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Biomedical subjects

G Vanzetto

Publications and source records attributed to G Vanzetto.

At least 19 recordsLinked to original sources
PubMed2006

Assessment of non-reperfused and reperfused myocardial infarction using diffusible or deposited radiolabelled perfusion imaging agents.

PURPOSE: Incomplete microvascular reperfusion is often observed in patients undergoing thrombolytic therapy or angioplasty for acute myocardial infarction and has important prognostic implications. We compared the myocardial uptake of diffusible ((201)Tl) and deposited ((99m)TcN-NOET) perfusion imaging agents in the setting of experimental infarction. METHODS: Rats were subjected to permanent coronary occlusion (OCC, n=10) or to 45-min occlusion and reperfusion (REP, n=17). Seven days later, the tracers were co-injected and the animals were euthanised 15 min (all ten rats in the OCC group and 12 rats in the REP group) or 120 min (five rats from the REP group, euthanised at this time point to evaluate any redistribution of the tracers: REP-RED group) afterwards. Infarct size determination and (99m)TcN-NOET/(201)Tl ex vivo imaging were performed. Regional flow and tissue oedema were quantified using radioactive microspheres and (99m)Tc-DTPA, respectively. RESULTS: (99m)TcN-NOET and (201)Tl defect magnitudes were similar in OCC animals (0.11+/-0.01 vs 0.13+/-0.01). In REP animals, (201)Tl defect magnitude (0.25+/-0.02) was significantly lower than the magnitude of (99m)TcN-NOET and flow defects (0.14+/-0.03 and 0.17+/-0.01, respectively; p<0.05), despite the lack of (201)Tl redistribution (REP-RED animals). (99m)Tc-DTPA indicated the presence of oedema in the reperfused area. Blood distribution studies showed that, unlike (99m)TcN-NOET, (201)Tl plasma activity was mostly unbound to plasma proteins. CONCLUSION: (99m)TcN-NOET and (201)Tl delineated the non-viable area in chronic non-reperfused and reperfused myocardial infarction. The significantly decreased (201)Tl defect in reperfused infarction was likely due to partial diffusion of the tracer from the plasma into the oedema present in the infarcted area. Deposited perfusion tracers might be better suited than diffusible agents for the assessment of regional flow following reperfusion of myocardial infarction.

Animals↗
PubMed2006

[Cardiogenic shock due to acute myocarditis complicating leptospirosis].

A 48 year old man was admitted to the intensive care unit with septicaemic shock associated with febrile jaundice and anuric renal failure. Within hours, he developed cardiogenic shock with multi-organ failure due to an acute myocarditis refractory to catecholamines and requiring intra-aortic balloon pumping. The diagnosis was an ictero-haemorrhagic leptospirosis, the outcome of which was finally favourable. Myocarditis is an underestimated complication of leptospirosis because it is often symptomless. The main signs are arrhythmias, conduction defects and ST-T wave abnormalities which have little clinical expression. The disease may progress and is sometimes fatal. Leptospirosis myocarditis should therefore be carefully considered because of its potential severity and its reversibility with appropriate antibiotic therapy and also the necessity of initial management in a specific infrastructure.

Humans↗
PubMed2006

[Analysis of the accuracy of a coronary syndrome register].

Registers of the management of infarction can complement information obtained from randomised trials evaluating the methods and practice of treatment. In order to do this, the quality of the registers must be assured, and in particular the accuracy of the recorded cases. The objective of this study was to evaluate the accuracy of a register for the in-hospital and pre-hospital management of acute coronary syndromes with ST segment elevation of less than 12 hours' duration. Using a capture-recapture method, the study compared cases in the register with eligible cases present in the hospital and emergency ambulance service databases at two establishments, giving a recruitment rate of 61%. The rate of accuracy was estimated at 84% (95% CI [82 ; 86]). The independent factors associated with failure of notification were female sex (ORa=6.65 [2.04-21.69]), presentation at nights, weekends or bank holidays (ORa=4.13 [1.33-12.85]), direct admission to hospital without passing by the emergency ambulance service (ORa=2.85 [1.03-7.69]), primary angioplasty (ORa=6.18 [1.60-23.79]) and the absence of reperfusion (ORa=40.38 [6.21-262.40]). With more than 80% accuracy, the results produced by the register are robust. The selection bias linked to the under-representation of certain subgroups, while real, has only a marginal impact on estimates derived from the register. Factors associated with failure of notification should be taken into account when operating such a register.

Angina, Unstable↗
PubMed2005

[Epidemiology of athrotherombotic lower limb arterial disease].

