The Sievers Classification of the Bicuspid Aortic Valve for the Perioperative Echocardiographer: The Importance of Valve Phenotype for Aortic Valve Repair in the Era of the Functional Aortic Annulus

Sex differences in transcatheter aortic valve replacement outcomes among patients with bicuspid aortic stenosis

BACKGROUND

Despite comprising almost half of all patients undergoing valvular repair, data on transcatheter aortic valve replacement (TAVR) in patients with bicuspid aortic stenosis (BAS) are limited.

OBJECTIVE

We aimed to evaluate whether there are any sex differences in trends and outcomes of TAVR in this population.

METHODS

We utilized the National Inpatient Sample from 2012 to 2020 to identify admissions with BAS who underwent TAVR and analyzed trends and outcomes. Our primary outcome was in-hospital mortality and secondary outcomes were in-hospital complications. We used two models to adjust for demographics (A) and interventions (B).

RESULTS

Between 2012 to 2020, there were 76,540 hospitalizations for BAS patients who underwent AVR, among which 6,010 (7.9 %) underwent TAVR. There was an overall increasing trend in number of TAVR cases with a decreasing trend in mortality (2013: 8.7 %, 2020: 1.3 %). TAVR was performed more in males (61.1% vs 38.9 %). Despite the worse baseline characteristics in males, in-hospital mortality (2.4% vs. 1.5 %; OR: 1.584; 95 % CI: 0.621-4.038; p = 0.335) and secondary outcomes were similar across both sexes, even after adjusting for demographics and interventions.

CONCLUSION

TAVR in BAS has grown rapidly in the last decade. Males comprised the majority and had more comorbidities, but mortality and complications were similar in both sexes. Despite the increasing number of cases, a decreasing trend in mortality was observed for both sexes ultimately approaching that of SAVR, suggesting that TAVR may be a safe alternative among eligible males and females with bicuspid AS.

Imaging Modalities Employed in the TAVR Procedure With a Focus on CTA: What the Radiologist Needs to Know

RATIONALE AND OBJECTIVES

Aortic stenosis (AS) is one of the most common valvular heart disease. Symptomatic AS is associated with a high mortality rate which prompts fast intervention. The introduction of transcatheter aortic valve replacement (TAVR) has drastically improved the outcome of high surgical risk for mortality patients with severe AS. However, this procedure requires the employment of multimodality imaging in the pre-procedural planning, intra-procedural optimization, and post-procedural follow-up stages. This also requires an accurate understanding of the indications, measurements, strength, and limitations of each imaging modality during the different TAVR stages.

CONCLUSION

In this review, we aim to outline to radiologists the evidence-based approach and indications of different imaging modalities through the pre, peri, and post TAVR stages.

Point on the Aortic Bicuspid Valve

Background—Bicuspid aortic valve (BAV) disease is the most prevalent congenital heart disease in the world. Knowledge about its subtypes origin, development, and evolution is poor despite the frequency and the potential gravity of this condition. Its prognosis mostly depends on the risk of aortic aneurysm development with an increased risk of aortic dissection. Aims—This review aims to describe this complex pathology in way to improve the bicuspid patients’ management. Study design—We reviewed the literature with MEDLINE and EMBASE databases using MeSH terms such as “bicuspid aortic valve”, “ascending aorta”, and “bicuspid classification”. Results—There are various classifications. They depend on the criteria chosen by the authors to differentiate subtypes. Those criteria can be the number and position of the raphes, the cusps, the commissures, or their arrangements regarding coronary ostia. Sievers’ classification is the reference. The phenotypic description of embryology revealed that all subtypes of BAV are the results of different embryological pathogenesis, and therefore, should be considered as distinct conditions. Their common development towards aortic dilatation is explained by the aortic media’s pathological histology with cystic medial necrosis. At the opposite, BAV seems to display a profound genetic heterogeneity with both sporadic and familial forms. BAV can be even isolated or combined with other congenital malformations. Conclusions—All those characteristics make this pathology a highly complex condition that needs further genetic, embryological, and hemodynamic explorations to complete its well described anatomy.

Novel bicuspid aortic valve model with aortic regurgitation for hemodynamic status analysis using an ex vivo simulator

OBJECTIVE

The objective was to design and evaluate a clinically relevant, novel ex vivo bicuspid aortic valve model that mimics the most common human phenotype with associated aortic regurgitation.

