Accuracy and Feasibility of Clinically Applied Frailty Instruments before Surgery: A Systematic Review and Meta-analysis.

BACKGROUND: A barrier to routine preoperative frailty assessment is the large number of frailty instruments described. Previous systematic reviews estimate the association of frailty with outcomes, but none have evaluated outcomes at the individual instrument level or specific to clinical assessment of frailty, which must combine accuracy with feasibility to support clinical practice. METHODS: The authors conducted a preregistered systematic review (CRD42019107551) of studies prospectively applying a frailty instrument in a clinical setting before surgery. Medline, Excerpta Medica Database, Cochrane Library and the Comprehensive Index to Nursing and Allied Health Literature, and Cochrane databases were searched using a peer-reviewed strategy. All stages of the review were completed in duplicate. The primary outcome was mortality and secondary outcomes reflected routinely collected and patient-centered measures; feasibility measures were also collected. Effect estimates were pooled using random-effects models or narratively synthesized. Risk of bias was assessed. RESULTS: Seventy studies were included; 45 contributed to meta-analyses. Frailty was defined using 35 different instruments; five were meta-analyzed, with the Fried Phenotype having the largest number of studies. Most strongly associated with: mortality and nonfavorable discharge was the Clinical Frailty Scale (odds ratio, 4.89; 95% CI, 1.83 to 13.05 and odds ratio, 6.31; 95% CI, 4.00 to 9.94, respectively); complications was associated with the Edmonton Frail Scale (odds ratio, 2.93; 95% CI, 1.52 to 5.65); and delirium was associated with the Frailty Phenotype (odds ratio, 3.79; 95% CI, 1.75 to 8.22). The Clinical Frailty Scale had the highest reported measures of feasibility. CONCLUSIONS: Clinicians should consider accuracy and feasibility when choosing a frailty instrument. Strong evidence in both domains support the Clinical Frailty Scale, while the Fried Phenotype may require a trade-off of accuracy with lower feasibility.

A new model of arteriovenous fistula to study hemodialysis access complications.

PURPOSE: This report presents a new animal model of arteriovenous fistula (AVF) with attention given to surgical techniques as well as hemodynamic and pathologic measurements. Of note, this model was created with a tunneled central catheter with the purpose of studying therapeutic interventions, including hemodialysis. METHODS: Side-common carotid artery to end-external jugular vein AVFs were created in eight minipigs. A tunneled central catheter was also placed in the internal jugular vein. After 28 days, hemodynamic measurements of AVF flow and stenosis were performed. The minipigs were then euthanized and the AVFs were harvested for pathologic measurements of neointimal hyperplasia and thrombus volumes. In order to account for variable size of the AVFs, percentage luminal stenosis and degree of intima-media thickening were calculated. RESULTS: After 28 days, all eight AVFs remained patent. On average, 19% of arterial blood flow that approached the AVF traveled through the anastomosis. The average luminal stenosis by angiogram was 61.1%. The average neointimal hyperplasia and thrombus volumes were 1.4×10(8) and 3.8×10(8) µm3, respectively. The average luminal stenosis and intima-media thickening were 65.2% and 430.4 µm, respectively. CONCLUSIONS: This AVF model is ideal because of the relative ease of surgery and husbandry, lack of complications, as well as consistent and rapid development of the neointimal lesion which underlies AVF failure.