Concurrent Hardware Removal is Associated With Increased Odds of Infection Following Conversion Total Knee Arthroplasty.

BACKGROUND: The optimal timing of removal of periarticular implants prior to conversion total knee arthroplasty (TKA) remains to be determined. The purpose of this study was to compare infection rates in conversion TKA when hardware removal was performed in either a staged or concurrent manner. METHODS: We performed a retrospective study using a national insurance claims database of patients who underwent removal of hardware on the same day or within 1 year before their TKA. A total of 16,099 patients met the criteria. After matching, both final cohorts consisted of 4,502 patients. The 90-day and 1-year rates of prosthetic joint infection were calculated. RESULTS: The rates of infection were 1.64% and 3.00% in the staged group and 2.62% and 3.95% in the concurrent group at 90 days and 1 year postoperatively, respectively (P = .001, P = .01). Logistic regression analyses demonstrated that patients who had hardware removal greater than 3 months prior to TKA had significantly lower odds of infection at 1-year postop (Odds Ratio 0.61 95% Confidence Interval 0.45-0.84; P = .003). CONCLUSION: Removal of hardware performed concurrently or within 3 months of a TKA is associated with increased odds of prosthetic joint infection at 1 year postoperatively. Surgeons should consider removing periarticular hardware prior to TKA when possible.

A new approach for trace analysis of guanidine compounds in surface water with resorcinarene-based ion chromatography columns.

Trace levels of pharmaceuticals have been detected in surface water and may pose a health risk to humans and other organisms. New chromatographic materials will help identify and quantify these contaminants. We introduce a new ion chromatographic (IC) material designed to separate cationic pharmaceuticals and report its ability to separate a group of guanidine compounds. Guanidine moieties are strongly basic and protonated under acid conditions, and therefore can potentially be separated on the newly designed stationary phase and detected by ion exchange chromatography. The new column packing material is based on glutamic acids bonded to resorcinarene moieties that in turn are bound to divinylbenzene macroporous resin. Detection limits in the range of 5-30 µg L(-1) were achieved using integrated pulsed amperometric detection (IPAD) for guanidine (G), methylguanidine (MG), 1,1-dimethylbiguanide (DMG), agmatine (AGM), guanidinobenzoic acid (GBA) and cimetidine (CIM). Suppressed conductivity (CD) and UV-vis detection resulted in limits of detection similar to IPAD, in the range of 2-66 µg L(-1), but were not able to detect all of the analytes. Three water sources, river, lake, and marsh, were analyzed and despite matrix effects, sensitivity for guanidine compounds was in the 100 µg L(-1) range and apparent recoveries were 80-96%. The peak area precision was 0.01-2.89% for IPAD, CD and UV-vis detection.

Extent of coronary artery disease and outcomes after ticagrelor administration in patients with an acute coronary syndrome: Insights from the PLATelet inhibition and patient Outcomes (PLATO) trial.

BACKGROUND: Extensive coronary artery disease (CAD) is associated with higher risk. In this substudy of the PLATO trial, we examined the effects of randomized treatment on outcome events and safety in relation to the extent of CAD. METHODS: Patients were classified according to presence of extensive CAD (defined as 3-vessel disease, left main disease, or prior coronary artery bypass graft surgery). The trial's primary and secondary end points were compared using Cox proportional hazards regression. RESULTS: Among 15,388 study patients for whom the extent of CAD was known, 4,646 (30%) had extensive CAD. Patients with extensive CAD had more high-risk characteristics and experienced more clinical events during follow-up. They were less likely to undergo percutaneous coronary intervention (58% vs 79%, P < .001) but more likely to undergo coronary artery bypass graft surgery (16% vs 2%, P < .001). Ticagrelor, compared with clopidogrel, reduced the composite of cardiovascular death, myocardial infarction, and stroke in patients with extensive CAD (14.9% vs 17.6%, hazard ratio [HR] 0.85 [0.73-0.98]) similar to its reduction in those without extensive CAD (6.8% vs 8.0%, HR 0.85 [0.74-0.98], Pinteraction = .99). Major bleeding was similar with ticagrelor vs clopidogrel among patients with (25.7% vs 25.5%, HR 1.02 [0.90-1.15]) and without (7.3% vs 6.4%, HR 1.14 [0.98-1.33], Pinteraction = .24) extensive CAD. CONCLUSIONS: Patients with extensive CAD have higher rates of recurrent cardiovascular events and bleeding. Ticagrelor reduced ischemic events to a similar extent both in patients with and without extensive CAD, with bleeding rates similar to clopidogrel.

