Lower Extremity Ischemia after Abdominal Aortic Aneurysm Repair

Editor's Choice - Prevalence of Smoking and Impact on Peri-Operative Outcomes After Elective Abdominal Aortic Aneurysm Repair

OBJECTIVE

The contemporary burden of smoking in patients undergoing elective abdominal aortic aneurysm (AAA) repair in the UK is unknown. This study aimed to quantify the prevalence of smoking in patients undergoing AAA repair in the UK and determine the association between smoking and peri-operative outcomes.

METHODS

This was an observational cohort study. The National Vascular Registry was interrogated for adults undergoing elective infrarenal AAA repair from 2014 to 2021 for prevalence of current smokers, former smokers, and non-smokers over time. The primary outcomes were post-operative complications by smoking status. Secondary outcomes were variation in smoking rates over time and by hospital, in hospital mortality, and length of stay by smoking status. All analyses were adjusted using the validated British Aneurysm Repair score.

RESULTS

Overall, 26 916 patients undergoing elective AAA repair were included (21.9% smokers, 62.2% former smokers, 15.9% non-smokers). The prevalence of smoking did not change over time, with a 2.4 fold variation between UK hospitals (range 13.0 - 31.8% excluding outliers). In hospital mortality was not significantly different between smokers, former smokers, and non-smokers (p > .050 for all comparisons). Compared with non-smokers, smoking was associated with increased overall (odds ratio [OR] 1.40, 95% confidence interval [CI] 1.24 - 1.57) and respiratory complications (OR 1.98, 95% CI 1.63 - 2.39), limb ischaemia (OR 1.63, 95% CI 1.19 - 2.23), bowel ischaemia (OR 1.64, 95% CI 1.06 - 2.54), return to theatre (OR 1.38, 95% CI 1.11 - 1.71), and intensive care admission (OR 1.43, 95% CI 1.31 - 1.56). Compared with former smokers, smoking was associated with increased overall (OR 1.24, 95% CI 1.14 - 1.36), respiratory (OR 1.44, 95% CI 1.27 - 1.63) and limb ischaemia complications (OR 1.48, 95% CI 1.19 - 1.84), and intensive care admission (OR 1.37, 95% CI 1.28 - 1.46). On analysis of the endovascular aneurysm repair subgroup, active smoking was associated with significantly higher rates of limb ischaemia compared with former and non-smokers (OR 2.12, 95% CI 1.49 - 3.01 and OR 1.94, 95% CI 1.19 - 3.16 respectively).

CONCLUSION

The prevalence of smoking remains high in patients undergoing elective AAA repair with no evidence of a decline in active smokers from 2014 to 2021 compared with the general UK population. Smoking is associated with increased peri-operative complication rates.

Intraoperative calf blood pressure measurements for the detection of early lower extremity ischemia following endovascular aneurysm repair

BACKGROUND

Access vessel complications during endovascular aneurysm repair (EVAR) remain a concern and has been reported to occur in 3-10% of cases. The purpose of this study is to report our experience with intraoperative, non-invasive calf blood pressure (BP) measurements and ankle brachial indexes (ABIs) before and immediately following EVAR, in evaluating the perfusion of the lower extremities and detecting early lower extremity ischemia (LEI).

METHODS

We performed a retrospective review of all consecutive patients who underwent EVAR at our institution between the years 2019 and 2021. All patients had blood pressure cuffs placed on their calves prior to the procedure. Calf BP measurements and ABIs were obtained prior to and immediately after the surgery. Based on the BP measurements, patients were categorized into two groups. Group 1: patients with unchanged ABIs at the end of the procedure. Group 2: patients who experienced a decrease in ABIs at the end of the procedure (no BP obtained or decrease of ABI >0.3 from preoperative measurement). Patients in group 2 underwent exploration of the access vessel. Based on these, the positive and negative predictive values of the study were calculated.

