Valve-sparing aortic root replacement

Nature of aortic annulus: Influence of annulus dynamic on the aortic valve hemodynamics

Accurate imaging reports of the aortic valve indicate that the diameter of the aortic annulus changes regularly during a cardiac cycle. Most of these studies aim to demonstrate the proper method for estimating the aortic annulus diameter before performing TAVR surgery, revealing that the aortic annulus is dynamic and not constant throughout the cardiac cycle. This raises the question of how fixing the aortic annulus might affect valve function, which is a question that still needs to be addressed. Therefore, the present study seeks to address this question and elucidate the dynamic impact of the aortic annulus on aortic valve hemodynamics. Two computational models based on this hypothesis were created and solved, and then their results were compared. Both models are identical, except for the intrinsic dynamic nature of the aortic annulus. One model consists of the dynamic behavior, and the other simulates a fixed annulus, resembling the effect of a TAVR operation, SAVR, or any phenomenon that eliminates the dynamic nature of the annulus. Our research findings indicate that the dynamic nature of the annulus enhances blood flow (+2.7 %), increases mean velocity (+11.9) and kinetic energy density (+34 %), prolongs momentum retention during systole, stabilizes the flow jet at the end of systole, reduces the required pressure to keep the leaflets open (-40.9 % at 0.3s), and sustains ventricular pressure superiority (+9.4 %) over the aorta for a longer duration (+17.7 % of systole), a crucial factor in preventing backflow during aortic valve closure. Based on these results, more attention should be paid to the dynamic nature of the annulus.

Importance of surgeon's experience in practicing valve-sparing aortic root replacement

Background

Valve-sparing root replacement (VSRR) requires a unique skill set. This study aimed to examine the influence of surgeon's procedural volume on outcomes of VSRR.

Methods

This retrospective study included 1697 patients from 2 large, high-volume aortic centers who underwent aortic root replacement (ARR) between 2004 and 2021 and were potentially eligible for VSRR. Surgeons were classified as performing <5 ARRs or ≥5 ARRs annually. Multivariable logistic regression was used to examine the independent association of surgeon volume and the decision to perform VSRR. Inverse probability treatment weighting (IPTW) was used to match patients who were operated on by <5 ARR surgeons or ≥5 ARR surgeons and compare long-term survival probability. Cumulative incidence curves with mortality as a competing risk were plotted to compare the rate of aortic valve reoperation.

Results

Of 1697 patients who met the study inclusion criteria, 944 underwent composite-valve conduit ARR and 753 underwent VSRR. The median age of the cohort was 57 years (interquartile range, 45-66 years), and 268 (15.8%) were female. Aortic insufficiency was present in 1105 patients (65.1%), and 200 of the procedures (11.8%) were reoperations. The indication for surgery was aneurysm in 1496 patients (88.2%) and dissection in 201 (11.8%). Among the 743 patients who underwent VSRR, 691 (92%) were operated on by ≥ 5 ARR surgeons and 62 (8%) were operated on by <5 ARR surgeons. In multivariable logistic regression, ≥5 ARRs (odds ratio, 3.33; 95% confidence interval, 2.34-4.73; P < .001) was associated with VSRR as the procedure of choice. Following IPTW, there was no significant difference between <5 ARR and ≥5 ARR surgeons in survival probability after VSRR (P = .59) or in the rate of aortic valve reoperation (P = .60).

Conclusions

In the setting of a high-volume aortic center, patients who undergo ARR are less likely to receive VSRR if operated on by a <5 ARR surgeon; however, VSRR may be safely performed by <5 ARR surgeons.

Potential predictors of severe cardiovascular involvement in Marfan syndrome: the emphasized role of genotype-phenotype correlations in improving risk stratification-a literature review

BACKGROUND

Marfan syndrome (MFS) is a genetically determined systemic connective tissue disorder, caused by a mutation in the FBN1 gene. In MFS mainly the cardiovascular, musculoskeletal and ocular systems are affected. The most dangerous manifestation of MFS is aortic dissection, which needs to be prevented by a prophylactic aortic root replacement.

MAIN BODY

The indication criteria for the prophylactic procedure is currently based on aortic diameter, however aortic dissections below the threshold defined in the guidelines have been reported, highlighting the need for a more accurate risk stratification system to predict the occurrence of aortic complications. The aim of this review is to present the current knowledge on the possible predictors of severe cardiovascular manifestations in MFS patients, demonstrating the wide range of molecular and radiological differences between people with MFS and healthy individuals, and more importantly between MFS patients with and without advanced aortic manifestations. These differences originating from the underlying common molecular pathological processes can be assessed by laboratory (e.g. genetic testing) and imaging techniques to serve as biomarkers of severe aortic involvement. In this review we paid special attention to the rapidly expanding field of genotype-phenotype correlations for aortic features as by collecting and presenting the ever growing number of correlations, future perspectives for risk stratification can be outlined.

