What is the risk of rupture for type II endoleaks?

One discussion last week included the risk of rupture with type II endoleaks.

Reference: Brown A, et al. Type II endoleaks: challenges and solutions. Vascular Health Risk Management. 2016;12:53-63.

Summary:  Although type II endoleak appears to be associated with sac expansion (volume changes), the significance of this expansion on risk of aneurysm rupture remains unclear.

Wyss et al found a significant association between sac expansion and rupture.Twenty-seven ruptures occurred in an EVAR population of 848 patients, with an average follow-up of 4.8 years. Sixty-three percent of these ruptures occurred more than 30 days post-repair and were associated with prior complications detected on follow-up imaging. Five of these 17 ruptures demonstrated evidence of type II endoleak with associated sac expansion (four were isolated type II endoleaks and one was associated with a concomitant type Ib endoleak).

Conversely, other authors have shown no correlation. Van Marrewijk et al demonstrated that sac expansion was significantly associated with type II endoleaks; however, there was no correlation with rupture or increase in aneurysm-associated mortality. A recent systematic review reported a low incidence of rupture in patients with isolated type II endoleaks (under 1%) of which 57% were associated with sac expansion.

Sac expansion may therefore be a poor marker of risk in this population of patients; however, we do not currently have a more sensitive way of monitoring risk of rupture. As such, some authors suggest that consideration should be given to prevention of/or treatment for type II endoleak.

Pro vs Con: thrombolysis for submassive PE

One discussion this week included thrombolysis for submassive PE.

References: Howard LS. Thrombolytic therapy for submassive pulmonary embolus? PRO viewpoint. Thorax. 2014 Feb;69(2):103-105.

Simpson AJ. Thrombolysis for acute submassive pulmonary embolism: CON viewpoint. Thorax. 2014 Feb;69(2):105-107.

Summary:  The normotensive patient with confirmed pulmonary embolism (PE) and right ventricular (RV) dilatation presents a significant dilemma to clinicians. On one hand, a string of publications have demonstrated that RV dysfunction is associated with adverse outcomes in patients with PE; on the other, thrombolysis carries a significant risk of bleeding. The real problem of course (and part of the reason for having this important debate) is that we have no reliable and accurate tools to pinpoint the important minority of patients with submassive PE who genuinely might benefit from thrombolysis or perhaps from surgical embolectomy

PRO: In proposing the argument that submassive PE should be treated with thrombolysis, we must first accept that direct mortality due to the PE itself, not confounding conditions, remains unacceptably high with anticoagulation alone. A more aggressive strategy is required. As long as the benefits of thrombolysis outweigh the risks, then thrombolysis offers the best currently available approach. When this is coupled with the further benefits of likely reduction in CTEPH, the case becomes even stronger.

Outcomes in patients with true submassive PE remain unacceptably high and thrombolysis has been shown to improve surrogate outcomes for mortality as well as long-term complications. The risks from thrombolysis are low, and when reduced doses are used, evidence so far suggests no decrease in benefit, but a further reduction in bleeding.

CON: The emerging picture is that, at the point of presentation, patients with submassive PE are highly likely to survive if treated with heparin alone and that the associated RV dilatation is likely to resolve spontaneously in the significant majority. The nagging doubt, of course, surrounds the small proportion of patients who will have persistent RV dysfunction, particularly as this group seems vulnerable to recurrent venous thromboembolism (VTE).

However attractive it may be theoretically, we have no strong evidence to inform whether early thrombolysis can reduce VTE recurrence—we know that longer-term anticoagulation does. Similarly, we have no evidence that early thrombolysis reduces the risk of CTEPH, yet modern treatments significantly improve outcomes for this important
complication. So, instead of early thrombolysis, why not repeat echocardiography at 3 months, prolong anticoagulation in those with persistent RV impairment and assess carefully for evidence of CTEPH in the ensuing period?

Please see the full text of these editorials (linked above in references) for the full argument and citations. 

Have you heard of the PESI score?

One discussion this week included the application of the Pulmonary Embolism Severity Index (PESI) score.

Reference: Aujesky D. Pulmonary Embolism Severity Index (PESI) [online calculator]. Retrieved from https://www.mdcalc.com/pulmonary-embolism-severity-index-pesi

Summary: WHEN TO USE: In the setting of a patient diagnosed with PE, the PESI can be utilized to determine mortality and long term morbidity.

PESI2

PEARLS/PITFALLS: PESI is a risk stratification tool that has been externally validated to determine the mortality and outcome of patients with newly diagnosed pulmonary embolism (PE).

