Three-Dimensional Workstation is Useful for Measuring the Correct Size of Abdominal Aortic Aneurysm Diameters

The outcomes and cost analysis of open repair and endovascular aneurysm repair for abdominal aortic aneurysms: a single-center experience in Japan

PURPOSE

Japan has adopted its own reimbursement system, which differs from other countries in terms of its diagnostic procedure combination (DPC) methods. However, there are few reports on the cost analysis of open repair and endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms in Japan. We aimed to evaluate the long-term outcomes and cost-effectiveness of these two procedures.

METHODS

This study included patients who underwent open repair (n = 224) and EVAR (n = 87) between January 2012 and December 2022. After propensity score matching, we compared the two groups.

RESULTS

The drug and blood products, procedures, and DPC costs were significantly higher in the open repair group (p < 0.001) than in the EVAR group. The surgical equipment and total costs were significantly higher in the EVAR group than in the open repair group (p < 0.001). There was no significant difference in the 5-year survival rate (88.5% in the open repair group vs. 72.0% in the EVAR group; p = 0.33) and freedom from re-intervention rate at 5 years (93.1% in the open repair group vs. 89.9% in the EVAR group; p = 0.15) between the two groups.

CONCLUSIONS

Open repair is more cost-effective than EVAR. The cost-effectiveness of EVAR may therefore depend on the cost of the endograft.

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.

ACR Appropriateness Criteria® Pulsatile Abdominal Mass, Suspected Abdominal Aortic Aneurysm: 2023 Update

Abdominal aortic aneurysm (AAA) is defined as abnormal dilation of the infrarenal abdominal aortic diameter to 3.0 cm or greater. The natural history of AAA consists of progressive expansion and potential rupture. Although most AAAs are clinically silent, a pulsatile abdominal mass identified on physical examination may indicate the presence of an AAA. When an AAA is suspected, an imaging study is essential to confirm the diagnosis. This document reviews the relative appropriateness of various imaging procedures for the initial evaluation of suspected AAA. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The correlation between different ultrasound planes and computed tomography measures of abdominal aortic aneurysms

Introduction

Ultrasound measurements of the aorta are typically taken in the axial plane, with the transducer perpendicular to the aorta, and diameter measurements are obtained by placing the callipers from the anterior to the posterior wall and the transverse right to the left side of the aorta. While the 'conventional' anteroposterior walls in both sagittal and transverse plains may be suitable for aneurysms with less complicated geometry, there is controversy regarding the suitability of this approach for complicated, particularly tortuous aneurysms, as they may offer a more challenging situation. Previous work undertaken within our research group found that when training inexperienced users of ultrasound, they demonstrated more optimal calliper placement to the abdominal aorta when approached from a decubitus window to obtain a coronal image compared to the traditional ultrasound approach.

Purpose

To observe the level of agreement in real-world reporting between computed tomography (CT) and ultrasound measurements in three standard planes; transverse AP, sagittal AP and coronal (left to right) infra-renal abdominal aortic aneurysm (AAA) diameter.

Methodology

This is a retrospective review of the Otago Vascular Diagnostics database for AAA, where ultrasound and CT diameter data, available within 90 days of each other, were compared. In addition to patient demographics, the infrarenal aorta ultrasound diameter measurements in transverse AP and sagittal AP, along with a coronal decubitus image of the aorta was collected. No transverse measurement was performed from the left to the right of the aorta.

Results

Three hundred twenty-five participants (238 males, mean age 76.4 ± 7.5) were included. Mean ultrasound outer to the outer wall, transverse AP and sagittal AP diameters were 48.7 ± 10.5 mm and 48.9 ± 9.9 mm, respectively. The coronal diameter measurement of the aorta from left to right was 53.9 ± 12.8 mm in the left decubitus window. The mean ultrasound max was 54.3 ± 12.6 mm. The mean CT diameter measurement was 55.6 ± 12.7 mm. Correlation between the CT max and ultrasound max was r 2 = 0.90, and CT with the coronal measurement r 2 = 0.90, CT and AP transverse was r2=0.80, and CT with AP sagittal measurement was r 2 = 0.77.

Conclusion

The decubitus ultrasound window of the abdominal aorta, with measurement of the coronal plane, is highly correlated and in agreement with CT scanning. This window may offer an alternative approach to measuring the infrarenal abdominal aortic aneurysm and should be considered when performing surveillance of all infra-renal AAA.

