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1.
Liver Transpl ; 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38900010

ABSTRACT

BACKGROUND & AIMS: Physical frailty is a critical determinant of mortality in patients with cirrhosis and can be objectively measured using the Liver Frailty Index (LFI) that is potentially modifiable.. We aimed to LFI cut-points associated with waitlist mortality. APPROACH & RESULTS: Ambulatory adults with cirrhosis without HCC awaiting liver transplantation (LT) from 9 centers from 2012-2021 for ≥3 months with ≥2 pre-LT LFI assessments were included. The primary explanatory variable was change in LFI from first to second assessments per 3 months (∆LFI); we evaluated clinically-relevant ∆LFI cut-points at 0.1, 0.2, 0.3, and 0.5. The primary outcome was waitlist mortality (death or delisting for being too sick) with transplant considered as a competing event. Among 1029 patients, median (IQR) age was 58 (51-63) years; 42% were female; and median lab MELDNa at first assessment was 18 (15-22). For each 0.1 improvement in ∆LFI, risk of overall mortality decreased by 6% (cause-specific hazard ratio [cHR] 0.94, 95%CI 0.92-0.97, p < 0.001). ∆LFI was associated with waitlist mortality at cut-points as low as 0.1 (cHR 0.63, 95%CI 0.46-0.87) and 0.2 (HR 0.61, 95%CI 0.42-0.87). CONCLUSIONS: An improvement in LFI per 3 months as small as 0.1 in the pre-LT period is associated with a clinically meaningful reduction in waitlist mortality. These data provide estimates of the reduction in mortality risk associated with improvements in LFI that can be used to assess effectiveness of interventions targeting physical frailty in cirrhosis patients.

2.
Clin Transplant ; 38(1): e15232, 2024 01.
Article in English | MEDLINE | ID: mdl-38289890

ABSTRACT

INTRODUCTION: Cognitive impairment (CI) among liver transplant (LT) candidates is associated with increased risk of waitlist mortality and inferior outcomes. While formal neurocognitive evaluation is the gold standard for CI diagnosis, the Montreal Cognitive Assessment (MoCA) is often used for first-line cognitive screening. However, MoCA requires specialized training and may be too lengthy for a busy evaluation appointment. An alternate approach may be the Quick Dementia Rating System (QDRS), which is patient- and informant-based and can be administered quickly. We compared potential LT candidates identified by MoCA and QDRS as potentially benefiting from further formal cognitive evaluation. METHODS: We identified 46 potential LT candidates enrolled at a single center of a prospective, observational cohort study who were administered MoCA and QDRS during transplant evaluation (12/2021-12/2022). Scores were dichotomized as (1) normal versus abnormal and (2) normal/mild impairment versus more-than-mild impairment. We calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of QDRS compared to MoCA. RESULTS: By MoCA, this population had a prevalence of 48% normal cognition, 48% mild, 4% moderate, and 0% severe impairment. This was categorized as 96% normal/mild and 4% more-than-mild impairment. When comparing to MoCA cognitive screening, QDRS had a sensitivity of 61%, specificity of 56%, NPV of 56%, and PPV of 61%. When identifying more-than-mild impairment, QDRS had a sensitivity of 100%, specificity of 73%, NPV of 100%, and PPV of 10%. CONCLUSION: The high sensitivity and NPV of QDRS in identifying more-than-mild impairment suggests it could identify potential LT candidates who would benefit from further formal cognitive evaluation. The ability to administer QDRS quickly and remotely makes it a pragmatic option for pre-transplant screening.


Subject(s)
Cognitive Dysfunction , Liver Transplantation , Humans , Liver Transplantation/adverse effects , Prospective Studies , Sensitivity and Specificity , Neuropsychological Tests , Cognitive Dysfunction/diagnosis , Cognitive Dysfunction/etiology
3.
Clin Transplant ; 38(1): e15205, 2024 01.
Article in English | MEDLINE | ID: mdl-38041450

