Factors for Sac Size Change of Abdominal Aortic Aneurysm after Endovascular Repair

Remodeling of abdominal Aortic Aneurysm Sac following EndoVascular Aortic Repair: Association with Clinical, Surgical, and Genetic factors

After successful EndoVascular Aortic Repair (EVAR), abdominal aortic aneurysms (AAA) sac will undergo negative remodeling (i.e. shrinkage) as a measure of successful exclusion. Determinants of shrinkage after EVAR are not fully known. In 84 post-EVAR patients, time course of AAA diameter after repair and occurrence of endoleaks (ELs) have been correlated with clinical history, medications, anthropometric data, vascular anatomy, and matrix metalloprotease (MMP) genetic variants (namely MMP-1 rs1799750, MMP-3 rs35068180, MMP-9 rs2234681, rs917576, rs917577, MMP-12 rs652438, and TIMP1 rs4898). During follow-up, 41 ELs were detected in 37 patients (44%, 10.4 events/100 pt./y), accounting for AAA dilation or reduced shrinkage (P<0.001). High-flow ELs (type 1 and/or 3) occurrence was associated with warfarin use, MMP9 rs17577 polymorphism, and unfavorable anatomy, while low-flow type 2 ELs occurred more often in TIMP1 rs4898 non-T carriers. In EL-free patients, AAA diameter decreased for the first three years, (-4, -3 and - 2 mm/year respectively) and remained stable thereafter. Shrinkage between two measurements (n= 120) was associated with smaller AAA diameter at the baseline, peripheral arterial disease (PAD), patients' older age at intervention, and G-/G- genotype in MMP1 rs1799750 (binary logistic regression, P=0.0001). Aneurysmal sac shrinking occurs for few years after EVAR, only in patients without EL, and is related to older age, PAD, smaller aneurysm size and putative lower MMP1 expression while EL occurrence prevents such a remodeling and is mainly related to local-acting factors like unfavorable anatomy, anticoagulation, and MMP9 and TIMP1 genetic polymorphisms.

A Five-Year Computed Tomography Follow-up Study of Proximal Aortic Neck Dilatation After Endovascular Aortic Repair Using Four Contemporary Types of Endograft

OBJECTIVE

This study analysed the progression of proximal aortic neck diameter in patients with asymptomatic abdominal aortic aneurysms, treated by endovascular aortic repair using four different, contemporary types of endograft.

METHODS

This is a retrospective study of four cohorts of 30 patients presenting with asymptomatic abdominal aortic aneurysms and treated with endovascular aortic repair using four different types of contemporary endografts, namely Endurant® (Medtronic), Excluder® (W.L. Gore), Zenith® (Cook Medical) and Ovation® (Endologix) endografts. Patients' demographics and aortic aneurysm measurements, including suprarenal aortic, proximal infrarenal neck and maximum aortic aneurysmal diameter, were gathered from the patients' electronic medical records, pre- and post-interventional computed tomography studies, respectively. Diameter measurements were modelled as a function of endograft type; an interaction test was used to test whether the evolutions over time were different between the four types of endograft.

RESULTS

Suprarenal aortic diameter increased over time (P = 0.0235) and maximum aortic aneurysm diameter decreased over time (P = 0.0008) in the four types of endograft. The progressive increase in proximal neck diameter from preoperative baseline up to five years of follow-up was 1.20 mm for Endurant (P = 0.0054), 1.72 mm for Ovation (P = 0.0006), 1.14 mm for Excluder (P = 0.0102) and 2.83 mm for Zenith (P < 0.0001), respectively. Five patients (4%) presented with a late-type 1a endoleak: Endurant (n = 1); Ovation (n = 2) and Zenith (n = 2).

CONCLUSION

All endografts were associated with a progressive dilatation of the proximal aortic neck over a time interval of five years and may be associated with late-type 1a endoleak.

The Effect of Transfusion of Two Units of Fresh Frozen Plasma on the Perioperative Fibrinogen Levels and the Outcome of Patients Undergoing Elective Endovascular Repair for Abdominal Aortic Aneurysm

BACKGROUND

We aimed to investigate whether the transfusion of 2 units of fresh frozen plasma (FFP) immediately post aneurysm exclusion has any effect on the perioperative fibrinogen levels and the outcome of patients undergoing elective endovascular repair (EVAR) of abdominal aortic aneurysm (AAA).

