How Does the Ascending Aorta Geometry Change When It Dissects?

Age-related differences in acute aortic dissection

OBJECTIVE

The present study investigated the differences in clinical characteristics, treatments, and outcomes of patients with acute aortic dissection (AAD) in different age groups.

METHODS

The present single-center retrospective study was conducted from August 2014 to August 2020. The patients were divided into three groups: age <45 years (young group), age 45 to 59 years (middle-age group), and age >59 years (elderly group). Type A (TAAD) and type B (TBAD) aortic dissection were evaluated separately using the latest definitions.

RESULTS

The mean age at onset was 52.4 years in our cohort of 602 patients. The young group included a large proportion of male patients (86%). The body mass index and body surface area were higher in the young group. The proportion of non-true lumen blood supply of branches on the abdominal aorta in the young group (27%-55%) was greater than that in the others. In the young group, the distal extent of dissection in 84% of TAAD and 89% of TBAD exceeded the abdominal aortic branch cluster (AABC) compared with 36% of TAAD and 58% of TBAD in the elderly group. The multivariate analysis revealed that age <45 years (odds ratio, 5.15; P < .001) and D-dimer level (odds ratio, 1.05; P = .001) were risk factors for intimal flap tear exceeding the AABC. The proportion of visceral and lower limb malperfusion increased from 4.8% to 36.9% as the intimal flap tear exceeded the AABC.

CONCLUSIONS

Compared with middle-age and elderly patients, young patients with AAD had two characteristics (ie, obesity and an intimal flap that had frequently exceeded the branches of the aorta). These two factors resulted in a greater proportion of non-true lumen blood supply, increased visceral and lower limb malperfusion, and an increase in potential associated risks.

Distal Aortic Remodeling after Type A Dissection Repair: An Ongoing Mirage

Remodeling is a commonly encountered term in the field of cardiothoracic surgery that is often used to describe various pathophysiological changes in the dimension, structure, and function of various cardiac chambers, including the aorta. Stanford type A or DeBakey type 1 aortic dissection (TAAD) is a perplexing pathologic condition that can present surgical teams with the need to navigate a maze of complex decision-making. Ascending or hemi-arch replacement leaves behind a significant amount of distal diseased aortic tissue, which might have a persistent false lumen or primary or secondary intimal tears (or communications between lumina), which can lead to dilatation of the aortic arch. Unfavorable aortic remodeling is a major cause of distal aortic deterioration after the index surgery. Cardiac surgeons are aware of post-surgical cardiac chamber remodeling, but the concept of distal aortic remodeling is still idealized. The contemporary literature from established aortic centers supports aggressive management of the residual aortic pathology during the index surgery, and with continuing technical advancements, endovascular stenting options are readily available for patients with TAAD or for complicated type B aortic dissection cases. This review discusses the pathophysiology and treatment options for favorable distal aortic remodeling, as well as its impact on mid- to long-term outcomes following TAAD repair.

Root Dilatation Is More Malignant Than Ascending Aortic Dilation

Background Data from the International Registry of Acute Aortic Dissection indicate that the guideline criterion of 5.5 cm for ascending aortic intervention misses many dissections occurring at smaller dimensions. Furthermore, studies of natural behavior have generally treated the aortic root and the ascending aorta as 1 unit despite embryological, anatomical, and functional differences. This study aims to disentangle the natural histories of the aforementioned aortic segments, allowing natural behavior to define specific intervention criteria for root and ascending segments of the aorta. Methods and Results Diameters of the aortic root and mid-ascending segment were measured separately. Long-term complications (dissection, rupture, and death) were analyzed retrospectively for 1162 patients with ascending thoracic aortic aneurysm. Cox regression analysis suggested that aortic root dilatation (P=0.017) is more significant in predicting adverse events than mid-ascending aortic dilatation (P=0.087). Short stature posed as a serious risk factor. The dedicated risk curves for the aortic root and the mid-ascending aorta revealed hinge points at 5.0 and 5.25 cm, respectively. Conclusions The natural histories of the aortic root and mid-ascending aorta are uniquely different. Dilation of the aortic root imparts a significant higher risk of adverse events. A diameter shift for intervention to 5.0 cm for the aortic root and to 5.25 cm for the mid-ascending aorta should be considered at expert centers.

Acute aortic dissection with entry tear at the aortic arch: long-term outcome

OBJECTIVES

The goal was to evaluate outcomes after conservative or surgical treatment of acute aortic arch dissections.

METHODS

Between January 2009 and December 2018, patients with a diagnosis of acute aortic dissection were analysed. Aortic arch aortic dissection was defined as a dissection with an isolated entry tear at the aortic arch with no involvement of the ascending aorta.

RESULTS

Aortic arch dissection was diagnosed in 31 patients (age 59 ± 11 years). Surgical intervention was performed in 13 (41.9%) cases. Overall in-hospital mortality was 3% (n = 1), and all deaths occurred in the conservative group (n = 1; 6%), whereas the overall stroke rate was 3% (n = 1), and all strokes occurred in the group treated surgically (n = 1; 8%). Surgical repair was necessary for the following conditions: end-organ malperfusion (n = 9; 69%), impending rupture (n = 3; 23%) and dilatation of the aorta with ongoing pain refractory to medical treatment (n = 1; 8%). Overall survival at the end of the follow-up period was 71%, with 77% in the surgical group and 63% in the conservative group (P = 0.91). Freedom from surgical intervention was 71%, with 82% in the surgical and 63% in the conservative group (P = 0.21), and freedom from a neurological event was 88%, with 89% versus 89% (P = 0.68) in the surgical and conservative groups, respectively.

CONCLUSIONS

Aortic arch dissection is a rare pathological condition that is one of the most challenging decision-making entities. Patients manifesting an uneventful course not requiring a surgical intervention during a hospital stay were at a higher risk for aorta-related intervention during the follow-up period. The treatment modality had no impact on survival or on the incidence of a neurological event.

Type A acute aortic dissection with ≥40-mm aortic root: results of conservative and replacement strategies at long-term follow-up

OBJECTIVES

We evaluated the long-term results of aortic root (AR) preservation and replacement in patients operated on for acute type A aortic dissection.

METHODS

Out of 302 patients discharged after repair of acute aortic dissection (1977-2019), 124 patients had an AR ≥40 mm, which was preserved in 84 (68%, group A) patients and replaced in 40 (32%, group B) patients. Group B patients were younger (mean age 57 ± 12 vs 62 ± 11 years, P = 0.07), with a mean AR of 47 vs 43 mm and ≥moderate aortic insufficiency in 65% vs 30%. Survival, causes of death and reoperations were analysed at mean follow-up of 9 ± 8 years (6 months to 40 years).