In the setting of a patient with renal failure or severe comorbidities, clinical judgement should be used over the PESI, as these patients were excluded in the validation study.

  • The PESI score determines risk of mortality and severity of complications.
  • The score does not require laboratory variables.
  • It is meant to aid in decision making, not replace it. Clinical judgement should always take precedence.
  • The PESI score determines clinical severity and can influence treatment setting for management of PE.
    • Class I and II patients may possibly be safely treated as outpatients in the right clinical setting.

Go to MD Calc for the calculator below:

PESI

 

Additional Reading: Aujesky D, et al. Derivation and validation of a prognostic model for pulmonary embolism. American Journal of Respiratory and Critical Care Medicine. 2005 Oct 15;172(8):1041-1046.

Emory authors: Perioperative hyperglycemia management

One discussion this week included management of perioperative hyperglycemia.

Reference: Duggan EW, Carlson K, Umpierrez GE. Perioperative hyperglycemia management: an update. Anesthesiology. 2017 Mar;126(3):547-560. doi: 10.1097/ALN.0000000000001515.

Summary:  A substantial body of literature demonstrates a clear association between perioperative hyperglycemia and adverse clinical outcomes. The risk for post-operative complications and increased mortality relates to both long-term glycemic control and to the severity of hyperglycemia on admission and during the hospital stay. This study reports on the prevalence, diagnosis and pathophysiology of perioperative hyperglycemia and provides a practical outline for the management of surgical patients with diabetes and hyperglycemia.

The sections addressed include:

  • Metabolic consequences of surgical stress and anesthesia
  • Prevalence of hyperglycemia and diabetes in surgical patients
  • Preoperative period
  • Diabetes, fasting and feeding
  • Intraoperative period
  • Postoperative period
  • Glycemic targets
  • Pre-operative glycemic management
  • Intraoperative glycemic management
  • Post-operative glycemic management for non-ICU patients
  • Transitioning from IV to SC insulin
  • Insulin pump therapy
  • Hypoglycemia
  • Glucose monitoring in the perioperative period

CONCLUSION: Hyperglycemia is common in surgical patients. Current data demonstrates an association between elevated BG and a risk of perioperative complications in diabetic and non-diabetic patients. Insulin administration intra- and post-operatively has been shown to improve clinical outcomes. Individual patient characteristics and surgical case factors are considered when choosing subcutaneous insulin or an insulin infusion. Both are appropriate options on the day of surgery. Blood glucose values of 180 mg/dL (10 mmol/L) or higher are treated with insulin. Target range for the perioperative period is 140-180 mg/dL (7.7-10 mmol/L). Post-operatively, surgical floor patients with poor or uncertain oral intake are treated with once daily basal insulin. Prandial insulin is added when patients tolerate oral intake. Increasing evidence suggests a role for incretin therapy during the peri-operative period in patients with type 2 diabetes.

Multiple teams care for a surgical patient during the hospital course (anesthesiology, surgery, critical care medicine, internal/hospital medicine and endocrinology). Therefore, multidisciplinary groups within an institution should work together to create appropriate protocols for hyperglycemia screening, monitoring and treatment to minimize errors and to better care for patients.

Are diabetic patients at greater risk for anastomotic leaks and mortality when undergoing colectomies?

One discussion this week included postoperative anastomotic leaks.

Reference: Ziegler MA, et al. Risk factors for anastomotic leak and mortality in diabetic patients undergoing colectomy: analysis from a statewide surgical quality collaborative. Archives of Surgery. 2012 Jul;147(7):600-605. doi: 10.1001/archsurg.2012.77.

Summary: In a database review of patients in Michigan who underwent colectomy, the study aimed to determine risk factors in diabetic patients that are associated with increased postcolectomy mortality and anastomotic leak.

Primary risk factors were diabetes mellitus, hyperglycemia, steroid use, and emergency surgery. Of the 5123 patients, 889 were diabetic, 4234 were nondiabetic.

Diabetes alone was not found to be a risk factor for anastomotic leak in this study.

  • 56% of diabetic patients had preoperative glucose levels of 140 mg/dL or higher
  • Preoperative steroid use led to increased rates of anastomotic leak in diabetic patients
  • Diabetic patients who had a leak had more than a 4-fold higher mortality (26.3% vs 4.5%, P<.001) compared with nondiabetic patients (6.0% vs 2.5%, P<.05).
  • Mortality was associated with hyperglycemia for nondiabetic patients only

The authors conclude that improved screening may identify high-risk patients who would benefit from perioperative intervention.

