Impact of Smoking on Endovascular Abdominal Aortic Aneurysm Surgery Outcome

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.

Biomechanics and Early Sac Regression after Endovascular Aneurysm Repair of Abdominal Aortic Aneurysm

Background

Sac regression after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAA) is regarded as a marker of successful response to treatment. Several factors influence sac behavior after EVAR, yet little is known about the value of preoperative biomechanics. The aim of this study was to investigate the difference in aortic biomechanics between patients with and without sac regression.

Methods

Patients treated with standard EVAR for infrarenal AAA at the Karolinska University Hospital between 2009 and 2012 with one preoperative and a minimum of two postoperative computed tomography angiography (CTA) scans were considered for inclusion in this single-center retrospective cohort study. Biomechanical indices such as AAA wall stress and wall stress-strength ratio as well as intraluminal thrombus (ILT) thickness and stress were measured preoperatively in A4ClinicRE (VASCOPS GmbH). AAA diameter and volume were analyzed on preoperative, 30-day, and 1-year CTAs. Patients were dichotomized based on sac regression, defined as a ≥ 5 mm decrease in maximal AAA diameter between the first two postoperative CTA scans. Multivariable logistic regression was used for analysis of factors associated with early sac regression.

Results

Of the 101 patients treated during the inclusion period, 64 were included. Thirty-nine (61%) demonstrated sac regression and 25 (39%) had a stable sac or sac increase. The mean patients age (73 years vs 76 years), male sex (85% vs 96%), and median AAA diameter (58 mm vs 58.5 mm) did not differ between patients with and without sac regression. Although no difference in preoperative biomechanics was seen between the groups, multivariable logistic regression revealed that a larger AAA diameter (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.06-1.51; P = .009) and smoking (OR, 22.1; 95% CI, 2.78-174; P = .003) were positively associated with sac regression. In contrast, the lumen diameter (OR, 0.87; 95% CI, 0.77-0.98; P = .023), ILT thickness (OR, 0.85; 95% CI, 0.75-0.97; P = .013), aspirin or direct-acting oral anticoagulant use (OR, 0.11; 95% CI, 0.02-0.61; P = .012), and mean ILT stress (OR, 0.35; 95% CI, 0.14-0.87; P = .024) showed a negative association. Patients with sac regression had fewer reinterventions (log-rank P = .010) and lower mortality (log-rank P = .012) at the 5-year follow-up.

Conclusions

This study, characterizing preoperative biomechanics in patients with and without sac regression, demonstrated a negative association between mean ILT stress and ILT thickness with a change in sac diameter after EVAR. Given that the ILT is a highly dynamic entity, further studies focusing on the role of the thrombus are needed. Furthermore, patients presenting with early sac regression had improved outcomes after EVAR.

The Effect of Smoking Status on Perioperative Morbidity and Mortality after Open and Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVES

This study quantifies the extent to which active tobacco smoking is deleterious towards outcomes following open and endovascular AAA repair.

METHODS

Open and endovascular abdominal aortic aneurysm (AAA) repairs between January 2003 and June 2020 in the Vascular Quality Initiative (VQI) were queried. Rupture, symptomatic status, and lack of 90 day follow up were exclusions. Patients were then placed into one of six groups : open AAA with active smoking (n=3788); open AAA with prior smoking (n=4614); open AAA never smokers (817); endovascular AAA active smokers (n=14173); endovascular AAA former smokers (n=25,831); and, endovascular AAA never smokers (n=6064). Comparison of baseline characteristics, co-morbidities, and adverse outcomes across each of the 6 cohorts was performed with open AAA in active smokers serving as the reference. Sub-analysis investigating open AAA repair in active smokers relative to open AAA in patients confirmed in VQI to have quit smoking between 30 and 90 days before surgery was performed. Smoking cessation for a minimum of 30 days before surgery was required to fall into the former smoker category.