Early and Late Mortality Predictors in Patients with Acute Aortic Dissection Type B

BACKGROUND/AIM

Despite technological advances in diagnosis and treatment, in-hospital mortality with acute aortic dissection type B is still about 11%. The purpose of this study was to assess the risk factors for early and long-term adverse outcomes in patients with acute aortic dissection type B treated medically or with conventional open surgery.

METHODS

The present study included 104 consecutive patients with acute aortic dissection type B treated in our Center from January 1st, 1998 to January 1st, 2007. Patient demographic and clinical characteristics as well as in-hospital complications were reviewed. Univariate and multivariate testing was performed to identify the predictors of in-hospital (30-day) and late (within 9 years) mortality.

RESULTS

92 (88.5%) patients were treated medically, while 12 (11.5%) patients with complicated acute aortic dissection type B were treated by open surgical repair. In-hospital complications occurred in 35.7% patients, the most often being acute renal failure (28%), hypotension/shock (24%), mesenteric ischemia (12%), and limb ischemia (8%). The in-hospital mortality rate was 15.7% and the 9-year mortality rate was 51.9%. Independent predictors of early mortality in patients with acute aortic dissection type B were uncontrolled hypertension (HR-20.69) and a dissecting aorta diameter >4.75 cm (HR-6.30). Independent predictors of late mortality were relapsing pain (HR-7.93), uncontrolled hypertension (HR-7.25), and a pathologic difference in arterial blood pressure (>20 mmHg) (HR-5.33).

CONCLUSION

Knowledge of key risk factors may help with a better choice of treatment and mortality reduction in acute aortic dissection type B patients.

Performance of a deep learning tool to detect missed aortic dilatation in a large chest CT cohort

Purpose

Thoracic aortic (TA) dilatation (TAD) is a risk factor for acute aortic syndrome and must therefore be reported in every CT report. However, the complex anatomy of the thoracic aorta impedes TAD detection. We investigated the performance of a deep learning (DL) prototype as a secondary reading tool built to measure TA diameters in a large-scale cohort.

Material and methods

Consecutive contrast-enhanced (CE) and non-CE chest CT exams with “normal” TA diameters according to their radiology reports were included. The DL-prototype (AIRad, Siemens Healthineers, Germany) measured the TA at nine locations according to AHA guidelines. Dilatation was defined as &gt;45 mm at aortic sinus, sinotubular junction (STJ), ascending aorta (AA) and proximal arch and &gt;40 mm from mid arch to abdominal aorta. A cardiovascular radiologist reviewed all cases with TAD according to AIRad. Multivariable logistic regression (MLR) was used to identify factors (demographics and scan parameters) associated with TAD classification by AIRad.

Results

18,243 CT scans (45.7% female) were successfully analyzed by AIRad. Mean age was 62.3 ± 15.9 years and 12,092 (66.3%) were CE scans. AIRad confirmed normal diameters in 17,239 exams (94.5%) and reported TAD in 1,004/18,243 exams (5.5%). Review confirmed TAD classification in 452/1,004 exams (45.0%, 2.5% total), 552 cases were false-positive but identification was easily possible using visual outputs by AIRad. MLR revealed that the following factors were significantly associated with correct TAD classification by AIRad: TAD reported at AA [odds ratio (OR): 1.12, p &lt; 0.001] and STJ (OR: 1.09, p = 0.002), TAD found at &gt;1 location (OR: 1.42, p = 0.008), in CE exams (OR: 2.1–3.1, p &lt; 0.05), men (OR: 2.4, p = 0.003) and patients presenting with higher BMI (OR: 1.05, p = 0.01). Overall, 17,691/18,243 (97.0%) exams were correctly classified.

Conclusions

AIRad correctly assessed the presence or absence of TAD in 17,691 exams (97%), including 452 cases with previously missed TAD independent from contrast protocol. These findings suggest its usefulness as a secondary reading tool by improving report quality and efficiency.

