Alberto Bestetti

Effects of infusion of glucose-insulin-potassium on myocardial function after a recent myocardial infarction.

We studied the effects of glucose, insulin, and KCI infusion (GIK), on regional myocardial perfusion and function by 99m-Tc-tetrofosmin-gated SPECT. Methods - we studied 21 male patients with their first uncomplicated acute myocardial infarction (AMI). All patients underwent a rest and submaximal stress perfusion study before and after 24-hour infusion of GIK-solution (group A) or saline solution (group B). Results - Group A showed better stress tolerance and ischaemic threshold improvement after GIK infusion whilst no statistical differences were found between basal and post-infusion test in group B. At first the stress test in group A, of the 192 segments analysed, 52 (27%) showed reversible perfusion defect. In group B, of 144 segments analysed, 31 (21%) showed reversible perfusion defect. A postinfusion analysis in group A showed a post-GIK end-diastolic significant count improvement in 21 segments, and a post-GIK end-systolic count improvement in 22 segments. In group B, perfusion increase was observed only in 4 segments, whilst systolic thickening increase was observed only in I segment. Conclusion - these data demonstrate the efficacy of GIK infusion to improve regional myocardial perfusion and function mainly in segments adjacent to the recently infarcted area.

Prognostic implications of stress-induced transient ischemic dilation of the left ventricle in patients with systolic dysfunction and fixed perfusion defects

PURPOSE To verify whether stress-induced transient ischemic dilation (TID) of the left ventricle may help refine prognostic assessment of patients with resting systolic dysfunction and fixed perfusion defects. METHODS Two hundred seventy patients with resting ejection fraction <or=50% and fixed perfusion defects on exercise (n=180) or dipyridamole (n=90) ECG-gated single-photon emission computed tomography (SPECT) were followed-up for the combined endpoint of death, acute coronary syndrome, and clinically-driven revascularization. The TID ratio was defined as the ratio of LV volumes at stress and rest. RESULTS During a median time of 24 months, 47 events (10 deaths, 20 acute coronary syndromes and 17 revascularization) were observed. After adjusting for clinical and stress testing variables, the unfeasible exercise test [hazard ratio (HR) 1.82, 95% confidence interval (CI) 1.02, 3.24] and the highest quartile of TID ratio [HR 1.93, 95% CI 1.05, 3.54] were the only independent predictors of outcome. The highest quartile of TID ratio was associated to significantly lower percent of event-free survival. CONCLUSIONS Left ventricular TID ratio helps refine outcome prediction in patients with resting systolic dysfunction and fixed perfusion defects, thus reducing risk of a false negative result.

Combined assessment of left ventricular perfusion and function by gated single-photon emission computed tomography for the risk stratification of high-risk hypertensive patients.

Objective This study was aimed at verifying whether combined information on left ventricular perfusion and function by electrocardiogram-gated single-photon emission computed tomography (SPECT) retains its known prognostic value in patients with systemic hypertension. Methods A total of 415 hypertensive patients underwent rest and stress (exercise in 278 and dipyridamole in 137) gated 99mTc-sestamibi SPECT and prospective follow-up for the composite endpoint of death and acute coronary syndrome. Patients undergoing revascularization were censored. The individual effect of clinical and stress imaging data on outcome was evaluated by Cox regression analysis. Model validation was performed using bootstrap methods adjusted by the degree of optimism in estimates. Survival analysis was performed using the product-limit Kaplan–Meier method. Results During a median follow-up of 24 months, 12 cardiac deaths and 32 acute coronary syndromes occurred. After adjusting for the most significant covariates, age [hazard ratio (HR) 1.62, 95% confidence interval (CI) 1.02–2.57], diabetes (HR 7.51, 95% CI 1.61–35.2), summed stress score (HR 2.06, 95% CI 1.07–4), and peak end-systolic volume (HR 3.62, 95% CI 1.35–9.69) were multivariable predictors of outcome. The normal perfusion pattern was associated with a low event rate independently of peak end-systolic volume. Conversely, in the case of moderate to severe perfusion abnormalities, a peak end-systolic volume greater than 74 ml was able to identify an increased risk of adverse outcome. Moreover, peak end-systolic volume was significantly higher among patients who died of a cardiac cause compared with those with different outcomes. Conclusion A combined assessment of left ventricular perfusion and function by gated SPECT significantly improves risk stratification in hypertensive patients.

Delayed Gastric Emptying in Advanced Parkinson Disease: Correlation With Therapeutic Doses.