METHODS

Three bovine aortic valves were mounted asymmetrically in a previously validated 3-dimensional-printed left heart simulator. The non-right commissure and the non-left commissure were both shifted slightly toward the left-right commissure, and the left and right coronary cusps were sewn together. The left-right commissure was then detached and reimplanted 10 mm lower than its native height. Free margin shortening was used for valve repair. Hemodynamic status, high-speed videography, and echocardiography data were collected before and after the repair.

RESULTS

The bicuspid aortic valve model was successfully produced and repaired. High-speed videography confirmed prolapse of the fused cusp of the baseline bicuspid aortic valve models in diastole. Hemodynamic and pressure data confirmed accurate simulation of diseased conditions with aortic regurgitation and the subsequent repair. Regurgitant fraction postrepair was significantly reduced compared with that at baseline (14.5 ± 4.4% vs 28.6% ± 3.4%; P = .037). There was no change in peak velocity, peak gradient, or mean gradient across the valve pre- versus postrepair: 293.3 ± 18.3 cm/sec versus 325.3 ± 58.2 cm/sec (P = .29), 34.3 ± 4.2 mm Hg versus 43.3 ± 15.4 mm Hg (P = .30), and 11 ± 1 mm Hg versus 9.3 ± 2.5 mm Hg (P = .34), respectively.

CONCLUSIONS

An ex vivo bicuspid aortic valve model was designed that recapitulated the most common human phenotype with aortic regurgitation. These valves were successfully repaired, validating its potential for evaluating valve hemodynamics and optimizing surgical repair for bicuspid aortic valves.

4D flow imaging of the thoracic aorta: is there an added clinical value?

Four-dimensional (4D) flow MRI has emerged as a powerful non-invasive technique in cardiovascular imaging, enabling to analyse in vivo complex flow dynamics models by quantifying flow parameters and derived features. Deep knowledge of aortic flow dynamics is fundamental to better understand how abnormal flow patterns may promote or worsen vascular diseases. In the perspective of an increasingly personalized and preventive medicine, growing interest is focused on identifying those quantitative functional features which are early predictive markers of pathological evolution. The thoracic aorta and its spectrum of diseases, as the first area of application and development of 4D flow MRI and supported by an extensive experimental validation, represents the ideal model to introduce this technique into daily clinical practice. The purpose of this review is to describe the impact of 4D flow MRI in the assessment of the thoracic aorta and its most common affecting diseases, providing an overview of the actual clinical applications and describing the potential role of derived advanced hemodynamic measures in tailoring follow-up and treatment.

State-of-the art bicuspid aortic valve repair in 2020

Patients with a bicuspid aortic valve (BAV) frequently require surgical intervention for aortic regurgitation (AR) and/or aneurysm. Valve-preserving surgery and repair of regurgitant BAVs have evolved into an increasingly used alternative to replacement. Anatomic predictors of possible repair failures have been identified and solutions developed. Using current techniques most non-calcified BAVs can be preserved or repaired. Excellent repair durability and freedom from valve-related complications can be achieved if all pathologic components of aortic valve and root including annular dilatation are corrected. Anatomic variations must be addressed using tailored approaches.

Contemporary Etiologies, Mechanisms, and Surgical Approaches in Pure Native Aortic Regurgitation

OBJECTIVE

To study contemporary etiologies, mechanisms, and corresponding surgical approaches in isolated aortic regurgitation (AR).

PATIENTS AND METHODS

Consecutive patients undergoing surgery for moderately severe and severe AR were retrospectively identified from January 1, 2006, through October 20, 2017. Intraoperative echocardiograms, surgical reports, and pathology reports were reviewed.

RESULTS

Of 382 patients (54±16 years, 82% men), there were 207 (54%) tricuspid (TAV), 167 (44%) bicuspid (BAV), 5 quadricuspid, and 3 unicuspid aortic valves. Isolated AR mechanisms (n=116, 30%) included cusp prolapse (n=44, 11%), restriction/retraction (n=33, 9%), aortic root dilatation (n=33, 9%), perforation (n=5, 1%), and fenestration (<1%); mixed mechanisms were present in 266 (70%). The most common mixed mechanism was root dilatation and prolapse (27% BAV vs 16% TAV, P=.01). Valve repair (AVr) was performed in 31% BAV and 23% TAV (P=.06). Aortic surgery was more common in BAV (37% vs 27%, P<.001). Overall, root dilatation was associated with AVr. In TAV, cusp prolapse and restriction/retraction were associated with replacement; in BAV, prolapse was associated with AVr. AR etiology was idiopathic in 43% TAV patients, 47% of whom had root dilatation.

