Comparative Histology of Aortic Dilatation Associated With Bileaflet Versus Trileaflet Aortic Valves

Insights From the Histopathologic Analysis of Acquired and Genetic Thoracic Aortic Aneurysms and Dissections

OBJECTIVE

The purpose of this study was to apply contemporary consensus criteria developed by the Society for Cardiovascular Pathology and the Association for European Cardiovascular Pathology to the evaluation of aortic pathology, with the expectation that the additional pathologic information may enhance the understanding and management of aortic diseases.

METHODS

A scoring system was applied to ascending aortic specimens from 42 patients with heritable thoracic aortic disease and known genetic variations and from 86 patients from a single year, including patients with known genetic variations (n = 12) and patients with sporadic disease (n = 74).

RESULTS

The various types of lesions of medial degeneration and the overall severity of medial degeneration overlapped considerably between those patients with heritable disease and those with sporadic disease; however, patients with heritable thoracic aortic disease had significantly more overall medial degeneration (P = .004) and higher levels of elastic fiber fragmentation (P = .03) and mucoid extracellular matrix accumulation (P = .04) than patients with sporadic thoracic aortic disease. Heritable thoracic aortic disease with known genetic variation was more prevalent in women than in men (27.2% vs 9.8%; P = .04), and women had more severe medial degeneration than men (P = .04). Medial degeneration scores were significantly lower for patients with bicuspid aortic valves than for patients with tricuspid aortic valves (P = .03).

CONCLUSION

The study's findings indicate considerable overlap in the pattern, extent, and severity of medial degeneration between sporadic and hereditary types of thoracic aortic disease. This finding suggests that histopathologic medial degeneration represents the final common outcome of diverse pathogenetic factors and mechanisms.

SPP1/osteopontin: a driver of fibrosis and inflammation in degenerative ascending aortic aneurysm?

Degenerative ascending aortic aneurysm (AscAA) is a silent and potentially fatal disease characterized by excessive vascular inflammation and fibrosis. We aimed to characterize the cellular and molecular signature for the fibrotic type of endothelial mesenchymal transition (EndMT) that has previously been described in degenerative AscAA. Patients undergoing elective open-heart surgery for AscAA and/or aortic valve repair were recruited. Gene expression in the intima-media of the ascending aorta was measured in 22 patients with non-dilated and 24 with dilated aortas, and candidate genes were identified. Protein expression was assessed using immunohistochemistry. Interacting distal gene enhancer regions were identified using targeted chromosome conformation capture (HiCap) in untreated and LPS-treated THP1 cells, and the associated transcription factors were analyzed. Differential expression analysis identified SPP1 (osteopontin) as a key gene in the signature of fibrotic EndMT in patients with degenerative AscAA. The aortic intima-media expression of SPP1 correlated with the expression of inflammatory markers, the level of macrophage infiltration, and the aortic diameter. HiCap analysis, followed by transcription factor binding analysis, identified ETS1 as a potential regulator of SPP1 expression under inflammatory conditions. In conclusion, the present findings suggest that SPP1 may be involved in the development of the degenerative type of AscAA. KEY MESSAGES: In the original manuscript titled "SPP1/osteopontin, a driver of fibrosis and inflammation in degenerative ascending aortic aneurysm?" by David Freiholtz, Otto Bergman, Saliendra Pradhananga, Karin Lång, Flore-Anne Poujade, Carl Granath, Christian Olsson, Anders Franco-Cereceda, Pelin Sahlén, Per Eriksson, and Hanna M Björck, we present novel findings on regulatory factors on osteopontin (SPP1) expression in immune cells involved in degenerative ascending aortic aneurysms (AscAA). The central findings convey: SPP1 is a potential driver of the fibrotic endothelial-to-mesenchymal transition in AscAA. SPP1/osteopontin expression in AscAA is predominately by immune cells. ETS1 is a regulatory transcription factor of SPP1 expression in AscAA immune cells.

Are acute type A aortic dissections atherosclerotic?

Background

Type A aortic dissections (TAAD) are devastating aortic complications. Patients with Marfan syndrome, a bicuspid aortic valve or a thoracic aortic aneurysm have an increased risk to develop a TAAD. These predisposing conditions are characterized by a histologically thin intimal layer and hardly any atherosclerosis. Little is known about the susceptibility for atherosclerosis in patients with a type A aortic dissection.