Imaging and Surveillance of Chronic Aortic Dissection: A Scientific Statement From the American Heart Association

All patients surviving an acute aortic dissection require continued lifelong surveillance of their diseased aorta. Late complications, driven predominantly by chronic false lumen degeneration and aneurysm formation, often require surgical, endovascular, or hybrid interventions to treat or prevent aortic rupture. Imaging plays a central role in the medical decision-making of patients with chronic aortic dissection. Accurate aortic diameter measurements and rigorous, systematic documentation of diameter changes over time with different imaging equipment and modalities pose a range of practical challenges in these complex patients. Currently, no guidelines or recommendations for imaging surveillance in patients with chronic aortic dissection exist. In this document, we present state-of-the-art imaging and measurement techniques for patients with chronic aortic dissection and clarify the need for standardized measurements and reporting for lifelong surveillance. We also examine the emerging role of imaging and computer simulations to predict aortic false lumen degeneration, remodeling, and biomechanical failure from morphological and hemodynamic features. These insights may improve risk stratification, individualize contemporary treatment options, and potentially aid in the conception of novel treatment strategies in the future.

Computed tomography in the size measurement of gastric gastrointestinal stromal tumors: Implication to risk stratification and "wait-and-see" tactics

INTRODUCTION

This study aimed to compare the radiologic size of gastric gastrointestinal stromal tumors (GISTs) on computed tomography (CT) with the pathologic size in a Chinese population, and elucidate the potential significance of the CT size in the preoperative risk stratification.

MATERIALS AND METHODS

The study enrolled 314 patients treated by endoscopic/surgical resection of gastric lesions that proved postoperatively to be GISTs. Bland-Altman analysis and intraclass correlation coefficient (ICC) were adopted to assess the size agreement between CT and pathology. Independent predictors of risk category underestimation and the optimal cut-off value of CT size were determined by logistic regression analysis and the receiver operating characteristic (ROC) curve.

RESULTS

CT underestimated gastric GISTs size by 0.30 cm [95% confidence interval (CI): (-0.42, - 0.19); p < 0.001]. In the subgroup analysis, the size underestimation was 0.10 cm in GISTs ≤ 5 cm [95% CI: (-0.19, -0.01); p = 0.024]; and 0.75 cm in GISTs >5 cm [95% CI: (-1.05, 0.45), p < 0.001]. Though ICC values showed well reliability for the corresponding pathologic size, with 0.95 in all size, 0.86 in size ≤ 5 cm, and 0.92 in size >5 cm respectively. Risk underestimation by CT imaging mainly occurred in gastric GISTs with smaller size (≤5 cm; p = 0.010) and lower mitotic index (≤5 per 50 high-power fields; p = 0.011). CT size of 3.65 cm was defined as an absolute cut-off to differentiate intermediate/high-risk patients from low-risk group, with 87.5% sensitivity at a specificity of 57.8%.

CONCLUSION

Preoperative CT underestimated the mean size by 0.30 cm in gastric GISTs. A CT size of 3.65 cm would facilitate the selection of potential intermediate/high-risk patients, instant intervention should be encouraged in the absence of contraindications.

Clinical Comparison between Early and Late Spontaneous Sac Shrinkage after Endovascular Aortic Aneurysm Repair

BACKGROUND

Early spontaneous shrinkage (ESS) of abdominal aortic aneurysm (AAA) within 1 year after endovascular aortic aneurysm repair (EVAR) could be a predictor of durable success. However, late spontaneous shrinkage (LSS) during longer follow-up has not been well addressed. We compared late complications of ESS and LSS.

METHODS

Our series of elective EVAR for infrarenal AAA from June 2007 to December 2017 was reviewed. Patients with ≥1 year of follow-up with computed tomography (CT) studies were included. Patients with any reintervention within 1 year were excluded. Spontaneous shrinkage (SpS) was defined as a diameter reduction ≥10 mm without any reintervention. ESS was defined as SpS within 1 year, and LSS was defined as SpS occurring after 1 year of follow-up. Aneurysms that became larger than the original size after SpS were defined as re-expansion. Late complications (re-expansion, reintervention, and aneurysm-related death) and related factors were compared between ESS and LSS.

RESULTS

A total of 495 patients were enrolled. Median follow-up was 43 months [24-67, interquartile range (IQR)]. Among patients, 126 ESS and 55 LSS occurred. The cumulative rates of SpS were 25.7±2.0%, 37.4±2.4%, and 47.3±3.7% at 1, 3, and 7 years, respectively. There was 1 re-expansion and 6 reinterventions during further follow-up after SpS. The rates of freedom from late complications at 5 years were not significantly different between ESS (89.2±4.0%) and LSS (95.8±4.1%) (P = 0.465). Regression analysis revealed that the Zenith device was significantly related to ESS compared to the Excluder (P = 0.006) and Endurant (P = 0.040) . More than 6 preoperative patent lumbar arteries negatively correlated with ESS (P = 0.023). However, these factors had no significant impact on LSS.