ABSTRACT

BACKGROUND: Patients with obesity have inferior outcomes after general surgery procedures, but studies evaluating post-liver transplant (LT) outcomes have been limited by small sample sizes or lack of granularity of outcomes. We evaluated the relationship between obesity and post-LT outcomes, including those observed in other populations to be obesity-related. METHODS: Included were 1357 LT recipients prospectively enrolled in the ambulatory pre-LT setting at 8 U.S. CENTERS: Recipient were categorized by body mass index (BMI, kg/m2 ): non-obese (BMI < 30), class 1 obesity (BMI 30-<35), and classes 2-3 obesity (BMI ≥ 35). Post-transplant complications were compared by BMI using Chi-square and rank-sum testing, logistic regression, Kaplan-Meier curves, and Cox regression. RESULTS: Classes 2-3 obesity was associated with higher adjusted odds than non-obesity of venous thrombosis [adjusted odds ratio (aOR) 2.06, 95% CI 1.01-4.23, p = .047] and wound dehiscence (aOR 2.45, 95% CI 1.19-5.06, p = .02). Compared with non-obese recipients, post-LT hospital stay was significantly longer for recipients with classes 2-3 obesity [p = .01; median (Q1-Q3) 9 (6-14) vs. 8 (6-12) days) or class 1 obesity [p = .002; 9 (6-14) vs. 8 (6-11) days].  Likelihood of ICU readmission, infection, discharge to a non-home facility, rejection, 30-day readmission, and 1-year readmission were similar across BMI categories (all p > .05). CONCLUSION: Compared to non-obese recipients, obese recipients had similar post-LT survival but longer hospital stay and higher likelihood of wound dehiscence and venous thrombosis. These findings underscore that obesity alone should not preclude LT, but recipients with obesity should be monitored for obesity-related complications such as wound dehiscence and venous thrombosis.


Subject(s)
Liver Transplantation , Venous Thrombosis , Humans , Body Mass Index , Liver Transplantation/adverse effects , Obesity/etiology , Postoperative Complications/etiology , Venous Thrombosis/complications , Retrospective Studies , Treatment Outcome , Risk Factors
4.
Radiology ; 306(3): e212403, 2023 03.
Article in English | MEDLINE | ID: mdl-36283115

ABSTRACT

Background Pre-liver transplant (LT) sarcopenia is associated with poor survival. Methods exist for measuring body composition with use of CT scans; however, it is unclear which components best predict post-LT outcomes. Purpose To quantify the association between abdominal CT-based body composition measurements and post-LT mortality in a large North American cohort. Materials and Methods This was a retrospective cohort of adult first-time deceased-donor LT recipients from 2009 to 2018 who underwent pre-LT abdominal CT scans, including at the L3 vertebral level, at Johns Hopkins Hospital. Measurements included sarcopenia (skeletal muscle index [SMI] <50 in men and <39 in women), sarcopenic obesity, myosteatosis (skeletal muscle CT attenuation <41 mean HU for body mass index [BMI] <25 and <33 mean HU for BMI ≥25), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and VAT/SAT ratio. Covariates in the adjusted models were selected with use of least absolute shrinkage and selection operator regression with lambda chosen by means of 10-fold cross-validation. Cox proportional hazards models were used to quantify associations with post-LT mortality. Model discrimination was quantified using the Harrell C-statistic. Results A total of 454 recipients (median age, 57 years [IQR, 50-62 years]; 294 men) were evaluated. In the adjusted model, pre-LT sarcopenia was associated with a higher hazard ratio (HR) of post-LT mortality (HR, 1.6 [95% CI: 1.1, 2.4]; C-statistic, 0.64; P = .02). SMI was significantly negatively associated with survival after adjustment for covariates. There was no evidence that myosteatosis was associated with mortality (HR, 1.3 [95% CI: 0.86, 2.1]; C-statistic, 0.64; P = .21). There was no evidence that BMI (HR, 1.2 [95% CI: 0.95, 1.4]), VAT (HR, 1.0 [95% CI: 0.98, 1.1]), SAT (HR, 1.0 [95% CI: 0.97, 1.0]), and VAT/SAT ratio (HR, 1.1 [95% CI: 0.90, 1.4]) were associated with mortality (P = .15-.77). Conclusions Sarcopenia, as assessed on routine pre-liver transplant (LT) abdominal CT scans, was the only factor significantly associated with post-LT mortality. © RSNA, 2022 See also the editorial by Ruehm in this issue.


Subject(s)
Liver Transplantation , Sarcopenia , Adult , Male , Humans , Female , Middle Aged , Sarcopenia/complications , Sarcopenia/diagnostic imaging , Retrospective Studies , Living Donors , Body Composition , Muscle, Skeletal , Tomography, X-Ray Computed/methods
5.
Chembiochem ; 24(23): e202300565, 2023 12 01.
Article in English | MEDLINE | ID: mdl-37737964

ABSTRACT

Proteins represent powerful biomacromolecules due to their unique functionality and broad utility both in the cell and in non-biological applications. The genetic encoding of non-canonical amino acids (ncAAs) facilitates functional diversification of these already powerful proteins. Specifically, ncAAs have been demonstrated to provide unique functional handles to bioorthogonally introduce novel functionality via conjugation reactions. Herein we examine the ability of a single ncAA to serve as a handle to generate multivalent bioconjugates to introduce two or more additional components to a protein, yielding a multivalent conjugate. To accomplish this aim, p-bromopropargyloxyphenyalanine (pBrPrF) was genetically encoded into both superfolder green fluorescent protein (sfGFP) and ubiquitin model proteins to serve as a conjugation handle. A sequential bioconjugation sequence involving a copper-assisted cycloaddition reaction coupled with a subsequent Sonogashira cross-coupling was then optimized. The linkage of two additional molecules to the model protein via these reactions yielded the desired multivalent bioconjugate. This domino approach using a single ncAA has a plethora of applications in both therapeutics and diagnostics as multiple unique moieties can be introduced into proteins in a highly controlled fashion.


