What is the appropriate size criterion for resection of thoracic aortic aneurysms?

Morphological features of the thoracic aorta and supra-aortic branches in patients with acute Type A aortic dissection in China

OBJECTIVES

This study aimed to investigate the morphological characteristics of the dissected thoracic aorta and brachiocephalic arteries within the Chinese population.

METHODS

A retrospective analysis of computed tomography scans of 387 patients with acute Type A aortic dissection was carried out. The dimensions of the thoracic aorta at multiple levels and other imaging characteristics were studied.

RESULTS

The patients with a maximum diameter ≥55 mm accounted for less than one-third of the population. Among those without Marfan syndrome (MFS) (n = 349), only 114 (32.8%) patients had a maximal aortic diameter ≥ 55 mm, whereas among those with MFS (n = 38), 20 (78.9%) had a maximal aortic diameter ≥ 45 mm. The predicted maximum aortic diameter is 88.46 - 0.81 × height (cm) + 63.02 × body surface area (m2) + 5.50 × (if diabetes, 1, if not, 0) - 6.63 × (if hypertension, 1, if not, 0). A positive correlation was established between a circular false lumen and the probability that brachiocephalic arteries were involved by dissection. The size ratio of false lumen to true lumen was greater in the circumferential group when compared with the crescent group. The independent predictors for the circumferential false lumen were age, atherosclerosis and smoking.

CONCLUSIONS

Herein, the morphological characteristics of the thoracic aorta among Chinese patients with acute Type A aortic dissection were described. The currently recommended criteria for prophylactic aorta surgery were applied to most patients with MFS but not to those without MFS within the Chinese population. Furthermore, the shape of the false lumen was identified as a putative risk factor that might affect the prognosis of the patients.

Age-related changes of shape and flow dynamics in healthy adult aortas: A 4D flow MRI study

BACKGROUND

Abnormal flow dynamics play an early and causative role in pathologic changes of the ascending aorta.

PURPOSE

To identify: 1) the changes in flow, shape, and size that occur in the ascending aorta with normal human ageing and 2) the influence of these factors on aortic flow dynamics.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 247 subjects (age range 19-86 years, mean 49 ± 17.7, 169 males) free of aortic or aortic valve pathology were included in this study. Subjects were stratified by youngest (18-33 years; n = 64), highest (>60 years, n = 67), and the middle two quartiles (34-60 years, n = 116).

FIELD STRENGTH/SEQUENCE

Subjects underwent a cardiac MRI (3T) exam including 4D-flow MRI of the aorta.

ASSESSMENT

Aortic curvature, arch shape, ascending aortic angle, ascending aortic diameter, and the stroke volume normalized by the aortic volume (nSV) were measured. Velocity, vorticity, and helicity were quantified across the thoracic aorta.

STATISTICAL TESTS

Univariate and multivariate regressions were used to quantify continuous relationships between variables.

RESULTS

Aortic diameter, ascending aortic angle, shape, and curvature all increased across age while nSV decreased (all P < 0.0001). Systolic vorticity in the mid arch decreased by 50% across the age range (P < 0.0001), while peak helicity decreased by 80% (P < 0.0001). Curvature tightly governs optimal flow in the youngest quartile, with an effect size 1.5 to 4 times larger than other parameters in the descending aorta, but had a minimal influence with advancing age. In the upper quartile of age, flow dynamics were almost completely determined by nSV, exerting an effect size on velocity and vorticity >10 times that of diameter and other shape factors.

DATA CONCLUSION

Aortic shape influences flow dynamics in younger subjects. Flow conditions become increasingly disturbed with advancing age, and in these conditions nSV has a more dominant effect on flow patterns than shape factors.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:90-100.

Association of Mortality and Acute Aortic Events With Ascending Aortic Aneurysm: A Systematic Review and Meta-analysis

IMPORTANCE

The natural history of ascending aortic aneurysm (AsAA) is currently not well characterized.

OBJECTIVE

To summarize and analyze existing literature on the natural history of AsAA.

DATA SOURCES

A search of Ovid MEDLINE (January 1, 1946, to May 31, 2017) and Embase (January 1, 1974, to May 31, 2017) was conducted.

STUDY SELECTION

Studies including patients with AsAA were considered for inclusion; studies were excluded if they considered AsAA, arch, and descending thoracic aneurysm as 1 entity or only included descending aneurysms, patients with heritable or genetic-related aneurysms, patients with replaced bicuspid aortic valves, patients with acute aortic syndrome, or those with mean age less than 16 years. Two independent reviewers identified 20 studies from 7198 unique studies screened.

DATA EXTRACTION AND SYNTHESIS

Data extraction was performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline; 2 reviewers independently extracted the relevant data. Summary effect measures of the primary outcomes were obtained by logarithmically pooling the data with an inverse variance-weighted random-effects model. Metaregression was performed to assess the relationship between initial aneurysm size, etiology, and the primary outcomes.

MAIN OUTCOMES AND MEASURES

The primary composite outcome was incidence of all-cause mortality, aortic dissection, and aortic rupture. Secondary outcomes were growth rate, incidence of proximal aortic dissection or rupture, elective ascending aortic repair, and all-cause mortality.

