Clinical implications of cephalic vein morphometry in routine cardiac implantable electronic device insertion

Background: Morphometric parameters of the venous vasculature constitute an important aspect in successful cardiac implantable electronic device (CIED) insertion. The purpose of this study was to present morpho-anatomical variations of the cephalic vein (CV) and their effect on the course of CIED implantation procedures, based on the patients from our centre. Materials and methods: We analysed contrast venography results obtained during first-time lead placement. Venography was indicated in the cases of problematic lead introduction with either the CV cutdown or axillary/subclavian vein puncture techniques. The 214 cases of venography (15%) performed out of 1425 first-time lead placement in the period 2011–2013 were divided into 9 subgroups according to the most commonly observed CV variations of similar morpho-anatomical features that limited the use of the CV cutdown technique for lead insertion. Results: The following CV morphometric parameters were found to be unfavo­urable in terms of lead placement: CV diameter of ≤ 1 mm (18%), sharp curva­ture of the terminal CV segment as it joined the axillary vein (14%), terminal CV bifurcation (9%), additional CV branches (7%) or tributaries (7%), stenoses (5%), sharply winding course (5%), single CV with a supraclavicular course (4%). Conclusions: The radiographic records obtained during the procedures allowed us to assess the prevalence of those atypical CV variations in our study group, with graphic presentation of characteristic types and sporadically reported CV variations

Selected clinical challenges of a supraclavicular cephalic vein in cardiac implantable electronic device implantation

Background: Supraclavicular variations of the cephalic vein (CV) are detected sporadically. A somewhat more common finding is a CV variation with the typical course of the main vessel but with an additional supraclavicular branch, called the jugulocephalic vein (JCV). The aim of the study was to detect supraclavicular CVs or JCVs via intra-operative venography as well as assess their effects on primary and later revision cardiac implantable electronic device (CIED) procedures in our patients. Materials and methods: We analysed venographic images obtained during CIED procedures at our centre between 2011 and 2015. Out of the 324 venographies conducted during first-time CIED implantation, we identified 14 showing either a supraclavicular course of the CV itself or a persistent JCV. Among revision procedure venographies, we identified 1 case of pertinent CV variations. These vessels had been morphometrically altered by previous medical interventions. Results: Based on topography and morphometric parameters, we identified three anatomical variations of supraclavicular vessels: 2 cases of a supraclavicular CV and 12 cases of an infraclavicular CV accompanied by a persistent supraclavicular JCV (with the diameter larger than that of the main CV in 5 cases and smaller in 7 cases). In 2 cases the enlarged diameter of the JCV was probably due to increased collateral venous flow resulting from thrombotic lesions in the subclavian vein. Conclusions: Supraclavicular CV variations are rare. Nonetheless, they may significantly affect both first-time and later revision CIED procedures. The presence of a supraclavicular vein is an indication for diagnostic venography in the area of the clavipectoral triangle before the CIED procedure

Vasoconstrictive responses of the cephalic vein during first-time cardiac implantable electronic device placement

Background: During cardiac implantable electronic device (CIED) implantation procedures cardiac leads have been mostly introduced transvenously. The associated injury to the selected vessel and adjacent tissues may induce reflex vasoconstriction. The aim of the study was to assess the incidence of cephalic vein (CV) vasoconstriction during first-time CIED implantation.Materials and methods: Of the 146 evaluated first-time CIED implantation procedures conducted in our centre in 2016, we selected those during which CV vasoconstriction was recorded. We focused on the stage of the procedure involving CV cutdown and/or axillary vein (AV)/subclavian vein (SV) puncture for lead insertion. Only cases documented via venography were considered.Results: Vasoconstriction was observed in 11 patients (5 females and 6 males, mean age 59.0 ± 21.2 years). The presence of this phenomenon affected the stage of CIED implantation involving cardiac lead insertion to the venous system, in severe cases, requiring a change of approach from CV cutdown to AV/SV puncture. The extent of vasoconstriction front propagation was limited to the nearest valves. Histological examinations of collected CV samples revealed an altered spatial arrangement of myocytes in the tunica media at the level of leaflet attachment.Conclusions: Cephalic vein vasoconstriction is a rare phenomenon associated with accessing the venous system during first-time CIED implantation. The propagation of CV constriction was limited by the location of the nearest valves

Morphometric parameters of cardiac implantable electronic device (CIED) pocket walls observed on device replacement

Background: The final stage of a conventional de-novo cardiac implantable electronic device (CIED) implantation procedure with transvenous lead insertion involves the formation of a pocket by tissue separation superficial to the pectoralis major muscle in the right or left infraclavicular region, where the device is subsequently placed. Over time, a scar “capsule” is formed around the CIED as a result of normal biological remodelling. Materials and methods: The purpose of this study was to analyse the structure and present the variations of CIED capsules observed during device replacement. The nature and extent of this local tissue remodelling, which had occurred from the time of device implantation to its replacement in 2016 (10 ± 3.1 years), was analysed in 100 patients (mean age 77.1 ± 14.5 years), including 45 women and 55 men. Results: The most prevalent types of “capsules” (70% of cases) were those with similar thickness of both walls or a slightly thicker posterior (< 1.0 mm) than anterior wall (< 0.5 mm). The second most common capsule type (23% of cases) was characterised by a significantly thicker posterior wall of scar tissue (> 1.0 mm). The third group of capsules was characterised by various degrees of wall calcification (7% of cases). Conclusions: The extent and nature of scar tissue structure in the CIED pocket walls seem to correlate with the relative position of cardiac lead loops with respect to the device itself; where the more extensive scarring is likely to result from pocket wall irritation in the capsule formation phase due to lead movements underneath the device. The group of cases with calcified capsules was characterised by “old” device pockets (> 13 years) and the oldest population (patients in their 80s and 90s)

