Hemodynamics and wall shear metrics in a pulmonary autograft: Comparing a fluid-structure interaction and computational fluid dynamics approach

OBJECTIVE

In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation.

METHODS

The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps.

RESULTS

Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p < 0.01) for TAWSS and (r > 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI.

CONCLUSION

FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA.

Ross procedure: valve function, clinical outcomes and predictors after 25 years' follow-up

OBJECTIVE

To describe long-term outcomes of the Ross procedure in a single center and retrospective series after 25 years follow-up.

METHODS

From 1997-2019 we included all consecutive patients who underwent Ross procedure at our center. Clinical and echocardiographic evaluations were performed at least yearly. Echocardiographic valvular impairment was defined as at least moderate autograft or homograft dysfunction. Reintervention outcomes included surgical and percutaneous approach.

RESULTS

151 Ross procedures were performed (mean age 28±12years, 21 %<16years, 70 %male). After 25 years follow-up (median 18 years, interquartile range 9-21, only 3 patients lost) 12 patients died (8 %); Autograft, homograft or any valve dysfunction were present in 38(26 %), 48(32 %) and 75(51 %), respectively; and reintervention in 22(15%), 17(11%) and 38(26 %) respectively. At 20 years of follow-up, probabilities of survival free from autograft, homograft or any valve dysfunction were 63 %, 60 % and 35 %; and from reintervention, 80 %, 85 % and 67 %, respectively. The learning curve period (first 12 cases) was independently associated to autograft dysfunction (HR 2.78, 95 %CI:1.18-6.53, p = 0.02) and reintervention (HR 3.76, 95 %CI: 1.46-9.70, p = 0.006). Larger native pulmonary diameter was also an independent predictor of autograft reintervention (HR 1.22, 95 %CI:1.03-1.45, p = 0.03). Homograft dysfunction was associated with younger age (HR 5.35, 95 %CI: 2.13-13.47, p<0.001) and homograft reintervention, with higher left ventricle ejection fraction (HR 1,10, 95 %CI:1.02-1.19, p<0.02).

CONCLUSIONS

In this 25 years' experience after the Ross procedure, global survival was high, although autograft and homograft dysfunction and reintervention rates were not negligible. Clinical and echocardiographic variables can identify patients with higher risk of events in follow up.

Ross procedure with personalized external aortic root support

The Ross-Personalized External Aortic Root Support procedure is a surgical aortic valve replacement technique in which the autologous pulmonary valve is transposed in the aortic position to replace the malfunctioning aortic valve and a homograft is implanted in the pulmonary position. To prevent autograft dilatation, a Personalized External Aortic Root Support prosthesis is included in the proximal autograft anastomosis and wrapped around the ascending aorta. The aorta is transected transversely, the aortic valve is resected, and the coronary arteries are mobilized and cut out of the sinuses, leaving a rim. The pulmonary autograft is harvested by transecting the pulmonary artery and part of the right ventricular outflow tract. The autograft is approximated to the aortic root and inverted inside the ventricle. The proximal anastomosis is performed including the prosthesis between the aortic root and the autograft. The coronary buttons are threaded through appropriately positioned and sized holes in the prosthesis and reimplanted into the autograft. The ascending aorta is appropriately adapted and anastomosed with the distal autograft. When the patient is off cardiopulmonary bypass, the prosthesis can be closed longitudinally and is anchored to the distal aortic adventitia.

Structural dysregulation of the pulmonary autograft was associated with a greater density of p16INK4A-vascular smooth muscle cells

The present study tested the hypothesis that a senescent phenotype of vascular smooth muscle cells (VSMCs) may represent the seminal event linked to maladaptive pulmonary autograft remodeling of a small number of patients that underwent the Ross procedure. The diameter of the pulmonary autograft (47±4 mm) of three male patients was significantly greater compared to the pulmonary artery (26±1 mm) excised from bicuspid aortic valve (BAV) patients. The pulmonary autograft was associated with a neointimal region and the adjacent medial region was significantly thinner compared to the pulmonary artery of BAV patients. Structural dysregulation was evident as elastin content of the medial region was significantly reduced in the pulmonary autograft compared to the pulmonary artery of BAV patients. By contrast, collagen content of the medial region of the pulmonary autograft and the pulmonary artery of BAV patients was not significantly different. Reduced medial elastin content of the pulmonary autograft was associated with increased protein levels of matrix metalloproteinase-9. The latter phenotype was not attributed to a robust inflammatory response as the percentage of Mac-2⁽⁺⁾-infiltrating monocytes/macrophages was similar between groups. A senescent phenotype was identified as protein levels of the cell cycle inhibitor p27^kip1 were upregulated and the density of p16^INK4A/non-muscle myosin IIB⁽⁺⁾-VSMCs was significantly greater in the pulmonary autograft compared to the pulmonary artery of BAV patients. Thus, senescent VSMCs may represent the predominant cellular source of increased matrix metalloproteinase-9 protein expression translating to maladaptive pulmonary autograft remodeling characterized by elastin degradation, medial thinning and neointimal formation.