Introduction Gastrointestinal dysfunction is often described in patients with Parkinson disease (PD), and gastrointestinal symptoms are usually attributed to gastroparesis. The consequent delayed gastric emptying (GE) may be an important pharmacokinetic mechanism underlying some of the response fluctuations that develop after long-term levodopa (L-dopa) therapy. The aim of this prospective study was to assess GE time by a liquid meal scintigraphy, in PD patients, and to correlate them with demographic, clinical, and therapeutic data. Methods Scintigraphy with radiolabeled albumin nanocolloids added to acidified orange juice was performed in 51 consecutive PD patients 1 hour after their usual dopaminergic therapy first dose and after a 12-hour fast. Demographic, neurologic, gastrointestinal, and pharmacologic data were collected. Results Fifty-one patients were divided into 2 groups using the cutoff point obtained in normal subjects (40 minutes): group 1 included 29 patients with GE T½ of 27.60 ± 7.30 minutes (normal), group 2 showed a GE T½ of 84.90 ± 53.80 minutes (delayed). The most striking significant difference between the 2 groups was the dopa-decarboxylase inhibitor mean dose that was significantly higher in the group of patients with delayed GE (201.32 ± 97.26 vs 127.65 ± 79.74; P = 0.005). Conclusions The impairment of gastric motility, frequently represented in PD patients, occurs in approximately 42% of patients with motor complications. A mechanism that may explain the GE delay is the effect of L-dopa on dopaminergic receptors in the stomach. Therefore, the dosage of dopa-decarboxylase inhibitor, increasing the L-dopa concentration, may contribute to GE delay and its consequent effect on drug delivery and efficacy.

Removal of radioisotopes in solution and bactericidal/bacteriostatic sterilising power in activated carbon and metal silver filters

Activated carbon filters play an important role in water filtration and purification from contaminants of different origin. Their limit consists in bacterial proliferation, which may occur only during prolonged periods of non-use and in their ability to remove radioactive contaminants present in waste water from Industry or Nuclear Medicine departments. In this work we tested a commercially available activated carbon filter for water purification enriched with silver plated parts incubating in static condition at room temperature different micro organisms (Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Staphylococcus aureus, Aspergillum niger), up to 78 days. The microbial growth was in general more inhibited in the presence of metal silver into the activated carbon in respect to filters with the activated carbon alone: >4log inhibition of bacterial proliferation after 78 days of incubation the presence of silver vs. 2log without silver. When the filters were incubated empty of carbon, the sterilizing power of silver was confirmed further. The activated carbon filters proved also their ability in removing from water the principal radioisotopes used for residues liquid medical and research purposes ((131)I, (99m)Tc, (201)Tl, (67)Ga). These results contribute useful data for the use of the silver-enriched carbon filters in water filtration both for daily use at home, and professional use in a Nuclear Medicine laboratory.

Truncal fat determined by dual-energy X-ray absorptiometry is an independent predictor of coronary artery disease extension

Background Controversy prevails regarding the existence of a correlation between the severity of coronary artery disease (CAD) and the extent and distribution of obesity. Purpose To assess the correlation between total fat, truncal fat (TF), and lean mass, obtained with dual-energy X-ray absorptiometry (DEXA) and standard anthropomorphic indices (body mass index, waist circumference, waist-to-hip ratio) and to verify whether DEXA indices can predict the extent and severity of CAD. Materials and methods Fifty-eight patients (19 females) consecutively referred for coronary angiography underwent physical examination and DEXA assessment of body composition. Results Of the 58 patients enrolled, 22 were overweight and 13 were obese. Significant CAD was found in 39 (67%) patients. DEXA-derived total mass and fat mass enabled us to distinguish overweight from obese patients (P < 0.005), whereas just TF mass correlated with the number of diseased vessels after adjusting for body mass index, sex, age, and smoking habit (odds ratio, 8.68; 95% confidence interval: 1.02-74.10). Conclusion TF determined by DEXA is independently related with CAD extension. Eur J Cardiovasc Prev Rehabil 15:428-433

Enhanced prognostic stratification of CAD patients with low ejection fraction by stress-rest Tc99m tetrofosmin gated-spect.