CONCLUSIONS

BAV accounted for 44% of surgical referrals for AR and, compared with TAV, was more often associated with prolapse, root dilatation, and mixed mechanisms of AR. Because mechanisms affected the choice of AVr differently in BAV and TAV, comprehensive mechanistic description of surgical AR is critical.

The bicuspid aortic valve: Is it an immunological disease process?

Bicuspid aortic valves (BAVs) are the most common congenital cardiac condition and are characterized by a structural abnormality whereby the aortic valve is composed of two leaflets instead of being trileaflet. It is linked to an increased risk for a variety of complications of the aorta, many with an immunological pathogenesis. The aim of this study is to review and analyze the literature regarding immunological processes involving BAVs, associated common pathologies, and their incidence in the population. This study will also examine current trends in surgical and therapeutic approaches to treatment and discuss the future direction of BAV treatment.

Investigation of raphe function in the bicuspid aortic valve and its influence on clinical criteria-A patient-specific finite element study

The aortic valve is normally composed of 3 cusps. In one common lesion, 2 cusps are fused together. The conjoined area of the fused cusps is termed raphe. Occurring in 1% to 2% of the population, the bicuspid aortic valve (BAV) is the most common congenital cardiac malformation. The majority of BAV patients eventually require surgery. There is a lack in the literature regarding modeling of the raphe (geometry and material properties), its role and its influence on BAV function. The present study aims to propose improvements on these aspects. Three patient-specific finite element models of BAVs were created based on 3D trans-esophageal echocardiography measurements, and assuming age-dependent material properties. The raphe was initially given the same material properties as its underlying cusps. Two levels of validation were performed; one based on the anatomical validation of the pressurized geometry in diastole (involving 7 anatomical measures), as simulated starting from the unpressurized geometry, and the other based on a functional assessment using clinical measurements in both systole and diastole (involving 16 functional measures). The pathology was successfully reproduced in the FE models of all 3 patients. To further investigate the role of the raphe, 2 additional scenarios were considered; (1) the raphe was considered as almost rigid, (2) the raphe was totally removed. The results confirmed the interpretation of the raphe as added stiffness in the fused cusp's rotation with respect to the aortic wall, as well as added support for stress distribution from the fused cusps to the aortic wall.

Targeted next-generation sequencing identified ADAMTS5 as novel genetic substrate in patients with bicuspid aortic valve

BACKGROUND

Bicuspid Aortic Valve (BAV) is the most common congenital heart disease, affecting >1% of the general population. Up to date, three genes, NOTCH1, GATA5 and SMAD6, have been linked to the isolated form of BAV. However, potential genetic determinants remain largely unknown in most BAV patients.

MATERIAL AND METHODS

Targeted next-generation sequencing of 7 BAV candidate genes (NOTCH1, GATA5, SMAD6, NOS3, ADAMTS5, Alk2 and SMAD2) was performed in 32 BAV patients. Additional 35 BAV patients and 238 tricuspid aortic valve (TAV) patients, consisting of 107 patients from the transcatheter aortic valve implantation (TAVI) registry and 131 patients from the coronary artery disease (CAD) registry, were selected for further genotyping.

RESULTS

We found 2 rare non-synonymous variants in 2/7 genes in 3 BAV patients: one was NOTCH1:c.4297G>A and the other one was ADMTS5:c.935C>A that shared by two patients. NOTCH1:c.4297G>A has not been reported previously. ADMTS5:c.935C>A was predicted to be pathogenic by all applied algorithms. Alignment of protein sequences from all available species revealed that ADMTS5:p.Arg312Leu, produced by ADMTS5:c.935C>A, is located in a highly conserved region. The minor allele frequency of ADMTS5:c.935C>A in BAV patients was significantly higher than the matched population in TAV group (0.015 vs. 0, P=0.048).

CONCLUSION

Our results suggested that ADMTS5:c.935C>A are potentially associated with BAV. Further studies, such as large sample case-control replication test and functional research, are needed to explore the role of this rare variant in the development of BAV.

Aortic Valve Cusp Coaptation Surface Area Using 3-Dimensional Transesophageal Echocardiography Correlates with Severity of Aortic Valve Insufficiency

OBJECTIVE

The aim of this study was to test both in humans and using finite element (FE) aortic valve (AV) models whether the coaptation surface area (CoapSA) correlates with aortic insufficiency (AI) severity due to dilated aortic roots to determine the validity and utility of 3-dimensional transesophageal echocardiographic-measured CoapSA.

