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Biomedical subjects

Leonarda Galiuto

Publications and source records attributed to Leonarda Galiuto.

8 recordsLinked to original sources
PubMed2006

Reversible microvascular dysfunction coupled with persistent myocardial dysfunction: implications for post-infarct left ventricular remodelling.

BACKGROUND: Recent studies have shown that microvascular dysfunction after myocardial infarction is a dynamic phenomenon. AIMS: To evaluate the implications of dynamic changes in microvascular dysfunction on contractile recovery and left ventricular remodelling, and to identify the ideal timing of assessment of such microvascular dysfunction. METHODS AND RESULTS: In 39 patients with a first myocardial infarction who underwent successful percutaneous coronary intervention, microvascular dysfunction was studied by myocardial contrast echocardiography (MCE) at 24 h, 1 week and 3 months after the procedure. Real-time MCE was performed by contrast pulse sequencing and intravenous Sonovue. 14 patients exhibited left ventricular remodelling at 3 months (>20% increase in left ventricular end-diastolic volume, group B), whereas 25 did not (group A). Microvascular dysfunction was similar in the two groups at 24 h and improved in group A only, being significantly better than that of group B at 1 week (p<0.05) and 3 months (p<0.005). Improvement in microvascular dysfunction was not associated with improvement in wall motion in the same segments. With multivariate analysis including all echocardiographic variables, microvascular dysfunction at 1 week was found to be the only independent predictor of left ventricular remodelling (p<0.01). With a cut-off value of 1.4, 1-week microvascular dysfunction predicts left ventricular remodelling with sensitivity and specificity of 73%. CONCLUSIONS: Improvement in microvascular dysfunction occurs early after myocardial infarction, although it is not associated with a parallel improvement in wall motion but is beneficial in preventing left ventricular remodelling. Accordingly, 1-week microvascular dysfunction is a powerful and independent predictor of left ventricular remodelling.

Contrast Media↗
PubMed2006

Thrombus aspiration reduces microvascular obstruction after primary coronary intervention: a myocardial contrast echocardiography substudy of the REMEDIA Trial.

OBJECTIVES: The aim of this study was to clarify the role of microembolization in the genesis of microvascular obstruction (MO) after percutaneous coronary intervention (PCI). BACKGROUND: Fifty consecutive patients entered the myocardial contrast echocardiography (MCE) substudy of the REMEDIA (Randomized Evaluation of the Effect of Mechanical Reduction of Distal Embolization by Thrombus Aspiration in Primary and Rescue Angioplasty) trial, which defined the role of a new thrombus-aspirating device in preventing distal microembolization after PCI. METHODS: A total of 25 patients were randomized to be pretreated with thrombus aspiration before PCI of the culprit lesion and 25 received standard PCI. At 24 h, 1 week, and 6 months after PCI, MCE was performed by Sonovue, and real-time imaging was performed by contrast pulse sequencing technology. Regional wall motion score index (WMSI), contrast score index (CSI), endocardial length of wall motion abnormality (WML) and contrast defect (CDL), end-diastolic and end-systolic left ventricular (LV) volumes, and ejection fraction were calculated. RESULTS: At each time point, in patients treated with a thrombus-aspiration filter device, WMSI, CSI, WML, and CDL were significantly lower and ejection fraction higher (p < 0.05 vs. control patients), whereas LV volumes were slightly but not significantly smaller compared with control patients. In the overall study population, the extent of MO significantly correlated with temporal changes in LV volumes. CONCLUSIONS: Thrombus aspiration used at the time of PCI significantly reduces the extent of MO and myocardial dysfunction, although it does not have a significant favorable effect in preventing LV remodeling. Thus, the beneficial effect of thrombus aspiration occurs at the microvascular level, but additional mechanisms may play a role in influencing the final extent of MO, which strictly correlates with post-infarct LV remodeling.

Aged↗
PubMed2006

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT.

BACKGROUND: Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique. METHODS: Fourteen consecutive patients underwent MCE, MRI and 99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or "patchy" perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal. RESULTS: At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT. CONCLUSION: MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.

Contrast Media↗
PubMed2006

No-reflow: a heterogeneous clinical phenomenon with multiple therapeutic strategies.