Subject(s)
Amino Acids , Amino Acids/chemistry , Green Fluorescent Proteins/chemistry
6.
Am J Transplant ; 22(1): 274-278, 2022 01.
Article in English | MEDLINE | ID: mdl-34487636

ABSTRACT

Status 1A liver transplant candidates are given the highest medical priority for the allocation of deceased donor livers. Organ Procurement and Transplantation Network (OPTN) policy requires physicians to certify that a candidate has a life expectancy without a transplant of less than 7 days for that candidate to be given status 1A. Additionally, candidates receiving status 1A must have one of six medical conditions listed in policy. Using Scientific Registry of Transplant Recipients data from all prevalent liver transplant candidates from 2010 to 2020, we used a bias-corrected Kaplan-Meier model to calculate the survival of status 1A candidates and to determine their life expectancy without a transplant. We found that status 1A candidates have a life expectancy without a transplant of 24 (95% CI 20-46) days-over three times longer than what policy requires for status 1A designation. We repeated the analysis for subgroups of status 1A candidates based on the medical conditions that grant status 1A. We found that none of these subgroups met the life expectancy requirement. Harmonizing OPTN policy with observed data would sustain the integrity of the allocation process.


Subject(s)
Heart Transplantation , Liver Transplantation , Tissue and Organ Procurement , Humans , Life Expectancy , Waiting Lists
7.
Am J Transplant ; 22(4): 1145-1157, 2022 04.
Article in English | MEDLINE | ID: mdl-34953170

ABSTRACT

Kidney transplantation (KT) experts did not support the use of subjective unintentional weight loss to measure shrinking in the physical frailty phenotype (PFP); a clinically feasible and predictive measure of shrinking is needed. To test whether unintentional weight loss could be replaced by an assessment of sarcopenia using existing CT scans, we performed a prospective cohort study of adult KT recipients with original PFP (oPFP) measured at admission (December 2008-February 2020). We ascertained sarcopenia by calculating skeletal muscle index from available, clinically obtained CTs within 1-year pre-KT (male < 50 cm2 /m2 ; female < 39 cm2 /m2 ) and combined it with the original four components to determine new PFP (nPFP) scores. Frailty was classified by frailty score: 0: non-frail; 1-2: pre-frail; ≥3: frail. Mortality and graft loss hazard ratios (HRs) were estimated using adjusted Cox proportional hazard models. Model discrimination was quantified using Harrell's C-statistic. Among 1113 recipients, 18.6% and 17.1% were frail by oPFP and nPFP, respectively. Compared to non-frail recipients, frail patients by either PFP had higher risks of mortality (oPFP HR = 1.67, 95% CI: 1.07-2.62, C = 0.710; nPFP HR = 1.68, 95% CI: 1.06-2.66, C = 0.710) and graft loss (oPFP HR = 1.67, 95% CI: 1.17-2.40, C = 0.631; nPFP HR = 1.66, 95% CI: 1.15-2.40, C = 0.634) with similar discriminations. oPFP and nPFP are equally useful in risk prediction for KT recipients; oPFP may aid in screening patients for pre-KT interventions, while nPFP may assist in nuanced clinical decision-making.


Subject(s)
Frailty , Kidney Failure, Chronic , Kidney Transplantation , Sarcopenia , Aged , Female , Frail Elderly , Frailty/diagnosis , Humans , Kidney Transplantation/adverse effects , Male , Phenotype , Prospective Studies , Risk Factors , Sarcopenia/diagnostic imaging , Sarcopenia/etiology , Tomography, X-Ray Computed , Transplant Recipients , Weight Loss
8.
Liver Transpl ; 28(6): 969-982, 2022 06.
Article in English | MEDLINE | ID: mdl-34923725

