Silent pulmonary embolism in patients with deep venous thrombosis. Incidence and fate in a randomized,controlled trial of anticoagulation versus no anticoagulation

Abstract. Objectives . A high frequency of asymptomatic pulmonary embolism (PE) in patients with deep venous thrombosis (DVT) has been reported, but information about the outcome of the patients with PE remains sparse. The aims of the present study were to assess the prevalence of silent PE in patients with symptomatic, venographically proven DVT, and to evaluate the natural history of silent PE. Design . Consecutive patients from one centre of primary care were included in a randomized, open study with blinded control. All patients gave written, informed consent. Subjects . Eighty-seven consecutive patients with venographically proven DVT and with a perfusionventilation lung scintigraphy performed within 48 h of the DVT diagnosis were included. On the 10th and 60th days the lung scintigraphy was repeated in 80 and 60 patients, respectively. All the patients were followed for 3 months in the out-patient clinic. Interventions . All patients were ambulated from the first day and were allocated randomly to no anticoagulant (non-AC) therapy or to AC therapy with intravenous heparin infusion for at least 6 days and oral AC therapy for 3 months. Results . Forty-three of these patients had a high probability lung scintigraphy for PE. Distal vein and femoral vein thrombosis embolized in 33 and 53% of patients, respectively. The progression rate after 60 days was 3% in both the AC and the non-AC group and after 10 days the rates were 13 and 8%, respectively. Conclusions . A high frequency of silent PE in patients with DVT both above and below the knee is demonstrated. AC treatment did not influence the resolution rate of PE or the rate of clinical PE in a 3-month follow-up period.     

Sodium Nitroprusside Enhances Contractions of the Guinea-pig Isolated Vas Deferens

The effects of sodium nitroprusside on the electrical and mechanical properties of the smooth muscle of the guinea-pig vas deferens, and its responses to transmitter substances, have been investigated by use of the sucrose-gap technique. Isolated longitudinal segments of guinea-pig vas deferens contracted in response to electrical field stimulation (100 V, 0.04–0.1 ms, 1–5 Hz, 10 s train every 60 s) and application of ATP (1 mM) or noradrenaline (10 μM). Sodium nitroprusside (0.1 mM) did not affect resting tension but did enhance contractions evoked by electric-field stimulation but not by ATP or noradrenaline. The sodium nitroprusside-induced enhancement was unaffected by the nitric oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME) (0.1 mM). Conversely, electrically evoked contractions were unaffected by the nitric oxide precursor L-arginine (1 mM) or the nitric oxide donor S-nitroso-N-acetyl-DL-penicillamine (SNAP) (0.1 mM). The amplitudes of electrically evoked excitatory junction potentials (EJPs) were not affected by application of sodium nitroprusside, although it caused a small depolarization of 0.7 ± 0.3 mV. Similarly, the depolarization caused by exogenous application of ATP or noradrenaline was unaffected by the presence of sodium nitroprusside. L-NAME, L-arginine and SNAP did not affect EJP amplitude or baseline membrane potential. It is concluded that sodium nitroprusside enhances electrically evoked contractions of the guinea-pig vas deferens by reducing the threshold voltage for action potential firing in smooth-muscle cells.     

Pattern of Restenosis after Percutaneous Transluminal Coronary Angioplasty of Bifurcation Stenoses

Bifurcation stenoses have been recognized to be at a "high risk" for acute closure during percutaneous transluminal coronary angioplasty. Development of advanced techniques using simultaneous ("kissing") balloon inflation or sequential balloon inflations, using two guidewires to preserve access to both branches while avoiding the trauma produced by inflating two balloons in a small artery simultaneously, has allowed safe and effective dilatation of bifurcation stenoses. Little is known, however, about the restenosis rate and pattern of bifurcation stenoses. This article reports on 44 patients who were treated successfully using the sequential inflation technique on their bifurcation stenoses. A total of 88 lesions were dilated. Restenosis occurred in 25 of the 88 lesions (28%) within 8.5 ± 2.25 months. Eleven patients had restenosis in one vessel while seven patients had restenosis in both branches (18 of 44–41%). All 18 underwent a second PTCA attempt and 15 patients had successful repeat PTCA. Thus, the primary restenosis rate in bifurcation stenosis is acceptably low, occurring in both branches in a minority of cases (7/18). The total restenosis rate is no greater than expected with single vessel PTCA. Repeat PTCA is usually easily accomplished with good secondary success, aided by the fact that the majority of the restenoses involve only one rather than both branches of the bifurcation stenosis. (J Interven Cardiol 1989:2:3)