CONCLUSIONS

The rates of late complications after SpS were comparable between ESS and LSS. Patients with delayed sac shrinkage with a reduction in diameter ≥10 mm should expect the same durable success as patients with quick shrinkage.

Abdominal aortic aneurysm measurement at CT/MRI: potential clinical ramifications of non-standardized measurement technique and importance of multiplanar reformation

Accurate and reproducible measurement of abdominal aortic aneurysm (AAA) size is an essential component of patient management, and most reliably performed at CT using a multiplanar reformat (MPR) strategy. This approach is not universal, however. This study aims to characterize the measurement error present in routine clinical assessment of AAAs and the potential clinical ramifications. Patients were included if they had AAA assessed by CT and/or MRI at two time points at least 6 months apart. Clinical maximal AAA diameter, assessed by non-standardized methods, was abstracted from the radiology report at each time point and compared to the reference aneurysm diameter measured using a MPR strategy. Discrepancies between clinical and reference diameters, and associated aneurysm enlargement rates were analyzed. Two hundred thirty patients were included, with average follow-up 3.3±2.5 years. When compared to MPR-derived diameters, clinical aneurysm measurement inaccuracy was, on average, 3.3 mm. Broad limits of agreement were found for both clinical diameters [-6.7 to +6.5 mm] and aneurysm enlargement rates [-4.6 to +4.2 mm/year] when compared to MPR-based measures. Of 78 AAAs measuring 5-6 cm by the MPR method, 21 (26.9%) were misclassified by the clinical measurement with respect to a common repair threshold (5.5 cm), of which 5 were misclassified as below, and 16 were misclassified as above the threshold. The clinical use of non-standardized AAA measurement strategies can lead to incorrect classification of AAAs as larger or smaller than the commonly accepted repair threshold of 5.5 cm and can induce large errors in quantification of aneurysm enlargement rate.

Low correlation between biometric parameters, cardiovascular risk factors and aortic dimensions by computed tomography coronary angiography

To analyze the relationship between aortic measures and biometric parameters in a large cohort of consecutive patients undergoing computed tomography coronary angiography.1170 patients (717 men/453 women) performing computed tomography coronary angiography for coronary evaluation were retrospectively evaluated. Aortic diameters and areas were measured at reproducible anatomic landmarks, perpendicular to the axis of vessel, at the level of the aortic root (AoR), the sinotubular junction (STJ), and the tubular ascending aorta (TAo). Biometric parameters and cardiovascular risk factors were recorded.The average values of AoR, STJ, and TAo were 35.63 ± 5.00 mm, 30.56 ± 4.82 mm, 35.07 ± 5.84 mm. Hypertension was significantly associated with aortic dimensions.Aortic measures were significantly different between men and women (37.56 ± 4.77 mm vs 32.58 ± 3.68 mm for AoR, 31.88 ± 4.84 mm vs 28.47 ± 3.98 mm for STJ and 35.93 ± 5.86 mm vs 33.70 ± 5.54 mm for TAo) (P < .001) and linearly increased with age. Low Spearman correlation coefficients were found and the correlation of TAo diameters with age displayed the highest values (ρ = 0.372 for male and ρ = 0.373 for female, P < .001). Multiple linear regression analysis models were compared by R. The best model used body surface area (BSA) and age as independent variables and TAo diameter as dependent variable (R = 0.29 for AoR; R = 0.21 for STJ, and R = 0.20 for TAo).In conclusion, in our population low correlation between aortic dimensions and biometric parameters highlights the difficulty of identifying normal ranges, as well as issues related to normalization using conventional biometric parameters.

A comparison of aortic root measurements by echocardiography and computed tomography

OBJECTIVES

The aim of the study is to evaluate an optimal way to assess the dimensions of the aortic root and each of the sinuses of Valsalva and examine how a single measurement in 1 plane (echocardiography or 2-dimensional computed tomography) can underestimate the maximum dimension of the aortic root.