ABSTRACT

Patient and graft survival are similar following whole-liver transplantations (WLTs) versus split-liver transplantations (SLTs) among pediatric and adult recipients, yet SLTs are rarely used. We sought to determine the survival benefit associated with accepting a splittable graft offer for SLT versus declining and waiting for a subsequent offer using 2010 to 2018 Scientific Registry of Transplant Recipients (SRTR) data on 928 pediatric and 1814 adult liver transplantation candidates who were ever offered a splittable graft. We compared eventual mortality, regardless of subsequent transplants, between those patients who accepted versus declined a split liver offer with adjustments for Pediatric End-Stage Liver Disease/Model for End-Stage Liver Disease (MELD) scores, diagnosis, and weight among pediatric candidates and matching for MELD score, height, and offer among adult candidates. Among pediatric candidates ≤7 kg, split liver offer acceptance versus decline was associated with a 63% reduction in mortality (adjusted hazard ratio [aHR], 0.17 0.370.80 [P = 0.01]; 93.1% versus 84.0% 1-year survival after decision). Within 1 year of decline for those ≤7 kg, 6.4% died and 31.1% received a WLT. Among pediatric candidates >7 kg, there was no significant difference associated with acceptance of a split liver offer (aHR, 0.63 1.071.82 [P = 0.81]; 91.7% versus 94.4% 1-year survival after decision). Within 1 year of decline for those >7 kg, 1.8% died and 45.8% received a WLT. Among adult candidates, split liver offer acceptance was associated with a 43% reduction in mortality (aHR, 0.39 0.570.83 [P = 0.005]; 92.2% versus 84.4% 1-year survival after decision). Within 1 year of decline for adult candidates, 7.9% died and 39.3% received a WLT. Accepting split liver offers for SLT could significantly improve survival for small children and adults on the waiting list.


Subject(s)
End Stage Liver Disease , Liver Transplantation , Adult , Child , End Stage Liver Disease/diagnosis , End Stage Liver Disease/surgery , Graft Survival , Humans , Liver Transplantation/adverse effects , Severity of Illness Index , Waiting Lists
9.
BMC Geriatr ; 22(1): 566, 2022 07 08.
Article in English | MEDLINE | ID: mdl-35804289

ABSTRACT

BACKGROUND: Among adult kidney transplant (KT) candidates, 21% are frail and 55% have cognitive impairment, increasing the risk of pre- and post-KT mortality. Centers often assess frailty status and cognitive function during transplant evaluation to help identify appropriate candidate. Yet, there are no ethical guidelines regarding the use of frailty and cognitive function during this evaluation. We seek to develop a clinical consensus on balancing utility and justice in access to KT for frail and cognitively impaired patients. METHODS: Twenty-seven experts caring for ESRD patients completed a two-round Delphi panel designed to facilitate consensus (> 80% agreement). RESULTS: Experts believed that denying patients transplantation based solely on expected patient survival was inequitable to frail or cognitively impaired candidates; 100% agreed that frailty and cognitive impairment are important factors to consider during KT evaluation. There was consensus that health related quality of life and social support are important to consider before waitlisting frail or cognitively impaired patients. Experts identified important factors to consider before waitlisting frail (likely to benefit from KT, frailty reversibility, age, and medical contraindications) and cognitively impaired (degree of impairment and medication adherence) patients. CONCLUSIONS: Clinical experts believed it was ethically unacceptable to allocate organs solely based on patients' expected survival; frailty and cognitive impairment should be measured at evaluation when weighed against other clinical factors. Ethical guidelines regarding the use of frailty and cognitive function during KT evaluation ought to be developed.


Subject(s)
Cognitive Dysfunction , Frailty , Kidney Transplantation , Aged , Cognitive Dysfunction/diagnosis , Cognitive Dysfunction/therapy , Delphi Technique , Frail Elderly/psychology , Frailty/diagnosis , Frailty/therapy , Humans , Quality of Life
10.
BMC Geriatr ; 22(1): 82, 2022 01 27.
Article in English | MEDLINE | ID: mdl-35086480