RESULTS

In comparing open AAA in active smokers to open AAA in former and never smokers, the active smokers experienced significantly higher rates of pneumonia (P<.001). Combined additive morbidity and mortality was highest (54%) in active smokers (P<.001 relative to all cohorts other than open AAA former smokers P=.21). Smoking status did not impact morbidity or mortality incidence across individuals undergoing EVAR. Binary logistic regression for all AAA patients (open and endovascular combined) revealed those with any history of smoking to be more likely to experience 90 day mortality (adjusted OR 2.5 (2.2-2.9), P<.001) relative to never-smokers. Active smokers were similarly more likely to experience 90 day mortality than prior/never smokers combined (OR 1.23 (1.07-1.38), P<.001). Mortality within 90 days was significantly more likely (P<.001) with aging, female gender, larger aneurysms, preoperative history of congestive heart failure, chronic obstructive pulmonary disease, chronic renal insufficiency, peripheral artery disease, body mass index under 20 and over 35 mg/kg². Diabetes and coronary artery disease were also associated with 90 day mortality (P= .045 and .049 respectively). Quitting smoking between 30 and 90 days before open repair reduced combined additive morbidity and mortality relative to active smokers (OR 1.34, P =.038).

CONCLUSIONS

Smoking cessation 30 days before open AAA repair reduces perioperative morbidity and mortality. Smoking status does not impact morbidity and mortality in patients undergoing endovascular AAA repair. When combining all patients (open and endovascular), higher rates of 90 day mortality are associated with any history of smoking, aging, female gender and advanced pre-existing co-morbidities on multivariable analysis.

Predictors of Aneurysm Sac Shrinkage Utilizing a Global Registry

BACKGROUND

Aneurysm sac remodeling is a complex multifactorial process with unknown factors influencing sac regression after endovascular aortic aneurysm repair (EVAR). We sought to identify factors associated with this process by analyzing data obtained from patients treated with the GORE EXCLUDER endovascular aneurysm repair (EVAR) endoprosthesis from December 2010 to October 2016 enrolled in the Global Registry for Endovascular Aortic Treatment (GREAT).

METHODS

All patients enrolled in GREAT with three years CT angiography (CTA) follow-up in each of the three successive years after EVAR were included. The percentage of sac size reduction toward device diameter was calculated and used as a surrogate for sac regression with the formula used being: sac size reduction = ((AAA baseline diameter - AAA diameter at follow-up)/(AAA baseline diameter - device diameter))∗100. The cohort was divided into two groups in accordance with the percentage of aneurysm sac reduction at three years; one with the top quartile of patients and the other with the lowest three quartiles. Demographic and procedural variables were analyzed using univariate and regression modeling to determine factors predictive of sac regression.

RESULTS

There were 3265 subjects enrolled with follow-up as of May 2018 of which 526 (16.2%) had three years of CTA surveillance. Overall aneurysm sac size decreased from a mean of 58.0 mm (Std Dev: 10.4, range: 34.2, 100.0) to a mean of 49.3 mm (Std Dev: 14.1, range: 0, 140) for a percentage reduction toward device diameter of a mean 28.2% (Std Dev: 39.0, range: -103.7, 183.9). On multivariate logistic regression model; two factors proved to be statistically significant contributors to a larger percentage reduction in aneurysm sac: a conical neck (odds ratio [OR] = 1.64, P-value = 0.023) and a larger proximal device diameter (OR = 1.09, P-value = 0.023). On the other hand, two factors were negative predictors of sac shrinkage, namely: old age (OR = 0.96, P-value = 0.002) and larger baseline aneurysm sac diameter (OR = 0.98, P-value = 0.028).

CONCLUSIONS

Aneurysms with conical necks and larger proximal device neck diameters have an increased percentage change in sac size over time after EVAR. Older age and larger initial diameters of aneurysms were negatively associated with percentage change in sac size as well as sac regression. Further study is needed to determine the clinical utility of these observations and applicability across multiple endoprosthesis platforms.

The effect of the duration of preoperative smoking cessation timing on outcomes after elective open abdominal aortic aneurysm repair and lower extremity bypass

OBJECTIVE

Smoking has been associated with poor postoperative outcomes across various surgical procedures. However, the effect of quitting smoking preoperatively for elective operations is unclear. Our goal was to assess the temporal effect of smoking cessation before elective lower extremity bypass (LEB) and open abdominal aortic aneurysm (AAA) repair on perioperative outcomes.

