Does dilatation of the sinotubular junction cause aortic regurgitation?

Ross Operation with Autologous External Autograft Stabilization - Long-term Results

BACKGROUND

We have proposed an external stabilization technique to minimize autograft dilatation after the Ross operation. The aim of this study was to analyze autograft function and root dimensions following root replacement with and without external root support.

METHODS

Between 10/1995 and 02/2021, 185 adult patients (73% male; age 38±9 years) underwent a Ross operation as full-root replacement with (n=136) or without support (n=49). Autograft function and root dimensions were determined echocardiographically. Median follow-up was 3.4[1.13-14.74] years; it was 95% complete. Survival and freedom from reoperation were calculated; changes in autograft root dimensions were analyzed using mixed-effect models.

RESULTS

Survival (95%) and freedom from autograft reoperation (94%) at 15 years were higher with than without support (p=0.003 or p=0.004). In the first five years, patients with support showed an indexed root size progression of 0.712mm/(year*m)(p=0.003) compared to 1.554mm/(year*m)(p=0.001) without. Progression rates were higher for patients without stabilization (p=0.045). After five years, progression rates were similar in both groups (0.248mm/(year*m)(p<0.001) with persistent difference between the groups.

CONCLUSIONS

The Ross procedure as full-root replacement is associated with a relevant rate of autograft dilatation and reoperation. The use of external root stabilization may reduce autograft dilatation and is associated with improved survival and durability.

Predictors of Bicuspid Aortic Valve–Associated Aortopathy in Childhood

Background:

Bicuspid aortic valve (BAV) is the most prevalent congenital heart defect affecting 1% to 2% of the population. It is associated with ascending aorta dilatation. Valve morphology, aortic stenosis (AS), and aortic insufficiency (AI) have been proposed as potential risk factors; however, evaluating their role is difficult, as these factors are inherently related. The aim of this study was to determine whether BAV morphology and dysfunction are independent determinants for ascending aorta dilatation in pediatric patients.

Methods:

A multicenter, retrospective, cross-sectional study of pediatric BAV patients followed since 2004 was performed. Imaging data were assessed for BAV morphology, severity of AS and AI, history of coarctation, and aortic dimensions. Associations were determined using multivariable regression analysis. A subset of patients undergoing aortic interventions (balloon dilation or Ross) were assessed longitudinally.

Results:

Data were obtained from 2122 patients (68% male; median age 10.2 years). Fifty percent of patients had ascending aorta dilatation. Right and noncoronary cusp fusion, increasing AS and AI, and older age were independently associated with ascending aorta dilatation. A history of coarctation was associated with less ascending aorta dilatation. In patients with neither AS nor AI, 37% had ascending aorta dilatation (4% severe). No complications related to aortic dilatation occurred in this cohort. Aortic Z scores were determined, and a Z -score calculator was created for this population.

Conclusions:

In this large pediatric cohort of patients with BAV, valve morphology, AS, and AI are independently associated with ascending aorta dilatation, suggesting that hemodynamic factors influence aortopathy. However, even in BAVs with no AS or AI, there is significant ascending aorta dilatation independent of valve morphology. Interventions that led to changes in degree of AI and AS did not seem to influence change in aortic dimensions. The current BAV cohort can be used as a reference group for expected changes in aortic dimensions during childhood.

Neoaortic Regurgitation in Patients with Transposition Long Term After an Arterial Switch Operation and Its Relation to the Root Diameters and Surgical Technique Used

Neoaortic regurgitation and root dilatation are common findings in patients with transposition after an arterial switch operation. The aim of this study was to describe the relation between neoaortic regurgitation long term after an arterial switch procedure, aortic root diameters, and surgical technique used. We also assessed the agreement of the neoaortic regurgitation grade and root diameters in different imaging modalities. For this retrospective study, we qualified 56 consecutive patients who, according to our institutional protocol, had a routine postoperative evaluation of more than 16 years with multimodality imaging studies. Neoaortic regurgitation was assessed by both transthoracic echocardiography and magnetic resonance imaging, and the root diameters obtained by echocardiography and tomography were compared to the reference values and associated with the presence of neoaortic insufficiency. Neoaortic insufficiency was present in 75% of examined patients; the vast majority of them had trace or mild regurgitation, and its qualitative evaluation was significantly different between echocardiography and magnetic resonance imaging. In our study group, the neoaortic valve and aortic sinus were larger in relation to the normal values, and they were significantly correlated with the presence of neoaortic insufficiency, but not with the surgical technique used. Values obtained by echocardiography and tomography correlated well but were significantly different. Transthoracic echocardiography has a tendency to overestimate the severity of regurgitation compared to magnetic resonance imaging. Neoaortic valve and sinus dilatation are significantly correlated with valve insufficiency, but in most cases of root dilatation, the valve remains competent.