RESULTS

Twenty studies consisting of 8800 patients (mean [SD] age, 57.75 [9.47] years; 6653 [75.6%] male) with a total follow-up time of 31 823 patient-years were included. The mean AsAA size at enrollment was 42.6 mm (range, 35.5-56.0 mm). The combined effect estimate of annual aneurysm growth rate was 0.61 mm/y (95% CI, 0.23-0.99 mm/y). The pooled incidence of elective aortic surgery was 13.82% (95% CI, 6.45%-21.41%) over a median (interquartile range) follow-up of 4.2 (2.9-15.0) years. The linearized mortality rate was 1.99% per patient-year (95% CI, 0.83%-3.15% per patient-year), and the linearized rate of the composite outcome of all-cause mortality, aortic dissection, and aortic rupture was 2.16% per patient-year (95% CI, 0.79%-3.55% per patient year). There was no significant relationship between year of study completion and the initial aneurysm size and primary outcomes.

CONCLUSIONS AND RELEVANCE

The growth rate of AsAA is slow and has implications for the interval of imaging follow-up. The data on the risk of dissection, rupture, and death of ascending aortic aneurysm are limited. A randomized clinical trial may be required to understand the benefit of surgical intervention compared with surveillance for patients with moderately dilated ascending aorta.

Aortic valve-mediated wall shear stress is heterogeneous and predicts regional aortic elastic fiber thinning in bicuspid aortic valve-associated aortopathy

OBJECTIVES

The objectives of this study were to investigate an association between the magnitude of flow-mediated aortic wall shear stress (WSS) and medial wall histopathology in patients with bicuspid aortic valve (BAV) with aortopathy.

METHODS

Patients with BAV (n = 27; 52 ± 15 years; 3 women; proximal thoracic aorta diameter = 4.4 ± 0.7 and 4.6 ± 0.5 cm) who underwent prophylactic aortic resection received preoperative 3-dimensional time-resolved phase-contrast magnetic resonance imaging with 3-dimensional velocity encoding to quantify WSS relative to a population of healthy age- and sex-matched tricuspid aortic valve control participants (n = 20). Quantitative histopathology was conducted on BAV aorta tissue samples resected at surgery (n = 93), and correlation was performed between elastic fiber thickness and in vivo aortic WSS as continuous variables. Validation of elastic fiber thickness was achieved by correlation relative to tissue stiffness determined using biaxial biomechanical testing (n = 22 samples).

RESULTS

Elastic fibers were thinner and WSS was higher along the greater curvature compared with other circumferential regions (vs anterior wall: P = .003 and P = .0001, respectively; lesser curvature: both P = .001). Increased regional WSS was associated with decreased elastic fiber thickness (r = -0.25; P = .02). Patient stratification with subanalysis showed an increase in the correlation between WSS and histopathology with aortic valve stenosis (r = -0.36; P = .002) and smaller aortic diameters (<4.5 cm: r = -0.39; P = .03). Elastic fiber thinning was associated with circumferential stiffness (r = -0.41; P = .06).

CONCLUSIONS

For patients with BAV, increased aortic valve-mediated WSS is significantly associated with elastic fiber thinning, particularly with aortic valve stenosis and in earlier stages of aortopathy. Elastic fiber thinning correlates with impaired tissue biomechanics. These novel findings further implicate valve-mediated hemodynamics in the progression of BAV aortopathy.

Accurate Orientation of the t-Branch Off-the-Shelf Multibranched Endograft After Deployment in Urgent Cases

Purpose: To evaluate the orientation of the standardized off-the-shelf multibranched t-Branch after implantation in urgent thoracoabdominal aortic aneurysm (TAAA) repairs, to characterize the impact of branch malorientation on procedural success, and to identify any predictive factors associated with malorientation. Methods: A retrospective analysis was conducted of 42 consecutive patients (mean age 73.3±7 years; 25 men) with urgent TAAA presentation treated with the t-Branch from January 2014 to June 2017. The primary objective was to quantify the preoperative clock position of the target vessels and determine any rotational deviation between the pre- and postoperative measurements and between the postoperative measurements and the standard branch configuration. Secondary outcomes were to identify factors influencing malorientation (>2 clock face hours) that could affect outcome. Results were compared for early (learning curve; n=18) vs late (n=24) experience and for adherence to (n=23) vs nonobservance of (n=19) the instructions for use (IFU). Results: Technical success was 93% (39/42). No significant difference in rotational deviation was identified between patients treated within the IFU vs outside the IFU. Seven (17%) patients had at least one target vessel maloriented after the procedure, which was not associated with total procedure time, fluoroscopy time, contrast volume, radiation dose, or adherence to the IFU. Female gender was associated with increased rotational deviation in postprocedure measurement for the celiac trunk (p=0.044) and superior mesenteric artery (SMA; p=0.006). Female gender was also associated with increased rotational deviation between the branch origin after deployment and the standard configuration of the t-Branch for every target vessel [celiac trunk (p=0.005), SMA (p=0.001), right renal artery (p=0.037), and left renal artery (p=0.003)]. Conclusion: The implantation of the t-Branch device in urgent cases achieved accurate apposition without rotational deviation between the target vessels and the position of the endograft branches. Gender may have an impact on orientation of the device. The t-Branch appears to have a “forgiving” nature for higher malorientation with no effect on procedure time, target vessel revascularization, or early branch patency.

Natural history of moderately dilated tubular ascending aorta: implications for determining the optimal imaging interval

OBJECTIVES

For a moderately dilated ascending aorta (diameter 35-54 mm), current guidelines recommend continuous annual or semi-annual examinations with computed tomography or magnetic resonance imaging. However, few data have shown the yield and benefit of such a protocol. This study aimed to investigate the fate of a moderately dilated ascending aorta and thereby determine the adequate imaging interval.