ABSTRACT

BACKGROUND: Frailty predicts adverse post-kidney transplant (KT) outcomes, yet the impact of frailty assessment on center-level outcomes remains unclear. We sought to test whether transplant centers assessing frailty as part of clinical practice have better pre- and post-KT outcomes in all adult patients (≥18 years) and older patients (≥65 years). METHODS: In a survey of US transplant centers (11/2017-4/2018), 132 (response rate = 65.3%) centers reported their frailty assessment practices (frequency and specific tool) at KT evaluation and admission. Assessment frequency was categorized as never, sometime, and always; type of assessment tool was categorized as none, validated (for post-KT risk prediction), and any other tool. Center characteristics and clinical outcomes for adult patients during 2017-2019 were gleaned from the transplant national registry (Scientific Registry of Transplant Recipients). Poisson regression was used to estimate incidence rate ratios (IRRs) of waitlist outcomes (waitlist mortality, transplantation) in candidates and IRRs of post-KT outcomes (all-cause mortality, death-censored graft loss) in recipients by frailty assessment frequency. We also estimated IRRs of waitlist outcomes by type of assessment tool at evaluation. All models were adjusted for case mix and center characteristics. RESULTS: Assessing frailty at evaluation was associated with lower waitlist mortality rate (always IRR = 0.91,95%CI:0.84-0.99; sometimes = 0.89,95%CI:0.83-0.96) and KT rate (always = 0.94,95%CI:0.91-0.97; sometimes = 0.88,95%CI:0.85-0.90); the associations with waitlist mortality rate (always = 0.86,95%CI:0.74-0.99; sometimes = 0.83,95%CI:0.73-0.94) and KT rate (always = 0.82,95%CI:0.77-0.88; sometimes = 0.92,95%CI:0.87-0.98) were stronger in older patients. Furthermore, using validated (IRR = 0.90,95%CI:0.88-0.92) or any other tool (IRR = 0.90,95%CI:0.87-0.93) at evaluation was associated lower KT rate, while only using a validated tool was associated with lower waitlist mortality rate (IRR = 0.89,95%CI:0.83-0.96), especially in older patients (IRR = 0.82,95%CI:0.72-0.93). At admission for KT, always assessing frailty was associated with a lower graft loss rate (IRR = 0.71,95%CI:0.54-0.92) but not with mortality (IRR = 0.93,95%CI:0.76-1.13). CONCLUSIONS: Assessing frailty at evaluation is associated with lower KT rate, while only using a validated frailty assessment tool is associated with better survival, particularly in older candidates. Centers always assessing frailty at admission are likely to have better graft survival rates. Transplant centers may utilize validated frailty assessment tools to secure KT access for appropriate candidates and to better allocate health care resources for patients identified as frail, particularly for older patients.


Subject(s)
Frailty , Kidney Failure, Chronic , Kidney Transplantation , Aged , Frailty/complications , Frailty/diagnosis , Frailty/epidemiology , Humans , Kidney Transplantation/adverse effects , Prospective Studies , Risk Factors
11.
Pediatr Nephrol ; 36(1): 143-151, 2021 01.
Article in English | MEDLINE | ID: mdl-32980942

ABSTRACT

BACKGROUND: In March 2020, COVID-19 infections began to rise exponentially in the USA, placing substantial burden on the healthcare system. As a result, there was a rapid change in transplant practices and policies, with cessation of most procedures. Our goal was to understand changes to pediatric kidney transplantation (KT) at the national level during the COVID-19 epidemic. METHODS: Using SRTR data, we examined changes in pediatric waitlist registration, waitlist removal or inactivation, and deceased donor and living donor (DDKT/LDKT) events during the start of the disease transmission in the USA compared with the same time the previous year. RESULTS: We saw an initial decrease in DDKT and LDKT by 47% and 82% compared with expected events and then a continual increase, with numbers reaching expected prepandemic levels by May 2020. In the early phase of the pandemic, waitlist inactivation and removals due to death or deteriorating condition rose above expected values by 152% and 189%, respectively. There was a statistically significant decrease in new waitlist additions (IRR 0.49 0.65 0.85) and LDKT (IRR 0.17 0.38 0.84) in states with high vs. low COVID activity. Transplant recipients during the pandemic were more likely to have received a DDKT, but had similar calculated panel-reactive antibody (cPRA) values, waitlist time, and cause of kidney failure as before the pandemic. CONCLUSIONS: The COVID-19 pandemic initially reduced access to kidney transplantation among pediatric patients in the USA but has not had a sustained effect.


Subject(s)
Kidney Transplantation/statistics & numerical data , Living Donors/statistics & numerical data , Waiting Lists/mortality , Adolescent , Adult , COVID-19/epidemiology , Child , Child, Preschool , Female , Health Services Accessibility/statistics & numerical data , Humans , Infant , Infant, Newborn , Male , Middle Aged , Pandemics , Registries , SARS-CoV-2 , United States/epidemiology , Young Adult
12.
Molecules ; 26(16)2021 Aug 21.
Article in English | MEDLINE | ID: mdl-34443661

ABSTRACT

Protein methyltransferases are vital to the epigenetic modification of gene expression. Thus, obtaining a better understanding of and control over the regulation of these crucial proteins has significant implications for the study and treatment of numerous diseases. One ideal mechanism of protein regulation is the specific installation of a photolabile-protecting group through the use of photocaged non-canonical amino acids. Consequently, PRMT1 was caged at a key tyrosine residue with a nitrobenzyl-protected Schultz amino acid to modulate protein function. Subsequent irradiation with UV light removes the caging group and restores normal methyltransferase activity, facilitating the spatial and temporal control of PRMT1 activity. Ultimately, this caged PRMT1 affords the ability to better understand the protein's mechanism of action and potentially regulate the epigenetic impacts of this vital protein.