Commissure enhancement technique in aortic valve repair

Sinotubular junction enlargement is one of possible causes of aortic valve regurgitation. However, there is no appropriate technique for sinotubular junction diameter reduction in aortic valve repair in a patient without disease of the ascending aorta or sinus of Valsalva. Herein, we report a simple commissure enhancement technique comprising the placement a horizontal mattress suture buttressed with felt at the sinotubular junction level in the commissure area. This technique results in the relocation of the commissure to the inner side, and a reduction in the diameter of the sinotubular junction.

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.

Patients with calcific aortic stenosis exhibit systemic molecular evidence of ischemia, enhanced coagulation, oxidative stress and impaired cholesterol transport

BACKGROUND

The most common valve diseases are calcific aortic stenosis (AS) and aortic regurgitation (AR). The former is characterized by thickening of valve leaflets followed by progressive calcification, which produces progressive aortic valve (AV) narrowing, increased pressure afterload on the left ventricle (LV) and subsequent LV hypertrophy. On the other hand, AR is due to malcoaptation of the valve leaflets with resultant diastolic reflux of blood from aorta back to the LV producing volume and pressure overload and progressive LV dilatation. In order to isolate the molecular mechanisms taking place during AS, we have used an integrated "-omic" approach to compare plasma samples from AS and from AR patients used as controls. The final purpose of this work is to find molecular changes in response to the calcification of the AV, diminishing the effects of the AV dysfunction.

METHODS AND RESULTS

Using two-dimensional difference gel electrophoresis (2D-DIGE) and gas chromatography coupled to mass spectrometry (GC-MS) in a cohort of 6 subjects, we have found differences in 24 protein spots and 19 metabolites, respectively. Among them, 7 proteins and 3 metabolites have been verificated by orthogonal techniques (SRM or turbidimetry): fibrinogen beta and gamma chain, vitronectin, apolipoprotein C-II, antithrombin III, haptoglobin, succinic acid, pyroglutamic acid and alanine. Classification according to their main function showed alterations related to coagulation, inflammation, oxidative stress, response to ischemia and lipid metabolism, defining 4 different molecular panels that characterize AS with high specificity and sensitivity.

CONCLUSION

These results may facilitate management of these patients by making faster diagnostics of the disease and better understand these pathways for regulating its progression.

Pathobiology of Idiopathic Ascending Aortic Aneurysms

The majority of ascending aortic aneurysms cannot be related to any specific etiology and should be qualified as idiopathic. The pathobiology of ascending aortic aneurysms remains incompletely understood. Data from direct study are still scarce and often limited because of patient heterogenicity. Currently available information suggests that destructive remodeling of the aortic wall, inflammation and angiogenesis, biomechanical wall stress, and molecular genetics are relevant mechanisms of idiopathic ascending aortic aneurysm formation and progression. Further understanding of these mechanisms will likely provide novel diagnostic, prognostic, and therapeutical tools for the clinician.

Management of aortic insufficiency in the continuous flow left ventricular assist device population

With the current generation of continuous-flow (CF) left ventricular assist devices (LVADs), patients are able to be supported for longer periods of time. As a result, there has been increasing focus on long-term complications from prolonged mechanical circulatory support, such as acquired aortic insufficiency (AI). In the presence of an LVAD, AI leads to a blind circulatory loop, with a portion of LVAD output regurgitating through the aortic valve (AV) into the left ventricle and back again through the device, limiting effective forward flow and ultimately leading to organ malperfusion and increased left ventricular diastolic pressures. The AV also experiences abnormal biomechanics as a result of limited valve opening in the presence of a CF LVAD. Increased shear stress, elevated transvalvular pressure gradients, and decreased valve open time all contribute to acquired AI. The prognosis of moderate to severe AI in LVAD patients is generally poor and leads to a higher rate of AV replacement and potentially reduced survival. However, there are no evidence-based guidelines for management of this challenging population. In severe AI, experts generally advocate AV replacement or repair, while lesser degrees of AI can be managed medically and/or with adjustments in pump parameters.

The role of transesophageal echocardiography in aortic valve preserving procedures

In selected cases of aortic regurgitation, aortic valve (AV) repair and AV sparing root reconstruction viable alternatives to aortic valve replacement. Repair and preservation of the native valve avoids the use of long-term anticoagulation, lowers the incidence of subsequent thromboembolic events and reduces the risk of endocarditis. Additionally repair has a low operative mortality with reasonable mid-term durability. The success and longer term durability of AVPP has improved with surgical experience. An understanding of the mechanism of the AR is integral to determining feasibility and success of an AVPP. Assessment of AV morphology, anatomy of the functional aortic annulus (FAA) and the aortic root with transesophageal echocardiography (TEE) improves the understanding of the mechanisms of AR. Pre- and intra-operative TEE plays a pivotal role in guiding case selection, surgical planning, and in evaluating procedural success. Post-operative transthoracic echocardiography is useful to determine long-term success and monitor for recurrence of AR.

