Makoto Ando

Ten-year experience with handmade trileaflet polytetrafluoroethylene valved conduit used for pulmonary reconstruction

OBJECTIVE The objective of this study was to investigate the results of handmade polytetrafluoroethylene trileaflet conduits implanted in the pulmonary position since 1997. METHODS One hundred thirty-nine patients underwent pulmonary reconstruction with a polytetrafluoroethylene conduit. Conduit function was investigated by means of review of serial echocardiographic studies. RESULTS Mean age and body weight were 12.7 +/- 12.0 years and 30.9 +/- 20.6 kg. Mean size of the conduit was 21.0 +/- 3.8 mm (12-28 mm). The z score of the conduit was +0.5 +/- 0.8 for patients older than 15 years (n = 43), +1.2 +/- 0.7 for patients 5 to 15 years old (n = 48), and +2.4 +/- 0.5 for patients younger than 5 years (n = 48). Conduits were used for the Ross procedure in 21 patients and for repair of complex congenital heart disease in 118 patients. There were 3 (2.2%) in-hospital deaths and 1 late death. Four patients required conduit explantation because of pulmonary artery distortion at a distal anastomotic site (interval, 1.2 years), infection of the polytetrafluoroethylene valve (interval, 1.6 years), midportion angulation of the conduit (interval, 4.9 years), and conduit compression by the ascending aorta (interval, 5.4 years). Estimated freedom from conduit explantation was 88.0% +/- 6.8%, and pulmonary insufficiency was less than or equal to mild in 75.0% at 10 years. All valves maintained their motion, and the mean estimated pressure gradient across the conduit was 19.6 +/- 11.9 mm Hg at 5 years and appeared to reach a plateau thereafter. The pressure gradient across the conduit was 14.2 +/- 8.0 mm Hg at 3 years (P = .0127) and 18.1 +/- 7.5 mm Hg at 7 years (P = .0208). CONCLUSIONS Polytetrafluoroethylene conduits represent a valid option and reliable alternative to homograft and xenograft implantation for pulmonary reconstruction.

Effectiveness of Carvedilol for Congestive Heart Failure that Developed Long after Modified Fontan Operation

We report a case of a patient with severe heart failure after Fontan procedure in whom carvedilol was very effective. A 27-year-old man had intractable congestive heart failure due to severe ventricular dysfunction after Fontan operation. Central venous pressure was elevated to 29 mmHg. A right-to-left shunt was noted across a large collateral vessel between the innominate vein and the pulmonary vein. He was administered carvedilol (initial dose, 2 mg/day; maximum dose, 30 mg/day). Cardiac catheterization performed 1 year after carvedilol administration revealed a decrease in atrial pressure and improvement of ventricular function. He underwent a conversion operation to total cavopulmonary connection (TCPC) and ligation of a collateral vein communicating with the innominate and pulmonary veins. Carvedilol may be a legitimate treatment before TCPC conversion or heart transplantation for the high-risk group of patients with a failed Fontan circulation.

Efficacy and safety of carvedilol for heart failure in children and patients with congenital heart disease

There have been few reports describing the use of carvedilol in children or patients with congenital heart disease. Therefore, its optimal regimen, efficacy, and safety in these patients have not been adequately investigated. Subjects were 27 patients with two functioning ventricles, for whom carvedilol was initiated (from December 2001 to December 2005) to treat heart failure. All patients had failed to respond to conventional cardiac medication. They consisted of 12 males and 15 females, aged 23 days to 47 years (median age: 2 years). Heart failure due to ischemia (myocardial infarction, intraoperative ischemic event) or due to myocardial disease (cardiomyopathy, myocarditis), and heart failure with atrial or ventricular tachyarrhythmia represented 70% of all cases. Carvedilol was initiated at a dose of 0.02–0.05 mg/kg/day, which was increased by 0.05–0.1 mg/kg/day after 2 days, 0.1 mg/kg/day after 5 days, and 0.05–0.1 mg/kg/day every month thereafter with a target dose of 0.8 mg/kg/day. This study retrospectively assessed the efficacy and adverse reactions based on changes of symptoms, cardiothoracic ratio (CTR), left ventricular ejection fraction (LVEF), and human atrial natriuretic peptide (hANP)/b-type natriuretic peptide (BNP) blood levels. The mean follow-up period was 10.2 months (range: 1–46 months). Twenty-six (96.3%) patients showed improvement in symptoms and were discharged from the hospital. However, the remaining one patient failed to respond and died. Significant cardiovascular adverse reaction was seen in none of the patients. The mean CTR decreased from 61.8% ± 5.3% before treatment to 57.6% ± 7.4% after treatment (P < 0.05, n = 25), and the mean LVEF improved from 41.4% ± 23.1% to 61.1% ± 10.1% (P < 0.05, n = 10), respectively. Mean hANP and BNP levels showed a decrease from 239.1 pg/ml to 118.3 pg/ml and a significant decrease from 437.9 pg/ml to 120.5 pg/ml, respectively (P < 0.05, n = 10). Improvements in these data were also demonstrated when analyzed individually among the pediatric group (aged younger than 18) and the congenital heart disease group. Initiation of carvedilol at a lower dose with more gradual dose escalation, compared with previously reported regimens, might have efficacy with low incidence of adverse effects in pediatric patients and patients with congenital heart disease. Carvedilol may be effective in treating heart failure in children due to ischemia, myocardial disease, and complicated by tachyarrhythmia.

