Medtronic freestyle valves in right ventricular outflow tract reconstruction

BACKGROUND: Various pulmonary valve substitutes, with their inherent limitations, have been used in children and young adults. We chose the Medtronic Freestyle (Medtronics, Minneapolis, MN) valve because of its excellent hemodynamics, known durability in adults, and design features that allow modifications during implantation. METHODS: Over a 3 1/2 year period the Freestyle valve was implanted in 47 patients age 2 to 58 years (mean 14.2, median 12.0) in the pulmonary position. All patients had pulmonic stenosis and(or) insufficiency from previous operations for tetralogy (27), pulmonary atresia (6), truncus (4), or other diagnosis (10). The indication for surgery was pure pulmonary insufficiency in 11 patients, pulmonic stenosis in 3, and mixed stenosis and insufficiency in 33. Root replacement technique was used with additional enlargement of the pulmonary artery branches in 10 patients. RESULTS: Intraoperatively, one patient sustained a right ventricle tear and one a circumflex coronary artery injury during the dissection. There was one postoperative death. Two patients developed late subvalvular pannus formation, one of whom required reoperation. One patient was found to have an echo gradient of 95 mm Hg due to decreased leaflet motion and underwent cardiac catheterization at which the peak systolic gradient was determined to be 50 mm Hg. He has not required reintervention during his 3 1/2 years of follow-up. The remaining 43 patients have minimal gradients or insufficiency. All surviving patients are in New York Heart Association (NYHA) Class I. CONCLUSIONS: The Medtronic Freestyle valve is an attractive alternative for RVOT (right ventricular outflow tract) reconstruction in children. It is readily available, versatile, and has excellent hemodynamic characteristics. Although long term follow-up is not yet available, longevity of this prosthesis, and freedom from complications, will hopefully be superior to valves with stents.     

PTFE monocusp valve reconstruction of the right ventricular outflow tract

BACKGROUND: Transannular patching of right ventricular outflow tract obstructive (RVOTO) defects results in pulmonary insufficiency (PI). Biologic monocusp valves (MO) can prevent acute PI but are prone to early degeneration and progressive regurgitation. Polytetrafluoroethylene (PTFE, 0.1 mm) MO leaflets demonstrated favorable characteristics in animal studies, and the technique was applied to a variety of RVOTO anomalies. METHODS: From June 1990 through June 1999, 158 patients underwent either PTFE MO RVOT reconstruction (n = 115 patients; 120 implants) or nonvalved transannular repair (TA) repairs (n = 43 patients; 5 subsequent MO implants) at our institution. Standard MO construction techniques and TA repairs were utilized. Intraoperative, postoperative, and echocardiographic data with a mean interval of 2.6 years (range 6 months to 8 years) were used in retrospective fashion to compare clinical outcomes. In addition, PTFE monocusp valves beyond 6 months postimplant underwent echocardiographic analysis of MO function and durability. RESULTS: There were 4 early (MO-3, TA-1) and no late deaths. Overall, perioperative complications were not significantly different between MO and TA groups, nor were total hospitalization days (9.1 versus 10.7, p = 0.24). However, a significant difference in intensive care unit (ICU) utilization (3.6 versus 5.8 days, p = 0.03) favored MO patients. Patients with tetralogy of Fallot (TOF) and ventricular septal defect/pulmonary atresia (VSD/PA) undergoing the MO implant demonstrated a trend toward improved survival (p = 0.08) when compared to TA repairs. Intraoperative PI was graded mild in the MO group and moderate-severe in the TA group (p = 0.003). Progressive MO regurgitation occurred (mild-moderate) but remained significantly less than the transannular patch repairs (p < 0.05). CONCLUSIONS: Utilization of a PTFE MO valve prevents short-term and significantly reduces midterm PI. It is inexpensive, easy to construct, and demonstrates no evidence of stenosis, calcification, or embolization. Despite longer cardiopulmonary bypass and ischemic times, it reduces ICU stay and, in both TOF and VSD/PA patients, decreases operative morbidity and mortality.     