Complications and Learning Curve Associated with an Imageless Burr-Based (CORI) Robotic-Assisted Total Knee Arthroplasty System: Results from First 500 Cases.

Background: The use of robotic-assisted total knee arthroplasty (RA-TKA) is gaining traction. There is evidence to suggest that RA-TKA can help to optimize the precision and accuracy of implant positioning and that there may be protective effects on surrounding bony and soft tissues. Yet, there are important differences between the various RA-TKA systems currently on the market. One such newly introduced RA-TKA system uses imageless technology and performs bony cuts with the use of a burr-based device. The learning curve and complications unique to this system have yet to be assessed. Methods: We evaluated 500 consecutive RA-TKA cases using a newly developed burr-based and imageless system which were done by a single surgeon between the months of October 2021 and February 2023. Operative times were recorded and compared to the previous 150 conventional TKA cases allowing for the learning curve to be calculated using the CUSUM method. Intraoperative and postoperative complications were categorically profiled. Results: The learning curve of this RA-TKA system was found to be 6 cases. Intraoperative complications included unintended bony over resection (n = 3), soft tissue injury (n = 2), and robotic system hardware (n = 2) or software (n = 2) malfunction. Postoperative complications consisted of superficial pin site infection (n = 1) and periprosthetic fracture near the pin sites (n = 1). There were no identified cases of prosthetic joint infection, instability events, or wound complications. Conclusions: The learning curve and the complication profile of a newly introduced imageless and burr-based RA-TKA system were described. This information serves to guide surgeons in adopting this technology and can counsel them regarding the potential pitfalls and challenges associated with its integration into practice. The work sheds light on the complexity and learning curve of the recently released imageless burr-based RA-TKA system. This important information is intended to help surgeons accept this cutting-edge technology by providing advice on any errors and difficulties that can occur when integrating it into clinical practice. This information can help surgeons navigate the complexities of integrating this new burr-based robotic technology into knee replacement procedures, enabling them to make well-informed decisions and receive guidance.

Extracranial Vertebral Artery Injuries.

Paired vertebral arteries (VAs) travel from the subclavian artery through the cervical spine and into the intracranial space where they contribute to posterior cerebral circulation. Blunt and penetrating injuries to the cervical spine risk injury to the VA. Among the most feared complications of vertebral artery injury (VAI) is posterior circulation stroke. Appropriate screening and treatment of these injuries in the trauma setting remain vitally important to aid in the prevention of devastating neurologic sequelae. A robust knowledge of the VA anatomy is required for spine surgeons to avoid VAI during cervical spine approaches and instrumentation. Both anterior and posterior cervical spine surgeries can place the VA at risk. Careful preoperative assessment with the appropriate advanced imaging studies is necessary to verify the course of the VA in the cervical spine and thus prevent iatrogenic injury because anatomic variations along the course of the artery can prove hazardous if not properly anticipated. Iatrogenic VAI can be treated successfully with tamponade. However, in some cases, ligation, repair, or endovascular procedures may be indicated.

Effect of ticagrelor on the outcomes of patients with prior coronary artery bypass graft surgery: insights from the PLATelet inhibition and patient outcomes (PLATO) trial.

BACKGROUND: Patients with prior coronary artery bypass graft surgery (CABG) who present with an acute coronary syndrome have a high risk for recurrent events. Whether intensive antiplatelet therapy with ticagrelor might be beneficial compared with clopidogrel is unknown. In this substudy of the PLATO trial, we studied the effects of randomized treatment dependent on history of CABG. METHODS: Patients participating in PLATO were classified according to whether they had undergone prior CABG. The trial's primary and secondary end points were compared using Cox proportional hazards regression. RESULTS: Of the 18,613 study patients, 1,133 (6.1%) had prior CABG. Prior-CABG patients had more high-risk characteristics at study entry and a 2-fold increase in clinical events during follow-up, but less major bleeding. The primary end point (composite of cardiovascular death, myocardial infarction, and stroke) was reduced to a similar extent by ticagrelor among patients with (19.6% vs 21.4%; adjusted hazard ratio [HR], 0.91 [0.67, 1.24]) and without (9.2% vs 11.0%; adjusted HR, 0.86 [0.77, 0.96]; P(interaction) = .73) prior CABG. Major bleeding was similar with ticagrelor versus clopidogrel among patients with (8.1% vs 8.7%; adjusted HR, 0.89 [0.55, 1.47]) and without (11.8% vs 11.4%; HR, 1.08 [0.98, 1.20]; P(interaction) = .46) prior CABG. CONCLUSIONS: Prior-CABG patients presenting with acute coronary syndrome are a high-risk cohort for death and recurrent cardiovascular events but have a lower risk for major bleeding. Similar to the results in no-prior-CABG patients, ticagrelor was associated with a reduction in ischemic events without an increase in major bleeding.

