Preoperative infra- and suprarenal aortic pulsatile distension is comparable between relatively young and older patients with an abdominal aortic aneurysm.

BACKGROUND: Young healthy individuals have a large aortic pulsatile distension during the cardiac cycle. In patients with an abdominal aortic aneurysm (AAA), aortic distension during the cardiac cycle is associated with stent graft migration. However, whether the pulsatile distension is larger in relatively young patients with an AAA compared to older AAA patients is unknown. This study investigated whether preoperative pulsatile aneurysm neck distension is related to age. METHODS: From our database of endovascular aneurysm repair (EVAR), we selected 25 consecutive male patients ≤65 years of age (group 1) and 25 consecutive patients >65 years of age (group 2). All patients had a preoperative electrocardiogram-triggered computed tomography angiography scan consisting of 8 phases. Aortic area and diameter changes per heartbeat were measured at 2 levels: (A) 3 cm above and (B) 1 cm below the most distal renal artery. RESULTS: In group 1 compared to group 2, distension during the cardiac cycle at level A was 1.6 ± 0.4 versus 1.5 ± 0.4 mm (P = 0.62), and the aortic area increase was 45.4 ± 19.6 versus 41.7 ± 20.8 mm(2) (P = 0.52). Aortic distension at level B was 1.4 ± 0.3 versus 1.5 ± 0.4 mm (P = 0.79), and the area increase was 35.5 ± 12.0 versus 35.0 ± 15.5 mm(2) (P = 0.90). CONCLUSIONS: Preoperative pulsatile aneurysm neck distension did not differ between younger and older patients; therefore, we do not expect young patients to have more pulsatile distension-related complications after EVAR.

Morphologic predictors of aortic dilatation in type B aortic dissection.

BACKGROUND: Conservative management of acute type B aortic dissection (ABAD) is often associated with aortic dilatation during follow-up increasing the risk of aortic rupture. The goal of this study was to investigate whether morphologic characteristics of the dissection can predict aortic growth. METHODS: All conservatively managed ABAD patients from four referral centers were included (2000 to 2010). Aortic diameters were measured at five levels at baseline and at the last follow-up computed tomography angiography, and annual aortic growth rates were calculated for all segments. Linear regression was used to study the influence of aortic morphologic characteristics for aortic dilatation. RESULTS: Included were 62 patients (41 men) with a mean age of 60.3 ± 10.7 years. Among the 310 analyzed aortic segments, 248 (80.0%) were dissected, of which 211 (85.1%) showed aortic growth. Overall, the mean diameter increased from 36.1 ± 9.4 to 40.2 ± 11.1 mm (P < .01), which corresponds with a mean aortic growth rate of 3.1 ± 6.3 mm/y. Multivariate linear regression analysis showed that male sex (95% confidence interval [CI], 0.60-4.04; P = .005) and a saccular false lumen (95% CI, 2.07-7.81: P = .001) were associated with a significantly increased aortic growth rate. Increasing age (95% CI, -0.23 to -0.04; P = .005), increased number of entry tears (95% CI, -2.40 to -0.43; P = .005), false lumen located on the aortic outer curvature (95% CI, -4.30 to -0.38; P = .019), and a circular configuration of the true lumen (95% CI, -5.35 to -0.32; P = .027) were associated with a decreased aortic growth rate. CONCLUSIONS: Multiple morphologic characteristics appear to predict aortic dilatation in ABAD patients treated medically. Early assessment of these morphologic signs may be useful in the selection of ABAD patients who might benefit from closer radiologic surveillance or prophylactic intervention.

The influence of neck thrombus on clinical outcome and aneurysm morphology after endovascular aneurysm repair.

