Influencing factors of sac shrinkage after endovascular aneurysm repair

ObjectiveSac shrinkage is considered a reliable surrogate marker of success after endovascular aneurysm repair (EVAR). Whereas sac shrinkage is the best expected outcome, predictive factors of sac shrinkage remain unclear. The aim of this study was to identify the role of preoperative and postoperative influencing factors of sac reduction after EVAR.MethodsOnline searches across MEDLINE, Embase, and Cochrane Library medical databases were simultaneously performed. Study effects were pooled using a random-effects model, and forest plots were generated for every potential influencing factor.ResultsA total of 24 studies with 14,754 patients were included (mean age, 73.4 years; 76% male). At a mean follow-up of 24 months, the pooled shrinkage proportion was 47%. Random-effects meta-analysis revealed that renal impairment (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.57-0.96), type I endoleaks (OR, 0.17; 95% CI, 0.08-0.39), type II endoleaks (OR, 0.21; 95% CI, 0.14-0.33), and combined type I and type II endoleaks (OR, 0.32; 95% CI, 0.22-0.47) were found to prevent sac shrinkage, whereas hypercholesterolemia (OR, 1.24; 95% CI, 1.02-1.51) and smoking (OR, 1.32; 95% CI, 1.17-1.49) have a significant positive impact on sac shrinkage. In addition, there was a trend toward the association between shrinkage and statin therapy (OR, 4.07; 95% CI, 1.02-16.32) and nearly significant negative impacts of coronary artery disease (OR, 0.84; 95% CI, 0.70-1.01), diabetes (OR, 0.79; 95% CI, 0.60-1.04), and sac thrombus (OR, 0.88; 95% CI, 0.77-1.01) on sac shrinkage.ConclusionsIn this large meta-analysis of patients undergoing EVAR, we found that several comorbidity and postoperative factors were associated with postoperative sac shrinkage. These findings may contribute to a better understanding of the shrinkage process of patients undergoing EVAR.     

Abdominal aortic aneurysm sac shrinkage after endovascular aneurysm repair: correlation with chronic sac pressure measurement

OBJECTIVES: Abdominal aortic aneurysm (AAA) sac shrinkage after endovascular aneurysm repair (EVAR) is considered to be evidence of clinical success. Exclusion of the sac from systemic pressure is the likely cause of shrinkage. We report our continuing clinical experience with the use of a permanently implantable, ultrasound-activated remote pressure transducer to measure intrasac pressure and its correlation with changes in sac diameter over time. METHODS: Over a 22-month period, 21 patients underwent EVAR of an infrarenal AAA with implantation of an ultrasound-activated remote pressure transducer fixed to the outside of the stent-graft and exposed to the excluded aortic sac. Intrasac pressures were measured directly with an intravascular catheter and by the remote sensor at the time of stent-graft deployment. Follow-up sac pressures were measured by remote sensor and compared with systemic arterial pressure at every follow-up visit. Mean follow-up was 11.4 +/- 5.0 months (range, 1 to 26 months). Twenty patients had follow-up of > or =6 months. Mean pressure index (MPI) was calculated as the ratio of mean sac pressure to mean systemic pressure. RESULTS: Pressures could be obtained at all visits in 15 of the 21 patients. Fourteen of these 15 patients had follow-up of at least 6 months. Aneurysm sac shrinkage of >5 mm was seen in seven (50%) of these 14 patients. No aneurysm enlargement was observed in any patient. The MPI was significantly lower in patients with sac shrinkage at 6 months and at final follow-up. CONCLUSIONS: Endovascular aneurysm repair results in marked reduction of sac pressure in most patients. Patients with aneurysm shrinkage after EVAR have significantly lower MPI; however, the absence of sac shrinkage does not imply persistent pressurization of the sac. Further clinical follow-up will delineate the role of long-term sac pressure monitoring in surveillance after EVAR.     