Study design and rationale for the Stabilization of pLaques usIng Darapladib-Thrombolysis in Myocardial Infarction (SOLID-TIMI 52) trial in patients after an acute coronary syndrome.

BACKGROUND: Higher levels of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) are associated with a higher risk of cardiovascular events and may play a causal role in atherogenesis. Darapladib inhibits Lp-PLA(2) activity in plasma and in arterial plaques and may confer clinical benefit in preventing cardiovascular events. STUDY DESIGN: The SOLID-TIMI 52 trial is a randomized, double-blind, placebo-controlled, multicenter, event-driven trial. Approximately 13,000 subjects are being randomized to darapladib (160 mg enteric-coated tablet daily) or matching placebo within 30 days of hospitalization with an acute coronary syndrome. The primary end point is the composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. Secondary end points include major and total coronary events, individual components of the primary end point, and all-cause mortality. The study will continue until approximately 1,500 primary end point events have occurred to achieve 90% power to detect a 15.5% reduction in the primary end point. The median treatment duration is anticipated to be approximately 3 years, with a total study duration of approximately 4.1 years. CONCLUSIONS: The SOLID-TIMI 52 trial will determine the clinical benefit of direct inhibition of Lp-PLA(2) activity with darapladib in patients after an acute coronary syndrome.

The Modified 5-Item Frailty Index: A Concise and Useful Tool for Assessing the Impact of Frailty on Postoperative Morbidity Following Elective Posterior Lumbar Fusions.

BACKGROUND: The modified 5-item frailty index (mFI-5) is a concise comorbidity-based risk stratification tool that has been shown to predict the occurrence of adverse outcomes following various orthopedic surgeries. METHODS: The 2012-2016 American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP) dataset was used to identify patients undergoing an elective 1- to 2-level posterior lumbar fusion for degenerative lumbar pathology. The mFI-5 score was calculated based on the presence of the 5 co-morbidities: congestive heart failure within 30 days prior to surgery, insulin-dependent or noninsulin-dependent diabetes mellitus, chronic obstructive pulmonary disease or pneumonia, partially dependent or totally dependent functional health status at time of surgery, and hypertension requiring medication. Multivariate analysis was used to assess the independent impact of increasing mFI-5 score on postoperative morbidity while controlling for baseline clinical characteristics. RESULTS: Increasing mFI-5 score versus mFI-5 = 0 was associated with higher odds of any complication (mFI-5 ≥2: odds ratio [OR] 1.45; mFI-5 = 1: OR 1.22), 30-day readmissions (mFI-5 ≥2: OR 1.46; mFI-5 = 1: OR 1.18), and nonhome discharge (mFI-5 ≥2: OR 1.80; mFI-5 = 1: OR 1.16). Higher mFI-5 score was significantly associated with increased risks of superficial surgical site infection, deep surgical site infection, unplanned reoperation, any medical complication, pneumonia, unplanned intubation, postoperative ventilator use, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke, myocardial infarction, bleeding requiring transfusion, sepsis, and septic shock. CONCLUSIONS: Higher mFI-5 scores were associated with increased postoperative morbidity following elective 1- to 2-level posterior lumbar fusions.

Effect of ximelagatran on ischemic events and death in patients with atrial fibrillation after acute myocardial infarction in the efficacy and safety of the oral direct thrombin inhibitor ximelagatran in patients with recent myocardial damage (ESTEEM) trial.

