High-on-treatment platelet reactivity predicts adverse outcome after carotid artery stenting: A prospective study.

BACKGROUND AND PURPOSE: High-on-treatment platelet reactivity (HTPR) has been established as a predictor of major adverse cardiovascular events (MACE) in patients undergoing percutaneous coronary interventions on dual antiplatelet therapy (DAPT), but no data are available on its predictive value in patients on DAPT after carotid artery stenting (CAS). We aimed to evaluate the possible association between HTPR in patients on aspirin plus clopidogrel therapy after CAS and subsequent MACE. METHODS: All consecutive patients treated with CAS in a single institution were enrolled in a prospective clinical study. HTPR was evaluated with 5 different laboratory assays carried out just before CAS. MACE incidence (cerebral ischemia, myocardial infarction, stent thrombosis, acute limb ischemia and vascular death) was evaluated at 30 days and thereafter at yearly visits. RESULTS: A total of 300 patients were enrolled in the study, and eight were then excluded because blood samples resulted unsuitable for the laboratory testing or CAS aborted for technical problems. Median follow-up was 5.8 years and during this period 47 MACE occurred. HTPR detected by multiplate electronic aggregometry (MEA) and the VASP phosphorylation assay (VASP) were associated with a significantly enhanced risk of MACE (p = 0.048 and p = 0.038, respectively). However, HTPR to three tests (HTPR3) was more strongly predictive of increased risk of a vascular event at follow up (p = 0.005) at bivariate analysis and also at Cox regression multivariate analysis (p = 0.002). CONCLUSIONS: HTPR to three different assays (mainly to VASP + PFA P2Y+ VerifyNow) in patients on DAPT after CAS has predictive value for subsequent MACE. Prospective studies to assess whether platelet function testing-guided antiplatelet therapy is superior to standard DAPT in patient undergoing CAS should be considered.

Peripheral arterial disease has a strong impact on cardiovascular outcome in patients with acute coronary syndromes: from the START Antiplatelet registry.

BACKGROUND: Peripheral arterial disease (PAD) was reported to increase the risk of new cardiovascular events in patients with acute coronary syndromes (ACS). However, most of the evidence comes from randomized clinical trials. We aimed to assess the impact of PAD on cardiovascular outcome and treatment decisions in ACS patients in a current real-life setting. METHODS: START-ANTIPLATELET is a multicenter registry enrolling ACS patient. Baseline clinical characteristics and treatment at discharge were recorded and follow-up was repeated at 6-months and 1-year. PAD was defined as intermittent claudication and/or previous revascularization. RESULTS: Among 1442 patients enrolled, 103 (7.1%) had PAD. PAD patients were older (71.8 ± 10.6vs66.2 ± 12.6 yrs., p < 0.0001), more frequently hypertensive (90.3vs68.6%, p< 0.0001), hypercholesterolemic (66vs52%, p= 0.037), diabetic (51.5vs24%, p= 0.0001), obese (28.2vs19.3%, p= 0.029) and with previous TIA (7.8vs2.8%, p= 0.005) or stroke (11.7vs3.1%, p< 0.0001). Clinical presentation and acute treatment were similar in non-PAD and PAD patients, but the latter were discharged significantly less frequently on dual antiplatelet therapy (DAPT) (68.9vs85%, p= 0.005). After a median follow-up time of 11.1 months, major cardio/cerebrovascular event-free survival [MACCE, including cardiovascular death, MI, TIA and stroke, target-vessel revascularization (TVR) and major arterial ischemic events] was significantly shorter (9.0vs11.2 months, p= 0.02; HR 3.2, 2.4-8.4) in PAD patients and net adverse cardiovascular events (NACE = MACCE plus major hemorrhages) were significantly more frequent (19.1%vs10.5%, p = 0.049). CONCLUSIONS: PAD identifies a subgroup of ACS patients at significantly increased cardiovascular risk, but these patients tend to be undertreated. Patients admitted for ACS should be screened for PAD and optimal medical therapy at discharge should be implemented.

Nitric oxide-enhancing or -releasing agents as antithrombotic drugs.

Nitric oxide (NO) is a powerful biological mediator provided with a number of activities of relevance for the prevention of thrombosis, like vasodilation, inhibition of platelet adhesion and aggregation, prevention of smooth muscle cell proliferation. Several cells in the circulation release NO, like endothelial cells which are the largest source, red blood cells, platelets and white blood cells, and conditions associated with an impaired production or bioavailability of NO predispose to arterial and venous thrombosis. It seems thus logical to use NO as an antithrombotic agent. However, given the extremely short half-life, limited water solubility and radical nature of this mediator, several chemical strategies to generate drugs releasing NO and/or favouring its endogenous production/bioavailability have been developed. Here we review the pharmacologic approaches to enhance endogenous NO or to induce NO-release developed over the last decades for their effects on platelet activation in vitro and in vivo and on thrombosis, in animal models and in humans. One limitation to the development of NO-releasing agents as antithrombotic drugs is represented by their concomitant vasodilatory action which, by inducing hypotension, limits their applicability. Further pharmacologic and clinical research of novel NO-enhancing and/or -releasing molecules is highly warranted in order to fully exploit the great antithrombotic potential of NO.

