Rules of 6 criteria predict dialysis fistula maturation but not all rules are equal.

OBJECTIVE: The Rules of 6 (flow volume >600 mL/min, vein diameter >6 mm, vein depth <6 mm) are widely used to determine when an arteriovenous fistula (AVF) will support dialysis. Thus, we tested the utility of the Rules of 6 in clinical practice. METHODS: We retrospectively reviewed AVFs created at a single center from 2016 to 2019 for patients who had undergone dialysis within the same healthcare system. Clinical records and postoperative ultrasound studies were reviewed for the Rules of 6 criteria. Maturation was defined as use of the AVF with two needles for 75% of the dialysis sessions for a continuous 4-week period, with a mean flow of 300 mL/min or urea clearance (Kt/V) of 1.2. Predictors of maturation were assessed using logistic regression and receiver operating characteristic (ROC) curves. RESULTS: Five surgeons performed 202 AVFs of three types during 2016 to 2019 (radial-cephalic, n = 49; brachial-cephalic, n = 87; brachial-basilic, n = 66). Maturation occurred in 150 AVFs (74%; primary, n = 101 [50%]; assisted, n = 49 [24%]), while 52 (26%) failed to mature. Maturation did not vary by AVF type or patient sex or diabetes status. A higher body mass index was associated with failure to mature (P = .004). Only 16 mature AVFs (11%) met all three Rules of 6 using mean values for flow, diameter, and depth. However, 101 (67%) met all three Rules using the extreme, maximum or minimum, values. On multivariate analysis, each Rule of 6 was independently associated with maturation. If all three Rules were met, the AVF was nearly 10-fold more likely to have matured compared with an AVF satisfying no Rule. The body mass index correlated strongly with the vein depth (P < .001); however, both characteristics independently predicted maturation. The chance of maturation was highest if flow and depth Rules were met (positive predictive value [PPV], 93%); if all three rules were met, the PPV was 92%. The ROC area under curve (AUC) values for meeting flow volume and vein depth Rules together were higher than if all three Rules had been satisfied (0.784 vs 0.754). The PPV for diameter alone (78%) was the lowest of all PPVs for the three Rules and the ROC-AUC was only 0.588. If all three Rules together were not satisfied using extreme values, the negative predictive value was only 47%. CONCLUSIONS: The Rules of 6 predict AVF maturation, especially when using extreme, maximum or minimum, values to satisfy each Rule. Flow volume and vein depth together predict maturation equally as well as meeting all three Rules. Vein diameter seems less important. The Rules of 6 might be too stringent if used exclusively to predict for functional AVF maturation.

Contemporary outcomes of traumatic popliteal artery injury repair from the popliteal scoring assessment for vascular extremity injury in trauma study.

OBJECTIVE: Traumatic popliteal artery injuries are associated with the greatest risk of limb loss of all peripheral vascular injuries, with amputation rates of 10% to 15%. The purpose of the present study was to examine the outcomes of patients who had undergone operative repair for traumatic popliteal arterial injuries and identify the factors independently associated with limb loss. METHODS: A multi-institutional retrospective review of all patients with traumatic popliteal artery injuries from 2007 to 2018 was performed. All the patients who had undergone operative repair of popliteal arterial injuries were included in the present analysis. The patients who had required a major lower extremity amputation (transtibial or transfemoral) were compared with those with successful limb salvage at the last follow-up. The significant predictors (P < .05) for amputation on univariate analysis were included in a multivariable analysis. RESULTS: A total of 302 patients from 11 institutions were included in the present analysis. The median age was 32 years (interquartile range, 21-40 years), and 79% were men. The median follow-up was 72 days (interquartile range, 20-366 days). The overall major amputation rate was 13%. Primary repair had been performed in 17% of patients, patch repair in 2%, and interposition or bypass in 81%. One patient had undergone endovascular repair with stenting. The overall 1-year primary patency was 89%. Of the patients who had lost primary patency, 46% ultimately required major amputation. Early loss (within 30 days postoperatively) of primary patency was five times more frequent for the patients who had subsequently required amputation. On multivariate regression, the significant perioperative factors independently associated with major amputation included the initial POPSAVEIT (popliteal scoring assessment for vascular extremity injury in trauma) score, loss of primary patency, absence of detectable immediate postoperative pedal Doppler signals, and lack of postoperative antiplatelet therapy. Concomitant popliteal vein injury, popliteal injury location (P1, P2, P3), injury severity score, and tibial vs popliteal distal bypass target were not independently associated with amputation. CONCLUSIONS: Traumatic popliteal artery injuries are associated with a significant rate of major amputation. The preoperative POPSAVEIT score remained independently associated with amputation after including the perioperative factors. The lack of postoperative pedal Doppler signals and loss of primary patency were highly associated with major amputation. The use of postoperative antiplatelet therapy was inversely associated with amputation, perhaps indicating a protective effect.