METHODS

The Vascular Quality Initiative was reviewed for all patients with a documented smoking history and who underwent an elective LEB or open AAA repair from 2010 to 2017. Patients were then categorized into three groups: long-term smoking cessation (LTSC; defined as quitting smoking ≥8 weeks before surgery), short-term smoking cessation (STSC; defined as quitting smoking < 8 weeks before surgery), and current smokers (CS). Patient and procedure details were recorded. Univariate and multivariate analysis for crude and propensity-matched data were used to compare outcomes among groups.

RESULTS

We identified 15,950 patients with a documented smoking history who underwent an elective LEB (43.3% LTSC, 2.2% STSC, 54.5% CS) and 5215 patients who underwent an elective open AAA repair (42.9% LTSC, 2.4% STSC, 54.7% CS). LTSC patients compared with STSC and CS, respectively, were more often obese, diabetic, on aspirin, on a statin, had coronary artery disease, and had congestive heart failure, but were less likely to have chronic obstructive pulmonary disease (all P < .05). Perioperative outcomes demonstrated significant differences comparing LTSC with STSC and CS for myocardial infarction (3.4% vs 1.4% vs 1.4%), dysrhythmia (4.2% vs 2.5% vs 2.7%), 30-day mortality (1.6% vs .3% vs .9%), in-hospital mortality (1.1% vs 0% vs 0.5%; all P < .001) and congestive heart failure (1.8% vs .8% vs 1.5%; P = .003). There was no difference in outcomes after analysis of propensity-matched data for LTSC or STSC on any postoperative outcomes for LEB. For open AAA repair, LTSC compared with CS patients, respectively, were older, more often male, obese, on a statin, diabetic, and less frequently had chronic obstructive pulmonary disease (P < .05 for all). Perioperative outcomes demonstrated differences in pulmonary complications when comparing LTSC with STSC and CS (9.5% vs 8.0% vs 12.5%; P = .002). Multivariate analysis demonstrated that LTSC patients compared with CS were less likely to experience pulmonary complications (odds ratio, 0.65; 95% confidence interval, 0.53-0.79; P < .001). Propensity-matched multivariate analysis confirmed that LTSC remained significantly less likely to encounter pulmonary complications (odds ratio, 0.49; 95% confidence interval, 0.33-0.74; P = .001).

CONCLUSIONS

In our propensity-matched, risk-adjusted cohort, LTSC and STSC were not associated with perioperative outcomes after elective LEB. LTSC was associated with a significantly decreased odds of pulmonary complications after elective open AAA repair. STSC was not associated with perioperative outcomes after elective open AAA repair. If time permits, a longer period of smoking cessation should be attempted before elective open AAA repair.

Effectiveness of Embolization of Inferior Mesenteric Artery to Prevent Type II Endoleak Following Endovascular Aneurysm Repair: A Review of the Literature

Type II endoleak is a common complication that develops after endovascular aneurysm repair. Patients with type II endoleak, which has persisted for 6 months, have a significantly higher rate of aneurysmal sac enlargement, reintervention, and rupture. To date, several studies have examined the effectiveness of preoperative embolization of branch vessels for the prevention of type II endoleak. Particularly, the embolization of the large inferior mesenteric artery (IMA) seems to be a precise, safe, and effective method. IMA is a significant risk factor for type II endoleak. However, there is currently no strong evidence to prove which patients would benefit from preventive IMA embolization. In addition, considering the incidence of type II endoleak and the adverse event rate, routine embolization seems to be unreliable and time-consuming. Moreover, previous reports of preoperative IMA embolization were retrospective. Thus, prospective and randomized studies are necessary so that the usefulness of IMA embolization can be proved and the potential benefits can be assessed. To establish preventive IMA embolization as one of the effective therapeutic strategies to prevent type II endoleak and to maximize its therapeutic effect, we should provide a wide range of therapeutic strategies to suit the state of the patient.

Predictive Factors for Type II Endoleaks after Treatment of Abdominal Aortic Aneurysm by Conventional Endovascular Aneurysm Repair

BACKGROUND

The aim of this study was to identify the predictive factors for the development of type II endoleaks (EL-II) after endovascular aneurysm repair (EVAR).

