Temporal Trends, Determinants, and Outcomes of Inpatient versus Outpatient Arteriovenous Fistula Operations.

BACKGROUND: As high healthcare costs are increasing scrutinized, a movement toward reducing patient hospital admissions and lengths of stay has emerged, particularly for operations that may be performed safely in the outpatient setting. Our aim is to describe recent temporal trends in the proportion of dialysis access procedures performed on an inpatient versus outpatient basis and to determine the effects of these changes on perioperative morbidity and mortality. METHODS: The 2005-2008 American College of Surgeons National Surgical Quality Improvement Program database was queried for all primary arteriovenous fistula (AVF) procedures using current procedural terminology codes. Changes in the proportions of inpatient versus outpatient operations performed by year, as well as the associated 30-day postoperative morbidity and mortality, were analyzed using univariable statistics and multivariable logistic regression. RESULTS: Two thousand nine hundred fifty AVF procedures were performed over the study period. Overall, 71.7% (n = 2,114) were performed on an outpatient basis. Inpatient procedures were associated with higher 30-day morbidity (10.5% vs. 4.5%) and mortality (2.8% vs. 0.7%) than outpatient procedures (both, P < 0.001). There was a significant increase in the proportion of procedures performed on an outpatient basis over time (2005: 56% vs. 2008: 75%; P < 0.001). There were no changes in postoperative morbidity or mortality for inpatient or outpatient AVF over time (P ≥ 0.36). Independent determinants of having an inpatient procedure included younger age (OR 0.99), increasing ASA class (ASA IV OR 1.56), congestive heart failure (OR 3.32), recent ascites (OR 3.25), poor functional status (OR 3.22), the presence of an open wound (OR 1.91), and recent sepsis (OR 6.06) (all, P < 0.01). Acute renal failure (OR 2.60) and current dialysis (OR 1.44) were also predictive (P < 0.001). After correcting for baseline differences between groups, the adjusted OR for both morbidity (aOR 1.93, 95% CI 1.38-2.69) and mortality (aOR 2.85, 95% CI 1.36-5.95) remained significantly higher for inpatient versus outpatient AVF. CONCLUSIONS: Dialysis access operations are increasingly being performed on an outpatient basis, with stable perioperative outcomes. Inpatient procedures are associated with worse outcomes, likely because they are reserved for patients with acute illnesses, serious comorbidities, and poor functional status. Overall, for appropriately selected patients, the movement toward performing more elective dialysis access operations on an outpatient basis is associated with acceptable outcomes.

Operative variables are better predictors of postdischarge infections and unplanned readmissions in vascular surgery patients than patient characteristics.

OBJECTIVE: Although postoperative readmissions are frequent in vascular surgery patients, the reasons for these readmissions are not well characterized, and effective approaches to their reduction are unknown. Our aim was to analyze the reasons for vascular surgery readmissions and to report potential areas for focused efforts aimed at readmission reduction. METHODS: The 2012 to 2013 American College of Surgeons National Quality Improvement Program (ACS NSQIP) data set was queried for vascular surgery patients. Multivariable models were developed to analyze risk factors for postdischarge infections, the major drivers of unplanned 30-day readmissions. RESULTS: We identified 86,403 vascular surgery patients for analysis. Thirty-day readmission occurred in 8827 (10%), of which 8054 (91%) were unplanned. Of the unplanned readmissions, 61% (n = 4951) were related to the index vascular surgery procedure. Infectious complications were the most common reason for a surgery-related readmission (1940 [39%]), with surgical site infection being the most common type of infection related to unplanned readmission. Multivariable analysis showed the top five preoperative risk factors for postdischarge infections were the presence of a preoperative open wound, inpatient operation, obesity, work relative value unit, and insulin-dependent diabetes (but not diabetes managed with oral medications). Cigarette smoking was a weak predictor and came in tenth in the mode (overall C index, 0.657). When operative and postoperative factors were included in the model, total operative time was the strongest predictor of postdischarge infectious complications (odds ratio [OR] 1.2 for each 1-hour increase in operative time), followed by presence of a preoperative open wound (OR, 1.5), inpatient operation (OR, 2), obesity (OR, 1.8), and discharge to rehabilitation facility (OR, 1.7; P < .001 for all). Insulin-dependent diabetes, cigarette smoking, dialysis dependence, and female gender were also predictive, albeit with smaller effects (OR, 1.1-1.3 for all; P < .001). The overall fit of the multivariable model was fair (C statistic, 0.686). CONCLUSIONS: Infectious complications dominate the reasons for unplanned 30-day readmissions in vascular surgery patients. We have identified preoperative, operative, and postoperative risk factors for these infections with the goal of reducing these complications and thus readmissions. Expected patient risk factors, such as diabetes, obesity, renal insufficiency, and cigarette smoking, were less important in predicting infectious complications compared with operative time, presence of a preoperative open wound, and inpatient operation. Our findings suggest that careful operative planning and expeditious operations may be the most effective approaches to reducing infections and thus readmissions in vascular surgery patients.

A Fourteen-Year Experience with Vascular Anomalies Encountered during Transaxillary Rib Resection for Thoracic Outlet Syndrome.

