New atrial arrhythmia occurrence in single chamber implantable cardioverter defibrillator patients: A real-world investigation.

INTRODUCTION: A current limitation of single chamber implantable cardioverter defibrillators (ICDs) is the lack of an atrial lead to reliably detect atrial fibrillation (AF) episodes. A novel ventricular based atrial fibrillation (VBAF) detection algorithm was created for single chamber ICDs to assess R-R variability for detection of AF. METHODS: Patients implanted with Visia AF™ ICDs were prospectively enrolled in the Medtronic Product Surveillance Registry from December 15, 2015 to January 23, 2019 and followed with at least 30 days of monitoring with the algorithm. Time to device-detected daily burden of AF ≥ 6 min, ≥6 h, and ≥23 h were reported. Clinical actions after device-detected AF were recorded. RESULTS: A total of 291 patients were enrolled with a mean follow-up of 22.5 ± 7.9 months. Of these, 212 (73%) had no prior history of AF at device implant. However, 38% of these individuals had AF detected with the VBAF algorithm with daily burden of ≥6 min within two years of implant. In these 80 patients with newly detected AF by their ICD, 23 (29%) had a confirmed clinical diagnosis of AF by their provider. Of patients with a clinical diagnosis of AF, nine (39%) were newly placed on anticoagulation, including five of five (100%) patients having a burden >23 h. CONCLUSIONS: Continuous AF monitoring with the new VBAF algorithm permits early identification and actionable treatment for patients with undiagnosed AF that may improve patient outcomes.

Long-term results of the DelIVery for Pulmonary Arterial Hypertension trial.

BACKGROUND: The DelIVery for Pulmonary Arterial Hypertension clinical trial was a multi-center, prospective, single arm, Investigational Device Exemption study utilizing a fully implantable, programmable intravascular delivery system consisting of a pump and a catheter for intravenous treprostinil. The study met its primary endpoint and demonstrated that the intravascular delivery system significantly reduced catheter related complications at 22,000 subject-days of follow-up compared with a predefined objective performance criterion. Here we summarize the results obtained during a 6.4-year follow-up period. METHODS: Throughout study follow-up, participants had clinic visits and medication refills at least every 12 weeks (dependent on the subjects' dose). All adverse events and intravascular delivery system complications were evaluated and recorded. RESULTS: Sixty pulmonary arterial hypertension subjects were followed post device implantation for approximately 282 patient-years (range 87 days to 6.4 years). Of the 60 subjects, 14 died (1 related to intravascular delivery system pump failure), 2 withdrew after lung transplants, and 2 withdrew due to pump pocket infection. No catheter-related bloodstream infections, catheter thrombosis or occlusions, or catheter kinks occurred through 282 patient-years. Two participants had adverse events of abdominal pain, rash, due to subcutaneous treprostinil "leaks" after one catheter puncture and one catheter laceration during pump refill and replacement, respectively. Eight pump failure events occurred: seven pump motor stalls and one early replacement (faulty battery). CONCLUSION: Delivery of treprostinil with an intravascular delivery system is a safe alternative to an external delivery system, while providing enhanced life experiences. To preserve the risk-benefit ratio, treatment at specialized pulmonary arterial hypertension centers is recommended until training is disseminated at other sites.

Prospective, Randomized Study of Direct Anterior Approach vs Posterolateral Approach Total Hip Arthroplasty: A Concise 5-Year Follow-Up Evaluation.

BACKGROUND: Interest in direct anterior approach (DAA) has increased over the last decade. In our previously published study comparing DAA to posterolateral approach (PA), early 3-month benefits were noted in terms of pain and function. There was no difference noted at 6 or 12 months. This study reports average 5-year follow-up of our original study. METHODS: Originally there were 43 DAA patients and 44 PA patients. At an average 5-year follow-up, patients were evaluated clinically with a University of California at Los Angeles activity score, Harris hip score, and Hip Disability and Osteoarthritis Outcome Score Jr Survivorship analysis was calculated. Radiographs were evaluated for loosening and evidence of radiolucent lines. RESULTS: There were 2 deaths 1 in each group, neither was related to the implant or procedure. Four patients were lost to follow-up: 2 in the DAA group and 2 in the PA group. There was no statistical difference between surgical approaches in terms of Harris hip score, University of California at Los Angeles activity score, and Hip Disability and Osteoarthritis Outcome Score Jr. The 7-year survivorship was not significantly different. There were no loose implants at average 5-year follow-up. CONCLUSION: Both DAA and PA yield good results at an average 5-year follow-up in terms of survivorship, function, rate of complications, and radiographic analysis.

