Implementation of Enhanced Recovery Pathway for Lower Extremity Arterial Bypass Decreases Length of Stay

Abstract

Objective:

Frailty, nutrition, and comorbid conditions are all challenges that contribute to significant morbidity in patients undergoing lower extremity arterial bypass (LEAB). Evidence supports that enhanced recovery pathways (ERP) can improve perioperative outcomes. However, few studies have demonstrated successful implementation of an ERP for LEAB. The goal of this study was to demonstrate successful implementation of an ERP in a complex patient population undergoing LEAB, including elective, urgent, or emergent procedures with the goal of reducing length of stay and morbidity for patients undergoing these procedures at our institution.

Methods:

Multi-stakeholder meetings with representatives from all vascular surgery practice sites in the Northwestern Medicine system were conducted to review current evidence-based practices and finalize an ERP for patients undergoing LEAB. Pathway elements included standardized patient education, minimal perioperative fasting with preoperative carbohydrate loading, opioid-sparing analgesia, and early postoperative diet and mobilization. The ERP was initiated in February 2022 as a pilot at a single institution. At 20 months, patient data and process and outcome measures were abstracted from the medical record and validated by four independent reviewers for univariate analysis.

Results:

Over the 20-month study period, 112 patients underwent LEAB. Process measures were tracked to determine compliance with the ERP. Patients had to receive >70% of the pathway elements to be considered part of the ERP (n=60). If patients missed more than 30% of the elements, they were analyzed as traditional pathway (TP) (n=52). There were no significant differences in patient demographics, BMI, or hemoglobin A1c. ERP patients were more likely to be elective (76.7% vs. 48.1%, p=0.0004) and for CLTI (76.7% vs. 48.1%, p=0.001) and less likely to be urgent or emergent. No significant difference was observed in frequency of infrageniculate bypass target or operative duration. Compliance with 10 perioperative process measures ranged from 28–98% in the ERP group. Compliance was most successful with preoperative education (81.6%), chlorhexidine wash (80.0%), postoperative mobilization (90.0%), early solid diet (98.3%), and postoperative opioid sparing strategies (98.3%). Challenges included preoperative acetaminophen (28.3%), carbohydrate load (33.8%), and postoperative protein supplementation (28.3%). Notably, ERP patients demonstrated significantly reduced total length of stay (7.8 vs. 13.6 days, p=0.014), postoperative length of stay (6.0 vs. 11.0 days, p=0.0058), and unplanned reoperations (10.0% vs. 28.9%, p=0.015) when compared to TP patients. ERP patients trended towards fewer unplanned readmissions (13.3% vs. 26.9%, p=0.095).

Discussion:

Our findings suggest that an ERP for LEAB is feasible in both elective and non-elective settings although compliance with the ERP individual elements was more challenging for patients undergoing procedures for emergent or urgent indications. Patients undergoing ERP had improved compliance with process measures, reduced length of stay and unplanned reoperation. Our results highlight the benefits of ERP for LEAB and the complex vascular surgery population and some of the potential barriers worth considering in this patient population.

Table of Contents Summary

The implementation of an enhanced recovery after surgery protocol for all patients undergoing lower extremity arterial bypass is associated with decreased length of stay in this single-center prospective cohort study. Enhanced recovery after surgery can be successfully implemented and improve outcomes, even in a complex patient population with high-acuity presentations.

INTRODUCTION

Enhanced Recovery After Surgery (ERAS) is an evidence-based multidisciplinary patient care approach composed of preoperative, intraoperative, and postoperative interventions with the goal of improving patient care and experience. Following emergence of perioperative protocols after colorectal and cardiac surgery, termed fast-track surgery in the 1990s, ERAS protocols were developed by the ERAS study group in 2001.¹ ERAS protocols have since been adopted across multiple surgical specialties and have shown reductions in mortality, complication rates, length of stay (LOS), surgery related anxiety, procedure related costs, opioid use, and increased postoperative functional capacity and life quality.^1–3 Given the morbidity associated with vascular procedures and the frailty of the population with atherosclerotic and aneurysmal disease, it follows that ERAS may provide significant benefit to patients following vascular surgery procedures. However, implementation and evidence of ERAS protocols in vascular surgery is scarce.⁴

Patients undergoing lower extremity arterial bypass (LEAB) for peripheral arterial disease (PAD) are an especially vulnerable population, with a combined 30-day mortality and major adverse cardiovascular event of 8.8%.⁵ This morbidity and mortality is a consequence of physiologic stress induced by surgical trauma in a patient population characterized by advanced age and medical complexity, including a high prevalence of diabetes, tobacco use, renal disease, as well as poor compliance with medical treatment.⁵ Given the complexity of the patient population and the associated risks of procedures, vascular patients are also at high risk for prolonged hospitalization and increased resource utilization.⁶ It follows that best practices in the care of patients undergoing lower extremity arterial bypass should aim to reduce the stress of the procedure in our frail population while minimizing the complexity and variation in the care pathway.