Variations of atrioventricular septal defects predisposing to regurgitation and stenosis.

BACKGROUND An additional malformation of the atrioventricular valve is occasionally encountered in patients with complete atrioventricular septal defect, and this may compromise accurate correction. METHODS We reviewed 138 patients undergoing complete repair with two-patch technique between 1992 and 2008. The mean age was 7.1 + or - 8.3 months, and the mean body weight was 5.1 + or - 2.1 kg. Preceding pulmonary arterial banding was performed in 23 patients. RESULTS The operative record delineated additional malformations of the atrioventricular valve that posed difficulty in positioning the ventricular septal patch and in accurately approximating the cleft in 45 patients. Of them, four types (n = 40) were associated with increased incidence of postoperative left valvular problems (moderate or worse regurgitation or stenosis). These included abnormalities of the papillary muscles that accompanied hypoplastic mural leaflet or incomplete opening of one commissure in (n = 15; p = 0.0054), dense insertion of the chords of the superior leaflet that obscured the right side of the ventricle septal crest in (n = 13; p = 0.0004), double orifice valve (n = 7; p = 0.0225), and severe length disparities of the cleft that resulted from either disproportional size of superior against inferior leaflets or redundant chord supporting the left extremity of one of these leaflets (n = 5; p < 0.0001). Neither greater age at operation (more than 6 months) nor preceding pulmonary arterial band reduced the incidence of left valvular problems in the malformation group. CONCLUSIONS An individualized technique is required to maintain coaptation of the atrioventricular valve, but in many cases, they are not completely correctable. Deferring complete repair by placing a pulmonary arterial band did not reduce left valvular problems.

Single ventricle repair in children with Down's syndrome.

ObjectiveThere is a paucity of information regarding appropriate management of children with Down’s syndrome and a functional single ventricle. We report the results of bidirectional superior cavopulmonary shunts in six patients with Down’s syndrome with a functional single ventricle.MethodsBetween January 1991 and December 2004, we identified six patients with Down’s syndrome among 263 who had undergone bidirectional superior cavopulmonary shunts (BCPSs). There were four males and two females. The age at BCPS ranged from 1 to 12 years (mean 4.3 ± 3.9 years), and body weight varied between 8.2 and 29.4 kg (mean 13.8 ± 7.8 kg). All six patients had an unbalanced complete atrioventricular septal defect, with right ventricular hypoplasia present in five and left ventricular hypoplasia in one.ResultsThere were no operative deaths, but one case required takedown of the BCPS. Except for this case, postoperative courses were generally uneventful. The median duration of follow-up was 46 months (range 12–80 months). Only two of five survivors after BCPS underwent a subsequent Fontan procedure, and one of these patients died of pulmonary hypertension post-operatively. The remaining three patients appeared to have significant risk factors for the Fontan procedure due to severe common atrioventricular valve regurgitation or persistent pulmonary vascular obstructive disease, including one who has completely dropped out from the Fontan track.ConclusionDown’s syndrome is a risk factor in patients with functionally single ventricle due to persistent pulmonary hypertension and airway obstruction. These results show that single ventricle repair in patients with Down’s syndrome is accompanied with difficulties, and patient selection for the Fontan procedure should be done carefully.