Subject(s)
Epigenesis, Genetic/radiation effects , Protein Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/genetics , Repressor Proteins/genetics , Amino Acid Sequence/genetics , Amino Acids , Epigenesis, Genetic/genetics , Gene Expression/radiation effects , Humans , Methylation/radiation effects , Protein Methyltransferases/radiation effects , Protein-Arginine N-Methyltransferases/radiation effects , Repressor Proteins/radiation effects , Transcription Factors/genetics , Tyrosine/chemistry , Ultraviolet Rays
13.
Chembiochem ; 21(3): 310-314, 2020 02 03.
Article in English | MEDLINE | ID: mdl-31298807

ABSTRACT

Protein bioconjugates have many critical applications, especially in the development of therapeutics. Consequently, the design of novel methodologies to prepare protein bioconjugates is of great importance. Herein we present the development and optimization of a novel strategy to prepare bioconjugates through a genetically encoded [2+2+2] cycloaddition reaction. To do this, a novel unnatural amino acid (UAA) containing a dipropargyl amine functionality was synthesized and incorporated site specifically. This UAA-containing protein was reacted with an alkyne-containing fluorophore to afford a covalently linked, well-defined protein bioconjugate. This reaction is convenient with an optimized reaction time of just two hours at room temperature and yields a stable, polysubstituted benzene ring. Overall, this work contributes a new bioconjugation strategy to the growing toolbox of reactions to develop protein bioconjugates, which have a myriad of applications.


Subject(s)
Alkynes/chemistry , Amines/chemistry , Amino Acids/chemistry , Proteins/chemistry , Proteins/genetics , Cycloaddition Reaction , Models, Molecular , Molecular Structure
14.
J Hand Surg Am ; 44(1): 61.e1-61.e9, 2019 Jan.
Article in English | MEDLINE | ID: mdl-29908927

ABSTRACT

PURPOSE: Wear of polyethylene bearings represents a limiting factor in the long-term success of total elbow prostheses. Bearing stress is 1 factor contributing to accelerated wear. Physiological loading of total elbow prostheses and implant design influence upon bearing stresses have not been well described. This study evaluates bearing stresses in 3 commercially available implant designs under loads associated with daily living. METHODS: Motion tracking from a healthy volunteer helped establish a musculoskeletal model to simulate flexor and extensor muscle activation at 0°, 45°, and 90° of shoulder abduction with a 2.3-kg weight in hand-forces and moments were measured at the elbow. Resulting physiological joint reaction forces and moments were applied to finite element models of 3 total elbow bearing designs (Coonrad/Morrey, Nexel, and Discovery) to evaluate contact area and polyethylene stresses. RESULTS: Increasing shoulder abduction resulted in minimal changes to the elbow joint reaction force but greater joint moments. All implants showed greater peak stresses with increasing shoulder abduction-elbow varus. Discovery and Nexel achieved greater contact area (23% vs > 100%) and demonstrated up to 39% lower peak polyethylene stresses compared with the Coonrad/Morrey design. CONCLUSIONS: Shoulder abduction results in a varus moment at the elbow. Newer bearing designs (Nexel and Discovery) provide a combination of higher contact area, improved load sharing, reduced edge loading, and lower stresses through elbow range of motion when compared with a cylindrical hinge-bearing design (Coonrad/Morrey). CLINICAL RELEVANCE: Although the Coonrad/Morrey is a clinically successful prosthesis, our physiological loading model shows that Discovery and Nexel provide greater contact area, better load sharing and lower peak stresses. This may lead to a decrease in polyethylene wear rates and the eventual risks of osteolysis and aseptic loosening. Further studies are needed to determine how these findings translate clinically.


Subject(s)
Elbow Joint/physiology , Elbow Prosthesis , Prosthesis Design , Stress, Mechanical , Weight-Bearing/physiology , Arthroplasty, Replacement, Elbow/instrumentation , Computer Simulation , Finite Element Analysis , Healthy Volunteers , Humans , Male , Polyethylene , Range of Motion, Articular/physiology , Shoulder Joint/physiology
15.
Am J Transplant ; 18(3): 650-658, 2018 03.
Article in English | MEDLINE | ID: mdl-28834181

