Aortic Root Dynamics Research Articles

Aortic Root Surgery in Adults: An Unsolved Problem

Nowadays, despite the rapid advancements in interventional cardiology, open surgery still deals with aortic root diseases, to assure the best "ad hoc" treatment. In case of middle-aged adult patients, the optimal operation still represents a matter of debate. A review of the last 10-year literature was conducted, focusing on patients below 65 to 70 years of age. Because of the small sample and the heterogeneity of the papers, no metanalysis was possible. Bentall-de Bono procedure, valve sparing, and Ross operations are the surgical options currently available. The main issues in the Bentall - de Bono operation are lifelong anticoagulation therapy and cavitation in case of mechanical prosthesis implantation and structural valve degeneration in case of biological Bentall. As transcatheter procedures are currently performed as valve in valve, biological prosthesis may be preferable, if the diameter may prevent postoperative high gradients. Conservative techniques, such as remodeling and reimplantation, preferred in the young, guarantee physiologic aortic root dynamics and impose surgical analysis of the aortic root structures to get a durable result. The Ross operation, which shows excellent performance, involves autologous pulmonary valve implantation and is performed only in experienced and high-volume centers. Due to its technical difficulty, it requires a steep learning curve and presents some limitations in specific aortic valve diseases. All three have advantages and downsides, and no ideal solution has still been reported.

Changes in aortic root dimensions after ascending aortic repair with concomitant aortic valve replacement

The issue of ascending aortic repair with concomitant aortic valve replacement in pa-tients with ascending aortic aneurysm (AscAA) and aortic valve stenosis is still debatable.Aim. To analyze the dimension changes of the preserved aortic root after simultaneous ascending aorta repair and aortic valve replacement.Material and methods. This retrospective study included 102 patients who, from December 2012 to May 2022, underwent simultaneous aortic valve replacement and ascending aorta repair with hemiarch replacement. Patients were divided into 2 following groups based on the aortic valve morphology: group 1 — patients with bicuspid aortic valve (BAV) and AscAA (n=75), group 2 — patients with tricuspid aortic valve (TAV) and AscAA (n=27). Depending on the presence of aortic root dilatation (maximum diameter (d) >40 mm), each of the groups was additionally stratified into 2 more subgroups as follows: patients without aortic root dilatation (d≤40 mm) and patients with its dilatation (d>40 mm). The dynamics of the aortic root diameter was assessed by computed tomography angiography.Results. The mean follow-up period for patients was 36,2±14,6 months. Survival rate in the BAV+AscAA and TAV+AscAA groups was 96% and 100%, respectively (p=0,380). Freedom from aortic root resurgery was 100% in both study groups. In patients with dilated and non-dilated aortic root of the BAV+AscAA group, an increase in aortic root dimension was noted at a rate of 0,65±0,51 mm/year and 0,32±0,27 mm/year, respectively. In patients of the TAV+AscAA group, a regression in dilated and non-dilated aortic root diameter was observed as follows: 0,93±0,48 mm/year and 0,56±0,43 mm/year, respectively.Conclusion. In patients with AscAA in combination with BAV stenosis after a singlestep surgical intervention, a weak negative dynamics of non-dilated and dilated aortic root is observed in the mid-term follow-up period. In patients with AscAA and TAV, there is involutive alterations of the aortic root dimension during 3-year follow-up.

Dynamic Volumetric Assessment of the Aortic Root: The Influence of Bicuspid Aortic Valve Competence

Aortic root evaluation is conventionally based on 2-dimensional measurements at a single phase of the cardiac cycle. This work presents an image analysis method for assessing dynamic 3-dimensional changes in the aortic root of minimally calcified bicuspid aortic valves (BAVs) with and without moderate to severe aortic regurgitation. The aortic root was segmented over the full cardiac cycle in 3-dimensional transesophageal echocardiographic images acquired from 19 patients with minimally calcified BAVs and from 16 patients with physiologically normal tricuspid aortic valves (TAVs). The size and dynamics of the aortic root were assessed using the following image-derived measurements: absolute mean root volume and mean area at the level of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction, as well as normalized root volume change and normalized area change of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction over the cardiac cycle. Normalized volume change over the cardiac cycle was significantly greater in BAV roots with moderate to severe regurgitation than in normal TAV roots and in BAV roots with no or mild regurgitation. Aortic root dynamics were most significantly different at the mid-level of the sinuses of Valsalva in BAVs with moderate to severe regurgitation than in competent TAVs and BAVs. Echocardiographic reconstruction of the aortic root demonstrates significant differences in dynamics of BAV roots with moderate to severe regurgitation relative to physiologically normal TAVs and competent BAVs. This finding may have implications for risk of future dilatation, dissection, or rupture, which warrant further investigation.

