Mid-Term Clinical Results Using a Tissue-Engineered Pulmonary Valve to Reconstruct the Right Ventricular Outflow Tract During the Ross Procedure

BACKGROUND

The Ross procedure is mainly limited by the durability of the valve prostheses used to reconstruct the right ventricular outflow tract. This study was performed to collect prospective safety and effectiveness data of the Ross procedure using a tissue-engineered heart valve to reconstruct the right ventricular outflow tract.

METHODS

Between May 2000 and February 2003, 23 patients received tissue-engineered heart valves. Two to four weeks before the Ross operation, a piece of forearm or saphenous vein was harvested to isolate, characterize, and expand endothelial cells. A pulmonary allograft (n = 11) or xenograft (n = 12) was decellularized, coated with fibronectin, and seeded with autologous vascular endothelial cells, using a specially developed bioreactor. Follow-up was performed by clinical evaluation, transthoracic echocardiography, magnetic resonance imaging, and multislice computed tomography.

RESULTS

The patient mean age was 44.0 +/- 13.7 years. Cell seeding density was 1.1 x 10(5) +/- 0.5 x 10(5) cells/cm2, with a viability of 90.2% +/- 8.9%. All patients survived the operation. One patient died during follow-up, and 1 patient required reoperation. All surviving patients are currently in New York Heart Association functional class I. Transthoracic echocardiographic evaluation of the tissue-engineered heart valve showed a mean flow velocity of 0.9 +/- 0.4 m/s at 5 years. Multislice computed tomography showed no calcification up to 5 years postoperatively.

CONCLUSIONS

Tissue-engineered heart valves showed excellent hemodynamic performance during mid-term follow-up. Decellularization of heart valves and seeding with autologous vascular endothelial cells may prevent tissue degeneration and improve valve durability.

Long-term morphological changes in a cryopreserved pulmonary valve homograft

Pulmonary homografts (PHs) are frequently used to replace the native pulmonary valve in the Ross procedure, and in the reconstruction of the right ventricular outflow tract. The case of a 25-year-old man whose PH was replaced 12 years after undergoing the Ross procedure is reported. The clinical cause of the PH failure was stenosis. Morphological studies showed cusp tissue degeneration with tears and calcification, as well as pannus growth on the flow and nonflow surfaces of the cusps and the pulmonary artery graft. The durability of this PH was likely due to a combination of low pressure on the right side of the heart and the patient's age at surgery.

Surgical strategy for the bicuspid aortic valve: tricuspidization with cusp extension versus pulmonary autograft

OBJECTIVE

The congenitally bicuspid aortic valve is the most common etiologic factor associated with clinically significant aortic stenosis and/or regurgitation in pediatric patients. Beyond infancy, surgical intervention typically involves valve repair with cusp thinning and commissurotomy or valve replacement, primarily with pulmonary autograft in the current era. An aortic valve repair technique using tricuspidization with cusp extension was introduced in 1999. This study compares the midterm clinical outcome in patients undergoing valve repair by tricuspidization with cusp extension with those receiving a pulmonary autograft (Ross).

METHODS

A retrospective study was performed on all consecutive patients with symptomatic bicuspid aortic valve disease who underwent tricuspidization with cusp extension or a Ross procedure between 1999 and 2005. In both groups, all patients were at least 1 year of age at time of the operation.

RESULTS

During this period, 21 children (median age 12.6 years, range 2.6-18 years) underwent tricuspidization with cusp extension (TCE group) and 25 children (median age 10.2 years, range 11.5 months-20.1 years) underwent the Ross procedure. Prior balloon valvuloplasty was performed in 5 (24%) of the children in the TCE group and 16 (64%) of the children in the Ross group. Prior surgical commissurotomy was performed in 4 (19%) TCE patients and in 9 (36%) Ross patients. During a median follow-up period of 36.4 months (range 2.5 months-7.4 years), 2 (10%) patients in the TCE group required valve-preserving early revision of the repair, 2 (10%) TCE patients required subsequent aortic valve replacement at 16 and 33 months, 1 (4%) Ross patient required subsequent valve repair at 5 years, and 1 (4%) Ross patient underwent cardiac transplantation at 46 months. At 36 months, the actuarial freedom from reintervention on the aortic valve or autograft was 90% in the TCE group, with 11 patients at risk, and 100% in Ross patients, with 13 patients at risk (P = .39); the freedom from moderate valve dysfunction or reintervention was 66% for TCE patients and 95% for Ross patients (P = .07). There were no deaths, and all but 1 Ross patient remain in New York Heart Association class I.

