Homograft Stenosis Research Articles

Midterm Results of the Ross Procedure in a Pediatric Population: Bicuspid Aortic Valve Is Not a Contraindication

Our objective was to analyze retrospectively the short- and midterm results of the Ross operation in children and the impact of bicuspid aortic valve (BAV) disease on outcome. From 1991 to 2003, 41 patients (26 male, 15 female) underwent a Ross procedure. Aortic disease was congenital in all but one. Sixty-six percent had BAV. Mean age at operation was 10.13 +/- 5.6 years (range, 0.4-18.3 years). Root replacement technique was performed in all but two (inclusion technique). There were two early deaths. Mean follow-up was 6 +/- 3.8 years (range, 0.1-14 years). The autograft (neo-aorta) presented absent, trivial, mild, and moderate regurgitation in 42%, 46%, 10%, and 2%, respectively, at latest follow-up. Root dilation was seen in 64% of the patients (mean Z-score, +3.53 +/- 0.04). Four patients (9%) required allograft replacement, two for endocarditis and two for stenosis. Allograft stenosis (gradient >20 mmHg) was detected in 44% of the remaining patients, without symptoms or the need for reintervention. Estimated freedom from allograft replacement at 5 and 10 years was 97% and 89%. Left ventricular dimensions and function were normal in all patients. No difference was found between patients with BAV and those with tricuspid aortic valves in aortic regurgitation or root dilation. BAV was not identified as a risk factor for root dilation. In conclusion, the Ross operation remains an excellent option for aortic valve replacement in children. BAV is not associated with a worse outcome and is not a risk factor for aortic root dilation at medium-term follow-up. Long-term follow-up is, however, required.

Homograft performance in 84 pediatric Ross patients – results from the Dutch-German Ross registry

Aims: The Ross operation may be the ideal aortic valve replacement in pediatric patients. However, reoperations for replacement of the homograft (HG) in the pulmonary position are inevitable. This study was conducted to determine influencing factors for the development of homograft stenosis (HS) and regurgitation (HR) in an international pediatric Ross operated cohort.

Electroporation-mediated transfer of plasmid DNA encoding IL-10 attenuates orthotopic tracheal allograft stenosis in rats

Background Electroporation has been shown to increase the efficacy of intramuscular injection of plasmid DNA, resulting in a higher level of foreign gene expression. Using this technique, we examined the effect of viral IL-10 gene transfer on the prevention of tracheal allograft stenosis in an animal model. Methods On the day of tracheal transplantation, recipient Lewis rats were intramuscularly injected with either plasmid pCAGGS-LacZ or plasmid pCAGGS-viral IL-10, followed immediately by electroporation. Tracheas from Brown Norway donors were transplanted into the backs of Lewis recipients, and the histology of the grafts were assessed 2 and 4 weeks after transplantation. Results The serum level of IL-10 peaked at 2000 pg/ml one day after injection; the level then slowly decreased, but was maintained above 1000 pg/ml until 8 days after injection. At Day 28, the airway lumina of the tracheal allografts were almost completely obliterated by fibroproliferative tissue in the control pCAGGS-LacZ-treated rats. In rats injected once with pCAGGS-viral IL-10, luminal obliteration was significantly decreased compared with the control pCAGGS-LacZ-treated rats (mean luminal opening 46.8% vs 0% p < 0.05). The loss of epithelial cells lining the airway was also decreased in the IL-10-treated group (mean epithelial coverage 42% vs 5% p < 0.05). Multiple injections with pCAGGS-viral IL-10 did not further improve the histological changes. Conclusion IL-10 gene transfer by intramuscular injection using electroporation attenuated tracheal allograft stenosis associated with mild epithelial injury.