Supravalvar aortic stenosis: current surgical approaches and outcomes

Supravalvar aortic stenosis (SVAS) is a congenital anomaly characterized by a discrete or diffuse narrowing of the ascending aorta. It may also be associated with right-ventricular outflow tract obstruction, aortic valve pathology and coronary ostial stenosis. While present in both familial and sporadic forms, it demonstrates a strong association with William-Beuren syndrome, both being anomalies associated with defects in the elastin gene. In this article, the authors have discussed the etiology, morphology, clinical presentation and genetic basis of SVAS. Various surgical approaches, both conventional and recent, have been discussed and demonstrated with the aid of diagrams. Single-, two- and three-sinus methods have been presented, along with a comparative analysis of early results, associated procedures, late mortality and reoperation. In conclusion, the authors have described their institutional experience of more than 40 years in the surgical management of SVAS.

Partial aortic root remodeling in case of ascending aortic aneurysms

OBJECTIVE

In degenerative ascending aortic aneurysms (AAAs), the pathological process may extend into the aortic root, causing aortic regurgitation (AR). As often one or two sinuses are involved, ascending aorta replacement should be associated with selected sinus replacement.

METHODS

Thirty patients (21 men and 9 women; mean ± SD age, 70.0 ± 10.4) were operated on for ascending aorta and selected sinus replacement. All patients had degenerative AAA with sinotubular junction and partial root dilatation: one or two sinuses of Valsalva were involved. Mild to moderate-severe AR was present in all patients. The mean ± SD logistic EuroSCORE 1 was 15.4 ± 12.5. Twenty patients had ascending aorta replacement associated with noncoronary sinus replacement; 8 patients, associated with both right and noncoronary sinuses; 1 patient, associated with both left and noncoronary sinuses; and 1 patient, associated with left coronary sinus alone.

RESULTS

There were no hospital or late deaths. No thromboembolic event or bleeding complications were reported. Postoperative echocardiography did not show significant AR, and computed tomographic scanning revealed a normal positioning of the vascular graft in the ascending aorta.

CONCLUSIONS

Remodeling of the sinotubular junction with selected sinus replacement in degenerative AAA is a valuable approach for aortic root remodeling, leading to a significant reduction of AR when the aortic leaflets are normal.

The application of all-autologous three-sinus repair for supravalvular pulmonary stenosis

Various surgical techniques have been proposed for the repair of supravalvular pulmonary stenosis (SVPS) in pediatric populations. Whereas growth potential should be promised, excessive expansion under the presence of undiminished high pulmonary arterial pressure should be avoided. The authors applied all-autologous three-sinus repair, the so-called modified Brom or Myers technique, to SVPS and examined the midterm outcomes. Between March 2010 and March 2012, 15 patients (8 boys) with a median age of 12 months who had SVPS underwent all-autologous three-sinus repair. Of the 15 patients, 13 (87 %) had previously undergone pulmonary artery (PA) banding for treatment of high pulmonary vascular resistance. Two patients (13 %) had Noonan syndrome. A follow-up evaluation was completed for all the patients, and the median follow-up period was 13.5 months (range, 1 month to 2.4 years). No mortalities occurred. The diameter of the stenotic part at the main PA increased from 47.0 ± 14.1 % (range 29.1-70.0 %) of the normal PA diameter at the preoperative evaluation to 108.9 ± 25.7 % (range 58.9-148.1 %) at 6 months, and then to 104.7 ± 11.4 % (range 87.7-134.1 %) 1 year after the operation. The estimated mean pressure gradient across the main PA decreased from 76.2 ± 12.2 mmHg (range 57.8-108.2 mmHg) at the preoperative evaluation to 11.3 ± 12.0 mmHg (range 1.4-49.0 mmHg) at 6 months, and then to 6.4 ± 5.5 mmHg (range 2.0-19.4 mmHg) 1 year after the operation. No patients showed moderate or greater pulmonary insufficiency. The midterm outcomes after supravalvular pulmonary stenosis by all-autologous three-sinus repair were acceptable. Although a long-term follow-up evaluation is mandatory, application of this technique may provide a just enough growth of the reconstructed main pulmonary artery with symmetric pulmonary valve geometry.

The neoaortic root in children with transposition of the great arteries after an arterial switch operation

OBJECTIVES

Neoaortic root changes in children with transposition of the great arteries (TGA) are reportedly risk factors for the development of neoaortic regurgitation (NeoAR). The aims of this study were to assess the neoaortic root diameter and relative proportion in children with TGA after surgical correction and to identify possible correlations with the development of neoaortic insufficiency.

METHODS

Of the 611 children who had the arterial switch operation performed in the Cardiology Department of the Polish Mother's Memorial Hospital, 172 consecutive patients were qualified for this study. The inclusion criteria were: anatomical correction performed during the neonatal period, more than 10 years of postoperative observation and at least two full echocardiographic examinations.