Comparative effectiveness of antibiotic-impregnated shunt catheters in the treatment of adult and pediatric hydrocephalus: analysis of 12,589 consecutive cases from 287 US hospital systems.

OBJECT: The real-world effectiveness of antibiotic-impregnated shunt catheters to reduce the incidence of shunt infections is still debated. The literature to date consists mostly of small, single-institution studies. The aim of this study was to assess the incidence of infection for antibiotic-impregnated catheters (AICs) versus standard shunt catheters in a large nationwide administrative database. METHODS: The authors retrospectively reviewed hospital discharge and billing records from the Premier Perspective Database from April 2003 to July 2009 to identify all adult and pediatric patients undergoing de novo ventricular shunt placement. The primary end point was the incidence of shunt infection within 1 year of implantation. Multivariate logistical regression was performed to determine factors associated with increased incidence of infection. RESULTS: A total of 10,819 adult (AIC, 963; standard catheter, 9856) and 1770 pediatric (AIC, 229; standard catheter, 1541) patients underwent ventricular shunt placement in 287 US hospitals. Overall, the incidence of infection was 3.5% in adults (n=380) and 6.6% in pediatric patients (n=116). AICs were associated with significant reduction in infection for both adult (2.2% vs 3.6%, p=0.02) and pediatric (2.6% vs 7.1%, p<0.01) patients. AIC use was associated with reduced infection regardless of hospital size, annual shunt volume, hospital location, or patient risk factors and remained associated with a reduced infection in multivariate analysis for both adult (p=0.02) and pediatric (p=0.02) patients. CONCLUSIONS: The use of antibiotic-impregnated shunt catheters was associated with a reduction in shunt infections for both adult and pediatric patients. This provides further support that AICs may represent a reliable means of reducing shunt infections for both adult and pediatric patients.

Cost savings associated with antibiotic-impregnated shunt catheters in the treatment of adult and pediatric hydrocephalus.

BACKGROUND: Cerebrospinal fluid (CSF) shunt infection is a major cause of morbidity and mortality in the treatment of hydrocephalus and is associated with significant medical cost. Several studies have demonstrated the efficacy of antibiotic-impregnated (AI) shunt catheters in reducing CSF shunt infection; however, providers remain reluctant to adopt AI catheters into practice because of the increased upfront cost. The objective of this study was to determine if the use of AI catheters provided cost savings in a large nationwide database. METHODS: Hospital discharge and billing records from the Premier Perspective Database from 2003-2009 were retrospectively reviewed to identify all adult and pediatric patients undergoing de novo ventricular shunt placement. The incidence of shunt infection within 1 year of implantation was determined. Shunt infection-related cost was defined as all inpatient billing costs incurred during hospitalization for treatment of shunt infection. RESULTS: In 287 U.S. hospitals, 10,819 adult (AI catheters, 963; standard catheters, 9856) and 1770 pediatric (AI catheters, 229; standard catheters, 1541) patients underwent ventricular shunt placement. AI catheters were associated with significant reduction in infection for both adult (2.2% vs. 3.6%, P = 0.02) and pediatric (2.6% vs. 7.1%, P < 0.01) patients. Total infection-related costs were $17,371,320 ($45,714 ± $49,745 per shunt infection) for adult patients and $6,508,064 ($56,104 ± $65,746 per shunt infection) for pediatric patients. Infection-related cost per 100 de novo shunts placed was $120,534 for AI catheters and $162,659 for standard catheters in adult patients and $165,087 for AI catheters and $395,477 for standard catheters in pediatric patients. CONCLUSIONS: In analysis of this large, nationwide database, AI catheters were found to be associated with a significant reduction in infection incidence, resulting in tremendous cost savings. AI catheters were associated with a cost savings of $42,125 and $230,390 per 100 de novo shunts placed in adult and pediatric patients, respectively.