In 2023, the Society for Vascular Surgery (SVS), in collaboration with the ERAS Society, published the first consensus document for perioperative care for lower extremity vascular bypass structured around ERAS core elements. This landmark publication consisted of 26 perioperative recommendations for patients undergoing lower extremity arterial bypass for peripheral arterial disease (PAD).⁷ Despite recognition of the benefit of such ERAS protocols, few have reported real-world development and implementation of an enhanced recovery protocol (ERP) for lower extremity vascular bypass.⁸ Given the heterogenous development of ERPs and the paucity of reports, we sought to develop an ERP for LEAB across a healthcare system and hypothesized implementation of an ERP would improve patient postoperative outcomes.

METHODS

QUERI Model for Enhanced Recovery Pathway Development and Implementation

The Quality Enhancement Research Initiative (QUERI) model was employed to guide development and implementation of an ERP for LEAB (Figure 1). The RECOvER checklist was utilized to ensure compliance with recommended reporting guidelines for enhanced recovery protocols.⁹ The QUERI implementation roadmap provides a framework for pre-implementation, implementation, and sustainment of evidence-based practices.¹⁰ Details regarding application of each step in the QUERI model for our project are described below:

Figure 1 –

Quality Enhancement Research Initiative (QUERI) model utilized for ERP development and implementation.

Identify the Problem:

Patients undergoing LEAB were selected as our first system-wide vascular surgery ERP for several considerations. First, patients undergoing LEAB at our institution were outliers for length of stay and complications in the Vizient and infrainguinal bypass module of the Vascular Quality Initiative (VQI) databases, indicating an opportunity for improvement in outcomes. Second, we considered the complexity of ERAS implementation. Compared to procedures such as open aneurysm repair, we perform LEAB more frequently (~100 cases/year) and felt the regular volume would reinforce of the proposed changes. In addition, patients undergoing LEAB are cared for by our primary vascular surgery team. We felt this would reduce the variety and number of stakeholders that would need to be engaged during and after implementation. The final patient population included those undergoing any LEAB without the need for open suprainguinal revascularization. We included all case urgencies including elective, urgent, and emergent procedures. Similarly, we included all surgical indications including trauma, aneurysm, and infection. The International Classification of Diseases Version 10 (ICD-10) and Current Procedural Terminology (CPT) codes for LEAB were utilized to identify patients in the electronic medical record for analysis.

Define Best Practices:

ERP development began by establishing a Vascular Surgery Enhanced Recovery After Surgery (ERAS) Committee. The committee consisted of stakeholders from the vascular surgery service line and included surgeons, surgical trainees, advanced practice providers (APPs) from three hospitals in the Northwestern Medicine System (Northwestern Memorial Hospital (NMH), Central DuPage Hospital (CDH), and Lake Forest Hospital (LFH)) and quality and process improvement specialists from the Northwestern Memorial Hospital Quality Department. The committee created a process map detailing the existing perioperative process for patients undergoing LEAB and documented variation by institution. The committee then reviewed preexisting current enhanced recovery pathway protocols at Northwestern Medicine and evidence-based practices for the care of patients undergoing LEAB from the literature. A final list of proposed ERP elements was then incorporated into a future state process map. The draft protocol was then reviewed by multidisciplinary groups at Northwestern Memorial Hospital consisting of nurses, APPs, physicians, pharmacists, dieticians, and physical therapists organized by the process of care (preoperative, day of surgery, and postoperative). Feedback from multidisciplinary groups was then utilized by the vascular surgery ERAS committee to finalize the pathway (Supplemental Figure 1). The final step involved review and approval of the protocol by multidisciplinary stakeholders at each of the participating hospitals. Although the ERP elements were consistent at all sites, minor process variation within the elements between hospitals was acceptable (ex. NPO 2 vs. 3 hours prior to surgery).