Carpentier edwards porcine valved conduit for right ventricular outflow tract reconstruction

Abstract Background: The optimal conduit for right ventricular outflow tract (RVOT) reconstruction is uncertain, with varying degrees of longevity reported for pericardial, homograft, and xenograft valves utilized in this position. Methods: A retrospective review of children and adults with congenital heart disease who underwent RVOT reconstruction with the Carpentier Edwards? (CE) porcine valved conduit was conducted from 2001 to 2009 at the University of Rochester and SUNY Upstate Medical Centers. Clinical data were analyzed for each subject according to conduit size, and all of the Doppler derived transconduit gradients from postoperative echocardiograms were analyzed. Results: Two hundred and eighteen patients received a single CE conduit for RVOT reconstruction with conduit size ranging from 12 to 30 mm. Perioperative mortality was 1.8% (4/218). Follow‐up data were available for 95% of subjects with duration of follow‐up ranging from 1 to 9 years. The increase in transconduit gradient over time was inversely proportional to conduit size. For the entire series, freedom from reoperation was 70.3% at 8.2 years. Patients receiving 25 and 30 mm conduits demonstrated no gradient development over this period of follow‐up. Conclusions: In this series, the CE conduit showed excellent longevity at intermediate term follow‐up, with slower progression of conduit stenosis as measured by RVOT gradient change compared with previous reports. (J Card Surg 2011;26:643‐649)     

Options for right ventricular outflow tract reconstruction

The popularity of the Ross operation has drawn attention to the need for a satisfactory replacement of the excised pulmonary valve and artery. Although living autogenous tissue is desirable, it has not been possible to manufacture a satisfactory living conduit, and pulmonary homografts have provided a satisfactory long-term solution. Now, with the increasing shortage of homografts, a number of alternative options have to be considered. The most useful and readily acceptable replacement is a porcine pulmonary xenograft, which is now commercially available. Other prospects for future consideration relate to the use of transgenic pig tissue and developing techniques of tissue engineering. In emergency conditions where a valve conduit is unavailable, a temporary solution is to use a simple tube of autogenous pericardium.     

Reoperative homograft right ventricular outflow tract reconstruction

BACKGROUND: Homografts are implanted in the right ventricular outflow tract (RVOT) of children, with the knowledge that reoperation might be required. We reviewed 14 years of homograft RVOT reconstruction to assess the feasibility of homograft replacement and to determine risk factors for homograft survival. METHODS: From February 1985 through March 1999, 223 children (age 5 days to 16.9 years) underwent primary RVOT reconstruction with an aortic or pulmonary homograft. Of these, 35 patients underwent homograft explant at the implanting hospital with insertion of a second homograft from 2 months to 13.3 years after the first implantation. The primary operation and reoperation patient groups were compared with regard to incidence of early death, late death, homograft-related intervention without explant, and homograft explant. RESULTS: Actuarial survival and event-free curves for initial and replacement homografts were not significantly different. Univariable analysis was performed for the following risk factors: weight (p < 0.0001), age (p < 0.003), homograft diameter (p < 0.0001), homograft type (p < 0.01), surgery date (not significant [NS]), gender (NS), Blood Group match (NS), and type of distal anastomosis (NS). Multivariable analysis of significant univariable risks revealed small homograft diameter to be a significant risk factor (p < 0.001) for replacement. CONCLUSIONS: The RVOT homografts eventually require replacement. Patient and homograft survival for replacement homografts is similar to primary homografts. Reoperative homograft RVOT reconstruction is possible, with reasonably low morbidity and mortality.     

Pericardial tissue valves and Gore-Tex conduits as an alternative for right ventricular outflow tract replacement in children