MR Imaging of Right Ventricular Function after the Ross Procedure for Aortic Valve Replacement: Initial Experience

To prospectively assess right ventricular (RV) function after the Ross procedure by using magnetic resonance (MR) imaging. The local ethics committee approved the study and informed consent was obtained from all participants prior to enrollment in the study. Seventeen patients (15 male, two female; mean age +/- standard deviation, 19 years +/- 3.9; imaging performed 8.3 years after surgery +/- 3.2) and 17 matched controls (15 male, two female; mean age +/- standard deviation, 20 years +/- 3.9) were studied by using MR imaging. Standard velocity-encoded and multisection multiphase imaging sequences were used to assess homograft valve function, systolic and diastolic RV function, and RV mass. The two-tailed Mann-Whitney U test and the Spearman rank correlation coefficient were used for statistical analysis. Minor degrees of homograft stenosis (peak flow velocity between 1.5 and 3.0 m/sec across the homograft valve) were found in 12 of 17 patients but not in controls (P < .001). A larger RV mass was present in Ross patients than in controls (17.0 g/m(2) +/- 4.8 vs 10.9 g/m(2) +/- 5.6, P = .004). In addition, impaired diastolic RV function was found, as shown by a decreased mean tricuspid valve early filling phase-atrial contraction phase (E/A) peak flow velocity ratio (1.56 +/- 0.75 vs 2.05 +/- 0.58, P = .03). Peak flow velocity across the homograft valve correlated with RV mass (r = 0.38, P = .03) and tricuspid valve E/A peak flow velocity ratio (r = 0.39, P = .02). RV systolic function was normal in Ross patients (mean RV ejection fraction, 52% +/- 8 vs 51% +/- 5; P = .74). RV hypertrophy and RV diastolic dysfunction are frequently observed in patients after the Ross procedure, even in the absence of overt homograft stenosis. RV systolic function is still preserved.

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

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. 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. 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. 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.

Is the Ross Operation Still an Acceptable Option in Children and Adolescents?

The Ross operation is increasingly accepted as an alternative to conventional valve prostheses for children, adolescents, and young adults. We review patients younger than 20 years of age. Of 404 Ross operations done before November 2004, 60 were young patients with a median age of 12 years (range, 1 to 20 years). The pulmonary autograft technique universally was as a free root. A cryopreserved pulmonary homograft reconstructed the right ventricular outflow tract. Early postoperative complications were reentry for bleeding in 2 patients and one pacemaker insertion. No thromboembolic or hemorrhagic events occurred during the follow-up of 42 +/- 27 months. Two late deaths occurred, one from myocardial infarction after 3 months and another sudden death after 5 years, probably from critical pulmonary homograft stenosis. Echocardiographic follow-up revealed a median peak gradient of 6.3 +/- 3 mm Hg across the autograft. The median pulmonary homograft peak gradient of 19.1 +/- 13.7 mm Hg was increased to more than 30 mm Hg in 6 patients. Another 6 patients had moderate but clinically insignificant pulmonary homograft regurgitation. Altogether, 6 patients required reoperation for replacement of stenotic homografts. No autograft related reoperation occurred. Young patients with the Ross operation had good mid-term autograft function and no perioperative mortality. Factors that justify the choice of the Ross operation for young patients are the normal physiologic hemodynamics and growth of the autograft as well as freedom from anticoagulation. A 10% reoperation rate, elevated pulmonary homograft gradients, and the surgical complexity remain limiting factors.

Complications Following the Ross Procedure

Aortic valve replacement with a pulmonary autograft (ie, Ross procedure) is a technique used in selected cases for the treatment of aortic valve disease. Aware of reports describing chronic complications after the Ross procedure such as aortic insufficiency, right ventricular outlet obstruction, aortic autograft dilatation, and pulmonary allograft stenosis, cardiac magnetic resonance imaging (MRI) was performed in individuals who had a previous Ross procedure (range 2 to 10 years earlier) to determine if these complications could be visualized by MRI. This case study presents the MRI findings of 5 patients (mean age: 42.0+/-7.8 years). In each patient, complications of the Ross procedure were observed. These results suggest that cardiac MRI has the potential to become a clinically important technique for evaluating post-Ross procedure patients.