Aortic Root Dynamics in Sleeve Aortic Sparing Procedure: Echocardiographic and Computational Studies

In Sleeve procedure, the leaflets-sinus unit is maintained. We hypothesized that this feature partially preserves aortic root (AR) dynamics and leaflets kinematics and limits tensions in the leaflets. We tested our hypothesis based on in vivo and computational assessment of leaflets and AR dynamics. AR and aortic leaflet kinematics was assessed by transthoracic echocardiography in 10 patients treated with the Sleeve procedure and in 10 healthy patients. Numerical calculations with the Finite Element Method were performed to support the analysis of the clinical results and provide a better understanding of the behavior of the AR treated via the Sleeve procedure. Echocardiographic evidence showed that AR expansion in the Sleeve group was partially preserved as compared to the Control group (2.9 ± 2.5% vs 7.7 ± 6.3%, P = 0.038) and of the sinotubular junction (2.9 ± 1.5% vs 7.3 ± 3.8%, P = 0.003), and significantly preserved at the Valsalva sinuses level (6.7 ± 2.6% vs 9.5 ± 4.3%) with not statistically significant differences (P = 0.11). In none of the cardiac phases, differences in aortic valve leaflets kinematics were measured between the 2 groups; computational results were rather consistent with this evidence. Computational results well matched echocardiographic evidences, allowing for their mechanistic interpretation. Near-normal opening and closing characteristics can be accomplished by a technique that preserves the shape and the dynamics of the Valsalva sinuses. Whether the substantial preservation of the AR distensibility and leaflets kinematics observed in this study will favorably affect long-term valve durability it remains to be ascertained.

Aortic valve opening and closure: the clover dynamics.

Systolic aortic root expansion is reported to facilitate valve opening, but the precise dynamics remain unknown. A sonometric study with a high data sampling rate (200 to 800 Hz) was conducted in an acute ovine model to better understand the timing, mechanisms, and shape of aortic valve opening and closure. Eighteen piezoelectric crystals were implanted in 8 sheep at each annular base, commissures, sinus of Valsalva, sinotubular junction, nodulus of Arantius, and ascending aorta (AA). Geometric changes were time related to pressures and flows. The aortic root was hemodynamically divided into left ventricular (LV) and aortic compartments situated, respectively, below and above the leaflets. During isovolumetric contraction (IVC), aortic root expansion started in the LV compartment, most likely due to volume redistribution in the LV outflow tract below the leaflets. This expansion initiated leaflet separation prior to ejection (2.1%±0.5% of total opening area). Aortic compartment expansion was delayed toward the end of IVC, likely related to volume redistribution above the leaflets due to accelerating aortic backflow toward the aortic valve and coronary flow reduction due to myocardial contraction. Maximum valve opening during the first third of ejection acquired a truncated cone shape [leaflet free edge area smaller than annular base area (-41.5%±5.5%)]. The distal orifice became clover shaped because the leaflet free edge area is larger than the commissural area by 16.3%±2.0%. Aortic valve opening is initiated prior to ejection related to delicate balance between LV, aortic root, and coronary dynamics. It is clover shaped at maximum opening in systole. A better understanding of these mechanisms should stimulate more physiological surgical approaches of valve repair and replacement.

A novel approach to the quantification of aortic root in vivo structural mechanics.