RESULTS

Actuarial survival of discharged patients at 5, 10 and 15 years was 97% (0.89-0.99), 78% (0.67-0.90) and 75% (0.64-0.88) in group A, and 85% (0.71-0.95), 62% (0.44-0.78) and 57% (0.39-0.76) in group B (log-rank test P = 0.2). Nine patients in group A (7 patients for aortic insufficiency and dilatation of the root and 2 patients for pseudoaneurysm) and 1 patient of group B (pseudoaneurysm of the right coronary button) required proximal reoperation without deaths. At 5, 10 and 15 years, the cumulative incidence of proximal aortic reoperations was 5%, 9% and 25% in group A, and 0%, 3% and 3% in group B (P = 0.02). At multivariable analysis AR >45 mm [hazard ratio (HR) 6.8, P = 0.026] and age (HR 0.9, P = 0.016) were independently associated with proximal reoperation.

CONCLUSIONS

AR preservation in acute type A dissection showed acceptable long-term outcomes. Nevertheless, a more aggressive approach appears a valid option, especially in patients with AR diameter >45 mm.

Endovascular repair of ascending aortic diseases with custom-made endografts

OBJECTIVES

The aim of this article is to report the mid-term results of ascending thoracic endovascular aortic repair using a custom-made device (CMD).

METHODS

This was a retrospective study performed at tertiary centres. Nine patients considered unfit for open surgery received elective total endovascular repair of the ascending aorta with a Relay® (Terumo Aortic, Sunrise; FL, USA) CMD: pseudoaneurysn (n = 5), localized dissection (n =3) and contained rupture (n = 1).

RESULTS

Primary clinical success was achieved in all patients with no major complications and no early conversion to open surgery. All patients were discharged home and independent: median length of stay was 7 days (interquartile range, 6-18). No patient was lost to follow-up at a median 26 months (interquartile range, 12-36). Three patients died 2, 6 and 24 months after intervention; 1 was aorta related (late aorto-atrial fistula due to infection that required open surgery). At the last follow-up available, no endoleaks, migrations, fractures or ruptures were observed in the remaining 6 patients.

CONCLUSIONS

Ascending thoracic endovascular aortic repair with Terumo Aortic CMDs was technically feasible, effective and safe in very selected lesions. CMDs showed good ascending aorta conformability with different configurations and diameters, and satisfactory mid-term durability as shown by both structural integrity and aortic lesion exclusion.

Type A aortic dissection in aneurysms having modelled pre-dissection maximum diameter below 45 mm: should we implement current guidelines to improve the survival benefit of prophylactic surgery?

OBJECTIVES

Current guidelines recommend prophylactic replacement of the ascending aorta at an aneurysmal diameter of >55 mm to prevent acute Type A aortic dissection (TAAD) in non-Marfan patients. Several publications have challenged this threshold, suggesting that surgery should be performed in smaller aneurysms to prevent this devastating disease. We reviewed our experience with measuring aortic size at the time of TAAD to validate the existing recommendation for prophylactic ascending aorta replacement.

METHODS

All patients who had been admitted for TAAD to our emergency department from 2014 to 2019 and underwent ascending aorta replacement were included. Marfan patients were excluded. The maximum diameter of the dissected aorta was measured preoperatively using CT scan. We estimated the aortic diameter at the time of dissection to be 7 mm smaller than the measured maximum diameter of the dissected aorta (modelled pre-dissection diameter).

RESULTS

Overall, 102 patients were included. Of these, 67 were male (65.6%) and 35 were female (34.4%), and the cohort’s mean age was 65 ± 12.1 years. In addition, 66% were treated for arterial hypertension. The mean maximum modelled pre-dissection diameter was 39.6 ± 4.8 mm: 39.1 ± 5.1 mm in men and 40.7 ± 2.8 mm in women (P = 0.1). The cumulative 30-day mortality rate was 19.6% (20/102).

CONCLUSIONS

TAAD occurred at a modelled aortic diameter below 45 mm in 87.7% of our patients. Therefore, the current aortic diameter threshold of 55 mm excludes ∼99% of patients with TAAD from prophylactic replacement of the ascending aorta. The maximum diameter of the ascending aorta warrants reappraisal and this parameter should be a distinct part of a personalized decision-making process that also takes into account age, gender and body surface area to establish the surgical indication for preventive aorta replacement aimed to improve the survival benefit of this procedure.

Subacute/chronic type A aortic dissection: a retrospective cohort study

OBJECTIVES

Our goal was to outline the clinical presentations, surgical treatment and outcomes of subacute/chronic type A aortic dissection (TAAD).

METHODS

A total of 1092 patients with TAAD were enrolled retrospectively and divided into 2 groups based on acuity of TAAD (181 subacute/chronic vs 911 acute cases of TAAD). Early and late outcomes were investigated and compared using propensity score matching.

RESULTS

The top 3 symptoms for subacute/chronic TAAD were chest tightness (80/181, 44.2%), mild pain (65/181, 35.9%) and sweating (58/181, 32.0). Fifteen (15/181, 8.3%) patients were symptom-free. Typical symptoms of acute TAAD were less common in patients with subacute/chronic TAAD such as intense/sharp pain (48/181, 26.5%), tear-like pain (35/181, 19.3%) and radiating pain (30/181, 16.6%). Patients with subacute/chronic TAAD had better early and late survival rates, with an early mortality rate of 6.1% (11/181) compared to 11.6% (106/911) of those with acute TAAD (P = 0.038). Before propensity score matching, survival at 1, 3 and 5 years was 93.1% [95% confidence interval (CI) 89.4-96.9%], 88.4% (95% CI 83.1-93.9%) and 86.4% (95% CI 80.1-93.1%) for subacute/chronic TAAD and 86.9% (95% CI 84.7-89.2%), 82.6% (95% CI 79.9-85.3%) and 79.0% (95% CI 75.5-82.7%) for acute TAAD, respectively (P = 0.039). The propensity score matching analysis substantiated the foregoing results.

CONCLUSIONS

Subacute/chronic TAAD was clearly distinct from acute TAAD in terms of clinical presentations and had better early and late survival rates. Current surgical strategies for acute TAAD are applicable to subacute/chronic TAAD with excellent outcomes.

Correlations between aortic tortuosity, diameter and presence of acute type A aortic dissection

BACKGROUND

Currently, only patients with ascending aorta diameter exceeding 55mm will undergo prophylactic surgery. However, diameter alone is insufficient for precise risk stratification. An International Registry of Acute Aortic Dissections study showed that nearly 60% of patients with type A aortic dissection had a diameter<55mm. This study aims to compare the tortuosity of the ascending aorta between ATAAD patients and healthy controls and evaluate correlations between aortic tortuosity/diameter and presence of ATAAD.

