Brightness of AlGaInAs/InP Multimode Diode Lasers with Different Aperture Widths.

A set of semiconductor lasers with different stripe widths is fabricated based on the AlGaInAs/InP heterostructure with an ultra-narrow waveguide. The key characteristics of the lasers (light-current curves (L-I), current-voltage curves (I-V), and spectral and spatial characteristics) are measured, and their dependence on the stripe width is shown. The operating optical power increases from 1.4 W to 4.3 W; however, the lateral brightness decreases from 1.09 W/(mm*mrad) to 0.65 W/(mm*mrad) as the stripe width increases from 20 to 150 µm.

Retrievable inferior vena cava filter utilization in obstetric patients.

Objectives: The objective of this study is to evaluate patterns of use and outcomes of retrievable inferior vena cava filters (rIVCF) in obstetric patients. Methods: A single center review of consecutive patients who underwent rIVCF placement during pregnancy/postpartum in 2005-2016. A pooled analysis of the relevant cases in the English literature was conducted. Results: The current cohort comprised 24 women, median age 27 [interquartile range 24-30] years. Among 10 filters placed during pregnancy, the most common indication (n = 4) was the need to withhold anticoagulation therapy before delivery, in the presence of acute thrombosis. In the postpartum period, most filters (64%, 9/14) were an adjunct to catheter-directed thrombolytic therapy. Inferior vena cava filters (IVCF)-related complications occurred in seven (29.2%). Retrieval was attempted in 21 patients (87.5%), and was technically successful in 19 (90.5%), for an overall removal rate of 79.1%. Pooled analysis of the literature (n = 98) showed comparable rates for filter removal and complications (81.6%, p = .78 and 24.2%, p = .60, respectively). Suprarenal placement (p = .12) and elective cesarean section (p = .19) did not reduce overall complication and retrieval rates. The estimated radiation dose among pregnant patients who underwent rIVCF placement without adjunct catheter directed thrombolysis (CDT) (mean 695 Gy cm2) was significantly lower than the radiation dose used in postpartum patients (1863 Gy cm2) or in pregnant patients in whom adjunct CDT was utilized (4059 Gy cm2) (p = .001 for both comparisons). Conclusions: Frequent rIVCF-related complications, radiation exposure, and removal failure call for their cautious utilization in obstetric patients. The role of suprarenal placement and elective cesarean section to improve outcomes has yet to be established.

Highly Pathogenic Avian Influenza A(H5N1) Viruses at the Animal-Human Interface in Vietnam, 2003-2010.

Mutation and reassortment of highly pathogenic avian influenza A(H5N1) viruses at the animal-human interface remain a major concern for emergence of viruses with pandemic potential. To understand the relationship of H5N1 viruses circulating in poultry and those isolated from humans, comprehensive phylogenetic and molecular analyses of viruses collected from both hosts in Vietnam between 2003 and 2010 were performed. We examined the temporal and spatial distribution of human cases relative to H5N1 poultry outbreaks and characterized the genetic lineages and amino acid substitutions in each gene segment identified in humans relative to closely related viruses from avian hosts. Six hemagglutinin clades and 8 genotypes were identified in humans, all of which were initially identified in poultry. Several amino acid mutations throughout the genomes of viruses isolated from humans were identified, indicating the potential for poultry viruses infecting humans to rapidly acquire molecular markers associated with mammalian adaptation and antiviral resistance.

Implementation of an institutional protocol to improve inferior vena cava utilization and outcomes.