Understanding aortic root in vivo biomechanics can help in elucidating key mechanisms involved in aortic root pathologies and in the outcome of their surgical treatment. Numerical models can provide useful quantitative information. For this to be reliable, detailed aortic root anatomy should be captured. Also, since the aortic root is never unloaded throughout the cardiac cycle, the modeled geometry should be consistent with the in vivo loads acting on it. Achieving such consistency is still a challenge, which was tackled only by few numerical studies. Here we propose and describe in detail a new approach to the finite element modeling of aortic root in vivo structural mechanics. Our approach exploits the anatomical information yielded by magnetic resonance imaging by reconstructing the 3-dimensional end-diastolic geometry of the aortic root and makes the reconstructed geometry consistent with end-diastolic loading conditions through the estimation of the corresponding prestresses field. We implemented our approach through a semiautomated modeling pipeline, and we applied it to quantify aortic root biomechanics in 4 healthy participants. Computed results highlighted that including prestresses into the model allowed for pressurizing the aortic root to the end-diastolic pressure while matching the image-based ground truth data. Aortic root dynamics, tissues strains, and stresses computed at relevant time points through the cardiac cycle were consistent with a broad set of data from previous computational and in vivo studies, strongly suggesting the potential of the method. Also, results highlighted the major role played by the anatomy in driving aortic root biomechanics.

The Ross procedure: total root technique.

We describe our technique for the Ross procedure using a total root technique without any foreign material for autograft support. We insist on technical principles, based on the surgical anatomy of the aortic and pulmonary root, aimed at optimizing aortic root dynamics while ensuring long-term stability of the autograft root.

An expansible aortic ring to preserve aortic root dynamics after aortic valve repair†

Aortic annuloplasty and preservation of root dynamics have been described as factors for durability of aortic valve repair. The objective of this study is to document the first clinical analysis of root dynamics after a standardized valve-sparing procedure for root aneurysms associating a calibrated expansible external aortic ring annuloplasty with a physiological remodelling of the aortic root (CAVIAAR technique: Conservative Aortic Valve surgery for aortic Insufficiency and Aneurysm of the Aortic Root). Of the 600 patients operated on with the CAVIAAR technique, 60 consecutive patients from a single team underwent double independent reading of the echocardiographic analysis performed in the operative period and yearly after discharge until a maximum of 5-year follow-up. Forty-four patients had preoperative aortic insufficiency (AI) ≥grade 2 (73.3%) and 29 patients (48%) had bicuspid valves. The expansible aortic ring (median size 27 (25-27) mm) significantly reduced the aortic annular base diameter (from 28 (25-29) mm to 23 (21-24) mm) (P < 0.001) without a significant median transvalvular gradient increase (P = 0.545). Cusp repair was performed in 55 patients (91.7%). Operative mortality was 1.7% (1). During the median 19-month (95% confidential interval [11-26]) follow-up, annular diameter and cusp effective height remained stable. There were no valve-related reoperations. One patient died at 6 months postoperatively from congestive heart failure. Freedom from AI ≥grade 2 was 100% at 1-year follow-up and 96.8% ± 3.2% at 3-year follow-up. Systolic root expansibility of the four echocardiographic diameters (aortic annular base, sinuses of Valsalva level, sino tubular junction and tubular aorta) was maintained, throughout the follow-up period with the aortic annular base expansibility coefficient having consistently higher values than the three other levels. The expansible aortic ring achieved a complete calibrated external annuloplasty and maintained dynamics of the aortic root at mid-term follow-up. Whether this could be a factor for durability of aortic valve repair is currently under evaluation through the CAVIAAR study 10-year follow-up.

Valve sparing root replacement: the remodeling technique with external ring annuloplasty.

