Search PubMed⌕ Search

Biomedical subjects

C Anagnostopoulos

Publications and source records attributed to C Anagnostopoulos.

At least 37 records · Page 2Linked to original sources
PubMed1998

Left ventricular long axis disturbances as predictors for thallium perfusion defects in patients with known peripheral vascular disease.

OBJECTIVE: To compare resting long axis echocardiography with adenosine thallium-201 emission tomography in detecting myocardial ischaemic abnormalities in patients before peripheral vascular surgery. DESIGN: A prospective and blinded preoperative examination of resting left ventricular minor and long axes and myocardial perfusion during adenosine vasodilatation using thallium-201 emission tomography. SETTING: A tertiary referral centre for cardiac and vascular disease equipped with invasive, non-invasive, and surgical facilities. SUBJECTS: 65 patients (40 men) with significant peripheral vascular disease, mean (SD) age 63 (10) years, and 21 control subjects of similar age. METHODS: Segments were classified as normal, with fixed or reversible defects according to thallium-201 myocardial perfusion tomography. Systolic long axis abnormalities were either reduced excursion and/or abnormal shortening after A2, and diastolic abnormalities either delayed onset of lengthening > 80 ms and/or reduced peak lengthening rate < 4.5 cm/s. Segmental perfusion defects were compared with the equivalent long axes; anteroseptal for septal, inferoseptal for posterior, and lateral for left side giving a total of 195 segments. RESULTS: Systolic long axis abnormalities predicted fixed thallium defects (sensitivity 86%, specificity 87%, positive predictive value 0.78, negative predictive value 0.93, p < 0.001), and diastolic abnormalities correlated with reversible perfusion defects (sensitivity 90%, specificity 85%, positive predictive value 0.72, negative predictive value 0.95, p < 0.001). Echocardiography characteristics of the true and false positive segments were not different in the site or the extent of abnormalities. CONCLUSION: Systolic long axis abnormalities predict fixed and diastolic reversible thallium perfusion defects in patients with peripheral vascular disease. Ventricular long axis may thus have a value as a screening test before peripheral vascular surgery as well as providing a means of monitoring myocardial perfusion. The high negative predictive values indicate that a negative long axis study makes significant perfusion abnormalities very unlikely in patients with high pretest probability of coronary artery disease.

Adenosine↗
PubMed1997

[Tuberculous pneumopathy in the course of cystic fibrosis].

BACKGROUND: Tuberculosis is rarely seen in patients with cystic fibrosis. CASE REPORT: A 14-year old female adolescent, regularly followed for a well-tolerated form of cystic fibrosis, developed an acute respiratory infection with consolidation of the left inferior lobe, and no response to the usual antibiotic treatment of cystic fibrosis. Mycobacterium tuberculosis was found in aspirate by fibroscopy, on Loewenstein medium. No familial or social infection contact were identified. Antituberculous chemotherapy with three drugs brought about a prompt improvement of sytemic signs, weight gain, resolution of pulmonary foci and sedation of biological findings referable to inflammation. CONCLUSION: This case report reminds us that tuberculosis may occur in cystic fibrosis patients. Loewenstein cultures should routinely be made when faced with an unexplainable worsening of the condition.

Adolescent↗
PubMed1997

An algorithm for real-time, continuous evaluation of left ventricular mechanics by single-beat estimation of arterial and ventricular elastance.

We describe a computer algorithm that allows continuous, real-time evaluation of ventricular elastance (Ees), arterial elastance (Ea), and their coupling ratio in a clinical setting. In the conventional pressure-volume analysis of left ventricular (LV) contractility, invasive methods of volume determination and a significant, rapid preload reduction are required to generate Ees. With the help of automated border detection by transesophageal echocardiography, and a technique of estimating peak LV isovolumic pressure, Ea and Ees were determined from a single cardiac beat without the need for preload reduction. A comparison of results obtained by a conventional approach and the new algorithm technique, showed good correlation for Ea (r = 0.86, p < 0.001) and Ees (r = 0.74, p = 0.001). Bias analysis showed a bias (d) of 1.47 mmHg/cm2 for Ea with a standard deviation (SD) of 7.03 mmHg/cm2, and upper (d+2SD) and lower(d-2SD) limits of agreement of 15.24 mmHg/cm2 and -12.31 mmHg/cm2, respectively. Bias analysis showed a bias of -1.42 mmHg/cm2 for Ees with a SD of 4.88 mmHg/cm2, and limits of agreement of 8.15 mmHg/cm2 and -10.98 mmHg/cm2. The algorithm's stability to artifacts was also analyzed by comparing magnitudes of residuals of Ea and Ees from source signals with and without noise. With Ea differing by an average of 1.036 mmHg/cm2 and Ees differing by an average of 0.836 mmHg/cm2, the algorithm was found to be stable to artifacts in the source signals.