Implement Interventions:

When feasible, the ERP elements were incorporated into electronic medical record changes (ex. ordersets and documentation templates). Educational materials such as checklists (Supplemental Figure 2) were also developed for the care team to facilitate ERP implementation. Once electronic medical record changes and stakeholder engagement and education were complete, the ERP went live at Northwestern Memorial Hospital on February 1, 2022, with planned expansion to other vascular surgery services across the system. Throughout the implementation phase, stakeholders were iteratively educated to ensure continued compliance with the ERP. The sustainment phase remains ongoing and currently all LEAB patients are included in the ERP. Details of ERP elements are as follows:

Preoperative Components:

Educational materials for both hospital staff and patients were iteratively developed prior to the initiation of the ERP. Hospital staff materials consisted of guidebooks and checklists distributed throughout vascular surgery workspaces. Electronic medical record components included modification of the case request order to include ERP designation, development of new smart phrases focusing primarily on pre-operative process measures, and new builds of preoperative order sets. New elements added to the preoperative process included nutrition and frailty screens, nutrition optimization, and surgical site infection prevention. Patient frailty was assessed via the National Surgical Quality Improvement Program (NSQIP) 5-Factor Modified Frailty Index (mFI-5) and documented in a standardized electronic medical record history & physical, further aided by a newly implemented smart phrase.¹¹ Patient nutritional status was assessed via a two question Malnutrition Screening Tool (MST) and documented in a similar fashion.¹² Patients were instructed to bathe with chlorhexidine for two days prior to surgery or ordered for chlorhexidine showers if inpatient.¹³ Patients were instructed to cease solid PO intake at midnight prior to surgery and allowed clear liquids until 2 hours prior to surgery, at which point they were instructed to drink a pre-surgery carbohydrate-loading drink (Ensure Pre-Surgery) (Supplemental Figure 3).¹⁴ Patients received 1g PO acetaminophen as opioid-sparing analgesia prior to surgery. Patient-facing materials consisted of an ERP education booklet, modification of existing preoperative pamphlets and instruction letters, and integration with a patient digital engagement platform (GetWell Loop).¹⁵ In addition to digital copies of the ERP education booklet, the GetWell Loop platform allowed real time reminders for patients for preoperative and postoperative elements.

Intraoperative Components:

Intraoperative ERP components span surgical, nursing, and anesthesia team workflows. Surgical site depilation was completed via a vacuum assisted shaver. Instrument trays for LEAB were standardized within each facility. Transverse groin incisions and skip incisions for vein harvest were utilized when able with avoidance of surgical drains.¹³ Sterile urinary catheters, when indicated, were placed by the nursing team. Intravenous fluid administration was anesthesia directed with euvolemia as a goal. Postoperative nausea and vomiting prophylaxis consisted of dexamethasone based on ideal body weight on induction and ondansetron at the start of closure. Opioid-sparing strategies included routine ketamine administration, lidocaine bolus at induction with continuous infusion unless contraindicated, and additional doses of intravenous acetaminophen.

Postoperative Components:

Postoperative ERP components focused on minimizing patient disruptions, rapid diet advancement, opioid-sparing analgesia, and early mobilization. Specifically, medications and assessments were clustered to daytime hours. Vitals were obtained every 4 hours for 48 hours and then prolonged to every 8 hours. Bedside ankle-brachial index, laboratory draws, and additional imaging were discontinued on postoperative day 3 unless contraindicated. Patient diet was advanced as tolerated with a goal of at least clear liquids on postoperative day 0 and resumption of solid intake on postoperative day 1 if not the day of surgery. Intravenous fluids were discontinued when the patient was tolerating a liquid diet. Highprotein supplements were provided until patient discharge. PO acetaminophen was scheduled with minimization of opioids. Patients were instructed to, at a minimum, sit at the edge of the bed on postoperative day 0 and out of bed with physical therapy and occupational therapy on postoperative day 1. All postoperative ERP components were aided by newly built order sets.

Document Improved Outcomes:

Monthly meetings with the Vascular Surgery ERAS Committee reviewed progress, feedback and determined the need for changes in the implementation plan. Small changes in the EMR were made to facilitate compliance with process measures. No core ERP elements were changed after implementation.

