Development of an Integrated Powered Hip and Microprocessor-Controlled Knee for a Hip-Knee-Ankle-Foot Prosthesis.

Hip-knee-ankle-foot prostheses (HKAF) are full lower-limb devices for people with hip amputations that enable individuals to regain their mobility and move freely within their chosen environment. HKAFs typically have high rejection rates among users, as well as gait asymmetry, increased trunk anterior-posterior lean, and increased pelvic tilt. A novel integrated hip-knee (IHK) unit was designed and evaluated to address the limitations of existing solutions. This IHK combines powered hip and microprocessor-controlled knee joints into one structure, with shared electronics, sensors, and batteries. The unit is also adjustable to user leg length and alignment. ISO-10328:2016 standard mechanical proof load testing demonstrated acceptable structural safety and rigidity. Successful functional testing involved three able-bodied participants walking with the IHK in a hip prosthesis simulator. Hip, knee, and pelvic tilt angles were recorded and stride parameters were analyzed from video recordings. Participants were able to walk independently using the IHK and data showed that participants used different walking strategies. Future development of the thigh unit should include completion of a synergistic gait control system, improved battery-holding mechanism, and amputee user testing.

Race and outcomes after percutaneous coronary intervention: Insights from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium.

BACKGROUND: Current studies show similar in-hospital outcomes following percutaneous coronary intervention (PCI) between Black and White patients. Long-term outcomes and the role of individual and community-level socioeconomic factors in differential risk are less understood. METHODS: We linked clinical registry data from PCIs performed between January, 2013 and March, 2018 at 48 Michigan hospitals to Medicare Fee-for-service claims. We analyzed patients of Black and White race. We used propensity score matching and logistic regression models to estimate the odds of 90-day readmission and Cox regression to evaluate the risk of postdischarge mortality. We used mediation analysis to evaluate the proportion of association mediated by socioeconomic factors. RESULTS: Of the 29,317 patients included in this study, 10.28% were Black and 89.72% were White. There were minimal differences between groups regarding post-PCI in-hospital outcomes. Compared with White patients, Black patients were more likely to be readmitted within 90-days of discharge (adjusted OR 1.62, 95% CI [1.32-2.00]) and had significantly higher risk of all-cause mortality (adjusted HR 1.45, 95% CI 1.30-1.61) when adjusting for age and gender. These associations were significantly mediated by dual eligibility (proportion mediated [PM] for readmission: 11.0%; mortality: 21.1%); dual eligibility and economic well-being of the patient's community (PM for readmission: 22.3%; mortality: 43.0%); and dual eligibility, economic well-being of the community, and baseline clinical characteristics (PM for readmission: 45.0%; mortality: 87.8%). CONCLUSIONS: Black patients had a higher risk of 90-day readmission and cumulative mortality following PCI compared with White patients. Associations were mediated by dual eligibility, community economic well-being, and traditional cardiovascular risk factors. Our study highlights the need for improved upstream care and streamlined postdischarge care pathways as potential strategies to improve health care disparities in cardiovascular disease.

Design and validation of an automated dual-arm instrumented intravaginal dynamometer.

AIMS: (1) To present the design of a novel intravaginal dynamometer (IVD) capable of measuring vaginal closure force on both the anterior and posterior arms, (2) to use bench testing to validate the force, speed of arm opening, and positional accuracy of load measurement along the IVD arms, and (3) to present in vivo force measurements made with this device, comparing forces measured by the anterior and posterior arms. METHODS: IVD load measurements were validated against an Instron® Universal Tester, arm opening speeds were validated using video analysis, and position-load accuracy was validated against calibration weights. In vivo IVD data were acquired from female volunteers during passive opening and pelvic floor muscle contraction tasks. Anterior and posterior IVD arm force outcomes were compared. RESULTS: Forces measured by the IVD and Instron® exhibited a strong linear relationship with excellent model fit. The speed control system was valid when tested under physiological loading conditions, however smaller antero-posterior opening diameters (25 and 30 mm) exhibited some error. The loading position along the IVD arms had no effect on force outcomes. In vivo data exhibited differences between force outcomes measured at the anterior and posterior aspects of the vagina during active contraction and passive elongation of the pelvic floor muscles. CONCLUSIONS: This IVD design demonstrates valid load measurement and speed control during bench testing. Active and passive forces measured are consistent with the literature. With dual instrumented arms, this device allows for further investigation into the source of measured vaginal closure forces.