METHODS

In our institutional database, we identified adult patients having an ascending aortic diameter ≥40 mm in contrast-enhanced computed tomography and follow-up imaging(s) after ≥1 year. Of the 509 patients (mean age 67.2 ± 10.4 years) enrolled in the study, the maximal diameter of the ascending aorta was compared between the first and last images. Also, their medical records were reviewed to investigate the associated illness and clinical events.

RESULTS

The mean growth rate of the patients with a 40-44 mm ( n  = 321), 45-49 mm ( n  = 142) and ≥50 mm ( n  = 46) ascending aorta was 0.3 ± 0.5, 0.3 ± 0.5 and 0.7 ± 0.9 mm/year, respectively. During the mean interval of 4.3 ± 2.4 years, significant progression (diameter increase by ≥5 mm) occurred in 3.4, 5.6 and 21.7%, respectively. The 3- to 5-year rates of freedom from significant progression were 99.1%-96.5% (40-44 mm) and 97.8%-96.4% (45-49 mm). In multivariate analysis, initial ascending aortic diameter ≥45 mm and aortic valve regurgitation were significantly associated with significant progression. Acute type A aortic dissection occurred in 5 patients (1%), before the maximal diameter of the ascending aorta reached 55 mm or significant progression was observed.

CONCLUSIONS

For a moderately dilated ascending aorta not exceeding 45 mm in maximal diameter and stable in the first annual follow-up image, a 3- to 4-year interval would be reasonable before subsequent imaging. More frequent imaging may be warranted in patients with aortic valve insufficiency or with an aortic diameter ≥45 mm.

Early Outcomes of the t-Branch Off-the-Shelf Multibranched Stent-Graft in Urgent Thoracoabdominal Aortic Aneurysm Repair

Purpose: To assess the short-term outcomes of the multibranched off-the-shelf t-Branch stent-graft for urgent thoracoabdominal aortic aneurysm (TAAA) repair and to evaluate the impact on outcomes of the learning curve and adherence to the instruction for use (IFU). Methods: Between 2014 and 2017, 42 patients (mean age 73.3±7 years; 26 men) underwent urgent TAAA treatment using the t-Branch stent-graft [18 in the early (2014–2015) period and 24 in the late (2016–2017) period]. Nearly half the patients were symptomatic (n=18) and 12 had contained rupture. Aneurysm diameter >80 mm was present in 12 (mean diameter 77.7±13.2 mm). Nineteen patients did not meet the IFU for the t-Branch due to target vessel anatomy. The primary endpoints were spinal cord ischemia (SCI), renal function impairment, and 30-day mortality. Target vessel patency and endoleak incidence were assessed at 30 days. Multivariate analyses examined associations between perioperative variables and outcomes; the results are presented as the odds ratio (OR) and 95% confidence interval (CI). Results: The technical success rate was 93% (39/42). Successful catheterization was achieved in 150/155 target vessels (97%). The postoperative SCI rate was 21% (5 paraplegia/4 transient paraparesis) and was correlated with age (OR 1.26, 95% CI 1.01 to 1.56, p=0.04). The renal function impairment rate was 23% (10/42; 2 temporary, 2 permanent dialysis) and was correlated with early experience (OR 7.74, 95% CI 1.3 to 43.9, p=0.019). The 30-day mortality was 14% (no intraoperative deaths); no factor was associated with mortality. During the first month, the incidences of type I, II, and III endoleaks were 0%, 43%, and 0%, respectively; branch patency was 99% (150/151). Procedure time decreased in the later experience (479±333 vs 407±25 minutes, p=0.09), though it was increased in cases outside the IFU (497±135 vs 389±118 minutes, p=0.009), along with fluoroscopy time (121±48 vs 92±33 minutes, p=0.036). Conclusion: Endovascular repair of urgent TAAA using the t-Branch is a feasible treatment option with acceptable 30-day mortality and morbidity in terms of SCI and renal function impairment. Adherence to the IFU prolonged procedure time but had no effect on outcomes. Increased experience of such cases over time may improve outcomes.

Height alone, rather than body surface area, suffices for risk estimation in ascending aortic aneurysm

BACKGROUND

In international guidelines, risk estimation for thoracic ascending aortic aneurysm (TAAA) is based on aortic diameter. We previously introduced the aortic size index (ASI), defined as aortic size/body surface area (BSA), as a predictor of aortic dissection, rupture, and death. However, weight might not contribute substantially to aortic size and growth. We seek to evaluate the height-based aortic height index (AHI) versus ASI for risk estimation and revisit our natural history calculations.

METHODS

Aortic diameters and long-term complications of 780 patients with TAAA were analyzed. Growth rate estimates, yearly complication rates, and survival were assessed. Risk stratification was performed using regression models. The predictive value of AHI and ASI was compared.

RESULTS

Patients were stratified into 4 categories of yearly risk of complications based on their ASI and AHI. ASIs (cm/m²) of ≤2.05, 2.08 to 2.95, 3.00 to 3.95 and ≥4, and AHIs (cm/m) of ≤2.43, 2.44 to 3.17, 3.21 to 4.06, and ≥4.1 were associated with a 4%, 7%, 12%, and 18% average yearly risk of complications, respectively. Five-year complication-free survival was progressively worse with increasing ASI and AHI. Both ASI and AHI were shown to be significant predictors of complications (P < .05). AHI categories 3.05 to 3.69, 3.70 to 4.34, and ≥4.35 cm/m were associated with a significantly increased risk of complications (P < .05). The overall fit of the model using AHI was modestly superior according to the concordance statistic.