To evaluate the impact of an institutional protocol on patterns of use and outcomes of inferior vena cava filters (IVCF). Following a multidisciplinary effort, an institutional protocol involving dedicated follow-up of patients receiving IVCF and a physician education program regarding IVCF utilization, was established. We prospectively collected data of patients who received IVCF during 2015-2016, following protocol implementation (POST group). For comparison, we reviewed records of patients who received IVCF during 2009-2014, before implementation of the institutional protocol (PRE group). In the PRE and POST groups, 76 and 38 IVCF per year were inserted respectively, with an overall decrease of 50%. IVCF were more likely to be placed for therapeutic rather than prophylactic indications in the POST compared to the PRE group (P = 0.003). Follow-up rates at our coagulation clinic were significantly higher in the POST than the PRE group (100 vs. 22.9%, P < 0.0001), as were rates of attempted retrieval: 60.5% (23/38) vs. 16.7% (76/455), P < 0.0001. Failed retrieval occurred at similar rates: 15.8% (12/76) vs. 18.2% (4/22), P = 0.75. There was a trend towards a lower thrombotic complication rate in the POST than the PRE group: 2.6 vs. 11.2%, P = 0.16. Implementation of an institutional protocol significantly decreased the use of IVCF and increased the retrieval rate. Such intervention could potentially lead to lower rates of IVCF-related complications in the future.

Indications, complications and outcomes of elderly patients undergoing retrievable inferior vena cava filter placement.

AIM: The utilization of inferior vena cava filter placement for pulmonary embolism prevention in elderly patients has not been well characterized. The present study aimed to review indications, complications and follow-up data of elderly patients undergoing inferior vena cava filter placement. METHODS: A retrospective review was carried out of consecutive admitted patients who underwent inferior vena cava filter insertion at a large university hospital with a level I trauma center. RESULTS: Overall, 455 retrievable filters were inserted between 2009 and 2014. A total of 133 patients (29.2%) were aged ≥70 years. Elderly patients were less likely to have their filter retrieved compared with non-elderly patients (5.3% vs 21.4%, P < 0.001). Filter-related complications occurred in 13% of non-elderly patients and 14.3% of elderly patients (P = 0.72), most of them occurring in the first 3 months after filter placement. Survival among elderly patients with no evidence of active malignancy was similar to the non-elderly patients with a 1-year survival rate of 76.3% versus 82% in non-elderly patients (P = 0.22), and a 2-year survival rate of 73.1% versus 78.6% in non-elderly patients (P = 0.27). Although decreased, survival rates among elderly patients with active cancer were still substantial, with a 1-year survival rate of 45% and 2-year survival rate of 40%. CONCLUSIONS: Elderly patients had significantly lower rates of filter retrieval with similar complication rate. Survival rates among elderly patients were substantial, and in elderly patients with no active cancer were even comparable with non-elderly patients. When feasible, filter retrieval should be attempted in all elderly patients in order to prevent filter-related complications. Geriatr Gerontol Int 2017; 17: 1508-1514.

Selection of antigenically advanced variants of seasonal influenza viruses.

Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent sera to human H1N1 and H3N2 viruses. We also selected antigenic escape variants from human viruses treated with convalescent sera and from mice that had been previously immunized against human influenza viruses. Our pilot studies with past influenza viruses identified escape mutants that were antigenically similar to variants that emerged in nature, establishing the feasibility of our approach. Our studies with contemporary human influenza viruses identified escape mutants before they caused an epidemic in 2014-2015. This approach may aid in the prediction of potential antigenic escape variants and the selection of future vaccine candidates before they become widespread in nature.

Global circulation patterns of seasonal influenza viruses vary with antigenic drift.

Understanding the spatiotemporal patterns of emergence and circulation of new human seasonal influenza virus variants is a key scientific and public health challenge. The global circulation patterns of influenza A/H3N2 viruses are well characterized, but the patterns of A/H1N1 and B viruses have remained largely unexplored. Here we show that the global circulation patterns of A/H1N1 (up to 2009), B/Victoria, and B/Yamagata viruses differ substantially from those of A/H3N2 viruses, on the basis of analyses of 9,604 haemagglutinin sequences of human seasonal influenza viruses from 2000 to 2012. Whereas genetic variants of A/H3N2 viruses did not persist locally between epidemics and were reseeded from East and Southeast Asia, genetic variants of A/H1N1 and B viruses persisted across several seasons and exhibited complex global dynamics with East and Southeast Asia playing a limited role in disseminating new variants. The less frequent global movement of influenza A/H1N1 and B viruses coincided with slower rates of antigenic evolution, lower ages of infection, and smaller, less frequent epidemics compared to A/H3N2 viruses. Detailed epidemic models support differences in age of infection, combined with the less frequent travel of children, as probable drivers of the differences in the patterns of global circulation, suggesting a complex interaction between virus evolution, epidemiology, and human behaviour.