Ross Operation in the Young: A Ten-Year Experience

The Ross operation is an alternative to mechanical aortic valve replacement in the young. However, early and late complications after operation have been reported. In order to assess the role of the Ross operation in children and young adults, a 10-year clinical experience was reviewed. Ninety male and 22 female patients, aged 29 +/- 10 years (range, 6-49) underwent cross-sectional clinic and echocardiographic examination. Indication for Ross operation was aortic regurgitation in 79 patients, stenosis in 11, and mixed lesion in 22; 82 (73%) had a bicuspid valve. Endpoints of the study were survival and freedom from autograft dilatation, from autograft and homograft dysfunction, and from reoperation. There was 1 (1%) hospital and 1 late (1%) death, during an average follow-up of 5.1 +/- 1.9 years (range, 0.1-10.6). At 10 years, survival was 98 +/- 2%. Late autograft dilatation was identified in 32 (29%) patients and regurgitation in 15 (14%), 7 of whom had autograft dilatation. Ten-year freedom from autograft dilatation was 43 +/- 8% and from regurgitation was 75 +/- 8%. Multivariate analysis showed younger age (p = 0.05), preoperative aortic root dilatation (p = 0.02), root replacement technique (p = 0.03), and absence of pericardial strip buttressing (p = 0.04) to be predictive of autograft dilatation. Eleven (10%) patients required reoperation on the autograft (8 prosthetic valve replacement, 3 autograft root repair). Ten-year freedom from reoperation was 72 +/- 10% and from replacement of the autograft was 88 +/- 5%. Pulmonary homograft obstruction was identified in 6 (5%) patients, requiring homograft replacement in 1. All but 2 (2%) patients were in New York Heart Association class I, with a return to regular school grade or active employment. Late outcome for the Ross procedure is excellent in terms of survival and quality of life. Late root dilatation, autograft regurgitation, and homograft stenosis, however, show increasing prevalence with time. Technical modifications of the procedure, yearly aortic root imaging, and early reintervention on the dilated neoaortic root may further enhance the durability of the autologous pulmonary valve.

Risk Factors, Dynamics, and Cutoff Values for Homograft Stenosis After the Ross Procedure

The purpose of this study was to find homograft-related factors that might be associated with the development of stenosis after the Ross procedure, as well as to identify the natural dynamics of stenosis and find echographic cutoff values after one year of follow-up that might predict such an outcome. We followed up 71 patients (mean age, 24.27 +/- 16.57 years) who had such a procedure prospectively by transthoracic echocardiography, between 1993 and 2002. Follow-up was 55.26 +/- 29.63 months and was 90.14% complete. Homografts were harvested from heart-beating donors or cardiac transplant recipients. Allograft stenosis was analyzed and risk factors were identified by univariate, multivariate, and survival analysis methods. Stenosis was defined as a mean gradient greater than or equal to 20 mm Hg. There were two reoperations and 21 homografts were stenotic at the last follow-up, ten of which were already so at one year after the procedure. Cox regression analysis revealed a transhomograft gradient greater than 9 mm Hg at 1 year after the procedure (hazard ratio [HR] = 10.04) and homograft size (HR = 0.75) as independent predictors for stenosis. Stenosis-free survival was 85.94 +/- 4.35%, 75.51 +/- 5.55%, and 68.56 +/- 6.34 after 1, 3, and 5 years, respectively. A cutoff value of 9 mm Hg at 1 year of follow-up could predict different stenosis-free survival rates. Homograft size is the most important homograft-related factor for stenosis. Most of the increase in transhomograft gradient occurs in the first 24 months. A gradient of 9 mm Hg or more after 1 year predicts the late occurrence of stenosis.