Simple renal cyst and its association with sac shrinkage after endovascular aneurysm repair for abdominal aortic aneurysms

ObjectivePatients with abdominal aortic aneurysm (AAA) frequently have simple renal cyst (SRC), a common manifestation of connective tissue degeneration. This study aimed to determine whether SRC is a risk factor for failure of sac shrinkage after endovascular aneurysm repair (EVAR).MethodsBetween October 2013 and May 2017, there were 155 consecutive patients with an infrarenal AAA or a common iliac artery aneurysm who underwent EVAR with the GORE C3 Excluder (W. L. Gore & Associates, Flagstaff, Ariz) at Tokyo Medical University Hospital. All these patients were registered in a prospectively maintained database. Any kidney lesion >5 mm in diameter, with no evidence of contrast enhancement or septation and with low attenuation, was defined as SRC. A change in sac size of >5 mm from baseline was considered significant. The patients were divided into those with SRC and those without SRC, and sac shrinkage at 1 year and 2 years was compared. The presence of SRC was assessed with respect to being a risk factor for failure of sac shrinkage at 1 year using univariate and multivariable logistic regression analysis.ResultsThe patients were divided into two groups: those with SRC (92 patients [59.0%]) and those without SRC (63 patients [41.0%]). At 1 year and 2 years, significant differences were observed in the proportion of sac shrinkage between patients with SRC and those without SRC (19.2% vs 42.4% [P = .003] and 19.6% vs 53.3% [P = .001], respectively). Patients with SRC showed significantly less sac shrinkage than those without SRC at 1 year and 2 years (−2.0 ± 5.5 mm vs −4.4 ± 6.2 mm [P = .002] and −1.8 ± 6.3 mm vs −6.4 ± 8.6 mm [P = .005], respectively). Multivariable analysis demonstrated that SRC (odds ratio, 0.28; 95% confidence interval, 0.12-0.63; P = .002) and initial sac size (odds ratio, 1.05; 95% confidence interval, 1.01-1.09; P = .027) were positive and negative risk factors for sac shrinkage, respectively.ConclusionsThe presence of SRC is a risk factor for failure of sac shrinkage after EVAR. This suggests that AAA in patients with SRC has a more degenerated wall than in those without SRC. The property of the aneurysm wall may be associated with sac shrinkage after EVAR.     

Early sac shrinkage is a good surrogate marker of durable success after endovascular aneurysm repair in Japanese patients

ObjectiveThe applicability of early sac shrinkage as a predictor of a low risk of late complications after endovascular aneurysm repair (EVAR) in Asian populations has not been validated. This study aimed to analyze early sac shrinkage and its relationship with late complications in Asian people using a Japanese multicenter database. We also assessed the impact of endoleaks.MethodsA retrospective analysis of 697 patients who had undergone EVAR of abdominal aortic aneurysms from 2008 to 2015 and were followed up for at least 1 year was conducted. Late complications were defined as any aneurysm-related events occurring >1 year after EVAR, including >5-mm aneurysm sac enlargements and any reinterventions performed. Endoleaks without any evidence of sac enlargement or a requirement for additional treatment were not considered late complications.ResultsEarly sac shrinkage, defined as a >5-mm-diameter decrease within 1 year of EVAR, occurred in 335 patients (48.1%); type I endoleaks (T1ELs) and isolated type II endoleaks (iT2ELs; type II endoleaks without evidence of other endoleaks) were observed in 4.0% and 29.4%, respectively. During the mean follow-up period of 45.5 months, 93 late complications (13.3%) occurred. Kaplan-Meier curve and log-rank analyses showed that early sac shrinkage was a significant predictor for a lower risk of late complications (P < .001). Multivariate analysis revealed that early sac shrinkage was independently associated with a lower risk of late complications (adjusted hazard ratio, 0.425; P = .004). Conversely, T1ELs and iT2ELs were positively associated with late complication (adjusted hazard ratio, 11.774 and 5.137, respectively; both P < .001). Subsequent multivariate analysis demonstrated that T1ELs and iT2ELs were negatively associated with early sac shrinkage (adjusted odds ratio, 0.102 and 0.285, respectively; both P < .001).ConclusionsEarly sac shrinkage was associated with a low risk of late complications in Asian people and may be a good surrogate marker of durable success after EVAR. T1ELs and iT2ELs were negatively associated with early sac shrinkage and positively associated with late complications. Along with the high incidence of iT2ELs observed, T2ELs may be an important condition to consider after EVAR in the Asian population.     