ABSTRACT

Thirty percent of kidney transplant recipients are readmitted in the first month posttransplantation. Those with donor-specific antibody requiring desensitization and incompatible live donor kidney transplantation (ILDKT) constitute a unique subpopulation that might be at higher readmission risk. Drawing on a 22-center cohort, 379 ILDKTs with Medicare primary insurance were matched to compatible transplant-matched controls and to waitlist-only matched controls on panel reactive antibody, age, blood group, renal replacement time, prior kidney transplantation, race, gender, diabetes, and transplant date/waitlisting date. Readmission risk was determined using multilevel, mixed-effects Poisson regression. In the first month, ILDKTs had a 1.28-fold higher readmission risk than compatible controls (95% confidence interval [CI] 1.13-1.46; P < .001). Risk peaked at 6-12 months (relative risk [RR] 1.67, 95% CI 1.49-1.87; P < .001), attenuating by 24-36 months (RR 1.24, 95% CI 1.10-1.40; P < .001). ILDKTs had a 5.86-fold higher readmission risk (95% CI 4.96-6.92; P < .001) in the first month compared to waitlist-only controls. At 12-24 (RR 0.85, 95% CI 0.77-0.95; P = .002) and 24-36 months (RR 0.74, 95% CI 0.66-0.84; P < .001), ILDKTs had a lower risk than waitlist-only controls. These findings of ILDKTs having a higher readmission risk than compatible controls, but a lower readmission risk after the first year than waitlist-only controls should be considered in regulatory/payment schemas and planning clinical care.


Subject(s)
Blood Group Incompatibility/immunology , HLA Antigens/immunology , Kidney Failure, Chronic/surgery , Kidney Transplantation/methods , Living Donors/supply & distribution , Patient Readmission/statistics & numerical data , Postoperative Complications , Adult , Case-Control Studies , Female , Follow-Up Studies , Glomerular Filtration Rate , Graft Survival , Hospitalization/statistics & numerical data , Humans , Isoantibodies/blood , Isoantibodies/immunology , Kidney Function Tests , Male , Middle Aged , Prognosis , Risk Factors
16.
Am J Nephrol ; 48(4): 235-241, 2018.
Article in English | MEDLINE | ID: mdl-30227406

ABSTRACT

BACKGROUND: Up to 31% of kidney transplant (KT) recipients experience early hospital readmission (EHR). We hypothesized that EHR among older KT recipients is higher than younger recipients due to increased comorbidities and higher prevalence of frailty. METHODS: We identified 22,458 older (age ≥65) and 86,372 younger (18 to < 65) first-time KT recipients (December 1, 1999 - December 31, 2014) using United States Renal Data System data. We estimated the association between patient-level characteristics and EHR (30 days post-KT discharge) with modified Poisson regression among older and younger KT recipients, separately. We estimated the association between graft loss and mortality and EHR using Cox proportional hazards. RESULTS: EHR was more common in older KT recipients (30.1 vs. 27.6%; p < 0.001). Risk factors for EHR that differed by recipient age included female sex, African American race, diabetes, smoking, dialysis vintage, donor age, and length of stay. Risk of graft loss associated with EHR was greater among older KT recipients (adjusted hazard ratio [aHR] 1.64, 95% CI 1.51-1.77, p < 0.001) than younger KT recipients (aHR 1.43, 95% CI 1.38-1.48, p < 0.001; interaction p < 0.01). However, the risk of mortality associated with EHR was greater among younger recipients (aHR 1.52, 95% CI 1.47-1.57, p < 0.001) than that in older -recipients (aHR 1.40, 95% CI 1.34-1.47, p < 0.001; interaction p < 0.01). CONCLUSIONS: Older KT recipients are more likely to experience EHR and are at a higher risk of graft loss after EHR than younger recipients. Targeted interventions to prevent EHR and subsequent graft loss in this population should be identified.


Subject(s)
Frailty/epidemiology , Graft Rejection/epidemiology , Kidney Failure, Chronic/mortality , Kidney Transplantation/adverse effects , Patient Readmission/statistics & numerical data , Adult , Age Factors , Aged , Female , Follow-Up Studies , Graft Rejection/therapy , Humans , Kidney Failure, Chronic/therapy , Length of Stay/statistics & numerical data , Longitudinal Studies , Male , Middle Aged , Prevalence , Renal Dialysis/statistics & numerical data , Risk Factors , Time Factors , Tissue Donors/statistics & numerical data , Transplant Recipients/statistics & numerical data , United States , Young Adult
17.
Clin Transplant ; 32(7): e13291, 2018 07.
Article in English | MEDLINE | ID: mdl-29791039

ABSTRACT

Racial disparities in living donor kidney transplantation (LDKT) persist but the most effective target to eliminate these disparities remains unknown. One potential target could be delays during completion of the live donor evaluation process. We studied racial differences in progression through the evaluation process for 247 African American (AA) and 664 non-AA living donor candidates at our center between January 2011 and March 2015. AA candidates were more likely to be obese (38% vs 22%: P < .001), biologically related (66% vs 44%: P < .001), and live ≤50 miles from the center (64% vs 37%: P < .001) than non-AAs. Even after adjusting for these differences, AAs were less likely to progress from referral to donation (aHR for AA vs non-AA: 0.26 0.47 0.83; P = .01). We then assessed racial differences in completion of each step of the evaluation process and found disparities in progression from medical screening to in-person evaluation (aHR: 0.41 0.620.94; P = .02) and from clearance to donation (aHR: 0.28 0.510.91; P = .02), compared with from referral to medical screening (aHR: 0.78 1.021.33; P = .95) and from in-person evaluation to clearance (aHR: 0.59 0.931.44; P = .54). Delays may be a manifestation of the transplant candidate's social network, thus, targeted efforts to optimize networks for identification of donor candidates may help address LDKT disparities.