RESULTS

NeoAR increased during postoperative follow-up and at the end of the observation period, 76% of the patients had NeoAR (27%-trace, 42%-mild, 7%-moderate and 0.6%-severe). Among the analysed risk factors for NeoAR development, the significant ones were arterial valve discrepancy (OR = 2.05; 95% CI: 1.04-4.02; P = 0.031) and the non-facing commissures (OR = 4.05; 95% CI: 1.34-11.9; P = 0.01). The neoaortic root diameter was not statistically significantly correlated with the presence of NeoAR or with the heart defects associated with transposition. The neoaortic root was initially, on average, 37% (z-score = 1.58) bigger than the aortic root in healthy children. This disproportion increased during the follow-up evaluations to 57% (z-score = 2.09).

CONCLUSIONS

The neoaortic root in children after the arterial switch procedure develops differently from that in healthy children, but this is not evidently related to NeoAR development or associated heart defects.

Optimal elastomeric scaffold leaflet shape for pulmonary heart valve leaflet replacement

Surgical replacement of the pulmonary valve (PV) is a common treatment option for congenital pulmonary valve defects. Engineered tissue approaches to develop novel PV replacements are intrinsically complex, and will require methodical approaches for their development. Single leaflet replacement utilizing an ovine model is an attractive approach in that candidate materials can be evaluated under valve level stresses in blood contact without the confounding effects of a particular valve design. In the present study an approach for optimal leaflet shape design based on finite element (FE) simulation of a mechanically anisotropic, elastomeric scaffold for PV replacement is presented. The scaffold was modeled as an orthotropic hyperelastic material using a generalized Fung-type constitutive model. The optimal shape of the fully loaded PV replacement leaflet was systematically determined by minimizing the difference between the deformed shape obtained from FE simulation and an ex-vivo microCT scan of a native ovine PV leaflet. Effects of material anisotropy, dimensional changes of PV root, and fiber orientation on the resulting leaflet deformation were investigated. In-situ validation demonstrated that the approach could guide the design of the leaflet shape for PV replacement surgery.

Aortic root conservative repair of acute type A aortic dissection involving the aortic root: fate of the aortic root and aortic valve function

OBJECTIVES

Despite many studies about aortic valve function and aortic root geometry after conservative aortic root repair of acute type A aortic dissection, the results are not always consistent or conclusive. This study aims to evaluate aortic root diameter and aortic valve function after surgery for acute type A aortic dissection involving the aortic root.

METHODS

A retrospective review was performed of 196 consecutive patients (age, 56.9 ± 11.4 years; 96 men) who underwent conservative aortic root repair including sinotubular junction resuspension for the management of acute type A aortic dissection involving the aortic root.

RESULTS

The 30-day mortality rate was 5.1% (n = 10). During a median follow-up period of 45.3 ± 36.4 months, there were 28 deaths and 11 cases of aortic reoperation (proximal reoperation in 1 and distal reoperation in 10). Of the 6-month survivors (n = 177, 90.3%), echocardiography and computed tomography were performed in the late period (>6 months) on 115 (65.0%) and 138 (78.0%), respectively. Significant aortic regurgitation (greater than grade 2+) or root dilatation (>45 mm) was observed in 5 and 19 patients, respectively. Freedom from aortic regurgitation (greater than grade 2+) or root dilatation (>45 mm) at 5 years was 84.6% ± 3.9%. On the Cox regression analysis, the maximal aortic root diameter at initial presentation was the only significant predictor of aortic regurgitation and aortic root dilatation (hazard ratio, 1.10; 95% confidence interval, 1.02-1.19; P = .014).

CONCLUSIONS

Conservative aortic root repair of acute type A aortic dissection demonstrates acceptable long-term clinical outcomes. However, more aggressive approaches should be considered for patients who have aortic root dilatation because of the risk of developing a root aneurysm after surgery.

Mid-term results after sinutubular junction remodelling with aortic cusp repair

OBJECTIVES

An ascending aortic aneurysm with aortic valve regurgitation (AR) may be treated by sinutubular junction remodelling (STJR) with aortic cusp repair if the root diameter is preserved. We analysed the outcome of STJR with cusp repair.

METHODS

Between 1995 and 2010, 1094 patients underwent valve-preserving surgery. Of these, 560 individuals with root replacement, 128 patients with acute aortic dissection and 262 patients with preoperative AR ≤ II were excluded. The remaining 144 patients (mean age 56.0 ± 17.0 years, 103 males) underwent STJR ± cusp repair for ascending aortic aneurysm and AR ≥ III. In all, sinus dimensions were preserved according to the following criteria: maximum diameter ≤42 mm in bicuspid aortic valve (BAV, n = 59) and unicuspid aortic valve (UAV, n = 27), and ≤45 mm in tricuspid aortic valves (TAV, n = 58). In BAV, right-left (n = 52) and right-non-coronary (n = 7) cusp fusions were seen. To evaluate the influence of valve morphology, patients were divided into two groups: TAV and non-TAV. The patients with non-TAV were younger (P < 0.01) and had less concomitant cardiac surgery (P < 0.01). The mean follow-up was 25.9 ± 22.0 months.

