Reimplantation Versus Remodeling: A Meta-Analysis

Current controversies in aortic valve-preserving surgery

The clinical outcome of severe aortic regurgitation (AR) remains suboptimal, but surgery has been shown to have survival benefit over medical therapy. Postoperative survival is inferior in patients with reduced left ventricular function, and therefore early surgical intervention is recommended. Aortic valvuloplasty (AVP) is an attractive option to avoid the major drawbacks of prosthetic valves but has not been widely adopted. The etiology of AR is classified functionally into three groups: normal leaflet motion (type I), cusp prolapse (type II), and restriction (type III). Type I with dilatation of the sinus of Valsalva (type Ib) can be repaired by aortic valve reimplantation or aortic root remodeling with similar valve stability. Type I with dilatation of the aortic annulus (type Ic) can be managed by annuloplasty. Type II can be corrected by plication or resuspension techniques. Pericardial patch is necessary in AVP for type Id (perforation/fenestration) and type III but is associated with risk of recurrence. Bicuspid aortic valve is classified according to commissure angle: symmetrical, asymmetrical, and very asymmetrical. Tricuspidization is recommended for repair of very asymmetrical valves to avoid postoperative stenosis. Recent progress has achieved similar reoperation rates between bicuspid and tricuspid aortic valve repair. For Marfan syndrome, valve-sparing root replacement is advantageous compared to Bentall operation regarding late survival, thromboembolic and hemorrhagic events, and endocarditis. Similar findings have been reported in acute aortic dissection. Both remodeling and reimplantation procedures provide similar favorable outcomes in these settings. Recent advances in AVP are summarized by quantitative assessment of cusp configuration (effective height and geometric height), graft size decision, use of template to cut the graft, and videoscopic assessment of post-repair cusp configuration. Due to these advances, AVP shows superior results to replacement surgery. Further concrete evidence with larger case volumes and longer observation periods are necessary to popularize AVP.

Progress in surgical interventions for aortic root aneurysms and dissections

INTRODUCTION

: The aortic root is a uniquely sensitive region as it anatomically encompasses the aortic valve leaflets and gives origin to the coronary arteries. These associated structures, in addition to the aortic tube, itself, add immensely to the complexity of replacing this segment when it is aneurysmal or dissected. Given this complexity, many contemporary choices for treatment of aortic root aneurysms have evolved over the past few decades.

AREAS COVERED

The aim of this study was to provide an updated review of the literature regarding various surgical options for management of aortic root aneurysmal disease. A systematic search in Pubmed database was performed for articles related to various aortic root surgeries and outcomes published between 1998 to 2020.

EXPERT OPINION

: For multiple technical options in aortic root replacement surgery, decades of surgical investigation and development have shown favorable results, which provide a formidable armamentarium to be used at the discretion of the surgeon to suit various patient anatomic patterns and risk profile-while still durably controlling the aortic pathology and protecting from recurrence, valve dysfunction, progressive dilatation, and aortic dissection.

Comprehensive Ex Vivo Comparison of 5 Clinically Used Conduit Configurations for Valve-Sparing Aortic Root Replacement Using a 3-Dimensional-Printed Heart Simulator

Supplemental Digital Content is available in the text.

Background:

Many graft configurations are clinically used for valve-sparing aortic root replacement, some specifically focused on recapitulating neosinus geometry. However, the specific impact of such neosinuses on valvular and root biomechanics and the potential influence on long-term durability are unknown.

Methods:

Using a custom 3-dimenstional–printed heart simulator with porcine aortic roots (n=5), the anticommissural plication, Stanford modification, straight graft (SG), Uni-Graft, and Valsalva graft configurations were tested in series using an incomplete counterbalanced measures design, with the native root as a control, to mitigate ordering effects. Hemodynamic and videometric data were analyzed using linear models with conduit as the fixed effect of interest and valve as a fixed nuisance effect with post hoc pairwise testing using Tukey’s correction.

Results:

Hemodynamics were clinically similar between grafts and control aortic roots. Regurgitant fraction varied between grafts, with SG and Uni-Graft groups having the lowest regurgitant fractions and anticommissural plication having the highest. Root distensibility was significantly lower in SG versus both control roots and all other grafts aside from the Stanford modification (P≤0.01 for each). All grafts except SG had significantly higher cusp opening velocities versus native roots (P<0.01 for each). Relative cusp opening forces were similar between SG, Uni-Graft, and control groups, whereas anticommissural plication, Stanford modification, and Valsalva grafts had significantly higher opening forces versus controls (P<0.01). Cusp closing velocities were similar between native roots and the SG group, and were significantly lower than observed in the other conduits (P≤0.01 for each). Only SG and Uni-Graft groups experienced relative cusp closing forces approaching that of the native root, whereas relative forces were >5-fold higher in the anticommissural plication, Stanford modification, and Valsalva graft groups.