CONCLUSIONS

Compared with indices including weight, the simpler height-based ratio (excluding weight and BSA calculations) yields satisfactory results for evaluating the risk of natural complications in patients with TAAA.

Surgical Indication for Chronic Aortic Dissection in Descending Thoracic and Thoracoabdominal Aorta

BACKGROUND

To address the lack of information about the size of ruptures associated with chronic dissection in the descending and thoracoabdominal aorta, we evaluated the natural history of this pathology.

METHODS AND RESULTS

We analyzed data from 571 patients (mean age, 69.4±11.6 years) with unrepaired chronic aortic dissection in the descending or thoracoabdominal aorta with a maximal aortic diameter of ≥3.5 cm from 2007 to 2014. This was a cross-sectional study. Data on the timing of computed tomographic scan were as follows: for ruptured cases: at the time of rupture; for nonruptured cases: the initial aortic diameter. Patients with connective tissue disorders were excluded. The primary end point was evidence of aortic rupture on computed tomographic images. The median maximal diameter was 4.3 cm (limits, 3.5-9.0 cm) for all aortas and 5.6 cm (n=31; limits, 3.6-8.0 cm) for ruptured aortas. For aortic diameters of 4.0 to 4.4, 4.5 to 4.9, 5.0 to 5.4, 5.5 to 5.9, and 6.0 to 6.4 cm, the incidence of rupture was 0%, 3.3%, 15.3%, 18.8%, and 28.6%, respectively. The risk factors for rupture were absence of hypertension, chronic heart failure, chronic-phase dissection, and Yale index.

CONCLUSIONS

The risk of aortic rupture increased with an aortic diameter of ≥5.0 cm in patients with chronic aortic dissection in the descending or thoracoabdominal aorta. We would recommend 5.0 cm as an acceptable size for elective resection of subacute or chronic aortic dissection in the descending or thoracoabdominal aorta.

Molecular targets in aortic aneurysm for establishing novel management paradigms

Aortic aneurysm (AA) is a lethal disease and presents a large challenge for surgeons in the clinic. Although surgical management remains the major choice of AA, operative mortality remains high. With advances in understanding of the mechanisms of AAs, molecular targets, such as matrix metalloproteinases (MMPs), D-dimer, and inflammation markers, including C-reactive protein, interleukins and phagocytes, are important in the pathology of development of AA. These markers may become important for improving the diagnostic quality and provide more therapeutic choices for treatment of AA. Although these new markers require long-term trials before they can be translated into the clinic, they can still be helpful in determining new directions. The main aim of this review is to discuss the current findings of molecular targets in progression of AA and discuss the potential application of these new targets for managing this disease.

Natural history of aortic root aneurysms in Marfan syndrome

Background

Cardiovascular complications account for a significant proportion of the shortened lifespan of Marfan syndrome (MFS) patients, with aortic dissection being the most dreadful complication. The aortic root dilates initially in MFS patients, and given its important hemodynamic role, this can lead to aortic regurgitation and poses a substantial risk of aortic dissection. This study seeks to evaluate the natural history of aortic root aneurysms in MFS patients, with a focus on growth rates and correlation of root diameter with the risk of developing aortic complications.

Methods

Seventy-eight patients confirmed to have MFS and aortic root dilatation were retrospectively reviewed, and their aortic root diameters serially analyzed. Annual growth rate estimates and yearly rates of adverse events were computed and correlated with aortic diameter.

Results

The mean annual growth rate of the aortic root was estimated to be 0.26±0.05 cm/year (range 0.13 to 0.35 cm). Larger aneurysms grew faster, reaching up to 0.46 cm/year for aneurysms >6 cm. Mean age at onset of aortic dissection was 36±4 years. Annual rates of adverse events (rupture, dissection and death) were obtained using a logistic regression model at sizes 3.5, 4, 4.5, 5, 5.5 and 6 cm. A sharp increase of 23% in the probability of the risk of complications at diameters 5.5 to 6 cm was recognized.

Conclusions

Aortic root aneurysms in MFS patients tend to have a faster expansion rate compared to non-MFS individuals, with aortic root diameter having a significant impact on the yearly risk of developing aortic complications.

A machine learning approach to investigate the relationship between shape features and numerically predicted risk of ascending aortic aneurysm

Geometric features of the aorta are linked to patient risk of rupture in the clinical decision to electively repair an ascending aortic aneurysm (AsAA). Previous approaches have focused on relationship between intuitive geometric features (e.g., diameter and curvature) and wall stress. This work investigates the feasibility of a machine learning approach to establish the linkages between shape features and FEA-predicted AsAA rupture risk, and it may serve as a faster surrogate for FEA associated with long simulation time and numerical convergence issues. This method consists of four main steps: (1) constructing a statistical shape model (SSM) from clinical 3D CT images of AsAA patients; (2) generating a dataset of representative aneurysm shapes and obtaining FEA-predicted risk scores defined as systolic pressure divided by rupture pressure (rupture is determined by a threshold criterion); (3) establishing relationship between shape features and risk by using classifiers and regressors; and (4) evaluating such relationship in cross-validation. The results show that SSM parameters can be used as strong shape features to make predictions of risk scores consistent with FEA, which lead to an average risk classification accuracy of 95.58% by using support vector machine and an average regression error of 0.0332 by using support vector regression, while intuitive geometric features have relatively weak performance. Compared to FEA, this machine learning approach is magnitudes faster. In our future studies, material properties and inhomogeneous thickness will be incorporated into the models and learning algorithms, which may lead to a practical system for clinical applications.

