Evaluation of regional myocardial systolic and diastolic function using ECG-gated Sestamibi scintigraphy Preliminary results in patients with and without coronary artery disease

Sestamibi allows ECG-gated acquisition and similarly to radionuclide angiography a time-activity curve from a defined myocardial region can be derived and analysed. Diastolic (peak relaxation velocity) and systolic (per cent thickening) functional parameters from Sestamibi ECG-gated acquisition were obtained; this data were compared in 10 patients with radionuclide angiographic data (peak filling rate and ejection fraction, respectively). A high correlation was found between peak relaxation velocity and peak filling rate (r = 0.792), while no significant correlation was found between thickening and ejection fraction (r=0.577). Sestamibi parameters were calculated in 15 patients with known or suspected coronary artery disease and compared with those obtained in 10 normal subjects. In regions supplied by stenotic vessels the average values of peak relaxation velocity and thickening were significantly lower than those obtained in control subjects in the corresponding vascular territory. The average regional values of the diastolic parameter were significantly lower than the corresponding normal range also in regions with preserved systolic function, i.e. with thickening values within 1SD from the mean value of normals.In conclusion, from the ECG-gated acquisition of Sestamibi regional diastolic and systolic functional parameter may be derived; this completes the spectrum of information that can be obtained by a single injection of tracer.Abbreviations EDc end-diastolic counts - EDV end-diastolic volume - EF% ejection fraction - ESc end-systolic counts - ESV end-systolic volume - PFR peak filling rate - PRV peak relaxation velocity - TH% percent thickening     

Right ventricular dysfunction in demand-induced ischemia in patients with isolated right coronary artery disease: a radioisotope study

In ischemic heart disease, the left ventricle has been considered the main target of an imbalance between myocardial oxygen supply and demand. Accordingly, the approach to ischemia has been directed at the evaluation of the left ventricle. The aim of this study was to assess the relative involvement of the left and right ventricle in patients with isolated right coronary artery stenosis. We studied 20 patients with a clinical history of effort angina (15 male, 5 female, mean age 54.1 +/- 6.2) using radionuclide angiography and atrial pacing. Findings were compared with those of 6 normal subjects that were paced at the maximal heart rate of 150 beats/min. Atrial pacing was interrupted because of diagnostic ST segment depression in 8 patients, Wenckebach type atrioventricular block in 1, chest pain without electrocardiographic changes in 4 and the achievement of the maximal prefixed heart rate of 150 beats/minute in 7. With respect to control conditions, during atrial pacing right ventricular ejection fraction declined from 46.8 +/- 6.8% to 37.4 +/- 8.1% (p less than 0.001), while no significant change was observed in left ventricular ejection fraction values (55.2 +/- 4.5% and 51.1 +/- 10.2% respectively). During atrial pacing, left ventricular peak filling rate increased from 1.77 +/- 0.53 to 4.71 +/- 1.8 end-diastolic volumes/second (p less than 0.0001). Qualitative analysis of regional wall motion showed a right ventricular dysfunction in 19/20 patients; this was prevalent in 9 and involving also the left ventricle in 10; an isolated impairment of the left ventricle was observed in 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)     

Minimally invasive treatment of synchronous colorectal tumours

In patients with colorectal cancers synchronous neoplastic lesions are an increasingly frequent finding at preoperative staging; 3% of the cases are other cancers while 33-35% of the synchronous lesions are villous adenomas. The treatment of most colorectal adenomas can be performed by endoscopic poplypectomy. In 5% of cases there are synchronous colorectal lesions also requiring surgical treatment. From January 1995 to June 2007 we treated 5 patients with rectal lesions by transanal endoscopic microsurgery (TEM) together with a laparoscopic colectomy for the presence of synchronous lesions at the "Clinica Chirurgica Generale e d'Urgenza" of the University of Perugia,. Surgical timing involved performing a sequential exeresis characterised by a cancer resection, followed by resection of the voluminous adenoma: TEM for rectal cancer followed by a laparoscopic right hemicolectomy with an extracorporeal anastomosis for a voluminous villous adenoma (1 patient) and laparoscopic right hemicolectomy with an extracorporeal anastomosis for cancer followed by TEM for a voluminous villous adenoma (2 patients). One patient with left colon cancer associated with a voluminous villous rectal adenoma first underwent TEM for the rectal adenoma and then a left laparoscopic hemicolectomy with an extracorporeal anastomosis in order to ease the transit of the circular mechanical stapler. Another patient with rectal and right colon adenomas first underwent TEM for a voluminous rectal sessile adenoma and later a right hemicolectomy. The use of this minimally invasive approach allowed rectum preservation and less invasive surgery.     