Bilateral pulmonary artery banding for hypoplastic left heart syndrome and related anomalies

ObjectiveBilateral pulmonary artery banding is considered an option for initial palliation in high-risk patients with hypoplastic left heart syndrome or related anomalies. However, there are potential interim morbidities, including ductal constriction, compromised growth of the ascending aorta, and pulmonary artery stenosis at the banding site. In addition, there are still controversies regarding the optimal timing and choice of the second-stage operation.MethodsBetween February 2003 and October 2005, twelve high-risk patients with hypoplastic left heart syndrome or related anomalies underwent bilateral pulmonary artery banding. An atrial septal defect was created simultaneously when the septum was intact or the defect was restrictive. After the procedure, intravenous prostaglandin E1 was continuously administered.ResultsThe median weight was 3.0 kg (range 1.8–3.6 kg), and the median age was 16 days (range 0–27 days). Atrial septum defect creation was performed simultaneously in two patients. Ten of the twelve patients were discharged from the hospital. One patient died of progressive multiple organ failure and another patient died of cerebral hemorrhage. Eight patients developed various degrees of ductal constriction and required dose adjustment of prostaglandin E1. Two patients underwent ductal arteriosus stent placement: one was unsuccessful owing to the size mismatch between the stent and the ductus. The diameter of the ascending aorta remained unchanged until the time of the second-stage operation, except in two patients who had a sufficiently sized aorta at the time of pulmonary artery banding. Pulmonary arterial branch stenosis developed at the banding site in three patients. At the time of the second-stage operation, the Norwood procedure was performed in seven patients, biventricular repair in two, and Norwood plus Glenn procedure in one.ConclusionBilateral pulmonary artery banding is an option to salvage high-risk neonates with hypoplastic left heart syndrome or related anomalies. However, it is associated with high interstage morbidity, and patients may benefi t from early conversion to the Norwood operation.

Fate of Trileaflet Equine Pericardial Extracardiac Conduit Used for the Correction of Anomalies Having Pulmonic Ventricle–Pulmonary Arterial Discontinuity

BACKGROUND External conduits used for the repair of congenital heart diseases having discontinuity between the pulmonic ventricle and the pulmonary artery still carries a high risk of reoperation. Between June 1983 and June 1992, handmade equine pericardial conduit with fabricated trileaflet valve had been the conduit of choice in our institute. The aim of this study is to clarify the temporal sequence of conduit obstruction in this material and to formulate the optimal surgical strategies for this disease entity. METHODS One hundred forty-three patients have undergone extracardiac conduit repair using this conduit. Postoperative catheterization performed within 2 months showed pulmonary to systemic ventricular systolic pressure ratio of 0.57 +/- 0.17 with the pressure gradient between pulmonic ventricle and pulmonary artery of 21.1 +/- 17.2 mm Hg. In 63 patients among the survivors, a series of Doppler two-dimensional echocardiographic images could be clearly obtained. RESULTS Moderate-to-severe degree of pulmonary insufficiency represented only 3.2% of all cases within 3 months, which rapidly increased to 14.3% at 1 to 3 years and 32.8% at 3 to 5 years. However, the rate of increase of pulmonary insufficiency diminished beyond 5 years with 34.9% at 5 to 7 years and 40.0% at 7 to 9 years. Estimated pressure gradient calculated by Bernoullis equation applied in the same patient subset was 4.1 +/- 7.9 mm Hg within 3 months, which progressively increased to 7.1 +/- 11.8 mm Hg at 1 to 3 years, 21.0 +/- 24.0 mm Hg at 3 to 5 years, 40.2 +/- 25.9 mm Hg at 5 to 7 years, and 71.3 +/- 34.0 mm Hg at 7 to 9 years. Among patients with a pressure gradient across the conduit of more than 40 mm Hg at follow-up catheterization, the primary cause of the obstruction was attributed to degeneration of the valve in 7 patients, whereas sternal compression was strongly suspected as the primary cause in the other 8 patients. Intimal peel was not obvious in the excised specimens. CONCLUSIONS Degeneration of the valve in the equine pericardial conduit became prominent at 3 to 5 years after the operation, whereas the pressure gradient across the conduit continued to progress thereafter. A thick and hardened valve from degeneration and varying degrees of external compression by the sternum were delineated at the site of stenosis.