Data Abstraction & Statistical Analysis:

This study was deemed IRB exempt by the Northwestern University Institutional Review Board. While the ERP was developed across three hospitals in the Northwestern Medicine System, subsequent data abstraction and analysis is solely derived from patients undergoing LEAB at NMH. At 20 months, patient data and process and outcome measures were abstracted from the medical record and validated by four independent reviewers (CC, LL, DE, AV). A complete list of elements with accompanying definitions is provided in Supplemental Table 1. Data were analyzed with Prism 10.0 (GraphPad Software, San Diego, CA). An unpaired two-tailed t test was used for analysis of continuous variables with two groups. Fischer’s exact test was used for comparison of categorical variables. A P value of <0.05 was considered statistically significant.

RESULTS

Patient Demographics and Presentation

Implementation of the ERP started in February 2022 at Northwestern Memorial Hospital, a quaternary care 943-bed academic hospital in Chicago, IL. In the 20-month period after implementation, 112 patients underwent LEAB and 60 (53.6%) received >70% of the ERP elements (ERP cohort). Patients who received <70% of the ERP elements were analyzed as part of the traditional pathway (TP cohort). There were no significant differences in the age, sex, BMI, or racial composition of our two cohorts (Table 1). Most patients (75% ERP and 71.15% TP) were men, and the average age was 68.36 ± 12.62 and 67.37 ± 10.04 years, respectively. On average, patients were also overweight with a mean BMI of 27.83 ± 5.93 kg/m² in our ERP cohort and 28.72 ± 6.18 kg/m² in our TP cohort. With regards to comorbidities, there was a statistically significant difference (p = 0.015) between the smoking status characteristics in our two groups with a larger percentage of both current (ERP: 28.33%, n = 17 vs. TP: 23.84%, n = 15) and former (ERP: 61.67%, n = 37 vs. TP: 40.38%, n = 21) smokers in the ERP cohort (Table 1). Both groups also had similar baseline glycemic control as measured by preoperative hemoglobin A1c (ERP: 6.68 ± 1.07 mg/dL vs. TP: 6.57 ± 1.60 mg/dL, p=0.71) and glucose levels (ERP: 138.0 ± 66.99 mg/dL vs. TP: 133.3 ± 51.85 mg/dL, p=0.69).

Table 1 –

Patient demographics, presentation and procedure data

	ERP (n = 60)	TP (n = 52)	P-value
Age (years)	67.37 ± 10.04	68.36 ± 12.62	0.64
Sex			0.67
Male	75% (45)	71.15% (37)
Female	25% (15)	28.85% (15)
Race			0.30
Black	30% (18)	23.07% (12)
Hispanic	1.67% (1)	9.62% (5)
White	56.67% (34)	55.77% (29)
Asian	1. 67% (1)	1.92% (1)
Other	1.67% (1)	5.77% (3)
Declined	8.33% (5)	3.85% (2)
BMI (kg/m2)	27.83 ± 5.93	28.72 ± 6.18	0.44
Smoking Status			0.015
Current	28.33% (17)	23.84% (15)
Former	61.67% (37)	40.38% (21)
Never	10% (6)	30.77% (16)
Preoperative Hemoglobin A1c (mg/dL)	6.68 ± 1.07	6.57 ± 1.60	0.71
Preoperative Glucose (mg/dL)	138.0 ± 66.99	133.3 ± 51.85	0.69
Bypass Indication			0.0010
Claudication	6.67% (4)	0% (0)
Rest Pain	23.33% (14)	15.38% (8)
Tissue Loss	53.33% (32)	32.69% (17)
Acute Limb Ischemia	5% (3)	28.85% (15)
Aneurysm	6.67% (4)	9.62% (5)
Trauma	0% (0)	0% (0)
Other*	5% (3)	13.46% (7)
Case Urgency			0.0004
Elective	76.67% (46)	48.07% (25)
Urgent	15% (9)	13.46% (7)
Emergent	8.33% (5)	38.46% (20)
Procedure
Infrageniculate Target	76.67% (46)	80.76% (42)	0.65
Operative Length (min)	350.8 ± 103.0	385.3 ± 106.3	0.084
Estimated Blood Loss (mL)	555.4 ± 480.4	777.9 ± 551.1	0.024
Urine Output (mL/kg/hr)	1.534 ± 1.110	1.628 ± 1.159	0.667

^*Other indication = infection, threatened bypass. Categorical variables are presented as percentage (number). Continuous variables are presented as mean ± standard deviation.