CONCLUSIONS

Reintervention rates in patients undergoing tricuspidization with cusp extension or a primary Ross procedure are similar. Valve performance in the TCE group is satisfactory at midterm follow-up, but the Ross repair appears to provide greater stability of valve function. These results suggest that repair with valve tricuspidization and cusp extension provides reliable palliation of the symptomatic bicuspid aortic valve.

In-vivo repopularization of a tissue-engineered heart valve in a human subject

A 63-year-old male with a massively calcified aortic valve showed an active lifestyle. Therefore, valve replacement was completed using the Ross procedure. During postoperative echocardiographic control, a ventricular septal defect was noted which was closed surgically. During this reoperation, a biopsy sample was taken from the wall of the tissue-engineered heart valve which was used to reconstruct the right ventricular outflow tract. A persistent monolayer of endothelial cells and host recellularization of the deeper layer was demonstrated histologically. The postoperative course was uneventful, and the patient rapidly recovered. After six years, he remains in excellent health.

The Ross operation for aortic valve disease: previous sternotomy results in improved long-term outcome

BACKGROUND AND AIM OF THE STUDY

Progressive pulmonary autograft dilatation and failure following a Ross operation continues to be of major concern. It is hypothesized that the pulmonary autograft may perform better over the longer follow up period if the Ross operation is performed as a reoperation rather than a primary operation. The basis for this hypothesis is that the epicardial and mediastinal fibrosis encountered at reoperation may inadvertently provide additional support for the pulmonary autograft during the follow up period.

METHODS

To test this hypothesis, 281 patients (mean age 24 +/- 9 years) who underwent a Ross operation over a 16-year period were retrospectively analyzed. The patient population was divided into two subgroups in whom the Ross operation was performed: (i) as the first cardiac operation, through a sternotomy incision (primary-Ross; n = 180); and (ii) after the patient had undergone a previous sternotomy (prior-sternotomy; n = 101). A recent follow up examination was achieved in 93% of patients.

RESULTS

Early and overall mortality was 2.1% and 6.4%, respectively, and there was no significant difference between the subgroups. At 12-year follow up, freedom from reoperation on the autograft, or valve-related death was 87 +/- 6% versus 71 +/- 9% in favor of the prior-sternotomy subgroup (p = 0.06). At 12-year follow up, freedom from valve-related death, or reoperation on the pulmonary autograft, or severe aortic regurgitation was 87 +/- 5% versus 71 +/- 7% (p = 0.03) in favor of the prior-sternotomy subgroup.

CONCLUSION

The results of a preliminary analysis suggest that additional benefit is accrued when the Ross operation is performed during re-sternotomy. This should encourage surgeons to attempt repair of the aortic valve during the initial surgery, with the knowledge that - if needed - the Ross operation can be performed safely at later surgery, and with possible additional benefit to the patient during the follow up period.

Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease

BACKGROUND AND AIM OF THE STUDY

The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve replacement is limited.

METHODS

Using a nationwide Dutch registry (CONCOR) and a local Belgian tertiary care center database, 17 women (age range: 18 to 45 years) with pulmonary autograft valve replacement were enrolled into the study. Twelve pregnancies were observed among five different women, including one miscarriage and one elective abortion.

RESULTS

Clinically significant (non-)cardiac complications were documented in two of 10 completed pregnancies. Complications included: (i) placental abruption necessitating Cesarean delivery at 29 weeks' gestation, further complicated by postpartum hemorrhage; and (ii) preterm premature rupture of the membranes resulting in premature delivery at 29 weeks' gestation with postpartum demise of the immature born child. Two women reported primary female infertility, but both became pregnant after hormonal substitution therapy. Four women reported irregularities of their natural menstrual cycle (menorrhagia, dysmenorrhea, polymenorrhea, oligomenorrhea, or amenorrhea).