Comparative study of the Martian suprathermal electron depletions based on Mars Global Surveyor, Mars Express and Mars Atmosphere and Volatile EvolutioN missions observations

Nightside suprathermal electron depletions have been observed at Mars by three spacecraft to date: Mars Global Surveyor, Mars Express, and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. This spatial and temporal diversity of measurements allows us to propose here a comprehensive view of the Martian electron depletions through the first multispacecraft study of the phenomenon. We have analyzed data recorded by the three spacecraft from 1999 to 2015 in order to better understand the distribution of the electron depletions and their creation mechanisms. Three simple criteria adapted to each mission have been implemented to identify more than 134,500 electron depletions observed between 125 and 900 km altitude. The geographical distribution maps of the electron depletions detected by the three spacecraft confirm the strong link existing between electron depletions and crustal magnetic field at altitudes greater than ~170 km. At these altitudes, the distribution of electron depletions is strongly different in the two hemispheres, with a far greater chance to observe an electron depletion in the Southern Hemisphere, where the strongest crustal magnetic sources are located. However, the unique MAVEN observations reveal that below a transition region near 160–170 km altitude the distribution of electron depletions is the same in both hemispheres, with no particular dependence on crustal magnetic fields. This result supports the suggestion made by previous studies that these low-altitudes events are produced through electron absorption by atmospheric CO2

The Martian Photoelectron Boundary as Seen by MAVEN

Photoelectron peaks in the 20â 30 eV energy range are commonly observed in the planetary atmospheres, produced by the intense photoionization from solar 30.4 nm photons. At Mars, these photoelectrons are known to escape the planet down its tail, making them tracers for the atmospheric escape. Furthermore, their presence or absence allow to define the soâ called photoelectron boundary (PEB), which separates the photoelectron dominated ionosphere from the external environment. We provide here a detailed statistical analysis of the location and properties of the PEB based on the Mars Atmosphere and Volatile EvolutioN (MAVEN) electron and magnetic field data obtained from September 2014 to May 2016 (including 1696 PEB crossings). The PEB appears as mostly sensitive to the solar wind dynamic and crustal fields pressures. Its variable altitude thus leads to a variable wake cross section for escape (up to â ¼+50%), which is important for deriving escape rates. The PEB is not always sharp and is characterized on average by the following: a magnetic field topology typical for the end of magnetic pileup region above it, more fieldâ aligned fluxes above than below, and a clear change of the altitude slopes of both electron fluxes and total density (that appears different from the ionopause). The PEB thus appears as a transition region between two plasma and fields configurations determined by the draping topology of the interplanetary magnetic field around Mars and much influenced by the crustal field sources below, whose dynamics also impacts the estimated escape rate of ionospheric plasma.Key PointsWe determined the influence of the main driving parameters on the altitude of the photoelectron boundary (PEB)We identified clear plasma and magnetic field characteristics of the PEB and discuss its nature with respect to the ionopauseWe show how the PEB dynamics modifies the tail cross section used for estimating the photoelectrons (and associated ions) escape ratePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139944/1/jgra53813_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139944/2/jgra53813.pd

Altitude dependence of nightside Martian suprathermal electron depletions as revealed by MAVEN observations

The MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft is providing new detailed observations of the Martian ionosphere thanks to its unique orbital coverage and instrument suite. During most periapsis passages on the nightside ionosphere suprathermal electron depletions were detected. A simple criterion was implemented to identify the 1742 depletions observed from 16 November 2014 to 28 February 2015. A statistical analysis reveals that the main ion and electron populations within the depletions are surprisingly constant in time and altitude. Absorption by CO2 is the main loss process for suprathermal electrons, and electrons that strongly peaked around 6 eV are resulting from this interaction. The observation of depletions appears however highly dependent on altitude. Depletions are mainly located above strong crustal magnetic sources above 170 km, whereas the depletions observed for the first time below 170 km are globally scattered onto the Martian surface with no particular dependence on crustal fields

Pressure balance boundaries in the dayside magnetosphere of Mars

International audienceWe use data from the MAVEN and MEX spacecraft to study pressure balance boundaries in the Martian dayside magnetosphere. We use 15 orbit segments from year 2015 when MAVEN and MEX simultaneously were within SZA<60°. The altitude of the derived pressure balance boundaries are estimated and compared to the induced magnetospheric boundary (MB), the ion composition boundary (ICB), the photoelectron boundary (PEB), and the ionopause-like boundary

Double superior vena cava and left brachiocephalic vein agenesis: a rare systemic vein anomaly and potential source of CIED and CVC placement complications

Abnormal systemic vein development produces anomalous veins, which—in the case of persistent left superior vena cava and/or left brachiocephalic vein (BCV)—exhibit considerable topographic and morphometric differences in comparison with their usual anatomy. The nature and extent of those developmental anomalies—detected during intravenous procedures, such as cardiac implantable electronic device (CIED) lead insertion or central venous catheter (CVC) placement—may hinder the procedure itself and/or adversely affect its outcome, both at the stage of cardiac lead advancement through an abnormally shaped vessel and lead positioning within the heart. This may lead to problems in achieving optimal sensing and pacing parameters and in ensuring that the patient cannot feel the pacing impulses. These events accompanied a de novo CIED implantation procedure in the patient with a double SVC and left BCV agenesis, who ultimately required reoperation