Objective

We aim to systematically describe atherosclerotic lesions in TAAD patients.

Materials and methods

A total of 51 patients with a TAAD (mean age 62.5 ± 10.8 years, 49% females) and 17 control patients (mean age 63 ± 5.5 years, 53% females) were included in this study. Cardiovascular risk factors were assessed clinically. All sections were stained with Movat pentachrome and hematoxylin eosin. Plaque morphology was classified according to the modified AHA classification scheme proposed by Virmani et al.

Results

In the TAAD group thirty-seven percent were overweight (BMI > 25). Diabetes and peripheral arterial disease were not present in any of the patients. Fifty-nine percent of the patients had a history of hypertension. The intima in TAAD patients was significantly thinner as compared to the control group (mean thickness 143 ± 126.5 μm versus 193 ± 132 μm, p < 0.023). Seven TAAD patients had a normal intima without any form of adaptive or pathological thickening. Twenty-three TAAD patients demonstrated adaptive intimal thickening. Fourteen had an intimal xanthoma, also known as fatty streaks. A minority of 7 TAAD patients had progressive atherosclerotic lesions, 4 of which demonstrated pathological intimal thickening, 3 patients showed early fibroatheroma, late fibroatheroma and thin cap fibroatheroma. In the control group the majority of the patients exhibited progressive atherosclerotic lesions: three pathologic intimal thickening, two early fibroatheroma, six late fibroatheroma, one healed rupture and two fibrotic calcified plaque.

Discussion

This study shows that TAAD patients hardly exhibit any form of progressive atherosclerosis. The majority of TAAD patients showcase non-progressive intimal lesions, whereas the control group mostly demonstrated progressive intimal atherosclerotic lesions. Findings are independent of age, sex, or the presence of (a history of) hypertension.

Medial degeneration and atherosclerosis show discrete variance around the circumference of ascending aorta aneurysms

Medial degeneration is the most common histological finding in ascending aortic aneurysms with lesser but significant involvement by atherosclerosis. The overall extent and severity can be potentially underrated because of their uneven distribution and macroscopic inconspicuousness of medial degeneration. This study aims to compare the distribution of degenerative and atherosclerotic lesions around ascending aorta circumference, also considering aortic valve cuspidity. We evaluated 88 cases of resected ascending aortae, 25 with a tricuspid aortic valve and 63 with a malformed aortic valve, oriented by a cardiac surgeon and sent for pathological examination. We applied the consensus documents from 2015 and 2016 for microscopic evaluation of aortic specimens. The medial degeneration and atherosclerosis were graded semi-quantitatively for each aortic quadrant: convexity, anterior wall, concavity, and posterior wall. Nearly all quadrants showed at least mild medial degeneration; more severe findings of medial degeneration and atherosclerosis were in the aneurysms associated with the tricuspid valve. In the aneurysms with the tricuspid aortic valve, there was more frequent and more severe atherosclerosis at the concavity than at the anterior wall (p = .046); the frequency and severity of medial degeneration did not differ significantly. The aneurysms with a malformed aortic valve showed more severe medial degeneration at the concavity compared to the convexity (p = .011); atherosclerosis was less common and did not show any significant differences. More than half of the samples also revealed at least a one-grade (mostly one-grade) difference among the quadrants in individual cases for both atherosclerosis and medial degeneration. Extreme differences were rare except for atherosclerosis in the tricuspid group. The results revealed only slight overall differences around the aortic circumference, with concavity being the most susceptible. Still, thanks to occurring inter- and intraindividual variability, the examination of all quadrants seems meaningful not to miss the most severe changes and to underscore the findings.

Patient-derived microphysiological model identifies the therapeutic potential of metformin for thoracic aortic aneurysm

Background

Thoracic aortic aneurysm (TAA) is the permanent dilation of the thoracic aortic wall that predisposes patients to lethal events such as aortic dissection or rupture, for which effective medical therapy remains scarce. Human-relevant microphysiological models serve as a promising tool in drug screening and discovery.

Methods

We developed a dynamic, rhythmically stretching, three-dimensional microphysiological model. Using patient-derived human aortic smooth muscle cells (HAoSMCs), we tested the biological features of the model and compared them with native aortic tissues. Drug testing was performed on the individualized TAA models, and the potentially effective drug was further tested using β-aminopropionitrile-treated mice and retrospective clinical data.

