Transvenous lead extraction on uninterrupted anticoagulation: A safe approach?

IntroductionCurrent guidelines advocate reviewing peri-procedural anticoagulation on individual case basis for transvenous lead extraction (TLE). We investigated the safety of TLE on uninterrupted warfarin with therapeutic INR.MethodsRetrospective registry of consecutive patients undergoing TLE on uninterrupted warfarin (Warfarin Group) across two centres. Age and sex matched controls not on anticoagulation (No-Warfarin Group) and undergoing TLE over the same time-period were included. Both groups were compared over one-year.Results121 TLEs over 18-months. 22 patients on uninterrupted anticoagulation were compared to 22 controls. Groups were well matched for baseline demographics other than INR. Warfarin group had mean INR of 2.2 ± 0.6 (range 2–3.5). Primary end point was procedural safety and efficacy. Amongst cases, 43/45 (96%) leads were removed in their entirety compared to 37/40 (93%) in controls (p = 0.66). In the cases, these included 44% defibrillator, 47% pace-sense and 9% CS leads of average duration 7yrs. There was no reported tamponade, haemothorax or procedural mortality in either group. One patient amongst cases required inotropic support while two patients amongst controls had device-site haematomas. No significant difference reported in Hb drop post-procedure or overall complication rate between the groups (p = 0.11,0.32). Cox regression showed a significant association between procedural success and device infection, number of leads extracted, serum creatinine (p = 0.03, 0.04, 0.02). Over a 1-year follow-up, there was lead displacement in one case and one control had infection of the re-implanted device.ConclusionTLE can be carried out safely in anticoagulated patients with therapeutic INRs. Larger multicentre studies are required to confirm these findings.     

Roadside Topsoil Concentrations of Lead and Other Heavy Metals in Ibadan,Nigeria

Concentrations of Pb, Zn, Cd, Cu, Cr, Co, and Ni were determined in roadside topsoil collected from locations of varied vehicular traffic densities in the city of Ibadan, Nigeria, with a view to determining the level of contamination and the contribution of traffic density. Levels of Pb, Zn, Cd, and Cu were elevated above background concentrations measured in control areas. Average values (ppm) for all sample locations were Pb — 81±140; Zn — 48±37; Cd — 0.55±0.49; Cu — 17±17; Cr — 22.1±9.6; Co — 7.9±3.8; Ni — 10.5±9.7. Factors of accumulation of metals in roadsides relative to control sites were highest for Pb. Vehicular traffic was not an important source of chromium, cobalt and nickel, for which roadside concentrations were about those of the control sites. Metal concentrations were poorly correlated with traffic volumes. An average of about 60% of total soil concentration of the metals were determined to be held in bioavailable geochemical phases, of which the highest concentrations were mostly held in either the reducible or oxidizable phase. Levels of the metals in the topsoil were generally lower than the soil quality criteria of some developed countries.     

Distribution and mobility of lead in soils at an outdoor shooting range

The distribution of total Pb in surface and subsurface soil horizons at an outdoor shooting range in southeastern Michigan was determined by single extraction elemental analysis (AAS and ICP‐AES). Significant Pb enrichment of the site's soils coincides closely with Pb vapor and particulate matter produced from shot shell primers and the downfall of Pb/Sb pellets associated with the recreational shooting of skeet and trap. Surface concentrations in these locations are 10 to 100 times greater than the background concentration found on adjacent properties. The distribution of Pb in the subsurface soil horizons corresponds to the distribution of Pb at the surface, which suggests the Pb is mobilizing and migrating downward through the vadose zone. This mobilization appears to be occurring despite the clay‐rich nature of the soils, and may be due to the transformation of metallic Pb into soluble Pb compounds of carbonate and sulfate: Both compounds appear to be present in crust material found coating many of the pellets found at the site. The downward migration of soluble Pb is a potential threat to groundwater that is present at the site at a depth of less than 1 m. The protection of surface water quality is also a concern because Pb pellets from the shooting range have been found in the bed sediments of a nearby stream.     

Clean Recycling of Lead-Acid Batteries for Electric Vehicles: A Reply to Socolow and Thomas

This article is stimulated by the analysis of Socolow and Thomas in the first issue of this journal. Our work showed that a lead-acid battery-powered electric vehicle (Ev) would result in more lead being discharged into the environment than a comparable car burning leaded gasoline. Five hundred thousand EVs would lead to a 20% increase in lead use in the United States, and presumably a comparable 20% increase in lead discharges.
The Socolow-Thomas analysis asserts: (I) choosing not to pursue technology that uses toxic materials will unduly constrain the research and development (R&D) in advanced vehicles and limit the options likely to emerge from that research; (2) we do not do a full risk assessment of the lead discharges from lead smelting, battery making and recycling; and (3) in response to regulation the industry might devise a "clean recycling" system.
We doubt the wisdom of increasing R&D on lead batteries because introducing large quantities of lead into cars will pose health risks. The possibility of clean recycling in the future is not an adequate basis for mandating EVs. Proponents of EVs should prove there is no harm to the environment Regulators should not require EVs until there is a reasonable showing of environmental benefit and that the requirement is cost-effective in reducing ozone.