Michael R. Nihill

Status of the adult and adolescent after repair of tetralogy of Fallot.

Because increasing numbers of patients with surgically repaired tetralogy of Fallot (TOF) are surviving to adulthood, this study was done to provide follow-up data for physicians concerned with their care. We reviewed the current status of 233 patients born before January 1962 who had repair ofTOF at a median age of 9.7 years (range 11 months to 36 years). There were 26 surgical deaths (11.1%), 12 late cardiacrelated deaths (5.9%) and three noncardiac deaths (1.3%). Eight of the 12 late deaths occurred suddenly and unexpectedly. In each of these eight patients we had previously documented elevated right ventricular systolic pressure as well as ventricular premature depolarizations (VPDs). Among the 95 patients who responded to a questionnaire, 84 denied symptoms, 28 were married, 44 had attended college and all were employed. Cardiac catheterization revealed an unsatisfactory hemodynamic result in 39 of 120 patients, 30 of whom were asymptomatic. The poor result was due to a large left-to-right ventricular shunt in eight patients, persistent right ventricular outflow obstruction in 25 patients, pulmonary vascular obstructive disease in five patients, and left ventricular cardiomyopathy in one patient. Among the 21 patients with VPDs, 17 underwent cardiac catheterization: 15 had a right ventricular systolic pressure > 60 mm Hg and all had elevated right ventricular end-diastolic pressure. We conclude that 1) clinical assessment alone is nonpredictive of the hemodynamic result and thus cardiac catheterization is indicated in all patients; 2) the combination of persistent elevation of right ventricular systolic pressure above 60 mm Hg and VPDs placed the patient at risk for sudden death; and 3) over 80% of adults with repaired TOF can lead a normal life without impairment of intellect, exercise tolerance or fertility.

Intravascular Stents in Congenital Heart Disease: Short- and Long-Term Results From a Large Single-Center Experience☆☆☆

OBJECTIVES This report describes the results of the Food and Drug Administrations phase 1 and 2 clinical trials of intravascular stents at Texas Childrens Hospital. BACKGROUND Since the late 1980s, intravascular stent implantation for the treatment of arterial and venous stenoses in congenital heart disease has been highly successful. METHODS Stents were placed in postoperative pulmonary artery (PA) stenoses, congenital PA stenoses or stenoses of systemic veins/venous anastomoses. Prospective collection of data according to protocol was done before intervention, after stent implantation and at follow-up catheterization. RESULTS At stent implantation, pressure gradients decreased significantly in all three groups (mean +/- SD): from 46 +/- 25 to 10 +/- 13 mm Hg in postoperative PA stenoses (p < 0.001); from 71 +/- 45 to 15 +/- 21 mm Hg in congenital PA stenoses (p < 0.001); and from 7 +/- 6 to 1 +/- 2 mm Hg in stenoses of systemic veins/venous anastomoses stenoses (p < 0.001). Vessel diameters markedly increased: from 6 +/- 3 to 12 +/- 3 mm in postoperative PA stenoses (p < 0.001); from 3 + 1 to 9 + 1 mm in congenital PA stenoses (p < 0.001); and from 3 +/- 4 to 12 +/- 4 mm in stenoses of systemic veins/venous anastomoses (p < 0.001). In the postoperative and congenital PA stenoses groups, right ventricular pressure decreased (right ventricular pressure indexed to femoral artery pressure ratio): from 0.63 +/- 0.2 to 0.41 +/- 0.02 (p < 0.001) and from 0.71 +/- 0.3 to 0.55 +/- 0.35 (p = 0.04), respectively. Perfusion to a single affected lung increased from 31 +/- 17% to 46 +/- 14% (p < 0.001). On recatheterization (mean 14 months), results varied minimally. Repeat angioplasty of residual stent stenoses was safe and effective. Complications included four early patients with stent migration, three with stent thrombosis and two deaths. There were no late complications. Significant restenosis occurred in only three patients. CONCLUSIONS Intravascular stents for the treatment of vascular stenoses in congenital heart disease provide excellent immediate and long-term results.

Outcome of 121 Patients with Congenitally Corrected Transpositionof the Great Arteries