Patients with primary antiphospholipid antibody syndrome and without associated vascular risk factors present a normal endothelial function.

INTRODUCTION: Primary antiphospholipid antibody syndrome (PAPS) is characterized by venous or arterial thrombosis and positive antiphospholipid antibodies. It is controversial whether PAPS patients have early atherosclerosis. Endothelial dysfunction is an early event in the natural history of atherosclerosis. Aim of our study was to compare endothelial function of patients with PAPS and no associated risk factors with that of age- and sex-matched controls. MATERIALS AND METHODS: Patients with PAPS, carefully selected to exclude all known risk factors for cardiovascular diseases, estrogen therapy, pregnancy, intake of drugs affecting endothelial function, vitamins or antioxidants, were included in a case-control study. Controls were age- (+/-5 years) and sex-matched subjects with the same exclusion criteria but without PAPS. Flow-mediated dilation of the brachial artery and some plasmatic markers of endothelial and platelet activation were measured. Measures are expressed as mean+/-SEM. RESULTS: Twenty cases (mean age 42+/-4.0 years, 11 females) and 39 controls (mean age 41+/-2.9, 22 females) were studied. FMD was 5.7+/-0.8% in cases (95% CI: 4.1 to 7.3) and 6.8+/-0.5% (5.7 to 7.9) in controls (p=NS). Plasma von Willebrand factor was 128+/-11.3% and 134.2+/-16.1% in cases and controls, respectively (p=NS). Soluble P-selectin and soluble CD40L were 94.1+/-4.9 ng/ml and 0.7+/-0.1 ng/ml in cases and 87.7+/-4.0 ng/ml and 1.0+/-0.2 in controls, respectively (p=NS). In a substudy, circulating progenitor and mature endothelial cells were comparable between the two groups. CONCLUSIONS: Endothelial function in patients with PAPS and no associated risk factors is similar to that of age- and sex- matched controls. These data suggest that the alterations leading to thrombosis in PAPS concern primarily the clotting system.

A new case of acquired Glanzmann's thrombasthenia: diagnostic value of flow cytometry.

BACKGROUND: Acquired Glanzmann's thrombasthenia (aGT) is a rare hemorrhagic disorder caused by autoantibodies, alloantibodies, or paraproteins directed against platelet GPIIb/IIIa. Its diagnosis requires several laboratory assays and mixing tests, which are complex and time consuming. We describe here a new case of aGT and compare different tests for the detection of GPIIb/IIIa-blocking autoantibodies. METHODS: A previously healthy 27-year-old male developed severe mucocutaneous bleeding, despite a normal platelet count, associated with non Hodgkin lymphoma. RESULTS: Blood clotting tests were normal. Bleeding time and PFA-100 were unmeasurable. Platelet aggregation was absent in response to all agonists except ristocetin. Platelet adhesion to collagen at high shear was impaired. Platelet granular content and release was normal. Flow cytometry showed normal binding of some anti-GPIIb/IIIa antibodies (SZ21 and SAP), and decreased binding of others (P2, SZ22, A2A 9/6). Binding of PAC-1, against activated GPIIb/IIIa, and of fibrinogen, was absent. In mixing tests, patient's serum inhibited aggregation, adhesion, and PAC-1 and A2A9/6 binding to control platelets. The patient's antibody, purified by affinity chromatography, recognized purified GPIIb by western blotting. Isolated patient's IgG inhibited platelet aggregation and A2A 9/6 binding by flow cytometry. CONCLUSIONS: Flow cytometry is especially useful for the diagnosis of aGT, being the only test able to characterize both the functional effect and the molecular target of the patient's autoantibody.

Intraplatelet signaling mechanisms of the priming effect of matrix metalloproteinase-2 on platelet aggregation.

OBJECTIVE: Platelets contain and release some matrix metalloproteinases (MMPs), enzymes involved in the degradation of extracellular matrix, and one of these (MMP-2) exerts a proaggregatory effect. We explored the signal transduction mechanisms activated by MMP-2 in human blood platelets. METHODS AND RESULTS: Recombinant, human MMP-2, added before stimulation with subthreshold doses of different agonists, potentiated platelet activation, calcium influx, IP3 formation, and pleckstrin phosphorylation. Wortmannin and LY29400, two PI3-K inhibitors, suppressed the potentiating effects of MMP-2 and preincubation with MMP-2 enhanced the thrombin-induced association of the p85alpha PI3-K subunit with the cytoskeleton and increased the phosphorylation of PKB. Protein tyrosine kinase inhibitors, MAP kinase inhibitors, PLA2 inhibitors, cyclooxygenase inhibitors and antagonists of the P2Y1 and P2Y12 receptors did not affect the potentiating activity of MMP-2 on platelets. CONCLUSION: Our data show that MMP-2, at a concentration released by activated platelets, facilitates platelet activation acting at the level of a second messenger system common to different agonists and related to the activation of PI3-K. Platelet-released MMP-2 may contribute to platelet activation in vivo.