Patients in the ERP cohort were more likely to undergo elective procedures. While the majority of patients undergoing bypass in both groups had tissue loss (53.33% ERP vs. 32.69% TP), bypass in ERP patients was rarely performed for acute limb ischemia when compared to the TP patients (5% ERP vs. 28.85% TP, p=0.0010). Differences in case urgency mirrored differences in case indication, which were also significantly different between the two groups. A significant difference in the distribution of case urgency was observed between ERP and TP groups (p = 0.0004) (Table 1). Most cases in the ERP group were elective, constituting 76.67% (n = 46) as compared to 48.07% (n = 25) in the TP group. While there were similar rates of urgent cases, there were very few emergent cases in the ERP group, with only 8.33% (n = 5) as opposed to 38.46% (n = 20) in the TP group.

Day of Surgery Data

Intraoperatively, the estimated blood loss (EBL) observed in the ERP cohort (555.4 ± 480.4 mL) was significantly less than that of the EBL in the TP cohort (777.9 ± 551.1 mL, p = 0.024) (Table 1). This potentially reflects the acuity of the presentation in the TP cohort. However, there was no significant difference observed in case complexity, as reflected by the percentage of cases with an infrageniculate target (76.67% ERP vs. 80.76% TP, p = 0.65) (Table 1), heparin administered (ERP: 10261 ± 3780 units vs. TP: 10418 ± 3784 units, p = 0.83), operative time (ERP: 350.8 ± 103 vs. TP: 385.3 ± 106.3 minutes, p = 0.084),), or postoperative temperature (ERP: 97.83 ± 0.44 °F vs. TP: 97.98 ± 0.76 °F, p = 0.17) (Table 2). Consistent with the opioid sparing strategy of routine ketamine administration, our ERP cohort had significantly increased ketamine utilization during the procedure, receiving on average 20.57 ± 29.47 mg compared to 8.25 ± 20.81 mg in the TP cohort (p = 0.013). Additionally, dexamethasone administration was also significantly higher in the ERP group with a mean dose of 3.93 ± 3.70 mg versus 2.58 ± 2.87 mg in the TP group (p = 0.034). Lidocaine usage did not differ significantly between groups. While not significant (p = 0.083), the ERP group received less fluid with a mean volume of 2,777 ± 1,308 mL compared to 3,264 ± 1,607 mL in the TP group. This may reflect a trend towards more restrictive fluid management in the ERP group, consistent with our enhanced recovery protocol. Despite decreased fluid resuscitation, both groups had similar UOP (ERP: 1.534 ± 1.110 vs. TP: 1.628 ± 1.159 mL/kg/hr, p = 0.67). Collectively, these findings support the efficacy of the ERP in promoting opioid sparing strategies and euvolemia.

Table 2 –

Compliance with enhanced recovery pathway process measures.

	ERP	TP	P-value
Preoperative
ERP Education/Nutrition Screen	81.67% (49)	17.31% (9)	<0.0001
Preoperative Chlorhexidine	80% (48)	40.38% (21)	<0.0001
Preoperative Acetaminophen	50% (30)	23.08% (12)	0.0037
Preoperative ERP Carb Drink	58.33% (35)	5.77% (3)	<0.0001
Day of Surgery and Postoperative
Intraoperative Acetaminophen	28.33% (17)	5.77% (3)	0.0024
Ketamine (mg)	20.57 ± 29.47	8.25 ± 20.81	0.013
Dexamethasone (mg)	3.93± 3.70	2.58 ± 2.87	0.034
Heparin (units)	10261 ± 3780	10418 ± 3784	0.83
Lidocaine (mg)	103.4 ± 146.0	108.1 ± 165.0	0.87
Intraoperative Fluids (mL)	2777 ± 1308	3264 ± 1607	0.083
Postoperative Temperature (F)	97.83 ± 0.44	97.98 ± 0.76	0.17
Postoperative Acetaminophen	98.33% (59)	94.23% (49)	0.34
Postoperative Protein Supplementation	28.33% (17)	36.54% (19)	0.42
POD0 Minimum CLD	80% (48)	57.69% (30)	0.014
POD1 Solid Diet	98.33% (59)	82.69% (43)	0.0055
POD1 Discontinuation of Fluids	95% (57)	76.92% (40)	0.010
POD1 PT/OT	90% (54)	76.92% (40)	0.074

CLD = clear liquid diet; PT = physical therapy; OT = occupational therapy

Categorical variables are presented as percentage (number).