BACKGROUND: New-onset trial fibrillation (AF) occurs commonly after acute myocardial infarction (MI) and is associated with a poor prognosis due to stroke or death. The optimal antithrombotic therapy is unknown. The aim of this study was to investigate whether an oral direct thrombin inhibitor, ximelagatran, added to aspirin, reduced the risk of death, myocardial infarction (MI), and stroke in patients who developed AF after their qualifying MI in the efficacy and safety of the oral direct thrombin inhibitor ximelagatran in patients with recent myocardial damage (ESTEEM) trial. METHODS: The ESTEEM trial evaluated 6 months treatment with ximelagatran together with aspirin, compared to aspirin alone, for prevention of ischemic events in 1883 patients randomized within 14 days after an MI. After their qualifying MI, 174 (9%) patients developed AF in hospital. Multivariate hazard ratios for ximelagatran compared with placebo were calculated by presence AF. RESULTS: Of 101 patients with AF treated with ximelagatran 7 (6.9%) had either death, MI, or stroke, compared with 15 (20.6%) in 73 patients allocated to placebo. Ximelagatran reduced the risk of death, MI, or stroke by 70% (hazard ratio 0.30, 95% CI 0.12-0.74). For the separate outcome events, we found similar, nonsignificant trends. One major bleeding event occurred in each treatment group. CONCLUSIONS: For patients with MI complicated by AF, the combination of aspirin and an oral direct thrombin inhibitor seems beneficial. The high risk for death, MI, and stroke in this population and the increasing use of percutaneous interventions in MI patients may suggest a combination of long-term antiplatelet and anticoagulant therapy. Randomized clinical trials are warranted.

Investigation of Air-Liquid Interface Rings in Buffer Preparation Vessels: the Role of Slip Agents.

Air-liquid interface rings were observed on the side walls of stainless steel buffer vessels after certain downstream buffer preparations. Those rings were resistant to regular cleaning-in-place procedures but could be removed by manual means. To investigate the root cause of this issue, multiple analytical techniques, including liquid chromatography with tandem mass spectrometry detection (LC-MS/MS), high-resolution accurate mass liquid chromatography with mass spectrometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy have been employed to characterize the chemical composition of air-liquid interface rings. The main component of air-liquid interface rings was determined to be slip agents, and the origin of the slip agents can be traced back to their presence on raw material packaging liners. Slip agents are commonly used in plastic industry as additives to reduce the coefficient of friction during the manufacturing process of thin films. To mitigate this air-liquid interface ring issue, an alternate liner with low slip agent was identified and implemented with minimal additional cost. We have also proactively tested the packaging liners of other raw materials currently used in our downstream buffer preparation to ensure slip agent levels are appropriate. LAY ABSTRACT: Air-liquid interface rings were observed on the side walls of stainless steel buffer vessels after certain downstream buffer preparations. To investigate the root cause of this issue, multiple analytical techniques have been employed to characterize the chemical composition of air-liquid interface rings. The main components of air-liquid interface rings were determined to be slip agents, which are common additives used in the manufacturing process of thin films. The origin of the slip agents can be traced back to their presence on certain raw material packaging liners. To mitigate this air-liquid interface ring issue, an alternate liner with low slip agent was identified and implemented.

Separation of uremic toxins from urine with resorcinarene-based ion chromatography columns.

People with chronic kidney disease suffer from uremic toxins which accumulate in their bodies. Detection and quantification of uremic toxins help diagnose kidney problems and start patient care. The aim of this research was to seek a new method to assist this diagnosis by trace level detection and separation of guanidine containing uremic toxins in water and urine. To detect and quantify the uremic toxins, new stationary phases for ion chromatography (IC) columns based on glutamic acid functionalized resorcinarenes bound to divinylbenzene macroporous resin were prepared. The new column packing material afforded separation of the five compounds: guanidinoacetic acid, guanidine, methylguanidine, creatinine, and guanidinobenzoic acid in 30min. Peak resolutions ranged from 7.6 to 1.3. Gradient elutions at ambient temperature with methanesulfonic acid (MSA) solution as eluent resulted in detection levels in water from 10 to 47ppb and in synthetic urine from 28 to 180ppb. Limits of quantification for the analytes using pulsed amperometric detection were 30-160ppb in water and 93-590ppb in urine. Trace levels of creatinine (1ppm) were detected in the urine of a healthy individual using the columns.

Risk of sudden versus nonsudden cardiac death in patients with coronary artery disease.