METHODS

Computed tomography and transthoracic echocardiography images of the aortic root and ascending aorta of 112 patients were analyzed. The minimum and maximum aortic root dimensions, the root perimeter, and the total area of all 3 sinuses of Valsalva were measured on a plane perpendicular to the long axis of the aorta using 3-dimensional multiplanar reconstruction. Moreover, the maximum root dimension was compared with the measurements obtained from the echocardiography and 2-dimensional computed tomography angiography measurements.

RESULTS

The difference in the measurements of the minimum and maximum root dimension was 5.4 ± 3.2 mm (range, 0-21 mm, P < .0001) and was significantly larger in patients with bicuspid aortic valves compared with those with tricuspid valves (6.3 ± 4 mm, range, 0-21 mm vs 4.9 ± 2.6 mm, range, 0-15 mm, P = .036). The maximum root dimension measured in 3-dimensional multiplanar reconstruction (49.1 ± 9.0 mm) differed significantly from the root dimension measured in transthoracic echocardiography in the parasternal long-axis view (44.8 ± 8.4 mm) and 2-dimensional computed tomography (axial plane: 45.5 ± 9.0 mm, coronal plane: 46.1 ± 8.8 mm, sagittal plane: 45.1 ± 8.9 mm) (P < .001).

CONCLUSIONS

The difference in the measurements of the minimum and maximum aortic root dimensions is significant and may exceed 20 mm, especially in patients with bicuspid aortic valves. Therefore, aortic root dimensions can be significantly underestimated with the measurement (echocardiography, computed tomography angiography) performed in only 1 plane.

Repair of abdominal aortic aneurysms: preoperative imaging and evaluation

Imaging is a critical component of the pre-procedure evaluation and planning of endovascular aneurysm repair (EVAR). Imaging is the mainstay for proper assessment of procedural candidacy, relevant vascular anatomy, device selection, and surgical approach. Computed tomography angiography (CTA) has long been considered the preferred modality for pre-operative imaging and evaluation prior to EVAR. Recently, advances in image quality and software technology have further enhanced the proceduralist's ability to plan and perform EVAR. In this review, we highlight the current state of the art to provide interventionalists a contemporary assessment of the available tools for pre-operative imaging and evaluation prior to EVAR.

Non-contrast MR angiography using three-dimensional balanced steady-state free-precession imaging for evaluation of stenosis in the celiac trunk and superior mesenteric artery: a preliminary comparative study with computed tomography angiography

OBJECTIVE

Although non-contrast MR angiography (NC-MRA) is well established for the evaluation of renal artery stenosis, its usefulness in the evaluation of other abdominal aortic branches remains to be studied. This study aimed at evaluating the image quality and diagnostic accuracy of NC-MRA using a three-dimensional balanced steady-state free-precession sequence in identifying stenosis in the celiac trunk (CTR) and superior mesenteric artery (SMA) as compared with CT angiography (CTA) as the reference standard.

METHODS

41 patients underwent both NC-MRA and CTA of the abdominal aorta. Two radiologists analyzed the quality of the images (diagnostic vs non-diagnostic) and the performance (accuracy, sensitivity and specificity) of NC-MRA for the identification of arterial stenosis. Kappa tests were used to determine the interobserver agreement and the intermethod agreement between NC-MRA and CTA.

RESULTS

NC-MRA provided diagnostic quality images of the CTR and SMA in 87.8% and 90.2% of cases, respectively, with high interobserver agreement (kappa 0.95 and 0.80, respectively). For stenosis assessment, NC-MRA had a sensitivity of 100%, a positive-predictive value of 50% and a negative-predictive value of 100% for both segments, with accuracies of 88.8% for the CTR and 94.5% for the SMA.

CONCLUSION

NC-MRA is an accurate method for detecting stenosis in the CTR and SMA. Advances in knowledge: Data from this study suggest that MR angiography with balanced steady-state free-precession sequence is a viable non-contrast alternative for stenosis evaluation of these branches in patients for whom a contrast-enhanced examination is contraindicated.

Low Serum Levels of EPA are Associated with the Size and Growth Rate of Abdominal Aortic Aneurysm

Aim: Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to reduce the risk of cardiovascular disease. However, whether omega-3 PUFAs are involved in the pathogenesis of abdominal aortic aneurysms (AAA) remains unclear.