Congenitally corrected transposition of the great arteries (ccTGA) is a rare disorder with reduced survival that is influenced by the presence of associated anomalies, tricuspid regurgitation (TR), and right ventricular (RV) function. The double switch procedure has been proposed as an aggressive surgical approach in selected patients. We sought to review our experience with conventional repair to determine if a change in surgical strategy was warranted. Clinical records of 121 patients with ccTGA and two adequate-sized ventricles were retrospectively reviewed. Median length of follow-up was 9.3 years; 5-, 10-, and 20-year survival rates were 92%, 91%, and 75%, respectively. Surgery was performed in 86 patients, including conventional biventricular repair in 47 patients. Risk factors for mortality by univariate analysis included age at biventricular repair (p = 0.04), complete atrioventricular (AV) canal defect (p = 0.02), dextrocardia (p = 0.05), moderate or severe TR (p = 0.05), and poor RV function (p = 0.001). By multivariate analysis, complete AV canal defect (p = 0.006) and poor RV function (p = 0.002) remained significant as risk factors for mortality. Risk factors for the development of significant TR included conventional biventricular repair (p = 0.03) and complete AV block (p = 0.04). Risk factors for progressive RV dysfunction included conventional biventricular repair (p = 0.02), complete AV block (p = 0.001), and moderate or severe TR (p < 0.001). This is the largest nonselected cohort of patients with ccTGA followed at a single center. Our results confirm that significant TR and poor RV function are risk factors for poor outcome and provide convincing evidence that patients undergoing conventional biventricular repair are at higher risk for deterioration of tricuspid valve and right ventricular function compared to palliated or unoperated patients. We support a move toward an alternative surgical approach (double switch procedure) in carefully selected patients.

Balloon dilation of unoperated coarctation of the aorta: short- and intermediate-term results.

Balloon dilation is effective in the immediate relief of obstruction due to unoperated coarctation of the aorta. However, the long-term benefits and complications of this procedure have not been established. Thirty-three patients underwent balloon dilation of unoperated coarctation using a percutaneous technique from November 1983 to December 1985. High quality biplane angiography was performed before and after dilation. Follow-up was obtained in 20 patients from 6 to 31 months following dilation. Angiography was performed at follow-up in 10, nuclear magnetic resonance (NMR) imaging in 10 and both NMR imaging and angiography in 3. Balloon dilation was successful in 31 of the 33 patients with a decrease in average systolic pressure gradient from 46 to 8 mm Hg. There was no significant change in gradient on follow-up physical examination and at recatheterization in 10 patients. In addition, there was no evidence of restenosis on follow-up angiography and NMR imaging. In two patients, a small aneurysm formed at the site of balloon dilation. Balloon dilation of unoperated coarctation is effective, providing lasting relief of coarctation gradient and no evidence of restenosis. However, because of the uncertain natural history of aneurysms after dilation, this procedure should be considered investigational until further follow-up on patients with and without an aneurysm is available.

Double balloon technique for dilation of valvular or vessel stenosis in congenital and acquired heart disease

Despite the generally excellent success with balloon dilation for the stenotic lesions of congenital and acquired heart disease, technical difficulties sometimes prevent satisfactory results. Such technical difficulties include: a large diameter of the anulus of the stenotic lesion relative to available balloon diameter, difficulty in the insertion or removal of the larger balloon catheters, and permanent damage to or obstruction of the femoral vessels by the redundant deflated balloon material of the large balloons. A double balloon technique was initiated to resolve these difficulties. With this method, percutaneous balloon angioplasty catheters were inserted in right and left femoral vessels, placed side by side across the stenotic lesion and inflated simultaneously. Dilation procedures using the two balloon technique were performed in 41 patients: 18 with pulmonary valve stenosis, 14 with aortic valve stenosis, 5 with mitral valve stenosis, 3 with vena caval obstruction following the Mustard or Senning procedure and 1 with tricuspid valve stenosis. Patient ages ranged from 1 to 75 years (mean 17.8) and patient weights ranged from 8.9 to 89 kg (mean 42.3). Balloon catheter sizes ranged from 10 to 20 mm in diameter. Average maximal pressure gradient in mm Hg before dilation was 61 in pulmonary stenosis, 68 in aortic stenosis, 21 in mitral stenosis, 12 in tricuspid stenosis and 25 in vena caval stenosis. Average maximal valvular pressure gradient after dilation was 13 in pulmonary stenosis, 24 in aortic stenosis, 4 in mitral stenosis, 0 in tricuspid stenosis, and 1 in vena caval stenosis. No major complications were encountered with the procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcatheter Patent Ductus Arteriosus Closure in an Infant Using the Gianturco-Grifka Vascular Occlusion Device

A 2-month-old child with Down syndrome and a large patent ductus arteriosus underwent transcatheter closure using a new Food and Drug Administration-approved occlusion device. This device is described, along with its usefulness for other vascular defects.