Clinical and kinematic outcomes of a rotating platform posterior stabilized total knee system.

Early post-operative clinical outcomes were analyzed for subjects having a rotating platform (RP) posterior stabilized (PS) total knee arthroplasty (TKA); a subset of which underwent in vivo kinematics and produced kinematic results that compare well with subjects in previous fluoroscopic studies that were deemed excellent in nature. In total, 153 subjects (180 knees) were enrolled in the prospective clinical study. TKAs were performed by three surgeons at three North American centers. Ten subjects were randomly chosen and evaluated under fluoroscopic surveillance. Average active flexion increased from 113.3 (SD=16.6) degrees before surgery to 118.3 (SD=9.9) degrees 12-months post-operatively. American Knee Society (AKS) function score increased from an average of 57.6 (SD=18.8) points pre-operatively to 85.3 (SD=16.6) points 12-months post-operatively. For the kinematic subset, post-operative weight-bearing flexion was 115.9 (SD=8.4),while subjects achieved an average posterior femoral rollback of their lateral condyle of -5.4mm. The average femorotibial axial rotation from full extension to maximum weight-bearing flexion was 3.9 degrees (SD=3.9). Certain kinematic parameters were deemed statistically significant when determining early post-operative clinical success.

Effect of implant design on knee flexion.

From March 2006 to August 2008, 93 subjects (186 knees) underwent simultaneous bilateral total knee arthroplasty performed by eight surgeons at North American centers. This randomized study was conducted to determine whether non-weight-bearing passive flexion was superior for knees receiving a posterior stabilized high flexion device compared to a posterior stabilized standard device in the contra-lateral knee. Weight-bearing single leg active flexion was one secondary endpoint. Follow-up compliance was 92.5%. Results show small, but significant superiority in the motion metrics for the high flexion device compared to the standard device 12 months after surgery, especially for a subgroup of patients with pre-operative flexion less than 120° in both knees. Thus, the ideal candidate for the high flexion device may be one with lesser pre-operative flexion.

Comparison of infection rate with the use of antibiotic-impregnated vs standard extraventricular drainage devices: a prospective, randomized controlled trial.

BACKGROUND: External ventricular drainage (EVD) catheters provide reliable and accurate means of monitoring intracranial pressure and alleviating elevated pressures via drainage of cerebrospinal fluid (CSF). CSF infections occur in approximately 9% of patients. Antibiotic-impregnated (AI) EVD catheters were developed with the goal of reducing the occurrence of EVD catheter-related CSF infections and their associated complications. OBJECTIVE: To present an international, prospective, randomized, open-label trial to evaluate infection incidence of AI vs standard EVD catheters. METHODS: Infection was defined as (1) proven infection, positive CSF culture and positive Gram stain or (2) suspected infection: (A) positive CSF culture with no organisms identified on initial Gram stain; (B) negative CSF culture with a gram-positive or -negative stain; (C) CSF leukocytosis with a white blood cell/red blood cell count >0.02. RESULTS: Four hundred thirty-four patients underwent implantation of an EVD catheter. One hundred seventy-six patients in the AI-EVD cohort and 181 in the standard EVD catheter cohort were eligible for evaluation of infection. The 2 groups were similar in all clinical characteristics. Proven infection was documented in 9 (2.5%) patients (AI: 4 [2.3%] vs standard: 5 [2.8%], P = 1.0). Suspected infection was documented in 31 (17.6%) patients receiving AI and 37 (20.4%) patients receiving standard EVD catheters, P = .504. Duration of time to suspected infection was prolonged in the AI cohort (8.8 ± 6.1 days) compared with the standard EVD cohort (4.6 ± 4.2 days), P = .002. CONCLUSION: AI-EVD catheters were associated with an extremely low rate of catheter-related infections. AI catheters were not associated with risk reduction in EVD infection compared to standard catheters. Use of AI-EVD catheters is a safe option for a wide variety of patients requiring CSF drainage and monitoring, but the efficacy of AI-EVD catheters was not supported in this trial.