Postoperative Outcomes

Patients included in the ERP had significantly reduced hospital length of stay, both total (7.77 ± 6.14 days ERP vs. 13.63 ± 16.96 TP, p = 0.014) and postoperatively (6.01 ± 4.56 days ERP vs. 11.02 ± 12.91 days TP, p = 0.0058) (Figure 2). Furthermore, the rate of return to the operating room was significantly lower in the ERP group at 10.00% (n = 6) compared to 28.85% (n = 15) in the TP group (p = 0.015). The rate of unplanned readmissions was also lower in the ERP group at 13.33% (n = 8), compared to 26.92% (n = 14) in the TP group; however, this difference did not reach statistical significance (p = 0.095). The 30-day mortality rate did not differ significantly between the groups, with one mortality in the ERP group and two mortalities in the TP group.

Figure 2 –

Enhanced recovery pathway improves postoperative outcomes. ERP: Enhanced Recovery Pathway. TP: Traditional Pathway. LOS: length of stay

Glycemic control in the immediate postoperative period whether on postoperative day 0, postoperative day 1, or postoperative day 3 did not show significant differences between the ERP and TP groups (Table 3). In our sub-group analysis of the ERP cohort, those that did receive the preoperative carbohydrate drink trended towards a higher glucose level preoperatively (148.9 ± 80.36 mg/dL) compared to the ERP patients that did not receive the drink (122.5 ± 37.82 mg/dL, p=0.14). Postoperatively, glucose levels between drink recipients and drink non-recipients did not differ significantly, whether on postoperative day 0 (Drink: 146.4 ± 36.09 mg/dL vs. No Drink: 145.5 ± 39.46 mg/dL, p=0.93), postoperative day 1 (Drink: 155.3 ± 36.45 mg/dL vs. No Drink: 168.2 ± 48.28 mg/dL, p=0.28), or postoperative day 3 (Drink: 123.3 ± 38.93 mg/dL vs. No Drink: 127.9 ± 37.89 mg/dL, p=0.67) (Figure 3).

Table 3 –

Perioperative glucose in enhanced recovery and traditional pathway patients.

	ERP	TP	P-value
POD0 Glucose (mg/dL)	162.6 ± 43.8	171.4 ± 37.4	0.27
POD1 Glucose (mg/dL)	145.7 ± 37.7	152.8 ± 48.1	0.38
POD3 Glucose (mg/dL)	125.9 ± 38.0	128.5 ± 34.7	0.71

Continuous variables are presented as mean ± standard deviation.

Figure 3 –

Preoperative ERP carbohydrate drink does not significantly impact perioperative glucose. POD: Postoperative Day.

Chronic Peripheral Arterial Disease Subgroup Analysis

Given the significant number of emergent cases and acute limb ischemia indication in the TP cohort, subgroup analysis was conducted of only patients undergoing elective or urgent LEAB for claudication, rest pain, or tissue loss (TP cohort: 23 patients, ERP cohort: 48 patients). Compared to the traditional pathway, patients undergoing ERP had no significant differences in patient age (73 vs. 71 years), sex (25% vs. 35% female), race (56% vs. 43% white), BMI (28 vs. 27), smoking status (90% vs. 74% current or former smokers) , or preoperative hemoglobin A1c (7.5 vs. 7.2)were identified. Evaluation of operative case characteristics revealed similar rates of infrageniculate target and EBL, though operative time was slightly shorter in the ERP cohort (ERP: 346.3 ± 97.6 vs. TP: 400.0 ± 105.0 minutes, p=0.037). Subgroup analysis revealed a continued benefit of the ERP on both total LOS (ERP: 7.4 ± 5.8 vs. TP: 11.3 ± 7.0 days, p=0.014) and postoperative LOS (ERP: 5.8 ± 4.3 vs. TP: 8.8 ± 5.6 days, p=0.015) (Figure 4). No significant difference was detected in rates of unplanned reoperation (ERP: 8.33% vs. TP: 21.74%, p=0.14), unplanned readmission (ERP: 14.58% vs. TP: 17.39%, p=0.74), or 30-day mortality (ERP: 2.08% vs. TP: 0%, p>0.99) (Figure 4).

