Aortic Valve Repair: Where Are We Now?

Multiscale model for blood flow after a bileaflet artificial aortic valve implantation

Cardiovascular diseases are the leading cause of mortality in the world, mainly due to atherosclerosis and its consequences. The article presents the numerical model of the blood flow through artificial aortic valve. The overset mesh approach was applied to simulate the valve leaflets motion and to realize the moving mesh, in the aortic arch and the main branches of cardiovascular system. To capture the cardiac system's response and the effect of vessel compliance on the outlet pressure, the lumped parameter model has been also included within the solution procedure. Three different turbulence modeling approaches were used and compared - the laminar, k-ϵ and k-ω model. The simulation results were also compared with the model excluding the moving valve geometry and the importance of the lumped parameter model for the outlet boundary condition was analyzed. Proposed numerical model and protocol was found as suitable for performing the virtual operations on the real patient vasculature geometry. The time-efficient turbulence model and overall solving procedure allows to support the clinicians in making decisions about the patient treatment and to predict the results of the future surgery.

Standardized Aortic Valve Neocuspidization for Treatment of Aortic Valve Diseases

BACKGROUND

Aortic valve replacement is the traditional surgical treatment for aortic valve diseases, yet standardized aortic valve neocuspidization (AVNeo) is a promising alternative that is gaining popularity. The purpose of this article is to review the available published literature of AVNeo using glutaraldehyde-treated autologous pericardium, also known as the Ozaki procedure, including indications, outcomes, potential benefits, and modes of failure for the reconstructed valve.

METHODS

A comprehensive literature search was performed using keywords related to aortic valve repair, AVNeo, or Ozaki procedure. All articles describing performance of AVNeo were reviewed.

RESULTS

Reported early mortality after AVNeo varies from 0% to 5.88%. The largest cohort of patients in the literature includes 850 patients with an inhospital mortality rate of 1.88%. Cumulative incidence of aortic valve reoperation was 4.2% in the largest series. Reoperation was uncommon and mainly due to infective endocarditis or degeneration of the reconstructed valve (most commonly due to aortic valve regurgitation, rather than stenosis).

CONCLUSIONS

Aortic valve neocuspidization is a versatile and standardized alternative to aortic valve replacement with a biological prosthesis. Early to midterm outcomes from a number of centers are excellent and demonstrate the safety and durability of the procedure. Long-term outcomes and clinical trial data are necessary to determine which patients benefit the most from this procedure.

Age-related etiologies of aortic regurgitation with moderate or greater severity and coronary cusp bending: evaluation using transesophageal echocardiography

PURPOSE

The prevalence of valvular heart disease has been rising, especially among those ≥ 65 years of age, because of age-related valvular degeneration resulting in an increase in the number of patients diagnosed with aortic regurgitation (AR). We analyzed transesophageal echocardiography (TEE) images in AR patients to identify the etiologies and investigate any differences in them according to age.

METHODS

We studied 146 consecutive patients with chronic moderate or severe AR who underwent TEE. AR etiology was evaluated based on the TEE images in all the patients, as well as in each group separated by age.

RESULTS

The total number of patients eligible was 126 (mean age 67 ± 12 years), consisting of an older group (n = 85, mean age 74 ± 5 years) and younger group (n = 41, mean age 52 ± 11 years). In total, the most common etiology of AR was cusp bending (33.0%). In the older group, it was the most frequent as well (48.2%), with the right coronary cusp being the most commonly affected site (90.2%). In the younger group, bicuspid aortic valve was the most common (36.5%). Subsequently, all the study subjects were re-classified into two groups according to the presence/absence of cusp bending. Multivariate analysis revealed that age was the only factor associated with cusp bending.

CONCLUSION

Cusp bending was the most frequent etiology of AR in the elderly. Preoperative detection of cusp bending by TEE would expand the therapeutic strategy for AR, including aortic valvuloplasty.

Proper Orthogonal Decomposition Analysis of the Flow Downstream of a Dysfunctional Bileaflet Mechanical Aortic Valve

PURPOSE

Aortic valve replacement remains the only viable solution for symptomatic patients with severe aortic valve stenosis. Despite their improved design and long history of successful operation, bileaflet mechanical heart valves are still associated with post-operative complications leading to valve dysfunction. Thus, the flow dynamics can be highly disturbed downstream of the dysfunctional valve.

METHODS

In this in vitro study, the flow dynamics downstream of healthy and dysfunctional bileaflet mechanical heart valves have been investigated using particle image velocimetry measurements. Proper orthogonal decomposition of the velocity field has been performed in order to explore the coherent flow features in the ascending aorta in the presence of a dysfunctional bileaflet mechanical heart valve.

RESULTS

The ability of proper orthogonal decomposition derived metrics to differentiate between heathy and dysfunctional cases is reported. Moreover, reduced-order modeling using proper orthogonal decomposition is thoroughly investigated not only for the velocity field but also for higher order flow characteristics such as time average wall shear stress, oscillatory shear index and viscous energy dissipation.

CONCLUSION

Considering these results, proper orthogonal decomposition can provide a rapid binary classifier to evaluate if the bileaflet mechanical valve deviates from its normal operating conditions. Moreover, the study shows that the size of the reduced-order model depends on which flow parameter is required to be reconstructed.