Mid-term survivorship results for a rotating-platform knee prosthesis.

Interest in mobile-bearing knee prostheses is increasing in the US market. We studied results at 2 to 5 years with a mobile-bearing system that includes a cobalt-chrome tibial tray and femoral component with a polyethylene cruciate-retaining tibial component insert that allows rotation around a central axis and can be used with cruciate-retaining or posterior-stabilized femoral components. The inserts used in this study were cruciate retaining and did not include the posterior-stabilized design. The goal of this study was to demonstrate the function and safety of this prosthesis along with the lack of spinout, which is a major concern in the mobile-bearing knee. Four hundred thirty-five knees constituted the study cohort and underwent survivorship analysis and complication reporting. Routine clinic evaluations included pre- and postoperative radiographs and Knee Society knee and function scores at 6 and 12 weeks and every 2 years. The most recent follow-up data within 2 to 5 years was included for the study along with survey data. Flexion at most recent follow-up averaged 125°. Knee Society score at most recent visit averaged 88 of 100. Knee Society function score averaged 83 of 100. Radiographic results were available for 226 knees, with 97.3% assessed as normal and 6 with these issues: patella stress fracture (3), aseptic tibial loosening (1), patellar osteolysis (1), and patella aseptic loosening (1). In comparison with the fixed-bearing knee equivalent, this mobile-bearing knee demonstrated at least equivalent results in terms of survivorship, function, and patient satisfaction in the short- and mid-term.

THA with Delta ceramic on ceramic: results of a multicenter investigational device exemption trial.

UNLABELLED: Although the published studies on the outcomes of total hip arthroplasty (THA) performed with currently available ceramic components show high survivorship and low bearing wear at midterm followup, concern over ceramic fracture and squeaking persist. For these reasons, the use of ceramic is limited. Recently, a new alumina matrix composite material (Delta ceramic) with improved material properties was developed to address these concerns. We report the early outcomes and complications of a prospective, randomized, multicenter trial of 263 patients (264 hips) at eight centers, comparing a Delta ceramic-on-ceramic (COC) articulation with a Delta ceramic head-crosslinked polyethylene bearing combination (COP). There were 177 COC hips and 87 COP hips. Complications were reported for all patients, whereas clinical and radiographic results were provided for the 233 patients with minimum 2-year followup (average, 31.2 months; range, 21-49 months). The Harris hip scores and clinical, radiographic, and survivorship outcomes were similar in both groups. There were four (2%) revisions in the COC group and two (2%) in the COP group. We encountered three intraoperative ceramic liner-related events. In addition, one patient receiving the COC underwent revision for chipping of the ceramic liner, and a second had ceramic fragmentation on followup radiographs but has not undergone revision. These liner related complications remain a concern. No patient reported squeaking in either group; this leaves us hopeful the new material will lessen the frequency of squeaking. In the short term, the Delta COC articulation provided similar functional scores and survivorship and complication rates with the ceramic head mated with crosslinked polyethylene. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Sterilization and wear-related failure in first- and second-generation press-fit condylar total knee arthroplasty.

UNLABELLED: We compared the incidence of wear-related failures between two large cohorts of patients undergoing total knee arthroplasty implanted with identical modular tibial trays and polyethylene inserts sterilized by different methods. A total of 1183 second-generation press-fit condylar prostheses having inserts packaged and sterilized in an oxygen-free environment were assessed at a minimum 5-year followup (mean, 7.0 years). Wear-related failure was defined as (1) osteolysis greater than 100 mm2 or (2) revision of the implant resulting from osteolysis, polyethylene wear, chronic synovitis, and/or effusion. Wear-related survivorship was calculated using Kaplan-Meier survival analysis. Results were compared with our previously published study of 1287 first-generation press-fit condylar modular knees having inserts sterilized by gamma irradiation in air at 5-year minimum followup (mean, 7.8 years). The wear-related failure rate for the second-generation design was 1.1% and 10-year survivorship was 97.0% compared with 8.3% failure and 87.7% 10-year survival for the first-generation design. For second-generation components, patient age was the only variable correlated with wear-related failure. For first-generation components sterilized in air, several variables were correlated to wear-related failure with shelf age of the polyethylene insert being the most important factor. These data emphasize the dramatic effect improvements in polyethylene manufacturing, specifically sterilization methods, can have on implant survivorship. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The effect of varus and valgus deformity on results of cementless mobile bearing TKA.