Performance characteristics of qualified cell lines for isolation and propagation of influenza viruses for vaccine manufacturing.

Cell culture is now available as a method for the production of influenza vaccines in addition to eggs. In accordance with currently accepted practice, viruses recommended as candidates for vaccine manufacture are isolated and propagated exclusively in hens' eggs prior to distribution to manufacturers. Candidate vaccine viruses isolated in cell culture are not available to support vaccine manufacturing in mammalian cell bioreactors so egg-derived viruses have to be used. Recently influenza A (H3N2) viruses have been difficult to isolate directly in eggs. As mitigation against this difficulty, and the possibility of no suitable egg-isolated candidate viruses being available, it is proposed to consider using mammalian cell lines for primary isolation of influenza viruses as candidates for vaccine production in egg and cell platforms. To investigate this possibility, we tested the antigenic stability of viruses isolated and propagated in cell lines qualified for influenza vaccine manufacture and subsequently investigated antigen yields of such viruses in these cell lines at pilot-scale. Twenty influenza A and B-positive, original clinical specimens were inoculated in three MDCK cell lines. The antigenicity of recovered viruses was tested by hemagglutination inhibition using ferret sera against contemporary vaccine viruses and the amino acid sequences of the hemagglutinin and neuraminidase were determined. MDCK cell lines proved to be highly sensitive for virus isolation. Compared to the virus sequenced from the original specimen, viruses passaged three times in the MDCK lines showed up to 2 amino acid changes in the hemagglutinin. Antigenic stability was also established by hemagglutination inhibition titers comparable to those of the corresponding reference virus. Viruses isolated in any of the three MDCK lines grew reasonably well but variably in three MDCK cells and in VERO cells at pilot-scale. These results indicate that influenza viruses isolated in vaccine certified cell lines may well qualify for use in vaccine production.

Rapid strategy for screening by pyrosequencing of influenza virus reassortants--candidates for live attenuated vaccines.

BACKGROUND: Live attenuated influenza vaccine viruses (LAIVs) can be generated by classical reassortment of gene segments between a cold adapted, temperature sensitive and attenuated Master Donor Virus (MDV) and a seasonal wild-type (wt) virus. The vaccine candidates contain hemagglutinin (HA) and neuraminidase (NA) genes derived from the circulating wt viruses and the remaining six genes derived from the MDV strains. Rapid, efficient selection of the viruses with 6∶2 genome compositions from the large number of genetically different viruses generated during reassortment is essential for the biannual production schedule of vaccine viruses. METHODOLOGY/PRINCIPAL FINDINGS: This manuscript describes a new approach for the genotypic analysis of LAIV reassortant virus clones based on pyrosequencing. LAIV candidate viruses were created by classical reassortment of seasonal influenza A (H3N2) (A/Victoria/361/2011, A/Ohio/02/2012, A/Texas/50/2012) or influenza A (H7N9) (A/Anhui/1/2013) wt viruses with the MDV A/Leningrad/134/17/57(H2N2). Using strain-specific pyrosequencing assays, mixed gene variations were detected in the allantoic progenies during the cloning procedure. The pyrosequencing analysis also allowed for estimation of the relative abundance of segment variants in mixed populations. This semi-quantitative approach was used for selecting specific clones for the subsequent cloning procedures. CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that pyrosequencing analysis is a useful technique for rapid and reliable genotyping of reassortants and intermediate clones during the preparation of LAIV candidates, and can expedite the selection of vaccine virus candidates.