Open Versus Endovascular or Hybrid Thoracic Aortic Aneurysm Repair

Thoracic aortic aneurysms are associated with significant morbidity and mortality. There are multiple underlying etiologies, including genetic abnormalities, that have important implications in their natural history. The variable histologic, anatomic, and clinical presentations necessitate careful consideration of available treatment options. Surgical repair of these aneurysms has been the mainstay of treatment; however, these approaches can carry a relatively high risk of morbidity and mortality. Endovascular approaches have now become first-line therapy for descending thoracic aneurysms, and with advancements in graft technology, endovascular approaches are being increasingly employed for hybrid repairs of the aortic arch and even the ascending aorta. However, to date, clinical outcomes from randomized trials and long-term follow-up are limited. As technology continues to advance, there is the potential for further integration of surgical and endovascular treatments so that patients have the best opportunity for a favorable outcome.

Surgery for Diseases of the Aortic Root

The aortic root is the junction between the heart and aorta, containing the aortic valve and the coronary artery ostia. Various pathologic conditions arise in this region requiring complex surgical correction. These include aneurysmal dilatation with and without aortic regurgitation, acute aortic dissection extending below the sinotubular junction, and infective endocarditis with valve and periannular destruction. Multiple strategies for correction of these complex surgical issues exist, with excellent early results and long-term survival.

The Genetics of Aortopathies in Clinical Cardiology

Aortopathies pose a significant healthcare burden due to excess early mortality, increasing incidence, and underdiagnosis. Understanding the underlying genetic causes, early diagnosis, timely surveillance, prophylactic repair, and family screening are keys to addressing these diseases. Next-generation sequencing continues to expand our understanding of the genetic causes of heritable aortopathies, rapidly clarifying their underlying molecular pathophysiology and suggesting new potential therapeutic targets. This review will summarize the pathogenetic mechanisms and management of heritable genetic aortopathies with attention to specific forms of both syndromic and nonsyndromic disorders, including Marfan syndrome, Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome, and familial thoracic aortic aneurysm and dissection.

Chiropractic Management of a Patient With Thoracic Pain and a Stable Thoracic Aortic Aneurysm: A Case Report

OBJECTIVE

The purpose of this case report was to describe chiropractic management of thoracic pain in a patient with a stable thoracic aortic aneurysm.

CLINICAL FEATURES

An 89-year-old man presented with axial mid- and upper back pain localized predominantly at the T8 and T1 spinal segmental levels. A review of available imaging revealed a stable aneurysmal dilatation of the ascending aorta, which measured 4.3 cm.

INTERVENTION AND OUTCOME

Because the thoracic pain was musculoskeletal in nature and the thoracic aortic aneurysm was stable, mechanical manipulation was provided using the Impulse adjusting instrument. The patient's pain was measured utilizing a numeric rating scale. The patient's thoracic pain improved over the course of treatment.

CONCLUSION

This patient was successfully treated for thoracic spine pain with a course of chiropractic care using a mechanical adjusting instrument.

Aortic shear stress in patients with bicuspid aortic valve with stenosis and insufficiency

OBJECTIVES

Bicuspid aortic valve, characterized by valve malformation and risk for aortopathy, displays profound alteration in systolic aortic outflow and wall shear stress distribution. The present study performed 4-dimensional flow magnetic resonance imaging in patients with bicuspid aortic valve with right-left cusp fusion, focusing on the impact of valve function on hemodynamic status within the ascending aorta.

METHODS

Four-dimensional flow magnetic resonance imaging was performed in 50 subjects with right-left bicuspid aortic valve and 15 age- and aortic size-matched controls with tricuspid aortic valve. Patients with bicuspid aortic valve were categorized into 3 groups according to their aortic valve function as follows: bicuspid aortic valve with no more than mild aortic valve dysfunction (bicuspid aortic valve control, n = 20), bicuspid aortic valve with severe aortic insufficiency (n = 15), and bicuspid aortic valve with severe aortic stenosis (n = 15).

RESULTS

All patients with right-left bicuspid aortic valve exhibited peak wall shear stress at the right-anterior position of the ascending aorta (bicuspid aortic valve vs trileaflet aortic valve at the right-anterior position: 0.91 ± 0.23 N/m² vs 0.43 ± 0.12 N/m², P < .001) with no distinct alteration between bicuspid aortic valve with severe aortic insufficiency and bicuspid aortic valve with severe aortic stenosis. The predominance of dilatation involving the tubular ascending aorta (82%, type 2 aortopathy) persisted, with or without valve dysfunction. Compared with bicuspid aortic valve control subjects, the bicuspid aortic valve with severe aortic insufficiency group displayed universally elevated wall shear stress (0.75 ± 0.12 N/m² vs 0.57 ± 0.09 N/m², P < .01) in the ascending aorta, which was associated with elevated cardiac stroke volume (P < .05). The bicuspid aortic valve with severe aortic stenosis group showed elevated flow eccentricity in the form of significantly increased standard deviation of circumferential wall shear stress, which correlated with markedly increased peak aortic valve velocity (P < .01).