METHODS

Consecutive infrarenal AAA patients undergoing elective EVAR with the bifurcated Endurant-II stent-graft (Medtronic) were recruited from 2 vascular units. The first unit has a routine policy of administering 2 units of FFP immediately upon aneurysm exclusion (FFP group), whereas the second unit has no such policy (control group). Serum fibrinogen levels were measured on admission and 24 hr post-EVAR and the perioperative change in fibrinogen (Δfib) was calculated (24-hr postoperative minus preoperative fibrinogen). The 2 groups were compared with regards to the perioperative fibrinogen levels (preoperative, 24-hr postoperative, and Δfib) and the outcome (endoleaks, reinterventions, major adverse cardiovascular events, death) during follow up.

RESULTS

A total of 70 patients (41 in the FFP group, 29 controls) were examined. There were 68 men, the mean age was 70 ± 7 years and the maximum AAA diameter was 63.3 ± 13.8 mm. During the follow up (34 ± 19 months), a total of 6 endoleaks were recorded (2 type Ia, 2 type Ib and 1 type II). Mean preoperative fibrinogen, 24-hr postoperative fibrinogen and Δfib was 391.1 ± 92.8 mg/dL, 367.7 ± 97.8 mg/dL and -23.5 ± 51.02 mg/dL, respectively. There was a trend for the fibrinogen to fall 24 hr postprocedure, but this was not statistically significant (P = 0.07). There was a weak negative association between Δfib and endoleaks (P = 0.007, r = -0.29). Compared to controls, the FFP group had a higher 24-hr postoperative fibrinogen (401.8 ± 112.9 mg/dL vs. 319.3 ± 34.9 mg/dL, P < 0.0001) and a lower Δfib (-3.00 ± 56.01 mg/dL vs. -52.48 ± 21.15 mg/dL, P < 0.0001). No significant difference was observed between the 2 groups with regards to endoleaks, reinterventions, major adverse cardiovascular events, or deaths.

CONCLUSIONS

Transfusion of 2 units of FFP postaneurysm exclusion prevents a significant drop in plasma fibrinogen 24 hr post-EVAR, but the impact on clinical outcome has yet to be defined.

Decreased Abdominal Aortic Aneurysm Size Following EVAR in Patients With CT Evidence of Subclinical Thoracic Aortic Dissection

BACKGROUND

Aneurysm sac regression following endovascular repair (EVAR) of an abdominal aortic aneurysm (AAA) is an established indicator of surgical success. However, even with a completely excluded aneurysm, the degree of aortic sac regression may vary. This study evaluates the relationship between aneurysm sac regression after EVAR and the presence of morphological features in the thoracic aorta that can be associated with a subclinical aortic dissection, termed dissection morphology in this study.

METHODS

Patients who underwent EVAR to repair an infrarenal aortic aneurysm at Mount Sinai Hospital between 1996 and 2017 with a postoperative CT scan and a 3-year follow-up scan available for analysis were included in the study. Patients with a type I or type III endoleak were not included. The thoracic aorta was evaluated for dissection morphology on CT scan, which included the presence of aortic dissection, penetrating aortic ulcers, and intramural hematomas. AAA sac regression after EVAR was compared between patients with dissection morphology (n = 157) and patients without those characteristics (n = 141). An independent investigator performed the CT analysis and was blinded to the degree of sac regression.

RESULTS

Demographics and comorbid clinical conditions were compared between patients with and without dissection morphology. There were no significant differences in age, gender, smoking habits, or cardiovascular conditions. The median AAA diameter after EVAR, over the course of the study, in patients with dissection morphology decreased by 11.30 mm (-17.20, -3.60) compared to a median change of 0.30 mm (-8.60, 8.60) in patients without dissection morphology features (p < 0.001). Patients with dissection morphology also had fewer type II endoleaks in postoperative follow-up scans (22.9% vs. 53.9%, p < 0.001). Additionally, patients with dissection morphology had longer EVAR operative times (192.00 min [167.25, 230.00] vs.174.00 min [150.00, 215.00], p = 0.004). AAA-related mortality after 3 years was not significantly different between the 2 groups (p = 1.0).