Figure 4 –

Enhanced recovery pathway improves length of stay in non-emergent procedures for chronic peripheral artery disease. ERP: Enhanced Recovery Pathway. TP: Traditional Pathway. LOS: length of stay

Enhanced Recovery Pathway Compliance

Implementation of the ERP influenced compliance with both novel and preexisting perioperative process measures with a goal compliance of greater than 80% for each process measure (Table 2). We found the most challenging elements to implement were those in the preoperative phase, primarily since order sets in the electronic medical record are not utilized regularly in this phase of care. The most successful preoperative elements included ERP-specific patient education and nutritional screening (81.67% ERP vs. 17.31% TP group, p < 0.0001) and the use of chlorhexidine wash for surgical site infection prevention (80.00% ERP vs. 40.38% TP, p < 0.001). Preoperative carbohydrate drink fell below the 80% goal at 58.33% (n = 35), and compliance was similar for patients in the outpatient setting as those in the inpatient setting (51.43% outpatient vs. 48.57% inpatient, p>0.99). Although compliance for preoperative and intraoperative acetaminophen administration also fell below the 80% goal, patients designated as ERP were still significantly more likely to receive prophylactic acetaminophen (Table 2).

We had greater success in achieving compliance with postoperative elements, primarily since these process measures were driven by editing the preexisting postoperative LEAB order set with a version that supported the ERP. As a result, many TP patients had high compliance with these measures as well (Table 2). It is worth noting that postoperative protein supplementation was not prechecked in the order set, and as a result, compliance was the poorest with this measure (28.33% ERP vs. 36.54% TP, p=0.42). However, despite the benefits of electronic medical record integration, there were several postoperative process measures that were significantly better amongst patients in the ERP.

The initiation of a clear liquid diet on postoperative day 0 was also significantly higher in the ERP group at 80.00% (n = 48) compared to the TP group at 57.69% (n = 30) (p = 0.014). By postoperative day 1, a significant number of patients in the ERP group had advanced to a solid diet (98.33%, n = 59) as opposed to the TP group (82.69%, n = 43) (p = 0.0055). Along with early diet, discontinuation of IV fluids on postoperative day 1 was more frequently accomplished in the ERP group at 95.00% (n = 57) compared to the TP group at 76.92% (n = 40) (p = 0.010). While not statistically significant, there was a trend toward improved mobilization with physical and occupational therapy on postoperative day 1 in the ERP group at 90.00% (n = 54) versus the TP group at 76.92% (n = 40) (p = 0.074).

DISCUSSION

Enhanced recovery paradigms have gained significant traction in the perioperative management of patients undergoing major abdominal surgery, including colorectal, gastric, hepatobiliary, and pancreatic surgery.¹⁶ In the general surgery specialties, ERAS is associated with decreased length of stay, readmissions, mortality, and facilitates earlier recovery of major milestones such as return of bowel function and tolerance of diet.¹⁷ Similarly, ERAS protocols have also been widely implemented for lower extremity orthopedic surgery, particularly in elective hip and knee arthroplasty.¹⁸ Appropriately, additional emphasis has been placed on patient functional status such as early ambulation or degree of participation with physical therapy.¹⁹ In contrast, ERAS protocols for vascular operations have remained sparse and only recently have consensus statements been released by the ERAS society and the SVS.^7,20,21 Though the principles of gastrointestinal or orthopedic ERAS protocols can be applied to vascular surgeries, the management of patients undergoing LEAB presents some unique challenges to ERAS implementation. Comorbid conditions and the acuity of patients undergoing LEAB certainly differs from elective joint reconstruction. And while ERAS protocols have been developed for emergency abdominal surgery, there remains an obvious anatomic discrepancy.¹⁷ Our study highlights the development of an ERP specific to the complex vascular surgery population undergoing LEAB, including patients undergoing interventions for urgent and emergent indications. Although there were some barriers to implementation in patients presenting with high acuity, we did demonstrate implementation of an ERP is feasible in both elective and non-elective settings, improving compliance with process measures, and reducing LOS and unplanned reoperations.

Development of an ERP remains highly context-dependent and must integrate numerous stakeholders in its design and implementation. At times, the success of an ERP is more contingent on a supportive culture rather than the exact components alone.²² The specific preoperative, intraoperative, and postoperative elements are thus reflective of the individual hospital or hospital system and its respective stakeholders. As evidence of institution-specific differences, Witcher et al. have previously described their own experience with development of an ERP for LEAB at their institution (University of Alabama (UAB)).⁸ In comparison to our ERP, major differences included the use of a fascia iliaca block, preoperative celecoxib, a formal tobacco cessation team in addition to other small programmatic elements. Likewise, each institution may face different barriers as Witcher et al. reported challenges with early postoperative mobilization (47%) but excellent preoperative carbohydrate supplementation (83%). In contrast, early postoperative mobilization was an early success of our ERP (90%), but carbohydrate supplementation was a significant barrier (58%). Nevertheless, our measures of improvement closely mirrored their experience with reductions in total LOS (NMH: 7.8 days, UAB: 8.3 days) and rates of readmission (NMH: 13.3%, UAB: 7.0%). These findings further highlight the multidisciplinary and multimodal aspects of ERP, and both our successes are likely reflective of an aggregate of interventions rather than one single element.