CONCLUSIONS

The location of peak aortic wall shear stress and type of aortopathy remained homogeneous among patients with right-left bicuspid aortic valve irrespective of valve dysfunction. Severe aortic insufficiency or stenosis resulted in further elevated aortic wall shear stress and exaggerated flow eccentricity.

I-SWOT as instrument to individually optimize therapy of thoracoabdominal aortic aneurysms: Effective, norm-compliant and meeting the needs

Background

Guidelines summarize medical evidence, they identify the most efficient therapy under study conditions and recommend this therapy for use. The physician now has the challenge to translate a therapy that is efficient under laboratory conditions to a patient who is an individual person. To accomplish this task the physician has to make sure that (I) the ideal typical therapy is applicable and effective in this individual patient taking the special features into consideration, that (II) therapy is compliant with the norm including guidelines, laws and ethical requirements (conformity) and that (III) the therapy meets the patient’s needs.

Objective

How can physicians together with the patients translate the medical evidence into an individually optimized therapy?

Material and methods

At the German Aortic Center in Hamburg we use I‑SWOT as an instrument to identify such individually optimized therapy. With I‑SWOT, we present an instrument with which we have developed an (I) efficient, (II) conform and (III) needs-oriented therapeutic strategy for individual patients.

Results

I-SWOT cross-tabulates strengths (S) and weaknesses (W) related to therapy with opportunities (O) and threats (T) related to individual patients. This I‑SWOT matrix identifies four fundamental types of strategy, which comprise “SO” maximizing strengths and opportunities, “WT” minimizing weaknesses and threats, “WO” minimizing weaknesses and maximizing opportunities and “ST” maximizing strengths and minimizing threats. We discuss the case of a patient with asymptomatic thoracoabdominal aneurysm to show how I‑SWOT is used to identify an individually optimized therapy strategy.

Thoracic Aortic Aneurysm Growth: Role of Sex and Aneurysm Etiology

BACKGROUND

Thoracic aortic aneurysm (TAA) outcomes are worse in women than men, although reasons for sex differences are unknown. Because faster TAA growth is a risk factor for acute aortic syndromes, we sought to determine the role of sex and aneurysm etiology on TAA growth.

METHODS AND RESULTS

Eighty-two consecutive unoperated subjects with TAA who had serial aneurysm measurements were recruited. In multivariable linear regression the association of female sex with aneurysm growth rate was assessed after adjustment for potential confounders. We also tested the interaction term sex×aneurysm etiology in the prediction of TAA growth. Seventy-four percent of subjects were men; mean±SD age was 62.4±11.9 years in men and 67.7±10.7 years in women (P=0.06). Forty-seven (57%) subjects had degenerative TAAs, and the remainder had heritable TAAs. Absolute baseline aneurysm size and follow-up time were not different between men and women. Aneurysm growth rate was 1.19±1.15 mm/y in women and 0.59±0.66 mm/y in men (P=0.02). Female sex remained significantly associated with greater aneurysm growth in multivariable analyses (β±SE: 0.35±0.12, P=0.005). In addition, female sex was associated with faster TAA growth only among those with degenerative TAA (β±SE: 0.33±0.08, P=0.0002) and not among those with heritable TAA (P=0.79), with a significant sex×etiology interaction (P=0.001).

CONCLUSIONS

TAA growth rates are greater in women than men, and this difference is specific to women with degenerative TAAs. Our findings may explain sex differences in TAA outcomes and provide a foundation for future investigations of this topic.

Therapeutics Targeting Drivers of Thoracic Aortic Aneurysms and Acute Aortic Dissections: Insights from Predisposing Genes and Mouse Models

Thoracic aortic diseases, including aneurysms and dissections of the thoracic aorta, are a major cause of morbidity and mortality. Risk factors for thoracic aortic disease include increased hemodynamic forces on the ascending aorta, typically due to poorly controlled hypertension, and heritable genetic variants. The altered genes predisposing to thoracic aortic disease either disrupt smooth muscle cell (SMC) contraction or adherence to an impaired extracellular matrix, or decrease canonical transforming growth factor beta (TGF-β) signaling. Paradoxically, TGF-β hyperactivity has been postulated to be the primary driver for the disease. More recently, it has been proposed that the response of aortic SMCs to the hemodynamic load on a structurally defective aorta is the primary driver of thoracic aortic disease, and that TGF-β overactivity in diseased aortas is a secondary, unproductive response to restore tissue function. The engineering of mouse models of inherited aortopathies has identified potential therapeutic agents to prevent thoracic aortic disease.

International Registry of Patients Carrying TGFBR1 or TGFBR2 Mutations: Results of the MAC (Montalcino Aortic Consortium)

BACKGROUND

The natural history of aortic diseases in patients with TGFBR1 or TGFBR2 mutations reported by different investigators has varied greatly. In particular, the current recommendations for the timing of surgical repair of the aortic root aneurysms may be overly aggressive.