Popliteal scoring assessment for vascular extremity injuries in trauma study.

OBJECTIVE: Traumatic popliteal vascular injuries are associated with the highest risk of limb loss of all peripheral vascular injuries. A method to evaluate the predictors of amputation is needed because previous scores could not be validated. In the present study, we aimed to provide a simplified scoring system (POPSAVEIT [popliteal scoring assessment for vascular extremity injuries in trauma]) that could be used preoperatively to risk stratify patients with traumatic popliteal vascular injuries for amputation. METHODS: A review of patients sustaining traumatic popliteal artery injuries was performed. Patients requiring amputation were compared with those with limb salvage at the last follow-up. Of these patients, 80% were randomly assigned to a training group for score generation and 20% to a testing group for validation. Significant predictors of amputation (P < .1) on univariate analysis were included in a multivariable analysis. Those with P < .05 on multivariable analysis were assigned points according to the relative value of their odds ratios (ORs). Receiver operating characteristic curves were generated to determine low- vs high-risk scores. An area under the curve of >0.65 was considered adequate for validation. RESULTS: A total of 355 patients were included, with an overall amputation rate of 16%. On multivariate regression analysis, the risk factors independently associated with amputation in the final model were as follows: systolic blood pressure <90 mm Hg (OR, 3.2; P = .027; 1 point), associated orthopedic injury (OR, 4.9; P = .014; 2 points), and a lack of preoperative pedal Doppler signals (OR, 5.5; P = .002; 2 points [or 1 point for a lack of palpable pedal pulses if Doppler signal data were unavailable]). A score of ≥3 was found to maximize the sensitivity (85%) and specificity (49%) for a high risk of amputation. The receiver operating characteristic curve for the validation group had an area under the curve of 0.750, meeting the threshold for score validation. CONCLUSIONS: The POPSAVEIT score provides a simple and practical method to effectively stratify patients preoperatively into low- and high-risk major amputation categories.

Patient-Surgeon Agreement in Assessment of Frailty, Physical Function, & Social Activity.

