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F Vigorito

Publications and source records attributed to F Vigorito.

14 recordsLinked to original sources
PubMed2005

Association between intraventricular myocardial systolic dyssynchrony and ventricular arrhythmias in patients with hypertrophic cardiomyopathy.

BACKGROUND: The distribution and magnitude of left ventricular (LV) hypertrophy are not uniform in patients with hypertrophic cardiomyopathy (HCM), which results in regional heterogeneity of LV systolic and diastolic function. The aim of the study was to evaluate LV regional systolic asynchrony in patients with HCM by pulsed Doppler myocardial imaging (DMI). METHODS: We studied 35 HCM patients and 45 age- and sex-matched controls. By the use of DMI, the following five different basal myocardial segments were measured: systolic peak velocity (Sm); early- and late-diastolic peak velocities; pre-contraction time (Q-Sm) (from the beginning of Q-wave of ECG to the onset of Sm); intraventricular systolic delay (IntraV-Del) (difference of Q-Sm in different LV myocardial segments); interventricular delay (InterV-Del) (difference of Q-Sm between the most delayed LV segment and right ventricular lateral wall). RESULTS: DMI analysis showed in HCM lower myocardial systolic and early-diastolic peak velocities of all the analyzed segments. As for time intervals, controls showed homogeneous systolic activation of the ventricular walls. Conversely, HCM group, despite the absence of intraventricular conduction defects by surface ECG, showed significant both Inter- and IntraV-Del (P < 0.0001). Linear regression models pointed out independent positive associations of IntraV-Del with LV outflow gradient and septal wall thickness in HCM (P < 0.001). An IntraV-Del >30 msec well differentiated controls and HCM. In addition, an IntraV-Del > 45 msec (ROC curve) identified a subgroup of HCM patients with nonsustained ventricular tachycardia during Holter monitoring (90.9% sensitivity and 95.8% specificity). CONCLUSIONS: The impairment of intrarventricular systolic synchronicity is strongly related to increased septal thickness and LV outflow-tract gradient in HCM. DMI analysis may be able to select subgroups of HCM patients at an increased risk of ventricular tachyarrhythmias.

Adult↗
PubMed2003

Long-lasting antithrombotic effects of a single dose of human recombinant, active site-blocked factor VII: insights into possible mechanism(s) of action.

Tissue factor (TF) is important in initiating intravascular thrombosis. We demonstrated that active-site blocked factor VII (FVIIai) inhibits intravascular thrombosis for at least 6 h following a single injection, despite FVIIai plasma half-life was approximately 45 min. The aims of the present study were: (a) to determine the duration of the antithrombotic effects of a single injection of FVIIai; and (b) to assess whether FVIIai prolonged effects can be explained by a slow dissociation rate from TF in the arterial wall. Cyclic flow variations (CFVs), obtained in stenotic rabbit carotid arteries with endothelial injury, were abolished by either FVIIai (100 micro g kg-1 min-1 for 10 min) or hirudin (1 mg kg-1). After CFVs were abolished, carotid blood flow velocity was recorded continuously for 24 h. CFVs restored in all hirudin-treated animals after 2.1 +/- 0.3 h, while they restored in only four of nine FVIIai-treated rabbits in 10.1 +/- 2.2 h. Five animals in this group did not show restoration of CFVs up to 24 h. Immunohistochemistry revealed that FVIIai was still bound to the arterial wall 24 h following its administration, despite at this time FVIIai plasma levels were undetectable. Prothrombin time and partial thromboplastin time did not change significantly. FVIIai exerts potent, long-lasting antithrombotic effects without affecting systemic hemostatic parameters; a possible mechanism is a slow dissociation rate of FVIIai from TF. These proprieties make FVIIai particularly attractive as an antithrombotic intervention.

Animals↗
PubMed2001

Expression of exogenous tissue factor pathway inhibitor in vivo suppresses thrombus formation in injured rabbit carotid arteries.

OBJECTIVES: The aim of the present study was to test the hypothesis that retrovirus-mediated in vivo tissue factor pathway inhibitor (TFPI) gene transfer to the arterial wall would efficiently inhibit thrombosis without causing significant changes in systemic hemostatic variables. BACKGROUND: Acute coronary syndromes (unstable angina and acute myocardial infarction) are usually caused by atherosclerotic plaque rupture, with consequent activation of the coagulation cascade and circulating platelets. Tissue factor (TF) exposure represents an early event in this pathophysiologic sequence, leading to activation of the extrinsic coagulation pathway and thrombin formation. Tissue factor pathway inhibitor is a naturally occurring inhibitor of the extrinsic pathway. METHODS: In the present study, the gene coding for rabbit TFPI was inserted in a retroviral vector under control of a tetracycline-inducible promoter. Replication-defective, infectious, recombinant retroviruses were used to transfect rabbit carotid arteries with either TFPI or a reporter gene--green fluorescent protein (GFP). RESULTS: Retroviral-mediated arterial gene transfer of TFPI resulted in potent inhibition of intravascular thrombus formation in stenotic and injured rabbit carotid arteries, whereas transfection of the contralateral carotid artery with GFP had no effect on thrombosis. No significant changes in systemic hemostatic variables (prothrombin time and partial thromboplastin time) were observed when thrombosis was inhibited. CONCLUSIONS: These data suggest that retroviral-mediated transfection of the arterial wall with TFPI might represent an attractive approach for the treatment of thrombotic disorders.

Animals↗
PubMedDate not supplied

Antithrombotic effects of recombinant human, active site-blocked factor VIIa in a rabbit model of recurrent arterial thrombosis.

The extrinsic coagulation pathway is activated when circulating factor VII (FVII) gains access to tissue factor (TF) exposed as a consequence of vascular injury. Increasing evidence indicates that this TF-dependent activation of the coagulation plays an important role in the pathophysiology of intravascular thrombus formation. In the present study, we tested the effects of recombinant human, active site-blocked activated FVII (FVIIai) in a rabbit model of carotid artery thrombosis. Cyclic flow variations (CFVs), due to recurrent thrombus formation, were obtained in stenotic rabbit carotid arteries with endothelial injury. Carotid blood flow velocity was measured by a Doppler flow probe. After 30 minutes of CFVs, the animals received FVIIai (100 microg x kg(-1) x min(-1) intracarotid infusion for 10 minutes, n=9). If CFVs were abolished, animals were followed for 30 additional minutes, after which recombinant human activated FVII (FVIIa) was infused into the carotid artery (100 microg x kg(-1) x min(-1) for 10 minutes) to determine whether FVIIai could be displaced from TF by FVIIa, thus restoring CFVs. To establish the duration of action of FVIIai, an additional group of animals received FVIIai at the same dose as above, and after CFVs were inhibited, they were followed until CFVs were restored or for up to 6 hours. To determine whether CFVs could be restored by epinephrine after their abolition with FVIIai, increasing doses of epinephrine were administered to a third group of 6 animals. FVIIai abolished CFVs in 8 of 9 rabbits (P<.01). This effect was reversible, as FVIIa administration restored CFVs in all animals. Prothrombin times and activated partial thromboplastin times did not change significantly throughout the study. One single 10-minute infusion exerted complete antithrombotic effects for at least 6 hours, despite the fact that at this time point, plasma FVIIai levels were well below threshold concentrations. Epinephrine restored CFVs in 3 of 6 animals in which CFVs were inhibited by FVIIai. FVIIai exerts potent antithrombotic effects in this model; these effects were prolonged even after FVIIai was almost completely cleared from the circulation, probably as a result of the tight binding of FVIIai to TF. Thus, FVIIai might represent an antithrombotic substance of potential interest.

Animals↗