METHODS AND RESULTS

The Montalcino Aortic Consortium, which includes 15 centers worldwide that specialize in heritable thoracic aortic diseases, was used to gather data on 441 patients from 228 families, with 176 cases harboring a mutation in TGBR1 and 265 in TGFBR2. Patients harboring a TGFBR1 mutation have similar survival rates (80% survival at 60 years), aortic risk (23% aortic dissection and 18% preventive aortic surgery), and prevalence of extra-aortic features (29% hypertelorism, 53% cervical arterial tortuosity, and 27% wide scars) when compared with patients harboring a TGFBR2 mutation. However, TGFBR1 males had a greater aortic risk than females, whereas TGFBR2 males and females had a similar aortic risk. Additionally, aortic root diameter prior to or at the time of type A aortic dissection tended to be smaller in patients carrying a TGFBR2 mutation and was ≤45 mm in 6 women with TGFBR2 mutations, presenting with marked systemic features and low body surface area. Aortic dissection was observed in 1.6% of pregnancies.

CONCLUSIONS

Patients with TGFBR1 or TGFBR2 mutations show the same prevalence of systemic features and the same global survival. Preventive aortic surgery at a diameter of 45 mm, lowered toward 40 in females with low body surface area, TGFBR2 mutation, and severe extra-aortic features may be considered.

Sex Differences and Survival in Adults With Bicuspid Aortic Valves: Verification in 3 Contemporary Echocardiographic Cohorts

BACKGROUND

Sex-related differences in morbidity and survival in bicuspid aortic valve (BAV) adults are fundamentally unknown. Contemporary studies portend excellent survival for BAV patients identified at early echocardiographic-clinical stages. Whether BAV adults incur a survival disadvantage throughout subsequent echocardiographic-clinical stages remains undetermined.

METHODS AND RESULTS

Analysis was done of 3 different cohorts of consecutive patients with echocardiographic diagnosis of BAV identified retrospectively: (1) a community cohort of 416 patients with first BAV diagnosis (age 35±21 years, follow-up 16±7 years), (2) a tertiary clinical referral cohort of 2824 BAV adults (age 51±16 years, follow-up 9±6 years), and (3) a surgical referral cohort of 2242 BAV adults referred for aortic valve replacement (AVR) (age 62±14 years, follow-up 6±5 years). For the community cohort, 20-year risks of aortic regurgitation (AR), AVR, and infective endocarditis were higher in men (all P≤0.04); for a total BAV-related morbidity risk of 52±4% vs 35±6% in women (P=0.01). The cohort's 25-year survival was identical to that in the general population (P=0.98). AR independently predicted mortality in women (P=0.001). Baseline AR was more common in men (P≤0.02) in the tertiary cohort, with 20-year survival lower than that in the general population (P<0.0001); age-adjusted relative death risk was 1.16 (95% confidence interval [CI] 1.05-1.29) for men versus 1.67 (95% CI 1.38-2.03) for women (P=0.001). AR independently predicted mortality in women (P=0.01). Baseline AR and infective endocarditis were higher in men (both ≤0.001) for the surgical referral cohort, with 15-year survival lower than that in the general population (P<0.0001); age-adjusted relative death risk was 1.34 (95% CI 1.22-1.47) for men versus 1.63 (95% CI 1.40-1.89) for women (P=0.026). AR and NYHA class independently predicted mortality in women (both P≤0.04).

CONCLUSIONS

Within evolving echocardiographic-clinical stages, the long-term survival of adults with BAV is not benign, as both men and women incur excess mortality. Although BAV-related morbidity is higher in men in the community, and AR and infective endocarditis are more prevalent in men, women exhibit a significantly higher relative risk of death in tertiary and surgical referral cohorts, which is independently associated with AR.

Indications for Aortic Arch Intervention

Surgery of the aortic arch is arguably one of the most complex areas of cardiac surgery. Despite that, studies and guidelines have not sufficiently addressed the aortic arch specifically. In general, indications for aortic arch intervention parallel those of the ascending aorta. Herein we review indications for aortic arch intervention in various aortic pathologies based on the scant evidence available combined with surgical expertise and expert opinion.

Endovascular Repair For Thoracic Aortic Disease: Tertiary Single-center Experience In Northwestern Greece

The purpose of this article is to report the initial experience with endovascular repair of thoracic aortic disease in a single tertiary vascular unit in northwestern Greece.

Between 2003 and 2005, 16 patients were treated with endovascular techniques for various pathologies of the descending thoracic aorta. Twelve patients were treated electively and four emergently. Operative and follow-up data for a mean time of 18.4 months were retrospectively collected and analyzed.

Primary technical success was obtained in 14 (87.5%) cases. No early or late deaths occurred, and there was no major operation-related complication. No paraplegia was observed in our patients. Stent graft–related complications occurred in 18.75% (one type 2 and two type 3 endoleaks), but they all had a favorable outcome. No further problems have been reported in any of our patients.

Endovascular stent graft repair for diseases of the thoracic aorta seems to be a promising alternative to open surgery, especially for high-risk patients. Long-term results are needed to confirm the early benefit of this treatment option with regard to morbidity and mortality rates. The potential of this technique to be applicable even in relatively small, tertiary vascular centers might be of great benefit to patients.

Thoracic stent graft versus surgery for thoracic aneurysm

BACKGROUND

Thoracic aortic aneurysm (TAA) is an uncommon disease with an incidence of 10.4 per 100,000 inhabitants. It occurs mainly in older individuals and is evenly distributed among both sexes. There are no signs or symptoms indicative of the presence of the disease. Progressive but unpredictable enlargement of the dilated aorta is the natural course of the disease and can lead to rupture. Open chest surgical repair using prosthetic graft interposition has been a conventional treatment for TAAs. Despite improvements in surgical procedures perioperative complications remain significant. The alternative option of thoracic endovascular aneurysm repair (TEVAR) is considered a less invasive and potentially safer technique, with lower morbidity and mortality compared with conventional treatment. Evidence is needed to support the use of TEVAR for these patients, rather than open surgery. This is an update of the review first published in 2009.

