Prospective Study of Postoperative Glycemic Control with a Standardized Insulin Infusion Protocol after Infrainguinal Bypass and Open Abdominal Aortic Aneurysm Repair

Preoperative HbA1c and Outcomes Following Lower Extremity Vascular Procedures

OBJECTIVES

Limited data exist evaluating pre-operative hemoglobin A1c (HbA1c) in patients undergoing vascular procedures for peripheral arterial disease (PAD). This study evaluated the relationship of preoperative HbA1c on outcomes after open and endovascular lower extremity (LE) vascular procedures for PAD.

METHODS

We selected patients with PAD admitted for elective LE procedures between September 2008 and December 2015 from the Cerner Health Facts® database using ICD-9-CM diagnosis and procedure codes. Bivariable analysis and multivariable logistic models examined the association of patient characteristics, procedure type, and preoperative HbA1c (normal < 6.5%, high ≥ 6.5%) with postsurgical outcomes that included infection, renal failure, respiratory or cardiac complications, length of stay (LOS), in-hospital mortality, and readmission.

RESULTS

Of 4,087 patients who underwent a LE vascular procedure for PAD, 2,462 (60.2%) had a preoperative HbA1c recorded. The cohort was mostly male (60%), white (73%), and underwent endovascular intervention (77%). Patients with high HbA1c levels were more likely of black race (p < .02) and had significantly higher comorbidities (p < .0001). Elevated HbA1c was associated with diabetes (p < .0001) and cellulitis (p = .05) on unadjusted analysis. Multivariable logistic regression (adjusting for patient, hospital, comorbidity and procedural characteristics) revealed that elevated HbA1c was significantly associated with 30-day readmission (OR = 1.06, 95% CI = 1.00-1.12), but was not associated with the other outcomes. An independent diagnosis of diabetes was not predictive of complications or readmission.

CONCLUSIONS

Historic glucose control, as evidenced by a high preoperative HbA1c level, is not associated with adverse outcome, other than readmission, in patients undergoing LE procedures for PAD. Given the known association of high perioperative glucose levels with poor outcome following vascular procedures, this is suggestive of a more important effect of perioperative, as opposed to chronic, glucose control upon outcome. Thus, we suggest focusing efforts on creating standardized goal-directed guidelines for glucose control in the perioperative period for LE vascular procedures to potentially mitigate complications.

How to Prevent Surgical Site Infection in Vascular Surgery: A Review of the Evidence

BACKGROUND

This review aims to identify and review the current evidence for preventing postoperative surgical site infections in abdominal aortic aneurysm surgery or infrainguinal arterial surgery.

METHODS

Extended literature review of clinical trials that examined the prevention of postoperative surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. Searches were conducted on Ovid MEDLINE (1950 - 13 March 2020) using key terms for vascular surgery, surgical site infections and specific preventative techniques. Articles were included if they discussed a relationship between a preventative technique and surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. The GRADE guidelines were used to assess the quality of evidence.

RESULTS

21 techniques and 81 studies were included. Prophylactic antibiotics and negative pressure wound therapy have a high quality of evidence for the prevention of surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. A moderate quality evidence base was identified for gentamicin containing collagen implant (confined to high surgical site infection risk centers). Currently, there is a low or very low quality of evidence to suggest a reduction in the surgical site infection rate for combination therapy, glycaemic control, Methicillin-resistant Staphylococcus aureus screening and absorbable suture. Evidence suggests no beneficial effect for nutritional supplementation, chlorhexidine bath, hair removal therapy, Staphylococcus aureus nasal eradication, cyanoacrylate microsealant, silver grafts, rifampicin bonded grafts, triclosan coated suture and postoperative wound drains. Endoscopic saphenous vein harvest may reduce surgical site infection rate (very low quality of evidence) but may lower long-term patency. Autologous vein grafts may increase surgical site infections (very low quality of evidence) but may provide better long-term patency rates in above-knee infrainguinal bypass surgery. There was no identified evidence for perioperative normothermia, electrosurgical bipolar vessel sealer or Dermabond and Tegaderm for surgical site infection prevention in vascular surgery.

CONCLUSIONS

Prophylactic antibiotics and postoperative negative pressure wound therapy are effective in the prevention of postoperative surgical site infection in abdominal aortic aneurysm or infrainguinal arterial surgery. There exists a significant risk of bias in the literature for many preventative techniques and further studies are required to investigate the efficacy of gentamicin containing collagen implant, and specific combination therapies.