Coronary microcirculatory vasoconstriction during ischemia in patients with unstable angina

OBJECTIVE: To verify the behavior of coronary microvascular tone during spontaneous ischemia in patients with unstable angina (UA). BACKGROUND: In UA, the pathogenetic role of vasoconstriction is classically confined at the stenotic coronary segment. However, microcirculatory vasoconstriction has been also suggested by previous experimental and clinical studies. METHODS: The study included 10 patients with UA (recent worsening of anginal threshold and appearance of angina at rest) and single-vessel CAD. Blood flow velocity was monitored by a Doppler catheter in the diseased artery. Transstenotic pressure gradient was monitored by aortic and distal coronary pressure monitoring. Stenosis resistance was calculated as the ratio between pressure gradient and blood flow, microvascular resistance as the ratio between distal pressure and blood flow. Measurements were obtained at baseline, following intracoronary adenosine (2 mg) and during transient ischemia. Aortic and distal coronary pressures were also measured during balloon coronary occlusion. RESULTS: Adenosine did not affect stenosis resistance, while it decreased (p < 0.05) microvascular resistance to 52 +/- 22% of baseline. Angina and ischemic ST segment shift were associated with transient angiographic coronary occlusion in 7 of 10 patients; however, in no case was ischemia associated with interruption of flow. Despite markedly different flow values, distal coronary pressure was similar during adenosine and during spontaneous ischemia (48 +/- 15 vs. 46 +/- 20 mm Hg, respectively, NS). During ischemia, a marked increase in the resistance of both coronary stenosis and coronary microcirculation was observed (to 1,233% +/- 1,298% and 671% +/- 652% of baseline, respectively, p < 0.05). Distal coronary pressure was markedly reduced during balloon coronary occlusion (14 +/- 7 mm Hg, p < 0.05 vs. both adenosine and ischemia), suggesting the absence of significant collateral circulation. CONCLUSIONS: In patients with UA, transient myocardial ischemia is associated with vasoconstriction of both stenotic arterial segment and downstream microcirculation.     

Catecholamine production and tyrosine hydroxylase expression in peripheral blood mononuclear cells from multiple sclerosis patients: effect of cell stimulation and possible relevance for activation-induced apoptosis

Sympathoadrenergic mechanisms may play a role in multiple sclerosis (MS). We examined catecholamine (CA) levels and production and tyrosine hydroxylase (TH) expression in peripheral blood mononuclear cells (PBMCs) from MS patients, and the correlation between CA production and apoptosis in PBMCs. PBMCs from MS patients had increased norepinephrine (NE) levels. However, phytohaemagglutinin (PHA)-stimulated PBMCs from MS patients with active disease synthesized less dopamine (DA) than cells from both healthy controls and patients with inactive disease. PBMCs from patients with inactive disease showed lower expression of TH. Pharmacological inhibition of TH in cultured PBMCs stimulated with PHA reduced the percentage of apoptotic cells. Since a failure of activation-induced apoptosis in immune cells may be involved in MS, it is suggested that altered CA production by PBMCs may be implicated in such dysregulation.     

Myocardial metabolic and receptor imaging in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDC) is a distinct disease of the myocardium, of unknown etiology. The disease can occur acutely, or evolve in a subacute fashion. IDC is often associated with a substantial impairment of ventricular function, which may recover over time. Although spontaneous recovery of LV function occurs in 20%-45% of newly diagnosed patients, the majority of patients do not do well. IDC has an average 5-year mortality of 20%. Abnormalities of energetics, perfusion, and adrenergic control of the myocardium are markers of the status of LV dysfunction. As the heart fails, changes occur in the production and catabolism of high-energy substrates, the efficiency of mitochondrial oxidative processes, the distribution of resting perfusion and coronary vasodilating capacity and the adrenergic receptor density and function. This article reviews the information provided by metabolic and receptor imaging in patients with IDC, and the role the data may play in patient management.     

Cardiac phantom measurement validating the methodology for a cardiac multi-centre trial with positron emission tomography

In an ongoing international multi-centre trial, positron emission tomography (PET) is being used to evaluate the effect of a new P-selectin antagonist on the infarct size in patients with acute myocardial infarction, treated with thrombolysis. Although it is possible to correct for site-dependent factors, it is desirable to reduce these factors to a minimum. Therefore, acquisition and reconstruction protocols have been defined that can be closely followed by all participating centres. The resulting reconstructed images are transferred to the core centre for central processing with semi-automatic software. This paper reports on the multi-centre phantom experiment that was carried out to assess the inter-centre reproducibility of defect size determination with this protocol. Also, the spatial resolution of the short axis slices was examined. In addition, the analysis procedure was applied to normal PET studies to evaluate the specificity of perfusion defect detection. The transmural cold defect in the phantom occupied 14.8% of the left ventricular area. The automated analysis was applied to the phantom measurements from the 14 participating PET cameras. It yielded an accurate estimate of 15.1% with a standard deviation of 0.6%, indicating excellent reproducibility. The spatial resolution in the short axis slices was similar for all PET systems: 9.6+/-0.8 mm. The same procedure produced a defect size of zero in the studies of normal volunteers. This study indicates that cardiac studies from multiple PET systems can be pooled for statistical analysis.