We aimed to determine whether preoperative angular deformity affects survivorship or postoperative alignment after cementless mobile bearing total knee arthroplasty. Nine hundred seventeen knees were grouped according to preoperative mechanical alignment: normal, 0-5 degrees ; abnormal, 6-10 degrees ; severely abnormal, >10 degrees. Ten-year survival estimates were 89.7% for the severely abnormal alignment group, 95.5% for the abnormal alignment group, and 94.9% for the normal alignment group. Postoperatively, normal alignment was restored in 95.6% of knees in the severely abnormal group and 94.5% of knees in the abnormal group. For the normal alignment group, 99.2% of knees remained normally aligned after TKA. These differences in postoperative alignment may explain the severely abnormal alignment group's inferior survivorship outcome. This study shows that cementless mobile bearing implants can be successfully used in a wide range of angulated deformed knees, although preoperatively deformed knees did not do as well as preoperatively undeformed knees.

Factors influencing wear and osteolysis in press-fit condylar modular total knee replacements.

The purpose of this study was to determine the factors influencing wear and osteolysis in patients who have had total knee arthroplasty with the Press-Fit Condylar modular system. Two-thousand ninety-one primary total knee replacements in 1737 patients were done using the Press-Fit Condylar system at three centers. Radiographic and manufacturing data were obtained for 2016 of the 2091 implants (96.4%). For the 1287 of 2016 knees (64%) with more than 5 years of followup, the prevalence of wear-related failure was 8.3%. The 13-year survivorship for all patients was 82.6%. Cox hazards analysis revealed five variables that were correlated with wear-related failure: patient age, patient gender, polyethylene sheet vendor, polyethylene finishing method, and polyethylene shelf age. We were unable to identify one factor as the defining reason for these wear-related failures. The multiple changes in manufacturing methods during the life of this implant may have precluded such a determination. These results may be specific to inserts sterilized in air with gamma irradiation and should not be generalized to current manufacturing techniques. This study emphasizes the potential deleterious effects that small changes in the manufacturing process may have on the outcome of a prosthesis with an initially favorable survivorship.

Uncemented rotating-platform total knee replacement: a five to twelve-year follow-up study.

BACKGROUND: Mobile-bearing knee designs represent an alternative to conventional fixed-bearing total knee arthroplasty. We present the results of a prospective, intermediate-term clinical follow-up study of the bicruciate ligament-sacrificing porous-coated Low Contact Stress rotating-platform total knee design. METHODS: Between February 1984 and January 1994, 528 uncemented primary knee replacements were performed in 421 patients. All patellae were resurfaced with use of the Low Contact Stress rotating patellar component. The average age of the patients at the time of the index procedure was sixty-nine years. The study group included 261 women and 160 men. Patients were evaluated at three months, six months, and yearly thereafter with use of the 100-point New Jersey Orthopaedic Hospital knee-scoring system. In addition, a radiographic analysis of the tibial, femoral, and patellar components was performed at each interval. RESULTS: There were twenty-nine failures that resulted in revision. The Kaplan-Meier estimate of implant survival at twelve years was 89.5% (95% confidence interval, 83.4% to 95.6%). The total clinical scores improved significantly compared with the preoperative scores for the first twelve months postoperatively and then plateaued. Three hundred and twenty-one knees had adequate radiographic follow-up (average, 8.1 years; range, five to twelve years). Zonal radiographic analysis revealed ninety-three instances of radiolucent lines (eighty-two of which measured <1 mm in width), with the greatest number of radiolucent lines (thirty-nine) being located around the tibial tray stem. None of these lines were deemed to be progressive, and no knee with a radiolucent line that measured >2 mm was revised because of failure. CONCLUSIONS: This first-generation uncemented, mobile-bearing, bicruciate ligament-sacrificing knee replacement was associated with a good survival rate and demonstrated clinical efficacy during the five to twelve-year follow-up interval. .