The Ross Operation: An Evaluation of a Single Institution's Experience

Pulmonary autograft aortic root replacement was used in adults. Risk factors for aortic valve incompetence (AI) and pulmonary homograft valve stenosis are identified. From February 1991 through May 2003, 103 patients, with a mean age of 35.2 +/- 9.5 years, underwent aortic root replacement with the pulmonary autograft. Annulus reinforcement (reduction annuloplasty or use of root ring) was carried out in 45 patients. In all but 1 patient, the right ventricular outflow tract was reconstructed with a cryopreserved pulmonary homograft. Mean follow-up duration was 6.0 +/- 2.8 years (range 0.3 to 11 years). There were no hospital deaths. Overall patient survival was 98.9 +/- 1.0% at 1 year and 97.3 +/- 1.9% at 10 years. Autograft function follow-up resulted in 5 patients requiring reoperation for aortic incompetence. The univariate risk factors for aortic incompetence at discharge and during follow-up were respectively annulus reinforcement (p = 0.05) and bicuspic aortic valve (p = 0.05). Reoperation for homograft failure occurred in 1 patient. During follow-up, 24 patients (25.5%) developed homograft stenosis (gradient > 20 mm Hg). Univariate analysis indicated the diameter of the homograft (p = 0.001) as factor associated with stenosis during follow-up. Cox regression identified smaller diameter of the homograft (p = 0.001) and older age of donor (p = 0.002) as independent risk factor for the development of homograft stenosis. The Ross operation can be performed with few complications. Although both the aortic autograft and the pulmonary homograft have limited durability, this has not yet resulted in considerable reoperation rates and associated morbidity and mortality.

The Ross procedure.

The search for the ideal substitute for the aortic valve led Donald Ross to develop the pulmonary autograft concept in 1967. A historical, technical, and scientific review of this surgical option is presented together with our clinical experience. The literature is reviewed to identify the advantages and pitfalls of the Ross procedure over the last decades. We also present our clinical experience with 92 patients operated between 1997 and May 2003. Of the total, 70.65% (n = 65) were males, mean age was 29.32 +/- 11.9 years, with 20 patients under 16 and 6 patients under 10 years. Twenty-five patients (27.17%) had 31 previous interventions. There were 41 associated procedures in 34 patients. Perioperative mortality was 2.17% (two patients). Eight patients required reexploration for bleeding, one required an aortocoronary bypass, and one a permanent pacemaker. Follow-up was 97% with 2.71 patients/year (average 32.55 +/- 19.01 months). Two patients required autograft replacement, one suffered a 44-mm dilatation of the autograft, and one 13-year-old girl developed autograft endocarditis. Six patients suffered severe homograft stenosis (>50 mmHg), two were treated percutaneously, and one required replacement. Combined freedom from reintervention is 93.56 +/- 2.81% at 5 years. The Ross procedure is a mature concept with thousands of patients operated worldwide and a cumulative experience of over 30 years. Although we believe that it is the procedure of choice in the pediatric population, women in child-bearing age, and substantial subgroups of adult patients, efforts must continue to minimize the incidence of auto- and homograft failure in the long term.

Ross operation in children and young adults: the Alder Hey case series.

BackgroundThe ideal prosthesis for aortic valve replacement in children and young adults has not been found yet. In recent years there has been a renewed interest in the replacement of aortic valve with the pulmonary autograft owing to its advantages of lack of anticoagulation, potential for growth and excellent haemodynamic performance. The purpose of this study was to review our institutional experience at Alder Hey hospital with the Ross procedure in children and young adults.MethodsFrom November 1996 to September 2003, 38 patients (mean age, 13.1 ± 5.7 years) underwent the Ross procedure for various aortic valve diseases using the root replacement technique. Clinical and echocardiographic follow-up was performed early (within 30 days), 3 to 6 months, and yearly after surgery. Medical records of all patients were reviewed retrospectively.ResultsThere was 1 perioperative death. The patients were followed-up for a median interval of 36 months and up to 7 years. One patient died 3 years after surgery secondary to ventricular arrhythmia with overall mortality of 5.3%. Actuarial survival at 7 years was 94 ± 2.5% and there was 100% freedom from reoperation for autograft valve dysfunction or any other cause. Balloon dilatation was required in 2 patients for pulmonary homograft stenosis. The haemodynamics at the latest follow-up were also similar to those at the time of discharge after surgery. There was no progression in the degree of aortic regurgitation for 11 patients with trivial and 3 with mild regurgitation.ConclusionOur experience demonstrates that Ross operation is an attractive option for aortic valve replacement in children and young adults. Not only can the operation be accomplished with a low operative risk but the valve function stays normal over a long period of time with minimal alteration in lifestyle and no need for repeated operations to replace the valve as a result of somatic growth of the children.