Findings

The HAoSMCs on the model recapitulated the expressions of many TAA-related genes in tissue. Phenotypic switching and mitochondrial dysfunction, two disease hallmarks of TAA, were highlighted on the microphysiological model: the TAA-derived HAoSMCs exhibited lower alpha-smooth muscle actin expression, lower mitochondrial membrane potential, lower oxygen consumption rate and higher superoxide accumulation than control cells, while these differences were not evidently reflected in two-dimensional culture flasks. Model-based drug testing demonstrated that metformin partially recovered contractile phenotype and mitochondrial function in TAA patients’ cells. Mouse experiment and clinical investigations also demonstrated better preserved aortic microstructure, higher nicotinamide adenine dinucleotide level and lower aortic diameter with metformin treatment.

Interpretation

These findings support the application of this human-relevant microphysiological model in studying personalized disease characteristics and facilitating drug discovery for TAA. Metformin may regulate contractile phenotypes and metabolic dysfunctions in diseased HAoSMCs and limit aortic dilation.

Funding

This work was supported by grants from National Key R&D Program of China (2018YFC1005002), National Natural Science Foundation of China (82070482, 81771971, 81772007, 51927805, and 21734003), the Science and Technology Commission of Shanghai Municipality (20ZR1411700, 18ZR1407000, 17JC1400200, and 20YF1406900), Shanghai Municipal Science and Technology Major Project (2017SHZDZX01), and Shanghai Municipal Education Commission (Innovation Program 2017-01-07-00-07-E00027). Y.S.Z. was not supported by any of these funds; instead, the Brigham Research Institute is acknowledged.

Ascending aortic wall degeneration in patients with bicuspid versus tricuspid aortic valve

Background

The magnitude of ascending aortic degeneration in patients with bicuspid aortic valves (BAV) is controversial.

Methods

The aim of this study was to investigate ascending aortic wall degeneration in patients with BAV as compared with tricuspid aortic valves (TAV). The ascending aortic wall of 67 consecutive patients was processed for histology and immunohistochemistry. The extent of surgery and wall degeneration were investigated. Unadjusted survival was evaluated by Kaplan–Meier analysis. Median follow-up for patients with BAV and TAV was 3.8 years (interquartile range [IQR] 3.5–4.1) and 3.7 years (IQR 3.4–3.9), respectively.

Results

There were 33 patients with BAV and 34 with TAV. Mid-ascending aorta diameter was 54 mm (IQR 50–60). Replacement of the aortic valve, together with an ascending aortic prosthesis, was more frequent in BAV vs TAV patients (24% vs. 3%, P = 0.013). However, medial fibrosis, elastic fiber thinning, incremental medial degeneration and smooth muscle cell nuclei loss were less prominent in BAV vs TAV patients (0.1 ± 0.4 vs. 0.8 ± 1.4, P = 0.016; 0.6 ± 1.4 vs. 1.6 ± 2.0, P = 0.027; 1.7 ± 0.7 vs. 2.2 ± 0.8, P = 0.045 and 2.3 ± 1.5 vs. 3.2 ± 1.3, P = 0.026, respectively).

Conclusions

Since degeneration of the ascending aortic wall was seldom prominent, histopathology alone may not support the need for surgery of the dilated ascending aorta in BAV patients as compared with TAV patients.

Aortic Root Anatomy Is Related to the Bicuspid Aortic Valve Phenotype

BACKGROUND

Bicuspid aortic valve (BAV) is associated with an asymmetric (not circular) aortic root, resulting in variability in the aortic root diameter measurements obtained using different techniques. The objective of this study was to describe aortic root asymmetry, including its orientation in the thorax, in relation to the various phenotypes of BAV and its impact on aortic root diameter measurements obtained using transthoracic echocardiography.

METHODS

Aortic root asymmetry, orientation of the largest root diameter, and orientation of the valve opening were studied using computed tomographic scans of patients with BAV without significant aortic valve dysfunction referred for evaluation of a thoracic aortic aneurysm. Eighty-five patients with BAV were evaluated; BAV with fusion of the left and the right coronary cusps (L-R BAV), with or without raphe (n = 63), was compared with BAV with fusion of the right coronary and noncoronary cusps (N-R BAV), with or without raphe (n = 22).

