Transesophageal echocardiography detects thrombus formation not identified by transthoracic echocardiography after the Fontan operation.

Transesophageal echocardiography demonstrated six instances of venous thrombus formation in the inferior vena cava, right atrium and caval-pulmonary anastomosis region in four children after a modified Fontan operation. Transthoracic surface echocardiography failed to identify these thrombi in five of the six cases because of the posterior location of the thrombus or imaging interference from surgical hardware. These thrombotic episodes occurred 2 days to 5 years after the Fontan operation in children 25 to 168 months of age. Clinical features of compromised cardiac performance with cyanosis or inadequate perfusion were present during four of the six episodes. In two patients, thrombi occurred around transvenous permanent atrial pacing leads. Therapy to eliminate thrombus included surgery (two cases), anticoagulation with warfarin (three cases) and streptokinase thrombolysis (one case). Disappearance of the thrombus was confirmed by transesophageal study in three of the four cases with follow-up echocardiography. Transesophageal echocardiographic demonstration of atrial and pulmonary thrombi that could not be seen by transthoracic imaging suggests that these thrombi occur with greater frequency in patients who have undergone the Fontan operation than was previously suspected.

Right ventricular outflow reconstruction with cryopreserved homografts in pediatric patients: intermediate-term follow-up with serial echocardiographic assessment.

OBJECTIVES: This study was performed to assess by echocardiography the intermediate-term outcome of cryopreserved homografts employed in pulmonary outflow reconstruction in children and to validate the reliability of Doppler echocardiography in their evaluation. BACKGROUND: Cryopreserved homografts have become the most widely used pulmonary conduits. Previous reports have shown the occurrence of homograft regurgitation in the immediate postoperative period and the propensity of regurgitation to progress. Although Doppler echocardiography has been useful in assessing extracardiac valved conduit stenosis, its reliability in assessing a large series of cryopreserved homografts has not been documented. METHODS: Echocardiograms of 41 patients (43 homografts) who underwent operations between December 1986 and October 1992 were retrospectively reviewed. The median age of patients at operation was 37.5 months (range 3 to 333), and the median duration of follow-up was 28.5 months (range 1 to 68). Homograft regurgitation was classified on a scale of 0 to 4+. Pressure gradients across the homografts measured in 23 catheterizations were correlated with corresponding echocardiographic gradients. RESULTS: Regurgitation: Homograft regurgitation occurred in 100% of patients at follow-up. Progression of severity > 2 grades occurred during follow-up in 35% and was associated with operation before age 18 months (p < 0.002) and stenosis progression (p < 0.05) but not with homograft type (aortic or pulmonary). These data predict that 50% of patients operated on before 18 months of age will have severe regurgitation by 15 months postoperatively compared with only 15% operated on after 18 months. Stenosis: At follow-up, 51% of homografts had a stenotic gradient > or = 25 mm Hg predominantly at the distal anastomosis, and stenosis progression was related to young age at operation (< 18 months, p < 0.005) and small conduit size (p < 0.01). Fifty percent of conduits implanted before age 18 months could be predicted to stenose by 21.8 months compared with only 5% of those implanted after age 18 months. The gradient measured from Doppler echocardiography correlated well with the catheterization gradient (r = 0.86). CONCLUSIONS: Cryopreserved homograft dysfunction is frequent and progressive. Young age at operation (< 18 months) predicts more rapid deterioration. Doppler echocardiography is reliable in assessing the systolic gradients across homografts. Serial echocardiographic assessment in the follow-up of these patients accurately characterizes these problems.

Outcomes in critically ill neonates with pulmonary stenosis and intact ventricular septum: a multiinstitutional study. Congenital Heart Surgeons Society.