BACKGROUND: Patients at high risk of sudden cardiac death, yet at low risk of nonsudden death, might be ideal candidates for antiarrhythmic drugs or devices. Most previous studies of prognostic markers for sudden cardiac death have ignored the competitive risk of nonsudden cardiac death. The goal of the present study was to evaluate the ability of clinical factors to distinguish the risks of sudden and nonsudden cardiac death. METHODS: We identified all deaths during a 3.3-year follow-up of 30,680 patients discharged alive after admission to the cardiac care unit of a Seattle hospital. Detailed chart reviews were conducted on 1093 subsequent out-of-hospital sudden deaths, 973 nonsudden cardiac deaths, and 442 randomly selected control patients. RESULTS: Patients who died in follow-up (suddenly or nonsuddenly) were significantly different for many clinical factors from control patients. In contrast, patients with sudden cardiac death were insignificantly different for most clinical characteristics from patients with nonsudden cardiac death. The mode of death was 20% to 30% less likely to be sudden in women, patients who had angioplasty or bypass surgery, and patients prescribed beta-blockers. The mode of death was 20% to 30% more likely to be sudden in patients with heart failure, frequent ventricular ectopy, or a discharge diagnosis of acute myocardial infarction. A multivariable model had only modest predictive capacity for mode of death (c-index of 0.62). CONCLUSION: Standard clinical evaluation is much better at predicting overall risk of death than at predicting the mode of death as sudden or nonsudden.

A contemporary view of diagnostic cardiac catheterization and percutaneous coronary intervention in the United States: a report from the CathPCI Registry of the National Cardiovascular Data Registry, 2010 through June 2011.

OBJECTIVES: This study sought to provide a report to the public of data from the CathPCI Registry of the National Cardiovascular Data Registry. BACKGROUND: The CathPCI Registry collects data from approximately 85% of the cardiac catheterization laboratories in the United States. METHODS: Data were summarized for 6 consecutive calendar quarters beginning January 1, 2010, and ending June 30, 2011. This report includes 1,110,150 patients undergoing only diagnostic cardiac catheterization and 941,248 undergoing percutaneous coronary intervention (PCI). RESULTS: Some notable findings include, for example, that on-site cardiac surgery was not available in 83% of facilities performing fewer than 200 PCIs annually, with these facilities representing 32.6% of the facilities reporting, but performing only 12.4% of the PCIs in this data sample. Patients 65 years of age or older represented 38.7% of those undergoing PCI, with 12.3% being 80 years of age or older. Almost 80% of PCI patients were overweight (body mass index ≥25 kg/m(2)), 80% had dyslipidemia, and 27.6% were current or recent smokers. Among patients undergoing elective PCI, 52% underwent a stress study before the procedure, with stress myocardial perfusion being used most frequently. Calcium scores and coronary computed tomography angiography were used very infrequently (<3%) before diagnostic or PCI procedures. Radial artery access was used in 8.3% of diagnostic and 6.9% of PCI procedures. Primary PCI was performed with a median door-to-balloon time of 64.5 min for nontransfer patients and 121 min for transfer patients. In-hospital risk-adjusted mortality in ST-segment elevation myocardial infarction patients was 5.2% in this sample. CONCLUSIONS: Data from the CathPCI Registry provide a contemporary view of the current practice of invasive cardiology in the United States.

Vascular catheters with a nonleaching poly-sulfobetaine surface modification reduce thrombus formation and microbial attachment.

Adherence of proteins, cells, and microorganisms to the surface of venous catheters contributes to catheter occlusion, venous thrombosis, thrombotic embolism, and infections. These complications lengthen hospital stays and increase patient morbidity and mortality. Current technologies for inhibiting these complications are limited in duration of efficacy and may induce adverse side effects. To prevent complications over the life span of a device without using active drugs, we modified a catheter with the nonleaching polymeric sulfobetaine (polySB), which coordinates water molecules to the catheter surface. The modified surface effectively reduced protein, mammalian cell, and microbial attachment in vitro and in vivo. Relative to commercial catheters, polySB-modified catheters exposed to human blood in vitro had a >98% reduction in the attachment and a significant reduction in activation of platelets, lymphocytes, monocytes, and neutrophils. Additionally, the accumulation of thrombotic material on the catheter surface was reduced by >99% even after catheters were exposed to serum in vitro for 60 days. In vivo, in a highly thrombogenic canine model, device- and vessel-associated thrombus was reduced by 99%. In vitro adherence of a broad spectrum of microorganisms was reduced on both the external and the internal surfaces of polySB-modified catheters compared to unmodified catheters. When unmodified and polySB-modified catheters were exposed to the same bacterial challenge and implanted into animals, 50% less inflammation and fewer bacteria were associated with polySB-modified catheters. This nonleaching, polySB-modified catheter could have a major impact on reducing thrombosis and infection, thus improving patient health.