METHODS

A total of 75 cases in the ATAAD group and 83 cases in the Control group were enrolled. Tortuosity was calculated as the ratio of the total curve length (Lc) of the centerline to the linear distance (d) between its two endpoints, as assessed by an electronic caliper. The measurements were made on all patients by just one cardiovascular radiologist using 3-dimensional computerized tomographic imaging. ROC analysis was used to reckon the best cut-off level that prognosis occurrence of ATAAD. Correlation analysis was used to evaluate the correlation between ATAAD and tortuosity.Logistic regression was used to evaluate the relation between ATAAD and tortuosity. The tortuosity of ascending aorta was compared with a healthy control group using propensity score.

RESULTS

According to the ROC analysis, the best cut-off level that prognosis occurrence of ATAAD was 0.135. In addition, the occurrence of ATAAD showed a strong correlation with maximum diameter of the ascending aorta (r 0.587, p < 0.001), and moderate correlation with ascending aortic Tortuosity (r 0.425, p<0.001). 96 patients were matched based on propensity scores (ATAAD n=48, controls n=48). The ascending aorta was more tortuous and more dilated in ATAAD patients compared with healthy controls (0.15±0.06 vs. 0.11±0.05, p<0.001, 37.96mm±7.31 vs. 31.67mm±2.78, p<0.001, respectively).

CONCLUSIONS

Our study found that the occurrence of ATAAD showed a strong correlation with maximum diameter of the ascending aorta, and moderate correlation with ascending aortic Tortuosity. Adding tortuosity to the ATAAD prediction system will improve the ability to identify high-risk groups of ATAAD. When the tortuosity is more significant than 0.135, prophylactic surgical intervention should be considered.

Ascending Aortic Length and Its Association With Type A Aortic Dissection

Background

The aim of this study was to determine the role of ascending aortic length and diameter in type A aortic dissection.

Methods and Results

Computed tomography scans from patients with acute type A dissections (n=51), patients with proximal thoracic aortic aneurysms (n=121), and controls with normal aortas (n=200) were analyzed from aortic annulus to the innominate artery using multiplanar reconstruction. In the control group, ascending aortic length correlated with diameter (r²=0.35, P<0.001), age (r²=0.17, P<0.001), and sex (P<0.001). As a result of immediate changes in aortic morphology at the time of acute dissection, predissection lengths and diameters were estimated based on models from published literature. Ascending aortic length was longer in patients immediately following acute dissection (median, 109.7 mm; interquartile range [IQR], 101.0–115.1 mm), patients in the estimated predissection group (median, 104.2 mm; IQR, 96.0–109.3 mm), and patients in the aneurysm group (median, 107.0 mm; IQR, 99.6–118.7 mm) in comparison to controls (median, 83.2 mm; IQR, 74.5–90.7 mm) (P<0.001 all comparisons). The diameter of the ascending aorta was largest in the aneurysm group (median, 52.0 mm; IQR, 45.9–58.0 mm), followed by the dissection group (median, 50.3 mm; IQR, 46.6–57.5 mm), and not significantly different between controls and the estimated predissection group (median, 33.4 mm [IQR, 30.7–36.7 mm] versus 35.2 mm [IQR, 32.6–40.3 mm], P=0.09). After adjustment for diameter, age, and sex, the estimated predissection aortic lengths were 16 mm longer than those in the controls and 12 mm longer than in patients with nondissected thoracic aneurysms.

Conclusions

The length of the ascending aorta, after adjustment for age, sex, and aortic diameter, may be useful in discriminating patients with type A dissection from normal controls and patients with nondissected thoracic aneurysms.

3D morphometric analysis of ascending aorta as an adjunctive tool to predict type A acute aortic dissection

Background

Acute type A aortic dissection (AAAD) is a pathological process that implicates the ascending aorta and represents a surgical emergency burdened by high mortality if not promptly treated in the first hours of onset. Despite best efforts, the annual incidence rates of aortic dissection has remained stable over the past decades. We measured aortic dimensions (aortic diameters, area, length and volume) using 3D multiplanar reconstruction imaging with the purpose of refining the risk- morphology for AAAD.

Methods

Computerized tomography angiography studies of three groups were compared retrospectively: patients affected by AAAD (AAAD group; n=71), patients affected by aortic aneurysm and subsequently subjected to ascending aorta replacement (Aneurysm, n=77) and a healthy aorta’s group (Control, n=75).

Results

Mean diameters of AAAD (4.9 cm) and Aneurysm (5.1 cm) aortas were significantly larger than those of the control group (3.4 cm). In AAAD patients, an ascending aorta diameter greater than 5.5 cm was observed in 18% of patients. Multiple comparisons showed statistically significant differences among mean of the ratio of aortic root area to height between the three groups (P<0.001). In frontal and sagittal planes, the length of the ascending aorta was significantly greater in patients affected by aortic pathology (AAAD and aneurysm) than in the control group (P<0.001). Significant differences were confirmed when indexing the aortic length to patient’s height and BSA, and the aortic volume to patient’s BSA.

Conclusions

Maximum transverse diameter, considered separately, is not the best predictor of aortic dissection. In our opinion, the introduction into clinical practice of measurements of the area, length, and volume of the aorta, as absolute or indexed values, could improve the selection of patients who would benefit from preventive surgical aortic replacement.

Protocol for a randomised controlled trial for Treatment in Thoracic Aortic Aneurysm: Surgery versus Surveillance (TITAN: SvS)

INTRODUCTION

Ascending thoracic aortic aneurysm (ATAA) is an asymptomatic condition that can lead to catastrophic events of rupture or dissection. Current guidelines are based on limited retrospective data and recommend surgical intervention for ATAA with a diameter of greater or equal to 5.5 cm. Treatment in Thoracic Aortic Aneurysm: Surgery versus Surveillance is the first prospective, multicentre, randomised controlled trial that compares outcomes of patients undergoing early elective ascending aortic surgery to patients undergoing medical surveillance.

METHODS AND ANALYSIS

Patients between the ages of 18 and 80 with an asymptomatic ATAA between 5.0 cm and 5.4 cm in diameter are eligible for randomisation to early surgery or surveillance. Patients in the surgery group will be followed at 1 month after discharge, then annually for a minimum of 2 years and up to 5 years. Patients in the surveillance group will be followed annually from their index clinic visit for a minimum of 2 years and up to 5 years. The primary outcome is all-cause mortality at follow-up. A sample size of 618 subjects (309 in each group) will achieve an 80% power at a 0.047 significance level.

ETHICS AND DISSEMINATION

This study has received Ottawa Health Science Network Research Ethics Board approval (Protocol 20180007-01H), which was most recently updated on 25 November 2020. The Research Ethics Board have granted approval to the study at 14 participating institutions, including the Ottawa Health Science Network Research Ethics Board. On completion of data analysis, the result of the trial will be presented at national and international conferences, and published in relevant journals, regardless of the finding of the trial.

TRIAL REGISTRATION NUMBER

NCT03536312.