CONCLUSION

Successful pregnancy in women with pulmonary autograft valve replacement is possible, although serious and clinically significant events occurred during gestation. Infertility and menstrual cycle disorders appear to be more prevalent.

The Ross Procedure: Clinical and Echocardiographic Follow-Up in 219 Consecutive Patients

BACKGROUND

The replacement of the diseased aortic valve with a pulmonary autograft has been shown to provide excellent hemodynamic results and to be associated with low morbidity and mortality rates.

METHODS

From 1991 to 2005, 219 patients undergoing the Ross operation were identified. All patients underwent transthoracic echocardiography at discharge and were scheduled for a yearly study thereafter. The echocardiographic study consisted of a morphologic analysis of the pulmonary autograft with measurement of end-systolic diameters at three levels: annulus, sinuses of Valsalva, and origin of the ascending aorta 2 cm above the sinotubular junction. The dynamic analysis evaluated the function of the aortic autograft and the pulmonary homograft. Maximal and mean aortic and pulmonary transvalvular pressure gradients were investigated.

RESULTS

The 30-day mortality was 1.8% (n = 4). Cardiac deaths were not related to the autograft. The 10-year actuarial survival was 95.7% +/- 2.1%. Six patients (2.8%) had grade 2 autograft valve regurgitation. No grade 3 or 4 pulmonary regurgitation was identified. At their most recent follow-up, 28 patients (13.1%) had grade 1 insufficiency of the pulmonary homograft, and 10 patients (4.6%) had a peak transvalvular gradient of 17.9 +/- 10.2 mm Hg.

CONCLUSIONS

Our current experience suggests that replacement of the aortic root with a pulmonary autograft can be safely performed in infants, children, and adults and is associated with low mortality and morbidity rates. It constitutes an elegant alternative to the use of prosthetic valves in the treatment of aortic valve diseases.

What is the proper place of the ross procedure in our modern armamentarium?

Despite nearly four decades of experience, the role of pulmonary valve autotransplantation (Ross procedure) in the treatment of aortic valve disease in adults and children continues to evolve and remains controversial. As the picture of late results has unfolded, alternating waves of enthusiasm and caution have characterized its use and have led to ongoing refinements in indications and operative technique. At present, it is seen as indispensable in the treatment of aortic valve disease in infants and small children (for whom no satisfactory replacement alternative exists and for whom growth is essential), attractive for adolescents and young adults who wish to avoid anticoagulants because of childbirth and lifestyle considerations, a reasonable option for selected adults who desire biologic solutions with potentially better durability than conventional bioprostheses, and contraindicated for the elderly and those with connective tissue disorders. Young patients with bicuspid aortic valve are the most common potential recipients, but also the most controversial, because of the risk of autograft dilatation. Optimal matching of prosthesis to patient is a clinical challenge for all caretakers involved in the treatment of valvular heart disease; this review provides guidelines to identify those patients who will benefit most from the Ross procedure, and those for whom it is inadvisable.

Predicting outcome of pulmonary valve replacement in adult tetralogy of Fallot patients

BACKGROUND

Predicting changes in right ventricular (RV) size and function after pulmonary valve replacement (PVR) is important for timely reintervention in adult tetralogy of Fallot patients.

METHODS

We analyzed the influence of pulmonary regurgitation severity and RV size and function before PVR on the outcome of RV size and function after PVR in 27 adult Fallot patients who had cardiac magnetic resonance imaging before and after PVR. RV dimensions were indexed for body surface area.

RESULTS

Pulmonary regurgitation (48% +/- 11% of RV stroke volume) was not related to RV dimensions and function before PVR. Moreover, severity of pulmonary regurgitation did not influence changes in RV dimensions after PVR. The indexed RV end-systolic volume before PVR (mean, 98 mL/m2; range, 52 to 235 mL/m2) best predicted the indexed RV end-systolic volume after PVR (mean, 59 mL/m2; range, 24 to 132 mL/m2, r = 0.78, p < 0.001) and the indexed RV end-diastolic volume after PVR (mean, 107 mL/m2; range, 70 to 170 mL/m2, r = 0.73, p < 0.001). Baseline RV ejection fraction corrected for valvular insufficiencies and shunting (21% +/- 7%) best predicted the RV ejection fraction after PVR (43% +/- 10%, r = 0.77, p < 0.001).

