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.     

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.     

Right ventricular outflow tract reconstruction with a bovine pericardial monocusp patch. Long-term clinical and hemodynamic evaluation

A bovine pericardial monocusp patch was used in 21 patients with a variety of congenital heart defects for reconstruction of obstructed right ventricular outflow tract. Two early postoperative deaths and one late death occurred, and these were unrelated to monocusp patch function. Survivors have completed a mean follow-up of 113 months (range 29 to 141 months). They are all asymptomatic, and their physical activity is unrestricted. Seventeen patients have completed more than 5 years of follow-up and, of these, 11 patients have completed more than 10 years of follow-up. Eleven patients have been reinvestigated by sequential postoperative hemodynamic and angiographic studies at mean periods of 16, 48, and 100 months. The mean peak systolic pressure gradient across the right ventricular outflow tract under conditions of normal flow was 13 +/- 2.4 mm Hg at 16 months, and it has shown no significant change when measured at intervals of up to 124 months after the operation. This lack of change suggests effective long-term relief of the outflow tract obstruction. Serial radiographic screening of all patients and angiographic studies in 11 patients disclosed no evidence of graft calcification, stenosis, or dilatation. The monocusp valve remained functional and effectively abolished or reduced pulmonary valve incompetence. In 11 patients who had residual pulmonary regurgitation, the regurgitation was mild and, up to 12 years after operation, had not resulted in any adverse clinical sequelae.     

Homologous monocuspid valve patch in right ventricular outflow tract reconstruction

BACKGROUND: In the surgical repair of tetralogy of Fallot or pulmonary atresia, pulmonary regurgitation may be detrimental in the postoperative period. We have used homograft monocuspid valve patch to prevent pulmonary insufficiency. METHODS: From September 1996 to December 1998, twenty-five patients, 4 months to 8 years of age (median 10.1 months) had homograft monocuspid valve in the procedure of right ventricular outflow tract reconstruction. The function of the monocuspid valve was assessed by echocardiogram and graded as trivial to mild, mild to moderate, moderate, and severe. We evaluated the degree of pulmonary insufficiency before discharge, at 3-6 months, and at 12 months after the operation. RESULTS: There was one hospital death due to fulminate adeno viral pneumonia. On echocardiogram, 21 patients (88%, 21/24) had no significant pulmonary insufficiency. Only one patient (4.5%) showed a moderate degree of pulmonary insufficiency. At 3-6 months, seventeen of twenty-one (81%) patients had no significant pulmonary insufficiency. There were fourteen patients who had follow-up over 1 year, and no patients showed newly developed significant pulmonary insufficiency. CONCLUSIONS: We concluded that the homograft monocuspid valve patch for right ventricular outflow tract reconstruction has provided excellent early results for the prevention of pulmonary insufficiency. However these effects are limited in duration and further close follow-up should be needed.     

Short-term hemodynamic results after right ventricular outflow tract reconstruction using a cusp-bearing transannular patch

Correction of right ventricular outflow tract obstruction remains a challenge to cardiovascular surgeons. In order to relieve this obstruction and at the same time prevent or minimize pulmonary insufficiency, we inserted a cusp-bearing transannular patch (monocusp) in 14 patients. To test this objective, we restudied 13 of these patients 0.5 to 4 months postoperatively, including quantifying pulmonary insufficiency using an accurate videodensitometric method. In all patients a degree of pulmonary insufficiency ranging from 8% to 46% of total stroke volume (mean 22.7 +/- 10.6%) was measured, and in all but one a residual right ventricular outflow pressure gradient of 2 to 22 mm Hg (mean 10 +/- 7 mm Hg) was measured. There was an inverse relation between the degree of pulmonary insufficiency and both the pressure gradient (r = -0.89) and the ratio of the pulmonary valve ring diameter to monocusp depth (r = -0.67). An ideal reconstruction of the right ventricular outflow tract obstruction, without any postoperative pulmonary insufficiency and stenosis, was not achieved by the implantation of a monocusp in the described fashion. The postoperative results were acceptable in only a few patients. A reduction of pulmonary insufficiency seems to be associated with a small residual pressure gradient as well as a relatively small cusp size. Additional studies are necessary to further improve surgical correction of right ventricular outflow tract obstruction with reproducible and predictable results.     