RESULTS

Early mortality was 2.1% (n = 3). The causes of death were cardiac (n = 1), respiratory (n = 1) and mesenteric ischaemia (n = 1). Higher age was the predictor of early mortality by multivariate analysis (P = 0.04, hazard ratio 13.2). Overall 5-year survival was 93.9 ± 2.9% (TAV, 82.8 ± 10.2%; non-TAV, 98.5 ± 1.5%; P = 0.02). Causes of late death were cardiac (n = 1), respiratory (n = 1) and carcinoma (n = 1). Freedom from recurrent AR ≥ III at 5 years was 80.1 ± 7.7% (TAV, 97.0 ± 3.0%; non-TAV, 73.4 ± 8.7%; P = 0.02). By multivariate analysis, only aortoventricular junction (AVJ) > 28 mm (P < 0.01, hazard ratio 9.7) was a predictor of recurrent AR. Freedom from reoperation at 5 years was 81.9 ± 7.8% (TAV, 97.0 ± 3.0%; non-TAV, 76.6 ± 8.8%; P < 0.05). The causes of reoperation (five re-aortic valve repairs and four valve replacements) were dehiscence of pericardial patch (n = 7) and recurrent cusp prolapse (n = 2). By multivariate analysis, only AVJ > 28 mm was a significant predictor for reoperation (P < 0.01, hazard ratio 11.6).

CONCLUSIONS

STJR with cusp repair is a useful technique in patients with an ascending aortic aneurysm and relevant AR. Although the dilated AVJ is a risk of recurrent AR and reoperation, concomitant cusp repair is associated with an acceptable mid-term outcome.

Aortic root aneurysm: principles of repair and long-term follow-up

OBJECTIVES

This study was undertaken to examine clinical and echocardiographic outcomes of aortic valve-sparing operations to treat aortic root aneurysms.

METHODS

From May 1988 to December 2007, a total of 228 patients underwent reimplantation of the aortic valve, and 61 underwent remodeling of the aortic root. Patients were followed up prospectively and had echocardiographic evaluation of valve function. Mean follow-up was 7.28 ± 4.33 years.

RESULTS

There were 5 operative and 26 late deaths. Survival at 12 years was 82.9 ± 3.7% and similar between types of operations. Age and aortic dissection were independent predictors of mortality. Seven patients have had reoperations on the aortic valve: 6 for aortic insufficiency and 1 for endocarditis. Five of these patients had undergone remodeling of the aortic root. Freedoms from reoperation at 12 years were 94.3% ± 2.6% among all patients, 90.4% ± 4.7% after remodeling, and 97.4% ± 2.2% after reimplantation (P = .09). Postoperatively, moderate aortic insufficiency developed in 14 patients (8 remodeling and 6 reimplantation) and severe aortic insufficiency in 5 (3 remodeling and 2 reimplantation). The remaining patients had mild, trace, or no aortic insufficiency. Freedoms from moderate or severe aortic insufficiency at 12 years were 86.8% ± 3.8% among all patients, 82.6% ± 6.2% after remodeling, and 91.0% ± 3.8% after reimplantation (P = .035). Only age-by 5-year increments-was an independent predictor of postoperative aortic insufficiency.

CONCLUSIONS

Aortic valve-sparing operations provide excellent patient survival and stable aortic valve function, particularly after reimplantation of the aortic valve.

Aortic valve pathophysiology during left ventricular assist device support

The increased applicability and excellent results with left ventricular assist devices (LVADs) have revolutionized the available treatment options for patients with advanced heart failure. Pre-existing valve abnormalities are common in this population, and subsequent development of valve abnormalities after LVAD placement is also often noted. Although native mitral and tricuspid valve disease is more common in heart failure patients before LVAD placement, aortic valves are much more likely to generate abnormal pathophysiology in the LVAD patient during as well as after LVAD placement. The aim of this comprehensive review is to review aortic valve function in LVAD patients and highlight the consideration of pre-existing valve disease on patient treatment at the time of LVAD implant. The basis for structural changes leading to valve pathophysiology during and after LVAD placement will be described, providing a basis for improved clinical understanding and new strategies to prevent these conditions.

[Pathobiology of idiopathic ascending aortic aneurysms]

BACKGROUND

The majority of ascending aortic aneurysms cannot be related to any specific etiology and should be qualified as idiopathic. The incidence of this disease is increasing in the population of the developed countries but its pathobiology is poorly understood.

AIM

This article is reviewing the publications concerning the pathobiology of idiopathic ascending aortic aneurysms.

SOURCES

A PubMed search on articles published in English or French, between January 1965 and December 2007, on key-words << aortic root >>, << ascending aorta >>, << aortic arch >>, << thoracic aorta >>, << aneurysm >>, << dilatation >> and << dissection >> was undertaken. Articles on aneurysms related to inflammatory and infectious diseases, congenital or genetic syndromes were excluded.