OBJECTIVE: This study attempted to determine the optimal therapeutic interventions by risk-adjusted comparisons of early and intermediate-term outcomes. BACKGROUND: The variety of interventions and the small case load at individual institutions have delayed the generation of reliable information concerning therapy for this condition. METHODS: In this prospective 27-institution study, 101 neonates were consecutively enrolled (between January 1, 1987 and January 1, 1991). Treatment was determined by the physicians. Demographic and morphologic details were tabulated. Dimensions of the pulmonary "anulus" and tricuspid anulus were measured on echocardiograms, and right ventricular cavity size was estimated. Right ventricular-pulmonary trunk pressure gradients were tabulated. Numerous analyses were made. RESULTS: Severe pulmonary valve stenosis and an intact ventricular septum were present in all patients. The right ventricular-pulmonary trunk junction ("anulus") was severely narrowed in 15%. Right ventricular cavity size was severely reduced in 4%. The tricuspid valve was small in 15% of patients; its diameter was poorly correlated with right ventricular cavity size. Eighty-nine percent and 81% of patients survived > or = 1 month and 4 years, respectively, after the initial procedure. Multivariable analysis identified no patient-specific risk factors for death. Only open pulmonary valvotomy without a support technique was uniformly a procedural risk factor; under some circumstances, transannular patching without a shunt was a risk factor. The right ventricular-pulmonary trunk gradient immediately after valvotomy was < 30 mm Hg in 81% of patients and was similar after surgical and balloon valvotomy. In 74% of patients, no intervention was required after the first accomplished intervention. CONCLUSIONS: Marked variation in morphology is uncommon in critical pulmonary stenosis in neonates. Percutaneous balloon valvotomy and certain types of surgical valvotomy are optimal initial procedures. The unusual situation of a small pulmonary "anulus" may initially require a transannular patch and a systemic-pulmonary artery shunt.

Management of atrial flutter after the Fontan procedure.

OBJECTIVES: The purpose of this study was to review the management of atrial flutter occurring after the Fontan procedure. BACKGROUND: Atrial flutter occurs frequently after the Fontan procedure and is often hemodynamically poorly tolerated. METHODS: The patients' charts were reviewed for relevant information. RESULTS: Between 1984 and 1992, 18 patients had atrial flutter after the Fontan procedure. The underlying heart defect was tricuspid atresia in nine, mitral atresia in six and double inlet left ventricle in three. All but three patients had undergone previous palliative surgery. The time interval from Fontan operation to atrial flutter was < 1 day to 16 years (mean 3.7 years). Seven had early atrial flutter before leaving the hospital. Electrophysiologic study in 15 showed sinus node dysfunction in 12. Atrial flutter was inducible in all patients, and 13 had > 1 flutter configuration. Digoxin and a variety of other antiarrhythmic agents (mean 2.7 drugs/patient) were tried with poor results. Only digoxin, amiodarone, flecainide and propafenone showed some benefit when used alone or in combination. Antitachycardia pacemakers were implanted in 16 patients (endocardial 14, epicardial 2) and, with drugs, were useful in 8 (50%). Because atrial flutter was resistant to treatment, right atriectomy was performed in three patients (with benefit in two, one death), successful radiofrequency catheter His bundle ablation in one patient and catheter ablation of atrial flutter in three patients (two failed, one partial success). One patient underwent heart transplantation, and two died suddenly. Another died of complications after an elective epicardial pacemaker replacement procedure. CONCLUSIONS: Atrial flutter after the Fontan procedure is difficult to control. Aggressive drug and antitachycardia pacemaker therapy help about half of the patients. When these measures fail, other options, such as atriectomy, His bundle ablation or catheter ablation of atrial flutter, need consideration. The risk of sudden death justifies the use of such aggressive treatment methods.

Pulmonary/systemic flow ratio in children after cavopulmonary anastomosis.

OBJECTIVES: This study attempted to provide a formula for calculation of the pulmonary/systemic flow ratio in children after bidirectional cavopulmonary anastomosis. BACKGROUND: With the bidirectional cavopulmonary anastomosis, only the superior vena cava blood is oxygenated by the lungs. The inferior vena cava flow recirculates into the systemic circulation. The ratio of these flows will determine systemic arterial saturation. METHODS: According to the Fick principle, 1) Systemic cardiac output (liters/min) = Pulmonary venous flow + Inferior vena cava flow; 2) Systemic blood oxygen transport (ml/min) = Pulmonary venous blood oxygen transport + Inferior vena cava blood oxygen transport. By substituting the first equation into the second, Pulmonary/systemic flow ratio = (Systemic saturation - Inferior vena cava saturation)/(Pulmonary venous saturation - Inferior vena cava saturation). RESULTS: We applied the third formula to data obtained from 34 catheterizations in 29 patients after bidirectional cavopulmonary anastomosis. Mean [+/- SD] age at operation was 1.70 +/- 1.43 years, and mean age at catheterization was 2.95 +/- 1.65 years. The pulmonary/systemic flow ratio calculated for all 29 patients was 0.58 +/- 0.09. Of 17 patients with aortography, 10 had systemic to pulmonary collateral vessels. Patients with collateral vessels had a significantly higher pulmonary/systemic flow ratio (0.61 +/- 0.07 vs. 0.53 +/- 0.07, respectively, p < 0.02) and systemic saturation (88 +/- 4% vs. 82 +/- 4%, respectively, p < 0.002) than those without collateral vessels. The pulmonary/systemic flow ratio in those patients with no collateral vessels was similar to the previously reported echocardiographically derived superior vena cava/systemic flow ratio in normal children. CONCLUSIONS: The pulmonary/systemic flow ratio after bidirectional cavopulmonary anastomosis can be calculated. Pulmonary blood flow in these patients determines systemic saturation and accounts for the majority of venous return in young children.