This aggregate nature of ERP implementation may contribute to the gaps in optimization of specific ERP elements. As evidenced by the 2023 ERAS/SVS Consensus Statement on Lower Extremity Bypass, only 11 of the 36 practice guidelines were based on high-quality evidence with particular deficits in optimal prehabilitation, carbohydrate loading, pre-anesthetic sedatives and analgesia, early mobility, and post-discharge instructions.⁷ Specific to carbohydrate loading, our study sought to evaluate the potential for postoperative hyperglycemia yet found no significant difference on postoperative day 0, 1, or 3 between ERP and TP patients. Prior investigations of non-vascular surgery have found carbohydrate loading to be largely safe or beneficial, though some have suggested postoperative hyperglycemia may be potentially associated with complications.^23–25 Thus, while our findings indicate our particular strategy does not induce marked hyperglycemia, the optimal protocol and patient population to receive preoperative carbohydrate loading continues to lack strong evidence. Additional lines of research to address these gaps in understanding the optimal ERP remain critically needed.

Our study is not without limitations. Chiefly, initiation of the ERP pathway required active communication from the attending surgeon, particularly in the initial phase of implementation. As a result, patients who received the majority of the ERP elements (ERP cohort) were significantly different from those that did not receive the majority of the ERP process measures (TP cohort). For example, the ERP patients were more likely to be outpatient, elective, and less likely to have acute limb ischemia when compared to the TP patients. Further, although the case complexity as measured by operative time and proportion of infrageniculate target were similar, the TP patients had significantly higher intraoperative blood loss. Therefore, while it is possible that some of the improved outcomes were secondary to improved compliance with process measures in the ERP group, it is also likely that patient and procedural factors played a role in longer length of stay and higher return to the OR in the TP group. To address this limitation and minimize the impact on acute limb ischemia and emergent procedures on postoperative outcomes, we did perform a subgroup analysis of patients undergoing only elective or urgent LEAB for claudication, rest pain or tissue loss on. After limiting the cohort to patients with chronic PAD, patients in the ERP still had significantly reduced total and postoperative LOS. Our study also lacks an evaluation of cost as a component of developing the ERP. And while ERP patients demonstrated reduced LOS, if this is indeed cost-efficient remains unknown. Lastly, despite implementation of the ERP across multiple hospitals in the Northwestern Central Region, our study presents only the results from NMH, a quaternary referral center. An analysis of the ERP across the region and other variably resourced hospitals is needed to determine the reproducibility of our findings. Despite these limitations, our early experience in developing a vascular surgery specific ERP and observed patient benefit are highly encouraging and lay the foundation for future improvements at our institution.

CONCLUSION

In summary, we describe the development and implementation of an ERP for a complex vascular surgery population undergoing LEAB at a single institution. Important considerations include the participation by multiple stakeholders across the system for both process measure development and establishment of culture for longitudinal success. Notably, our investigation included patients undergoing LEAB for any indication with a high rate of infrageniculate targets, highlighting the feasibility of an ERP in both elective and non-elective settings. Implementation of the ERP was associated with improved compliance with process measures, reduced total and postoperative length of stay, and unplanned reoperation. Our findings support the continued development of the ERP for LEAB and additional vascular surgeries at our institution. Lastly, our study provides another framework for ERP development to a growing body of ERAS protocols specific to the vascular surgery population.

ARTICLE HIGHLIGHTS.

Type of Research:

Single-center prospective cohort study

Key Findings:

Development of an enhanced recovery pathway (ERP) for lower extremity arterial bypass (LEAB) is detailed with an emphasis on stakeholder engagement and implementation across a healthcare system. Implementation of the ERP was associated with improved compliance with process measures, reduced length of stay, and unplanned reoperation.

Take Home Message:

Our results highlight the benefit of an ERP for a complex vascular surgery patient population undergoing LEAB.