BACKGROUND: The shared decision-making process between surgical providers and patients relies on a joint understanding about the risks of different treatment options based on a patient's individual health state. However, it is unclear whether a patient's perception of their own condition is congruent with the health state assigned by their surgical providers. This study was designed to compare provider assessment of frailty versus patient-reported outcome (PRO) measures of their own frailty status, physical function, and social activity level. METHODS: We prospectively assessed patients presenting to a vascular surgery clinic at an academic institution between May 2018 and June of 2019. Before clinic examination, patients completed PROs of their frailty status (Frail Non-Disabled survey), physical function (patient-reported outcome measurement information system [PROMIS] v1.2), and social activity level (PROMIS v2.0). Next, each patient's frailty status and overall health were scored by a surgical provider using the 9-point Clinical Frailty Scale, a validated frailty assessment tool that incorporates their functional status and level of activity. The correlation between the provider and PROs for frailty, physical function, and social activity was determined using the Spearman rank test, sensitivity/specificity tests, and receiver operating curves. Logistic regression models were used to predict 1-y mortality after assessment. RESULTS: A total of 118 patients were evaluated in clinic (50% male with mean age of 60 y), including 35 (30%) who were categorized as being frail by the surgical provider. In comparison, the same patients were much more likely to self-report as having low physical function (73%), being frail or disabled (79%), and/or unable to engage in social activities (78%). Although there was high sensitivity (89%) between a provider's and PROs for frailty, the specificity was low (26%) resulting in a receiver operating curve area of 0.57. Overall, there was low correlation between PROs for frailty (r = 0.16), physical function (r = 0.21), and social activities (r = 0.21) when compared with a provider's assessment of patient frailty. Models using PROs for frailty had better discrimination for predicting 1-y mortality (c-statistic: 0.72) than those using the Clinical Frailty Scale (c-statistic: 0.62). CONCLUSIONS: Patients are more likely to self-report being frail, having low physical function, and limited social activity than what is detected by their surgical providers. These findings suggest that low levels of patient activity and its associated risk may often be underappreciated by surgical providers. Efforts are needed to improve how PROs are incorporated into surgical decision-making and outcome assessment.

Preoperative frailty assessment predicts loss of independence after vascular surgery.

OBJECTIVE: Frailty, a clinical syndrome associated with loss of metabolic reserves, is prevalent among patients who present to vascular surgery clinics for evaluation. The Clinical Frailty Scale (CFS) is a rapid assessment method shown to be highly specific for identifying frail patients. In this study, we sought to evaluate whether the preoperative CFS score could be used to predict loss of independence after major vascular procedures. METHODS: We identified all patients living independently at home who were prospectively assessed using the CFS before undergoing an elective major vascular surgery procedure (admitted for >24 hours) at an academic medical center between December 2015 and December 2017. Patient- and procedure-level clinical data were obtained from our institutional Vascular Quality Initiative registry database. The composite outcome of discharge to a nonhome location or 30-day mortality was evaluated using bivariate and multivariate regression models. RESULTS: A total of 134 independent patients were assessed using the CFS before they underwent elective open abdominal aortic aneurysm repair (8%), endovascular aneurysm repair (26%), thoracic endovascular aortic repair (6%), suprainguinal bypass (6%), infrainguinal bypass (16%), carotid endarterectomy (19%), or peripheral vascular intervention (20%). Among 39 (29%) individuals categorized as being frail using the CFS, there was no significant difference in age or American Society of Anesthesiologists physical status compared with nonfrail patients. However, frail patients were significantly more likely to need mobility assistance after surgery (62% frail vs 22% nonfrail; P < .01) and to be discharged to a nonhome location (22% frail vs 6% nonfrail; P = .01) or to die within 30 days after surgery (8% frail vs 0% nonfrail; P < .01). Preoperative frailty was associated with a >12-fold higher risk (odds ratio, 12.1; 95% confidence interval, 2.17-66.96; P < .01) of 30-day mortality or loss of independence, independent of the vascular procedure undertaken. CONCLUSIONS: The CFS is a practical tool for assessing preoperative frailty among patients undergoing elective major vascular surgery and can be used to predict likelihood of requiring discharge to a nursing facility or death after surgery. The identification of frail patients before major surgery can help manage postoperative expectations and optimize transitions of care.

Frailty assessment in vascular surgery and its utility in preoperative decision making.

The average patient requiring vascular surgery has become older, as life expectancy within the US population has increased. Many older patients have some degree of frailty and reside near the limit of their physiological reserve with restricted ability to respond to stressors such as surgery. Frailty assessment is an important part of the preoperative decision-making process, in order to determine whether patients are fit enough to survive the vascular surgery procedure and live long enough to benefit from the intervention. In this review, we will discuss different measures of frailty assessment and how they can be used by vascular surgery providers to improve preoperative decision making and the quality of patient care.