Charge-Separated and Lewis Paired Metal-Organic Framework for Anion Exchange and CO2 Chemical Fixation.

Charge-separated metal-organic frameworks (MOFs) are a unique class of MOFs that can possess added properties originating from the exposed ionic species. A new charge-separated MOF, namely, UNM-6 synthesized from a tetrahedral borate ligand and Co2+ cation is reported herein. UNM-6 crystalizes into the highly symmetric P43n space group with fourfold interpenetration, despite the stoichiometric imbalance between the B and Co atoms, which also leads to loosely bound NO3 - anions within the crystal structure. These NO3 - ions can be quantitatively exchanged with various other anions, leading to Lewis acid (Co2+ ) and Lewis base (anions) pairs within the pores and potentially cooperative catalytic activities. For example, UNM-6-Br, the MOF after anion exchange with Br- anions, displays high catalytic activity and stability in reactions of CO2 chemical fixation into cyclic carbonates.

Appropriate Use of Transesophageal Echocardiogram for Infective Endocarditis: A Single Center Experience.

BACKGROUND: Transesophageal echocardiogram (TEE) is a valuable tool in healthcare today with its ease of use, ability to visualize important structures not seen on transthoracic echocardiogram (TTE), and the relatively lower cost of TEE, high yield, and no significant radiation exposure. The American Society of Echocardiography (ASE) has developed an appropriate use criteria for use of TTE and TEE, which outline various scenarios where a TEE is indicated as an initial diagnostic testing modality and when it is useful as an adjunctive test in hopes of decreasing inappropriate use. Using these criteria as a guide, we devised a quality assessment study to investigate how well TEEs performed at our institution fit the appropriate use criteria specifically for the diagnostic workup of infective endocarditis. METHODS: A retrospective chart review was performed for all TEEs performed in 2017 with the indication of endocarditis. Baseline patient characteristics, presence of bacteremia, and the quality of the TTE preceding the TEE were noted, as well as whether a vegetation, abscess, or perforation was visualized. We also determined if there was a cardiology consultation placed prior to TEE and if the patient had met the definition for endocarditis as defined by the Duke criteria. Finally, we made note of the TEE findings and assessed whether the TEE met appropriate use criteria developed by the American Society of Echocardiography. RESULTS: A total of 50 patients who underwent TEE with the indication of "endocarditis" were identified. 36% of the TTEs prior to the TEE were rated as good quality, 40% as adequate, 4% as fair, 4% as suboptimal, 12% as technically difficult, and 4% were not rated. Vegetations were visualized on 12% of TTEs, 6% of patients had a prosthetic valve, and 6% had a cardiac device. In 20% of the cases, there was no cardiology consultation prior to the TEE and in 20% of the cases, there was no documented bacteremia. 26% of patients met the Duke criteria for endocarditis prior to TEE. Only 36% of TEEs revealed evidence of infection and of the patients with no evidence of infection, only 38% met appropriate use criteria. Overall, only 56% of patients met appropriate use criteria for TEE. CONCLUSION: Transesophageal echocardiography is a valuable tool in a modern physician's arsenal for managing a variety of diseases and conditions. However, the procedure is not without associated risks and its ease of use and widespread adoption has led to frequent questionable appropriateness of use of the test. Only 56% of the TEEs performed in our analysis met appropriate use. More awareness and education is needed for the appropriate use criteria for transesophageal echocardiography as outlined by the ASE to help reduce patient exposure to procedure related complications and to decrease medical costs on unnecessary procedures.

The role of acute circulatory support in ST-segment elevation myocardial infarction complicated by cardiogenic shock.

In the setting of ST-segment elevation myocardial infarction (STEMI) complicated by cardiogenic shock, three primary treatment objectives include providing circulatory support, ventricular unloading, and restoring myocardial perfusion. In addition to primary percutaneous coronary intervention, each of these three objectives can be achieved with appropriate use of an acute mechanical circulatory support (AMCS) pump. Over the past decade, utilization of percutaneously-delivered AMCS devices including the Impella axial-flow catheter, TandemHeart left atrial-to-femoral artery bypass system, and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has grown exponentially. In this review, we will discuss the hemodynamic impact of each AMCS device and clinical data surrounding their use in the setting of STEMI complicated by cardiogenic shock.