OBJECTIVE: This study investigated the influence of significant aneurysm neck thrombus in clinical and morphologic outcomes after endovascular aneurysm repair (EVAR). METHODS: The patient population was derived from a prospective EVAR database from two university institutions in The Netherlands from 2004 to 2008. Patients with significant thrombus in the neck (>2 mm in thickness in at least >25% of circumference) were identified as the thrombus group and were compared with the remaining patients without neck thrombus (no-thrombus group), treated within the same period. The primary end point was clinical success. Secondary end points included technical success and rates of decline in renal function. Detailed morphologic analysis of the aortic neck was serially performed for the thrombus group patients to assess changes in thrombus volume. RESULTS: The study included 389 patients: 43 (39 men; mean age of 72.3 years) met the criteria for the thrombus group; of these, 31 (72%) had significant thrombus in >50% of the aortic neck circumference, and 8 (19%) had circumferential thrombus >2-mm thick. Median follow-up was 3.34 years (interquartile range, 2.67-4.72). The estimated 5-year clinical success rate was 74% for the thrombus group and 62% for the no-thrombus group (P = .23). Endograft migration was more frequent in the thrombus group (P = .02). Multivariable Cox regression analysis showed a significant association between migration and use of a device without active fixation (hazard ratio, 4.9; 95% confidence interval, 1.31-18.23; P = .018) but not with the presence of neck thrombus (P = .063). No differences were found in the rates of decline in estimated glomerular filtration rate at 30 days and during follow-up between the thrombus and no-thrombus groups. The thrombus volume in the first 10 mm of aortic neck was progressively reduced over time until it was not measurable in most patients, resulting in complete circular attachment of the endograft to the vessel wall. CONCLUSIONS: Our findings suggest that the presence of aneurysm neck thrombus has no significant influence on short-term and midterm EVAR results.

The chimney graft, a systematic review.

BACKGROUND: Approximately 20% to 30% of the patients are considered not eligible for standard endovascular aneurysm repair because of aortic neck morphology. Most of these patients have an aortic neck situated in the vicinity of the aortic side branches, requiring extensive open surgery. The introduction of fenestrated and branched stent grafts has made endovascular branch preservation possible, but these procedures are time-consuming and expensive. The chimney procedure offers a readily available endovascular alternative for the treatment in patients with acute aneurysms and challenging anatomy. We conducted a systematic review to evaluate the short- and long-term results of the chimney procedure. METHODS: A comprehensive literature search for studies describing the chimney procedure was performed using MEDLINE and Excerpta Medica Database. All articles were critically appraised and included, based on relevance, validity, and outcome measures. Patient characteristics, details of the surgical intervention, and short- and long-term outcomes were studied. RESULTS: A total of 75 patients were included who underwent a chimney procedure for the preservation of a total of 96 branches. Used operating techniques differed considerably between all studies, with an overall technical success rate of 98.9%. Three perioperative deaths were reported, of which one patient died from intervention-related complication. The follow-up duration ranged from 2 days to 54 months. Late complications included three deaths, none of which was device or aneurysm related. Three chimney grafts occluded during follow-up, of which two required reintervention. CONCLUSION: The chimney procedure appears as an acceptable alternative for patients in an emergency setting, although data regarding long-term follow-up are not yet available.

One-year multicenter results of 100 abdominal aortic aneurysm patients treated with the Endurant stent graft.

