Jasmine Patel

16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008.

OBJECTIVES We analyzed the infection burden associated with the implantation of cardiac implantable electrophysiological devices (CIEDs) in the United States for the years 1993 to 2008. BACKGROUND Recent data suggest that the rate of infection following CIED implantation may be increasing. METHODS The Nationwide Inpatient Sample (NIS) discharge records were queried between 1993 and 2008 using the 9th Revision of the International Classification of Diseases (ICD-9-CM). CIED infection was defined as either: 1) ICD-9 code for device-related infection (996.61) and any CIED procedure or removal code; or 2) CIED procedure code along with systemic infection. Patient health profile was evaluated by coding for renal failure, heart failure, respiratory failure, and diabetes mellitus. The infection burden and patient health profile were calculated for each year, and linear regression was used to test for changes over time. RESULTS During the study period (1993 to 2008), the incidence of CIED infection was 1.61%. The annual rate of infections remained constant until 2004, when a marked increase was observed, which coincided with an increase in the incidence of major comorbidities. This was associated with a marked increase in mortality and in-hospital financial charges. CONCLUSIONS The infection burden associated with CIED implantation is increasing over time and is associated with prolonged hospital stays and high financial costs.

Biomaterial-Dependent Characteristics of the Foreign Body Response and S. epidermidis Biofilm Interactions

This chapter presents our efforts to develop a better mechanistic understanding of how biomaterial interactions with blood components lead to alteration of the basic pathophysiologic mechanisms, in particular, inflammation and the foreign body response, which increase the probability of bacterial interactions, colonization, biofilm formation, and infection. In particular, we present perspectives on mechanisms of S. epidermidis biofilm formation, the role of surface chemistry on biofilm formation, the role of bacterial slime production in device infections, the apoptosis of adherent polymorphonuclear leukocytes in the acute inflammatory response, neutrophil mobility and phagocytosis of bacteria on biomaterials, generation of reactive oxygen and nitrogen species by biomaterial-adherent neutrophils, and quorum sensing in S. epidermidis biofilm formation. Our work has focused on infection mechanisms of cardiovascular prostheses and devices where blood hemodynamics and shear stress play important roles in inflammatory cell interactions with biomaterial surfaces. However, we believe that much of our results also are applicable to static implant situations found in orthopedic, cosmetic (plastic), and other surgical areas.

The Clinical Performance of Highly Cross-linked UHMWPE in Hip Replacements

During the 1980s and early 1990s, aseptic loosening and osteolysis emerged as major problems in orthopedics that were perceived to limit the longevity of joint replacements. It was not until the early 1990s that the production of UHMWPE debris at the articulating surface of joint replacements was widely recognized to play a central role in initiating osteolysis. Since that time, orthopedic research efforts have focused increasingly on improving UHMWPE for joint replacements, with the goals of reducing wear and, by implication, improving implant survival, especially for young active patients. Throughout this chapter, we will refer to UHMWPE that has been irradiated with the historical sterilization dose of 25–40 kGy as “conventional” material, whereas UHMWPE that has been irradiated with a dose of greater than 40 kGy will be termed “highly cross-linked” and abbreviated as “HXLPE.”

A Systematic Review of Cost-Effectiveness Analyses of Left Ventricular Assist Devices: Issues and Challenges

BackgroundAdvanced heart failure (HF) can be treated conservatively or aggressively, with left ventricular assist devices (LVADs) and heart transplant (HT) being the most aggressive strategies.ObjectiveThe goal of this review was to identify, describe, critique and summarize published cost-effectiveness analyses on LVADs for adults with HF.MethodsWe conducted a literature search using PubMed and ProQuest DIALOG databases to identify English-language publications from 2006 to 2017 describing cost-effectiveness analyses of LVADs and reviewed them against inclusion criteria. Those that met criteria were obtained for full-text review and abstracted if they continued to meet study requirements.ResultsA total of 12 cost-effectiveness studies (13 articles) were identified, all of which described models; they were almost evenly split between those examining LVADs as destination therapy (DT) or as bridge to transplant (BTT). Studies were Markov or semi-Markov models with one- or three-month cycles that followed patients until death. Inputs came from a variety of sources, with the REMATCH trial and INTERMACS registry common clinical data sources, although some publications also used data from studies at their own institutions. Costs were derived from standard sources in many studies but from individual hospital data in some. Inputs for health utilities, which were used in 11 of 12 studies, were generally derived from two studies. None of the studies reported a societal perspective, that is, included non-medical costs such as caregiving.ConclusionsNo study found LVADs to be cost effective for DT or BTT with base case assumptions, although incremental cost-effectiveness ratios met thresholds for cost effectiveness in some probabilistic analyses. With constant improvements in LVADs and expanding indications, understanding and re-evaluating the cost effectiveness of their use will be critical to making treatment decisions.

TCT-544 Fractional Flow Reserve Utilization in Patients with Stable Coronary Artery Disease

nos: 545 596

Characterization of Outer Insulation in Long-Term-Implanted Leads

Success of pacemakers and implantable cardioverter defibrillators may be limited by premature lead failure. Lead insulation polymers, such as polyurethane (PU) and polydimethylsiloxane (PDMS), are reported to degrade over time in vivo. PU is known to undergo oxidation, whereas PDMS undergoes surface hydrolysis. Previous studies have characterized polymer degradation in vitro, in animals or in short-term human study; however, complex effects of the biochemical and mechanical environment on the lead insulation can only be fully understood by evaluating long-term-implanted leads. Therefore, we established a retrieval program to systematically characterize the chemical and surface changes in 37 of 104 retrieved pacing and defibrillator leads, implanted for ≥5 yr. Fourier transform infrared (FTIR) spectroscopy was used for chemical analysis, and a scanning electron microscope was used for surface degradation evaluation. PDMS leads were investigated for changes in the ratio of Si-O-Si to Si-C peaks, whereas PU degradation was evaluated by changes in ether (C-O-C), carbonyl (C=O), methylene (C-H), and amino (C-N/N-H) peaks. Under SEM, PDMS showed enhanced roughness but no statistical increase in Si-O-Si bonds. PU showed uniform cracking throughout the lead body and statistical changes in each of the oxidation indicative peaks. Overall, both polymers showed surface changes in the physiological environment, but PU was the only material to show chemical changes. This work is a large-scale characterization study on long-term-implanted leads that confirmed PU oxidation but not hydrolysis of PDMS in vivo. It provides important insight for manufacturers when making design improvements and for surgeons when making decisions about lead implantation.

TCT-659 Trends in Revascularization and Mortality for BMS and DES Coronary Stenting Procedures: A Medicare Study of 156,300 patients

It is now common practice to use coronary stents following PTCA to restore blood flow in patients with CAD. The purpose of this study is to evaluate the utilization of bare-metal stents (BMS) and drug-eluting stents (DES) and their revascularization and mortality rates in the U.S. from 1997-2009.

Insights into cardiac pacemaker and defibrillator revision/upgrades

Implantation of cardiac implantable electronic device (CIEDs), both pacemakers (PM) and implantable cardioverter defibrillators (ICDs) has dramatically increased in recent years. Cardiovascular disease causes an estimated 30% of all deaths worldwide. In a 14-month period, a consecutive series of 121 devices (76 ICDs and 45 PMs) were collected as part of an IRB-approved device retrieval program. The criteria for devices to be reprocessable are PMs with remaining projected longevity of greater than 4 years and ICDs with battery voltage greater than 2.95V were noted. Our data suggests that 17–20% of device removals in a teaching hospital may be suitable for re-use in countries with developing economies.