Pregnancy outcomes in women following the Ross procedure

INTRODUCTION

The Ross procedure, where a pulmonary autograft (neoaorta) replaces the aortic valve, has excellent long-term outcomes in patients with congenital aortic valve disease. However, there are reports of neoaortic dilatation and dissection. An increasing number of women are wishing to become pregnant following the Ross procedure, but little is known about the occurrence and risks of neoaortic dilatation and complications in pregnancy. We investigated neoaorta function and outcomes in pregnancy following the Ross procedure.

METHODS

This retrospective study investigated women post-Ross procedure at a tertiary ACHD unit between 1997 and 2021. Imaging evaluated neoaortic root dimensions and regurgitation pre-, and post- pregnancy, compared with matched non-pregnant controls. Primary endpoints were change in neoaortic dimensions, degree of regurgitation and adverse maternal outcomes.

RESULTS

Nineteen pregnancies in 12 women were included. The mean change in neoaortic root diameter post-pregnancy was 1.8 mm (SD 3.4) (p = 0.017). There was no significant change in neoaortic dimensions in matched controls during follow-up. There were no cases of dissection, arrhythmia, acute coronary syndrome, or maternal mortality. Three deliveries were pre-term, including one emergency Caesarean section due to maternal cardiac decompensation, requiring aortic root replacement post-partum but there were no neonatal deaths.

CONCLUSIONS

Pregnancy following the Ross procedure is associated with neoaortic dilatation, and pregnancy is generally well tolerated. Although adverse maternal outcomes are uncommon, there are still rare cases of cardiac complications in and around the time of pregnancy. These findings emphasise the need for accessible pre-pregnancy counselling, risk stratification and careful surveillance through pregnancy by specialist cardio-obstetric multi-disciplinary teams.

Long-term Outcomes of the Ross Procedure for Young Patients with Aortic Valve Disease

To define current role of the Ross operation in young patients, the outcome in those followed longer than 20 years were assessed. Between 1994 and 2020, 81 consecutive patients, 70 of 11 male and/or female, mean age 27 years underwent Ross procedure, accruing 20 years of follow-up or longer. Sixty-four had bicuspid valve (79%) and 54 (67%) aortic insufficiency, while 15 (19%) had undergone prior operations. Surgery consisted in root replacement in 53 patients, cylinder inclusion in 20 and sub-coronary graft in 8. There were 7 late deaths in 80 hospital survivors (median follow-up 21 years, IQR 20-23), with 88% ± 5% survival at 25 years. Thirty-four patients required left, 6 left and/or right and 1 right heart valve reoperation, on average 13 years after Ross procedure. Reoperation was valve-sparing in 18 (45%) patients and valve and/or root replacement in 22. Ten (24%) reoperated patients required a second reoperation 18 years after Ross procedure. Freedom from autograft reoperation was 46% ± 6%, while from autograft valve replacement was 60% ± 7%, thanks to autograft valve-sparing. Freedom from isolated right valve reoperation was 98% ± 4%. No mortality was associated with any of the 51 reoperations. Root technique was associated with reoperation (P = 0.024). Age at follow-up was 50 years (IQR 36-60), with 70 (96%) patients in NYHA class I and 6 (55%) women carrying out pregnancies. Young patients undergoing the Ross procedure enjoy unprecedented survival well into the third decade of follow-up, even when faced with reoperation. At 25 years risk of autograft reoperation is consistent, while negligible for homograft. Technical improvements at operation and valve-sparing at reoperation may prolong autograft valve durability.