Implications of abnormal ascending aorta geometry for risk prediction of acute type A aortic dissection

OBJECTIVES

Recently, increased length of the ascending aorta has been suggested as a possible risk factor for acute type A aortic dissection (ATAAD). Our goal was to identify measurable aortic geometrical characteristics associated with elongation that could differentiate ATAAD from uncomplicated aortic dilation (>45 mm).

METHODS

In angiographic computed tomography scans performed in 180 patients having cardiac surgery, aortic diameters, root length, length of the ascending aorta at both the centreline and the greater curvature (convexity) and the root-ascending (root-asc) angle (that between the root axis and the axis of the ascending tract) and the ascending-arch (asc-arch) angle (that between the axis of the ascending aorta and the arch axis) were measured and compared among 3 patient groups: normal aorta (diameter < 45 mm), dilation/aneurysm (>45 mm) and ATAAD. Correlations between diameters and angles, diameters and lengths and lengths and angles were analysed; multivariable analysis including geometrical factors was performed to identify independent predictors of ATAAD.

RESULTS

Both patients with aneurysms and patients with ATAAD showed significantly elongated ascending aortas (P < 0.001 vs normal). However, in the aneurysms, the root-asc angle (136° ± 20° vs 147° ± 17°; P < 0.001) and in ATAAD the asc-arch angle were uniquely narrower than that in the normal aorta (116° ± 11° vs 132° ± 19°; P < 0.001). All patients with an ATAAD had an asc-arch angle ≤130°. Both in patients with ATAAD and in those without ATAAD, narrowing of the asc-arch angle was associated with elongation of the root segment (P < 0.001). In multivariable analysis, the asc-arch angle and the total length of the ascending aorta (root + tubular) were significant predictors of ATAAD.

CONCLUSIONS

The asc-arch angle is a promising measurement that could help predict aortic dissection along with aortic diameter and length: further verification is warranted.

Elective replacement of the ascending aorta: is the 5.5-cm threshold appropriate? The insidious, small aorta

OBJECTIVES

As thoracic aortic aneurysm disease continues to cause significant morbidity and mortality in the general population, the cardiovascular community continues the search for the golden threshold of elective surgical replacement of the ascending aorta.

METHODS

Thoracic aortic aneurysm is a common disease, classified within the 20 most common causes of death in patients over 65 years old. Once aortic complications like dissection or rupture occur, they can prove fatal. Prophylactic surgical replacement of the ascending aorta remains the mainstay of treatment to prevent these complications. Current American and European guidelines agree that the threshold for the diameter for elective replacement of the ascending aorta in non-syndromic, asymptomatic aneurysmal disease is 5.5 cm. Overall, aortic dissection is related to poor prognosis, thus making early intervention paramount.

RESULTS

There is a critical size above which the risk of dissection or rupture becomes extremely high. However, a significant post-dissection increase in diameter is reported, thus rendering the predissection aortic diameter well below the current threshold for elective surgical replacement of the ascending aorta. Moreover, it is widely reported that the majority of acute aortic dissections would not meet the criteria for prophylactic surgery prior to dissection. Additionally, elective surgical ascending aortic replacement in the current era shows a significantly improved risk-benefit ratio, which justifies a more aggressive approach in the management of aortic aneurysmal disease.

CONCLUSIONS

As a result, there is a lot of discussion in the literature about the requirement of a leftward shifting of the surgical threshold for elective aortic replacement.

Aortic Arch Anatomy in Candidates for Aortic Arch Repair

Detailed knowledge of aortic anatomy is necessary before new prostheses can be developed. Our aim was to provide a thorough analysis of aortic arch anatomy in patients who are potential candidates for arch repair. Patients' charts were screened between 2001 and 2019 for all those with a dissection or aneurysm involving aortic arch. Aortic diameters, segmental lengths, aortic arch type, tortuosity, diameters and length of supraaortic vessels were analyzed via computed tomography angiography. We included 558 patients who underwent thoracic aortic treatment for type A, B, non-A non-B dissection, or aortic arch aneurysm. Incidence of all three arch types was similar in patients with type A dissection. In type B dissection and arch aneurysm patients, arch type III was most commonly observed (47% and 52%, respectively). The left vertebral artery offspring from aortic arch was observed in 6.6%. The mid-ascending aorta and aortic arch were not dilated in type B and non-A non-B dissection patients. The innominate, left common carotid and left subclavian arteries median diameters were 16 (14; 18), 8 (7; 9) and 11 (10; 12) mm, respectively. The median innominate artery length was 37 (30; 44) mm. The median left subclavian artery length was 40 (34; 46) mm. Arch types are distributed differently among patients with various arch pathologies. Patients with aortic dissection type B and non-A non-B have a non-dilated ascending aorta and aortic arch. Aortic arch tortuosity, innominate and left subclavian artery lengths do not differ among aortic pathologies.

Diameter change in completely remodelled proximal descending aorta after acute type I dissection repair: implications for estimating the pre-dissection size

 

OBJECTIVES

Pre-dissection diameter of the proximal descending thoracic aorta (p-DTA), if available, would be the reference for determining the size of the stent graft or elephant trunk. Acute type B dissection is known to increase p-DTA diameter by 23% (Rylski factor). This study aimed to investigate the accuracy of estimating post-remodelling diameter of the p-DTA based on the Rylski factor and other post-dissection morphological parameters in acute type I dissection, based on the assumption that the post-remodelling diameter is similar to the pre-dissection diameter.

METHODS

In 60 patients with acute type I dissection showing complete remodelling of the p-DTA false lumen after surgical repair, preoperative and post-remodelling computed tomography scans were reviewed. Parameters, including maximal true lumen diameter (TLDmax) and aortic area-derived diameter divided by the Rylski factor (AoDRylski), were measured at the p-DTA.

RESULTS

After complete remodelling, p-DTA diameter decreased by 4.1 mm (P < 0.001). The equivalent to the Rylski factor was 15%. Both TLDmax and AoDRylski frequently showed ≥2 mm discrepancy from post-remodelling aortic diameter (36.7% and 48.3%, respectively, P = 0.30). When 2 parameters coincided within 2 mm, two-third of their estimations were accurate. AoDRylski was more accurate than TLDmax in patients with a large extent of circumferential dissection, and vice versa with less circumferential dissection (P = 0.027).

CONCLUSIONS

Prediction of post-remodelling aortic diameter relying on a single morphologic parameter carries a substantial risk of overestimation and underestimation. Evaluation based on the extent of circumferential dissection together with the 2 parameters may provide a more reliable estimation.