Foreign body removal without hospitalization: a new use for a stent removal device

One discussion this week involved the removal of foreign bodies.

Reference: Smith PM, et al. Isiris: a novel method of removing foreign bodies from the lower urinary tract to avoid unnecessary hospitalization and anesthesia. Journal of Endourology Case Reports. 2016 Aug 1;2(1):144-147. doi: 10.1089/cren.2016.0086.

Summary: Polyembolokoilamania refers to the practice of inserting foreign bodies (FBs) into natural orifices. A FB within the urethra is a relatively rare phenomenon with 646 cases recorded last year in the United Kingdom. Management of these patients presents technical challenges and complexities because of underlying psychiatric disorders that are often associated. This case illustrates a novel way of removing FBs from the genitourinary tract, requiring less resources, preventing hospital admission, and attempts to break the cycle of behavior, leading to recurrent attendance with polyembolokoilamania.

A 38-year-old Caucasian male prisoner, with psychiatric history presented to the emergency department (ED) with a history of inserting FBs into his urethra on 12 different occasions over a 6-week period. Of these 12 attendances, 3 resulted in admission and 2 required emergency intervention in theater under general anesthesia. After the third attendance in 5 days, it was decided to use Isiris™, a single-use flexible cystoscopy device with a built-in ureteral stent grasper, to remove the FBs and check the integrity of the urethra. The procedure was performed within the ED, without the need for admission to a ward bed or general anesthesia. Furthermore, only two members of staff were required to remove all of the urethral FBs.

Isiris, although marketed as a stent removal device, enabled us to remove all the patient’s FBs in one procedure. Isiris is an easy to use device, similar to a flexible cystoscope, that a specialist nurse or resident would be familiar using. It allows efficient and safe removal of lower urinary tract FBs, even out of hours. It requires minimal staffing support and can be done in the ED. It has the potential to reduce associated sequela of urethral polyembolokoilamania, saving resources while preserving the availability of the emergency theater.

Outcomes of and predictors for bowel ischemia after AAA repair: a study of 7312 patients

One discussion this week included AAA repair. The article cited here was provided by the chief resident.

Reference: Ultee KH, et al. Incidence of and risk factors for bowel ischemia after abdominal aortic aneurysm repair. Journal of Vascular Surgery. 2016 Nov;64(5):1384-1391. doi: 10.1016/j.jvs.2016.05.045.

Summary: Bowel ischemia is a rare but devastating complication after abdominal aortic aneurysm (AAA) repair. Its rarity has prohibited extensive risk-factor analysis, particularly since the widespread adoption of endovascular AAA repair (EVAR); therefore, this study assessed the incidence of postoperative bowel ischemia after AAA repair in the endovascular era and identified risk factors for its occurrence

METHODS: A total of 7312 patients undergoing intact or ruptured AAA repair in the Vascular Study Group of New England (VSGNE) January 2003 – November 2014 were included. Patients with and without postoperative bowel ischemia were compared and stratified by indication (intact and ruptured) and treatment approach (open repair and EVAR). Criteria for diagnosis were endoscopic or clinical evidence of ischemia, including bloody stools, in patients who died before diagnostic procedures were performed. Independent predictors of postoperative bowel ischemia were established using multivariable logistic regression analysis.

RESULTS: Postoperative outcomes (p.1389):

AAA repair

RESULTS: Predictors of bowel ischemia after AAA repair (p.1390):

AAA predictors

CONCLUSIONS: The authors state that “these date should be considered during operative planning in an effort to adequately assess patient risk for bowel ischemia and undertake efforts to reduce it” (p.1391).

Can vein diameter predict arteriovenous fistula maturation?

One discussion this week included the relationship between vein size and fistula failure.

Reference: Bashar K, et al. The role of venous diameter in predicting arteriovenous fistula maturation: when not to expect an AVF to mature according to pre-operative vein diameter measurements? A best evidence topic. International Journal of Surgery. 2015 Mar;15:95-99. doi: 10.1016/j.ijsu.2015.01.035.

Summary: This best evidence topic was investigated according to a described protocol, and asked the question: what is the minimal vein diameter that can successfully predict maturation of an arteriovenous fistula (AVF) in patients undergoing dialysis?

The search retrieved 804 papers, of which 5 represented the best evidence to answer the clinical question. All studies assessed the association between successful AVF maturation and the size of vein used.