Outcomes of the Ross procedure in young adults with previous aortic valve interventions

OBJECTIVES

Contemporarily modified Ross procedure continues to deliver excellent outcomes and remains part of the treatment strategy for aortic valve disease in the young adult population. The aim of this study was to assess whether Ross procedure carried out as a second or subsequent intervention for aortic valve disease carries similar risk and long-term benefit, when compared to Ross procedure for the first-time aortic valve replacement.

METHODS

A total of 158 patients aged 16-60 years from a single congenital cardiac centre between 1997 and 2020 were included. The sample was split into 2 subgroups, based on the history of previous aortic valve interventions prior to the Ross procedure. Primary outcomes were defined as survival and pulmonary autograft failure. Coarsened exact matching was used to balance for covariates.

RESULTS

A total of 103 patients underwent primary Ross and 55 underwent secondary Ross with a mean follow-up of 7.8 years. Twenty-two patients underwent 28 reoperations during follow-up. Forty-nine well-matched pairs were obtained through matching. Freedom from pulmonary autograft failure at 10 years was 84.5% in the primary group vs 100% in the secondary group (P = 0.021). Five- and ten-year survival were identical, 97.5% in the primary group vs 95.6% in the secondary group (P = 0.53). Male sex and era were found to be predictors of neoaortic root dilatation.

CONCLUSIONS

The lower incidence of graft failure seen in secondary Ross could justify a stepwise approach to aortic valve intervention. Ross procedure delivers excellent outcomes in the adult population with no difference in survival for primary or secondary Ross.

Long-term Results of the Ross Operation in Rheumatic Valve Disease

AIMS

To evaluate the impact of rheumatic heart disease on the long-term outcomes of the Ross Operation when compared to patients with bicuspid aortic valves.

METHODS AND RESULTS

We analyzed patients with rheumatic disease and bicuspid aortic valves who underwent a Ross Operation between 1995 and 2020. The primary outcomes were late survival and reoperations on the pulmonary autograft and the right ventricular allograft. We also performed a propensity score analysis to adjust for differences in baseline characteristics. The cumulative incidence of the events in the matched cohorts was compared using the Fine-Gray model.There were 147 patients with rheumatic disease and 314 with bicuspid valves. In the unmatched population, patients with rheumatic disease were younger, more symptomatic, had worse left ventricular function and were more likely to present a preoperative diagnosis of aortic insufficiency. Propensity matching resulted in 86 pairs with similar baseline characteristics. Compared with those with bicuspid valves, rheumatic patients had similar 20-years survival both in the unmatched (RHD = 67.8% vs BAV = 79.7%, p = 0.27) and matched cohorts (RHD = 72.5% vs BAV = 82.9%, p = 0.46). Cumulative incidence of reoperations on the pulmonary autograft after 20 years was also comparable between them in the unmatched (RHD 13.4% vs BAV 14.4%, p = 0.67) and matched patients (RHD 11.6% vs BAV p 21.1%, p = 0.47). Pulmonary autograft dysfunction due to rheumatic involvement was detected in only three occasions. Cumulative incidence of reoperations on the right sided allograft was higher in the unmatched cohort (RHD = 5.5% vs BAV = 16.7%, p = 0.035), but became non-significant after propensity score matching (RHD = 9.9% vs BAV = 32.3%, p = 0.051). The cumulative incidence of all Ross-related reoperations was similar in both groups.

CONCLUSIONS

Among patients undergoing Ross Operation, patients with rheumatic heart disease had similar long-term survival and rates of reoperations, when compared to patients with bicuspid aortic valves.

The Ross procedure in adult patients: a single-Centre analysis of long-term results up to 28 years

OBJECTIVES

This study aimed to provide an in-depth insight into our single-centre experience with the Ross procedure.

METHODS

All adults who underwent the Ross procedure between 1991 and 2014 were included. Based on the total number of Ross procedures performed by each surgeon at our centre during this 24-year period, surgeon volume was classified as low (<25 procedures), intermediate (25-44 procedures), and high (≥45 procedures). Survival, complications and reinterventions were evaluated. A single cardiologist assessed the pulmonary autograft's function and the neoaortic root diameter by echocardiography.