RESULTS

The presented data suggests that destructive remodeling of the aortic wall, inflammation and angiogenesis, biomechanical wall stress, and molecular genetics are relevant mechanisms of idiopathic ascending aortic aneurysm formation and progression.

LIMITS

Sparse data available from few direct studies offer limited knowledge on pathobiology of idiopathic ascending aortic aneurysms.

CONCLUSION

A more intimate knowledge of the triggers and perpetrating factors of this disease might offer new diagnostic and treatment options.

Postimplantation morphologic changes of glutaraldehyde-fixed porcine aortic roots and risk of aneurysm and rupture

OBJECTIVE

Rupture of glutaraldehyde-fixed porcine aortic roots has been reported, but the mechanism and incidence of this complication is unknown. This study evaluates the clinical outcomes and the risk of dilation and rupture of porcine aortic roots after implantation.

METHODS

Commercially available porcine aortic roots were used for aortic root replacement in 308 patients (Freestyle bioprosthesis [Medtronic, Minneapolis, Minn] in 251 patients and Toronto Root [St Jude Medical, St Paul, Minn] in 57 patients) whose mean age was 62 +/- 13 years. The main indication for aortic root replacement was dilation of the native aortic root. Clinical follow-up was complete at a mean of 5.3 +/- 2.5 years. Valve function and aortic root diameter were assessed by means of echocardiography.

RESULTS

There were 10 (3.2%) operative and 39 (12.6%) late deaths. At 8 years, patients' survival was 79.0% +/- 3.1%, freedom from reoperation was 95.3% +/- 1.7%, and freedom from severe aortic insufficiency was 93.8% +/- 2.7%. The diameter of the aortic sinuses increased from 31.9 +/- 4.3 to 34.1 +/- 4.8 mm (P < .0001), and it exceeded 40 mm in 10% of the patients. Linear regression analysis revealed that the duration of follow-up (P < .0001) and the size of the valve implanted (P < .0001) were associated with risk of sinus dilation. There was only 1 early rupture of the noncoronary aortic sinus and 2 late aneurysms that required repeat operations. Histologic examination of explanted aneurysmal porcine roots revealed marked changes in the xenograft arterial wall, with abundant mononuclear cells suggestive of immunologic reaction.

CONCLUSIONS

Mild dilation of porcine aortic roots after aortic root replacement is common, but aneurysm formation and rupture are rare during the first decade of follow-up. Annual surveillance with echocardiography is recommended.

Sinotubular Junction Size Affects Aortic Root Geometry and Aortic Valve Function in the Aortic Valve Reimplantation Procedure: An In Vitro Study Using the Valsalva Graft

BACKGROUND

Sinotubular junction (STJ) size in aortic valve reimplantation procedures is usually predetermined on the basis of experience or intraoperative mathematical calculations. Given the small coaptation reserve of aortic valve leaflets, small errors can produce an incompetent aortic valve. We tested in vitro the effect of geometrically changing the relationship between aortic annulus size and STJ size on aortic root geometry and aortic valve function.

METHODS

Twenty-five-millimeter diameter scalloped porcine aortic roots were reimplanted into 32-mm Valsalva grafts (Vascutek, Renfrewshire, Scotland), suspending commissures into the expandable region of the graft itself. Neoaortic roots were pressurized up to 100 mm Hg. Sinotubular junction size was then changed by wrapping the neocommissural ridge with Dacron rings of decreasing size. Geometry of the aortic root, anatomy of aortic valve leaflets, and extent of their coaptation were analyzed by direct endoscopic view and by ultrasound imaging techniques.

RESULTS

Pressurizing unwrapped aortic root resulted in centrifugal displacement of commissures, aortic leaflets tethering and bending, and central aortic regurgitation. By reducing STJ size, coaptation height of aortic valve leaflets first increased to reach a maximum for an STJ size corresponding to 30 mm, and then decreased for further reduction of STJ size. Excess reduction of STJ size also resulted in prolapsed aortic leaflets and eccentric aortic regurgitation.

CONCLUSIONS

In the reimplantation procedure performed with a Valsalva graft, aortic valve function and leaflet coaptation can be optimized by optimizing STJ size.

Heart valve macro- and microstructure

Each heart valve is composed of different structures of which each one has its own histological profile. Although the aortic and the pulmonary valves as well as the mitral and the tricuspid valves show similarities in their architecture, they are individually designed to ensure optimal function with regard to their role in the cardiac cycle. In this article, we systematically describe the structural elements of the four heart valves by different anatomical, light- and electron-microscopic techniques that have been presented. Without the demand of completeness, we describe main structural features that are in our opinion of importance in understanding heart valve performance. These features will also have important implications in the treatment of heart valve disease. They will increase the knowledge in the design of valve substitutes or partial substitutes and may participate to improve reconstructive techniques. In addition, understanding heart valve macro- and microstructure may also be of benefit in heart valve engineering techniques.