A standardized approach to aortic valve repair is described associating a physiological remodeling of the root, with resuspension of cusp effective height and a subvalvular aortic annuloplasty using an external expansible ring. This device achieves a complete calibrated annuloplasty, in order to increase cups coaptation height and protect the repair. This is a video-atlas describing the surgical steps of a physiological and standardized approach to aortic valve repair, to treat an aortic root aneurysm associated with grade III to IV eccentric aortic insufficiency on a 41-year old patient with a tricuspid aortic valve (Video 1). Ideal valve sparing root replacement procedure should treat dilatation of the aortic annular base, while preserving dynamics of the aortic root with vortices (neosinuses of Valsalva), root expansibility (interleaflet triangles) as well as restoring cusp coaptation (1-5). Video 1 Valve sparing root replacement: the remodeling technique with external ring annuloplasty The two original valve sparing procedures - remodeling of the aortic root and reimplantation of the aortic valve - focused on root reconstruction to reduce the dilated root diameters in order to restore proper valve function (6,7). The reimplantation technique performs external subvalvular aortic annuloplasty but withdraws the sinuses of Valsalva and includes the interleaflet triangles within a graft tube, thus impairing root dynamics (8-11). In contrast, the remodeling technique provides more physiologic movements of the cusps within three reconstructed neo-sinuses, thus preserving root expansibility through the interleaflet triangles, but without addressing annular base dilation (8-13). In vitro and in vivo studies have documented that cusp motion and flow patterns across the reconstructed aortic root are more physiologic (I) after remodeling of the aortic root than after reimplantation of the aortic valve, and (II) after procedures using a prosthetic conduit fashioned with neo- sinuses of Valsalva than without (9-11). Numerous technical variations have aimed to associate preservation of aortic root dynamics with the treatment of dilated native annulus (14,15). This resulted in a lack of standardization and limited their widespread application. Furthermore, most failures with valve sparing techniques are due to residual cusp prolapse, either as a primary unrecognized lesion or secondary to an induced prolapse after root reconstruction (12,16). Schafers et al. proposed to address this issue with a dedicated caliper in order to restore cusp effective height up to 8-10 mm (1,4,12). Therefore we suggest a standardized approach of aortic valve repair addressing both the aorta and the valve, associating a physiological reconstruction of the aortic root according to the remodeling technique, with resuspension of cusp effective height and an expansible subvalvular ring annuloplasty (CAVIAAR technique) (Figure 1) (2,17-19). Figure 1 Remodeling of the aortic root associated to an external subvalvular aortic annuloplasty (CAVIAAR technique), combining advantages of the original remodeling and reimplantation techniques To address the need for a dedicated aortic annuloplasty device, we designed a new expansible aortic ring in order to achieve a complete and calibrated annuloplasty in diastole, while maintaining systolic expansibility of the aortic root (Extra-Aortic™, CORONEO, Inc., Montreal, QC, Canada) (19). As such, cusp coaptation height is increased, reducing stress on the cusps and protecting the repair.

Usefulness of real-time three-dimensional echocardiography in evaluating aortic root diameters during a cardiac cycle.

The preoperative evaluation of aortic root diameters is important for determining the surgical strategy in patients with aortic valve disease. The purpose of this study was to evaluate the usefulness of real-time three-dimensional echocardiography (3D-echo) for the evaluation of aortic root diameters compared with two-dimensional echocardiography (2D-echo) and to evaluate aortic root dynamics. We prospectively investigated 23 patients with aortic stenosis (AS) and 37 normal controls. With 2D-echo, aortic root diameters were measured from the parasternal long-axis view. With 3D-echo, long-axis and short-axis views of the aortic root were reconstructed from the full-volume image, and aortic root diameters were measured at mid-systole, end-systole, mid-diastole, and end-diastole. These aortic root diameters were compared between 2D and 3D measurements, regarding intraoperative and computed tomographic measurements as the gold standard. In addition, dynamic changes of aortic root diameters during a cardiac cycle were evaluated. Aortic root diameters measured by 3D-echo were larger than those measured by 2D-echo (annular diameter 19.6±2.1 vs. 21.2±2.2mm, p<0.0001), and 3D measurements were closer to intraoperative and computed tomographic measurements than 2D measurements. The diameter of the aortic annulus increased during diastole, but the changes during a cardiac cycle were significantly smaller in patients with AS than in normal controls (2.0±2.2 vs. 7.8±3.4%, p<0.0001). Aortic root diameters can be more accurately measured by 3D-echo than 2D-echo. Dynamic change of the aortic annulus during a cardiac cycle was smaller in patients with AS. 3D-echo is useful for the quantitative evaluation of the aortic root, including dynamics during a cardiac cycle.