Characterization of reverse genetics-derived cold-adapted master donor virus A/Leningrad/134/17/57 (H2N2) and reassortants with H5N1 surface genes in a mouse model.

Live attenuated influenza vaccines (LAIV) offer significant advantages over subunit or split inactivated vaccines to mitigate an eventual influenza pandemic, including simpler manufacturing processes and more cross-protective immune responses. Using an established reverse genetics (rg) system for wild-type (wt) A/Leningrad/134/1957 and cold-adapted (ca) A/Leningrad/134/17/1957 (Len17) master donor virus (MDV), we produced and characterized three rg H5N1 reassortant viruses carrying modified HA and intact NA genes from either A/Vietnam/1203/2004 (H5N1, VN1203, clade 1) or A/Egypt/321/2007 (H5N1, EG321, clade 2) virus. A mouse model of infection was used to determine the infectivity and tissue tropism of the parental wt viruses compared to the ca master donor viruses as well as the H5N1 reassortants. All ca viruses showed reduced replication in lungs and enhanced replication in nasal epithelium. In addition, the H5N1 HA and NA enhanced replication in lungs unless it was restricted by the internal genes of the ca MDV. Mice inoculated twice 4 weeks apart with the H5N1 reassortant LAIV candidate viruses developed serum hemagglutination inhibition HI and IgA antibody titers to the homologous and heterologous viruses consistent with protective immunity. These animals remained healthy after challenge inoculation with a lethal dose with homologous or heterologous wt H5N1 highly pathogenic avian influenza (HPAI) viruses. The profiles of viral replication in respiratory tissues and the immunogenicity and protective efficacy characteristics of the two ca H5N1 candidate LAIV viruses warrant further development into a vaccine for human use.

Structural stability of influenza A(H1N1)pdm09 virus hemagglutinins.

UNLABELLED: The noncovalent interactions that mediate trimerization of the influenza hemagglutinin (HA) are important determinants of its biological activities. Recent studies have demonstrated that mutations in the HA trimer interface affect the thermal and pH sensitivities of HA, suggesting a possible impact on vaccine stability (). We used size exclusion chromatography analysis of recombinant HA ectodomain to compare the differences among recombinant trimeric HA proteins from early 2009 pandemic H1N1 viruses, which dissociate to monomers, with those of more recent virus HAs that can be expressed as trimers. We analyzed differences among the HA sequences and identified intermolecular interactions mediated by the residue at position 374 (HA0 numbering) of the HA2 subdomain as critical for HA trimer stability. Crystallographic analyses of HA from the recent H1N1 virus A/Washington/5/2011 highlight the structural basis for this observed phenotype. It remains to be seen whether more recent viruses with this mutation will yield more stable vaccines in the future. IMPORTANCE: Hemagglutinins from the early 2009 H1N1 pandemic viruses are unable to maintain a trimeric complex when expressed in a recombinant system. However, HAs from 2010 and 2011 strains are more stable, and our work highlights that the improvement in stability can be attributed to an E374K substitution in the HA2 subunit of the stalk that emerged naturally in the circulating viruses.

Multiple reassortment events among highly pathogenic avian influenza A(H5N1) viruses detected in Bangladesh.

In Bangladesh, little is known about the genomic composition and antigenicity of highly pathogenic avian influenza A(H5N1) viruses, their geographic distribution, temporal patterns, or gene flow within the avian host population. Forty highly pathogenic avian influenza A(H5N1) viruses isolated from humans and poultry in Bangladesh between 2008 and 2012 were analyzed by full genome sequencing and antigenic characterization. The analysis included viruses collected from avian hosts and environmental sampling in live bird markets, backyard poultry flocks, outbreak investigations in wild birds or poultry and from three human cases. Phylogenetic analysis indicated that the ancestors of these viruses reassorted (1) with other gene lineages of the same clade, (2) between different clades and (3) with low pathogenicity avian influenza A virus subtypes. Bayesian estimates of the time of most recent common ancestry, combined with geographic information, provided evidence of probable routes and timelines of virus spread into and out of Bangladesh.