Algorithms↗
PubMed1997

Gated technetium-99m-tetrofosmin SPECT and cine MRI to assess left ventricular contraction.

UNLABELLED: This study investigates the value of ECG-gated 99mTc-tetrofosmin SPECT in the assessment of resting left ventricular (LV) function by comparison with cine MRI. METHODS: Twenty-eight patients were recruited prospectively from those referred for routine myocardial perfusion scintigraphy. Eight had three-vessel coronary artery disease, two had two-vessel disease, five had single-vessel disease and thirteen had not previously undergone coronary angiography. Twelve patients had previous myocardial infarction. After i.v. injection at rest of 750 MBq 99mTc-tetrofosmin, ECG-gated tomograms (16 frames per cardiac cycle) were acquired after 30 min. A nine-segment model of the LV was used and images were interpreted by two observers independently. Wall motion was assessed using a six-point scale (including unclassified where no judgment was possible), and systolic wall thickening was assessed from count changes through the cycle using a five-point scale. Tracer uptake was scored using a four-point scale. Diastolic wall thickness was assessed using a four-point scale. Cine magnetic resonance images were acquired in the same planes and analyzed in an identical fashion. RESULTS: There was good overall agreement between the techniques for wall motion, thickness and thickening (kappa = 0.55-0.66), although 15 of the 252 (6%) segments were unclassified on radionuclide imaging. While there was absolute agreement in the assessment of all parameters in 10 patients with normal wall motion by MRI, agreement was less good in the 8 patients with three-vessel disease and poor left ventricular function (mean LVEF = 26%, mean LVEDV = 241 ml) (kappa = 0.37-0.48). Where tracer uptake was normal, there was good agreement between imaging, techniques (kappa = 0.64-0.75), but where uptake was absent or nearly absent, agreement was poor (kappa = 0-0.61), and 15 of 22 segments were unclassified on SPECT. CONCLUSION: Gated 99mTc-tetrofosmin imaging provides an accurate assessment of myocardial wall motion, thickening and thickness in normal left ventricles but is less valuable in poorly functioning ventricles. Six percent of segments could not be assessed because of inadequate tracer uptake.

Adult↗
PubMed1997

Antibiotic prophylaxis in cardiac surgery.

BACKGROUND: A prospective, randomised study was conducted among 1009 cardiac surgery patients in order to compare the prophylactic efficacy of a second generation cephalosporin (cefuroxime) given as single shot, versus a broad spectrum double regimen (amoxycillin-netilmicin). METHODS: Cefuroxime received 501 patients (Group A), while a 4-day combination of amoxycillin-netilimicin 508 patients (Group B). RESULTS: There were found no statistically significant differences either in infection rate or the kind of infection between the two groups. Single shot cefuroxime prophylaxis was just as effective, as a 4-day combination of amoxycillin and netilmicin. Total infection rate was 5.6% (n=28) in Group A and 5.7% (n=29) in Group B. Respiratory tract infection was the most frequently registered in both groups; 2.6% in Group A and 2.9% in Group B. Sternal wound and catheter-related infection rates were 0.6% and 1% in both groups, respectively. There were no side effects due to the given antibiotics. CONCLUSIONS: A single shot of cefuroxime prophylaxis is equally effective and safe as a 4-day regimen with amoxycillin and netilmicin.

Aged↗
PubMed1996

Regional myocardial motion and thickening assessed at rest by ECG-gated 99mTc-MIBI emission tomography and by magnetic resonance imaging.

We have validated ECG-gated emission tomography using technetium-99m methoxyisobutylisonitrile for the assessment of regional ventricular function by comparing it with cine magnetic resonance imaging (MRI). Gated tomography was performed at rest in 24 patients referred for myocardial perfusion imaging [17 males and seven females with a mean age of 58 years, nine of whom had had a previous myocardial infarction (MI)]. Scores were assigned to each of nine myocardial segments for wall motion and for thickening. Cine MRI was analysed in an identical fashion. Four out of 216 (2%) segments were uninterpretable by gated tomography because of inadequate tracer uptake. In eight patients without coronary artery disease (CAD), wall motion and thickening were normal by both methods. Gated tomography showed abnormal wall motion or thickening in all patients with previous MI and in five of seven patients with CAD but no prior MI. Association between wall motion and thickening was good (rs=0. 86). Overall, there was good agreement between gated tomography and MRI for both wall motion (178/212 segments, kappa=0.66) and wall thickening (184/212 segments, kappa=0.69). In segments with severely reduced perfusion, however, there was poorer agreement (kappa=0.31). Interobserver and intraobserver agreement was high (kappa from 0.61 to 0.78). Thus, in patients investigated for CAD, there is good overall agreement between gated tomography and MRI but the agreement is lower in segments with severe perfusion defects.