OBJECTIVE: The Endurant (Medtronic, Minneapolis, Minn) is a new stent graft specifically designed to make more patients anatomically eligible for endovascular aneurysm (EVAR). This study presents the 1-year results of 100 consecutive patients with abdominal aortic aneurysms (AAAs) treated with the Endurant stent graft in real-life practice. METHODS: All clinical preoperative, operative, postoperative, and 1-year follow-up data of patients with the Endurant stent graft from three tertiary centers were prospectively collected. Patients underwent computed tomographic angiography (CTA) preoperatively, at 1 month, and at 1-year post-EVAR. The first 100 patients with an implantation date at least 1 year before our date of analysis and complete information were included. Clinical data, AAA characteristics, presence of endoleaks, graft migration, and other EVAR-related complications were noted. All values are stated as mean ± SD (range). RESULTS: This study included 100 patients with AAAs (88 men) with a mean age of 73 ± 8 years (47 to 87 years), an AAA size of 61 ± 10 mm (31 to 93 mm), an AAA volume of 210 ± 122 mL (69 to 934 mL), a proximal neck length of 33 ± 14 mm (9 to 82 mm), and an infrarenal angulation of 44 ± 25° (0°-108°). Nineteen of the 100 included patients had at least one anatomic characteristic that was considered a violation of the instructions for use (IFU) of the Endurant stent graft. A primary technical success was achieved in 98% of the patients (one additional stent placement in renal artery was required; one unplanned aorto-uni-iliac device placed), with no primary type I or III endoleaks or conversions. A secondary technical success was achieved in all cases. The 30-day mortality was 2% and the first postoperative CTA documented 16 endoleaks (16%; 16 type II). One-year follow-up showed three iliac limb occlusions (3%), one infected stent graft (causing a type Ia endoleak), and five endovascular reinterventions (5%; three to treat iliac limb occlusions, one proximal extension cuff; and one stent in the renal artery). The 1-year all-cause mortality rate was 12% (12 patients) and the AAA-related mortality was 3%. The mean AAA size was significantly smaller after 1 year (diameter, 54 ± 11.8 [32-80] mm; P < .01; volume, 173 ± 119 [42-1028] mL; P < .01), and one graft migration >5 mm and 13 endoleaks were noted (12 type II, 1 type I [neck dilatation]). CONCLUSION: The treatment of patients with AAAs with the Endurant stent graft seems to be successful and durable during the first year after EVAR. Despite the wider inclusion criteria for the Endurant, and with 19% of our patients treated outside the IFU, the AAA-related mortality, number of type I or III endoleaks, and reintervention rates are comparable to the results of other stent grafts.

Pulsatility in the iliac artery is significant at several levels: implications for EVAR.

PURPOSE: To evaluate the pulsatility of the iliac arteries and compare their distension at several levels that might influence preoperative stent-graft sizing and the long-term durability of stent-graft sealing and fixation. METHODS: Preoperative dynamic computed tomographic angiography (CTA) scans of 30 patients (24 men; median age 75 years, range 60-85) with an abdominal aortic aneurysm and patent iliac arteries were included. The CTAs consisted of 8 images per heartbeat. Bilateral diameter and area changes per heartbeat were measured semi-automatically in the common iliac artery (CIA) at 3 levels: (A) 0.5 cm after the aortic bifurcation, (B) in the middle of the CIA, and (C) 0.5 cm proximal to the iliac bifurcation. Pulsatility was defined as the largest difference in area and average diameter change over 180 axes per heartbeat. Pulsatility at the 3 levels was compared, and the intraobserver variability of the method was calculated according to Bland and Altman. RESULTS: The mean area increases in the CIAs at levels A, B, and C were 12.5% (16.3 mm²), 11.2% (13.6 mm²), and 9.6% (12.6 mm²), respectively, and the mean iliac diameter increases were 9.2% (1.1 mm), 8.5% (1.0 mm), and 8.1% (1.0 mm). The iliac distension was statistically significant at all levels. The iliac distension at level A was statistically significantly larger than the distension at level C. The intraobserver variability was 13.3 mm² for area and 0.6 mm for diameter measurements. CONCLUSION: The pulsatility in the iliac arteries is statistically significant at several levels relevant to endovascular aneurysm repair. The distension of the iliac artery possibly decreases more distally, which might encourage the extension of stent-grafts to the internal iliac artery.

Fenestration of an iatrogenic aortic dissection after endovascular aneurysm repair.