Mechanical Circulatory Support Devices for Acute Right Ventricular Failure.

Right ventricular (RV) failure remains a major cause of global morbidity and mortality for patients with advanced heart failure, pulmonary hypertension, or acute myocardial infarction and after major cardiac surgery. Over the past 2 decades, percutaneously delivered acute mechanical circulatory support pumps specifically designed to support RV failure have been introduced into clinical practice. RV acute mechanical circulatory support now represents an important step in the management of RV failure and provides an opportunity to rapidly stabilize patients with cardiogenic shock involving the RV. As experience with RV devices grows, their role as mechanical therapies for RV failure will depend less on the technical ability to place the device and more on improved algorithms for identifying RV failure, patient monitoring, and weaning protocols for both isolated RV failure and biventricular failure. In this review, we discuss the pathophysiology of acute RV failure and both the mechanism of action and clinical data exploring the utility of existing RV acute mechanical circulatory support devices.

Ablation or surgery for medically refractory HCM. Updating an imperfect dataset.

Retrospective comparison of alcohol septal ablation with surgical myectomy suggests that although there is a greater reduction in LVOT gradient with surgical myectomy, symptom relief and survival are similar between the two treatment strategies. In patients who don't have an anatomic indication for surgical myectomy, alcohol septal ablation appears to be a safe and effective alternative. Patients with medication-refractory HOCM require a multi-disciplinary assessment, which is best performed at specialized treatment centers, to assess which therapy is best suited to treat them.

Subcutaneous Implantable Cardioverter Defibrillator in Patients With Hypertrophic Cardiomyopathy: An Initial Experience.

BACKGROUND: The subcutaneous implantable cardioverter defibrillator (S-ICD) has been developed to avert risks associated with transvenous defibrillator leads. The technology is attractive for younger patients, such as those with hypertrophic cardiomyopathy (HCM). However, there are limited data on S-ICD use in HCM. METHODS AND RESULTS: HCM patients identified at risk for sudden death were considered for S-ICD implantation. Patients were screened for potential oversensing by surface electrocardiography (ECG). At implant, defibrillation threshold (DFT) testing was performed at 65, 50, and 35 joules (J). Twenty-seven patients were considered for S-ICD implantation, and after screening, 23 (85%) remained eligible. The presence of a bundle branch block was associated with screening failure, whereas elevated body mass index (BMI) showed a trend toward association. One patient passed screening at rest, but failed with an ECG obtained after exercise. At implant, the S-ICD terminated ventricular fibrillation (VF) with a 65J shock in all 15 implanted patients and a 50J shock was successful in 12 of 15. A 35J shock terminated VF in 10 of 12 patients. DFT failure at 50 J was associated with a higher BMI. There were no appropriate shocks after a median follow-up of 17.5 (3-35) months, and 1 patient received an inappropriate shock attributable to a temporary reduction in QRS amplitude while bending forward, resulting in oversensing, despite successful screening. CONCLUSIONS: In a high-risk HCM cohort without a pacing indication referred for consideration of an ICD, the majority were eligible for S-ICD. The S-ICD is effective at recognizing and terminating VF at implant with a wide safety margin.

Percutaneous Circulatory Assist Devices for Right Ventricular Failure.

Heart failure is a major cause of global morbidity and mortality affecting nearly 24 million individuals worldwide. Although the importance of right ventricular (RV) function has become more apparent over the past few decades, few therapies specifically target RV failure. Over the past 3 decades, significant advances in percutaneously delivered circulatory support devices has led to the recent development of devices specifically designed for RV failure. In this review, RV pathophysiology, device options, and clinical data exploring the utility of percutaneous RV support devices are discussed.

Internet diagnosis of digitalis toxicity.

A 65-year-old male with an ischaemic cardiomyopathy and an implantable cardioverter defibrillator got a shock at home. A web-based monitoring system was used to check his device, and the interrogation showed that he had had several episodes of ventricular fibrillation and new onset of complete heart block that required back-up pacing by his defibrillator. The combination of enhanced automaticity (frequent premature ventricular complexes and ventricular arrhythmias) and impaired conduction (heart block) are the hallmarks of digitalis toxicity. Paramedics were called and the patient was brought to the emergency room where he was confirmed to have digitalis toxicity and was quickly treated with digoxin-specific Fab antibody fragments. Web-based monitoring systems helped in the diagnosis of this potentially lethal drug toxicity.