Highlighted findings:

  1. The strongest evidence came from a non-randomised controlled follow-up study in which 76% of fistulas created using >2 mm cephalic vein successfully matured compared to 16% when the vein measured ≤2 mm.
  2. Another prospective, multicentre study showed 65% successful maturation using veins >4 mm compared to 45% with veins < 3 mm. Vein diameter was found to be an independent predictor of maturation in multivariate regression analysis in two retrospective observational studies.
  3. A retrospective observational study found that using venous measurements of ≥2.5 mm following tourniquet application resulted in more fistulas been created that would have otherwise been denied based on venous ultrasound mapping.
  4. Routine use of tourniquet makes it possible to form AVFs in patients who otherwise would have been rejected. One study showed good results from using a transposed BBAVF when a BCAVF was deemed inappropriate following US.

In conclusion, a vein diameter of <2.5 mm should be considered inadequate for formation of an AVF, particularly if those measurements remain unchanged following the use of tourniquet.

What are the rates of major and minor bleeding complications after pharmacologic DVT prophylaxis?

One discussion this week included the rate of bleeding complications after pharmacologic DVT prophylaxis.

Reference: Leonardi MJ, McGory ML, Ko CY. The rate of bleeding complications after pharmacologic deep venous thrombosis prophylaxis: a systematic review of 33 randomized controlled trials. Archives of Surgery. 2006 Aug;141(8):790-797.

Summary: In a systematic review of 33 RCTs with 33,813 patients, Leonardi et al (2006) concluded that there is a small, but measurable, rate of minor bleeding complications associated with pharmacologic DVT prophylaxis: injection site bruising (6.9%), wound hematoma (5.7%), drain site bleeding (2.0%), and hematuria (1.6%).

The rate of major complications, such as GI tract (0.2%) or RP (<0.1%) bleeding, was extremely low in this review. Complications requiring a change in care, such as subsequent operation (0.7%) or discontinuation of prophylaxis (2.0%), were also infrequent. The subsequent operation rate for bleeding problems for pharmacologic prophylaxis vs placebo was identical, at 0.7%.

dvt

(p.795)

Additional Reading: Leonardi MJ, McGory ML, Ko CY. A systematic review of deep venous thrombosis prophylaxis in cancer patients: implications for improving quality. Annals of Surgical Oncology. 2007 Feb;14(2):929-936.

The STITCH trial: a summary

One discussion this week mentioned the STITCH trial.

Reference: Deerenberg EB, et al. Small bites versus large bites for closure of abdominal midline incisions (STITCH): a double-blind, multicentre, randomised control trial. Lancet. 2015 Sep 26;386(10000):1254-1260. doi: 10.1016/S0140-6736(15)60459-7.

Summary: Incisional hernia is a frequent complication of abdominal operations with an incidence of 10–23%, which can increase to 38% in specific risk groups. It is associated with pain and discomfort, resulting in a decreased quality of life. Incarceration and strangulation of abdominal contents can take place, for which emergency surgery is indicated, with associated morbidity and mortality. The authors (2015) estimate about 348,000 operations for incisional hernia are done every year in the US with $3.2 billion in annual associated costs.

This trial is registered at Clinicaltrials.gov, number NCT01132209 and with the Nederlands Trial Register, number NTR2052.

METHODS: The STITCH trial was a prospective, multicentre, double-blind, randomised controlled trial conducted at surgical and gynaecological departments in 10 hospitals in the Netherlands between October 2009 – May 2012. The 560 patients who were scheduled to undergo elective abdominal surgery with midline laparotomy were randomly assigned to receive small tissue bites of 5 mm every 5 mm or large bites of 1 cm every 1 cm.  The primary outcome was the occurrence of incisional hernia; a reduced incidence in the small bites group was expected

RESULTS: Patients in the small bites group had fascial closures sutured with more stitches than those in the large bites group (mean number of stitches 45 [SD 12] vs 25 [10]; p<0.0001), a higher ratio of suture length to wound length (5.0 [1.5] vs 4.3 [1.4]; p<0.0001) and a longer closure time (14 [6] vs 10 [4] min; p<0.0001). At 1 year follow-up, 57 (21%) of 277 patients in the large bites group and 35 (13%) of 268 patients in the small bites group had incisional hernia (p=0.0220, covariate adjusted odds ratio 0.52, 95% CI 0.31-0.87; p=0.0131). Rates of adverse events did not differ significantly between groups.

CONCLUSIONS: In this study, the small bites suture technique is more effective than the traditional large bites technique for prevention of incisional hernia in midline incisions and is not associated with a higher rate of adverse events. The small bites technique should become the standard closure technique for midline incisions.