Extended out-of-hospital low-molecular-weight heparin prophylaxis against deep venous thrombosis in patients after elective hip arthroplasty: a systematic review.

PURPOSE: Evidence-based medicine guidelines based on venographic end points recommend in-hospital prophylaxis with low-molecular-weight heparin (LMWH) in patients having elective hip surgery. Emerging data suggest that out-of-hospital use may offer additional protection; however, uncertainty remains about the risk-benefit ratio. To provide clinicians with a practical pathway for translating clinical research into practice, we systematically reviewed trials comparing extended out-of-hospital LMWH prophylaxis versus placebo. DATA SOURCES: Studies were identified by 1) searching PubMed, MEDLINE, and the Cochrane Library Database for reports published from January 1976 to May 2001; 2) reviewing references from retrieved articles; 3) scanning abstracts from conference proceedings; and 4) contacting pharmaceutical companies and investigators of the original reports. STUDY SELECTION: Randomized, controlled trials comparing extended out-of-hospital prophylaxis with LMWH versus placebo in patients having elective hip arthroplasty. DATA EXTRACTION: Two reviewers extracted data independently. Reviewers evaluated study quality by using a validated four-item instrument. DATA SYNTHESIS: Six of seven original articles met the defined inclusion criteria. The included studies were double-blind trials that used proper randomization procedures. Compared with placebo, extended out-of-hospital prophylaxis decreased the frequency of all episodes of deep venous thrombosis (placebo rate, 150 of 666 patients [22.5%]; relative risk, 0.41 [95% CI, 0.32 to 0.54; P < 0.001]), proximal venous thrombosis (placebo rate, 76 of 678 patients [11.2%]; relative risk, 0.31 [CI, 0.20 to 0.47; P < 0.001]), and symptomatic venous thromboembolism (placebo rate, 36 of 862 patients [4.2%]; relative risk, 0.36 [CI, 0.20 to 0.67; P = 0.001]). Major bleeding was rare, occurring in only one patient in the placebo group. CONCLUSIONS: Extended LMWH prophylaxis showed consistent effectiveness and safety in the trials (regardless of study variations in clinical practice and length of hospital stay) for venographic deep venous thrombosis and symptomatic venous thromboembolism. The aggregate findings support the need for extended out-of-hospital prophylaxis in patients undergoing hip arthroplasty surgery.

Timing of initial administration of low-molecular-weight heparin prophylaxis against deep vein thrombosis in patients following elective hip arthroplasty: a systematic review.

BACKGROUND: Perioperative and postoperative venous thrombosis are common in patients undergoing elective hip surgery. Prophylactic regimens include subcutaneous low-molecular-weight heparin 12 hours or more before or after surgery and oral anticoagulants. Recent clinical trials suggest that low-molecular-weight heparin initiated in closer proximity to surgery is more effective than the present clinical practice. We performed a systematic review of the literature to assess the efficacy and safety of low-molecular-weight heparin administered at different times in relation to surgery vs oral anticoagulant prophylaxis. METHODS: Reviewers (A.F.M. and S.M.M.) identified studies by searching MEDLINE, reviewing references from retrieved articles, scanning abstracts from conference proceedings, and contacting investigators and pharmaceutical companies. Randomized trials comparing low-molecular-weight heparin administered at different times relative to surgery with oral anticoagulants in patients undergoing elective hip arthroplasty, evaluated using contrast phlebography, were selected. Two reviewers (A.F.M. and S.M.M.) extracted data independently. RESULTS: The literature review identified 4 randomized trials meeting predefined inclusion criteria. The results indicate that low-molecular-weight heparin initiated in close proximity to surgery resulted in absolute risk reductions of 11% to 13% for deep vein thrombosis, corresponding to relative risk reductions of 43% to 55% compared with oral anticoagulants. Low-molecular-weight heparin initiated 12 hours before surgery or 12 to 24 hours postoperatively was not more effective than oral anticoagulants. Low-molecular-weight heparin initiated postoperatively in close proximity to surgery at half the usual dose was not associated with a clinically or statistically significant increase in major bleeding rates (P =.16). CONCLUSIONS: The timing of initiating low-molecular-weight heparin significantly influences antithrombotic effectiveness. The practice of delayed initiation of low-molecular-weight heparin prophylaxis results in suboptimal antithrombotic effectiveness without a substantive safety advantage.

Neuronal form in the central nervous system of the tadpole larva of the ascidian Ciona intestinalis.

The dorsal tubular central nervous system (CNS) of the ascidian tadpole larva is a diagnostic feature by which the chordate affinities of this group, as a whole, are recognized. We have used two methods to identify larval neurons of Ciona intestinalis. The first is serial electron microscopy (EM), as part of a dedicated study of the visceral ganglion (1), and the second is the transient transfection of neural plate progeny with green fluorescent protein (GFP) (2), to visualize the soma and its neurites of individual neurons in whole-mounted larvae of C. intestinalis. Our observations reveal that ascidian larval neurons are simple inform, with a single axonal neurite arising from a soma that is either monopolar or has only very few, relatively simple neurites arising from it, as part of a presumed dendritic arbor. Somata in the visceral ganglion giving rise to axons descending in the caudal nerve cord are presumed to be those of motor neurons.

Low-molecular-weight heparin prophylaxis: preoperative versus postoperative initiation in patients undergoing elective hip surgery.