Quantitative magnetic resonance imaging measures of three-dimensional aortic morphology in healthy aging and hypertension

Automated segmentation of three-dimensional (3D) aortic magnetic resonance imaging (MRI) renders a possible retrospective selection of any location to perform quantification of aortic caliber perpendicular to its centerline and provides regional and global 3D biomarkers such as length, diameter, or volume. However, normative age-related values of such measures are still lacking. The aim of this study was to provide normal values for 3D aortic morphological measures and investigate their changes in aging and hypertension. This was a retrospective study, in which 119 healthy controls (HC: 48 ± 14 years, 61 men) and 82 hypertensive patients (HT: 60 ± 14 years, 43 men) were enrolled. 1.5 and 3 T/3D steady state free precession or spoiled gradient echo were used. Automated 3D aortic segmentation provided aortic length, diameter, volume for the ascending (AAo), and descending aorta (DAo), along with cross-sectional diameters at three aortic landmarks. Age, sex, body surface area (BSA), smoking, and blood pressures were recorded. Both groups were divided into two subgroups (≤50 years, >50 years). Statistical tests performed were linear regression for age-related normal values and confidence intervals, Wilcoxon rank sum test for differences between groups (HC or HT), and multivariate analysis to identify main determinants of aortic morphological changes. In HC, linear regression revealed an increase in the AAo (respectively DAo) length by 2.84 mm (7.78 mm), maximal diameter by 1.36 mm (1.29 mm), and volume by 4.28 ml (8.71 ml) per decade. AAo morphological measures were higher in HT patients than in HC both ≤50 years but did not reach statistical significance (length: +2 mm, p = 0.531; diameter: +1.4 mm, p = 0.2936; volume:+6.8 ml, p = 0.1857). However, length (+6 mm, p = 0.003), maximal diameter (+4 mm, p < 0.001) and volume (+12 ml, p < 0.001) were significantly higher in HT patients than in HC, both >50 years. In a multivariate analysis, age, sex, and BSA were the major determinants of aortic morphology, irrespective of the presence of hypertension. Global and segmental aortic length, volume, and diameters at specific landmarks were automatically measured from 3D MRI to serve as normative measures of 3D aortic morphology. Such indices increased significantly with age and hypertension among the elderly subjects. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 3.

Systolic stretching of the ascending aorta

INTRODUCTION

Longitudinal stretching of the aorta due to systolic heart motion contributes to the stress in the wall of the ascending aorta. The objective of this study was to assess longitudinal systolic stretching of the aorta and its correlation with the diameters of the ascending aorta and the aortic root.

MATERIAL AND METHODS

Aortographies of 122 patients were analyzed. The longitudinal systolic stretching of the aorta caused by the contraction of the heart during systole and the maximum dimensions of the aortic root and ascending aorta were measured in all patients.

RESULTS

The maximum dimension of the aortic root was on average 34.9 ±4.5 mm and the mean diameter of the ascending aorta was 33.9 ±5.4 mm. The systolic aortic stretching negatively correlated with age (r = -0.49, p < 0.001) and the diameter of the tubular ascending aorta (r = -0.44, p < 0.001). There was no significant correlation between the stretching and the dimension of the aortic root (r = -0.11, p = 0.239). There was a statistically significant (p < 0.001) difference in the longitudinal aortic stretching values between patients with a normal aortic valve (10.6 ±3.1 mm) and an aortic valve pathology (8.0 ±3.2 mm in all patients with an aortic valve pathology; 7.5 ±4.3 mm in isolated aortic stenosis, 8.5 ±2.9 mm in the case of isolated insufficiency, 8.2 ±2.8 mm for valves that were both stenotic and insufficient).

CONCLUSIONS

Systolic aortic stretching negatively correlates with the diameter of the tubular ascending aorta and the age of the patients, and does not correlate with the diameter of the aortic root. It is lower in patients with an aortic valve pathology.

New indicators for systematic assessment of aortic morphology: a narrative review

In order to prevent the occurrence of aortic adverse events in ascending thoracic aortic aneurysm patients, preventive surgery is the sole option in case of large aneurysm. Identifying high-risk patients timely and accurately requires effective predictive indicators of aortic adverse events and accurate risk stratification thresholds. Absolute diameter measured after a single imaging examination, which has been used as the predictive indicator for decades, has been proved to be ineffective for risk stratification in moderately dilated aorta. Previously, new indicators combining absolute diameters with personalized parameters have been reported to show better predictive power of aortic adverse events than absolute diameters by correcting the effect of these parameters on the diameters. Meanwhile, combining three-dimensional parameters to formulate risk stratification thresholds not only may characterize the aortic risk morphology more precisely, but also predict aortic adverse events more accurately. These new indicators may provide more systematic assessment methods of patients’ risk, formulate more personalized intervention strategies for ascending thoracic aortic aneurysm patients, and also provide a basis for researchers to develop more accurate and effective risk thresholds. We also highlight that the algorithm obtained by combining multiple indicators may be a better choice compared with single indicator, but this still requires the support of more evidence. Due to the particularity of syndromic aortic disease, whether these new indicators can be used for its risk stratification is still uncertain. Therefore, the scope of this manuscript does not include this kind of disease.

Ascending Aortic Diameter after Dissection Does Not Reflect Size before Dissection

Introduction

Current guidelines for prophylactic resection of ascending aortic aneurysms are based on post-dissection aortic diameter. However, this may not reflect the diameter prior to dissection.

Report

Pre- and post-dissection aortic diameters were compared in 34 patients with available computerised tomography scans. The median time interval between these scans was 536 days (interquartile range 354 – 1237).

Discussion

There was a statistically significant difference in diameters from the sinotubular junction to the proximal abdominal aorta, the largest was in the ascending aorta with a mean of 7.6 mm (standard deviation 4.5). This suggests that the ascending aortic diameter is a poor predictor of dissection in most patients.

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Ascending aortic diameter expands due to acute dissection.

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Post-dissection aortic diameters probably overestimate pre-dissection diameters.

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Following ascending dissection, diameter expansion is not limited to aorta ascendens.

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In this sample, estimated pre-dissection ascending aortic diameters were below 60 mm in 91% of patients and below 50 mm in 85%.

Are dilated ascending aortas of Chinese patients more likely to dissect?

Background

Ascending aortic aneurysm is a disease requiring surgical intervention. However, the timing of operation is still controversial. The purpose of this study is to compare the ascending aortic diameter and postoperative outcomes in hospital between patients with simple ascending aortic dissection and patients with simple ascending aortic dilation in China, and to investigate the accuracy of the timing of operation determined by ascending aortic diameter alone.

Methods

We reviewed the data from 2,520 hospitalized patients of aortic aneurysm and aortic dissection who underwent surgical treatment from January 2010 to June 2017 in our hospital. A total of 139 simple ascending aortic dissection and simple ascending aortic aneurysm hospitalized patients excluding Marfan syndrome and heart valve diseases etc. (56 in the aortic dilatation group and 83 in the aortic dissection group) were enrolled. The t-test and univariable analysis were used to compare the differences between two groups.