Chronic occlusive arterial disease of the lower limbs is a common presentation of atherothrombotic disease. This systematic review of the literature analyses the natural history of this condition and the prevalence of asymptomatic lesions of other arterial localisations requiring specific treatment. The Medline database was researched and completed by a bibliography of the principal articles selected, Internet sites and their publication reviews and also the Cochrane database. The incidence of systemic complications has been assessed in many good quality epidemiological study. It increases with the severity of lower limb arterial disease, but in asymptomatic patients defined by a pathological systolic pressure index (< 0.90) the cardiovascular mortality is already 2% per year, the incidence of myocardial infarction 3% per year and that of cerebrovascular accidents 1 to 2% per year. The prevalence of asymptomatic lesions in other arterial sites is less well documented, the evaluations varying according to the population studied and criteria of significant lesions: 21 to 69% for coronary artery disease, 12 to 59% for carotid artery stenosis, 14 to 40% for renal artery stenosis and 6 to 14% for abdominal aortic aneurysms. Despite the uncertainty of these estimations, the prevalence of asymptomatic atherothrombotic lesions is high in all arterial networks and justifies the setting up of studies to assess the clinical benefits of their systematic diagnostic investigations.

Arteriosclerosis↗
PubMed2004

[Strategy of investigation of coronary artery disease in diabetes: from screening to suspicion of acute coronary syndromes].

Coronary artery disease is a common and serious condition in diabetes and the prognosis of the diabetic without a history of cardiovascular disease is either the same or nearly as serious as that of a non-diabetic patient with a history of coronary disease. This is particularly true in women. The prognosis is even worse in the presence of silent myocardial ischaemia. Conversely, anti-ischaemic and anti-thrombotic therapy and myocardial revascularisation of most severely affected patients are effective. This justifies the recent recommendations (as those of the working group of the French Society of Cardiology and the ALFEDIAM) for the diagnosis of coronary artery disease in diabetes, even in asymptomatic patients. This is a two stage process: --First, the identification of patients who should be screened for ischaemia, diabetics with a priori an intermediate or high risk of the presence of CAD, with respect to the presence of markers easily identified on initial examination, like the presence of clinical macroangiopathy (femoral, carotid), of renal disease or ECG changes or the presence of several classical risk factors; --The second stage is the demonstration of myocardial ischaemia in patients identified to be at risk. This article reviews the advantages and limits of the tests available: ECG stress test, myocardial perfusion imaging on effort or under dipyridamole, stress echocardiography. Coronary angiography in asymptomatic patients is only recommended in the presence of significant ischaemia or with a poor prognosis (affecting over 20% of the myocardium or several myocardial territories). This should precede a myocardial revascularisation procedure. The prescription of coronary angiography may be more direct in some symptomatic patients.

Acute Disease↗
PubMed2003

Severity assessment of acute pulmonary embolism: evaluation using helical CT.

The objective was to evaluate the helical CT (HCT) criteria that could indicate severe pulmonary embolism (PE). In a retrospective study, 81 patients (mean age 62 years) with clinical suspicion of PE explored by HCT were studied. The patients were separated into three different groups according to clinical severity and treatment decisions: group SPE included patients with severe PE based on clinical data who were treated by fibrinolysis or embolectomy ( n=20); group NSPE included patients with non-severe PE who received heparin ( n=30); and group WPE included patients without PE ( n=31). For each patient we calculated a vascular obstruction index based on the site of obstruction and the degree of occlusion in the pulmonary artery. We noted the HCT signs, i.e., cardiac and pulmonary artery dimensions, that could indicate acute cor pulmonale. According to multivariate analysis, factors significantly correlated with the severity of PE were: the vascular obstruction index (group SPE: 54%; group NSPE: 24%; p<0.001); the maximum minor axis of the left ventricle (group SPE: 30.2 mm; group NSPE: 40.4 mm; p<0.001); the diameter of the central pulmonary artery (group SPE: 32.4 mm; group NSPE: 28.3 mm; p<0.001); the maximum minor axis of the right ventricle (group SPE: 47.5 mm; group NSPE: 42.7 mm; p=0.029); the right ventricle/left ventricle minor axis ratio (group SPE: 1.63; group NSPE: 1.09; p<0.0001). Our data suggest that hemodynamic severity of PE can be assessed on HCT scans by measuring four main criteria: the vascular obstruction index; the minimum diameter of the left ventricle; the RV:LV ratio; and the diameter of the central pulmonary artery.

Case-Control Studies↗
PubMed2000

99mTc-N-NOET myocardial uptake reflects myocardial blood flow and not viability in dogs with reperfused acute myocardial infarction.

