New anticoagulants for the treatment of venous thromboembolism.

In recent years, the significant limitations associated with the use of vitamin K antagonists (VKA) have encouraged the development of new agents. Based upon the central roles played by the serine proteases thrombin and Factor Xa in the blood coagulation cascade, direct thrombin inhibitors and direct Factor Xa inhibitors have been developed. These agents, which include the direct thrombin inhibitor dabigatran etexilate and the Factor Xa inhibitors rivaroxaban and idrabiotaparinux are free from many of the limitations of VKAs. According to the results of available phase III randomized clinical trials, both dabigatran and rivaroxaban are effective and safe enough to qualify as ideal oral anticoagulants for the initial and long-term treatment of patients with acute venous thromboembolism (VTE). Rivaroxaban does not require an initial parenteral treatment and can be given in once daily administrations after the first three weeks. Both of them have limitations for the treatment of patients with severe renal failure, and require further investigations in cancer patients and in pregnant patients with VTE. Both of them lack an antidote.

The optimal duration of anticoagulation in patients with venous thromboembolism: how long is long enough?

The risk of recurrent venous thromboembolism (VTE) approaches 40% of all patients after 10 years of follow-up. This risk is higher in patients with permanent risk factors of thrombosis such as active cancer, prolonged immobilization from medical diseases, and antiphospholipid syndrome; in carriers of several thrombophilic abnormalities, including deficiencies of natural anticoagulants; and in patients with unprovoked presentation. Patients with permanent risk factors of thrombosis should receive indefinite anticoagulation, consisting of subtherapeutic doses of low-molecular-weight heparin in cancer patients, and oral anticoagulants in all other conditions. Patients whose VTE is triggered by major surgery or trauma should be offered three months of anticoagulation. Patients with unprovoked VTE, including carriers of thrombophilia, and those whose thrombotic event is associated with minor risk factors (such as hormonal treatment, minor injuries, long travel) should receive at least three months of anticoagulation. The decision as to go on or discontinue anticoagulation after this period should be individually tailored and balanced against the haemorrhagic risk. Post-baseline variables, such as the D-dimer determination and the ultrasound assessment of residual thrombosis can help identify those patients in whom anticoagulation can be safely discontinued. As a few emerging anti-Xa and anti-IIa compounds seem to induce fewer haemorrhagic complications than conventional anticoagulation, while preserving at least the same effectiveness, they have the potential to open new scenarios for decisions regarding the duration of anticoagulation in patients with VTE.

The value of 64-detector row computed tomography for the exclusion of pulmonary embolism.

Recently, a diagnostic strategy using a clinical decision rule, D-dimer testing and spiral computed tomography (CT) was found to be effective in the evaluation of patients with clinically suspected pulmonary embolism (PE). However, the rate of venous thromboembolic complications in the three-month follow-up of patients with negative CT was still substantial and included fatal events. It was the objective to evaluate the safety of withholding anticoagulants after a normal 64-detector row CT (64-DCT) scan from a cohort of patients with suspected PE. A total of 545 consecutive patients with clinically suspected first episode of PE and either likely pre-test probability of PE (using the simplified Wells score) or unlikely pre-test probability in combination with a positive D-dimer underwent a 64-DCT. 64-DCT scanning was inconclusive in nine patients (1.6%), confirmed the presence of PE in 169 (31%), and ruled out the diagnosis in the remaining 367. During the three-month follow-up of the 367 patients one developed symptomatic distal deep-vein thrombosis (0.27%; 95%CI, 0.0 to 1.51%) and none developed PE (0 %; 95%CI, 0 to 1.0%). We conclude that 64-DCT scanning has the potential to safely exclude the presence of PE virtually in all patients presenting with clinical suspicion of this clinical disorder.

Pyrroloquinoxaline derivatives as high-affinity and selective 5-HT(3) receptor agonists: synthesis, further structure-activity relationships, and biological studies.

The synthesis, pharmacological evaluation, and structure-activity relationships (SARs) of a series of novel pyrroloquinoxalines and heteroaromatic-related derivatives are described. The new pyrroloquinoxaline-related ligands were tested in rat cortex, a tissue expressing high density of 5-HT(3) receptors, and on NG108-15 cells and exhibited IC(50) values in the low nanomolar or subnanomolar range, as measured by the inhibition of [(3)H]zacopride binding. The SAR studies detailed herein delineated a number of structural features required for improving affinity. Some of the ligands were employed as "molecular yardsticks" to probe the spatial dimensions of the lipophilic pockets L1, L2, and L3 in the 5-HT(3) receptor cleft, while the 7-OH pyrroloquinoxaline analogue was designed to investigate hydrogen bonding with a putative receptor site H1 possibly interacting with the serotonin hydroxy group. The most active pyrroloquinoxaline derivatives showed subnanomolar affinity for the 5-HT(3) receptor. In functional studies ([(14)C]guanidinium accumulation test in NG108-15 hybrid cells, in vitro) most of the tested compounds showed clear-cut 5-HT(3) agonist properties, while some others were found to be partial agonists. Several heteroaromatic systems, bearing N-substituted piperazine moieties, have been explored with respect to 5-HT(3) affinity, and novel structural leads for the development of potent and selective central 5-HT(3) receptor agonists have been identified. Preliminary pharmacokinetic studies indicate that these compounds easily cross the blood-brain barrier (BBB) after systemic administration with a brain/plasma ratio between 2 and 20, unless they bear a highly hydrophilic group on the piperazine ring. None of the tested compounds showed in vivo anxiolytic-like activity, but potential analgesic-like properties have been possibly disclosed for this new class of 5-HT(3) receptor agonists.

[Stable angina: long-term results]. / Angina stabile: risultati a lungo termine.

We report on 345 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) for stable angina in a 5-year period, with an average follow-up of 34 months (range 12-72). The primary success rate was 94.5%. The late mortality and incidence of myocardial infarction were 1.5% and 2.1% respectively. The rate of recurrence of angina was 34.5% and required PTCA (28.5%) and/or coronary artery bypass grafting (7%). At the end of follow-up 79.5% of patients were free from angina and a further 10% had improved. Our data confirm the importance of PTCA in stable angina.