RESULTS

The outcomes of 224 patients [176 men, 48 women; mean age 37.2 (standard deviation 10.0) years] were analysed. Patients operated on by a low-volume surgeon had 7.22 times higher odds (P < 0.001) for a serious adverse event during the intraoperative or early postoperative course than patients operated on by a high-volume surgeon. Early mortality was 1.8%. Overall survival was 87.3% at 20 years. Compared with the demographically matched general population, the patients' survival was significantly lower (P = 0.002). The cumulative incidence of autograft and right ventricular outflow tract conduit reintervention was 21.5% and 5.9% at 20 years, respectively. Patients with preoperative aortic regurgitation had 6.25 times the subdistribution hazard of autograft reintervention (Bonferroni-adjusted P = 0.042) and a higher neoaortic root z-score [1.37 (standard deviation 2.04) versus 0.17 (standard deviation 1.81), P = 0.004] than patients with aortic stenosis. In patients with preoperative aortic regurgitation, autograft wrapping (remnant aortic wall and/or Vicryl® mesh) was associated with a 74% reduction in the subdistribution hazard of autograft reintervention (Bonferroni-adjusted P = 0.002) and with a reduced incidence of neoaortic root dilatation (P = 0.037).

CONCLUSIONS

The Ross procedure performed by a specialized surgeon provides very satisfying long-term results. The higher risk of autograft reintervention in preoperative aortic regurgitation may be counteracted by supporting the autograft.

The effectiveness and safety of pulmonary autograft as living tissue in Ross procedure: a systematic review

BACKGROUND

Reports on effectiveness and safety after the implant of pulmonary autograft (PA) living tissue in Ross procedure, to treat both congenital and acquired disease of the aortic valve and left ventricular outflow tract (LVOT), show variable durability results. We undertake a quantitative systematic review of evidence on outcome after the Ross procedure with the aim to improve insight into outcome and potential determinants.

METHODS

A systematic search of reports published from October 1979 to January 2021 was conducted (PubMed, Ovid Medline, Ovid Embase and Cochrane library) reporting outcomes after the Ross procedure in patients with diseased aortic valve with or without LVOT. Inclusion criteria were observational studies reporting on mortality and/or morbidity after autograft aortic valve or root replacement, completeness of follow-up >90%, and study size n≥30. Forty articles meeting the inclusion criteria were allocated to two categories: pediatric patient series and young adult patient series. Results were tabulated for a clearer presentation.

RESULTS

A total of 342 studies were evaluated of which forty studies were included in the final analysis as per the eligibility criteria. A total of 8,468 patients were included (7,796 in pediatric cohort and young adult series and 672 in pediatric series). Late mortality rates were remarkably low alongside similar age-matched mortality with the general population in young adults. There were differences in implantation techniques as regard the variability in stress and the somatic growth that recorded conflicting outcomes regarding the miniroot vs the subcoronary approach.

DISCUSSION

The adaptability of lung autograft to allow for both stress variability and somatic growth make it an ideal conduit for Ross's operation. The use of the miniroot technique over subcoronary implantation for better adaptability to withstand varying degrees of stress is perhaps more applicable to different patient subgroups.

Contemporary Ross procedure outcomes: medium- to long-term results in 214 patients

OBJECTIVE

Our goal was to present 2 decades of our experience with the Ross procedure and its sequential modifications, adopted since 2010, to improve the reoperation rate.

METHODS

We performed a single-centre, retrospective review of database information and medical notes about the implantation technique: the freestanding root. We compared era 1 (1997-2009) and era 2 (2010-2019).

RESULTS

Between 1997 and 2019, a total of 214 Ross procedures were performed (71% men, median age 24 years) [interquartile range (IQR) 15-38]. Of these, 87% had various forms of congenital-dysplastic aortic valves. The median cross-clamping and bypass times were 173 (IQR 148-202) and 202 (IQR 182-244) min. The median postoperative stay was 6 days (2-77). Thirty-day mortality was 0.5%. The median follow-up time was 8.2 years (IQR 3.9-13.2). Survival at 10 and 20 years was 97% and 95%; freedom from greater than moderate aortic regurgitation or aortic valve intervention was 91% and 80%; and 93% of the patients were in New York Heart Association functional class I. Twenty (21%) patients operated on during era 1 and 6 (9%) during era 2 underwent autograft reoperations. The median follow-up time was 14.3 (IQR 11.5-17.4) and 4.8 (IQR 2.5-7) years. Freedom from autograft reoperation was 87% and 69% at 10 and 20 years, with no significant difference between eras. Freedom from homograft reoperation was 96% and 76% at 10 and 20 years. The presence of aortic regurgitation, infective endocarditis and era 1 were predictors of autograft reoperation. Male gender and era 1 were predictors of neoaortic root dilatation.