Methods: We analyzed 67 consecutive patients admitted for the elective surgical repair of AAA. We investigated the association of serum EPA and DHA levels as well as the EPA/AA ratio with the size of AAA assessed using three-dimensional reconstructed computed tomography images.

Results: Mean patient age was 70 ± 9 years and 60 patients were male. Serum EPA and DHA levels were 75.2 ± 35.7 µg/mL and 146.1 ± 48.5 µg/mL, respectively. EPA/AA ratio was 0.44 ± 0.22, which was lower than those in healthy Japanese subject and equivalent to those in Japanese patients with coronary artery disease as previously reported. Mean of the maximum AAA diameter was 56.4 ± 8.9 mm, and serum EPA levels and EPA/AA ratio negatively correlated with it (r = −0.32 and r = −0.32, respectively). Multiple liner regression analysis showed that EPA levels were significant independent factor contributing to the maximum AAA diameter. Furthermore, low serum EPA levels and low EPA/AA ratio were significantly associated with the growth rate of AAA diameter (r = −0.43 and r = −0.33, respectively).

Conclusion: EPA levels in patients with AAA were relatively low. Low serum EPA levels and EPA/AA ratio were associated with the size and growth rate of AAA.

The Relationship between Temporal Changes in Proximal Neck Angulation and Stent-Graft Migration after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

In recent years, endovascular abdominal aortic aneurysm repair (EVAR) for treating abdominal aortic aneurysms (AAA) has become quite prevalent in Japan. Though little information is available about temporal changes in proximal neck angulation due to the difficulties encountered in measuring the angle. Therefore, we examined temporal changes in proximal neck angulation and its relationship to stent-graft migration after EVAR.

METHODS

Between June 2007 and March 2010, 159 patients underwent EVAR for treatment of fusiform AAAs at our hospital. This study focuses on the 80 patients among this group whose treatment sites and subsequent stent grafts were examined by contrast computed tomographic angiography before surgery, directly after surgery (within 4 days), as well as 1 year and 2 years thereafter. We created curved planar reconstruction (CPR) images and measured the length of migration and neck angle using our method.

RESULTS

At 2 years after EVAR, the average length of proximal landing zone was 21.4 ± 9.2 mm. The average length of stent migration after 2 years was 1.41 ± 2.68 mm. The average neck angle was 33.9° preoperatively and 29.9° directly after surgery yielding a significant difference. However, 1 and 2 years after surgery the average neck angle was 28.2° and 28.4°, respectively. The number of patients experiencing a change >6° in the angle of the proximal neck between the preoperative condition and that directly after surgery was 16 (34.8%) with the use of Zenith stent grafts (n = 46) and 14 (41.2%) with the use of Excluder stent grafts (n = 34). There was no correlation between the proximal neck angle and migration of the proximal stent graft. In addition, there was no correlation between the changes in proximal neck angle and the secondary intervention rate and the occurrence of endoleak.

CONCLUSIONS

There was a significant change in the neck angle between the preoperative condition and the immediate postoperative condition. However, there was no clear relationship found between the angle of the neck and the proximal stent-graft migration. Postoperative changes in the proximal neck angle just after EVAR and subsequent temporal changes during a 2-year follow-up period do not appear to predict stent-graft migration, secondary intervention rates, or the occurrence of endoleak.

The Mystery of the Z-Score

Reliable methods for measuring the thoracic aorta are critical for determining treatment strategies in aneurysmal disease. Z-scores are a pragmatic alternative to raw diameter sizes commonly used in adult medicine. They are particularly valuable in the pediatric population, who undergo rapid changes in physical development. The advantage of the Z-score is its inclusion of body surface area (BSA) in determining whether an aorta is within normal size limits. Therefore, Z-scores allow us to determine whether true pathology exists, which can be challenging in growing children. In addition, Z-scores allow for thoughtful interpretation of aortic size in different genders, ethnicities, and geographical regions. Despite the advantages of using Z-scores, there are limitations. These include intra- and inter-observer bias, measurement error, and variations between alternative Z-score nomograms and BSA equations. Furthermore, it is unclear how Z-scores change in the normal population over time, which is essential when interpreting serial values. Guidelines for measuring aortic parameters have been developed by the American Society of Echocardiography Pediatric and Congenital Heart Disease Council, which may reduce measurement bias when calculating Z-scores for the aortic root. In addition, web-based Z-score calculators have been developed to aid in efficient Z-score calculations. Despite these advances, clinicians must be mindful of the limitations of Z-scores, especially when used to demonstrate beneficial treatment effect. This review looks to unravel the mystery of the Z-score, with a focus on the thoracic aorta. Here, we will discuss how Z-scores are calculated and the limitations of their use.