Results

For the aortic diameter, the group of aneurysm has greater ascending aortic diameter and the index of ascending aortic diameter compared with the group of dissection (P<0.001, P<0.001). For male patients, the result is the same (P<0.001, P<0.001). But for female patients, there was no significant statistical significance between the two groups (P=0.631, P=0.288). For the postoperative outcomes, the dissection group had higher mortality, incidence of tracheotomy and postoperative re-exploration for hemorrhage (P=0.040, P=0.011, P=0.028).

Conclusions

The majority of patients with simple ascending aortic dissection present with aortic diameters <5.5 cm and this is not consistent with the current operation indications of aortic aneurysm. It is far from enough to predict aortic dissection with aortic diameter alone. More indicators are needed to do this.

Cardiovascular Hoarseness (Ortner's Syndrome): A Pictorial Review

Ortner's syndrome, also known as cardiovocal syndrome, encompasses any cardiac or vascular process that affects the recurrent laryngeal nerve(s), subsequently leading to vocal cord palsy. Various causes of Ortner's syndrome have been described in the literature, which include but are not limited to aortic aneurysms, pulmonary hypertension, left atrial enlargement, and congenital cardiac disorders. We hereby present a pictorial review of the more commonly reported entities, which have been implicated in this syndrome. Ultimately, understanding the pathophysiology underlying Ortner's syndrome will help in diagnosis and institution of potentially life-saving treatment.

Incidence and characteristics of hospitalization for proximal aortic surgery for acute syndromes and for aneurysms in the USA from 2005 to 2014

OBJECTIVES

The effectiveness of proximal thoracic aortic aneurysm (TAA) surgery in preventing acute aortic syndromes, such as dissection and rupture, is unknown at the populational level. This study evaluated trends in acute aortic syndrome operation incidence relative to proximal aortic surgical volume in the USA.

METHODS

A retrospective analysis of the National Inpatient Sample in 2005-2014 was performed. Acute aortic syndrome and TAA were identified with International Classification of Diseases, 9th edition diagnosis codes. Proximal aortic surgery was defined as the diagnosis of acute aortic syndrome or TAA with an aortic procedure and either cardioplegia, cardiopulmonary bypass or other cardiac operation. Annual rates of acute aortic syndrome surgery and proximal thoracic aneurysm surgery were adjusted for US population. Trends were evaluated using linear regression.

RESULTS

We identified 38 442 operations for acute aortic diagnoses and 74 953 operations for TAAs. Case volume for acute aortic syndromes increased from 0.93 to 1.63 per 100 000 (P = 0.001), and aneurysm surgery increased from 1.75 to 3.19 per 100 000 (P < 0.001). Patient and hospital characteristics differed between acute aortic and aneurysm operations, with black patients being most notably underrepresented in the aneurysm population (4.9% vs 17.0%, P < 0.001).

CONCLUSIONS

Acute aortic syndrome operative volume increased from 2005 to 2014 despite increasing rates of proximal aortic aneurysm surgery. Patient characteristic discrepancies were observed between the 2 groups of hospitalizations, highlighting the need for continued efforts to minimize sociodemographic disparities.

The role of the angle of the ascending aortic curvature on the development of type A aortic dissection: ascending aortic angulation and dissection

OBJECTIVES

Type A aortic dissection (TAD), which consists of an intimal tear in the aorta, necessitates emergency surgery. Various risk factors related to aortic dissection have been defined in the literature. According to our hypothesis, a narrower angle of ascending aortic curvature (AAAC) may be an additional risk factor in relation to aortic dissection due to the increased force applied to the aortic wall.

METHODS

Patients undergoing ascending aortic surgery due to an ascending aortic aneurysm (AsAA) (n = 105) and patients undergoing such surgery because of the occurrence of TAD (n = 101) were enrolled in this study. The AAAC was measured using Cobb's method; the measurements were made on all patients by just 1 cardiovascular radiologist using 3-dimensional computerized tomographic imaging. This measurement was made indirectly by using the aortic valve and brachiocephalic artery to avoid obtaining misleading data as a result of distortions due to dissection. A statistical comparison was also performed relating the traditional risk factors for TAD to other clinical and echocardiographic parameters: the diameter of the ascending aorta and the AAAC.

RESULTS

The AAAC was found to be narrower statistically in the TAD group (α = 76.2° ± 17.5°) than it was in the AsAA group (α = 92.9° ± 13°) (P < 0.001). Furthermore, mean ascending aortic diameter (P = 0.019), the presence of a bicuspid aorta (P = 0.007) and aortic valve stenosis (P = 0.005) were higher in the AsAA group. According to multivariable analyses, a narrower AAAC is a significant predictor for the development of TAD (odds ratio 0.93, 95% confidence interval 0.91-0.95; P < 0.001). Overall hospital mortality from various causes including stroke, myocardial infarction, bleeding or renal failure was 13% in the TAD group and 7% in the AsAA group.

CONCLUSIONS

According to this study, the AAAC was significantly smaller in aortic dissection patients than in aortic aneurysm patients. This may be related to higher shear stress and elevated pressure on the ascending aorta in patients with a narrower AAAC. Thus, a narrower AAAC may be an additional risk factor in the development of TAD. Therefore, we may need to be more careful in terms of looking for the development of aortic dissection in patients with narrower AAAC.

Evaluating the diagnostic accuracy of maximal aortic diameter, length and volume for prediction of aortic dissection

OBJECTIVE

Management of thoracic aortic aneurysms (TAAs) comprises regular diameter follow-up until the indication criterion for prophylactic surgery is reached. However, this approach is unable to predict the majority of acute type A aortic dissections (ATAADs). The current study aims to evaluate the diagnostic accuracy of ascending aortic diameter, length and volume for occurrence of ATAAD.

METHODS

This two-centre observational cohort study retrospectively screened 477 consecutive patients who presented with ATAAD between 2009 and 2018. Of those, 25 (5.2%) underwent CT angiography (CTA) within 2 years before dissection onset. Aortic diameter, length and volume of these patients ('pre-ATAAD') were compared with those of TAA controls (n=75). Receiver operating curve analysis was performed to evaluate the predictive accuracy of the three different measurements.

RESULTS

96% of patients with pre-ATAAD did not meet the surgical diameter threshold of 55 mm before dissection onset. Maximal aortic diameters (45 (40-49) mm vs 46 (44-49) mm, p=0.075) and volume (126 (95-157) cm³ vs 124 (102-136) cm³, p=0.909) were comparable between patients with pre-ATAAD and TAA controls. Conversely, ascending aortic length (84±9 mm vs 90±16 mm, p=0.031) was significantly larger in patients with pre-ATAAD. All three parameters had an area under the curve of >0.800. At the 55 mm cut-off point, the maximal diameter yielded a positive predictive value (PPV) of 20%. While maintaining same specificity levels, measurements of aortic volume and length showed superior diagnostic accuracy (PPV 55% and 70%, respectively).