CONCLUSIONS

Timing of PVR should be based on indexed RV end-systolic volume and corrected RV ejection fraction rather than on severity of pulmonary regurgitation.

Chronic type A dissection in a pulmonary autograft

A 37-year-old patient presented with severe aortic valve insufficiency due to massive dilatation of the neo-aortic root (77 mm diameter) 14 years after a Ross procedure. Intraoperatively, the dilatation appeared to be caused by a localized chronic dissection of the pulmonary autograft. Surgery consisted of a modified Bentall procedure with a mechanical composite valve, with an uncomplicated postoperative course.

[Long-term results of the Ross procedure]

Aortic valve replacement with a pulmonary autograft (Ross procedure) was pioneered by Donald Ross in 1967. The advantages of the autograft valve include freedom from anticoagulation, hemolysis, and infection, optimal hemodynamic performance, and growth potential. Various materials have been used for the right ventricular outflow tract (RVOT). Currently, a cryopreserved pulmonary allograft is accepted worldwide as a useful material for this procedure. Pulmonary allografts cannot be utilized in Japan, and thus other valves and materials must be used instead. The acceptance of these procedures has been slow because of the technical demands of the operations and the inherent need for reconstruction of the RVOT, thereby placing two valves at risk. In the past 20 years, the Ross procedure has been increasingly considered for pediatric patients with a wide spectrum of congenital abnormalities.

The Ross operation: a Trojan horse?†

AIMS

The Ross operation is the operation of choice for children who require aortic valve replacement (AVR) and may also provide a good option in selected adult patients. Although the autograft does not require anticoagulation and has a superior haemodynamic profile, concern regarding autograft and allograft longevity has risen. In this light, we report the 13-year results of our prospective autograft cohort study.

METHODS AND RESULTS

Between 1988 and 2005, 146 consecutive patients underwent AVR with a pulmonary autograft at Erasmus Medical Center Rotterdam. Mean age was 22 years (SD 13; range 4 months-52 years), 66% were male. Hospital mortality was 2.7% (N = 4); during follow-up four more patients died. Thirteen-year survival was 94 +/- 2%. Over time, 22 patients required autograft reoperation for progressive neo-aortic root dilatation. In addition, eight patients required allograft reoperation. Freedom from autograft reoperation at 13 years was 69 +/- 7%. Freedom from allograft reoperation for structural failure at 13 years was 87 +/- 5%. Risk factors for autograft reoperation were previous AVR and adult patient age.

CONCLUSION

Although survival of the Rotterdam autograft cohort is excellent, over time a worrisome increase in reoperation rate is observed. Given the progressive autograft dilatation, careful follow-up of these patients is warranted in the second decade after operation.

Time-related Histopathologic Analyses of Immunologically Untreated Porcine Valved Conduits Implanted in a Porcine-to-Goat Model

This study was performed to evaluate the clinical feasibility of use of immunologically nontreated xenogenic valves, using a porcine-to-goat pulmonary valved conduit implantation model. Porcine pulmonary valve conduits were prepared with no specific immunological treatment and implanted in the right ventricular outflow tract of goats under cardiopulmonary bypass. The goats were assigned at predetermined intervals (1 day, 1 week, and 3, 6, and 12 months) as two animals for each interval. Echocardiographic examinations of the valves were performed before sacrifice. Upon retrieving the xenograft specimens, they were inspected visually and microscopically. Ten of the 12 animals survived the predetermined observation periods. Variable degrees of pulmonary regurgitation were the main findings on echocardiographic evaluations. On gross examination of the explanted specimens, all leaflets, except in one animal that prematurely died, were fairly well preserved. They were slightly shortened but free of thrombosis or vegetation. Aneurysmal dilatations of the anterior wall of the implanted pulmonary artery were observed in one of 12-month-survival animals and in another one of 3-month-survival animals. Microscopically, the three components of implanted xenografts (the pulmonary artery, valve, and infundibulum) were shown to be gradually replaced with host cells in time, while maintaining structural integrity. The nuclei of the donor tissue disappeared through pyknosis and karyolysis. In conclusion, immnunologically untreated xenogenic pulmonary valved conduits can be an alternative potential as valve substitutes with distinctive advantages of providing self-healing potential, despite a few problems observed in the current study such as occurrences of pulmonary regurgitation and sporadic cases of aortic aneurysm.