Adjustable Sinotubular Junction for Aortic Valve Reimplantation Procedures

Sinotubular junction size in aortic valve reimplantation procedures is usually predetermined on the basis of mathematical calculations and intraoperative measurements. We propose a new method for aortic valve reimplantation by which intraoperative measurements can be eliminated and sinotubular junction size adjusted after cross clamp removal to fit the patient's need. Aortic valve commissures are reimplanted in the expandable skirt of a Valsalva (Vascutek, Renfrewshire, Scotland) graft to realize an oversized sinotubular junction that is subsequently reduced to the proper size by wrapping, with Dacron rings of decreasing size, the neo-sinotubular ridge under transesophageal echocardiographic guidance.

Geometric modeling of functional trileaflet aortic valves: Development and clinical applications

The dimensions of the aortic valve components condition its ability to prevent blood from flowing back into the heart. While the theoretical parameters for best trileaflet valve performance have already been established, an effective approach to describe other less optimal, but functional models has been lacking. Our goal was to establish a method to determine by how much the dimensions of the aortic valve components can vary while still maintaining proper function. Measurements were made on silicone rubber casts of human aortic valves to document the range of dimensional variability encountered in normal adult valves. Analytical equations were written to describe a fully three-dimensional geometric model of a trileaflet valve in both the open and closed positions. A complete set of analytical, numerical and graphical tools was developed to explore a range of component dimensions within functional aortic valves. A list of geometric guidelines was established to ensure safe operation of the valve during the cardiac cycle, with practical safety margins. The geometry-based model presented here allows determining quickly if a certain set of valve component dimensions results in a functional valve. This is of great interest to designers of new prosthetic heart valve models, as well as to surgeons involved in valve-sparing surgery.

Evaluation of native valve-sparing aortic root reconstruction with direct imaging--reimplantation or remodeling?

BACKGROUND

Aortic root reimplantation and remodeling have been used to preserve the native aortic valve. However, direct observation of valve motions with these techniques has not been performed.

METHODS

Mongrel dogs were studied. The beating heart model was created using modified Tyrode's solution. Normal aortic valves and aortic valves preserved with the remodeling or reimplantation procedure were observed with an endoscope, and behavior was recorded on a high-speed video (200 frames/s). The aortic valve orifice area was measured at 11 data points per beat. A predictable maximum valve orifice area was defined as an area encircled by the three commissures. A ratio of each aortic valve orifice area to the predictable maximum valve orifice area was calculated. The control group, the reimplantation group, and the remodeling group were compared.

RESULTS

The preserved aortic valve with reimplantation showed bending and asymmetric motion. The ratio of aortic valve orifice area and predictable maximum valve orifice area in the reimplantation group was significantly smaller compared with the control and remodeling groups.

CONCLUSIONS

The opening and closing behavior of the aortic valve preserved with the reimplantation procedure was impaired. It was speculated that the remodeling procedure may preserve more physiologic root function compared with the reimplantation procedure.

Prevalence and predictors of neoaortic regurgitation after arterial switch operation for transposition of the great arteries

BACKGROUND

The fate of the native pulmonary valve after arterial switch operation is still unknown and may become a cause for a secondary aortic valve operation during adult life. We evaluated the prevalence and predictive factors associated with neoaortic valvular regurgitation by a retrospective study of children who underwent arterial switch operation for transposition of the great arteries.

METHODS

The onset of neoaortic valvular regurgitation was correlated with demographic data, cardiac anatomy, surgical technique, and postoperative ventricular function. The size of the neoaortic root and ascending aorta was measured in a selected subset of patients.

RESULTS

Among 253 survivors, 173 were eligible for the study. After a median follow-up time of 8.2 years, 61 patients showed echocardiographic or angiographic evidence of valvular incompetence, which was progressive in 14 cases; this led to surgical intervention in 2 patients, and there was 1 operative death. At multivariate analysis, the onset of valvular regurgitation was correlated with the trap-door technique for coronary reimplantation (P <.01). A smooth transition from the aortic sinus to the ascending aorta, with loss of the normal sinotubular junction geometry, may be associated with valvular incompetence.

CONCLUSIONS

After arterial switch operation, there is an increasing frequency of neoaortic regurgitation, which may lead to significant valvular dysfunction later in life. The trap-door type of coronary reimplantation is associated with an increased risk for valvular dysfunction, possibly because of a distortion of the sinotubular junction geometry. For this reason, we recommend the punch technique for repair in all but the most complicated coronary pattern.

Impact of preoperative aortic root diameter on long-term aortic valve function after valve sparing aortic root reimplantation

BACKGROUND

Valve sparing aortic root reimplantation technique in patients with aortic root aneurysm have shown excellent mid-term results. In conjunction with the diameter of the aortic root the mechanical leaflet stress increase, which might have an impact on long-term aortic valve function after valve sparing aortic root reimplantation.