Remodeling of the aortic root combined to an expansible aortic ring annuloplasty

Aortic root aneurysms are characterized by dilation of both functional aortic annulus diameters (aortic annular base and sino-tubular junction), preventing coaptation of otherwise pliable valves often associated with cusp prolapse. Multiple techniques of aortic valve sparing procedures try to restore the complex interplay of aortic valve and root function in order to improve durability of the repair. Ideally, procedures should treat dilatation of the aortic annular base, while preserving dynamics of the aortic root with vortices (neosinuses of Valsalva) and root expansibility (interleaflet triangles). We describe a standardized approach, combining the advantages of both the remodeling and reimplantation technique by adding an external subvalvular ring annuloplasty to the physiological remodeling of the aortic root. To address the need for a dedicated aortic annuloplasty device, a new expansible aortic ring was designed in order to achieve a complete and calibrated annuloplasty in diastole, while maintaining systolic expansibility of the aortic root.

Clinical evaluation of the biophysio aortic bioprosthesis

Aims: The BioPhysio (Edwards Lifesciences LLC, Irvine, CA) bioprosthesis was designed to further improve hemodynamic performance currently achieved by stented valves. A flexible nitinol stent that preserves aortic root dynamics, thus maximizing effective orifice area, is a key innovation of this prosthesis.

Variability of aortic root geometry before and after aortic valve replacement with pericardial supraannular stentless valve prosthesis

Objectives: Recent experimental studies showed that the aortic root undergoes complex deformations during the cardiac cycle, which probably minimize aortic cusp stress and aortic valve degeneration. We want to show that aortic valve replacement (AVR) techniques can restore this normal pattern of aortic root dynamics.

Aortic root dynamics and surgery: from craft to science

Since the fifteenth century beginning with Leonardo da Vinci's studies, the precise structure and functional dynamics of the aortic root throughout the cardiac cycle continues to elude investigators. The last five decades of experimental work have contributed substantially to our current understanding of aortic root dynamics. In this article, we review and summarize the relevant structural analyses, using radiopaque markers and sonomicrometric crystals, concerning aortic root three-dimensional deformations and describe aortic root dynamics in detail throughout the cardiac cycle. We then compare data between different studies and discuss the mechanisms responsible for the modes of aortic root deformation, including the haemodynamics, anatomical and temporal determinants of those deformations. These modes of aortic root deformation are closely coupled to maximize ejection, optimize transvalvular ejection haemodynamics and-perhaps most importantly-reduce stress on the aortic valve cusps by optimal diastolic load sharing and minimizing transvalvular turbulence throughout the cardiac cycle. This more comprehensive understanding of aortic root mechanics and physiology will contribute to improved medical and surgical treatment methods, enhanced therapeutic decision making and better post-intervention care of patients. With a better understanding of aortic root physiology, future research on aortic valve repair and replacement should take into account the integrated structural and functional asymmetry of aortic root dynamics to minimize stress on the aortic cusps in order to prevent premature structural valve deterioration.

691 Intracardiac echocardiography for conservative aortic valve surgery: A new investigative tool

Background: Dilation of aortic annulus and sino-tubulaire junction (STJ) is a characteristic lesion of dystrophic aortic insufficiency. A standardized approach of conservative aortic valve surgery has been suggested using external expansible aortic ring. Intracardiac Echocardiography (ICE) was used to study aortic root dynamics before and after conservative aortic valve surgery on an ovine model. Methods: Six sheeps underwent a double sub and supravalvular annuloplasty, performed by the implantation of 2 expansible rings, at the level of the aortic annular base (22 mm ring) and sino-tubular junction (STJ, 18 mm ring). Imageswere obtained using ICE (AcuNav®, Siemens) with high resolution probe (5 to 10 MHz), introduced through the left internal jugular vein into the right atrium. Coaptation height and expansion of the aortic root were studied. Results: Aortic root parameters were analyzed before (B) and after (A) the implantation of the expansible prosthetic rings (table 1), which produced significant reduction of annulus and STJ diameters, respectively -36.5% and -33.9%, without significant gradient. ICE allowed good visualization of valvular coaptation, with a mean coaptation height of 0.27±0.07 cm pre-implantation and 0.46±0.07 cm after implantation (p<0.001). Conclusion: Implantation of expansible aortic ring prosthetic ring reduces aortic annulus and STJ diameters, increases leaflet coaptation area while preserving aortic root expansibility. ICE provided a precise analysis of aortic root dynamics in an ovine model. It might be an interesting tool to assess the properties of the aortic root after valve repair for dystrophic aortic insufficiency