Stress testing for comparison of synthetic patch aortoplasty with resection and end to end anastomosis for repair of coarctation in childhood.

Excellent clinical results have been achieved by both resection with end to end anastomosis and synthetic patch aortoplasty for the repair of coarctation of the aorta in older children. Increasing experience with exercise stress testing in the postoperative evaluation of patients with coarctation has allowed the discovery of less obvious differences between the two procedures. To evaluate these differences further, the stress tests of 50 postoperative patients who underwent coarctation repair were reviewed: 26 patients with end to end anastomosis and 24 with synthetic patch aortoplasty. Twenty normal control subjects were similarly exercised. Systolic blood pressure in the arm and leg was evaluated before and after the test. Heart rate, electrocardiogram and arm blood pressure were monitored during the test. The mean arm systolic blood pressure was higher at all points of measurement in the patients who underwent repair by end to end anastomosis than in the group who underwent patch aortoplasty. These systolic pressure differences reached statistical significance only for standing arm blood pressure before exercise (p less than 0.05) and for supine arm systolic blood pressure immediately after exercise (p less than 0.01). There was no difference in arm-leg pressure gradient between the two study groups before exercise; however, after exercise the group with end to end anastomosis had significantly higher arm-leg pressure gradients (p less than 0.001). Significant differences between the two types of repair not apparent at rest were found immediately after exercise. The long-term prognostic importance of an exercise-induced arm-leg blood pressure gradient remains to be determined. However, exercise stress testing is sensitive in demonstrating these differences.

Hemophilus influenzae b pericarditis in children.

Recent experience in the diagnosis and management of Hemophilus influenzae b pericarditis is described in five children. Anterior pericardectomy appears to be the preferred method of surgical drainage because it was associated with a shorter hospitalization than pericardiocentesis or closed or open pericardotomy and removed the risk of recurrent cardiac tamponade and constrictive pericarditis. Countercurrent immunoelectrophoresis of sera and pericardial fluid was used to rapidly identify the etiology of pericarditis in four of four patients tested. The observation that three children appeared to develop pericarditis in the absence of a contiguous infectious focus suggests that bacteremic seeding of the pericardium may be important in the pathogenesis of this disease.

Structural changes in a porcine xenograft after implantation for 105 months.

Morphologic studies including light microscopy and transmission and scanning electron microscopy were performed on a formaldehyde-fixed porcine xenograft prosthesis that functioned well for 8 years and had been implanted for 105 months in the tricuspid valve position. It is the oldest implanted valve studied in this manner. Although all leaflets had some gross deterioration, only one had adherent thrombus. The degenerative changes in the connective tissue from all leaflets were similar to those recently reported in glutaraldehyde-fixed porcine valves implanted for shorter periods. The surfaces of the two nonthrombosed leaflets and small portions of the surface of the thrombosed leaflet were endothelized, and the endothelium appeared to have little or no effect on the degenerative changes in the subjacent connective tissue. Further, the endothelium did not extend over the examined portion of the synthetic anulus of the prosthesis, suggesting that its origin was possibly from cells circulating in the blood.

Pleuroperitoneal shunt for persistent pleural drainage after Fontan procedure.

Persistent effusions of chylous fluid may prolong the hospitalization period of many patients who have had a Fontan procedure. Herein we report the case histories of two patients in whom use of a pleuroperitoneal shunt to control the effusion shortened the hospital stay by several weeks.