Learning From Controversy: Contemporary Surgical Management of Aortic Valve Endocarditis

Aortic valve replacement is the commonest cardiac surgical operation performed worldwide for infective endocarditis (IE). Long-term durability and avoidance of infection relapse are goals of the procedure. However, no detailed guidelines on prosthesis selection and surgical strategies guided by the comprehensive evaluation of the extension of the infection and its microbiological characteristics, clinical profile of the patient, and risk of infection recurrence are currently available. Conventional mechanical or stented xenografts are the preferred choice for localized aortic infection. However, in cases of complex IE with the involvement of the root or the aortomitral continuity, the use of homograft is suggested according to the surgeon and center experience. Homograft use should be counterbalanced against the risk of structural degeneration. Prosthetic bioroot or prosthetic valved conduit (mechanical and bioprosthetic) are also potentially suitable alternatives. Further development of preservation techniques enabling longer durability of allogenic substitutes is required. We evaluate the current evidence for the use of valve substitutes in aortic valve endocarditis and propose an evidence-based algorithm to guide the choice of therapy. We performed a systemic review to clarify the contemporary surgical management of aortic valve endocarditis.

Optimizing outcomes in infective endocarditis: A comprehensive literature review

BACKGROUND

Despite being rare, infective endocarditis (IE) is a life-threatening disease with poor prognosis. New diagnostic and therapeutic strategies are emerging; however, predisposing factors and microbiology of the disease are also changing with time. Because of this, there has been a lack of reduction in the disease's incidence and new challenges for clinicians have arisen such as an increasingly aging population and growing antimicrobial resistance.

AIMS

In this paper, we aim to provide an overview of the changing trends in IE, current diagnosis, and management strategies, as well as the emerging role of the infective endocarditis teams in the care of patients with this disease.

MATERIALS & METHODS

A comprehensive electronic search was done utilizing PubMed, Ovid, SCOPUS, Embase and google scholar. The search terms included 'Endocarditis', 'IE', 'Infection', 'Vegetation', 'Duke criteria', 'native valve infection', 'prosthetic valve', 'valve infection', 'endocarditis outcome' and 'endocarditis bacteriology'. The references of the identified articles were then searched for any potential articles that can be included. The inclusion criteria were any article that discussed the evidence behind incidence and management of IE including the role of endocarditis team. The exclusion criteria were case reports, expert opinion, and editorials.

RESULTS

All the relevant findings are summarized in specified tables and within appropriate sections.

DISCUSSION

It is vital to determine the current trends in the epidemiology and microbiology of the condition so that the diagnostic threshold can be adapted, to identify new at-risk groups and achieve an accelerated evaluation strategy that allows for earlier diagnosis and treatment.

CONCLUSION

Management of IE can benefit from the input of different specialties, such as cardiology, cardiothoracic surgery, infectious disease, and microbiology. Therefore, adopting a multidisciplinary approach towards treatment is crucial to reduce morbidity and mortality from preventable complications of this pathology.

Pregnancy and cardiac interventions: What are the optimal management options?

Cardiac disease is the leading cause of maternal mortality in the United Kingdom. Major causes of cardiac death in pregnant women include cardiomyopathies, myocardial infarction, ischemic heart disease, and aortic dissection. Uncorrected congenital heart disease and women who have had corrective or palliative surgery may have complicated pregnancies as well. Some women with significant cardiac disease are unable to meet the increased physiological demands of pregnancy. Of these, those who do not respond to medical treatment may require surgical correction such as coronary artery bypass grafting. The risk of cardiac operations for pregnant women is similar to that for nonpregnant women but the fetal mortality rate remains high. Contributing factors to high fetal mortality rates include timing, urgency of operation, and the fetal/fetoplacental response to cardiopulmonary bypass. The aim of this review is to summarize current evidence in utilizing the different management approaches of cardiac issues during pregnancy.

Aortic valve repair or replacement in patients with aortic regurgitation: A systematic review and meta-analysis

OBJECTIVE

To systematically compare clinical outcomes between aortic valve repair and replacement in patients with aortic regurgitation.

METHODS

A comprehensive literature search was undertaken among the four major databases (PubMed, Embase, Scopus, and Ovid) to identify all published data comparing clinical outcomes of aortic valve repair vs replacement. Database searched from inception to November 2018.

RESULTS

A total of 1071 patients were analyzed in eight articles. Mean age was similar in both groups of patients (47.2 ± 12.8 vs 48.3 ± 12.7 years, P = 0.83, aortic valve repair and replacement, respectively). The preoperative left ventricular ejection fraction was better in the repair group (56.7% ± 4.8 vs 53.3% ± 4.2, P = 0.005). The rate of moderate-to-severe regurgitation and bicuspid aortic valve were similar in both cohorts (81% vs 78%, P = 0.90% and 58% vs 55%, P = 0.46). In-hospital and 1-year mortality was lower in repair cohort, although not reaching statistical significance (1.3% vs 3.6%, P = 0.12; 5.9% vs 9.3%, P = 0.77). Reoperation rate was higher in repair patients at 1 year (8.8% vs 3.7%, P = 0.03).

CONCLUSION

Aortic valve repair offers comparable perioperative outcomes to aortic valve replacement in aortic regurgitation patients at the expense of higher late reintervention rate. Larger trials with long-term follow-up are required to confirm the long-term benefits of aortic valve repair.