Conclusions:

In this ex vivo modeling system, clinically used valve-sparing aortic root replacement conduit configurations have comparable hemodynamics but differ in biomechanical performance, with the straight graft most closely recapitulating native aortic root biomechanics.

Reimplantation versus remodeling in valve-sparing surgery for aortic root aneurysms: a meta-analysis

Background

Valve-sparing aortic root replacement (VSARR), which includes reimplantation and remodeling techniques, has been developed as an important treatment for aortic root aneurysms. We aimed to evaluate the outcomes of reimplantation versus remodeling techniques in valve-sparing surgery for aortic root aneurysms.

Methods

A systematic review and meta-analysis was performed by searching PubMed, Embase and the Cochrane Library until November 2019. Fourteen retrospective cohort studies comparing reimplantation with remodeling techniques for aortic root aneurysms were included and contained at least one of the following outcomes: early mortality, late mortality, aortic valve-related reoperation, and postoperative moderate to severe aortic regurgitation (AR).

Results

The outcomes of 1,672 patients (1,011 underwent reimplantation surgery, and 661 underwent remodeling) were analyzed. Compared with remodeling, the reimplantation technique was associated with a significantly lower risk of late mortality (RR =0.34; 95% CI, 0.17–0.71; P=0.004; I²=37%) and reoperation (RR =0.31; 95% CI, 0.12–0.76; P=0.01; I²=55%). There was no significant difference in early mortality (RR =0.69; 95% CI, 0.31–1.53; P=0.36; I²=0%), postoperative moderate to severe AR (RR =0.64; 95% CI, 0.31–1.32; P=0.22; I²=36%) or postoperative stroke (RR =1.26; 95% CI, 0.58–2.75; P=0.56; I²=0%) between the two groups. No evidence of publication bias was detected.

Conclusions

The current meta-analysis indicate that patients who undergo reimplantation procedures have a significantly lower risk of late mortality and reoperation than those who undergo remodeling procedures. Early mortality, postoperative moderate to severe AR and stroke were comparable between the two techniques.

Valve-sparing root replacement and composite valve graft replacement in patients with aortic regurgitation: From the Japan Cardiovascular Surgery Database

OBJECTIVES

The advantage of valve-sparing root replacement (VSRR) over aortic root replacement with a composite valve graft (CVG) remains unclear. We compared these 2 procedures with regard to early outcomes with propensity score matching using the Japan Cardiovascular Surgery Database.

METHODS

Of 5303 patients from the Japan Cardiovascular Surgery Database who had undergone aortic root replacement in 2008 to 2017, emergent/urgent or redo cases and those with infective endocarditis or aortic stenosis were excluded (included n = 3841). Two propensity score-matched groups treated with VSRR or CVG replacement (n = 1164 each) were established.

RESULTS

Overall, VSRR was more frequently performed for younger patients with Marfan syndrome with lower operative risk and aortic regurgitation grade compared with CVG replacement. After matching, a weaker but similar trend still existed in baseline characteristics. Although more concomitant procedures were performed in the CVG group, myocardial ischemia and cardiopulmonary bypass time was significantly longer in the VSRR group (median, 193 and 245 minutes) than the CVG group (172 and 223 minutes, both P < .01). The CVG group was associated with a significantly greater incidence of postoperative stroke (2.5% vs 1.1%, P = .01) and prolonged ventilation >72 hours (7.0% vs 4.6%, P = .02). In-hospital mortality rates were significantly greater in the CVG group (1.8%) than the VSRR group (0.8%, P = .02).

CONCLUSIONS

In overall Japanese institutions, VSRR was more frequently performed for patients at low risk and was associated with better morbidity and mortality rates than CVG replacement. After matching, VSRR was also associated with better morbidity and mortality rates despite longer procedure time.

Eighteen years of clinical experience with a modification of the Bentall button technique for total root replacement

Background

We retrospectively reviewed our experience with the modified Bentall procedure and evaluated the short- and long-term results over a period of 18 years.

Methods

Between 1999 and 2017, 89 patients with a mean age of 57.3±13.9 years underwent the modified Bentall operation with a slight modification for the correction of aortic root disease.

Results

The operative mortality was 1.1% while the overall early mortality rate, defined as death within 30 days of initial hospitalization, was 2.2% (2/89). Logistic regression analysis revealed that increased Euroscore and aortic cross-clamp times were associated with greater likelihood for complications. The overall survival rates for the 89 patients (including deaths occurred at the initial hospitalization) were 93.0% (SE =3.0%) at 6 months, 93.0% (SE =3.0%) at 1 year, 89% (SE =5.0%) at 5 years and 73.0% (SE =5.0%) at 10, 15 and 18 years. Multiple Cox regression analysis for survival identified that increased aortic cross-clamp time, increased age, having a concomitant cardiac procedure and increased NYHA Class were associated with greater hazard. Left ventricular remodeling was assessed by means of echocardiography preoperatively and 1, 3, 6 and 12 months postoperatively.