BACKGROUND: N-Ethoxy-N-ethyl-dithiocarbamato-nitrido-(99m)Tc ((99m)Tc-N-NOET) is a new neutral lipophilic (99m)Tc-labeled myocardial perfusion agent with a high first-pass extraction fraction and delayed redistribution kinetics after transient ischemia comparable to what is observed with (201)Tl. It is unknown whether the uptake of this tracer reflects myocardial viability or just reperfusion flow in the setting of a reperfused myocardial infarction. METHODS AND RESULTS: In 13 anesthetized open-chest dogs, the left anterior descending coronary artery was occluded for 180 minutes, followed by 180 minutes of reperfusion. (201)Tl and (99m)Tc-N-NOET were injected after either 60 (group 1, n=9) or 175 (group 2, n=4) minutes of reperfusion. Myocardial blood flow was measured by radioactive microspheres, and (201)Tl and (99m)Tc-N-NOET tissue activities were determined by gamma-well counting. Normalized myocardial blood flow in the central infarct zone fell from 0.80+/-0. 03 (SEM) and 0.89+/-0.01 at baseline to 0.18+/-0.04 and 0.13+/-0.02 during the occlusion in groups 1 and 2, respectively. Normalized (201)Tl activity in these segments was 0.39+/-0.04 and 0.43+/-0.04 and reflected myocardial viability rather than reperfusion flow (P<0. 001). Normalized (99m)Tc-N-NOET activity in the same segments was 0. 84+/-0.08 and 0.64+/-0.03, respectively (P<0.01 versus (201)Tl; P=NS versus reperfusion flow) and more accurately reflected reperfusion flow (0.99+/-0.17 and 0.70+/-0.04) than residual viability. CONCLUSIONS: The myocardial uptake of (99m)Tc-N-NOET reflects reperfusion myocardial blood flow and not viability in a canine model of reperfused acute myocardial infarction. The clinical use of early (99m)Tc-N-NOET imaging to assess the success of coronary reperfusion in patients with acute myocardial infarction should be investigated.

Animals↗
PubMed2000

Biodistribution, dosimetry, and safety of myocardial perfusion imaging agent 99mTcN-NOET in healthy volunteers.

UNLABELLED: 99mTcN-NOET (bis[N-ethoxy,N-ethyl]dithiocarbamato nitrido technetium (V)) has been proposed for myocardial perfusion imaging. Biodistribution, safety, and dosimetry were studied in 10 healthy volunteers (5 at rest and 5 during exercise). METHODS: Biodistribution was studied by acquiring dynamic images up to 60 min after injection and whole-body images up to 24 h after injection. The MIRDOSE3 analysis program was used for radiation dosimetry calculations. RESULTS: Safety parameters measured to 48 h after injection revealed no clinically significant changes. Cardiac uptake of 99mTcN-NOET was high (2.9%-3%), with biologic half-life of 210-257 min on average. Lung uptake of 99mTcN-NOET was higher (10%-20%) but, on average, biologic half-life was shorter (1-77 min). Clearance from the blood was rapid (5% by 5 min). Radiation dosimetry calculations indicated an effective absorbed dose of 5.11 x 10(-3) mSv/MBq at rest and 5.38 x 10(-3) mSv/MBq after exercise. CONCLUSION: 99mTcN-NOET exhibits high cardiac uptake and an estimated effective absorbed dose comparable with that of the other 99mTc-labeled compounds used in myocardial perfusion imaging.

Adult↗
PubMed2000

[Which coronary tests to use in asymptomatic diabetics?].

Coronary artery disease is a common, serious and insidious complication of diabetes. Myocardial ischaemia is often silent. All diabetics do not have the same coronary risk and, therefore, it is important to determine which investigations to perform and which patients. This strategy is justified because it allows identification of these cases which require a medical or an invasive (angioplasty, surgical revascularisation) approach, as these interventions may improve the prognosis. The first stage is clinical (investigation of cardiovascular risk factors). When more than two risk factors are found, further investigations are justified. Exercise stress testing provide reassuring diagnostic and prognostic data when maximal and negative. When sub-maximal, impossible or significantly ischaemic, a second investigation is useful. Holter ECG recording with analysis of ST variation lacks sensitivity and, above all, specificity. The diagnostic value of perfusion myocardial scintigraphy in the diabetic is not as good as that observed in the general population, but its prognostic value remains good. Ischaemia involving over 20% of the myocardium justifies therapeutic investigation. Stress echocardiography has been validated in the diagnosis and prognosis of coronary artery disease and its sensitivity and specificity are probably the same as those of scintigraphy. The authors conclude that the asymptomatic diabetic requires clinical and staged paraclinical investigation to assess prognosis and, depending on the results, the adoption of a beneficial therapeutic strategy.