Administration of low-molecular-weight heparin prophylaxis in elective hip implant patients commonly begins 12 h preoperatively in European practices to optimize effectiveness, and 12 to 24 h postoperatively in North American practices to optimize safety. A meta-analysis comparing these two treatment regimes revealed that preoperative initiation demonstrated greater efficacy and superior safety for patients (10.0% rate of total deep-vein thrombosis vs. 15.3%, P = .023). In addition to the pre/postsurgical debate, proximity of initiation of low-molecular-weight heparin in relation to surgery is an issue of critical importance. Recent studies revealed that beginning therapy immediately within 2 h preoperatively or 6 h postoperatively dramatically decreased the risk of venous thrombosis. An investigation of low-molecular-weight heparin prophylaxis initiated 2 h before elective hip surgery or approximately 6 h after surgery compared with warfarin sodium revealed that total and proximal deep-vein thrombosis rates were reduced in patients receiving low-molecular-weight heparin compared with warfarin. The frequencies of deep-vein thrombosis for patients receiving preoperative and postoperative dalteparin vs. warfarin for all deep-vein thrombosis were 36 of 337 (10.7%, P < .001) and 44 of 336 (13.1%, P < .001) vs. 81 of 338 (24.0%); and for proximal deep-vein thrombosis were 3 of 354 (0.8%, P = .035) and 3 of 358 (0.8%, P = .033) vs. 11 of 363 (3.0%). Relative risk reductions for the dalteparin groups vs. warfarin ranged from 45% to 72%. In this case, low-molecular-weight heparin administered in close proximity to surgery provided superior efficacy over warfarin. Major bleeding was significantly increased with the preoperative regimen but not the postoperative regimen.

Survival after pelvic lymphadenectomy and radical cystectomy in patients with lymph-node metastatic transitional-cell carcinoma of the bladder.

The objective of this study was to determine the clinical outcome of patients with invasive transitional cell carcinoma of the bladder and pelvic lymph node metastases treated by radical cystectomy and bilateral pelvic lymphadenectomy in a single institution. From January 1980 to December 1993, 116 patients with transitional cell carcinoma of the bladder underwent bilateral pelvic lymphadenectomy and radical cystectomy at the Montreal General Hospital. Of these patients, 25 (21.6%) were found to have nodal metastases and form the basis of this retrospective analysis. Extent of nodal disease was as follows: 7 (28%) with N1, 17 (68%) with N2, and 1 (4%) patient with N3 disease. Of the 25 patients, 9 (36%) were alive with no evidence of disease and 1 (4%) died at 42 months from cardiovascular disease without clinical evidence of cancer recurrence. The median follow-up interval for these 10 patients was 26.5 months (mean, 31.4 months; range, 7-104 months). Fourteen (56%) patients died of recurrent bladder cancer and one patient was alive with systemic disease at 14 months. The median survival was estimated at 27 months, with 73% alive at 1 year, 51% alive at 2 years, and 33% alive at 3 years. Our data suggests that long-term survival free of disease can be achieved by radical surgery in some patients with node-positive bladder cancer.

The diagnostic significance of serum creatine kinase-BB isoenzyme in adenocarcinoma of prostate.

The relative diagnostic usefulness of total serum acid phosphatase, tartrate-inhibited fraction of acid phosphatase, immunoreactive prostatic acid phosphatase, and creatine kinase-BB isoenzyme was evaluated in 30 patients with biopsy-proven adenocarcinoma of prostate. The total and tartrate-inhibited acid phosphatase, measured by standard chemical methods, were elevated in 8 patients with stage D disease. The radioimmunoassay (RIA) method confirmed these abnormal values and also indicated the presence of elevated prostatic serum acid phosphatase in 3 additional patients. The electrophoretic fractionation of total serum creatine kinase (CK) into its various isoenzyme components showed the presence of CK-BB isoenzyme in 8 patients. In 5 of these patients with detectable CK-BB isoenzyme, RIA values for prostatic acid phosphatase were also elevated. Histologic studies of the prostatic tissues revealed that the presence of serum CK-BB was invariably associated with poorly differentiated adenocarcinoma of prostate. The results of the present studies indicate that 1) with simultaneous measurements of serum CK-BB and immunoreactive prostatic acid phosphatase laboratory confirmation of prostatic cancer can be obtained in 50 per cent of patients; 2) determination of total and tartrate-inhibited acid phosphatase along with CK-BB and immunoreactive prostatic acid phosphatase does not increase the frequency of correct diagnosis; and 3) the presence of serum CL-BB isoenzyme is suggestive of poorly differentiated adenocarcinoma of prostate.

Vasectomy: benefits and risks.

Bilateral occlusion of the vas deferens, vasectomy, is progressively becoming the method of choice for couples seeking permanent contraception at a younger age, with smaller families. They are apparently well-informed and view the procedure as a natural step. Vasectomy is an inexpensively performed office procedure that causes minimal disruption of routine and has a high degree of community acceptance. The risks of significant hematoma, infection, discomfort and other sequelae are within acceptable limits. Improved techniques will continue to reduce the small failure rate. Antibodies observed in half of the patients have not been linked to systemic disease, although they are a hazard for the one patient in 500 returning for a vasovasostomy. Refinements in microsurgery and availability of artificial insemination enhance vasectomy as the method of choice. Evidently, extending the minimum time of sterility confirmation permits detection of occasional recanalization from technical failures. Adequate screening of the couple's motivation and expectations can prevent the rare psychologic disturbances, the greatest risk with this procedure and a problem associated with all options. For the male, there is no competitive technique at this time. In a world striving for equal rights, where the female still carries the burden of temporary contraception, the simplicity and popularity of vasectomy for permanent contraception add the desired undertones of social equilibrium.