PURPOSE: To present a case of percutaneous fenestration of a type B aortic dissection after endovascular aneurysm repair (EVAR). CASE REPORT: An 82-year-old patient with an earlier conventionally inserted aortobi-iliac prosthesis presented with a proximal anastomotic pseudoaneurysm, which was excluded successfully by EVAR. Standard follow-up computed tomographic angiography (CTA) 48 hours after the procedure, however, revealed a type B aortic dissection. Despite conservative antihypertensive therapy, the patient developed abdominal and back pain, and intervention was indicated. Endovascular balloon fenestration of the intimal flap was performed, resulting in relief of pain even though the false lumen remained patent. At 8 months after the procedure, the patient was symptom free, and CTA showed no progression of the persistent type B dissection. CONCLUSION: Percutaneous fenestration can be used as a therapy of first choice in patients with an acute aortic dissection post EVAR.

Thoracic aortic pulsatility decreases during hypovolemic shock: implications for stent-graft sizing.

PURPOSE: To investigate the thoracic aortic pulsatility during hypovolemic shock in an experimental porcine model. METHODS: The circulating blood volume of 7 healthy Yorkshire pigs was gradually lowered until the subjects had lost 40% of their normal blood volume. Intravascular ultrasound was used to assess the aortic pulsatility in normovolemic and hypovolemic state at the level of the ascending and descending thoracic aorta. RESULTS: The mean aortic pulsatility at the level of the ascending aorta decreased from 15.9% ± 7.2% (range 6.3%-25.7%) in normovolemia to 6.2% ± 2.8% (range 2.9%-10.7%, p = 0.018) in hypovolemia. At the level of the descending thoracic aorta, the mean aortic pulsatility decreased from 8.7% ± 2.8% (range 4.4%-12.2%) at baseline to 5.6% ± 2.5% (range 1.5%-9.5%, p = 0.028) in hypovolemia. The maximum mean aortic diameter, obtained in cardiac systole, was significantly smaller as well at both evaluated levels during hypovolemic shock compared with the mean diameter in normovolemia. CONCLUSION: The thoracic aortic diameter and pulsatility decreased significantly during hypovolemic shock in this porcine model, most impressively at the level of the ascending aorta. Electrocardiographically-gated imaging may not be necessary for hypovolemic patients with acute aortic disease requiring endovascular repair because of the minimal aortic pulsatility.

Treatment of a recurrent false aneurysm of the femoral artery by stent--graft placement from the brachial artery.

An anastomotic false aneurysm is a well known complication after femoral artery surgery. Open surgical repair is the treatment of choice for anastomotic femoral aneurysms, but this can be challenging, unsuccessful, or even impossible. Endovascular repair is an alternative in these cases, but the delivery of a stent--graft in the femoral artery can be difficult. We report the case of a patient with a recurrent left femoral artery anastomotic false aneurysm, treated twice by open exclusion, and finally excluded successfully by a stent--graft that was inserted through the left brachial artery.

Tips and techniques for optimal stent graft placement in angulated aneurysm necks.

An increasing number of patients with severely angulated abdominal aortic aneurysm (AAA) necks are being treated by endovascular aneurysm repair (EVAR). Optimal preprocedural planning and investigation of the AAA morphology is essential to achieve a successful EVAR in these patients. In this article, we discuss specific problems that can be encountered during preoperative planning in relation to periprocedural stent graft deployment in patients with angulated AAA necks and offer potential solutions for these problems.

A ruptured aneurysm after stent graft puncture during computed tomography-guided thrombin injection.

Type II endoleaks occur in 5% to 10% of patients who are treated by endovascular aneurysm repair. A persistent type II endoleak combined with documented aneurysm expansion is generally considered an indication for intervention. Thrombin injection directly into the aneurysm sac is described as a safe and efficient treatment option. We present a patient with a ruptured aneurysm caused by a puncture of the stent graft during computed tomography-guided thrombin injection. This case highlights a possible harmful complication of thrombin injection and emphasizes the need for caution while performing such a procedure.

Validation of a new standardized method to measure proximal aneurysm neck angulation.