CONCLUSION

Measurements of aortic volume and length have superior diagnostic accuracy compared with the maximal diameter and could improve the timely identification of patients at risk for ATAAD.

Critical appraisal of multidimensional CT measurements following acute open repair of type A aortic dissection

INTRODUCTION

To identify patients with aneurysmal degeneration of the native aorta following type A aortic dissection (TAAD), reproducible serial measurements of aortic dimensions are critical. We used a systematic workflow for measuring aortic geometry following TAAD, using computed tomography angiography data, and test its reproducibility.

METHODS

The workflow for aortic measurements included centerline generation, luminal diameter, and area measurement at six anatomically defined locations along the aorta and luminal volumetric measurements in the descending aorta. Two independent observers measured the aortic geometry in 20 surgically repaired TAAD patients, preoperatively and at 3 months follow-up. To test reproducibility, intraobserver and interobserver agreement scores were analyzed using a concordance correlation coefficient (CCC).

RESULTS

The interobserver agreement scores of the diameter, area, and volumetric measurements in the descending aorta were acceptable. The agreement scores of the area measurements were highest, with CCCs ranging from 0.909 to 0.984. Luminal diameter measurements scored lower than luminal area measurements and were least reproducible at the mid aortic arch (CCC < 0.886). Overall, intraobserver agreement scores were better than interobserver agreement scores (SD of mean difference was 1.89 vs 1.94 for intraobserver vs interobserver diameter measurements, and 0.61 vs 0.66 for area measurements).

CONCLUSION

Although overall reproducibility was acceptable in descending aortic measurements, our results show that it remains challenging to reliably measure luminal diameters, compared with areas. To aid identification of early adverse remodeling following acute TAAD, novel two- and three-dimensional measurement techniques are needed that capture locoregional changes in the false lumen and true lumen morphology more accurately.

The future of stenting in patients with type A aortic dissection: a systematic review

Acute type A aortic dissection (ATAAD) carries high morbidity and mortality rates and is a clinical emergency. The reported mortality rate is 50% to 65% within the first 48 hours without surgical intervention. Open surgery therefore remains the gold standard management for ATAAD. However, in patients who are deemed unfit for surgery and where possible, endovascular repair offers a useful alternative to medical treatment alone or high-risk open surgical repair. Several case reports, case series, and retrospective studies have reported good outcomes following endovascular treatment. The endovascular option also has comparable early and late outcomes, favourable aortic remodelling, and satisfactory overall survival despite having a higher-risk patient cohort. However, stenting in patients with ATAAD undoubtedly still has several limitations and technical challenges.

Natural history of descending thoracic and thoracoabdominal aortic aneurysms

OBJECTIVES

Elucidating critical aortic diameters at which natural complications (rupture, dissection, and death) occur is of paramount importance to guide timely surgical intervention. Natural history knowledge for descending thoracic and thoracoabdominal aortic aneurysms is sparse. Our small early studies recommended repairing descending thoracic and thoracoabdominal aortic aneurysms before a critical diameter of 7.0 cm. We focus exclusively on a large number of descending thoracic and thoracoabdominal aortic aneurysms followed over time, enabling a more detailed analysis with greater granularity across aortic sizes.

METHODS

Aortic diameters and long-term complications of 907 patients with descending thoracic and thoracoabdominal aortic aneurysms were reviewed. Growth rates (instrumental variables approach), yearly complication rates, 5-year event-free survival (Kaplan-Meier), and risk of complications as a function of aortic height index (aortic diameter [centimeters]/height [meters]) (competing-risks regression) were calculated.

RESULTS

Estimated mean growth rate of descending thoracic and thoracoabdominal aortic aneurysms was 0.19 cm/year, increasing with increasing aortic size. Median size at acute type B dissection was 4.1 cm. Some 80% of dissections occurred below 5 cm, whereas 93% of ruptures occurred above 5 cm. Descending thoracic and thoracoabdominal aortic aneurysm diameter 6 cm or greater was associated with a 19% yearly rate of rupture, dissection, or death. Five-year complication-free survival progressively decreased with increasing aortic height index. Hazard of complications showed a 6-fold increase at an aortic height index of 4.2 or greater compared with an aortic height index of 3.0 to 3.5 (P < .05). The probability of fatal complications (aortic rupture or death) increased sharply at 2 hinge points: 6.0 and 6.5 cm.

CONCLUSIONS

Acute type B dissections occur frequently at small aortic sizes; thus, prophylactic size-based surgery may not afford a means for dissection protection. However, fatal complications increase dramatically at 6.0 cm, suggesting that preemptive intervention before that criterion can save lives.

Aortic root and ascending aorta dimensions in acute aortic dissection

Objectives:

Aim of this study was to evaluate ascending aorta and aortic root dimension at acute type A dissection (acute aortic dissection) and to identify demographics elements being allied to the acute event.

Methods:

In a period between 2009 and 2017, 225 (n = 71, 32% female, mean age = 63 ± 12 years) patients eligible for analysis of ascending aorta and 223 (n = 70, 31% female, mean age = 63 ± 13 years) of aortic root were included in this study. Aortic diameter was assessed in preoperative computed tomography scan. The predissection diameters were modeled from the diameters obtained at diagnosis, assuming 30% augmentation of the diameter at acute event.

Results:

The mean diameter of the ascending aorta at dissection was 46 ± 8 mm and the modeled diameter was 32.3 ± 5.7 mm. The diameter of the aortic root at dissection was 42 ± 8 mm and modeled diameter was 29.5 ± 5.6 mm. In multivariate analysis, female gender (p = 0.026) and history of cerebrovascular event (p = 0.001) were associated with acute aortic dissection in small aortic root. Patient age (p < 0.001) and history of inguinal hernia (p = 0.001) in ascending aorta <55 mm correlated with acute aortic dissection.

Conclusion:

Modeling indicates that more than 90% of patients had aortic root and ascending aorta diameter <45 mm. It seems that the aortic diameter expansion over the 55 mm in development of acute aortic dissection is overestimated. Parameters other than aortic size were identified, which may be considered when patients at high risk for dissection were identified.

Predictive imaging for thoracic aortic dissection and rupture: moving beyond diameters

Abstract

Acute aortic syndromes comprise a group of potentially fatal conditions that result from weakening of the aortic vessel wall. Pre-emptive surgical intervention is currently reserved for patients with severe aortic dilatation, although abundant evidence describes the occurrence of dissection and rupture in aortas with diameters below surgical thresholds. Modern imaging techniques (such as hybrid PET-CT and 4D flow MRI) afford the non-invasive assessment of anatomic, hemodynamic, and molecular features of the aorta, and may provide for a more accurate selection of patients who will benefit from preventative surgical intervention. In the current review, we summarize evidence and considerations regarding predictive aortic imaging and highlight evolving imaging modalities that have shown promise to improve risk assessment for the occurrence of dissection and rupture.

