Sex-Specific Morphometric Analysis of Ascending Aorta and Aortic Arch for Planning Thoracic Endovascular Aortic Repair: A Retrospective Cohort Study

OBJECTIVE

In many studies on aortic disease, women are underrepresented. The present study aims to assess sex-specific morphometric differences and gain more insight into endovascular treatment of the ascending aorta (AA) and arch.

METHODS

Electrocardiogram-gated cardiac computed tomography scans of 116 consecutive patients who were evaluated for transcatheter aortic valve replacement were retrospectively reviewed. Measurements of the AA and aortic arch were made in multiplanar views, perpendicular to the semi-automatic centerline. Multiple linear regression analysis was performed to identify predictors affecting AA and aortic arch diameter in men and women. Propensity score matching was used to investigate whether sex influences aortic morphology.

RESULTS

In both sexes, body surface area (BSA) was identified as a positive predictor and diabetes as a negative predictor for aortic diameters. In men, age was identified as a positive predictor and smoking as a negative predictor for aortic diameters. Propensity score matching identified 40 pairs. Systolic and diastolic mean diameters and AA length were significantly wider in men. On average, male aortas were 7.4% wider than female aortas, both in systole and diastole.

CONCLUSIONS

The present analysis demonstrates that, in women, increased BSA is associated with increased aortic arch diameters, while diabetes is associated with decreased AA and arch diameters. In men, increased BSA and age are associated with increased AA and arch diameters, while smoking and diabetes are associated with decreased AA and arch diameters. Men were confirmed to have 7.4% greater AA and arch diameters than women.

CLINICAL IMPACT

Men had 7.4% greater ascending aorta and arch diameters than women in a retrospective cohort, gated computed tomography-based study of 116 patients. Sex-specific differences in ascending aortic and arch size should be considered by aortic endovascular device manufacturers and physicians when developing ascending and arch endografts and planning aortic interventions.

Velocity-Domain Motion Quality Measures for Surgical Performance Evaluation and Feedback

Endovascular navigation proficiency requires a significant amount of manual dexterity from surgeons. Objective performance measures derived from endovascular tool tip kinematics have been shown to correlate with expertise; however, such metrics have not yet been used during training as a basis for real-time performance feedback. This paper evaluates a set of velocity-based performance measures derived from guidewire motion to determine their suitability for online performance evaluation and feedback. We evaluated the endovascular navigation skill of 75 participants using three metrics (spectral arc length, average velocity, and idle time) as they steered tools to anatomical targets using a virtual reality simulator. First, we examined the effect of navigation task and experience level on performance and found that novice performance was significantly different from intermediate and expert performance. Then we computed correlations between measures calculated online and spectral arc length, our “gold standard” metric, calculated offline (at the end of the trial, using data from the entire trial). Our results suggest that average velocity and idle time calculated online are strongly and consistently correlated with spectral arc length computed offline, which was not the case when comparing spectral arc length computed online and offline. Average velocity and idle time, both time-domain based performance measures, are therefore more suitable measures than spectral arc length, a frequency-domain based metric, to use as the basis of online performance feedback. Future work is needed to determine how to best provide real-time performance feedback to endovascular surgery trainees based on these metrics.

Important longitudinal and circumferential pulsatile changes in zone 0 of the aorta during the cardiac cycle

OBJECTIVES

Correct stent-graft sizing is important when planning for thoracic endovascular repair in zone 0. As the movements of the aorta are constantly evolving in longitudinal and circumferential directions during the cardiac cycle, the diameter may not be the only important measurement. The aim of this study is to measure the circumferential and longitudinal pulsatile changes throughout the cardiac cycle.

METHODS

Ninety-two patients, who were evaluated for transcatheter aortic valve replacement, were selected for this retrospective study. Their electrocardiogram-gated cardiac computed tomography was analysed. We identified the area, perimeter and diameter of the thoracic aorta in zone 0 and calculated the differences between these parameters at 3 locations in zone 0. The measurements were made in multiplanar views perpendicular to the semi-automatically created centreline in both systolic and diastolic phases.

RESULTS

The mean age of our study cohort was 77 ± 11 years. The mean change between systole and diastole of the area (mm2), perimeter (mm) and diameter (mm) were compared at 3 different locations in the ascending aorta: at the sinotubular junction (0.78 mm2 vs 0.89 mm vs 1.41 mm), mid-ascending (0.72 mm2 vs 0.68 vs 0.81 mm) and proximal edge of the brachiocephalic artery (0.76 mm2 vs 0.73 mm vs 0.73 mm). The change in percentage is the smallest in the area at the sinotubular junction compared to the perimeter and diameter (2.6% vs 3.1% vs 4.7%).