Tetralogy of Fallot With Subarterial Ventricular Septal Defect

BACKGROUND Tetralogy of Fallot with subarterial ventricular septal defect is frequently seen among Asians. Compared with infracristal ventricular septal defect, postoperative right ventricular outflow obstruction is more likely because of subpulmonary extension of the defect. Moreover the incidence of aortic regurgitation is a concern because of the absence of a supporting infundibulum. METHODS Four hundred cases of classic tetralogy were reviewed, 61 of which had subarterial ventricular septal defect. RESULTS Aortic regurgitation (of more than mild degree) was identified in 7 cases with subarterial and 7 with infracristal ventricular septal defects. The mechanism of infracristal defect was predominantly an annular dilation before surgery. In contrast 5 cases with subarterial defect had progression of aortic regurgitation after operation yielding an actuarial incidence of 29.7% at 20 years. In 2 patients the cause seemed to be fixation or plication of the aortic valve annulus by the ventricular septal patch. Compared with infracristal defect, subarterial defect was associated with increased incidence of reoperation (12.0% versus 1.9% at 10 years, p = 0.01), frequent use of transannular patch (70.5% versus 45.7%, p = 0.0004), and worse New York Heart Association (NYHA) functional class (p = 0.007). Right ventricular outflow obstruction was the reason for reoperation in 3 patients with subarterial defect and was associated with worse NYHA classification in the long-term, on multivariate analysis (p = 0.0002). CONCLUSIONS Tetralogy with subarterial ventricular septal defect was associated with worse functional outcome. To prevent adverse outcomes, precise suturing of the distal ventricular septal patch, extensive infundibulectomy, lower threshold for transannular incision, and smaller-sized ventricular septal patch placement are warranted.

Autologous tissue-fragmented extracardiac conduit with rapid, stable endothelialization due to angiogenesis

OBJECTIVES Autologous angiogenic cytokines are known to activated by mincing stimulation, and well regulated in vivo. We applied this tissue fragmentation technique to a low-pressure pulmonary extracardiac conduit to obtain rapid endothelialization and stable neointima formation due to angiogenesis. METHODS Subcutaneous adipose tissue was obtained, minced, suspended, and sieved through highly porous fabric vascular prosthesis by pressurized injection. The adipose tissue fragmented graft with an autologous fresh pericardial monocusp valve was implanted between the right ventricle and the pulmonary artery in 13 dogs. The same grafts without fragments were implanted in 8 dogs as controls. No anticoagulation therapy was given. RESULTS Grafts were removed 6 to 1,128 days after implantation. In the developed grafts, angiogenesis occurred throughout the interstices of the graft wall from the adventitial side, and host cells proliferated and migrated. Endothelialization was completed throughout developed grafts at 2 weeks. The intima was still thin up to 1,128 days and free of degenerative changes. In control grafts, however, capillary infiltration was limited to perigraft tissue at 2 weeks and endothelialization was not completed by 3 months. Under the endothelial cell layer, laminal elastic fibers were formed through the developed graft wall by 4 months and still maintained at 1,128 days. CONCLUSIONS The results demonstrated that adipose tissue fragmented extracardiac conduits induce rapid endothelialization and maintained thin intima with laminal elastic fibers. Long-term durability is expected based on results from using this technique in a low-pressure pulmonary system in dogs.

Autologous Reconstruction of Pulmonary Trunk at Reoperation After Extracardiac Conduit Repair

Between 1991 and 1993, 5 patients underwent reoperation for critical stenosis of extracardiac conduit. Indication for extracardiac conduit repair was pulmonary truncal atresia in 3 patients and coronary anomaly including single left coronary artery and left anterior descending artery from right coronary artery in 2 patients. Age at reoperation ranged from 8 to 23 years (mean, 16.2 years). Preoperative systolic pressure ratio of right to left ventricles ranged from 0.83 to 1.05 (mean, 0.93), with the pressure gradient across the conduit ranging from 52 to 100 mm Hg (mean, 74.4 mm Hg). At reoperation, stenotic conduit was completely removed and central pulmonary artery was extensively mobilized. In 4 patients who had a relatively short distance (15 to 25 mm) between the pulmonary arterial stump and the right ventriculotomy incision, the distal pulmonary arterial stump was anastomosed directly to the cranial margin of the right ventriculotomy incision to serve as a floor mode of autologous tissue. In 1 patient with a long distance (40 mm), right ventricular-pulmonary arterial continuity was restored with a tailored autologous pericardial tube. There were no early or late deaths. Postoperative catheterization study revealed a satisfactory reduction of right ventricular pressure with the systolic pressure ratio ranging from 0.42 to 0.51 (mean, 0.47) and the pressure gradient across the right ventricular outflow tract ranged within 13 mm Hg (mean, 5 mm Hg). Restoration of right ventricular-pulmonary arterial continuity was successfully achieved by introducing the concept of autologous tissue repair even at reoperation instead of the insertion of new extracardiac conduit in patients with tetralogy of Fallot after extracardiac conduit repair.