METHODS

We assessed the preoperative and postoperative computed tomography data of 308 patients who underwent EVAR between 2000 and 2012 and in 84 of whom primary or secondary EL-II occurred. The data analyzed were: demographics, number and diameter of lumbar arteries (LAs), inferior mesenteric artery (IMA), median sacral artery (MSA), accessory renal arteries (ARas), maximum diameter of infrarenal abdominal aortic aneurysm, diameter and length of proximal aortic neck. Statistical analysis was performed using Stata software (version 12). Categorical parameters were compared between groups using chi-squared or Fisher's exact tests as appropriate. Continuous variables were analyzed using Student's t-test or Mann-Whitney test as appropriate (normality studied by the Shapiro-Wilk and homoscedasticity verified using the Fisher-Snedecor test).

RESULTS

Of the 308 patients included (mean age, 73.8 ± 8.74 years), 284 (92%) were men, 61 (20%) were smokers, 113 (37%) had chronic obstructive pulmonary disease, 215 (70%) were taking antiplatelet. Respectively, 13, 51, 60, 103, 28, 40, 2, and 7 patients had 1, 2, 3, 4, 5, 6, 7, and 8 patent LAs. Before surgery, 221 IMAs and 136 MSA were patent. The sources of EL-II were: LA (n = 51), IMA (n = 22), MSA (n = 1), IMA and LA (n = 8), IMA and ARa (n = 1), and unknown (n = 1). Logistic regression models adjusting for clinically relevant covariables (age, American Society of Anesthesiologists, smoking status, dyslipidemia, and diuretics) were proposed to study morphologic EL-II predictive factors, first in the entire population, and then in the more specific population for whom IMA was patent. Risk factors of occurrence EL-II were: permeability of the IMA (70 patients [83%] vs. 155 [69%], P = 0.01), IMA diameter (3.49 mm vs. 2.71 mm, P < 0.001), number of LAs patent higher than or equal to 4 (P < 0.001), the mean LA diameter greater than 2.4 mm (P < 0.001), and MSA diameter (2.28 mm vs. 1.94 mm; P < 0.01).

CONCLUSIONS

Our results show the major role of the number and diameter of the patent aortic branches in the development of EL-II. As they can result in complications increasing the morbidity and mortality after EVAR, it is relevant to identify the risk factors of their occurrence.

The influence of smoking on endovascular abdominal aortic aneurysm repair

OBJECTIVE

The main purpose of this study was to evaluate the influence of smoking on perioperative outcomes of endovascular aneurysm repair (EVAR), aneurysm sac behavior, abdominal aortic aneurysm (AAA) neck growth after EVAR, and its effect on stent graft migration during follow-up.

METHODS

Baseline characteristics and follow-up data were collected prospectively by patient record forms. Follow-up visits were scheduled at 1, 3, 6, 12, 18, and 24 months, and annually thereafter and included a clinical examination and imaging studies. Patients were stratified in three groups according to their smoking status as nonsmokers, former smokers, and smokers.

RESULTS

This study analyzed the data for 4176 nonsmokers, 2406 former smokers, and 2056 smokers who were enrolled prospectively in the European Collaborators on Stent-Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) database. Compared with nonsmokers, smokers required more percutaneous transluminal angioplasty and stent placements during EVAR (P < .001), and stent graft migration occurred more often (hazard ratio, 1.45; 95% confidence interval, 1.03-2.05; P = .033). Nonsmokers had more late type II endoleaks than former smokers and smokers (58.5%, 55.9%, and 35.5%, respectively; P < .001). Smoking had no effect on aneurysm sac behavior or AAA neck growth after EVAR.

CONCLUSIONS

Smokers need more percutaneous transluminal angioplasty procedures and stents during EVAR. They have fewer late type II endoleaks during follow-up; however, smokers should be closely monitored because they have an increased risk of stent graft migration.

Smoking and Aortic Diseases

Cigarette smoking is a major vascular risk factor and in this context, it is an independent risk factor for the development of aortic disease, especially the formation and growth of abdominal aortic aneurysms (AAA). Medline was searched up to January 31, 2007 for the relevant literature for this review of the mechanisms by which smoking causes aortic wall damage and its subsequent impact on the clinical manifestation of this process. Idiopathic AAAs and aortic dissection are considered, as well as other aortic diseases (eg, Takayasu, Kawasaki, Behcet and Buerger). There is evidence suggesting an abnormal homeostasis between proteolytic and antiproteolytic activity in the vascular wall during the development of AAAs, and these mechanisms can be influenced by smoking. Smoking cessation plays an important role in the management of aortic disease.