Subject(s)
Black or African American/statistics & numerical data , Healthcare Disparities/trends , Kidney Failure, Chronic/ethnology , Kidney Transplantation/statistics & numerical data , Living Donors/statistics & numerical data , White People/statistics & numerical data , Adult , Donor Selection , Female , Follow-Up Studies , Humans , Kidney Failure, Chronic/surgery , Male , Middle Aged , Needs Assessment , Treatment Outcome , United States
18.
Ann Plast Surg ; 81(1): 50-54, 2018 07.
Article in English | MEDLINE | ID: mdl-29762439

ABSTRACT

PURPOSE: The purpose of this study is to report clinical outcomes in a cohort of 12 patients with explosion injuries to the hand. METHODS: Twelve male patients with a mean age of 42.4 years (SD, 7.2) were examined at a mean of 54 months after sustaining explosion injuries to the hand. All patients underwent primary reconstruction and early soft tissue coverage within 72 hours after their injuries. Total active range of motion and moving 2-point discrimination in each digit were recorded along with hand injury severity score (HISS), disability of the arm, shoulder, and hand (DASH) score, and American Medical Association (AMA) impairment ratings. RESULTS: For digits saved, the average total active motion at final follow-up was 215 degrees (SD, 66.5). Twenty-two digits had 6-mm 2-point discrimination, and 17 digits had 8- to 10-mm 2-point discrimination. Eight of the 12 patients had secondary procedures. We found a strong correlation between initial HISS and DASH scores at final follow-up. There was also a strong correlation between AMA impairment rating and DASH scores. CONCLUSIONS: Early reconstruction provides protective sensation and preserves some function after explosion injuries. Preoperative HISS correlates with the long-term functional outcome as measured by DASH scores. For this group of patients, postinjury AMA impairment ratings also correlate with functional outcomes for the upper extremity.


Subject(s)
Blast Injuries/surgery , Disability Evaluation , Explosions , Hand Injuries/surgery , Injury Severity Score , Adult , Blast Injuries/physiopathology , Cohort Studies , Hand/surgery , Hand Injuries/physiopathology , Humans , Male , Middle Aged , Plastic Surgery Procedures/methods , Recovery of Function
20.
Ann Surg ; 266(6): 1084-1090, 2017 12.
Article in English | MEDLINE | ID: mdl-27655240

ABSTRACT

OBJECTIVE: To test whether frailty, a novel measure of physiologic reserve, is associated with longer kidney transplant (KT) length of stay (LOS), and modifies the association between LOS and mortality. BACKGROUND: Better understanding of LOS is necessary for informed consent and discharge planning. Mortality resulting from longer LOS has important regulatory implications for hospital and transplant programs. Which recipients are at risk of prolonged LOS and its effect on mortality are unclear. Frailty is a novel preoperative predictor of poor KT outcomes including delayed graft function, early hospital readmission, immunosuppression intolerance, and mortality. METHODS: We used registry-augmented hybrid methods, a novel approach to risk adjustment, to adjust for LOS risk factors from the Scientific Registry of Transplant Recipients (n = 74,859) and tested whether (1) frailty, measured immediately before KT in a novel cohort (n = 589), was associated with LOS (LOS: negative binomial regression; LOS ≥2 weeks: logistic regression) and (2) whether frailty modified the association between LOS and mortality (interaction term analysis). RESULTS: Frailty was independently associated with longer LOS [relative risk = 1.15, 95% confidence interval (CI): 1.03-1.29; P = 0.01] and LOS ≥2 weeks (odds ratio = 1.57, 95% CI: 1.06-2.33; P = 0.03) after accounting for registry-based risk factors, including delayed graft function. Frailty also attenuated the association between LOS and mortality (nonfrail hazard rate = 1.55 95% CI: 1.30-1.86; P < 0.001; frail hazard rate = 0.97, 95% CI: 0.79-1.19, P = 0.80; P for interaction = 0.001). CONCLUSIONS: Frail KT recipients are more likely to experience a longer LOS. Longer LOS among nonfrail recipients may be a marker of increased mortality risk. Frailty is a measure of physiologic reserve that may be an important clinical marker of longer surgical LOS.


Subject(s)
Frailty , Kidney Transplantation/mortality , Length of Stay , Aged , Female , Humans , Male , Middle Aged , Prospective Studies , Registries , Risk Factors
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