CONCLUSIONS

Changes in measurement of ascending aortic diameter with cardiac cycle are larger than measurement change in the area. This is especially more pronounced in zone 0A. For more accurate information on the morphometric changes, it may be necessary to measure the area when planning for thoracic endovascular repair to maximize results. A prospective study comparing these different measurements regarding the outcomes is advised by the authors to understand the clinical implications.

In the Fundamentals of Endovascular and Vascular Surgery model motion metrics reliably differentiate competency

OBJECTIVE

The Fundamentals of Endovascular and Vascular Surgery, a curriculum that includes an endovascular model for skills testing, aims to differentiate between competent and noncompetent performers. The aim of our study was to further validate the model and to test its reliability in assessing the performance of endovascular trainees in an uncontrolled setting.

METHODS

The model was tested exclusively in a virtual reality environment. On the basis of their endovascular experience, 52 participants were divided into three groups: novice (<50 endovascular cases), intermediate (50-500 endovascular cases), and expert (>500 endovascular cases). Performance was evaluated in four tasks, measuring the tool tip position and velocity on the virtual model. Average tool tip velocity and movement smoothness in the velocity frequency domain are validated parameters defining proficiency of movement. The data were filtered and interpolated to calculate the metrics. Trials containing critical tool manipulation errors were excluded.

RESULTS

In total, 52 tasks completed by novices, 25 completed by intermediates, and 38 completed by experts were analyzed to determine performance. The difference in performance between the novice and expert groups was statistically significant for guidewire smoothness (P < .001). The expert group had a statistically significantly higher average guidewire velocity compared with the novice group (P < .001).

CONCLUSIONS

The Fundamentals of Endovascular and Vascular Surgery model continues to differentiate novices from experts on the basis of their handling of guidewire and catheter tools, measured as smoothness and velocity. This model offers a useful instrument to test competency of endovascular surgeons.

Tortuosity of the descending thoracic aorta: Normal values by age

Background

Aging changes the aorta in length, tortuosity and diameter. This is relevant in thoracic endovascular aortic repair (TEVAR) and in the long term follow up.

Methods and results

Two groups of hundred patients < 65 years and hundred patients ≥ 65 years, with no vascular diseases were made. Thin cut CT scans were analyzed with 3Mensio Vascular software and the following measurements were collected; tortuosity index, curvature ratio, maximum tortuosity in degrees and the level of vertebrae of the maximum tortuosity. The descending thoracic aorta (DTA) was analyzed and was divided into four zones of equal length. Subjects were divided into three groups based on their maximum tortuosity value: low (< 30°), moderate (30° – 60°) and high (> 60°). A linear regression model was built to test the effect of age and gender on tortuosity. Tortuosity was more pronounced in the ≥ 65 compared to the < 65 group (tortuosity index: 1.05 vs. 1.14, respectively; p < 0.001), curvature ratio (1.00 vs. 1.01; p < 0.001), maximum tortuosity (22.24 vs. 27.26; p < 0.001), and group of angulation (low vs. low; p < 0.001). Additionally, the location of maximum tortuosity was further distal for the ≥ 65 group (level of vertebrae; 5.00 vs. 5.00; p < 0.001), and zone of maximum tortuosity (4A vs. 4A; p < 0.001). There was no significant difference between male and female subjects.

Conclusion

Normal DTA tortuosity increases with age. This is important to understand natural aging and for TEVAR planning and follow-up.

Identifying and addressing the limitations of EVAR technology

INTRODUCTION

Endovascular aortic repair (EVAR) has improved over the last two decades. Approximately 80% of the patients presenting with an abdominal aortic aneurysm (AAA) is nowadays primarily treated with EVAR.

AREAS COVERED

In this review, the differences between endovascular and open repair, the clinical characteristics needed for EVAR, the role of clinical imaging and the developments in EVAR technology will be discussed. Early mortality is lower in EVAR as compared to open repair, whereas this benefit is lost after 3 years postoperatively. EVAR comes with a high reintervention rate, with endoleak being the most important predictive factor for reintervention. Expanding technical possibilities have allowed surgeons to choose from a palate of endovascular approaches in aneurysm patients with challenging anatomies.

EXPERT COMMENTARY

Although EVAR has taken a giant leap forward in development, the new developments have seemed to surpass the long-term limitations with older devices. It is important to start focusing on the current limitations of EVAR, in particular the durability of devices in the human variable anatomic and dynamic environment.