Autografts, homografts, and xenografts: overview on stentless aortic valve surgery

Stentless valves, either human (autografts, homografts) or animal (porcine xenografts), were historically among the first substitutes to be used to replace the diseased aortic valve. Forty years after those pioneering days and 15 years after revival of such valves, stentless grafts have become a mainstay in aortic surgery. Although limitations associated with the use of autografts, homografts and xenografts remain, stentless valves have profoundly improved quality of life after aortic valve/root replacement. In addition, stentless surgery has greatly advanced the understanding of aortic root anatomy, physiology and pathology among surgeons.

Ten-year experience with the Ross operation

OBJECTIVE

To evaluate the 10-year outcomes of the Ross Operation, analyzing survival rate, incidence of reoperations, and late performance of pulmonary autografts and homografts in the reconstruction of the right ventricular outflow tract.

METHODS

Two hundred and twenty seven patients with a mean age of 29.1 +/- 11 years underwent Ross operation from May 1995 to February 2005. The most prevalent etiology was rheumatic disease in 61% of the cases. Autografts were implanted using the total root replacement technique in 202 cases, with intraluminal cylinder in 20, and in the subcoronary position in 5. The right ventricular outflow tract was conventionally reconstructed with cryopreserved homografts (n = 160), with proximal extension of the homograft with pericardium (n = 41), and with decellularized homografts (n = 26). The postoperative follow-up ranged from 1 to 118 months (mean = 45.5 months).

RESULTS

Hospital mortality was 3.5%, and long-term survival was 96.9% at ten years. No episodes of thromboembolism and only two cases of endocarditis occurred. Eleven patients underwent reoperation because of problems related to the auto and/or homograft, progression of rheumatic mitral valve disease, and iatrogenic coronary insufficiency. After 10 years, 96.4% and 96.2% of the patients were free from reoperation in the autograft and homograft groups, respectively. No late autograft dilatation was observed. Reconstruction of the left ventricular outflow tract with decellularized homografts significantly reduced the incidence of gradients on late follow-up.

CONCLUSION

Late outcomes with the Ross Operation were associated with an excellent long-term survival and a low incidence of reoperations and late morbidity. We consider this procedure the best option for the surgical treatment of aortic valve disease in children and young adults.

Modified (Valsalva graft) aortic root reimplantation for successful repair of pulmonary autograft aneurysm after Ross procedure

Dilatation of the pulmonary autograft after the Ross procedure is a possible complication, necessitating aortic valve replacement. We present a case of a patient who developed pulmonary autograft dilatation and was treated successfully with valve-sparing aortic root reimplantation with a Valsalva graft.

Pulmonary homograft muscle reduction to reduce the risk of homograft stenosis in the Ross procedure

OBJECTIVE

The Ross procedure has gained increasing interest as an attractive alternative for aortic valve replacement. Despite its advantages, there is a certain risk of structural valve deterioration, especially of the pulmonary homograft as a result of shrinkage and subsequent stenosis predominantly at the muscular annulus. Theoretically, reduction of homograft muscle tissue could reduce this risk.

METHODS

From February 1996 through December 2002, a total of 238 patients (mean age 44 +/- 13.2 years) underwent the Ross procedure with the subcoronary technique with follow-up investigations before discharge and after 12 and 24 months. To estimate the importance of homograft muscle reduction within our institution-specific risk factor scale for change of transhomograft pressure gradient with time, we performed a generalized estimating equation approach, which identified homograft muscle reduction, higher body surface area in male patients, younger patient age, smaller homograft diameter, blood transfusions, and follow-up time as independent risk factors demonstrating a high beta value (-2.8638) for muscle reduction. To find out whether muscle reduction influences transhomograft pressure gradient, we compared patients with (group A, n = 39) and without (group B, n = 199) muscle reduction. The other mentioned independent risk factors were not different between groups, except for blood transfusions (group A greater than B, P < .01), indicating a negative bias for group A.