Investigating a crow die-off in January-February 2011 during the introduction of a new clade of highly pathogenic avian influenza virus H5N1 into Bangladesh.

We investigated unusual crow mortality in Bangladesh during January-February 2011 at two sites. Crows of two species, Corvus splendens and C. macrorhynchos, were found sick and dead during the outbreaks. In selected crow roosts, morbidity was ~1 % and mortality was ~4 % during the investigation. Highly pathogenic avian influenza virus H5N1 clade 2.3.2.1 was isolated from dead crows. All isolates were closely related to A/duck/India/02CA10/2011 (H5N1) with 99.8 % and A/crow/Bangladesh/11rs1984-15/2011 (H5N1) virus with 99 % nucleotide sequence identity in their HA genes. The phylogenetic cluster of Bangladesh viruses suggested a common ancestor with viruses found in poultry from India, Myanmar and Nepal. Histopathological changes and immunohistochemistry staining in brain, pancreas, liver, heart, kidney, bursa of Fabricius, rectum, and cloaca were consistent with influenza virus infection. Through our limited investigation in domesticated birds near the crow roosts, we did not identify any samples that tested positive for influenza virus A/H5N1. However, environmental samples collected from live-bird markets near an outbreak site during the month of the outbreaks tested very weakly positive for influenza virus A/H5N1 in clade 2.3.2.1-specific rRT-PCR. Continuation of surveillance in wild and domestic birds may identify evolution of new avian influenza virus and associated public-health risks.

Application of real time RT-PCR for the genetic homogeneity and stability tests of the seed candidates for live attenuated influenza vaccine production.

Development and improvement of quality control tests for live attenuated vaccines are a high priority because of safety concerns. Live attenuated influenza vaccine (LAIV) viruses are 6:2 reassortants containing the hemagglutinin (HA) and neuraminidase (NA) gene segments from circulating influenza viruses to induce protective immune responses, and the six internal gene segments from a cold-adapted Master Donor Virus (MDV). LAIV candidate viruses for the 2012-2013 seasons, A/Victoria/361/2011-CDC-LV1 (LV1) and B/Texas/06/2011-CDC-LV2B (LV2B), were created by classical reassortment of A/Victoria/361/2011 and MDV-A A/Leningrad/134/17/57 (H2N2) or B/Texas/06/2011 and MDV-B B/USSR/60/69. In an attempt to provide better identity and stability testing for quality control of LV1 and LV2B, sensitive real-time RT-PCR assays (rRT-PCR) were developed to detect the presence of undesired gene segments (HA and NA from MDV and the six internal genes from the seasonal influenza viruses). The sensitivity of rRT-PCR assays designed for each gene segment ranged from 0.08 to 0.8EID50 (50% of Egg Infectious Dose) per reaction for the detection of undesired genes in LV1 and from 0.1 to 1EID50 per reaction for the detection of undesired genes in LV2B. No undesired genes were detected either before or after five passages of LV1 or LV2B in eggs. The complete genome sequencing of LV1 and LV2B confirmed the results of rRT-PCR, demonstrating the utility of the new rRT-PCR assays to provide the evidence for the homogeneity of the prepared vaccine candidate.

Antiviral susceptibility of highly pathogenic avian influenza A(H5N1) viruses isolated from poultry, Vietnam, 2009-2011.