Coronary Disease↗
PubMed1995

A comparison of resting images from two myocardial perfusion tracers.

We have compared stress-redistribution and delayed rest thallium-201 with rest technetium-99m methoxyisobutylisonitrile (MIBI) tomograms in order to compare the tracers for the assessment of myocardial viability and to validate a rapid protocol combining the two tracers. We studied 30 consecutive patients with known or suspected coronary artery disease [group 1: 16 with normal left ventricular function, mean left ventricular ejection fraction (LVEF) 55%, SD 6%; group 2: 14 with abnormal function, mean LVEF 28%, SD 8%]. 201Tl was injected during infusion of adenosine followed by acquisition of conventional stress and redistribution tomograms. On a separate day, 201Tl was injected at rest with imaging 4 h later. 99mTc-MIBI was then given at rest and imaging was performed. Three images were compared: redistribution 201Tl, rest 201Tl, and rest 99mTc-MIBI. Tracer activity was classified visually and quantitatively in nine segments and segments with > 50% activity were defined as containing clinically significant viable myocardium. Mean (+/- SD) global tracer uptake as a percentage of maximum was similar in group 1 (rest 201Tl 69% +/- 12%, redistribution 201Tl 69% +/- 15%, rest 99mTc-MIBI 70% +/- 13%, ANOVA P > 0.05), but in group 2 mean tracer uptake was significantly greater in the rest 201Tl images (59% +/- 16%) than in redistribution 201Tl images (53% +/- 17%) or rest 99mTc-MIBI images (53% +/- 19%) (ANOVA P = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1995

Clinical significance of technetium-99m methylene diphosphonate myocardial uptake: association with carcinoma of the prostate.

Benign myocardial uptake of technetium-99m labelled phosphates, not related to cardiac or metabolic disorders, has been documented except in the case of 99mTc-methylene diphosphonate (MDP). The aim of this study was to assess the frequency of myocardial uptake and its possible association with malignant tumours in general and prostatic carcinoma in particular. We reviewed bone scintigrams performed with either 99mTc-hydroxydiphosphonate (HDP) or 99mTc-MDP over a period of more than 2 years for all patients with prostatic carcinoma and a matching group of patients suffering from other malignant and non-malignant disorders. A total of 965 scintigrams of 812 patients (males = 559, females = 253; age range 50-91 years, average age 69.2 years) were reviewed. Increased myocardial uptake was detected in 19 scintigrams (MDP = 13, HDP = 6) of 18 patients (17 males, one female). Most of the male patients with increased myocardial uptake had prostatic carcinoma (13/17) and were over 80 years of age (12/17). All patients were free of any cardiac or noncardiac disorder that might account for such uptake. When scintigraphy was repeated in the same patient, the uptake of 99mTc-HDP was more diffuse and of higher grade than that of 99mTc-MDP. "Benign" myocardial uptake of 99mTc-MDP is more common than previously thought. Although uptake of radiophosphates is attributed to asymptomatic atherosclerotic changes associated with old age, a strong association with prostatic carcinoma exists which may indicate variations in the bone: soft tissue affinity of different MDP complexes.

Aged↗
PubMed1995

Avoidance of upward creep artifact during TI-201 myocardial perfusion tomography using adenosine infusion. A case report.

Upward motion of the heart during tomographic data acquisition of stress TI-201 myocardial perfusion images may lead to artifacts in the reconstructed tomograms. The authors report a patient in whom this occurred, giving the impression of reversible perfusion defects. Although correction of the raw data abolished the artifact, a separate study using adenosine vasodilation produced normal images. The authors conclude that adenosine vasodilation should be considered in preference to dynamic exercise in patients at risk of this artifact, such as those with a high exercise tolerance.

Adenosine↗
PubMed1993

Thallium myocardial perfusion tomography using intravenous dipyridamole combined with maximal dynamic exercise.

Exercise thallium imaging is effective and provides information on exercise tolerance and symptoms, but is less sensitive if exercise is submaximal. When dipyridamole alone is used for such patients, the exercise parameters are lost and high background uptake results. This study examines dipyridamole combined with maximal exercise, to capitalize on the strengths of both techniques. Thallium tomography was performed in 122 patients with dipyridamole (group 1), exercise (group 2), or dipyridamole with maximum exercise (group 3). In patients with coronary artery disease, thallium tomography was abnormal in 92, 93 and 95% (P = ns), with reversible ischaemia in 82, 81 and 84% (P = ns) in the three groups, respectively. Among patients in groups 2 and 3 who exercised submaximally, detection of individual arterial stenoses was improved in group 3 (P < 0.05) and larger defects were found (2.4 versus 4.2 segments, P < 0.01). In group 3, no serious complications occurred and fewer vasodilatory side effects were seen than in group 1 (P < 0.01). The heart to splanchnic count ratio in groups 2 and 3 (1.61 versus 1.65, P = ns) was significantly greater than in group 1 (1.28, P < 0.0001). Compared with exercise alone, additional dipyridamole improved diagnostic accuracy in patients with limited exercise potential. Compared with dipyridamole alone, additional exercise provided useful exercise information, reduced vasodilatory side effects and improved scan quality. Combined dipyridamole and exercise stress is safe, and could be used routinely, but a larger study is required to establish if there is an overall diagnostic improvement.