Objective — This study was performed to assess whether post-stress and rest functional parameters, as measured by gated-SPECT, provide additional predictive value for long-term prognosis, over clinical and perfusion data in patients (pts.) with low left ventricular ejection fraction (LVEF). Methods — 647 consecutive pts. underwent stress/rest gated-SPECT, and 497 were followed for a mean period of 516 ± 264 days. Segmental perfusion and motion/thickening (post-stress and rest) were analysed visually, while EF and LV volumes were calculated using an automatic algorithm (QGS).The post-stress and rest ratio were determined for both end-diastolic (EDV) and end-systolic volume (ESV), while the post-stress LVEF change was calculated subtracting rest-EF from stress-EF. Results — 84/497 pts. showed rest EF < 40%, and 15/84 (18%) experienced a cardiac event (3 cardiac deaths, 1 infarction, 3 hospitalized angina and 9 late revascularizations).The perfusion and functional parameters were not significantly more compromised in pts. with cardiac events compared with pts. without events. Post-stress ESV was the only index significantly higher in pts. with low EF and events compared with pts. with low EF without events (150 ± 72 ml vs. 123 ± 53 ml, P = 0.02). Univariate Cox analysis of clinical, perfusion and functional data showed that the best predictor of cardiac events was stress-ESV (score 6.5, P = 0.01), followed by rest-ESV, rest-EDV, stress-EDV and stress-LVEF. Multivariate analysis demonstrated that the addition of stress-ESV to stress-EF, yielded a significant increase in the global χ2 in the prediction of hard events (cardiac death/infarction) (score 4.634, P = 0.03). Conclusion — In patients with depressed LVEF, stress-ESV was the only independent predictor of long-term outcome.

Novel Application of 3-Dimensional Real-Time Cardiac Imaging to Guide Stem Cell-Based Therapy

Stem cell-based therapy is an emerging treatment for refractory ischemic cardiomyopathy. The transendocardial approach represents the most attractive method that allows direct percutaneous injections of the cell product into the ischemic territories. This clinical case shows a novel strategy designed to optimize cell endocardial delivery, based on the implementation of the 3-dimensional electroanatomical map with the intracardiac-echocardiographic reconstruction of the left ventricle, using acquired multiple slice recordings. Combined imaging was efficacious to detail the anatomical and functional characteristics of the target areas and to guide cell delivery supported by direct real-time visualization of the needle to improve procedural effectiveness and safety.

Understanding coronary atherosclerosis in relation to obesity: is getting the distribution of body fatness using dual-energy X-ray absorptiometry worth the effort? A novel perspective using Bayesian Networks.

AIM A relative excess of fat in the upper body region has been proven to be associated with increased coronary artery disease (CAD) risk. Dual-energy X-ray absorptiometry (DXA) is probably the most accurate and precise method available to study fat regional distribution and to directly measure total body fat and lean soft tissue mass. However, while several studies have investigated the abilities of obesity anthropometric measures in predicting CAD, only few studies have evaluated DXA as CAD predictor; particularly, a comparison between a model including information coming from anthropometric measurements and a model in which fat is precisely measured by DXA, is still lacking. In order to verify if CAD severity, as measured by Gensini score, is better predicted when a prognostic model includes DXA measurements rather than anthropometric measures, we compared performance obtained by two Bayesian Networks (BNs) including standard anthropometric measures and DXA, respectively. METHODS Data come from 58 consecutive patients, 79% of them having suspected and 21% known CAD. Two BNs were implemented: input variables include anamnestic information, biochemical data and obesity measures. In the first model (BN1) obesity was measured by body mass index and waist-to-hip ratio, while in the second one (BN2) it is quantified by DXA-derived parameters. RESULTS Network graphs and results coming from sensitivity analysis show that in both models lipoproteins and biomarkers of inflammation act as proximal node, while obesity (independently of the chosen measure) appears to be a distal node acting by the intermediation of other variables. Both models show high predictive abilities, the mean percentage classification errors being, respectively, 14.13 and 18.87. CONCLUSIONS In our study, the BN predictive ability is slightly superior when obesity is measured using anthropometric data instead of DXA measurements. The reason probably relies on the fact that in the BN the obesity role in predicting CAD is mediated by the action of other factors that appear to be more directly influencing the outcome. Thus, the necessity to dispose of a perfect measure becomes less compulsory and the huge effort to precisely estimate body composition with complex methods as DXA could be avoided when using expert system such as BN as predictive tool.

Severe Cortical and Trabecular Osteopenia in Secondary Hyperparathyroidism

Background:  Peripheral quantitative computed tomography (pQCT) provides real volumetric bone density values, not only of the total, but also of trabecular and cortical bone, separately. In addition, it provides data on bone geometry that can be related to the risk of fracture.