CONCLUSIONS

The contemporary modified Ross procedure continues to deliver excellent results and should remain part of the strategy to treat children and young adults requiring aortic valve replacement.

Lights and Shadows on the Ross Procedure: Biological Solutions for Biological Problems

The Ross procedure represents a valid option for aortic valve replacement in young adults and was repeatedly shown to restore survival to that of the age- and sex-matched general population. However, its major drawback relies in the risk of pulmonary autograft (PA) dilation, negative histological remodeling and need for reoperation. Several techniques and materials to reinforce the PA have been proposed. They mainly include Dacron, personalized external aortic root support with a polyethylene terephthalate mesh system, autologous aortic tissue and bioresorbable materials. Synthetic materials, despite widely used in cardiac surgery, have significant biocompatibility issues with the PA and their interaction with this living structure translates into negative remodeling phenomena and disadvantageous biomechanical behaviors. Conversely, biomaterials with tailored degradable profiles might be able to reinforce while integrating with the PA and enhance its remodeling capabilities. The recent advancement in this field are here discussed.

Mitral valve replacement with a pulmonary autograft: long-term follow-up in an infant

A 7-month-old boy with a complete atrioventricular septal defect presented with severe left atrioventricular valve regurgitation 4 months after complete repair. As the valve was unsuitable for the repair and the annulus was too small to accommodate a mechanical prosthesis, the modified mitral Ross operation was performed. The long-term outcome was uneventful for 12 years. The mitral Ross procedure is an old-described technique in which classically the pulmonary autograft is encased in a prosthetic conduit preventing any growth potential. On the contrary, the modified technique used in this case shows that the long-term function can be obtained. This procedure may be a valuable option when mitral valve replacement is necessary in infants.

Mitral Valve Replacement with a Pulmonary Autograft in an Infant

A 76-day-old infant weighing 3.4 kg was referred for surgical intervention for severe mitral valve stenoinsufficiency caused by leaflet fibrosis and calcification. He had experienced a cerebral infarction in the left middle cerebral artery territory, which was deemed attributable to an embolism of a calcified particle from the dysmorphic mitral valve. Because mitral valve replacement using a prosthetic valve was not feasible in this small baby, mitral valve replacement with a pulmonary autograft was performed. After a brief period of extracorporeal membrane oxygenation (ECMO) support, he was weaned from ECMO and was discharged home without further cardiovascular complications.

Mid-term Outcome of 100 Consecutive Ross Procedures: Excellent Survival, But Yet to Be a Cure

The Ross procedure offers excellent short-term outcome but the long-term durability is under debate. Reinterventions and follow-up of 100 consecutive patients undergoing Ross Procedure at our centre (1993-2011) were analysed. Follow-up was available for 96 patients (97%) with a median duration of 5.3 (0.1-17.1) years. Median age of the patient cohort was 15.2 (0.04-58.4) years with 76 males. 93% had underlying congenital aortic stenosis. Root replacement technique was applied in all. The most common valved conduits used for reconstruction of the right ventricular outflow tract were homografts (66 patients) and bovine jugular vein (Contegra^R) graft (31 patients). Additional procedures included Ross-Konno procedure (14%), resection of subaortic stenosis/myectomy (11%) and reduction plasty of the ascending aorta (25%). One patient died within the first 30 days (1%). Late deaths occurred in 4 patients (4%) 0.5-4.5 years postoperatively: causes included pulmonary hypertension due to endocardial fibroelastosis (2), subarachnoid haemorrhage (1) and sudden cardiac death (1). Five-year survival was 93.6 (95% CI 88.1-99.1)%. Moderate or severe aortic (autograft) regurgitation needing reoperation occurred in 8 patients with a 5-year freedom from autograft reoperation of 98.5 (95.6-100)%. Five-year freedom from reintervention (surgery or catheter based) on the right ventricular outflow tract conduit was 91.5 (85.5-96.5)%. Univariate predictors of this reinterventions were smaller graft size (p = 0.03) and use of a Contegra^R graft (p = 0.04). Ross procedure can be performed with low mortality and good survival in the long term. Most of the reinterventions are related to the neo-right ventricular outflow tract and may be partly attributed to the lack of growth. While the Ross Procedure remains an invaluable option for aortic valve disease in children, new solutions for the neo-pulmonary valve as well as for the less often occurring problems on the autograft are needed.