We assessed drug susceptibilities of 125 avian influenza A(H5N1) viruses isolated from poultry in Vietnam during 2009-2011. Of 25 clade 1.1 viruses, all possessed a marker of resistance to M2 blockers amantadine and rimantadine; 24 were inhibited by neuraminidase inhibitors. One clade 1.1 virus contained the R430W neuraminidase gene and reduced inhibition by oseltamivir, zanamivir, and laninamivir 12-, 73-, and 29-fold, respectively. Three of 30 clade 2.3.4 viruses contained a I223T mutation and showed 7-fold reduced inhibition by oseltamivir. One of 70 clade 2.3.2.1 viruses had the H275Y marker of oseltamivir resistance and exhibited highly reduced inhibition by oseltamivir and peramivir; antiviral agents DAS181 and favipiravir inhibited H275Y mutant virus replication in MDCK-SIAT1 cells. Replicative fitness of the H275Y mutant virus was comparable to that of wildtype virus. These findings highlight the role of drug susceptibility monitoring of H5N1 subtype viruses circulating among birds to inform antiviral stockpiling decisions for pandemic preparedness.

Structural and antigenic variation among diverse clade 2 H5N1 viruses.

Antigenic variation among circulating H5N1 highly pathogenic avian influenza A viruses mandates the continuous production of strain-specific pre-pandemic vaccine candidates and represents a significant challenge for pandemic preparedness. Here we assessed the structural, antigenic and receptor-binding properties of three H5N1 HPAI virus hemagglutinins, which were recently selected by the WHO as vaccine candidates [A/Egypt/N03072/2010 (Egypt10, clade 2.2.1), A/Hubei/1/2010 (Hubei10, clade 2.3.2.1) and A/Anhui/1/2005 (Anhui05, clade 2.3.4)]. These analyses revealed that antigenic diversity among these three isolates was restricted to changes in the size and charge of amino acid side chains at a handful of positions, spatially equivalent to the antigenic sites identified in H1 subtype viruses circulating among humans. All three of the H5N1 viruses analyzed in this study were responsible for fatal human infections, with the most recently-isolated strains, Hubei10 and Egypt10, containing multiple residues in the receptor-binding site of the HA, which were suspected to enhance mammalian transmission. However, glycan-binding analyses demonstrated a lack of binding to human α2-6-linked sialic acid receptor analogs for all three HAs, reinforcing the notion that receptor-binding specificity contributes only partially to transmissibility and pathogenesis of HPAI viruses and suggesting that changes in host specificity must be interpreted in the context of the host and environmental factors, as well as the virus as a whole. Together, our data reveal structural linkages with phylogenetic and antigenic analyses of recently emerged H5N1 virus clades and should assist in interpreting the significance of future changes in antigenic and receptor-binding properties.

Outbreak of variant influenza A(H3N2) virus in the United States.

BACKGROUND: Variant influenza virus infections are rare but may have pandemic potential if person-to-person transmission is efficient. We describe the epidemiology of a multistate outbreak of an influenza A(H3N2) variant virus (H3N2v) first identified in 2011. METHODS: We identified laboratory-confirmed cases of H3N2v and used a standard case report form to characterize illness and exposures. We considered illness to result from person-to-person H3N2v transmission if swine contact was not identified within 4 days prior to illness onset. RESULTS: From 9 July to 7 September 2012, we identified 306 cases of H3N2v in 10 states. The median age of all patients was 7 years. Commonly reported signs and symptoms included fever (98%), cough (85%), and fatigue (83%). Sixteen patients (5.2%) were hospitalized, and 1 fatal case was identified. The majority of those infected reported agricultural fair attendance (93%) and/or contact with swine (95%) prior to illness. We identified 15 cases of possible person-to-person transmission of H3N2v. Viruses recovered from patients were 93%-100% identical and similar to viruses recovered from previous cases of H3N2v. All H3N2v viruses examined were susceptible to oseltamivir and zanamivir and resistant to adamantane antiviral medications. CONCLUSIONS: In a large outbreak of variant influenza, the majority of infected persons reported exposures, suggesting that swine contact at an agricultural fair was a risk for H3N2v infection. We identified limited person-to-person H3N2v virus transmission, but found no evidence of efficient or sustained person-to-person transmission. Fair managers and attendees should be aware of the risk of swine-to-human transmission of influenza viruses in these settings.