RESULTS

During the study period we performed 113 EVAR procedures for abdominal, thoracic, and thoracoabdominal aortic aneurysms, in which 226 femoral arteries were accessed. Mean age was 71 years and 88% were males. In 219 (97%) of the limbs, there was no change in calf BP measurements and ABIs immediately after the procedure, when compared to the preoperative measurements, and none suffered a decrease in follow up ABIs. In 7 limbs (3%), there was a decrease in the calf BP (group 2), and all underwent exploration of the femoral artery. In 5 of these, a pathology was found within the artery. The positive predictive value of the intraoperative calf BP measurement was 71%. The negative predictive value of the study was 100%.

CONCLUSION

Intraoperative calf BP and ABIs is a simple method to assess the lower limb perfusion and detect LEI following EVAR. The exam is particularly accurate in ruling out LEI as it has a very high negative predictive value. However, an abnormal measurement does not necessarily confirm LEI.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Critical Care of the Vascular Surgery Patient

Patients that require major vascular surgery suffer from widespread atherosclerosis and have multiple comorbidities that place them at increased risk for postoperative complications and require admission to the intensive care unit (ICU). Postoperative critical care of these patients is focused on hemodynamic optimization, and early identification and management of complications to improve outcomes.

Acute aortobiliac graft thrombosis

Introduction and Importance

Acute limb ischemia after infrarenal aortic repair is a rare complication, which in mainly described to appear in a short time after surgery.The aim of this paper is to describe a case of a 66-year-old woman who presented at out attention with acute right limb ischemia, one year later an aortic repair for acute abdominal aortic aneurysm rupture. In the best of our knowledge there are no cases of sudden graft occlusion after such long time, described in literature.

Case presentation

Patient presented with sudden pain and pallor in the right lower limb and subsequently same symptoms to the left lower limb. One year before she underwent an emergency repair for abdominal aortic aneurysm rupture with an aortobiliac graft. Computed Tomography Angiography (CTA) scan showed a complete occlusion of the infrarenal aorta, including aortoiliac graft, to the common bilateral iliac arteries. On the right side was also found a complete occlusion of the popliteal artery.Emergent embolectomy of the right popliteal artery via the femoral artery was performed.

Clinical discussion

CTA scan performed on third post-operative day showed the patency of infrarenal aorta and aortic portion of the grafts in presence of floating thrombus, right iliac branch patency and chronic occlusion of left iliac branch. A kinking of both graft iliac branches was evident after this CTA scan. CTA scan at one month demonstrated resolution of the thrombosis of the infrarenal aorta, complete patency of aortic portion of the graft and right iliac branch and chronic obstruction of the left common iliac artery.

Conclusion

Acute limb ischemia caused by sudden graft occlusion one year later an aortic repair for acute abdominal aortic aneurysm rupture is a very rare event. Graft limbs kinking could explain acute thrombosis of the graft.

Contemporary mortality after emergent open repair of complex abdominal aortic aneurysms

OBJECTIVE

Mortality after open repair for emergent complex abdominal aortic aneurysm (AAA) is poorly defined. This study evaluated the 30-day mortality of open complex AAA repair performed for rupture or other emergent indication using a national surgical registry. We subsequently identified factors associated with mortality.

METHODS

The targeted vascular module from the American College of Surgeons National Surgical Quality Improvement Program was queried to identify patients undergoing open repair for juxtarenal and suprarenal AAAs or type IV thoracoabdominal aneurysms (TAAAs) for rupture or other emergent indication from 2011 to 2017. Univariate analyses were performed using the Fisher's exact test for categorical variables and the Wilcoxon rank sum test for continuous variables. Multivariable logistic regression was performed to identify factors independently associated with mortality.