Cardiovascular Agents↗
PubMed1999

Myocardial uptake of (99m)Tc-N-NOET and (201)Tl during dobutamine infusion. Comparison with adenosine stress.

BACKGROUND: The myocardial uptake of (99m)Tc-sestamibi is attenuated by dobutamine stress, resulting in underestimation of ischemia. N-Ethyl-N-ethoxy-dithiocarbamato-N-(99m)Tc ((99m)Tc-N-NOET) is a new (99m)Tc-labeled perfusion agent that is highly extracted by the myocardium by a mechanism different from that defined for (99m)Tc-sestamibi. We therefore hypothesized that (99m)Tc-N-NOET uptake would not be attenuated by dobutamine and that (99m)Tc-N-NOET uptake would be comparable to (201)Tl uptake during dobutamine stress. METHODS AND RESULTS: In 28 open-chest dogs, after placement of a stenosis in the left anterior descending coronary artery that reduced flow reserve by >50%, adenosine (300 microgram. kg(-1). min(-1); n=15) or dobutamine (2.5 to 30 microgram. kg(-1). min(-1); n=13) was infused. During adenosine stress, the stenotic-to-normal activity ratio for (99m)Tc-N-NOET was 0.55+/-0.05. The stenotic-to-normal flow ratio was 0.33+/-0.04 at the time of (99m)Tc-N-NOET injection. During dobutamine stress, the stenotic-to-normal (99m)Tc-N-NOET activity ratio was 0.63+/-0.04, comparable to the (201)Tl activity ratio of 0.59+/-0.04. The stenotic-to-normal flow ratio was 0.47+/-0.04 at the time of (99m)Tc-N-NOET and (201)Tl injection. The relationship between (99m)Tc-N-NOET uptake and blood flow was comparable for adenosine and dobutamine stress, with no evidence of attenuation of (99m)Tc-N-NOET extraction by dobutamine. Conclusions-In the presence of coronary stenoses that reduced regional flow reserve, the myocardial uptake of (99m)Tc-N-NOET and (201)Tl are closely proportional to blood flow during both adenosine and dobutamine stress, suggesting that the adverse effect of dobutamine on (99m)Tc-sestamibi uptake is a tracer-specific phenomenon rather than a generalized effect. The clinical implication of this finding is that (99m)Tc-N-NOET might be preferable to (99m)Tc-sestamibi when used with dobutamine stress for detection of coronary stenoses.

Adenosine↗
PubMed1999

Long-term additive prognostic value of thallium-201 myocardial perfusion imaging over clinical and exercise stress test in low to intermediate risk patients : study in 1137 patients with 6-year follow-up.

BACKGROUND: The exercise treadmill test (ETT) and Tl201 single proton emission computed tomography (SPECT) are of short- to medium-term prognostic value in coronary heart disease. We assessed the long-term prognostic value of these tests in a large population of patients with low- to intermediate risk of cardiac events. METHODS AND RESULTS: One thousand one hundred thirty-seven patients (857 men, age 55+/-9 years) referred for typical (62.1%) or atypical (22.4%) chest pain, or suspected silent ischemia (15.5%), were followed up for 72+/-18 months. Overall mortality was higher after strongly positive (ST depression >2 mm, or >1 mm for a workload </=75 W) (2. 36%/y) or nondiagnostic ETT (1.63%/y) than after normal (0.85%/y) or positive ETT (1.37%/y) (P=0.002), and after abnormal SPECT than after normal SPECT (1.60%/y versus 0.68%/y, P=0.001). The major cardiac event rate (cardiac death or myocardial infarction [MI]) was 0.88%, 1.59%, 2.10%, and 2.13%/y after negative, positive, strongly positive, and nondiagnostic ETT, respectively (P=0.003), and 0.56%, 1.43%, and 2.05%/y in patients with 0, 1 to 2, and >/=3 abnormal segments on SPECT, respectively (P<0.002). An abnormal SPECT was predictive of MI (P<0.001), whereas ETT was not. In multivariate analysis, SPECT was of incremental prognostic value over clinical and ETT data for predicting overall mortality and major cardiac events. CONCLUSIONS: The incremental predictive value of SPECT is maintained over 6 years and is particularly relevant after positive, strongly positive, and nondiagnostic ETT.

Adult↗
PubMed1999

Myocardial infarction and Turner's syndrome.

This paper reports the case of a patient with Turner's syndrome, who developed a myocardial infarction at the age of 36. Turner's syndrome, associated with gonadal insufficiency, increases atherosclerotic cardiovascular risks that must be assessed during the patient's follow-up.

Adult↗