Key Points

• Guidelines for the preventative management of aortic disease depend on maximal vessel diameters, while these have shown to be poor predictors for the occurrence of catastrophic acute aortic events.

• Evolving imaging modalities (such as 4D flow MRI and hybrid PET-CT) afford a more comprehensive insight into anatomic, hemodynamic, and molecular features of the aorta and have shown promise to detect vessel wall instability at an early stage.

Risk Stratification in Bicuspid Aortic Valve Aortopathy: Emerging Evidence and Future Perspectives

The current management of aortic dilatation associated with congenital bicuspid aortic valve (bicuspid aortic valve aortopathy) is based on dimensional parameters (diameter of the aneurysm, growth of the diameter over time) and few other criteria. The disease is however heterogeneous in terms of natural and clinical history and risk of acute complications, ie aortic dissection. Dimensional criteria are now admitted to have limited value as predictors of such complications. Thus, novel principles for risk stratification have been recently investigated, including phenotypic criteria, flow-related metrics, and circulating biomarkers. A systematization of the typical anatomoclinical forms that the aortopathy can assume has led to the identification of the more severe root phenotype, associated with higher risk of progression of the aneurysm and possible higher aortic dissection risk. Four-dimensional-flow magnetic resonance imaging studies are searching for potentially clinically significant metrics of flow derangement, based on the recognized association of local abnormal shear stress with wall pathology. Other research initiatives are addressing the question whether circulating molecules could predict the presence or, more importantly, the future development of aortopathy. The present review summarizes the latest progresses in the knowledge on risk stratification of bicuspid aortic valve aortopathy, focusing on critical aspects and debated points.

Aortic elongation in aortic aneurysm and dissection: the Tübingen Aortic Pathoanatomy (TAIPAN) project

OBJECTIVES

To study the lengths and diameters of aortic segments in healthy and diseased aortas and to assess the role of aortic elongation in Type A aortic dissection (TAD) prediction.

METHODS

Ectasia and aneurysm were defined by ascending aorta diameters of 45-54 mm and ≥55 mm, respectively. Computed tomography angiography studies of 256 healthy, 102 ectasia, 38 aneurysm, 17 pre-TAD and 166 TAD aortas were analysed using curved multiplanar reformats.

RESULTS

The study groups were structurally equal. The diameter of the ascending aorta was 35 mm in the control group and was larger (P < 0.001) in the pre-TAD (43 mm) and TAD (56 mm) groups. The length of the ascending aorta from the aortic annulus to the brachiocephalic trunk was 92 mm in the control group, 113 mm in the ectasia group, 120 mm in the aneurysm group and 111 mm and 118 mm in the pre-TAD and TAD groups (all P < 0.001 compared with the control group). An ascending aorta length of 120 mm was exceeded in 2% of the control group, 31% of the ectasia group, 50% of the aneurysm group, 24% of the pre-TAD group and 48% of the TAD group. The correlation between the diameter and the length of the ascending aorta was r = 0.752; therefore, both parameters must be examined separately. A score considering both parameters identified 23.5% of pre-TAD patients, significantly more than the diameter alone, and 31.4% of ectasia aortas were elongated.

CONCLUSIONS

Patients with ectatic (45-54 mm diameter) and elongated (≥120 mm) ascending aortas represent a high-risk subpopulation for TAD.

Certain aortic geometries and hemodynamics are associated with FID development and impact the evolution of uncomplicated type B intramural hematoma during the acute phase

OBJECTIVES

It is difficult to predict the evolution of uncomplicated type B intramural hematoma (IMHB) with a focal intimal disruption (FID) in the acute phase. The aims of this study were to investigate the predictors of FIDs and summarize the risk factors for the evolution of uncomplicated IMHB in the acute phase.

METHODS

Eighty-six patients with uncomplicated IMHB were included and were divided according to the development of an FID during the acute phase: the FID group (n = 32) and the no-FID group (n = 54). Geometric measurements and computed fluid dynamic calculations were based on a computed tomography scan performed on admission. Multivariate logistic regression analysis was used to estimate the predictors of FID development.

RESULTS

Thirty-two (37%) patients developed an FID. Patients with an FID had higher C-reactive protein levels (18.6 ± 2.3 vs 8.1 ± 0.2 mg/dL, P < 0.001) and white blood cell counts (10.3 ± 2.1 vs 7.5 ± 1.7 10⁹ /L, P < 0.001). The no-FID group had lower occurrences of disease progression (15% vs 64%, P < 0.001) and aorta-related mortality (6% vs 25%, P = 0.016). Multivariate logistic regression analysis indicated a significant risk for the occurrence of an FID with a larger maximum aortic diameter (OR, 1.35; 95% CI, 1.05-1.73, P = 0.020), thicker hematoma (OR, 2.20; 95% CI, 1.40-3.48, P = 0.001), and higher oscillatory shear index (per 0.01 unit, OR, 1.74; 95% CI, 1.21-2.49, P = 0.003). The aorta-related mortality during the acute phase was 25% (n = 8).

CONCLUSIONS

Certain aortic conditions, including ta larger aortic diameter, thicker hematoma and higher oscillatory shear stress, are associated with the FID development and result in worse clinical outcomes.

Equations Estimating the Predissected Diameter of the Ascending Aorta for Acute Type A Aortic Dissection

BACKGROUND

A successful endovascular treatment for acute type A dissection has been recently reported. However, there has been no consensus regarding the appropriate stent graft size based on the estimated predissected aortic diameter for this pathology.

METHODS

We developed new equations for estimating the predissected ascending aorta and aortic arch by investigating computed tomography images that had been scanned less than 3 years before dissection. From 684 patients with type A AAD, 28 were matched for the study. We measured the predissected whole circumference length (pre-wCL), postdissected whole circumference length (post-wCL), postdissected true lumen circumference length (post-tCL), postdissected major diameter (post-Dma), and postdissected minor diameter (post-Dmi) of the acutely dissected aorta. This was followed by the calculation of (post-tCL + post-wCL)/2 and (post-Dma + post-Dmi)/2. Six equations (linear function) and modified equations were derived from each of the abovementioned parameters.

RESULTS

Four equations (post-wCL, post-Dma, [post-tCL + post-wCL]/2, and [post-Dma + post-Dmi]/2) had nearly the same bias and accuracy (<9.42 mm). For clinical use, we also developed one modified equation using the post-wCL (y = 0.9x) among four parameters because of its simplicity and decreased the possibility of measurement error. The biases of circumference length and accuracy were 5.5 ± 4.9 mm and 84.6%, respectively, and they improved to 4.4 ± 3.3 mm and 93.4% in cases with a ratio of post-tCL/post-wCL of 0.66 or more.

CONCLUSIONS

Our newly developed equation can be used to calculate the predissected ascending aortic diameter and aortic arch diameter in cases of acute type A dissection.