20 years experience with the Ross operation in middle-aged patients: the autologous principle is still alive

Objectives

Review our long-term results with the Ross operation in middle-aged patients.

Methods

Between 1995 and 2016, 129 consecutive patients (106 males); mean age (47.2 ± 5.2 years) underwent a Ross operation. Right ventricular outflow tract (RVOT) reconstruction was performed with cryopreserved (n = 45) or decellularized allografts (n = 84). Mean follow-up was 8.4 ± 5.3 years (0.1 20.5 years). We analyzed early and late mortality, as well as valve related events and the need for reoperations.

Results

Early mortality was 1.6% and late survival was 87.6% at 16 years. There were 4 reoperations on the pulmonary autograft (96% freedom at 16 years) and 2 on the pulmonary allografts (99% freedom at 16 years). The 16-year freedom from more than mild aortic insufficiency (AI) and a late root diameter >45 mm was 64% and 71%, respectively. Patients with the preoperative diagnosis of AI are at greater risk for these complications. Among the allografts, decellularized allografts showed superior freedom from structural valve dysfunction.

Conclusions

The Ross operation in this cohort was associated with long-term survival similar to the general population and low incidence of reoperations. Patients with the preoperative diagnosis of AI are at increased risk for late autograft insufficiency and root dilatation. Decellularized allografts presented the best results for reconstruction of the RVOT. These results support the conclusion that the Ross operation has an important role in the treatment of middle-aged patients with aortic valve disease, especially those with pure aortic stenosis.

Stress-shielding, growth and remodeling of pulmonary artery reinforced with copolymer scaffold and transposed into aortic position

Ross operation, i.e., the use of autologous pulmonary artery to replace diseased aortic valve, has been recently at the center of a vivid debate regarding its unjust underuse in the surgical practice. Keystone of the procedure regards the use of an autologous biologically available graft which would preserve the anticoagulative and tissue homeostatic functions normally exerted by the native leaflets and would harmoniously integrate in the vascular system, allowing for progressive somatic growth of aortic structures. With this respect, recently, some of the authors have successfully pioneered a large animal model of transposition of pulmonary artery in systemic pressure load in order to reproduce the clinical scenario in which this procedure might be applied and allow for the development and testing of different devices or techniques to improve the pulmonary autograft (PA) performance, by testing a bioresorbable mesh for PA reinforcement. In the present work, to support and supplement the in vivo animal experimentation, a mathematical model is developed in order to simulate the biomechanical changes in pulmonary artery subjected to systemic pressure load and reinforced with a combination of resorbable and auxetic synthetic materials. The positive biological effects on vessel wall remodeling, the regional somatic growth phenomena and prevention of dilatative degeneration have been analyzed. The theoretical outcomes show that a virtuous biomechanical cooperation between biological and synthetic materials takes place, stress-shielding guiding the physiological arterialization of vessel walls, consequently determining the overall success of the autograft system.

A multicentre evaluation of the autograft procedure for young patients undergoing aortic valve replacement: update on the German Ross Registry†

OBJECTIVES

Conventional aortic valve replacement (AVR) in young, active patients represents a suboptimal solution in terms of long-term survival, durability and quality of life. The aim of the present work is to present an update on the multicentre experience with the pulmonary autograft procedure in young, adult patients.

METHODS

Between 1990-2013, 1779 adult patients (1339 males; 44.7 ± 11.6 years) underwent the pulmonary autograft procedure in 8 centres. All patients underwent prospective clinical and echocardiographic examinations annually. The mean follow-up was 8.3 ± 5.1 years (range 0-24.3 years) with a total cumulative follow-up of 14 288 years and 662 patients having a follow-up of at least 10 years.

RESULTS

The early (30-day) mortality rate was 1.1% (n = 19). Late (>30 day) survival of the adult population was comparable with the age- and gender-matched general population (observed deaths: 101, expected deaths: 91; P = 0.29). Freedom from autograft reoperation at 5, 10 and 15 years was 96.8, 94.7 and 86.7%, respectively, whereas freedom from homograft reoperation was 97.6, 95.5 and 92.3%, respectively. The overall freedom from reoperation was 94.9, 91.1 and 82.7%, respectively. Longitudinal modelling of functional valve performance revealed a low (<5%) probability of a patient being in higher autograft regurgitation grades throughout the first decade. Similarly, excellent homograft function was observed throughout the first 15 years.