Aortic root remodelling 13.5 years after neonatal ross operation

Objectives: On June 2nd 1989, with a body weight of 2.7kg at 12 days of age this patient was the first to survive a neonatal Ross procedure employing a 9mm diameter cryo-preserved pulmonary homograft for pulmonary valve replacement. Homograft change was required at 25 months empoying a 14mm pulmonary homograft. At 13.5 years follow-up ascending aortic diameter was 5.6cm with stable mild aortic valve regurgitation. Total ascending aortic replacement and aortic root remodelling was indicated. For moderate pulmonary homograft stenosis, replacement was indicated also.

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.

Invited commentary

Böhm and colleagues are to be congratulated for having done 250 consecutive Ross procedures in patients aged 2–67 years without a single operative death and only 3 “transiently elevated myocardial enzymes.” These exceptionally good operative results added to the fact that only one patient in their older group required pulmonary autograft replacement and none developed pulmonary homograft stenosis, which prompted the authors to conclude that “older patients fare better with the Ross procedure” than do younger ones. The authors may be correct but their conclusion is a bit premature because most patients have had only two years of follow-up and only 9 patients had 5 years of follow-up.

Hemodynamic performance at rest and during exercise after aortic valve replacement: comparison of pulmonary autografts vs. aortic homografts

The Ross procedure and aortic homografts have both been shown to have superior hemodynamic performance after valve replacement, but there have been few comparisons. Sequential Doppler echocardiograms were performed up to 5 years after aortic valve replacement in 132 patients with the Ross procedure and 111 patients with an aortic homograft (AH). Measurements included assessment of valvular regurgitation and calculations of valve effective orifice area (EOA) and mean transvalvular gradients; the same measurements were also performed at the level of the pulmonary homograft in the Ross patients as well as during maximum exercise in 20 Ross patients and 14 AH patients. Aortic valve hemodynamics were stable during follow-up for both procedures and values at 1 year showed larger indexed EOAs (1.77+/-0.45 versus 1.42+/-0.35 cm(2)/m(2), P<0.001) and lower gradients (2+/-3 versus 4+/-3 mm Hg) for the Ross procedure; similar findings were also observed during exercise (1.99+/-0.44 versus 1.36+/-0.39 cm(2)/m(2), P<0.001 and 7+/-3 versus 17+/-11 mm Hg). Prevalence and severity of aortic regurgitation were low in both groups, although 4 patients (1 Ross, 3 AH) underwent a second operation for this reason. Also, various degrees of pulmonary homograft stenosis were found in 20% of Ross patients, 4 of which underwent a second operation. Both procedures provide continued excellent hemodynamics of the aortic valve. The Ross procedure has a slight advantage, but this is somewhat counterbalanced by the deterioration of the pulmonary homograft in up to 20% of patients. Further studies aimed at clarifying longer-term outcomes as well as preventing pulmonary homograft stenosis with the Ross operation are clearly needed.

Hemodynamic Performance at Rest and During Exercise After Aortic Valve Replacement: Comparison of Pulmonary Autografts Versus Aortic Homografts

Background The Ross procedure and aortic homografts have both been shown to have superior hemodynamic performance after valve replacement, but there have been few comparisons. Methods Sequential Doppler echocardiograms were performed up to 5 years after aortic valve replacement in 132 patients with the Ross procedure and 111 patients with an aortic homograft (AH). Measurements included assessment of valvular regurgitation and calculations of valve effective orifice area (EOA) and mean transvalvular gradients; the same measurements were also performed at the level of the pulmonary homograft in the Ross patients as well as during maximum exercise in 20 Ross patients and 14 AH patients. Results Aortic valve hemodynamics were stable during follow-up for both procedures and values at 1 year showed larger indexed EOAs (1.77±0.45 versus 1.42±0.35 cm 2 /m 2 , P &lt;0.001) and lower gradients (2±3 versus 4±3 mm Hg) for the Ross procedure; similar findings were also observed during exercise (1.99±0.44 versus 1.36±0.39 cm 2 /m 2 , P &lt;0.001 and 7±3 versus 17±11 mm Hg). Prevalence and severity of aortic regurgitation were low in both groups, although 4 patients (1 Ross, 3 AH) underwent a second operation for this reason. Also, various degrees of pulmonary homograft stenosis were found in 20% of Ross patients, 4 of which underwent a second operation. Conclusion Both procedures provide continued excellent hemodynamics of the aortic valve. The Ross procedure has a slight advantage, but this is somewhat counterbalanced by the deterioration of the pulmonary homograft in up to 20% of patients. Further studies aimed at clarifying longer-term outcomes as well as preventing pulmonary homograft stenosis with the Ross operation are clearly needed.