RESULTS

We included 374 patients who underwent an emergent complex open AAA repair during the study period. There were 142 (38%) cases performed for rupture with hypotension, 141 (38%) for rupture without hypotension, 40 (11%) for symptomatic AAA, and 51 (14%) for another indication. The distribution by aneurysm type was 224 juxtarenal AAAs, 122 suprarenal AAAs, and 28 type IV TAAAs. Overall, there was a 30-day mortality of 32% (118 deaths). For those with juxtarenal AAA repair, 67 (30%) patients died within 30 days; there were 38 (31%) deaths within 30 days in those with suprarenal AAA, and 13 (46%) deaths within 30 days in those with type IV TAAA. On univariate analysis, preoperative variables associated with death were increasing age, use of a transperitoneal surgical approach, lower preoperative estimated glomerular filtration rate, low baseline albumin concentration (<3.5 g/dL), need for preoperative transfusion, low body mass index (<18.5 kg/m²), and hypotension at presentation. Intraoperative variables associated with mortality were supraceliac clamp location and concurrent renal revascularization. On multivariable analysis, factors independently associated with death included rupture with associated hypotension (reference: other emergent indication; adjusted odds ratio [AOR], 3.28; confidence interval [CI], 1.75-5.41; P < .001), age >60 years (reference: <60 years; AOR, 1.59; CI, 1.18-2.13; P = .002), longitudinal laparotomy incision (reference: retroperitoneal; AOR, 3.28; CI, 1.75-6.16; P < .001), and supraceliac cross-clamp (reference: clamp above one renal artery; AOR, 2.14; CI, 1.31-3.50; P = .003).

CONCLUSIONS

Nearly one-third of patients die within 30 days of emergent open complex AAA repair. Mortality is particularly high for patients with type IV TAAAs, approaching 50%. Predictors of 30-day mortality include rupture with associated hypotension, increasing age, supraceliac clamp location, and longitudinal transperitoneal repair approach. These results will help inform surgical decisions preoperatively and intraoperatively.

Superficial femoral artery access for endovascular aortic repair

OBJECTIVE

The majority of endovascular aneurysm repair procedures are performed through the common femoral artery (CFA). Arterial access is gained by surgical cutdown or percutaneous approach. The surgical approach has a relatively high local complication rate. We describe superficial femoral artery (SFA) access as an alternative to CFA exposure to minimize wound complications and to facilitate swift recovery.

METHODS

A single-center, retrospective study of patients undergoing endovascular aneurysm repair between 2014 and 2016 was performed; 195 patients undergoing 215 procedures were included, 114 with CFA cutdown, 87 with SFA cutdown, and 14 with combined SFA and CFA procedures. Epidemiologic parameters, risk factors, procedural details, operative and postoperative complications, and time to discharge were assessed. Independent samples two-sided t-test and χ² test were used to compare the SFA and CFA. A P value < .05 was considered statistically significant. A multivariate adjusted model confirmed the results. The proximal SFA is assessed by computed tomography angiography for patency and suitability. The minimal SFA diameter of 6 mm was determined for considering SFA access. Through a longitudinal incision at the upper thigh, the SFA is exposed and catheterized. Devices are inserted sheathless and replaced by small-diameter sheaths (14F-16F). Patients undergo peripheral vascular examination before and after the procedure.

RESULTS

Age, sex, and risk factor distribution were similar in both groups. Aneurysm size and device diameters were also similar. There were 12.1% of cases that were not suitable for the SFA approach. Access-related bleeding (0.7% SFA, 7% CFA; P = .004), ischemia (0.7% SFA, 7.6% CFA; P = .002), and venous injury (0% SFA, 1.3% CFA; P = .102) were minimized with SFA exposure. This led to almost 50% decrease in patients requiring additional arterial reconstruction during the procedure (6.5% SFA, 12.8% CFA; P = .059). SFA cutdown was also associated with lower wound complication rate (infection, seroma, and hematoma; 13.2% SFA, 34.9% CFA; P = .000). Neuropathy (mostly sensory) was higher with SFA exposure (13.8% SFA, 5.2% CFA; P = .008). The patients' recovery was faster in the SFA group, resulting in 14.3% reduction of hospital stay after the procedure (P = .005). Secondary access-related procedures were also lower in the SFA group (2.2% SFA, 8.7% CFA; P = .045).

CONCLUSIONS

The SFA approach is easier to perform and has a lower complication rate compared with the CFA approach. During the procedure, there is no dissection or damage to arterial branches, especially to the deep femoral artery. The SFA approach has a low complication rate and can be an alternative to percutaneous access when it is unsuitable.

Evolving Management of Distal Anastomotic Technical Issues During Open Aortic Aneurysm Repair

BACKGROUND

Thrombosis of the iliac anastomosis is an important complication of open aortic aneurysm repair. We evaluated our evolving management of this complication to an endovascular approach and compared it with open revision to the common femoral artery.