PURPOSE: This study presented and validated a new standardized method for the measurement of the aortic angulation in patients with abdominal aortic aneurysms (AAA) and quantified the observer variability. METHODS: A standardized method to quantify aortic angulation was introduced. To measure aortic angulation, a center lumen line (CLL) of the aorta was made, and a three-dimensional (3D) aortic reconstruction was obtained. The 3D reconstruction was turned 360 degrees perpendicular to the CLL in the middle of the flexure. The sharpest angle of the CLL was considered the true angle of the aortic axis. The computed tomography angiography data sets of 20 patients scheduled for endovascular aneurysm repair (EVAR) were obtained. The angles between the suprarenal aorta and the aneurysm neck (alpha) and between the aneurysm neck and sac (beta) were measured. Two observers independently measured the angles. Differences of each pair of measurements were plotted against their mean and intraobserver and interobserver variabilities were calculated according to Bland and Altman. RESULTS: The intraobserver mean difference for angle alpha was -0.2 degrees (-0.5%), with a repeatability coefficient (RC) of 6.4 degrees (20.2%), and 0.6 degrees (1.4%) for angle beta, with a RC of 6.2 degrees (13.4%). The interobserver mean difference for angle alpha was -1.5 degrees (-4.5%), with a RC of 6.9 degrees (22.0%), and -0.2 degrees (-0.4%) for angle beta, with a RC of 7.4 degrees (16.0%). No significant differences were observed between the observers. CONCLUSION: The presented technique to objectively quantify the angulation of the aneurysm neck is easy to perform and reliable. This method showed good intraobserver and interobserver variability and should therefore be the standard when measuring and reporting aortic angulation.

Aortic neck angulations decrease during and after endovascular aneurysm repair.

PURPOSE: To investigate whether suprarenal and infrarenal aortic neck angles change immediately after endovascular aneurysm repair (EVAR) or during follow-up. A change in aortic angulation influences the proximal stent-graft sealing and fixation zone, thereby possibly influencing the long-term results of EVAR. METHODS: Forty-three EVAR patients (39 men; mean age 73 years, range 62-85) with preoperative, postoperative, and 1, 2, and 3-year follow-up computed tomographic angiography (CTA) data were selected from our center's vascular database. The suprarenal and infrarenal angulations on all CTAs were measured using a standardized 3-dimensional centerline method, which has a repeatability coefficient of 6.4° (20.2%) for the suprarenal angle and 6.2° (13.4%) for the infrarenal angle. Repeated measures analysis was used to test the effect of angulation over time, followed by a post-hoc analysis. RESULTS: The mean suprarenal angulation was 28°±16° preoperatively, 22°±16° postoperatively, 19°±15° after 1 year, 17°±14° after 2 years, and 16±13° after 3 years (mean difference 5°, 9°, 11°, and 12°, respectively). The aortic suprarenal angle decrease was significant (all p<0.01) compared with the preoperative measurements at all time points. The mean infrarenal angulation was 50°±18° preoperatively and changed to 41°±15° postoperatively, to 39°±14° after 1 year, to 38°±14° after 2 years, and to 36°±14° after 3 years (mean difference 8°, 11°, 11° and 13°, respectively). The infrarenal aortic angle decrease was significant (all p<0.01) compared with the preoperative measurements at all time points. CONCLUSION: The aortic suprarenal and infrarenal angles decrease during EVAR and in the years after this procedure.

Proximal aortic perforation after endovascular repair of a type B dissection in a patient with Marfan syndrome.

Several successful cases of endovascular treatment of type B dissections in patients with Marfan syndrome have been reported. In our patient with Marfan syndrome, a type B dissection was successfully treated endovascularly. Three weeks after this procedure, a computed tomographic angiography (CTA) revealed a perforation of the aortic wall distal to the left subclavian artery by a bare strut of the stent graft. A second stent graft was placed to treat this complication. In patients with Marfan syndrome, complications might be prevented by using stent grafts specifically developed to treat dissections. However, specific complications, eg, perforation, must be taken into account and patients have to be followed attentively.