Endoleaks after endovascular aneurysm repair lead to nonuniform intra-aneurysm sac pressure

OBJECTIVE: This was a study of intra-aneurysm sac pressures in patients who presented with endoleaks after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA). METHODS: Twenty-five patients (18 men, 7 women) with endoleaks, age (IQR 68 to 80), underwent 31 direct intra-aneurysm sac pressure measurements, DISP at 16 months after EVAR (IQR, 14 to 26 months). Diameter of AAA was 59 mm (IQR, 52 to 67 mm). Six patients underwent DISP twice. Tip-pressure sensors were used through direct translumbar puncture of the AAA except in three patients (transabdominal puncture in 2; endoluminal in 1). Mean pressure index (MPI) was calculated between simultaneously registered intra-aneurysm sac and systemic pressures. Values presented are medians with interquartile range (IQR). RESULTS: Type I endoleaks (n = 1) showed MPI of 93% in the nidus and 62% in the thrombus. Type II endoleaks were associated with lower MPIs in the thrombus (35%; IQR 24% to 38%) when AAAs shrank (n = 4) compared with when the AAAs remained unchanged (n = 11; MPI, 78%; IQR, 47% to 85%) or expanded (n = 6; MPI, 74%; IQR, 58% to 87%; P = .019). The nidus of type II endoleaks (MPI, 79%; IQR, 70% to 90%) had higher pressure than the thrombus (45%, IQR, 34% to 85%; P = .047; n = 7). Successful embolization of type II endoleaks led to AAA shrinkage (n = 3; MPI reduction, 13% to 31%) or diameter stability (n = 3; unchanged MPIs, 37% to 44%). Type III endoleaks (n = 3) had MPIs in the thrombus of 33% to 70%. CONCLUSIONS: Endoleaks after EVAR pressurize the AAA sac nonuniformly, with higher, near-systemic, pressure in the endoleak nidus compared with the thrombus. Nevertheless, type II endoleaks in shrinking AAAs have lower intra-sac pressure than expanding or stable aneurysms, and successful endoleak embolization reduces pressure.     

Device-specific aneurysm sac morphology after endovascular aneurysm repair: evaluation of contemporary graft materials

OBJECTIVE: This study analyzed device-specific aneurysm sac morphology after endovascular aneurysm repair (EVAR) with low-permeability devices. METHODS: Between September 2004 and May 2006, 122 patients were treated with EVAR. Three different devices were implanted: 47 Zenith (Cook, Indianapolis, Ind), 46 AneuRx (Medtronic, Santa Rosa, Calif) with Resilient Dacron Graft Material, and 29 Excluder (W. L. Gore & Associates, Flagstaff, Ariz) with low-porosity polytetrafluoroethylene (PTFE). Patients were followed up at 1, 6, and 12 months and then biannually with computed tomography (CT) angiography. Standard axial two-dimensional CT measurements were obtained and compared with preoperative imaging. The preoperative scan served as a baseline, and the minor axis diameter, measured at the largest axial cut of the abdominal aortic aneurysm, was compared with the same measurement at follow-up. RESULTS: Patient age, sex, and preoperative aneurysm morphology were similar among groups. Patients receiving the Zenith endograft had a significantly larger neck diameter; however, there was no difference in the neck length between groups. The rate of type II endoleaks was similar for the Zenith (17%), AneuRx (17%), and Excluder (14%). At 1, 6, 12, and 18 months, all three grafts were associated with sac shrinkage. The resulting decreases in mean aneurysm size at 18 months and corresponding shrinkage were Zenith, 11%, 6.4 +/- 1.8 mm; AneuRx, 18.9%, 12.7 +/- 2.7 mm; and the Excluder, 5.5%, 3.3 +/- 0.9 (P < .05). The sac size in the 19 patients with a type II endoleak decreased 8.06% compared with a 15.43% decrease in sac size in patients without endoleak at 6 months. No significant sac expansion > or =5 mm has been observed among any of the groups to date. CONCLUSIONS: Sac regression with all devices appears to have been favorably influenced by the new generation of graft materials and is improved compared with published reports of older generation graft materials for the AneuRx and Excluder. However, there is a trend toward greater sac regression with devices using Dacron vs PTFE. The relationship of aneurysm morphology and long-term effects on aortic stent grafts is yet to be determined.     