METHODS

Consecutive patients undergoing open aortic aneurysm repair from January 2009 through November 2016 at our institution were reviewed. Patients who developed iliac limb flow issues or thrombosis intraoperatively or within 48 hrs postoperatively were identified. Patients were grouped by management strategies of either 1) an endovascular approach including iliac angiography, thrombectomy if needed, and stenting or 2) open surgical revision of the iliac anastomosis with or without bypass to the common femoral artery. Demographics, comorbidities, operative variables, and outcomes were retrospectively analyzed between groups. Primary patency and mortality were assessed by Kaplan-Meier estimates.

RESULTS

There were 711 patients who underwent aortoiliac aneurysm repair during the study period. 43/711 patients (6.0%) developed early perioperative iliac limb flow issues including thrombosis. Twenty-nine patients (31 limbs) were managed by an endovascular approach, and 14 patients (15 limbs) were managed by open surgical revision. The mean age of the cohort was 69 years, and 27 patients (62.8%) were male. Preoperative creatinine and diabetes frequency were higher in patients managed by an endovascular approach, although no other differences existed between preoperative comorbidities. Thrombosis or limb flow issues presented intraoperatively more commonly in the open surgical group and in the first 24 hrs postoperatively in the endovascular group. All patients had complete restoration of outflow as a result of the rescue procedure. Transfusion requirements and crystalloid replacement were significantly higher in the open surgical group. Length of stay, perioperative complications, and mortality were similar between groups. Overall, 21/31 limbs in the endovascular group and 9/15 limbs in the open surgical group had postoperative imaging, with mean follow-up of 35.0 and 55.6 months, respectively. Only one patient in the cohort lost patency: an iliofemoral jump graft that presented with late infection after postoperative wound infection, requiring staged extra-anatomic bypass and explant at 12 months. Three-year primary patency was 100% for the endovascular group and 85.7% for the surgical group by Kaplan-Meier method (P = 0.32). Endovascular management became our institution's primary salvage approach during the study. Whereas 8/15 limbs (53.3%) were managed by an endovascular approach from 2009-2011, 23/31 (74%) were managed by iliac stenting from 2012-2016.

CONCLUSIONS

Endovascular management of iliac limb flow issues or thrombosis after open aneurysm repair is potentially a viable alternative to open surgical revision in the early postoperative period.

A new approach for the pre-clinical optimization of a spatial configuration of bifurcated endovascular prosthesis placed in abdominal aortic aneurysms

Complexity of the spatial configuration of an aortic implant with bifurcation in the distal part is related to changes in blood hemodynamic in the area of bifurcation which may disturb blood flow and lead to thrombus formation. This study was designed to characterize parameters which define spatial configuration of an aortic implant for which the risk of thrombus formation is the smallest. We used AngioCT data from 74 patients, aged 55 ±10 years, after endovascular procedure to prepare 3D geometries of stent-grafts. Computational Fluid Dynamics (CFD) simulations were used to reconstruct blood hemodynamic and simulate thrombus formation. Next, geometric parameters of stent-grafts included the ratio of volume of upper part to the bifurcations, the relation of inlet and outlet diameters of a stent-graft and deformations in the iliac part of the stent-graft were analyzed. We also analyzed tortuosities (spiral twisting of the flow around the flow direction) and bends (the largest angulation in distal part of a stent-graft). The CFD results were confronted with AngioCT data to verify if computer generated thrombus appeared in particular patient. Additionally, geometric parameters of analyzed stent-grafts were used to propose a mathematical tool for prediction of thrombus appearance. The results showed that tortuosities and bends of a stent-graft had the highest impact on thrombus formation. Formation of thrombi was observed in 22% to 31% of cases (at blood hematocrit Hct = 40%) even for small values of tortuosities and bends indicating that these parameters are dominant in determining blood clotting. Our calculated results overlapped with clinical data in 80% to 91%. Therefore, we conclude that tortuosities and bends have high impact on thrombus formation and should be under special attention during stent-graft recommendation and patients’ follow-ups.