CONCLUSIONS

Data on promising biomarkers of severe aortic complications of MFS have been accumulating steadily. However, more unifying studies are required to further evaluate the applicability of the discussed predictors with the aim of improving the risk stratification and therefore the life expectancy and quality of life of MFS patients.

Current trends in aortic valve-preserving surgery

The natural history of aortic regurgitation is not as benign as once believed, even in asymptomatic patients with preserved left ventricular function. Aortic valve surgery can prolong survival in these patients. However, both mechanical and biological aortic valve replacement have major disadvantages, especially in young patients. Aortic valve-preserving surgery has attracted a great deal of attention because it has a significant survival benefit over replacement. Nonetheless, aortic valve-preserving surgery has not been widely adopted due to the complexity of the technique and assessment (i.e., long learning curve). With recent technical and theoretical advances, aortic valve-preserving surgery has increasingly been performed with better outcomes, and therefore earlier surgical intervention in cases of aortic regurgitation has been considered. Recent advances in aortic valve-preserving surgery include repair-oriented classification of the etiology of aortic regurgitation, objective assessment of the cusp configuration (i.e., effective height and geometric height), use of aortic annuloplasty, introduction of two reproducible valve-sparing root replacement procedures (i.e., aortic valve reimplantation and aortic root remodeling techniques), standardization of aortic valve-preserving surgery, and assessment of cusp configuration with aortoscopy. A number of prospective multicenter studies are currently underway and will clarify the role of aortic valve-preserving surgery in the treatment of aortic regurgitation in the near future.

Biomechanical characterization and comparison of different aortic root surgical techniques

OBJECTIVES

Understanding the biomechanical impact of aortic valve-sparing techniques is important in an era in which surgical techniques are developing and are increasingly being used based on biomechanical understanding that is essential in the refining of existing techniques. The objective of this study was to describe how the valve-sparing remodelling (Yacoub) and reimplantation (David Type-1) techniques affect the biomechanics of the native aortic root in terms of force distribution and geometrical changes.

METHODS

Two force transducers were implanted into 22 pigs, randomized to 1 of 3 groups (David = 7, native = 7 and Yacoub = 8) along with 11 sonomicrometry crystals and 2 pressure catheters. Force and geometry data were combined to obtain the local structural stiffness in different segments of the aortic root.

RESULTS

The radial structural stiffness was not different between groups (P = 0.064) at the annular level; however, the David technique seemed to stabilize the aortic annulus more than the Yacoub technique. In the sinotubular junction, the native group was more compliant (P = 0.036) with the right-left coronary segment than the intervention groups. Overall, the native aortic root appeared to be more dynamic at both the annular level and the sinotubular junction than both intervention groups.

CONCLUSIONS

In conclusion, the David procedure may stabilize the aortic annulus more than the Yacoub procedure, whereas the leaflet opening area was larger in the latter (P = 0.030). No difference (P = 0.309) was found in valve-opening delay between groups. The 2 interventions show similar characteristics at the sinotubular junction, whereas the David technique seemed more restrictive at the annular level than the Yacoub technique.

Aortic valve repair for aortic regurgitation and preoperative echocardiographic assessment

Aortic valvuloplasty (AVP) has been performed less frequently than mitral valvuloplasty. The survival benefit of AVP over replacement has been demonstrated. Therefore, standardization of AVP is crucial for its widespread adoption. The hemodynamic advantage of AVP of preserving the native aortic valve may be one reason for the survival benefit. Recent guidelines still recommend AVP in selected cases compared with the less restricted recommendation for mitral valvuloplasty, although recent studies have proposed earlier indication for surgical intervention. Indication for aortic root replacement is also still conservative, especially in Japan. However, more liberal root replacement should be recommended for better repair when AVP is indicated. Theoretically, all aortic regurgitation lesions can be repaired with acceptable durability. However, restricted cusp should be extended by a pericardial patch, which itself has emerged as a risk of recurrence. Therefore, indications for aortic regurgitation for type III lesions should be determined carefully. Special consideration is crucial for bicuspid aortic valve repair; prevention of postoperative stenosis is especially important. Arrangement of the commissure position is the most important consideration for this purpose, although it remains controversial. Therefore, detailed diagnosis is important in planning AVP, and echocardiography plays a key role in this process.