Conclusions

According to our experience, the Bentall procedure is a safe procedure, provides optimal long-term survival and can still be regarded as the gold standard procedure for aortic root replacement.

An Expansible Aortic Ring in Aortic Root Remodeling: Exact Position, Pulsatility, Effectiveness, and Stability in Three-Dimensional CT Study

BACKGROUND

The aim of this study was to assess effectiveness, stability, position, and expansibility of an expansible aortic annuloplasty ring with computed tomography (CT).

METHODS

Ten men (median age 51 years) scheduled for aortic root remodeling with implantation of external annuloplasty ring underwent contrast-enhanced CT of the aortic root preoperatively, postoperatively, and at a median of 21 months after operation. A reconstructed transverse double oblique view of the aortic base (AB) and of the new defined annuloplasty ring base (ARB; plane of the lower edge of the ring) in systole and diastole were obtained. The diameters, perimeter, and area were measured. In addition, the distances between AB and ARB in the nadir of each sinus were measured.

RESULTS

We found 12% reduction of the postoperative AB and 19% of ARB perimeter in both systole (p = 0.004, p < 0.001, respectively) and diastole (p = 0.001, p < 0.001, respectively) compared with preoperative. There was 22% reduction of the postoperative AB area in systole and 24% in diastole (p = 0.002, p = 0.001, respectively) and 33% reduction of the ARB area in systole and 32% in diastole (p < 0.001 for both) compared with the preoperative period. Nearly all measured variables in the follow-up period showed a slight increase compared with the postoperative period; however, they did not reach statistical significance. The postoperative systolic-diastolic differences in the three measured variables at the level of AB and ARB were statistically significant and were maintained throughout the follow-up period. The base of the ring was implanted 2 ± 2 mm at the right, 0 ± 1 mm at the left above the AB, and 2 (-3 to 2) mm at the noncoronary nadir below the AB.

CONCLUSIONS

This study demonstrates imaging evidence of the effectiveness, stability, and pulsatility of the annuloplasty ring in aortic root remodeling in follow-up and describes the exact position of the ring at the base of the aortic root.

A Bentall Is Not a Bentall Is Not a Bentall: The Evolution of Aortic Root Surgery

BACKGROUND

Aortic root pathology had been a known entity with a progressive and catastrophic course, long before the methods to surgically address them were first developed. Once reliable cardiopulmonary bypass was established, surgeons were able to pioneer new operative techniques, and in the half-century to follow, countless modifications and refinements have provided today's surgeons with the surgical approaches that are currently at their disposal.

HISTORY

Denton Cooley and Michael De Bakey reported the first successful surgical intervention for aneurysms involving the ascending aorta in 1956. Nearly a decade later, Hugh Bentall described his modification, and provided a name that would leave a lasting mark on aneurysmal surgery. In the decades to follow, numerous innovative surgeons improved on these original procedures to allow for a more reliable and consistent operation. Further, Tirone David and Sir Magdi Yacoub each described their methods to repair the aortic root while preserving the valve, thus providing their patients with freedom from a prosthetic or mechanical valve and improved quality of life.

CONCLUSIONS

The development of surgical techniques required to successfully care for patients with pathology of the aortic root has evolved considerably since Cooley and De Bakey's original report. Although it is common to hear aortic root replacement referred to as a "Bentall," the methods currently employed have gone through considerable evolution, such that the techniques of today should not be referred to as a Bentall.

Aortic valve sparing operations: a review

Aortic valve sparing operations were developed to preserve the native aortic valve during surgery for aortic root aneurysm as well as surgery for ascending aortic aneurysms with associated aortic insufficiency. There are basically two types of aortic valve sparing oprations: remodeling of the aortic root and reimplantation of the aortic valve. These operations have been performed for over two decades and the clinical outcomes have been excellent in experienced hands. Although remodeling of the aortic root is physiologically superior to reimplantation of the aortic valve, long-term follow-up suggests that the latter is associated with lower risk of developing aortic insufficiency. Failure of remodeling of the aortic root is often due to dilatation of the aortic annulus. Thus, this type of aortic valve sparing should be reserved for older patients with ascending aortic aneurysm and normal aortic annulus whereas reimplantation of the aortic valve is more appropriate for young patients with inherited disorders that cause aortic root aneurysms. This article summarizes the published experience with these two operations. They are no longer experimental procedures and should be part of the surgical armamentarium to treat patients with aortic root aneurysm and ascending aortic aneurysms with associated aortic insufficiency.