Adult↗
PubMed1993

Liver cirrhosis in cystic fibrosis--therapeutic implications and long term follow up.

Experience gained from liver studies in 450 patients with cystic fibrosis, seen in a 38 year period from 1964 to 1992, is surveyed. Of these, 31 (7%) showed findings that indicated multilobular cirrhosis. There was a slight but not significant male predominance: 19 males against 12 females. Liver disease had its onset during childhood in most cases. The natural course of liver disease and of cirrhosis is protracted. All patients were routinely evaluated by way of: (i) clinical examination, (ii) biochemical studies and specifically estimation of transaminases and gamma glutamyltransferase, and (iii) liver imaging, ultrasonography, and computed tomography. The study aimed to detect early liver disease, that is multilobular cirrhosis and its complications, with a view to optimal introduction of treatment with ursodeoxycholic acid as this drug shows promise for preventing or stabilising the cirrhotic process. Effects of surgical treatment on portal hypertension are surveyed. These include portacaval shunting, partial splenectomy (considered the procedure of choice), liver transplant in the event of liver failure, or a triple transplant (liver, lungs, and heart) if necessary. One triple transplant was successfully performed in a boy of 10 years with a 2 year follow up.

Adolescent↗
PubMed1992

Allosteric activation by nucleotides of the inactive by phosphatase ornithine decarboxylase of Escherichia coli.

ODC was purified to homogeneity from E. coli K12 MG1655 strain transformed with a pBR322 plasmid carrying the ODC gene. This preparation was homogeneous as it was analyzed by SDS-polyacrylamide gel electrophoresis. From this preparation the amino-terminal sequence analysis was obtained. The native ODC of E. coli is activated by ATP, GTP, CTP and UTP at 10(-3) M concentration to around 170-300%. Our results indicate that the recombinant ODC is activated only by GTP and UTP at 10(-3) M 370% and 300%, respectively. When the recombinant ODC was incubated with calf intestine alkaline phosphatase, this inactive ODC can be reversibly activated allosterically only by GTP or UTP at a concentration of 10(-6) or 10(-5) M. That GTP or UTP can allosterically convert the inactive form of ODC to an active form suggests that these analogues may be the in vivo physiological regulators of ODC.

Alkaline Phosphatase↗
PubMed1991

Fatty infiltration: another restrictive cardiomyopathic pattern.

Restrictive cardiomyopathies have been shown to occur as result of infiltrative processes from a variety of sources. The current report describes an obese male, who was found to have hemodynamic evidence of a restrictive cardiac process. His pericardium was proven to be normal and an incisional biopsy obtained of the myocardium during coronary artery bypass surgery demonstrated histologic evidence of fatty infiltration of myocardium. Review of the restrictive and pathology literature is discussed and indicates that this is the first report to demonstrate the association between fatty infiltration and hemodynamic findings consistent with a restrictive cardiomyopathy.

Adipose Tissue↗
PubMed1988

Effect of coronary artery bypass grafting on left ventricular diastolic function.

Because left ventricular (LV) diastolic function is abnormal in patients with coronary artery disease (CAD), pulsed Doppler echocardiography was used to evaluate LV filling before and after coronary artery bypass grafting (CABG). Filling was evaluated by Doppler in 2 studies: (1) in a group of 41 unpaired patients (11 with angiographically normal coronary arteries, 14 with CAD but without CABG and 16 at 1 week after CABG) and (2) in a group of 12 patients with CAD before and 1 week after CABG. Doppler sampling at the level of the mitral anulus was analyzed for the deceleration half-time and for the ratio of peak late (A) to peak early (E) filling velocity, measures reflecting early ventricular filling and the relative contribution of atrial contraction to ventricular filling. In the first study the deceleration half-time was significantly prolonged in both CAD and CABG groups. The late to early peak transmitral velocity ratio, however, was significantly prolonged only in the nonrevascularized CAD patients. In the second group of CAD patients studied before and 1 week after surgical revascularization, both the late to early peak transmitral velocity ratio and the deceleration half-time showed significant postoperative improvement. Thus, patients with CAD showed impairment in early LV filling and a compensatory increase in the proportion of filling with active atrial contraction. Successful CABG appears to result in normalization of early filling and decreased reliance on active atrial transport.

Coronary Angiography↗