METHODS AND RESULTS

From July 1993 to October 2001, 168 patients with aortic root aneurysm underwent valve sparing aortic root reimplantation. Patients with type A aortic dissection were excluded. Thus, 123 patients were analyzed. We identified 47 patients with an preoperative aortic root diameter exceeding 60 mm (group A), 58 patients with an diameter between 50 and 60 mm (group B), and 18 patients with a diameter less than 50 mm (group C). The groups were compared regarding mortality, long-term survival, freedom from reoperation, freedom from severe and moderate aortic valve insufficiency (AI), and postoperative morbidity. Mean follow-up (group A 43+/-26 months, group B 40+/-25 months, group C 23+/-19 months; group C versus group A, P=0.005; group C versus group B, P=0.011) was shorter in group C. Perioperative mortality (group A 2.2%, group B 1.9%, group C 5.2%; P=ns) was comparable between the groups with each one patient. The 3-year survival for group A was 98+/-2%, for group B 96+/-3%, and for group C 100+/-0% (P=ns). Freedom from reoperation for group A was 98+/-2%, for group B 96+/-3%, and for group C 88+/-8% (P=ns). Four patients developed severe or moderate AI, thus freedom from severe and moderate AI for group A was 100+/-0%, for group B 88+/-8%, and for group C 94+/-5% (P=ns). During follow-up no thromboembolic or bleeding events were noticed.

CONCLUSIONS

Our data show that the preoperative diameter of the aortic root has no impact on the longevity of the repair. Thus, the reimplantation technique can be recommended for all patients presenting with an aortic root aneurysm and normal leaflets regardless of the aortic root diameter.

The Ross procedure in adults: intermediate-term results

BACKGROUND

The durability of the Ross procedure may be optimized by appropriate geometric matching of the aortic and pulmonary artery roots. We employed a surgical strategy to standardize the operation in order to avoid more readily a geometric mismatch.

METHODS

The Ross procedure was performed as a root replacement. Without regard for patient body surface area, the aortic annulus was plicated to 23 mm and externally buttressed with felt. Geometric mismatch of the distal autograft anastomosis was avoided by liberal use of a synthetic interposition graft, and the anastomosis was also externally buttressed with felt. An over-sized pulmonary homograft (27 to 28 mm) was routinely used to reconstruct the right ventricular outflow tract.

RESULTS

Forty-four consecutive patients (27 men and 17 women; mean age, 49 +/- 9 years) were operated on between January 1997 and March 2002. Mean follow-up was 38 +/- 5 months. Twenty-nine patients had aortic stenosis and 15 had aortic regurgitation. Aortic annular plication was done in 41 (93%) and an aortic interposition was used in 14 (32%). There were three hospital deaths, with no subsequent deaths. Only 1 patient required reoperation 2.5 years postoperatively from recurrent endocarditis. No patient has more that "trivial" autograft insufficiency, and the mean autograft gradient was 7 +/- 3 mm Hg. No patient has significant pulmonary homograft stenosis.

CONCLUSIONS

Geometric matching of the aortic and pulmonary roots may be readily accomplished using a standardized approach to the Ross procedure. In turn, this may optimize the durability of the operation.

Aortic root endoscopy in pediatric cardiac operations for aortic valvuloplasty

We use aortic root endoscopy for assessment of the aortic valve in pediatric patients. A flexible fiberscope inserted through the ascending aorta provides clear and precise visualization of the aortic valve. This technique of endoscopic assessment will help to judge the cusp prolapse and malcoaptation of the aortic valve in pediatric aortic surgery.

Geometrical difference between an ascending aneurysm and a root aneurysm in valve-sparing operations

OBJECTIVE

The aortic root geometry of the leaflet size and coaptation in an ascending aortic aneurysm, and in a root aneurysm, may predict the early and late outcomes from valve-sparing surgery.

METHODS

The aortic root was investigated using intraoperative endoscopy before and after valve-sparing root reconstruction. The definition of 'root aneurysm' was marked sinus dilatation proximal to the sinotubular junction. 'Ascending aneurysm' was defined as dominant dilatation distal from the sinotubular junction. Fifteen cases were examined and classified into two groups; Group A with an ascending aneurysm (four patients), and Group R with a root aneurysm (eleven patients).

RESULTS

Cusp prolapse was seen in 10 (90.9%) patients of Group R, and in only one (25%) patient of Group A. The length of the free margin of all cusps in Group R was significantly longer than those in Group A. In Group R, the lengths of the free margin of an individual cusp were significantly different, indicating asymmetric cusps. In Group A, the length of the free margin were similar, indicating symmetric cusps. There was no significant difference in the degree of immediate postoperative aortic insufficiency, between the two groups. At the most recent follow-up, progressive aortic insufficiency was present in two patients of Group R.

CONCLUSIONS

A root aneurysm had asymmetric, elongated and prolapsed aortic cusps, while an ascending aneurysm had symmetric cusps without prolapse. The mechanism of aortic insufficiency in a root aneurysm was more complex, suggesting a difficulty in achieving long-term valve competence. Such geometrical difference should be considered in the indication for the surgical technique of valve-sparing operations.