Highly pathogenic avian influenza A(H7N3) virus in poultry workers, Mexico, 2012.

We identified 2 poultry workers with conjunctivitis caused by highly pathogenic avian influenza A(H7N3) viruses in Jalisco, Mexico. Genomic and antigenic analyses of 1 isolate indicated relatedness to poultry and wild bird subtype H7N3 viruses from North America. This isolate had a multibasic cleavage site that might have been derived from recombination with host rRNA.

Emergence of multiple clade 2.3.2.1 influenza A (H5N1) virus subgroups in Vietnam and detection of novel reassortants.

Phylogenetic analyses of 169 influenza A(H5N1) virus genomes were conducted for samples collected through active surveillance and outbreak responses in Vietnam between September 2010 and September 2012. While clade 1.1 viruses persisted in southern regions, three genetically distinct subgroups of clade 2.3.2.1 were found in northern and central Vietnam. The identification of each subgroup corresponded with detection of novel reassortants, likely due to their overlapping circulation throughout the country. While the previously identified clade 1.1 and A/Hubei/1/2010-like 2.3.2.1 genotypes remained the predominant viruses detected, four viruses were found to be reassortants between A/Hubei/1/2010-like (HA, NA, PB2, PB1, PA, NP) and A/duck/Vietnam/NCVD-885/2010-like (M, NS) viruses and one virus was identified as having A/duck/Vietnam/NCVD-885/2010-like HA, NA, PB1, and NP with A/Hubei/1/2010-like PB2 and PA genes. Additionally, clade 2.3.2.1 A/Hong Kong/6841/2010-like viruses, first detected in mid-2012, were identified as reassortants comprised of A/Hubei/1/2010-like PB2 and PA and A/duck/Vietnam/NCVD-885/2010-like PB1, NP, NA, M, NS genes.

Patient radiation exposure during percutaneous endovascular revascularization of the lower extremity.

BACKGROUND: Percutaneous endovascular revascularization is emerging as the first line treatment for peripheral artery disease for both intermittent claudication and chronic critical limb ischemia. Radiation doses for these interventions have not been well documented. METHODS: A single center retrospective study of therapeutic endovascular lower extremity interventions performed between September 2006 and December 2011 was undertaken. Collected data included patient demographics, procedure indication, procedural access, anatomic location of occlusive disease (pelvis, thigh, below-knee, or multilevel), and radiation exposure parameters including dose area product (DAP) and fluoroscopy time. RESULTS: Data was available for 382 procedures performed in 313 patients. Eighteen procedures bilateral procedures were excluded. Access site and complete anatomic data were available for 346 procedures. DAP was significantly higher for procedures performed in the pelvis compared with thigh procedures (179.6 vs 63.2 Gy*cm(2); P < .0001) and below-knee procedures (179.6 vs 28.9 Gy*cm(2); P < .0001), despite shorter fluoroscopy times (11.8 vs 16.4 minutes; P < .0001 and 11.1 vs 31.06 minutes; P < .0001, respectively). Procedure access-site affected radiation dose as well; contralateral up-and-over access resulted in a higher DAP than antegrade access (112.2 vs 42.6 Gy*cm(2); P < .0001). In a multivariable analysis, anatomic location of the procedure showed the strongest association with radiation dose (P < .0001). CONCLUSIONS: Percutaneous endovascular revascularization for lower extremity peripheral artery disease involves a substantial radiation dose, comparable, on average, to a computed tomography scan of the abdomen and pelvis. Procedures performed in the pelvis for intermittent claudication involve more radiation than thigh or below-knee procedures for chronic critical limb ischemia. Radiation dose should be considered when planning these procedures.