CONCLUSION

The autograft principle results in postoperative long-term survival comparable with that of the age- and gender-matched general population and reoperation rates within the 1%/patient-year boundaries and should be considered in young, active patients who want to avoid the shortcomings of conventional prostheses.

Long-term results of the Ross procedure in a population-based follow-up

OBJECTIVES

The purpose of this study was to evaluate the long-term outcomes of the Ross procedure in a nationwide follow-up.

METHODS

This retrospective study involved all children treated with the Ross procedure in Finland between 1994 and 2009. The clinical records were reviewed for demographic and anatomical characteristics, Ross operation data, surgical history and status at the latest follow-up. The median follow-up time was 11.5 (range 2.4-19.2) years.

RESULTS

Fifty-one patients underwent either the Ross (n = 37) or the Ross-Konno (n = 14) procedure at a median age of 4.8 (range 0.02-16.3) years, including 13 infants (<1 year of age). The indication for the Ross procedure was aortic valve stenosis, regurgitation or both, which was observed in 29, 24 and 47% of patients, respectively. The early mortality (before hospital discharge) rate was 10% (31% in infants) and the late mortality rate 6% (15% in infants). Higher mortality was discovered in patients treated with the Ross-Konno procedure (P = 0.001). The most common cause for reintervention was pulmonary homograft stenosis. The rate of freedom from right ventricular outflow tract reintervention was 98% at 5 years, 83% at 10 years and 59% at 15 years. The rate of freedom from autograft reintervention was 98% at 5 and 10 years, and 81% at 15 years. At the latest follow-up visit, mild-to-moderate aortic root dilatation was reported in 52% of patients, and 4 patients had undergone autograft-related reinterventions. Trivial autograft valve regurgitation was commonly seen, but only 1 patient developed severe autograft regurgitation requiring mechanical valve replacement 15.9 years after the Ross operation.

CONCLUSIONS

The most common reason for reintervention after the Ross procedure in children is homograft stenosis. Aortic root dilatation and autograft valve regurgitation are relatively common but rarely lead to reinterventions before adulthood. Intraoperative complications and complex cardiac anatomy are associated with high mortality in infants undergoing the Ross-Konno procedure. In our centre, the Ross procedure has provided good long-term results in this challenging group of paediatric patients.

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.

Long-term results of the Ross operation: an 18-year single institutional experience

OBJECTIVES

The purpose of the study was to assess the 18-year outcome of the Ross operation (RO), with emphasis on survival, reoperations, and late function of the pulmonary autografts (PAs) and the right-sided pulmonary allografts.

METHODS

Between May 1995 to July 2013, 414 patients with a mean age (mean ± standard deviation) of 30.8 ± 13.1 years were submitted to an RO with the root replacement (n = 356) or the inclusion (n = 58) technique. The most prevalent aetiology was bicuspid valve (n = 206, 49.8%). Patients were divided in four groups depending on the type of allograft used on the right side. The mean follow-up was 8.2 ± 5.2 years and was 97.7% complete. In addition to longitudinal outcomes determined by means of the Kaplan-Meier analysis, log-rank test and Cox regression analysis were used to identify predictors of valve failure.

RESULTS

The early mortality rate was 2.7% and the late survival rate was 89.3% at 15 years, similar to an age- and sex-matched population. There were 22 reoperations on the PA (90.7% freedom at 15 years) and 15 on the pulmonary allografts (92.5% freedom at 15 years). The freedom rate from more than mild aortic insufficiency (AI) was 73.1% at 15 years. Thirty-three patients presented with a late root diameter >45 mm, corresponding to a freedom rate of 72.4% at 15 years. Patients with AI and a dilated annulus, especially males, are at greater risk for these complications. Among the right-sided allografts, fresh decellularized allografts showed significantly superior freedom from structural valve dysfunction.

CONCLUSIONS

The RO was associated with excellent long-term survival and low incidence of reoperations up to 15 years. Male patients with AI and dilated annulus are at increased risk for late insufficiency and root dilatation. Fresh decellularized allografts presented the best results for reconstruction of the right ventricular outflow tract.