BACKGROUND: Transaxillary approach to first rib resection and scalenectomy (TAFRRS) is a well-established technique for treatment of thoracic outlet syndrome (TOS). Although anatomic features encountered during TAFRRS are in general constant, vascular anomalies may be encountered but have not been described to date. Herein we describe vascular abnormalities encountered during TAFRRS. METHODS: We performed a retrospective review of a prospective practice database of 224 operations for TOS performed in 172 patients from March 2000 to March 2014. We excluded 10 patients with missing operative reports, 3 reoperations on the same patient, and 8 non-transaxillary resections. We recorded vascular anomalies identified in operative reports and reviewed computed tomography imaging to delineate the nature of these abnormalities. RESULTS: The overall incidence of vascular anomalies was 11% (22 of 203 TAFRRS). Most patients with anomalies had venous TOS (vTOS) (9 patients, 41%), followed by 7 (32%) with neurogenic TOS (nTOS). The remainder of the patients had arterial TOS (aTOS) (6 patients, 27%). Seven patients (32%) had an abnormal subclavian artery (SCA) with 5 (23%) having an abnormal arterial course in the anterior scalene muscle (ASM); 6 patients (27%) had an abnormal internal mammary artery (IMA) originating from distal SCA; 4 (18%) had abnormalities in the supreme thoracic artery (bifurcation or duplication); 2 (9%) had an abnormal branch from the SCA with anomalous location in the operative field; and 3 (14%) had an abnormal large venous branch penetrating the ASM. In the 19 patients with arterial anomalies, 8 (42%) were recognized as arterial branches penetrating the ASM, and 11 (58%) were noticed as they had anomalous arterial locations within the operative field. Most arterial anomalies were seen in vTOS (9, 45%), followed by nTOS (7, 35%). No intraoperative vascular complications occurred. Perioperative complications included 1 occurrence of postoperative transfusion for bleeding following axillary drain discontinuation and 2 Horner's syndromes. One aberrant IMA was electively ligated to allow complete thoracic outlet decompression. CONCLUSIONS: Arterial anomalies during TAFRRS are encountered in 11% of operations, and may present with vessel locations in unusual areas within the operative field, or as abnormal vessels penetrating the ASM, thus making scalenectomy precarious. Careful attention must be paid to possible abnormal locations of vessels in the thoracic outlet to avoid bleeding complications.

Drivers of readmissions in vascular surgery patients.

OBJECTIVE: Postoperative readmissions are frequent in vascular surgery patients, but it is not clear which factors are the main drivers of readmissions. Specifically, the relative contributions of patient comorbidities vs those of operative factors and postoperative complications are unknown. We sought to study the multiple potential drivers of readmission and to create a model for predicting the risk of readmission in vascular patients. METHODS: The 2012-2013 American College of Surgeons National Surgical Quality Improvement Program data set was queried for unplanned readmissions in 86,238 vascular patients. Multivariable forward selection logistic regression analysis was used to model the relative contributions of patient comorbidities, operative factors, and postoperative complications for readmission. RESULTS: The unplanned readmission rate was 9.3%. The preoperative model based on patient demographics and comorbidities predicted readmission risk with a low C index of .67; the top five predictors of readmission were American Society of Anesthesiologists class, preoperative open wound, inpatient operation, dialysis dependence, and diabetes mellitus. The postoperative model using operative factors and postoperative complications predicted readmission risk better (C index, .78); postoperative complications were the most significant predictor of readmission, overpowering patient comorbidities. Importantly, postoperative complications identified before discharge from the hospital were not a strong predictor of readmission as the model using predischarge postoperative complications had a similar C index to our preoperative model (.68). However, the inclusion of complications identified after discharge from the hospital appreciably improved the predictive power of the model (C index, .78). The top five predictors of readmission in the final model based on patient comorbidities and postoperative complications were postdischarge deep space infection, superficial surgical site infection, pneumonia, myocardial infection, and sepsis. CONCLUSIONS: Readmissions in vascular surgery patients are mainly driven by postoperative complications identified after discharge. Thus, efforts to reduce vascular readmissions focusing on inpatient hospital data may prove ineffective. Our study suggests that interventions to reduce vascular readmissions should focus on prompt identification of modifiable postdischarge complications.

Accurate preoperative prediction of unplanned 30-day postoperative readmission using 8 predictor variables.

BACKGROUND: Unplanned postoperative readmissions are associated with high costs, may indicate poor care quality, and present a substantial opportunity for healthcare quality improvement. Patients want to know their risk of unplanned readmission, and surgeons need to know the risk to adequately counsel their patients. The Surgical Risk Preoperative Assessment System tool was developed from the American College of Surgeons National Surgical Quality Improvement Program dataset and is a parsimonious model using 8 predictor variables. Surgical Risk Preoperative Assessment System is applicable to >3,000 operations in 9 surgical specialties, predicts 30-day postoperative mortality and morbidity, and is incorporated into our electronic health record. METHODS: A Surgical Risk Preoperative Assessment System model was developed using logistic regression. It was compared to the 28 nonlaboratory variables model from the American College of Surgeons National Surgical Quality Improvement Program 2012 to 2017 dataset using the c-index as a measure of discrimination, the Hosmer-Lemeshow observed-to-expected plots testing calibration, and the Brier score, a combined metric of discrimination and calibration. RESULTS: Of 4,861,370 patients, 188,150 (3.98%) experienced unplanned readmission related to the index operation. The Surgical Risk Preoperative Assessment System model's c-index, 0.728, was 99.3% of that of the full model's, 0.733; the Hosmer-Lemeshow plots indicated good calibration; and the Brier score was 0.0372 for Surgical Risk Preoperative Assessment System and 0.0371 for the full model. CONCLUSION: The 8 variable Surgical Risk Preoperative Assessment System model detects patients at risk for postoperative unplanned, related readmission as accurately as the full model developed from all 28 nonlaboratory preoperative variables in the American College of Surgeons National Surgical Quality Improvement Program dataset. Therefore, unplanned readmission can be integrated into the existing Surgical Risk Preoperative Assessment System tool providing moderately accurate prediction of postoperative readmission.