Early and Midterm Outcomes of the VSSR procedure with De Paulis valsalva graft: A Chinese single-Center Experience in 38 patients

Background

This study investigated early and midterm outcomes after valve-sparing aortic root replacement (VSSR procedure with De Paulis Valsalva graft) for acute aortic dissection or ascending aortic aneurysm in a single Chinese hospital center.

Methods

Between September 2005 to July 2013, 38 patients (84.2 % male; mean age, 45.5 ± 12.4) underwent VSSR procedure with De Paulis valsalva graft for acute aortic dissection or ascending aortic aneurysm and were followed up clinically and echocardiographically.

Results

Among the 38 cases studied, intensive care unit stay duration was 34.5 (interquartile range, 16–34.6) days; hospital stay duration was 11.7 ± 7.9 days; operation time was 6.8 ± 1.9 h; and cross-clamping time was 154.4 ± 42.0 min. There was one intraoperative conversion to Bentall procedure; one re-operation for bleeding; one operative death and one case who developed complications. Mean follow-up was 39.7 ± 21.7 months (range, 12–108 months; cumulative rate, 1483 patients-months; follow-up rate, 94 %). At 5 and 10 years, overall freedom from valve replacement was 94 % and 87 %; freedom from aortic regurgitation grade II or higher was 94 % and 91 %; and freedom from reoperation was 94 % and 90 % years, respectively.

Conclusions

The reimplantation type of valve-sparing procedure appears to be facilitated by the use of the De Paulis valsalva graft with satisfactory perioperative and midterm results.

Aortic Involvement in Pediatric Marfan syndrome: A Review

Outlining specific protocols for the management of pediatric patients with Marfan syndrome has been challenging. This is mostly due to a dearth of clinical studies performed in pediatric patients. In Marfan syndrome, the major sources of morbidity and mortality relate to the cardiovascular system. In this review, we focus on aortic involvement seen in pediatric patients with Marfan syndrome, ranging from aortic dilatation to aortic rupture and heart failure. We discuss the histological, morphological, and pathogenetic basis of the cardiac manifestations seen in pediatric Marfan syndrome and use a specific case to depict our experienced range of cardiovascular manifestations. The survival for patients with Marfan syndrome may approach the expected survival for non-affected patients, with optimal management. With this potentiality in mind, we explore possible and actual management considerations for pediatric Marfan syndrome, examining both medical and surgical therapy modalities that can make the possibility of improved survival a reality.

Early results of modified aortic-valve sparing partial root replacement in acute type A aortic dissection with an intimal tear in the aortic sinuses

We describe a modified aortic valve-sparing partial root replacement (AVSPRR) technique for acute type A aortic dissection with an intimal tear (IT) in the aortic sinus. This procedure consists of selective replacement of the sinus containing an IT with a rectangular patch. If an IT exists in any coronary sinus, the coronary button was reimplanted to the neo-sinus and an external wrapping of the noncoronary sinus was added. Modified AVSPRR may be considered a feasible short-term outcome, and may be considered as an option in selected patients.

The anatomy of the aortic root

The aortic root is the anatomical bridge between the left ventricle and the ascending aorta. It is made up of the aortic valve leaflets, which are supported by the aortic sinuses (of Valsalva), and the interleaflet triangles interposed between the basal attachments of the leaflets. As such, it possesses significant length, and because of the semilunar attachment of the leaflets, there is no discrete proximal border to the root. It is limited distally, nonetheless, by the supravalvar ridge, or sinutubular junction. Descriptions of the aortic root over the years have been bedeviled by accounts of a valve anulus. There are at least two rings within the root, but neither serves to support the valve leaflets, each leaflets being attached in semilunar fashion from the sinutubular junction to a basal ventricular attachment Two leaflets are supported by muscle, and the third has an exclusively fibrous attachment. The root acts as a bridging structure not only anatomically, separating the myocardial and arterial components of the left ventricular pathway, but also functionally, since its proximal and distal components can withstand considerable changes in ventricular and arterial pressures. In this review, we describe the anatomy of this crucial cardiac component, emphasizing the current problems which have arisen due to indiscriminate descriptions of a nonexistent anulus.

The importance of interleaflet triangles for aortic valve competence in a marfan patient with dilated aortic sinuses

We report a case of advanced aortic sinus aneurysm without the aggravation of aortic valve regurgitation after a simple reduction procedure for dilated aortic root base and sinotubular junction (STJ) in a Marfan patient with annuloaortic ectasia and severe aortic valve regurgitation. The aortic valve competence was well preserved by limited change of distances among the interleaflet triangles after reduction of the dilated aortic root base and STJ in the Marfan patient, although the sinus dilatation was aggravated.