Aneurysm sac failure to regress after endovascular aneurysm repair is associated with lower long-term survival

Background

The early survival advantage of endovascular aneurysm repair (EVAR) compared with open repair reverses over time, possibly because of higher rates of reintervention related to endoleaks and aneurysm sac expansion. Therefore, we sought to examine the association between sac behavior, endoleaks, reintervention, and long-term survival.

One-year sac regression is associated with freedom from fatal adverse events after endovascular aneurysm repair

ObjectiveAlthough the predictors of long-term prognosis after endovascular aneurysm repair (EVAR) have been investigated, several reports have suggested that early sac shrinkage (ESS) is associated with superior long-term prognosis. However, it was not clear whether ESS was associated with aneurysm-related mortality. The aim of this study was to define fatal adverse events and to examine their association with ESS.MethodsAll consecutive patients who underwent EVAR for an abdominal aortic aneurysm at Nagoya University Hospital between June 2007 and August 2018 were identified. We defined ESS as an aneurysm diameter decrease of 10 mm or more at 1 year after EVAR, and we defined fatal adverse events as aneurysm-related death, aneurysm sac rupture, open conversion, secondary type Ia endoleak, or secondary type IIIa/b endoleak. Then, we evaluated the association between ESS and fatal adverse events and identified predictors of ESS.ResultsDuring the study period, 553 patients were identified and included. Fatal adverse events occurred in 42 patients (7.6%), and the details of the fatal adverse events were as follows: 13 aneurysm-related deaths, 17 aneurysm sac ruptures, 14 open conversions, 13 type Ia endoleaks, and 6 type III endoleaks. ESS occurred in 146 patients (26.4%). Kaplan-Meier curves showed that the ESS group had a significantly lower incidence of fatal adverse events (P < .001). Multivariate analysis showed that there were significant differences in terms of 5 or more preoperatively patent lumbar arteries (odds ratio [OR], 0.67; P = .049; 95% confidence interval [CI], 0.45-1.00), chronic kidney disease (OR, 0.49; P < .01; 95% CI, 0.29-0.84), and Zenith endograft use (OR, 1.76; P < .01; 95% CI, 1.16-2.67). Furthermore, the percentage of cases that achieved an aneurysm diameter of less than 40 mm was significantly higher in the ESS group (76.0% vs 15.5%; P < .01). The use of Zenith endografts showed a significantly higher rate of aneurysm disappearance than the use of Endurant endografts (P < .01) and Excluder endografts (P < .01). In addition, it was found that ESS was more likely to occur with the use of Zenith endografts, even when propensity score matching was performed for the neck morphology.ConclusionsESS was associated with a lower rate of life-threatening adverse events after EVAR. The use of Zenith endografts was a predictor of ESS and was associated with increased rates of long-term sac shrinkage and aneurysm disappearance compared with the Endurant and Excluder endografts. Using the predictors of ESS identified in this study, we may be able to expand the indications for EVAR to patients with a longer life expectancy.