Previously defined as the failure to achieve uniform intramyocardial reperfusion after prolonged but reversible coronary occlusion, only recently has no-reflow phenomenon been characterized as a heterogeneous clinical condition. In fact, in about half of post-infarct patients that show no-reflow after 24 hours from coronary recanalization by either thrombolysis or PTCA, no-reflow phenomenon is spontaneously reversible. Reversible no-reflow is associated with favorable left ventricular remodeling even in the absence of significant improvement in regional contractile function. Thus, it may be a clinical marker of yet unknown mechanisms, which may favorably affect myocardial response to necrosis. Based on the pathogenesis and on the time-course of no-reflow, the phenomenon may be associated with lack of patency or with loss of anatomic integrity of microvessels, with the former being potentially reversible while the latter associated with definitive tissue damage. As a consequence, possible therapeutic strategies of no-reflow have to be designed according to not only the main target [microvessel patency or integrity], but also taking into account the timing of development of the damage. This "mini review" is focused on recent advances on the pathogenesis and clinical presentation on no-reflow. These data will give the opportunity to formulate novel interpretation and classification of the phenomenon and consequently, to propose adequate therapeutic strategies.

Adenosine↗
PubMed2005

Myocardial infarction in isolated ventricular non-compaction: contrast echo and MRI.

We describe the case of an occasional discovery of isolated ventricular non-compaction in an adult recovered for an acute myocardial infarction, in which only the echocardiogram revealed an isolated ventricular non-compaction, confirmed by MRI: an unusual association between coronary artery disease and isolated ventricular non-compaction.

Electrocardiography↗
PubMed2005

Mobilization of bone marrow-derived stem cells after myocardial infarction and left ventricular function.

AIMS: Recent data suggest that the administration of bone marrow-derived stem cells (BMSC) might improve myocardial perfusion and left ventricular (LV) function after acute myocardial infarction (AMI). The aim of this study was to assess spontaneous mobilization of BMSC expressing the haematopoietic and endothelial progenitor cell-associated antigen CD34+ after AMI and its relation to post-infarction remodelling. METHODS AND RESULTS: Peripheral blood concentration of CD34+ BMSC was measured by flow cytometry in 54 patients with AMI, 26 patients with chronic stable angina (CSA), and 43 normal healthy subjects. In patients with AMI, LV function was measured by 2D-echocardiography. Eighteen AMI patients were reassessed at 1 year. BMSC concentration was higher in patients with AMI (mean peak value: 7.04+/-6.27 cells/microL), than in patients with CSA (3.80+/-2.12 cells/microL, P=0.036) and in healthy controls (1.87+/-1.52 cells/microL, P<0.001). At multivariable analysis statin use (P<0.001), primary percutaneous intervention (P=0.048) and anterior AMI (P=0.05) were the only independent predictors of increased BMSC mobilization after AMI. In the 28 patients without subsequent acute coronary events reassessed at 1 year follow-up, CD34+ cell concentration was an independent predictor of global and regional improvement of LV function (r=0.52, P=0.004 and r=-0.41, P=0.03, respectively). CONCLUSION: AMI is followed by enhanced spontaneous mobilization of BMSC, in particular, in patients on statin therapy and following a primary percutaneous intervention. More importantly persistent spontaneous mobilization of BMSC might contribute to determine a more favourable post-AMI remodelling.

Antigens, CD34↗
PubMed2002

Assessment of coronary stenoses of graded severity by myocardial contrast echocardiography.

BACKGROUND: Myocardial contrast echocardiography (MCE) has potential value in the assessment and quantitation of myocardial perfusion defects. However, the severity of stenosis detectable by MCE and its diagnostic accuracy remain undefined. Thus, we produced coronary stenoses of variable severity and quantified their effect on MCE. METHODS AND RESULTS: Three grades of left anterior descending (LAD) obstructions were produced in 7 open-chest swine. The stenoses were nonflow-limiting at rest, but decreased coronary hyperemia by 31.3% +/- 4.7%, 69.9% +/- 5.3% and 98.9% +/- 1.1%, respectively. Regional myocardial blood flow (RBF) was measured with fluorescent microspheres and was expressed as the ratio of LAD and control (LCx) beds. MCE was performed with 0.3 mg/kg intravenous AF0150 during ECG-gated harmonic imaging in short-axis view. Background-subtracted peak intensity (PI) was expressed as the ratio of LAD/LCx beds. Both RBF and PI ratios progressively decreased with increasing grades of stenosis. MCE showed a significant correlation with RBF (r = 0.74; P <.0001). Ratios of both PI and RBF differed significantly from baseline when coronary hyperemia was reduced more than 50%. An LAD/LCx ratio less than 0.6 by MCE yielded 61% and 83% sensitivity and 85% and 76% specificity with stenosis that reduced coronary hyperemia more than 50% and more than 75%, respectively. CONCLUSION: MCE with intravenous AF0150 during vasodilation correctly depicted the progressive reduction of flow ratios produced by graded coronary stenoses. A significant reduction of PI ratio was observed with stenosis causing more than 50% reduction of coronary hyperemia. An MCE ratio in stenosed/control beds could be selected, which exhibited good sensitivity and specificity in the identification of coronary stenosis.

Animals↗