Surgical Infection Society Research Priorities: A Narrative Review of Fourteen Years of Progress

Background: In 2006, the Surgical Infection Society (SIS) utilized a modified Delphi approach to define 15 specific priority research questions that remained unanswered in the field of surgical infections. The aim of the current study was to evaluate the scientific progress achieved during the ensuing period in answering each of the 15 research questions and to determine if additional research in these fields is warranted. Methods: For each of the questions, a literature search using the National Center for Biotechnology Information (NCBI) was performed by the Scientific Studies Committee of the SIS to identify studies that attempted to address each of the defined questions. This literature was analyzed and summarized. The data on each question were evaluated by a surgical infections expert to determine if the question was answered definitively or remains unanswered. Results: All 15 priority research questions were studied in the last 14 years; six questions (40%) were definitively answered and 9 questions (60%) remain unanswered in whole or in part, mainly because of the low quality of the studies available on this topic. Several of the 9 unanswered questions were deemed to remain research priorities in 2020 and warrant further investigation. These included, for example, the role of empiric antimicrobial agents in nosocomial infections, the use of inotropes/vasopressors versus volume loading to raise the mean arterial pressure, and the role of increased antimicrobial dosing and frequency in the obese patient. Conclusions: Several surgical infection-related research questions prioritized in 2006 remain unanswered. Further high-quality research is required to provide a definitive answer to many of these priority knowledge gaps. An updated research agenda by the SIS is warranted at this time to define research priorities for the future.

Immediate postoperative hyperglycemia after peripheral arterial bypass is associated with short-term and long-term poor outcomes

OBJECTIVE

Although the impact of poorly controlled diabetes on surgical outcomes of patients undergoing lower extremity revascularization is well-known, it is not clear if immediate postoperative hyperglycemia (IPH) itself can be used as a surrogate for poor outcomes after peripheral arterial bypass. We sought to examine the effect of IPH in this patient population with its impact on short-term and long-term outcomes.

METHODS

Retrospective review was completed for 505 patients who underwent either suprainguinal bypass surgery or infrainguinal bypass surgery between July 2002 and April 2018 for the treatment of peripheral arterial disease. All patients were undergoing first-time open bypass grafting. Patients were stratified into those who were normoglycemic or hyperglycemic (glucose ≥ 140 mg/dL) within 24 hours after surgery. A comparative analysis was performed on comorbidities and outcomes.

RESULTS

Of 505 patients who underwent bypass grafting, 255 patients (50.5%) were hyperglycemic. The mean age of patients was 63.5 ± 14.1 years. The median follow-up was 5.2 years (range, 0.0-15.2 years). The distribution of procedures was as follows: femoral to popliteal bypasses (29%), femoral to femoral bypasses (17%), femoral to tibial bypasses (12%), aortobifemoral bypasses (10%), iliofemoral bypasses (9%), and axillofemoral bypasses (7%). At 30 days, hyperglycemic patients had an increased incidence of limb loss (8.3% vs 4.0%) and myocardial infarction (4.8% vs 0.8%) and incurred higher costs of hospital stay ($27,701 vs $22,990) (all P < .05). At 10 years, these patients had a higher incidence of needing major amputations (15.4% vs 9.4%; P = .025). Hyperglycemia after infrainguinal bypass was associated with nearly twice the risk of limb loss at 5 years (hazard ratio, 1.91; P = .034). Among the cohort of patients who required major amputations, the time duration between index revascularization and amputation was significantly shorter as compared with normoglycemic patients (P = .003).

CONCLUSIONS

In this single-institution study with long-term follow-up, IPH was associated with increased rates of 30-day amputation and myocardial infarction, as well as an increased cost of hospital stay. In the long term, postoperative hyperglycemia was associated with greater major limb loss. Among the cohort of patients who required major amputations, the time period between revascularization and amputation was shorter for those patients who had IPH. IPH is an independent marker for poor outcomes after lower extremity revascularization procedures.

Association of postoperative glycemic control with outcomes after carotid procedures

Objective

There are limited data evaluating the impact of postoperative hyperglycemia in patients undergoing vascular procedures. This study evaluated the relationship between suboptimal glucose control and adverse outcomes after carotid artery stenting and carotid endarterectomy.

Methods

Patients admitted for elective carotid procedures were selected from the Cerner Health Facts® (2008–2015) database using ICD-9-CM diagnosis and procedure codes. We examined the relationship between patient characteristics, postoperative hyperglycemia (any value > 180 mg/dL), and complications with chi-square analysis. A multivariable model examined the association between patient characteristics, procedure type, and glucose control with infection, renal failure, stroke, respiratory and cardiac complications, and length of stay over 10 days.

Results

Of the 4287 patients admitted for an asymptomatic carotid procedure, 788 (18%) underwent carotid artery stenting and 3499 (82%) underwent carotid endarterectomy. Most patients (87%) had optimal postoperative glucose control (80–180 mg/dL); 13% had suboptimal glucose control. On average, patients with suboptimal glucose control experienced: higher stroke rates (6.2% vs. 2.7%; p <  0.001); more cardiac complications (5.1% vs. 2.0%; p <  0.001); longer hospital stays (3.1 vs. 1.8 days; p < .001); higher rates of post-procedure infection (4.0% vs. 1.8%; p = .001); and more complications than patients with optimal glucose control. Multivariable logistic regression demonstrated that patients with suboptimal glucose control had higher odds of having an infectious (pneumonia, cellulitis, surgical site, etc.) complication (OR 1.91, 95% CI 1.10–3.34), renal failure (OR 3.36, 95% CI 1.95–5.78), respiratory complications (OR 1.81, 95% CI 1.21–2.71), stroke (OR 1.82, 95% CI 1.15–2.88), or length of stay > 10 days (OR 4.07, 95% CI 2.02–8.20).