Aortic prosthetic ring annuloplasty: a useful adjunct to a standardized aortic valve-sparing procedure?☆

Dilation of aortic annulus, sinuses of Valsalva, and sinotubular junction (STJ) diameters are the characteristic lesions of aortic root aneurysm. The remodeling technique reduces STJ diameter and creates three neosinuses of Valsalva. Alternatively, the reimplantation technique reduces both annulus and STJ diameters to the detriment of aortic root dynamics. Although the remodeling technique is recognized as the most physiological valve-sparing procedure, aortic annulus dilation may jeopardize its results. A standardized approach that combines an external subvalvular aortic prosthetic ring annuloplasty with the remodeling technique is suggested. Eighty-three patients underwent an elective aortic root remodeling procedure, either isolated (group 1, n=34) or combined with an external subvalvular aortic prosthetic ring annuloplasty (group 2, n=49). Preoperative aortic regurgitation was 1.59+/-1.1 (group 1) and 1.97+/-1.3 (group 2) (NS). The aortic annulus was more dilated in group 2 than in group 1 (27+/-2.77 mm vs 26.4+/-2.3 mm, p<0.01). Residual aortic regurgitation > or =grade II was the conversion criteria for aortic valve replacement. Operative mortality was 3.6% (n=3). Intraoperative conversion for valve replacement was 32.7% in group 1 (n=11) versus 4.2% in group 2 (n=2) (p<0.001). In group 1, preoperative annulus diameter was larger for converted than for valve-spared patients (27.6+/-1.7 mm vs 25.2+/-1.5 mm, p<0.02). In group 2, implanted aortic ring significantly reduced annulus diameter (20.6+/-1.8 mm) without significant aortic valve gradient (8.3+/-3 mmHg). Follow-up was 17.2+/-13.4 months (group 1) and 10.41+/-7.95 months (group 2). Reoperation for recurrent aortic regurgitation was 13% in group 1 (n=3) versus 4.2% in group 2 (n=2). Echocardiographic follow-up found residual aortic regurgitation < or =grade I in 17 patients in group 1 (90%) versus 43 patients in group 2 (95.5%) and of grade II in two patients in group 1 (10%) and two patients in group 2 (4.5%). The addition of external aortic prosthetic ring annuloplasty improves the remodeling technique's operative reproducibility and short-term results. Therefore, its use as a systematical adjunct to the remodeling procedure is suggested. However, further long-term evaluation comparing this valve-sparing procedure to composite graft replacement should define the best surgical strategy for aortic root aneurysm.

A four-dimensional study of the aortic root dynamics.

Although aortic root expansion has been well studied, its deformation and physiologic relevance remain controversial. Three-dimensional (3-D) sonomicrometry (200Hz) has made time-related 4-D study possible. Fifteen sonomicrometric crystals were implanted into the aortic root of eight sheep at each base (three), commissures (three), sinuses of Valsalva (three), sinotubular junction (three), and ascending aorta (three). In this acute, open-chest model, the aortic root geometric deformations were time related to left ventricular and aortic pressures. During the cardiac cycle, aortic root volume increased by mean+/-1 standard error of the mean (SEM) 33.7+/-2.7%, with 36.7+/-3.3% occurring prior to ejection. Expansion started during isovolumic contraction at the base and commissures followed (after a delay) by the sinotubular junction. At the same time, ascending aorta area decreased (-2.6+/-0.4%). During the first third of ejection, the aortic root reached maximal expansion followed by a slow, then late rapid decrease in volume until mid-diastole. During end-diastole, the aortic root volume re-expanded by 11.3+/-2.4%, but with different dynamics at each area level. Although the base and commissural areas re-expanded, the sinotubular junction and ascending aorta areas kept decreasing. At end-diastole, the aortic root had a truncated cone shape (base area>commissures area by 51.6+/-2.0%). During systole, the root became more cylindrical (base area>commissures area by 39.2+/-2.5%) because most of the significant changes occurred at commissural level (63.7+/-3.6%). Aortic root expansion follows a precise chronology during systole and becomes more cylindrical - probably to maximize ejection. These findings might stimulate a more physiologic approach to aortic valve and aortic root surgical procedures.

