprised 18 open chest dogs. Coronary flow reserve was significantly decreased by tachycardia (3.7 +/- 1.2 to 3.0 +/- 1.2, p < 0.0001), decreased by saline solution volume loading (3.2 +/- 1.3 vs. 2.7 +/- 0.8, p = 0.06) and significantly increased by dobutamine infusion (3.2 +/- 1.3 to 4.3 +/- 1.5, p < 0.0005). In contrast, the instantaneous hyperemic flow versus pressure slope index was not affected by the three interventions (7.4 +/- 3.1 vs. 7.3 +/- 3.3, 7.4 +/- 3.2 vs. 7.4 +/- 3.4 and 7.5 +/- 3.1 vs. 7.3 +/- 3.4, respectively, all p = NS). The changes observed in the resistance reserve ratio were of similar or greater magnitude and significance to the changes in coronary flow reserve. CONCLUSIONS: The instantaneous hyperemic flow versus pressure slope index offers a hemodynamically stable alternative to measures of vascular reserve because it is independent of moderate changes in heart rate, contractility and volume loading that may occur commonly in clinical situations.

Analysis of Variance↗
PubMed1992

Prognostic importance of quantitative analysis of coronary cineangiograms.

Many studies have shown the prognostic value of angiographic data, but few have examined quantitative parameters of wall motion and shape or coronary stenosis severity. To determine whether these parameters have prognostic importance, baseline angiograms of 283 patients with up to 11.2 years (mean 8.3) of follow-up were quantitated. Event-free survival curves were constructed using log-rank testing. These indexes were also considered in 2 predictive models (Cox regression models): 1 with ("clinical") and 1 without ("quantitative") subjective angiographic analysis and clinical information. Regional shape (anterior and inferior walls) and motion (anterior wall only) indexes were predictive of event-free survival when considered singly. But these parameters were not of independent prognostic importance in the regression models. The most important independent parameters in the quantitative model for predicting overall cardiac mortality or an initial lethal cardiac event were the ejection fraction and the percent diameter narrowing of each major coronary artery. Myocardial infarction was predicted by the percent diameter stenosis of the left main and left anterior descending arteries but not the ejection fraction. In the clinical model, the factors of overriding prognostic importance were the ejection fraction and the subjective determination of the number of vessels involved with "significant" stenoses. Quantitative coronary arteriography still contributed independent prognostic value. Thus, quantification of the ejection fraction and severity of coronary lesions were of independent, prognostic importance, whereas indexes of regional function and shape were not.

Adult↗
PubMed1992

Establishing comprehensive, quantitative criteria for detection of restenosis and remodeling after percutaneous transluminal coronary angioplasty.

To establish comprehensive criteria for detecting restenosis and remodeling, inter- and intraobserver reproducibility of quantitative arteriography in the analysis of 20 lesions immediately after and 6 months after percutaneous transluminal coronary angioplasty (PTCA) were assessed. Geometric single-plane (minimum, maximum, mean diameter and percent diameter stenosis), biplane (absolute and relative cross-sectional area stenosis), relative densitometric area stenosis and the average of densitometric area stenosis in orthogonal views were compared. A high intra- and interobserver reproducibility of all absolute measurements was found, with the highest correlations for minimum diameter and cross-sectional area (interobserver, r = 0.85 and 0.85; intraobserver, r = 0.93, and 0.95 for minimum diameter and cross-sectional area, respectively). Of the relative measurements, biplane geometric percent cross-sectional area stenosis was the most reliable and percent densitometric area stenosis was the most variable (interobserver, r = 0.67; intraobserver, r = 0.71). Only small differences were demonstrated for the absolute measurements between the analysis of lesions immediately after PTCA and after follow-up, whereas a greater variability was found for relative measurements, especially videodensitometry. In both circumstances, a poor correlation between relative densitometric cross-sectional area from orthogonal views was found, whereas geometric elliptical cross-sectional area correlated quite well with the average of densitometric percent cross-sectional area in orthogonal views (interobserver, r = 0.86; intraobserver, r = 0.84). Thus, data in this study support the suitability of geometric quantitative analysis for the assessment of PTCA results. Densitometry was the least reliable quantitative parameter.

Analysis of Variance↗
PubMed1992

Long-term results and survivorship analysis of 89 total condylar knee prostheses.

The results of 89 total condylar I prostheses were assessed using both the Hospital for Special Surgery rating system and survivorship analysis. At an average follow-up period of 9.5 years (range, 5-15) 61 patients (72 knees) were available for clinical and radiographic evaluation. Thirty (41.5%) knees were rated as excellent, 29 (40.5%) good, 4 (5.5%) fair, and 6 (8.5%) poor. Three (4%) cases were considered failures because they needed a second operation. Loss of the postoperative alignment often associated with lateral instability was observed in 23 knees. Loosening of the tibial plateau occurred in two knees; in one of these a successful revision was performed. Survivorship analysis, using deep infection and aseptic loosening as end-point criteria, gave a 15-year probability of survival of 95%. These results confirm the validity of the total condylar prosthesis and the reliability of cementation in knee arthroplasty.

Actuarial Analysis↗
PubMed1992

Clinical value of digital radiographic coronary quantification: comparison with visual assessment and coronary flow reserve.

The value of quantitative assessment of coronary artery dimensions at the site of the most critical coronary stenosis was assessed by comparison with the correspondent reactive hyperaemia as measured by digital subtraction angiography and with the functional results. Thirty-two coronary lesions were analysed and flow reserve data were obtained in an additional 11 vascular distributions without coronary obstruction in 19 patients. Minimal diameter less than 1.25 mm and minimal area less than 1.5 mm2 at the site of the stenosis best separated vascular distributions with inadequate hyperaemic response from those with sufficient reactive hyperaemia (chi 2 = 19.57; P less than 0.0001). Identification of lesion severity based on videodensitometric percentage area stenosis greater than 70% or percentage diameter stenosis greater than 50% yielded similar but poorer results (respectively chi 2 = 14.53; P less than 0.001 and chi 2 = 10.29; P less than 0.005). Additionally, when visually determined percentage stenosis was compared to the quantitatively assessed value, only a fair correlation was observed (r = 0.74), with visual overestimation of lesion severity by an average of 11.1 +/- 9.8% (mean +/- SD). Reactive hyperaemia in vessels with coronary obstruction could be described from minimal coronary dimensions by a quadratic equation but did not correlate closely in this patient population (r = 0.54 with minimal diameter and r = 0.58 with minimal area).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography, Digital Subtraction↗