Long-term outcome of right ventricular outflow tract reconstruction with bicuspidalized homografts

Objective: Given the shortage of small-sized cryopreserved homografts for right ventricle (RV) to pulmonary artery (PA) reconstructions, more readily available larger-sized homografts can be used after size reduction by bicuspidalization. The aim of our study was to determine and compare function over time of standard and bicuspidalized homografts in infants younger than 12 months, including patients with a Ross or extended Ross procedure. Methods: All consecutives infants under the age of 1 year, who underwent a surgical procedure in which a homograft was placed in the RV-PA position between January 1994 and April 2009, were included. Prospectively collected data from serial, standardized echocardiography from all patients were extracted from the database, and hospital records were retrospectively reviewed. Results: A total of 40 infants had a valved homograft conduit placed in the RV-PA position. In 20 of those patients, a bicuspidalized homograft was used. Twelve patients underwent a Ross procedure, of whom seven had an additional Konno-type aortic annulus enlargement. Median follow-up was 146 months (interquartile range (IQR), 117–170; total patient years: 178) in the group with standard use of the homograft and 95 months (IQR, 11–104; total patient years: 78) in the group with bicuspidalized conduits. Freedom from re-intervention (re-operation or percutaneous) was not different in the standard and bicuspidalized groups for all and Ross or Konno–Ross procedures (Tarone-Ware, p = 0.65 and p = 0.47, respectively). Consecutive echocardiographic maximum velocities in the right ventricular outflow tract were similar in the standard and bicuspidalized groups. Conclusion: When proper sized cryopreserved homografts for placement in the RV-PA position in Ross, Konno–Ross, and other procedures in infants under the age of 1 year are not readily available, bicuspidalized homografts provide an acceptable alternative.     

同种带瓣管道应用的远期效果

目的　评价同种带瓣管道应用后的远期效果。方法　1988年1月至1997年12月的10年间应用同种带管道瓣治疗165例多种复杂先天性心脏病(先心病)，其中主动脉带瓣管道136例、肺动脉带瓣管道29例。病人年龄1.3～22.0岁，平均7.6岁。体重9.5～58.0kg，平均22.0kg。管道直径17～22mm，平均19mm。结果　术后早期（30d内）死亡40例，死亡率为24%。术后随访10个月～12.1年，平均(37.0±8.6)个月。病人术后5、10年生存率分别为94.6%、83.8%，带瓣管道完好率分别为83%、58%。结论　应用同种带瓣管道治疗复杂先心病，远期疗效比较满意。     

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.     

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.     

Pulmonic regurgitation and reconstruction of right ventricular outflow tract with patch. An experimental study

Twenty-five dogs were divided into three experimental groups. In each animal of Group I (10 dogs), one pulmonary valve leaflet was resected and a monocusp-bearing bovine pericardial patch was sewn into the right ventricular outflow tract. The monocusp was retracted to the patch with plicating sutures, and when the sutures were removed the monocusp became functional. In each animal of Group II (10 dogs), an incision was made in the right ventricular outflow tract along the anterior pulmonary valvular commissure and a bovine pericardial patch of adjustable width (one half, one, or one and one half times the diameter of the pulmonary valve ring) was sewn into the incision. Group III (five dogs) was the control group. During each situation of altered pulmonary valve function, in each experimental animal, the pulmonary blood flow and intracardiac pressures were measured. Pulmonary regurgitation was expressed regurgitant fraction (retrograde flow divided by net forward flow). We reached the following conclusions: In all situations where pulmonary incompetence was created, the regurgitant fraction was related directly to the width of the patch and was usually not more than half of the net forward flow when the width of the patch was less than one and a half times the pulmonary valve ring diameter. Regurgitant fraction was about half of net forward flow when one leaflet had been excised. The index of pulmonary artery diastolic pressure minus right ventricular end-diastolic pressure was sensitive and bore an inverse relationship to the degree of pulmonary regurgitation. An accurately placed monocusp-bearing patch restored pulmonary valve competence after excision of a cusp. In treating patients, we are encouraged to preserve as much pulmonary valve function as possible.     

Long-term results after reconstruction of the left ventricular outflow tract by aortoventriculoplasty