A novel nitric oxide-releasing statin derivative exerts an antiplatelet/antithrombotic activity and inhibits tissue factor expression.

BACKGROUND: NO-releasing statins are new chemical entities, combining HMG-CoA reductase inhibition and slow NO release, that possess stronger anti-inflammatory and antiproliferative activities than the native statins. OBJECTIVE: We evaluated the antithrombotic effects of nitropravastatin (NCX-6550) by assessing its activity on platelet activation and tissue factor (TF) expression by mononuclear cells in vitro and in vivo. METHODS AND RESULTS: In vitro, NCX-6550 inhibited (1) U46619- and collagen-induced platelet aggregation in buffer and plasma; (2) collagen-induced P-selectin expression in whole blood and (3) platelet adhesion to collagen-coated coverslips under high shear stress. These effects were displayed at concentrations of NCX-6550 ranging from 25 to 100 mum, and were totally reverted by the guanylylcyclase inhibitor ODQ (10 microm). Equimolar concentrations of pravastatin had no influence on these parameters of platelet function. LPS- and PMA-induced TF expression by blood mononuclear cells was also inhibited by NCX-6550 (IC50 13 microm), but not by pravastatin, as assessed by functional and immunological assays and by real-time PCR. In a mouse model of platelet pulmonary thromboembolism, induced by the i.v. injection of collagen plus epinephrine, pretreatment with NCX-6550 (24-48 mg kg(-1)) significantly reduced platelet consumption, lung vessel occlusion and mortality. Moreover, nitropravastatin markedly inhibited the generation of procoagulant activity by spleen mononuclear cells and peritoneal macrophages in mice treated with LPS. In these in vivo models too, pravastatin failed to affect platelet activation and monocyte/macrophage procoagulant activity. CONCLUSIONS: Our results show that nitropravastatin exerts strong antithrombotic effects in vitro and in vivo, and may represent an interesting antiatherothrombotic agent for testing in acute coronary syndromes.

Platelets release their lysosomal content in vivo in humans upon activation.

Platelets contain, besides alpha- and delta-granules, lysosomes which store glycohydrolases able to degrade glycoproteins, glycolipids and glycosaminoglycans. While several studies have shown that alpha- and delta-granule secretion takes place "in vivo" in humans upon platelet activation, no data are available on the "in vivo" release of lysosomes. We have studied the release of platelet lysosomal contents "in vivo" in healthy volunteers at a localized site of platelet activation by measuring markers of lysosomal secretion in the blood oozing from a skin wound inflicted for the measurement of the bleeding-time. The levels of beta-N-acetylhexosaminidase (Hex) were 13.1 +/- 0.85 mU/ml in bleeding-time blood and 10.2 +/- 0.66 mU/ml in plasma (p <0.001). Hex in serum was 16.4 +/- 0.72 mU/ml. The levels of beta-galactosidase were also higher in bleeding-time blood than in plasma (0.85 +/- 0.07 mU/ml vs 0.4 +/- 0.05 mU/ml, p <0.001). In bleeding-time blood collected at one minute intervals, Hex rose progressively consistent with ongoing platelet activation and flow-cytometry showed a progressive increase of the expression of LIMP and LAMP-2, two lysosomal associated proteins. In conclusion, our data demonstrate that platelet lysosomal glycohydrolases are released "in vivo" in humans upon platelet activation.

[Temporary defunctionalizing colostomy, a non-indispensable corollary in the Dixon anterior resection of the rectum for treatment of recto-sigmoid carcinoma]. / La colostomia temporanea defunzionalizzante, corollario non indispensabile nella terapia chirurgica di resezione anteriore secondo Dixon nel carcinoma del sigma-retto.

The frequency and sites of carcinoma of the sigmoid colon and rectum are discussed. The complications associated with Dixon's anterior resection of the rectum are described, with particular reference to factors affecting cicatrisation of the colic anastomoses, followed by dehiscences and their degree of seriousness. A personal serier for the years 1969 to 1975 is presented and the advantages and disadvantages of derivative colostomy are explained. Comparison with similar series in which colostomy was or was not employed is used to elicit the reasons why it may be regarded as superfluous.

[Adenomyoma of the gallbladder]. / L'adeno-mioma della colecisti.

The clinical, anatomopathological and radiological data concerning adenomyoma of the gall bladder are considered. The differential features of the pain in patients suffering from adenomyoma and calculosis are reviewed and a line of therapeutic conduct proposed in the light of modern pathogenetic views.