RESULTS

Asymmetry of the aortic root and its orientation in the thorax can be predicted from BAV phenotype: orientation of the valve opening differed from orientation of the largest root diameter by nearly 75° in both groups. The angle of the largest root diameter with the reference sagittal plane was 64.3° in the L-R BAV group versus 143.1° in the N-R BAV group (P < .0001). Therefore, using the parasternal long-axis view on transthoracic echocardiography, in N-R BAV, the ultrasound beam is roughly parallel to the valve opening orientation and almost orthogonal to the maximum diameter of the root. On the contrary, in L-R BAV, the ultrasound beam is roughly perpendicular to the valve opening orientation and almost parallel to the maximum diameter of the root. Consequently, the parasternal long-axis view on transthoracic echocardiography significantly underestimates maximal aortic root diameter in N-R BAV and modestly underestimates root diameter in L-R BAV (-6.1 ± 0.96 vs -2.3 ± 0.47 mm, P = .0008).

CONCLUSIONS

Aortic root morphology in patients with BAV can be predicted by BAV phenotype: the largest root diameter is roughly perpendicular to the orientation of the valve opening. Therefore, echocardiographic measurements according to present recommendations (parasternal long-axis view) underestimate maximal diameter in patients with N-R BAV.

Histopathological changes in dilated ascending aorta associated with aortic valve cuspidity

OBJECTIVES

Patients with a bicuspid aortic valve (BAV) often present with a dilated ascending aorta. However, the underlying pathogenesis for the observed changes in the aortic wall and the resulting aneurysmal dilation remains a subject of debate. This study aims to compare the histological abnormalities of the ascending aorta in BAV and tricuspid aortic valve (TAV) patients and their correlation with aortic diameter and patient age.

METHODS

A total of 376 patients from our institution's clinical database were included in the retrospective analysis. These patients underwent either elective surgery for ascending aorta dilation or emergency surgery for aortic dissection, either isolated or with a structurally diseased aortic valve. After excision, the ascending aorta samples were analysed by a pathologist.

RESULTS

On histological examination, a higher degree of elastic fibre fragmentation and loss and mucoid extracellular matrix accumulation was present in the samples from TAV patients when compared with that from BAV patients (P < 0.001). However, correlation was poor for all variables when considering aortic diameter and histological abnormalities or age and histological abnormalities in both BAV and TAV patients.

CONCLUSIONS

Our study demonstrates a greater incidence of severe histological abnormalities in TAV patients when compared with BAV patients.

Ascending aorta dissection in a new classification system: Clinicopathological features of 62 cases

Herein we present a single institution 5-year experience with ascending aorta dissection biopsies depicting the clinicopathological features of 62 cases. To detect microscopic abnormalities in the aortic wall beside the dissection itself, we applied a new histopathological classification scheme from the consensus documents issued by The Society for Cardiovascular Pathology and The Association for the European Cardiovascular Pathology in 2015 and 2016. The most common finding was medial degeneration (MD) - 61 cases (98.4%); atherosclerosis (AS) was found in 19 aortae (30.6%), and chronic aortitis- giant cell pattern described in one aorta (1.6%). The medial degeneration constituents included mucoid matrix accumulation, smooth muscle cells and elastic fibers abnormalities, and medial fibrosis. The consensus document application led to increased MD reporting compared to older studies and to our previous experience, probably due to assessing more subtle and focal changes such as intralamellar fibrosis, intralamellar mucoid matrix accumulation, and loss of smooth muscle cell nuclei- these changes being also the most common MD abnormalities we are reporting. We have compared the results in patients with bicuspid (n = 7; 11.3%) versus tricuspid (n = 55; 88.7%) aortic valve, suggesting no significant differences except for translamellar fibrosis, which appeared to be more severe in the bicuspid valve group (p = 0.0397). The results might imply similar histopathological findings regardless of the aortic valve cuspidity in aortic dissection. These findings are in contrast to ascending aorta dilation (aneurysm), where more severe medial degeneration changes have been described in patients with the tricuspid aortic valve.

Impact of histopathological changes in ascending aortic diseases

AIMS

To better understand relationship between histological medial degenerative changes (MDC), pathological status [thoracic aorta aneurysm (TAA), thoracic aorta dissection (TAD), bicuspid aortic valve (BAV), and non-BAV] and aortic size at imaging.