Spinal cord injury associated with hyperthermia during aortic coarctation repair.

Three infants with coarctation of the thoracic aorta, patent ductus arteriosus (PDA), and ventricular septal defect (VSD) underwent repair of the coarctation in three different institutions. Despite a technically uncomplicated operation, each was noted to have significant paraplegia postoperatively. Retrospective analysis revealed that each patient had been hyperthermic during the time of aortic cross-clamping. It is possible that the hyperthermia, either alone or in combination with other factors, contributed to the development of paraplegia in these three infants.

Augmentation of pulmonary blood flow after right ventricular bypass.

We have studied pulmonary hemodynamics after right ventricular bypass in dogs. Manipulations of pulmonary vascular resistance and transpulmonary blood pressure difference (delta Pp) made it possible to increase pulmonary blood flow. Decreasing resistance by raising arterial pH from 7.25 to 7.38 increased flow by 24.9%. Infusion of homologous blood to increase right atrial pressure from 10 to 30 mm Hg lowered resistance 41.5% and raised flow 183%. Left ventricular bypass (left atrium to aorta) lowered left atrial pressure, increased arteriovenous pressure gradient by 41.4%, and raised flow 32.8%. These experiments support earlier clinical observations of the importance of low pulmonary vascular resistance and of good left ventricular function both in selection of patients and in postoperative management after right ventricular bypass. Attention to the principles we discuss may permit right ventricular bypass operation in some patients who would not be operable by current criteria.

Coronary sinus septal defect. Surgical considerations.

The coronary sinus septal defect is an uncommon anomaly. If it is not suspected, found, and repaired at operation, a residual intracardiac shunt will result. The defect usually is associated with a left superior vena cava (LSVC), which necessitates special consideration in the conduct of cardiopulmonary bypass. Our recent treatment of three cases of coronary sinus septal defect stimulated us to review the embryology, anatomy, diagnosis, and surgical treatment of this malformation.

Abnormalities of regional lung function associated with ventricular septal defect and pulmonary artery band.

Xenon-133 ventilation-perfusion scans and technetium-99m angiocardiograms were performed 47 times in 34 patients. All patients had ventricular septal defect (VSD), 17 with pulmonary artery band (PAB), 6 with isolated VSD, 4 with pulmonary valvar stenosis (PS), and 7 with transposition of the great arteries (d-TGA), VSD, and PAB. Patients with VSD had slightly depressed ventilation fraction of the left lung and slightly elevated perfusion fraction of the left lung, both before and after closure of the VSD. Patients with VSD and PAB had slightly depressed ventilation fraction of the left lung but perfusion fraction of the left lung that was either markedly elevated or markedly depressed. After closure of VSD and removal of PAB the perfusion abnormality returned toward normal in some patients but remained abnormal in most. The findings were similar in most patients with d-TGA. Ventilation-perfusion ratio was nearly normal in patients with VSD alone, both before and after closure of VSD. In patients with VSD with PAB the severe abnormality of ventilation-perfusion ratio returned toward normal after corrective operation but did not reach normal. There was no abnormality of distribution of perfusion along the cephalocaudal axis of the lung with the patient supine.

Tetralogy of Fallot with discrete fibrous subaortic stenosis.

This is the first reported case of discrete fibrous subaortic stenosis in tetralogy of Fallot. Transaortic excision of the subaortic membrane was readily accomplished. To detect this and other forms of left ventricular outflow-tract obstruction in tetralogy of Fallot before surgery, routine selective left ventriculography is advocated.

Pulmonary artery sling.

Pulmonary artery sling is an uncommon and potentially lethal vascular anomaly that can produce airway obstruction. Despite the availability of a corrective operation, the mortality rate remains very high (50 per cent of surgically treated children) due to the high incidence of associated obstructive anormaliies of the tracheobronchial tree. The survivors of corrective operation have done well symptomatically. However, when restudied, most have been found to have no pulmonary blood flow to the left lung. Successful treatment requires early recognition of the anomaly, adequate preoperative investigation for associated anormalies (especially those of the tracheobronchial tree), a technically perfect vascular reconstruction, and meticulous postoperative respiratory therapy.

Atrial wound healing with polyglycolic acid and polypropylene sutures.