Conclusions

Suboptimal glucose control was associated with adverse events after carotid artery stenting and carotid endarterectomy, independent of a diabetes diagnosis. Several adverse outcomes were associated with hyperglycemia, including stroke. Given the singular role of carotid procedures in preventing stroke, we suggest that incorporating rigorous post-operative glucose control into best medical treatment of carotid disease should be considered as a standard practice.

Perioperative Management of Diabetes Mellitus: Novel Approaches

PURPOSE OF REVIEW

Several studies have demonstrated the benefits of glycemic control in the perioperative period and there is ongoing interest in development of systematic approaches to achieving glycemic control. This review discusses currently available data and proposes a new approach to the management of hyperglycemia in the perioperative period.

RECENT FINDINGS

In a recent study, we demonstrated that early preoperative identification of patients with poorly controlled diabetes and proactive treatment through various phases of surgery improves glycemic control, lowers the risk of surgical complications, and decreases the length of hospital stay. Implementation of a perioperative diabetes program that systematically identifies and treats patients with poor glycemic control early in the preoperative period is feasible and improves clinical care of patients undergoing elective surgery.

Outcomes associated with hyperglycemia after abdominal aortic aneurysm repair

OBJECTIVE

We evaluated the association between postoperative hyperglycemia and outcomes after abdominal aortic aneurysm (AAA) repair.

METHODS

We used diagnosis and procedure codes (International Classification of Diseases, Ninth Revision, Clinical Modification) to identify patients who underwent open or endovascular repair of a nonruptured AAA from September 2008 to March 2014 from the Cerner Health Facts database (Cerner Corporation, North Kansas City, Mo). We evaluated the association between postoperative hyperglycemia (glucose concentration >180 mg/dL) and infections, in-hospital mortality, readmission, patients' characteristics, length of hospital stay, and medications. Multivariable logistic models examined the association of postoperative hyperglycemia with in-hospital infection and mortality.

RESULTS

Of 2478 patients, 2071 (83.5%) had good postoperative glucose control (80-180 mg/dL), and 407 (16.5%) had suboptimal control (hyperglycemia). Patients who had postoperative hyperglycemia experienced longer hospital stays (9.5 vs 4.7 days; P < .0001), higher infection rates (18% vs 8%; P < .0001), higher in-hospital mortality (8.4 vs 1.2%; P <.0001), and more acute complications (ie, acute renal failure, fluid and electrolyte disorders, respiratory complications). After adjusting for patients' characteristics and medications, multivariable logistic regression models demonstrated that patients receiving postoperative insulin had nearly 1.6 times the odds of having an infectious complication (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.12-2.2; P = .007) than those who did not. Hyperglycemic patients had 3.5 times the odds of in-hospital mortality (OR, 3.48; 95% CI, 1.78-6.80 [P = .0003]; 2.3% vs 1.2%; P < .001). When stratified by procedure type, patients with hyperglycemia who underwent endovascular repair had nearly 2 times the odds of an infectious complication (OR, 1.85; 95% CI, 0.98-3.51; P = .05) and 7.5 times the odds of in-hospital mortality (OR, 7.54; 95% CI, 1.95-29.1; P = .003). Patients who underwent an open AAA repair and who had hyperglycemia had three times the odds of dying in the hospital (OR, 3.05; 95% CI, 1.29-7.21; P = .01).

CONCLUSIONS

Among patients undergoing elective AAA repair, approximately one in six had postoperative hyperglycemia. After AAA repair in patients with and without diabetes, postoperative hyperglycemia was associated with adverse events, including in-hospital mortality and infections. Compared with those who had open surgery, patients undergoing endovascular repair who had postoperative hyperglycemia had greater risk of infection and death. After controlling for insulin administration and postoperative hyperglycemia, a diabetes diagnosis was associated with lower odds of both infection and in-hospital mortality. Our study suggests that hyperglycemia may be used as a clinical marker as it was found to be significantly associated with inferior outcomes after elective AAA repair. This retrospective study, however, cannot imply causation; further study using prospective methods is needed to elucidate the relationship between postoperative hyperglycemia and patient outcomes.

Inpatient Glycemic Management of Non-cardiac CVD: Focus on Stroke and PVD

PURPOSE OF REVIEW

Hyperglycemia occurs frequently in hospitalized patients with stroke and peripheral vascular disease (PVD). Guidelines for inpatient glycemic management are not well established for this patient population. We will review the clinical impact of hyperglycemia in this acute setting and review the evidence for glycemic control.

RECENT FINDINGS

Hyperglycemia in acute stroke is associated with poor short and long-term outcomes, and perioperative hyperglycemia in those undergoing revascularization for PVD is linked to increased post-surgical complications. Studies evaluating tight glucose control do not demonstrate improvement in clinical outcomes, although the risk for hypoglycemia increases substantially. Additional studies are needed to evaluate tight glucose goals relative to our current standard of care and the role of permissive hyperglycemia. Given the limited data to guide glycemic management in these patient populations, it is recommended that general guidelines for inpatient glycemic control be followed. Special considerations should be made to address factors that may impact glucose management, including neurological deficits and clinical changes that occur in the postoperative state.