Relationship between the distal migration and length of the distal landing zone after endovascular aneurysm repair (EVAR)

BACKGROUND AND PURPOSE

Endovascular aneurysm repair (EVAR) is the main treatment for patients with abdominal aortic aneurysms. This study examines the relationship between the migration of the distal landing zone and the length of the landing zone.

MATERIALS AND METHODS

The subjects of this study were 36 patients who underwent contrast-enhanced computed tomography 1 year after EVAR. We constructed curved multi-planar reconstruction imaging and measured the length of migration, the angle of the common iliac artery, and the diameter of the distal landing zone.

RESULTS

The mean length of migration was 1.2 ± 1.7 mm. Fifty-four legs had a distal landing zone of over 15 mm and 18 legs had a distal landing zone of less than 15 mm. Four (7.4 %) of the 54 legs with a landing zone of over 15 mm and 3 (16.7 %) of the 18 legs with a landing zone of less than 15 mm had migration of over 3 mm. This difference was significant (P = 0.05).

CONCLUSION

The rate of migration on the distal landing zone 1 year after EVAR was reasonable when the length of the landing zone was about 15 mm. It is possible that significant migration can occur in patients with distal landing zones less than 10 mm in length.

Non-invasive volumetric assessment of aortic atheroma: a core laboratory validation using computed tomography angiography

Aortic atherosclerosis has been linked with worse peri- and post-procedural outcomes following a range of aortic procedures. Yet, there are currently no standardized methods for non-invasive volumetric pan-aortic plaque assessment. We propose a novel means of more accurately assessing plaque volume across whole aortic segments using computed tomography angiography (CTA) imaging. Sixty patients who underwent CTA prior to trans-catheter aortic valve implantation were included in this analysis. Specialized software analysis (3mensio Vascular™, Pie Medical, Maastricht, Netherlands) was used to reconstruct images using a centerline approach, thus creating true cross-sectional aortic images, akin to those images produced with intravascular ultrasonography. Following aortic segmentation (from the aortic valve to the renal artery origin), atheroma areas were measured across multiple contiguous evenly spaced (10 mm) cross-sections. Percent atheroma volume (PAV), total atheroma volume (TAV) and calcium score were calculated. In our populations (age 79.9 ± 8.5 years, male 52 %, diabetes 27 %, CAD 84 %, PVD 20 %), mean ± SD number of cross sections measured for each patient was 35.1 ± 3.5 sections. Mean aortic PAV and TAV were 33.2 ± 2.51 % and 83,509 ± 17,078 mm(3), respectively. Median (IQR) calcium score was 1.5 (0.7-2.5). Mean (SD) inter-observer coefficient of variation and agreement for plaque area among 4 different analysts was 14.1 (5.4), and the mean (95 % CI) Lin's concordance correlation coefficient was 0.79 (0.62-0.89), effectively simulating a Core Laboratory scenario. We provide an initial validation of cross-sectional volumetric aortic atheroma assessment using CTA. This proposed methodology highlights the potential for utilizing non-invasive aortic plaque imaging for risk prediction across a range of clinical scenarios.

CT angiography in the diagnosis of cardiovascular disease: a transformation in cardiovascular CT practice

Computed tomography (CT) angiography represents the most important technical development in CT imaging and it has challenged invasive angiography in the diagnostic evaluation of cardiovascular abnormalities. Over the last decades, technological evolution in CT imaging has enabled CT angiography to become a first-line imaging modality in the diagnosis of cardiovascular disease. This review provides an overview of the diagnostic applications of CT angiography (CTA) in cardiovascular disease, with a focus on selected clinical challenges in some common cardiovascular abnormalities, which include abdominal aortic aneurysm (AAA), aortic dissection, pulmonary embolism (PE) and coronary artery disease. An evidence-based review is conducted to demonstrate how CT angiography has changed our approach in the diagnosis and management of cardiovascular disease. Radiation dose reduction strategies are also discussed to show how CT angiography can be performed in a low-dose protocol in the current clinical practice.