DESIGN

Two-pronged, clinical and computational approach.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 10 patients with known AI and 98 FE simulations of increasingly dilated human aortic roots.

INTERVENTIONS

The CoapSA was calculated using intraoperative 3-dimensional transesophageal echocardiography data of patients with isolated AI and compared with established quantifiers of AI. In addition, the CoapSA and effective regurgitant orifice area (EROA) were determined using FE simulations.

MEASUREMENTS AND MAIN RESULTS

In the 10 AI patients, regurgitant fraction (RF) increased with EROA (R² = 0.77, p = 0.0008); CoapSA decreased with RF (R² = 0.72, p = 0.0020); CoapSA decreased with EROA (R² = 0.71, p = 0.0021); and normalized CoapSA (CoapSA / [Ventriculo-Aortic Junction × Sinotubular Junction]) decreased with EROA (R² = 0.60, p = 0.0088). In the 98 FE simulations, normalized CoapSA decreased with EROA (R² = 0.50, p = 0.0001).

CONCLUSIONS

In both human and FE AV models, CoapSA was observed to be inversely correlated with AI severity, EROA, and RF, thereby supporting the validity and utility of 3D TEE-measured CoapSA. A clinical implication is the expectation that high values of CoapSA, measured intraoperatively after AV repairs, would correlate with better long-term outcomes of those repairs.

Dynamic Three-Dimensional Geometry of the Aortic Valve Apparatus-A Feasibility Study

OBJECTIVE

To provide (1) an overview of the aortic valve (AV) apparatus anatomy and nomenclature, and (2) data regarding the normal AV apparatus geometry and dynamism during the cardiac cycle obtained from three-dimensional transesophageal echocardiography (3D TEE).

DESIGN

Retrospective feasibility study.

SETTING

A single-center university teaching hospital.

PARTICIPANTS

The study was performed on data of 10 patients with a nonregurgitant, nonstenotic aortic valve undergoing cardiac surgery.

INTERVENTIONS

Intraoperative 3D TEE was performed on all the participants using the Siemens ACUSON SC2000 ultrasound system and Z6Ms transducer (Siemens Medical Systems, Mountainview, CA).

MEASUREMENTS AND MAIN RESULTS

Dynamic offline analyses were performed with Siemens eSie valve analytical software in a semiautomated fashion. Forty-five parameters were exported of which 13 were selected and analyzed. The cardiac cycle was divided into 4 quartiles to account for frame-rate variations. The annulus, sinus of Valsalva (SoV) and sinotubular junction (STJ) areas, diameter, perimeter and height, aortic leaflet height, leaflet coaptation height, and aortic valve-mitral valve angle changed significantly during the cardiac cycle (p < 0.001). STJ expanded more than both the annulus and the SoV (p < 0.001). The maximum aortic valve leaflet height change was greater in the left and right versus noncoronary leaflet (p < 0.001).

CONCLUSIONS

The semiautomated AV apparatus dynamic assessment using eSie valve software is a clinically feasible technique and can be performed readily in the operating room. It has the potential to significantly impact intraoperative decision-making in cases suitable for AV repair. The AV apparatus is a dynamic structure and demonstrates significant changes during the cardiac cycle.

A huge saccular aortic aneurysm compressing right coronary artery 7 years after aortic valve replacement due to bicuspid aortic valve insufficiency: A rare case report

BACKGROUND

In a patient underwent aortic valve replacement (AVR) due to bicuspid aortic valve (BAV) insufficiency without marked dilation of ascending aorta, the development of delayed-typed aneurysmal complication of ascending aorta has been often reported because the dilated aorta tends to grow insidiously with age.

CASE SUMMARY

A 58-year-old man who underwent AVR with mechanical valve due to severe aortic regurgitation secondary to BAV 7 years previously presented with exertional chest discomfort for 1 year. An echocardiography showed a well-functioning mechanical aortic valve without any significant abnormal findings. Cardiac multidetector computed tomography (MDCT) revealed a huge saccular aortic root aneurysm (79.7 mm × 72.8 mm in size) compressing the proximal right coronary artery resulting in ∼90% eccentric diffuse luminal narrowing. The patient subsequently underwent open-heart surgery with resection of the ascending aortic aneurysmal sac and consecutive ascending aorta and hemi-arch replacement using a graft.

CONCLUSION

After successful AVR in the patient with BAV insufficiency and mildly dilated ascending aorta, a regular aortic imaging such as cardiac MDCT with aortography would be helpful to monitor the morphology and size of ascending aorta and related complications to guide future management.