The suitability of absorbable suture for atrial repair was tested in 25 rabbits in which atrial wounds were repaired with either polyglycolic acid or polypropylene suture. Tensile strength and wound thickness were measured at several time intervals up to 8 weeks after wounding. With each animal used as its own control, the ratio of wound tensile strength to that of unwounded atrium and of wound thickness to thickness of unwounded atrium were compared at several time intervals. There was no difference between polyglycolic acid and polypropylene suture lines in tensile strength index, but the wall thickness index was significantly lower for polyglycolic acid sutures. The latter finding was probably due to a less intense chronic inflammatory response in the polyglycolic acid group. Because of the necessity for maximal size and future growth of atrial anastomoses after repair of some congenital cardiac malformations, polyglycolic acid suture appears to be a reasonable alternative to nonabsorbable suture for atrial repair in children.

Pericardial injury by antibacterial irrigants.

We injected antibacterial solutions into rabbit pericardium to investigate tissue injury. Povidone-iodine was the only irrigant found to cause substantial damage. These data lend experimental support to recent clinical observations that suggest a causal relation between pericardial irrigation with povidone-iodine and the later development of constrictive pericarditis.

Hydroxyethyl starch in priming fluid for cardiopulmonary bypass.

The physiochemical characteristics of hydroxyethyl starch make it suitable for use as a colloidal blood plasma substitute. In high doses, this drug may interfere with blood coagulation. Because of its effectiveness and low cost, we have used hydroxyethyl starch rather than albumin in the priming fluid for cardiopulmonary bypass: 500 ml of 6% hydroxyethyl starch and 2,000 ml of lactated Ringer's solution. To determine if excessive bleeding has been associated with the use of hydroxyethyl starch, we reviewed 760 cardiac operations. The patients were 49.9 +/- 0.5 years old (mean +/- SEM) and weighed 73 +/- 1 kg. Blood loss during the first postoperative day was 578 +/- 25 ml, and 4.0 +/- 0.2 units of bank blood were utilized in the perioperative period. We have used an improved method of administering heparin and protamine for the past 3 years. In the 461 patients operated upon since then, blood loss was 437 +/- 21 ml, 2.9 +/- 0.1 units of bank blood were used, and excessive postoperative bleeding necessitated re-exploration in nine patients (2.0%). These results compare favorably with other recently published series in which hydroxyethyl starch was not used in the pump prime. Thus the dose of hydroxyethyl starch in our priming fluid does not appear to be associated with excessive bleeding. In view of its safety and low cost, hydroxyethyl starch is a suitable colloidal blood plasma substitute for use during cardiopulmonary bypass.

Results of decortication in chronic empyema with special reference of paragonimiasis.

During a recent 6 years period, we managed chronic empyema by decortication, either alone or in combination with thoracoplasty, in 58 patients: In 16 patients, the empyema was a complication of Paragonimus westermani infestation (PWI), in 20, tuberculosis (TB), and in 22, of varied origins. There were no operative deaths, and satisfactory or good results were obtained in 55 patients (94.8%). We believe that the result in a patient in whom thoracoplasty is required should be called satisfactory, not good. Only 55% of the TB group achieved a good result, compared with 89% of the other patients. Of the 10 patients who required a thoracoplasty, seven were in the TB group. Empyema complicating TB is associated with a higher incidence of fistula formation and is more difficult to treat than other empyemas. The empyema associated with PWI develops more slowly, tends to form fewer fistulas, and eventuates in a good result more often than empyema associated with TB. Two of our three poor results stemmed from failure to do a thoracoplasty when the lung did not expand. We recommend thoracoplasty when the lung does not expand well at operation; it should be done at the time of decortication to avoid the necessity for a second major procedure. Chronic empyema is a common complication of paragonimiasis in Korea and by inference in other parts of the world where PWI is endemic. As international travel increases, some patients with PWI and complicating empyema may be seen in the United States. American thoracic surgeons should be aware of this disease, its treatment and its chest complications.

Orthoterminally corrective operation in the presence of severe hypoplasia of a pulmonary artery.

Hypoplasia of the pulmonary arteries has been cited as a contraindication to right vertricular bypass operations. We have successfully corrected a lesion in which the left pulmonary artery was severely hypoplastic and have documented a good hemodynamic result postoperatively. Size of pulmonary arteries is less important than pulmonary vascular resistance as a criterion for orthoterminal correction.