Stentless xenografts and homografts for right ventricular outflow tract reconstruction during the ross operation

Background. Shortage of homografts prompted us to replace the transplanted pulmonary trunk with stentless xenografts during the Ross procedure. The 5-year follow-up in comparison with pulmonary homografts is presented. Methods. From April 1997 to March 2002, of 51 patients undergoing a modified Ross procedure 15 patients (age range 55 to 65 years, mean 59 ± 5) received a stentless xenograft, and 36 patients (15 to 56 years, mean 36 ± 11) a pulmonary homograft for right ventricular outflow tract (RVOT) reconstruction. Follow-up was complete for a mean of 3.1 years (range 6 to 60). Regularily performed echocardiography included determination of valve annulus, peak instantaneous gradient, leaflet performance, location of obstruction, and degree of regurgitation. Results. There was 1 late death and 1 reoperation for homograft stenosis. The homograft annulus diameter decreased by a mean of 10% (range 3 to 10 mm; p < 0.01), and peak Doppler gradient increased significantly ( p < 0.001). All patients except 1 had gradients less than 25 mm Hg. Gradients in xenograft patients were stable at a low level (6.5 ± 4.3 mm Hg to 8.8 ± 7.4 mm Hg at the latest follow-up). Mild pulmonary regurgitation was noted in 46.6% (xenografts) and 19.5% (homografts). Leaflet quality and mobility were maintained in all patients. Conclusions. Pulmonary homografts underlie a process of annular reduction after the Ross procedure, which is usually not associated with graft stenosis. Mild pulmonary regurgitation is more common in xenografts than in homografts. RVOT reconstruction using stentless xenografts represents a satisfactory treatment modality for aged patients.

Incidence, location, pathology, and significance of pulmonary homograft stenosis after the Ross operation

Incidence, location, pathology, and significance of pulmonary homograft stenosis after the Ross operation

Incidence, location, pathology, and significance of pulmonary homograft stenosis after the Ross operation.

The Ross operation has several theoretical advantages. However, concern exists regarding evolving pathology in the pulmonary homograft. Consecutive patients (n=144; mean age 31 years, range 2 months to 64 years) undergoing the Ross operation were studied between 1993 and 2000. Echocardiographic examination of the pulmonary homograft was performed immediately after surgery, then at yearly intervals for a mean interval of 48 months. Fifteen patients (mean age 37 years) in whom echocardiography revealed peak pulmonary gradients >/=30 mm Hg (mean 46+/-18 mm Hg) underwent MRI with velocity mapping in a Picker 1.5-T magnet. No patient had more than mild pulmonary regurgitation. Four patients required reoperation for rapidly progressive pulmonary homograft stenosis; in all 4, there was macroscopic and microscopic evidence of a pronounced chronic adventitial reaction, with perivascular infiltration producing extrinsic compression. Freedom from any pulmonary homograft stenosis at 7-year follow-up was 79.7%, with instantaneous hazard falling to zero after 4 years. Freedom from reoperation at 7 years was 96.7%. In those studied with MRI, there was evidence of narrowing of the whole homograft or distal suture line in 14 of 15 patients, with obvious excess surrounding tissue in 11. Mean minimum diameter and peak velocity by MRI were 11+/-2 mm and 3.2+/-0.7 m/s, respectively. Multivariate analysis of patient-, surgery-, and homograft-related variables did not reveal any significant risk factors for development of neopulmonary stenosis. Pulmonary homograft stenosis after the Ross operation is clinically important and appears to represent an early postoperative inflammatory reaction to the pulmonary homograft that leads to extrinsic compression and/or shrinkage.