OBJECTIVES

This review aimed to assess the efficacy of TEVAR versus conventional open surgery in patients with thoracic aortic aneurysms.

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist searched the Specialised Register (last searched January 2016) and CENTRAL (2015, Issue 12).

SELECTION CRITERIA

Randomised controlled trials in which patients with TAAs were randomly assigned to TEVAR or open surgical repair.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified and evaluated potential trials for eligibility. Excluded studies were further checked by another author. We did not perform any statistical analyses as no randomised controlled trials were identified.

MAIN RESULTS

We did not find any published or unpublished randomised controlled trials comparing TEVAR with conventional open surgical repair for the treatment of thoracic aortic aneurysms.

AUTHORS' CONCLUSIONS

Stent grafting of the thoracic aorta is technically feasible and non-randomised studies suggest reduction of early outcomes such as paraplegia, mortality and hospital stay. High quality randomised controlled trials assessing all clinically relevant outcomes including open-conversion, aneurysm exclusion, endoleaks, and late mortality are needed.

Characteristics and Outcomes of Ascending Versus Descending Thoracic Aortic Aneurysms

Thoracic aortic aneurysms (TAs) occur in reproducible patterns, but etiologic factors determining the anatomic distribution of these aneurysms are not well understood. This study sought to gain insight into etiologic differences and clinical outcomes associated with repetitive anatomic distributions of TAs. From 3,247 patients registered in an institutional Thoracic Aortic Center database from July 1992 to August 2013, we identified 844 patients with full aortic dimensional imaging by computerized axial tomography or magnetic resonance imaging scan (mean age 62.8 ± 14 years, 37% women, median follow-up 40 months) with TA diameter >4.0 cm and without evidence of previous aortic dissection. Patient demographic and imaging data were analyzed in 3 groups: isolated ascending thoracic aortic aneurysms (AAs; n = 628), isolated descending TAs (DTAs; n = 130), and combined AA and DTA (mixed thoracic aortic aneurysm, MTA; n = 86). Patients with DTA had more hypertension (82% vs 59%, p <0.001) and a higher burden of atherosclerosis (88% vs 9%, p <0.001) than AA. Conversely, patients with isolated AA were younger (59.5 ± 13.5 vs 71.0 ± 11.8 years, p <0.001) and contained almost every case of overt, genetically triggered TA. Patients with isolated DTA were demographically indistinguishable from patients with MTA. In follow-up, patients with DTA/MTA experienced more aortic events (aortic dissection/rupture) and had higher mortality than patients with isolated AA. In multivariate analysis, aneurysm size (odds ratio 1.1, 95% CI 1.07 to 1.16, p <0.001) and the presence of atherosclerosis (odds ratio 5.7, 95% CI 2.02 to 16.15, p <0.001) independently predicted adverse aortic events. We find that DTA with or without associated AA appears to be a disease more highly associated with atherosclerosis, hypertension, and advanced age. In contrast, isolated AA appears to be a clinically distinct entity with a greater burden of genetically triggered disease.

Pre- and Postoperative Imaging of the Aortic Root

Three-dimensional datasets acquired using computed tomography and magnetic resonance imaging are ideally suited for characterization of the aortic root. These modalities offer different advantages and limitations, which must be weighed according to the clinical context. This article provides an overview of current aortic root imaging, highlighting normal anatomy, pathologic conditions, imaging techniques, measurement thresholds, relevant surgical procedures, postoperative complications and potential imaging pitfalls. Patients with a range of clinical conditions are predisposed to aortic root disease, including Marfan syndrome, bicuspid aortic valve, vascular Ehlers-Danlos syndrome, and Loeys-Dietz syndrome. Various surgical techniques may be used to repair the aortic root, including placement of a composite valve graft, such as the Bentall and Cabrol procedures; placement of an aortic root graft with preservation of the native valve, such as the Yacoub and David techniques; and implantation of a biologic graft, such as a homograft, autograft, or xenograft. Potential imaging pitfalls in the postoperative period include mimickers of pathologic processes such as felt pledgets, graft folds, and nonabsorbable hemostatic agents. Postoperative complications that may be encountered include pseudoaneurysms, infection, and dehiscence. Radiologists should be familiar with normal aortic root anatomy, surgical procedures, and postoperative complications, to accurately interpret pre- and postoperative imaging performed for evaluation of the aortic root. Online supplemental material is available for this article.

Towards More Personalized Surgical Indications for Thoracic Aortic Dilatation: Are We There Yet?

Thoracic aortic aneurysms remain an important cause of death in the general population. The key to improving patient prognosis with thoracic aortic dilatation lies in early identification and tailored management strategies. Advances in the understanding of the molecular mechanisms of aneurysm formation, the natural history of disease, and clinical risk factors have led to significant improvements in patient management and overall outcomes. In the past decade, identification of the genetic basis of disease, together with wider availability of molecular testing, ushered in a new era for a tailored approach to the management of patients with thoracic aortic aneurysms. In this viewpoint, we explore these various iterative steps and future challenges.