METHODS AND RESULTS

We collected 496 ascending aorta surgical specimens from patients with degenerative aortic diseases (mean age, 61 years) whose imaging data were available, including BAV in 191 (TAD 4%, TAA 96%) and with non-BAV in 305 (TAD 45%, TAA 55%). We analyzed them according to the pathology consensus statement and scored MDC [elastic fiber fragmentation and/or loss (EFFL); smooth muscle nuclei loss (SMNL); mucoid extracellular matrix accumulation (MEMA), intralamellar (I) or translamellar (T)] and measured medial wall thickness on correlation with imaging data and the status (TAA, TAD, BAV, or non-BAV). In TAA subset, EFFL, SMNL and MEMA-T scores were lower in BAV than in non-BAV. In relation to the aortic diameter, EFFL, SMNL and MEMA-T scores were more important in TAD subset than in TAA at the small aortic diameters. Independent predictors of aortic dissection included thicker medial wall (odds ratio [OR], 6.3; 95% confidence interval [CI], 2.4 to 17.6; p < 0.0001) and greater SMNL score (OR, 1.2; 95% CI, 1.1 to 1.3; p = 0.003).

CONCLUSIONS

This large cohort study confirms that non-BAV aortas present higher MDC scores than BAV aortas. Higher MDC scores are correlated with increased aortic diameter. TAD can occur not infrequently in smaller aortas associated with high MDC scores. This suggests that risk stratification of aortic dissection based on aorta dimensions is imperfect.

Clinical Significance of Aortic Root Modification Associated With Bicuspid Aortic Valve in Marfan Syndrome

BACKGROUND

Both bicuspid aortic valve (BAV) and Marfan syndrome have been associated with aortic dissection risk, but it is unknown whether the presence of BAV is associated with an increased aortic risk in patients with an FBN1 gene mutation. We evaluated aortic diameters, aortic valve function, and aortic shape in Marfan syndrome patients with and without BAV and reported aortic events during follow-up.

METHODS

All patients with an FBN1 gene mutation evaluated in our clinic were included. Aortic root diameters were measured, and the aortic valve was studied using echocardiography at each visit.

RESULTS

Of the 1437 patients with an FBN1 gene mutation, 26 patients (1.8%) had a BAV. Both aortic root maximal diameter and normalized Z score were larger at all ages, in patients with BAV when compared with patients with tricuspid aortic valve. Prophylactic aortic root surgery tended to be performed in younger patients when BAV was present, although aortic diameter threshold was similar in the 2 populations. No aortic dissection was observed in Marfan syndrome patients with BAV.

CONCLUSIONS

In patients with a FBN1 mutation, BAV is associated with larger aortic root diameter, with no difference in evolution of Z score with age. We found a trend towards prophylactic aortic root surgery at younger ages but similar aortic diameter thresholds without occurrence of aortic dissection. We did not find any evidence for lowering aortic diameter thresholds used to propose preventive aortic root surgery in the presence of BAV in patients with FBN1 mutations.

Management of Adults With Normally Functioning Congenitally Bicuspid Aortic Valves and Dilated Ascending Aortas

We describe herein a 65-year-old woman who underwent resection of a dilated (5.1 cm) ascending aorta associated with a normally functioning congenitally bicuspid aortic valve. The patient provided the framework to discuss proper management-operative versus nonoperative-of the dilated ascending aorta associated with a normally functioning bicuspid aortic valve. Unfortunately, there is inadequate data to provide an unequivocal answer to this dilemma. Operative intervention requires that the short-term risk of the prophylactic procedure be considerably lower than the long-term risk of aortic dissection/rupture without operative intervention. Because there is no proof that operative intervention provides less morbidity and lower mortality, nonoperative management at this time seems to be the better approach.

Outcomes and Quality of Life After Ross Reintervention: Would You Make the Same Choice Again?

BACKGROUND

The Ross procedure was introduced as a long-term if not definitive solution for aortic pathology. However, the rate of reoperation is not negligible.

METHODS

This single-center prospective study assessed the general outcome of Ross reoperation and patients' perceived quality of life compared with 2 control groups (Ross non-reoperation and mechanical aortic valve replacement). Patient's preference regarding the choice between mechanical aortic valve and Ross procedure was investigated in a subgroup that could theoretically have been directed to either of the 2 procedures.