BACKGROUND: There is still no perfect conduit for reconstruction of the right ventricular outflow tract (RVOT) in children. Homografts are not always available in the appropriate size, and degenerate in a few years. This study evaluates the pericardial valve with Gore-Tex conduit as an alternative for RVOT construction. METHODS: From January 1, 1993, to September 30, 1999, a pericardial tissue valve was inserted in all patients undergoing RVOT reconstruction or pulmonary valve replacement (PVR) who were large enough to accommodate a tissue valve. In patients without a native main pulmonary artery, a new technique was used to construct an RV-PA conduit out of a flat sheet of Gore-Tex, as Dacron frequently leads to stenosis. Data were collected by retrospective review, follow-up echocardiograms, and assessment by a single cardiologist. RESULTS: There were 48 patients, 22 undergoing a PVR alone and 26 a RV-PA valved Gore-Tex conduit. Diagnosis included tetralogy of Fallot (n = 25); truncus arteriosis (n = 9); ventricular septal defect with PA (n = 5); DORV (n = 4); D-TGA with PS (n = 2); and 1 each IAA with sub AS, VSD with PI, and PS s/p Ross procedure. Patient age ranged from 3 to 33 years and 98% were reoperations. The valve sizes ranged from 19 to 33 mm and the median hospital length of stay was 4 days. There were 2 (4.2%) perioperative and 1 (2.1%) late deaths, none related to the valve or Gore-Tex conduit. At a follow-up of 15 to 86 months (mean 43 +/- 16 months), all remaining 45 patients are New York Heart Association class I, all valves are functional, and no patient has required valve or conduit replacement or revision; more importantly, echocardiogram revealed no significant valve or conduit stenosis (mean gradient 16 +/- 8 mm Hg) and no evidence of regurgitation or structural degeneration. CONCLUSIONS: A pericardial tissue valve and Gore-Tex conduit provides a reliable alternative for RVOT reconstruction in pediatric patients. It is readily available, molds in the limited retrosternal space, and has outstanding intermediate results with no evidence of failure or deterioration up to 7 years after insertion.     

Apico-aortic conduits in children with severe left ventricular outflow tract obstruction

BACKGROUND: Infrequently, congenital heart defects are complicated by left ventricular outflow tract obstruction (LVOTO) not amenable to conventional reconstruction. Apico-aortic conduits provide a means of palliating such patients until definitive repair is possible. The purpose of this study was to review a single institution's current experience with apico-aortic conduits. METHODS: The medical records of pediatric patients receiving apico-aortic conduits were reviewed. Demographics, operative techniques, preoperative and postoperative physiologic variables, morbidity, mortality, and functional class were recorded. Off-pump and on-pump procedures were categorized for comparison. RESULTS: Ten cases of apico-aortic conduits for left ventricular outflow tract obstruction were identified. Indications included congenital aortic stenosis, aortic atresia, and subaortic stenosis. Six procedures were performed off-pump and four required median sternotomy with cardiopulmonary bypass as necessitated by concomitant procedures. There was one operative death. The remaining patients demonstrated hemodynamic improvements and are all alive to date. One patient required conduit valve replacement. All patients are in New York Heart Association classification I or II at the time of last follow-up. CONCLUSIONS: Apico-aortic conduits provide a safe and effective treatment alternative for select cases of left ventricular outflow tract obstruction. Off-pump techniques are feasible in the majority of cases. This valuable adjunct should be considered whenever conventional repair of left ventricular outflow tract obstruction is considered prohibitive.     

An expanded polytetrafluoroethylene-autologous aortic hybrid valve for right ventricular outflow tract reconstruction in the Ross procedure

Although the Ross procedure is a well-established approach to aortic valve disease in pediatric patients and young adults, there still is no ideal method of right ventricular outflow tract (RVOT) reconstruction, especially in children. To achieve improved RVOT reconstruction with long-term valve function and growth potential, we have developed a hybrid valve which combines the autologous aortic valve and expanded polytetrafluoroethylene (ePTFE) valves. The posterior wall of RVOT was reconstructed using the autologous aortic wall with a noncoronary cusp, and the anterior wall was reconstructed using a patch made of bovine pericardium or ePTFE with bicuspid ePTFE valves. We implanted hybrid valves in 14 patients (age 5-18 years). During the follow-up period (2.4-8.8 years), there were no mortalities or morbidities, and no patients required reoperation. Echocardiography showed no significant stenosis and regurgitation, and preserved valve motion in all patients. The z-value of the diameters of the pulmonary annulus in early and late follow-up was -1.4 and -1.8, respectively, the difference not being significant. Creation of a hybrid valve was associated with excellent mid- to long-term results. Given its theoretical growth potential, we speculate that this valve could be a good choice for RVOT reconstruction in the Ross procedure, especially for young children.     

Aortic root replacement with the freestyle stentless porcine aortic root bioprosthesis

Background. Stentless porcine prosthetic valves offer several advantages over traditional valves. Among these are superior hemodynamics, laminar flow patterns, lack of need for anticoagulation and perhaps improved durability.