Potential value of aneurysm sac volume measurements in addition to diameter measurements after endovascular aneurysm repair.

PURPOSE: To investigate the value of aneurysm sac volume measurement in addition to diameter measurements based on computed tomographic angiography (CTA) after endovascular aneurysm repair (EVAR). METHODS: Interrogation of a vascular database identified 56 patients (51 men; median age 77 years, range 59-92), 28 with an endoleak and 28 without, who had digital CTA data available at baseline (first postoperative scan) and at 1 and 2 years after EVAR. Total aneurysm volume, transverse maximum diameter (TMD), and orthogonal maximum diameter (OMD; perpendicular to the aortic center lumen line) were compared for all patients and between those with and without endoleak. Differences of 5% for volume and 5 mm for diameters were considered a significant change. Kappa statistics were used to compare measurements. RESULTS: Volumetry detected aneurysm growth in 32 (24%) of 131 scans, which was reflected by TMD in 12 (38%) and by OMD in 14 (44%). Eighteen scans with increasing aneurysm volume were measured in patients with endoleaks, which was documented by TMD in 6 (33%) and by OMD in 8 (44%). Fourteen volume increases were measured in patients without endoleak; both TMD and OMD documented only 43%. Volumetry detected aneurysm shrinkage in 71 (54%) of 131 scans [detected by TMD in 38 (54%) and by OMD in 37 (52%)]. Thirty-two volume decreases were measured in patients with an endoleak, noted by TMD in 18 (56%) and OMD in 14 (44%). Thirty-nine scans showed decreasing volumes in patients without endoleaks; the TMD corresponded in 20 (51%) and the OMD in 23 (59%). The kappa agreements for volume increase were 0.42 (TMD) and 0.35 (OMD) and for volume decrease 0.48 (TMD) and 0.47 (OMD); different thresholds of change produced similar moderate-range kappa values (0.3-0.6). CONCLUSION: Volumetry detects sac size changes that are not reflected in diameter measurements. Vice versa, diameters can increase without a total volume increase, which might indicate a variety of morphological aneurysm changes. The agreement between volume and diameter measurements using different cutoff values is equally moderate. Volume measurements should be performed in addition to diameter measurements.

Number of entry tears is associated with aortic growth in type B dissections.

BACKGROUND: Aortic growth rate in acute type B aortic dissection (ABAD) is a significant predictor for aortic complications and death. To improve the overall outcome, radiologic predictors might stratify patients who benefit from successful medical management vs those who require intervention. This study investigated whether the number of identifiable entry tears in ABAD patients is associated with aortic growth. METHODS: ABAD patients with uncomplicated clinical conditions and therefore treated with medical therapy were evaluated. Those with a computed tomography angiography (CTA) obtained at clinical presentation and a subsequent CTA obtained at least 90 days after medical treatment were included (2005 to 2010). The CTAs were investigated for the number of entry tears between the true and false lumen. Diameters of the dissected aortas were measured at five levels on the baseline and on the last available follow-up CTA, and annual aortic growth rates were calculated. The number of entry tears in these patients and the location in the aorta were compared with the aortic growth rate. RESULTS: Included were 60 patients who presented with 243 dissected segments. Mean growth rates during follow-up (median, 23.2; range, 3 to 132 months) were significantly higher in patients with 1 entry tear (5.6 ± 8.9 mm) than in those with 2 (2.1 ± 1.7 mm; p = 0.001) and 3 entry tears (mean 2.2 ± 4.1; p = 0.010). The distance of the primary entry tear from the left subclavian artery did not have an effect on the aortic growth rate (median, 38; interquartile range, 24 to 137 mm; p = 0.434). CONCLUSIONS: The number of entry tears in ABAD patients detected on the first CTA after clinical presentation is a significant predictor for aortic growth. Patients with 1 entry tear at presentation show a higher growth rate than other patients and might benefit from more strict surveillance or early prophylactic intervention.