RESULTS

Between 2005 and 2017, 64 consecutive patients underwent reoperation after Ross. Median age was 31 years. Median freedom from reoperation after the Ross procedure was 136 months. An autograft reoperation was required in 49, and 25 had homograft failure. No in-hospital death was recorded. Mean follow-up was 77 months (range, 6-164 months). Quality of life was assessed with the 36-Item Short Form Health Survey questionnaire. The Ross reoperation group showed a lower score involving psychological concerns compared with the other groups. In the reoperated-on patients group, 52 had adequate aortic annulus dimensions to receive a prosthetic valve instead of a Ross procedure. When asked whether they would make the same choice, only 31% confirmed the preference.

CONCLUSIONS

Reoperations after Ross procedure have low mortality and morbidity. Long-term follow-up showed a high quality of life, even after reoperations. However, owing to psychological concerns after the redo operation, when choosing a Ross procedure, it is our duty to thoroughly explain to patients that a high level of disillusion is predictable in case of reoperations.

The American Association for Thoracic Surgery consensus guidelines on bicuspid aortic valve-related aortopathy: Full online-only version

Bicuspid aortic valve disease is the most common congenital cardiac disorder, being present in 1% to 2% of the general population. Associated aortopathy is a common finding in patients with bicuspid aortic valve disease, with thoracic aortic dilation noted in approximately 40% of patients in referral centers. Several previous consensus statements and guidelines have addressed the management of bicuspid aortic valve-associated aortopathy, but none focused entirely on this disease process. The current guidelines cover all major aspects of bicuspid aortic valve aortopathy, including natural history, phenotypic expression, histology and molecular pathomechanisms, imaging, indications for surgery, surveillance, and follow-up, and recommendations for future research. It is intended to provide clinicians with a current and comprehensive review of bicuspid aortic valve aortopathy and to guide the daily management of these complex patients.

Is there a role for autophagy in ascending aortopathy associated with tricuspid or bicuspid aortic valve?

Autophagy is a conserved process by which cytoplasmatic elements are sequestered in vesicles and degraded after their fusion with lysosomes, thus recycling the precursor molecules. The autophagy-mediated removal of redundant/harmful/damaged organelles and biomolecules plays not only a replenishing function, but protects against stressful conditions through an adaptive mechanism. Autophagy, known to play a role in several pathological conditions, is now gaining increasing attention also in the perspective of the identification of the pathogenetic mechanisms at the basis of ascending thoracic aortic aneurysm (TAA), a localized or diffused dilatation of the aorta with an abnormal widening greater than 50 percent of the vessel's normal diameter. TAA is less frequent than abdominal aortic aneurysm (AAA), but is encountered with a higher percentage in patients with congenital heart disease or known genetic syndromes. Several biological aspects of TAA pathophysiology remain to be elucitated and therapeutic needs are still widely unmet. One of the most controversial and epidemiologically important forms of TAA is that associated with the congenital bicuspid malformation of the aortic valve (BAV). Dysregulated autophagy in response, for example, to wall shear stress alterations, has been demonstrated to affect the phenotype of vascular cells relevant to aortopathy, with potential consequences on signaling, remodeling, and angiogenesis. The most recent findings and hypotheses concerning the multiple aspects of autophagy and of its dysregulation are summarized, both in general and in the context of the different vascular cell types and of TAA progression, with particular reference to BAV-related aortopathy.

Polyamines and microbiota in bicuspid and tricuspid aortic valve aortopathy

Polyamines are small aliphatic cationic molecules synthesized via a highly regulated pathway and involved in general molecular and cellular phenomena. Both mammalian cells and microorganisms synthesize polyamines, and both sources may contribute to the presence of polyamines in the circulation. The dominant location for microorganisms within the body is the gut. Accordingly, the gut microbiota probably synthesizes most of the polyamines in the circulation in addition to those produced by the mammalian host cells. Polyamines are mandatory for cellular growth and proliferation. Established evidence suggests that the polyamine spermidine prolongs lifespan and improves cardiovascular health in animal models and humans through both local mechanisms, involving improved cardiomyocyte function, and systemic mechanisms, including increased NO bioavailability and reduced systemic inflammation. Higher levels of polyamines have been detected in non-dilated aorta of patients affected by bicuspid aortic valve congenital malformation, an aortopathy associated with an increased risk for thoracic ascending aorta aneurysm. In this review, we discuss metabolism of polyamines and their potential effects on vascular smooth muscle and endothelial cell function in vascular pathology of the thoracic ascending aorta associated with bicuspid or tricuspid aortic valve.