CONCLUSIONS

The presence of imaging features consistent with dissection morphology in the thoracic aorta correlated with greater AAA sac regression and fewer type II endoleaks after EVAR. Assessing these imaging features in patients undergoing EVAR may be useful in understanding aneurysm behavior in terms of aneurysm growth, risk of rupture, and outcomes following endovascular surgery. Identifying differential rates of aneurysm sac regression may have implications regarding the role of subclinical dissections in the etiology of AAA development.

Higher preprocedural fibrinogen levels are associated with aneurysm sac regression after EVAR

Summary. Background: The aim of our study was to determine the diameter of the aneurysm sac 24 months after endovascular abdominal aortic aneurysm repair (EVAR); to identify factors associated with sac regression, and to determine the impact of sac regression on all-cause mortality during long-term follow-up. Patients and methods: We conducted a retrospective review of prospectively collected data from patients treated with EVAR between January, 2010 and July, 2016. Sac regression was defined as at least 5 mm decrease in aneurysm diameter in relation to the preprocedural diameter seen on computed tomography angiography. Sociodemographic information, comorbidities, treatment, laboratory parameters, selected anatomical and genetic factors were all analysed to determine their impact on sac regression. Results: During the study period, 124 patients with mean age of 71.2 ± 7.2 years met the inclusion criteria. Sac regression was found in 45.2% of patients. Higher preprocedural fibrinogen was found in patients with sac regression in comparison with patients with stable sac or sac expansion (3.84 g/l vs 3.47 g/l; p = 0.028). In multivariate analysis after adjustment for age, hypertension, sex, smoking, dyslipidaemia, volume and percentage of intraluminal thrombus higher fibrinogen was associated with an increased probability of sac regression (OR 2.47; 95% CI 1.29–4.72; p = 0.006). Persistent type II endoleak was associated with significantly lower probability of sac regression in univariate and multivariate analysis after adjustment for age, hypertension, sex, smoking and dyslipidaemia (OR 0.26; 95% CI 0.10–0.66; p = 0.004). Higher age was a significant predictor of sac regression in multivariate analysis after adjustment for hypertension, sex, smoking and dyslipidaemia (OR 1.07; 95% CI 1.02–1.14; p = 0.012). No difference was found between patient subgroups with and without sac regression in all-cause mortality during follow-up. Conclusions: Higher preprocedural fibrinogen, absence of persistent type II endoleak and higher age were predictive factors of aneurysm sac regression post-EVAR.

Perioperative factors associated with aneurysm sac size changes after endovascular aneurysm repair

PURPOSE

To identify the perioperative factors associated with aneurysm size changes after endovascular aortic aneurysm repair (EVAR).

METHODS

Between August, 2008 and December, 2014, 187 patients underwent EVAR treatment in our institution. The subjects of this study were 135 of these patients without peripheral artery disease, who were followed up with computed tomography (CT) for 3 years. Significant aneurysm size change was defined as sac size change of more than 5 mm from the baseline.

RESULTS

Sac enlargement was identified in 25 patients (18.5%) and sac shrinkage was identified in 59 (43.7%) patients. The factors associated with sac enlargement were postoperative pulse wave velocity (OR: odds ratio 3.80, p = 0.047), prevalence of a type 2 endoleak 1 week after surgery (OR 4.26, p = 0.022), inner diameter (OR 1.10, p = 0.005), and distance from the lower renal artery to the terminal aorta (OR 1.05, p = 0.017). The factors associated with sac shrinkage were prevalence of a type 2 endoleak (OR 0.09, p < 0.001) and preoperative pulse wave velocity (OR 0.32, p = 0.022). The factors independently associated with type 2 endoleak were the use of an Excluder device (OR 3.99, p = 0.002) and the length of the aneurysm (OR 1.02, p = 0.027).

CONCLUSION

Inner diameter, treatment length, perioperative pulse wave velocity, and type 2 endoleak were associated with sac size changes after EVAR.