Deformational Dynamics of the Aortic Root

Background —Current surgical methods for treating aortic valve and aortic root pathology vary widely, and the basis for selecting one repair or replacement alternative over another continues to evolve. More precise knowledge of the interaction between normal aortic root dynamics and aortic valve mechanics may clarify the implications of various surgical procedures on long-term valve function and durability. Methods and Results —To investigate the role of aortic root dynamics on valve function, we studied the deformation modes of the left, right, and noncoronary aortic root regions during isovolumic contraction, ejection, isovolumic relaxation, and diastole. Radiopaque markers were implanted at the top of the 3 commissures (sinotubular ridge) and at the annular base of the 3 sinuses in 6 adult sheep. After a 1-week recovery, ECG and left ventricular and aortic pressures were recorded in conscious, sedated animals, and the 3D marker coordinates were computed from biplane videofluorograms (60 Hz). Left ventricular preload, contractility, and afterload were independently manipulated to assess the effects of changing hemodynamics on aortic root 3D dynamic deformation. The ovine aortic root undergoes complex, asymmetric deformations during the various phases of the cardiac cycle, including aortoventricular and sinotubular junction strain and aortic root elongation, compression, shear, and torsional deformation. These deformations were not homogeneous among the left, right, and noncoronary regions. Furthermore, changes in left ventricular volume, pressure, and contractility affected the degree of deformation in a nonuniform manner in the 3 regions studied, and these effects varied during isovolumic contraction, ejection, isovolumic relaxation, and diastole. Conclusions —These complex 3D aortic root deformations probably minimize aortic cusp stresses by creating optimal cusp loading conditions and minimizing transvalvular turbulence. Aortic valve repair techniques or methods of replacement using unstented autograft, allograft, or xenograft tissue valves that best preserve this normal pattern of aortic root dynamics should translate into a lower risk of long-term cusp deterioration.

Deformational dynamics of the aortic root: modes and physiologic determinants.

Current surgical methods for treating aortic valve and aortic root pathology vary widely, and the basis for selecting one repair or replacement alternative over another continues to evolve. More precise knowledge of the interaction between normal aortic root dynamics and aortic valve mechanics may clarify the implications of various surgical procedures on long-term valve function and durability. To investigate the role of aortic root dynamics on valve function, we studied the deformation modes of the left, right, and noncoronary aortic root regions during isovolumic contraction, ejection, isovolumic relaxation, and diastole. Radiopaque markers were implanted at the top of the 3 commissures (sinotubular ridge) and at the annular base of the 3 sinuses in 6 adult sheep. After a 1-week recovery, ECG and left ventricular and aortic pressures were recorded in conscious, sedated animals, and the 3D marker coordinates were computed from biplane videofluorograms (60 Hz). Left ventricular preload, contractility, and afterload were independently manipulated to assess the effects of changing hemodynamics on aortic root 3D dynamic deformation. The ovine aortic root undergoes complex, asymmetric deformations during the various phases of the cardiac cycle, including aortoventricular and sinotubular junction strain and aortic root elongation, compression, shear, and torsional deformation. These deformations were not homogeneous among the left, right, and noncoronary regions. Furthermore, changes in left ventricular volume, pressure, and contractility affected the degree of deformation in a nonuniform manner in the 3 regions studied, and these effects varied during isovolumic contraction, ejection, isovolumic relaxation, and diastole. These complex 3D aortic root deformations probably minimize aortic cusp stresses by creating optimal cusp loading conditions and minimizing transvalvular turbulence. Aortic valve repair techniques or methods of replacement using unstented autograft, allograft, or xenograft tissue valves that best preserve this normal pattern of aortic root dynamics should translate into a lower risk of long-term cusp deterioration.