Evolution of Precision Medicine and Surgical Strategies for Bicuspid Aortic Valve-Associated Aortopathy

Bicuspid aortic valve (BAV) is a common congenital cardiac malformation affecting 1–2% of people. BAV results from fusion of two adjacent aortic valve cusps, and is associated with dilatation of the aorta, known as bicuspid valve associated aortopathy. Bicuspid valve aortopathy is progressive and associated with catastrophic clinical events, such as aortic dissection and rupture. Therefore, frequent monitoring and early intervention with prophylactic surgical resection of the proximal aorta is often recommended. However, the specific pattern of aortopathy is highly variable among patients, with different segments of the ascending aorta being affected. Individual patient risks are sometimes difficult to predict. Resection strategies are informed by current surgical guidelines which are primarily based on aortic size and growth criteria. These criteria may not optimally reflect the risk of important aortic events. To address these issues in the care of patients with bicuspid valve aortopathy, our translational research group has focused on validating use of novel imaging techniques to establish non-invasive hemodynamic biomarkers for risk-stratifying BAV patients. In this article, we review recent efforts, successes, and ongoing challenges in the development of more precise and individualized surgical approaches for patients with bicuspid aortic valves and associated aortic disease.

Fate of remnant sinuses of Valsalva in patients with bicuspid and trileaflet valves undergoing aortic valve, ascending aorta, and aortic arch replacement

OBJECTIVE

In patients presenting with aortic valvulopathy with concomitant ascending aortic aneurysm, surgical management of the sinus of Valsalva segment remains undefined, especially for moderately dilated aortic roots. In patients with this pathology undergoing aortic valve replacement with supracoronary ascending aorta replacement, we assessed the fate of the remnant preserved sinus of Valsalva segment stratified by aortic valve morphology and pathology.

METHODS

From 2002 to 2015, 428 patients underwent elective aortic valve replacement with supracoronary ascending aorta replacement. Patients were stratified on the basis of valvular morphology (bicuspid aortic valve [n = 254] and tricuspid aortic valve [n = 174]), valvular pathology (bicuspid aortic valve with aortic stenosis [n = 178], bicuspid aortic valve with aortic insufficiency [n = 76], tricuspid aortic valve with aortic stenosis [n = 61], tricuspid aortic valve with aortic insufficiency [n = 113]), and preoperative sinus of Valsalva dimensions (<40, 40-45, >45 mm).

RESULTS

Kaplan-Meier analysis revealed no significant difference in freedom from reoperation in tricuspid aortic valve versus bicuspid aortic valve (P = .576). Multivariable Cox regression model performed with sinus of Valsalva dimensions at baseline and follow-up as time-varying covariates did not adversely affect survival. A repeated-measure, mixed-effects model constructed to assess longitudinal sinus of Valsalva trends revealed that the retained sinus of Valsalva dimensions remain stable over long-term follow-up (discharge to ≥10 years), irrespective of valvular morphology/pathology (bicuspid aortic valve with aortic insufficiency, tricuspid aortic valve with aortic insufficiency, tricuspid aortic valve with aortic stenosis) and preoperative sinus of Valsalva groups (<40, 40-45, >45 mm).

CONCLUSIONS

In patients with nonaneurysmal sinuses of Valsalva undergoing aortic valve replacement with supracoronary ascending aorta replacement, the sinus segment can be preserved irrespective of the type of valvular pathology (aortic stenosis vs aortic insufficiency) or valvular morphology (bicuspid aortic valve vs tricuspid aortic valve). Aortic valve replacement with supracoronary ascending aorta replacement may have a stabilizing effect on the sinus segment over long-term follow-up in patients with tricuspid aortic valves or bicuspid aortic valves.

Year in review: bicuspid aortopathy

PURPOSE OF REVIEW

This article outlines the key research contribution to bicuspid aortic valve (BAV) aortopathy over the past 18 months.

RECENT FINDINGS

Investigators have further defined the current gaps in knowledge and the scope of the clinical problem of BAV aortopathy. Support for aggressive resection strategies is waning as evidence mounts to suggest that BAV is not similar to genetic connective tissue disorders with respect to aortic risks. The role of cusp fusion patterns and valve-mediated hemodynamics in disease progression is a major area of discovery. Molecular and cellular mechanisms remain elusive and contradictory.

SUMMARY

BAV aortopathy is a major public health problem that remains poorly understood. New insights on valve-mediated hemodynamics using novel imaging modalities may lead to more individualized resection strategies and improved clinical guidelines.