RESULTS

The maximum pressure gradient across the homograft was lower in patients with muscle reduction before discharge (4.5 +/- 2.8 mm Hg group A vs 6.2 +/- 3.8 mm Hg group B, P = .004) and after 1 (9.3 +/- 5.8 vs 13.1 +/- 8.4 mm Hg, P = .028) and 2 years (10.8 +/- 7.6 vs 13.7 +/- 7.5 mm Hg, P = .013). No significant differences were found concerning homograft insufficiency.

CONCLUSIONS

We provide some evidence that transhomograft pressure gradient can be reduced significantly within the first 2 years after operation by homograft muscle reduction. Longer term follow-up is necessary to evaluate this promising operative technique further.

Subcoronary Ross Procedure in Patients With Active Endocarditis

BACKGROUND

The Ross procedure has gained increasing interest as an attractive alternative to a prosthetic aortic valve substitute within the last decade. Because of a probably better resistance to infection as one of its advantages, the pulmonary autograft is theoretically preferable for active endocarditis.

METHODS

Between June 1994 and July 2003, the Ross procedure was performed using the subcoronary and inclusion technique in 296 patients (231 male, 65 female). Twenty patients had an active endocarditis of the aortic valve at the time of operation. A bicuspid valve was present in 10 patients. One patient had previous aortic valve surgery. Clinical and echocardiographic follow-up was complete.

RESULTS

Early mortality was 1, late mortality was 0. There were no recurrence of endocarditis and no neurologic events during the mean follow-up of 47.3 +/- 28.6 months. All patients were in New York Heart Association class I. Mean and maximum pressure gradient across the autograft was 3.5 +/- 2.0 and 6.5 +/- 3.4, respectively, with no autograft insufficiency in 15, 1+ in 4. Comparing postoperative with the last investigations, there were no significant changes of pressure gradients or grade of regurgitation. Mean and maximum homograft pressure gradients were 7.9 +/- 3.7 and 16.2 +/- 8.1 mm Hg, respectively, at last investigation; most patients had no or mild homograft regurgitation (0+, n = 13; 1+, n = 5; 2+, n = 1).

CONCLUSIONS

Native valve endocarditis can be treated with excellent results using the Ross procedure with the subcoronary and inclusion technique, with low mortality and morbidity rates and a very low recurrence rate of endocarditis.

A modified Ross operation to prevent pulmonary autograft dilatation

A modification in Ross operation is described in which the free-standing pulmonary autograft root is suspended in a Dacron prosthetic vascular jacket with a view to prevent dilatation of the neo-aortic root. In a group of 13 patients operated consecutively using this technique, there was no significant increase in the diameters of the neo-aortic root after a mean 16-month follow-up. Aortic valve function remained also satisfactory.

Degeneration of the pulmonary autograft: An explant study

OBJECTIVE

We sought to determine the histologic features of pulmonary autografts explanted after the Ross operation.

METHODS

Histologic sections of 30 explanted autografts and 8 normal heart valves were compared and semiquantitatively scored by a blinded cardiovascular pathologist.

RESULTS

Pulmonary autografts (n = 30) were explanted on average 6.1 +/- 0.6 years (median, 6.6 years; range, 0.1-11.7 years) after the Ross operation (n = 28) or removed at autopsy (n = 2). Twelve (43%) of the patients undergoing reoperation had no or negligible autograft insufficiency on early transthoracic echocardiography, 12 (43%) had grade 1 autograft insufficiency, and 4 (14%) had grade 1-2 autograft insufficiency. Valve regurgitation with root dilatation was the most common indication for reoperation after root replacement (n = 26 [93%]) and regurgitation after subcoronary implanted autografts (n = 2 [7%]). Microscopy of the autograft explants revealed normal laminar architecture and cellularity. Wall specimens were characterized by reduced and fragmented elastin and increased collagen levels (fibrosis). Medial elastin changes were associated with the presence of hypertrophic smooth muscle cells. Fibrosis was most severe in the adventitia. Intimal thickening was a common finding. Valve explants showed significant thickening caused by fibrocellular tissue on the ventricular surface and marked thickening of the free margin. An autopsy explant with normal function before death showed similar features.