New Gianturco-Grifka Vascular Occlusion Device Initial Studies in a Canine Model

BACKGROUND Transcatheter closure of cardiovascular defects remains a challenge. Several occlusion devices are available, but each device has limitations. The purpose of this study was to evaluate the new Gianturco-Grifka vascular occlusion device (GGVOD) in a canine model. METHODS AND RESULTS A total of 26 GGVODs were implanted as part of short- and long-term studies. In the short-term study, 1 GGVOD was implanted in each of 11 systemic arteries from 3.2 to 9.0 mm in diameter. All 11 arteries were occluded immediately. In the long-term study, an aortopulmonary shunt was placed in 10 dogs (9, Gore-tex graft; 1, subclavian artery) followed by GGVOD implantation; additionally, a GGVOD was implanted in 5 subclavian arteries. The dogs were boarded for 3 to 6 months, then recatheterized and euthanatized. Immediately after implantation, the 5 subclavian arteries and 9 Gore-tex shunts were occluded completely; the 1 subclavian artery shunt had a small residual leak. At recatheterization, all 10 shunts and 5 subclavian arteries were occluded completely. Necropsy revealed all shunts to be occluded, with the aortic and pulmonic orifices covered with a neointimal layer. The mean fluoroscopic time needed for GGVOD implantation was 9 minutes (range, 3 to 22 minutes). CONCLUSIONS (1) In a canine model, the GGVOD is effective for transcatheter occlusion of arteries and aortopulmonary shunts from 3 to 9 mm in diameter. Possible indications in children include aortopulmonary collateral vessels, long patent ductus arteriosus, systemic-pulmonary shunts, AV malformations, and arteries supplying tumors. (2) GGVOD implantation requires a short fluoroscopic time.

Balloon expandable intravascular stents : aortic implantation and late further dilation in growing minipigs

Intravascular stents have been implanted in children with congenital and acquired vascular stenoses. Little information is known regarding the long-term results in growing patients, the implantation of multiple stents (in series), and the feasibility of further dilation. Nine stents were implanted in the abdominal aortas of 6 mini-pigs; in 3 pigs, 2 stents were implanted in series. Five pigs were recatheterized 196 +/- 17 days after stent implant. All stents were patent, with mild narrowing at the stent relative to the adjacent aorta; further stent dilation was performed. The stent diameter increased from 8.3 +/- 0.6 mm to 11.2 +/- 1.3 mm (p = 0.002), and the narrowing was relieved. These five pigs were catheterized 253 +/- 73 days after stent redilation. Each stent was patent without narrowing or pressure gradient. We conclude that intravascular stents do not interfere with normal growth, can be implanted in series, and can be further dilated.

The absent pulmonary valve syndrome. Considerations of management.

The absent pulmonary valve syndrome consists of a severely hypoplastic pulmonary valve with anular stenosis, aneurysmal dilatation of the main pulmonary artery with one or both pulmonary branches also dilated, and a ventricular septal defect. From 1955 to 1975, 15 patients were seen at Texas Childrens Hospital with this syndrome. Although anatomically similar to tetralogy of Fallot, the most significant symptoms during early infancy were secondary to bronchial compression resulting from the dilated pulmonary arteries and enlarged left atrium. Intracardiac repair performed on two infants at four months of age failed to ameliorate the respiratory symptoms and both died. Seven patients from 2.3 to 16 years of age were operated upon, with one late postoperative death. Five other patients have not yet received surgical intervention. We recommend vigorous continual respiratory therapy for infants and small children and intracardiac repair in older children since repair in infancy does not relieve respiratory symptoms. We do not recommend a prosthetic pulmonary valve unless there is persistently elevated main pulmonary artery pressure.

Refinements in the implantation of pulmonary arterial stents: impact on morbidity and mortality of the procedure over the last two decades.

INTRODUCTION There is limited data on medium to long-term outcome, and the morbidity and mortality associated with the implantation, of pulmonary arterial stents. PURPOSE To assess changes in morbidity and mortality over the last two decades. METHODS Retrospective analysis of all patients stented between September, 1989 and July, 2001. RESULTS We implanted 664 Palmaz stents in 338 patients. The overall number included 229 patients who had undergone repair of tetralogy of Fallot, in whom 468 stents were implanted, 61 patients with congenital stenosis of the branches of the pulmonary trunk, in whom we placed 115 stents, 16 patients after an arterial switch operation who had 38 stents, and 32 patients after the Fontan operation who had 43 stents implanted. The mean age was 12.2 years, and the mean weight was 38 kg. The mean systolic pressure gradient decreased from 41 to 8.7 mmHg, the mean diameter of the stented vessel increased from 5.4 to 11.2 mm, and the ratio of right ventricular to femoral arterial pressure decreased from 0.66 to 0.45, each of these being significant at the level of p being less than 0.01. At a mean follow-up of 5.6 years, the mean gradient was 20 mmHg, the mean ratio of pressure between right ventricle and femoral artery was 0.5, and mean luminal diameter was 9.3 mm. Complications included migration of the stent in 8 patients, and pulmonary edema, hemoptysis and death in 5 patients each. There has been no mortality or morbidity since July of 1997. Technical changes include conservative serial dilations in congenital pulmonary arterial stenosis, avoidance of over-dilation, and simultaneous implantation of stents in the right and left pulmonary arteries in those with systemic pulmonary arterial pressure. Technological advances included shorter stents, improved balloon profiles, and central inflation of the stents. CONCLUSIONS Modification of stenting practices, and increased experience of the operators over the last two decades, has virtually abolished any morbidity or mortality associated with the implantation of stents for congenital or postoperative pulmonary arterial stenoses.