BACKGROUND: Aortoventriculoplasty is an established method of reconstruction of complex left ventricular outflow tract (LVOT) obstruction by insertion of a mechanical valve prosthesis after patch enlargement of the LVOT. Little data exist with respect to long-term outcome. METHODS: Between March 1991 and June 2001, 24 patients with a median age of 10.7 (range, 2.1 to 66) years underwent aortoventriculoplasty, which was performed as a primary procedure in 4 and as a secondary intervention in 20 patients. On follow-up, all patients were restudied with an actual prospective evaluation. Data were statistically analyzed using a paired t test. RESULTS: There was one early death from low cardiac output. Four patients had to be reoperated on for bleeding. All 23 postoperative survivors were followed up for 63 (range, 12 to 123) months. Aortic anulus size of 14 (7 to 19) mm could be significantly enlarged to a size of 24 (19 to 27) mm for insertion of a mechanical valve prosthesis (p < 0.001). Blood flow velocity across the LVOT significantly decreased to 1.8 (1.3 to 2.9) m/s (preoperative, 4.1 [2.7 to 5.8] m/s) (p < 0.001). There were no late deaths. One patient underwent late repair of a paraprosthetic leak. On follow-up, there was no hemorrhage related to anticoagulation observed, but there was one minor thromboembolic complication. Relief of LVOT obstruction and good function of the valve prostheses could be demonstrated in all patients. CONCLUSIONS: Aortoventriculoplasty is an easily applicable, low-risk procedure for the effective relief of complex LVOT obstruction, and provides excellent long-term results.     

Long-term outcome of right ventricular outflow tract reconstruction using a handmade tri-leaflet conduit.

OBJECTIVE: Since 1985, we have implanted handmade tri-leaflet conduits made of heterologous pericardium or expanded polytetrafluoroethylene (ePTFE), as an alternative to homograft for right ventricular outflow tract reconstruction. This report assesses the long-term outcome of these prostheses. METHODS: From 1985 to 2003, 216 handmade tri-leaflet conduits were implanted in 191 patients. Forty-two patients had previous conduit repairs. The mean age at operation was 8.1+/-7.7 years (range: 15 days-44 years). The underlying diagnoses were pulmonary atresia with ventricular septal defect in 83 patients, atrioventricular discordance in 36, transposition of the great arteries in 26, double outlet right ventricle in 14, and truncus arteriosus in 17. Whole heterologous pericardial tri-leaflet conduits were implanted in 169 patients, in the early series (porcine: 85; equine: 58; bovine: 26); bovine pericardial conduits containing ePTFE leaflets were implanted in 26 patients since 1996; whole ePTFE tri-leaflet rolls were employed in the most recent 21 patients. The conduit size was 21.1+/-3.1mm (range: 12-27 mm), 147.4+/-21.4% (range: 82.6-202.6%) of the anticipated diameter of the pulmonary valve. Follow-up was complete. RESULTS: There were 28 early deaths and 24 late deaths. The indication for conduit replacement was a peak instantaneous pressure gradient of greater than 50 mmHg. Sixty-five conduits required reoperation for conduit obstruction at 8.6+/-3.3 years after implantation. The freedom from reoperation at 5, 10, and 15 years was 93.9+/-1.9, 61.4+/-4.5, and 35.5+/-5.6%, respectively. Patients with smaller conduit size and young age at operation were predisposed to reoperation. None of the 47 ePTFE tri-leaflet conduits developed significant obstruction. The freedom from important pulmonary valve regurgitation (PR) as assessed by echocardiography was 68.3+/-3.7% at 5 years, 33.0+/-4.5% at 10 years, and 21.6+/-4.9% at 15 years. No patient required reoperation due to PR or right ventricular dysfunction. CONCLUSIONS: Handmade tri-leaflet conduits provide a reliable alternative for RVOT reconstruction in children, yielding as good a long-term outcome as do homografts. Longer follow-up is needed to determine how well ePTFE leaflets will fare.     

Reoperation cases long after Rastelli operation: right ventricular outflow tract reconstruction by means of a xenograft non-valved patch

Two cases who underwent the new procedure of treatment for extracardiac conduit stenosis after Rastelli operation are reported. They had undergone Rastelli operation 11 and 12 years ago. Because of stenotic Hancock valve of the conduit, they were reoperated. A longitudinal incision was made anteriorly over the conduit and the conduit was dissected free. The sides and posterior half of the conduit bed were preserved. The roof of the new right ventricular outflow tract was formed using a xenograft pericardium patch. Their postoperative courses were smooth.     

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.     

One-stage unifocalization and palliative right ventricular outflow tract reconstruction

We report a successful case of one-stage unifocalization concomitant with palliative right ventricular outflow tract reconstruction for pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries and central pulmonary arterial absence. Through a median sternotomy, one-stage unifocalization was accomplished using autologous pericardial conduit and no prosthetic material. To achieve an adequate pulmonary blood flow, the right ventricular outflow tract was reconstructed so that it would be 70% of the normal pulmonary annular diameter, while the ventricular septal defect was left open. One-stage unifocalization concomitant with palliative right ventricular outflow tract reconstruction is considered to be a good surgical option for selected patients with these diseases.