CONCLUSIONS

Pulmonary autograft explants showed severe aneurysmal degeneration of the wall, which was characterized by intimal thickening, medial elastin fragmentation, and adventitial fibrosis. Valve leaflets were thickened. The presence of these features in a nonfailing explant suggests these changes represent a common mode of remodeling.

Geometric models of the aortic and pulmonary roots: suggestions for the Ross procedure

OBJECTIVE

To discuss geometric factors, which may influence long-term results relating to homograft competence following the Ross procedure, we describe the 3D morphology of the pulmonary and aortic roots.

MATERIALS

Measurements were made on 25 human aortic and pulmonary roots. Inter-commissural distances and the heights of the sinuses were measured. For geometrical reconstruction the three commissures and their vertical projections at the root base were used as reference points.

RESULTS

In the pulmonary root, the three inter-commissural distances were of similar dimensions (17.9+/-1.6mm, 17.5+/-1.4mm and 18.6+/-1.5mm). In the aortic root, the right inter-commissural distance was greatest (18.8+/-1.9mm), followed by the non-coronary (17.4+/-2.0mm) and left coronary sinus commissures (15.2+/-1.9mm). The mean height of the left pulmonary sinus was greatest (20+/-1.7mm) followed by the anterior (17.5+/-1.4mm) and right pulmonary sinus (18+/-1.66mm). In the aortic root, the height of the right coronary sinus was the greatest (19.4+/-1.9mm) followed by the heights of the non-coronary (17.7+/-1.8mm) and left coronary sinus (17.4+/-1.4mm). Measured differences between parameters determine the tilt angle and direction of the root vector. The tilt angle in the pulmonary root averaged 16.26 degrees , respectively; for the aortic roots, it was 5.47 degrees .

CONCLUSIONS

Herein we suggest that the left pulmonary sinus is best implanted in the position of the right coronary sinus, the anterior pulmonary in the position of the non-coronary sinus and the right pulmonary sinus in the position of the left coronary sinus. In this way, the direction of the pulmonary root vector will be parallel to that of the aortic root vector.

Medium-term results from pulmonary autografts after the Ross procedure in children and adolescents

INTRODUCTION

The Ross procedure is being used increasingly for the treatment of aortic valve problems in children, but the long-term prospects of the pulmonary autograft and its ability to grow continue to be controversial. This study summarises the experience of our centre from using the Ross procedure in children and adolescents.

METHODS

During the period November 1996 to March 2004, 35 children aged 3 months to 18 years (mean 10.6 +/- 5.4 years) and weighing 3.2-71 kg (mean 35.4 +/- 19.8 kg) underwent the Ross procedure for the treatment of aortic valve disease (stenosis--25, 71.4%; regurgitation--5, 14.3%; mixed--5). The majority of patients (n=26, 74.2%) had a history of aortic valve procedures. The technique employed was replacement of the aortic root with the pulmonary autograft. All patients were followed for 16-87 months (mean 37 months) with clinical and echocardiographic examinations, which were performed before discharge, 3-6 months later, and then every year.

RESULTS

Perioperative mortality was zero. There was one late (sudden) death 3 years after the procedure. Actuarial 7-year survival was 97.1 +/- 2.9% and freedom from reoperation for any reason was 100%. Two patients (5.7%) needed balloon dilatation because of pulmonary stenosis. All patients were in New York Heart Association functional class I. Haemodynamic parameters at the last follow-up examination were similar to those immediately post procedure: 12 patients (versus 11) had trivial and 3 mild aortic regurgitation. The pulmonary autograft followed the patient's body growth. The diameter of the aortic annulus increased from 19.1 +/- 3.9 mm to 21.6 +/- 2.8 mm and the diameter of the sinuses of Valsalva from 25.6 +/- 5.8 mm to 28.7 +/- 4.6 mm.

CONCLUSIONS

The Ross procedure seems to be the ideal solution for aortic valve problems in children, because of the small perioperative risk, the excellent haemodynamic results, and the potential of the autograft to grow, as shown by medium-term follow up.