Methods. One hundred and twelve patients were operated on from September 17, 1992 to April 13, 1998 as part of a multi-center worldwide investigation. All patients received a total aortic root replacement. Patients were evaluated postoperatively at discharge, 3 to 6 months, and yearly by clinical exam and color flow Doppler echocardiography.

Results. There were 4 deaths either in the hospital or within 30 days after surgery for an operative mortality of 3.6%. No patients experienced structural valve deterioration, non-structural valve deterioration, paravalvular leak, unacceptable hemodynamic performance, or postoperative endocarditis. The linearized rates for survival and thromboembolic complications at 5 years were 82.8% and 90.5% respectively. Excellent hemodynamic function is demonstrated by very low gradients, large EOA, and an exceedingly low incidence of any aortic regurgitation.

Conclusions. The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root for aortic valve and aortic root pathology. Root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Early and intermediate results are encouraging, but further follow-up is needed to determine valve durability.     

Fifteen years' experience with the aortic homograft: the conduit of choice for right ventricular outflow tract reconstruction

Ninety-seven patients with pulmonary atresia underwent right ventricular outflow tract reconstruction using a homograft conduit. There were 46 hospital deaths (47%). Hospital mortality was significantly related to irreversible pulmonary hypertension (p less than 0.001) and thoracotomy for ligation of bronchial collaterals (p less than 0.01). The actuarial survival was 37 +/- 7% at 10 years. Sixteen patients undergoing recatheterization at a mean of 6 years had a mean transconduit gradient of 24 +/- 15 mm Hg. Obstructed conduits (i.e., with a gradient of greater than 50 mm Hg) were replaced in 3 patients, corresponding to 13 +/- 8% at 10 years. In each instance, the obstruction was due to neointimal hyperplasia in the Dacron tube rather than calcification of the homograft valve. The fresh, antibiotic-sterilized aortic homograft is the conduit of choice for right ventricular outflow tract reconstruction. The valve itself appears more resistant to calcification than its xenograft counterpart, and the absence of Dacron removes the problem of fibrinous peel obstructing the conduit. We now construct a tube of autologous pericardium to increase the length of the conduit and avoid complementary thoracotomy for ligation of bronchial collaterals.     

Left atrial appendage insertion for right ventricular outflow tract reconstruction

BACKGROUND: The left atrial appendage (LAA) may serve as an alternative to the pulmonary arterial wall for right ventricular outflow tract (RVOT) reconstruction without an extracardiac conduit. METHODS: Five consecutive patients with pulmonary atresia or severe stenosis underwent corrective (n = 4) or palliative (n = 1) RVOT reconstruction using an LAA insertion. Surgery was performed to treat tetralogy of Fallot, double-outlet right ventricle, or transposition of the great arteries. By inserting the LAA into the obstructed portion, the width of the posterior wall of the RVOT was 20 mm or more. The anterior half of the RVOT was then augmented with pericardial patch. RESULTS: There were no early or late postoperative deaths, and no major complications (arrhythmias, thrombo-embolic episodes, infective endocarditis, need for reoperation). The postrepair systolic right ventricular-to-systemic arterial pressure ratio was 0.61 +/- 0.26. Color Doppler flow mapping revealed that the reconstructed RVOT was nonobstructive and had nonturbulent flow. No thrombus or pseudoneointimal formation was observed in the RVOT. CONCLUSIONS: LAA insertion in the RVOT is an effective alternative to, or adjunct of, direct anastomosis. It offers several advantages, including fewer early and midterm complications and avoiding the use of an extracardiac conduit.     

Polytetrafluoroethylene monocusp valve technique for right ventricular outflow tract reconstruction

Nonvalve transannular patch repair of right ventricular outflow tract obstructive (RVOTO) defects results in pulmonary insufficiency, which can contribute to early postoperative right ventricular dysfunction. In both animal and clinical studies, monocusp valves provide perioperative RVOT competence and improved right ventricular functional characteristics. In these reports, monocusp leaflet construction with 0.1-mm polytetrafluoroethylene (PTFE) appeared equal, or superior, to biologic monocusp valves. Construction of the polytetrafluoroethylene monocusp valve is an inexpensive and straightforward way to create a competent RVOT in a variety of RVOTO anomalies. Based on our clinical experience, it effectively prevents short-term and significantly reduces midterm pulmonary insufficiency without evidence of stenosis.