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Biomedical subjects

C L Backer

Publications and source records attributed to C L Backer.

At least 73 records · Page 4Linked to original sources
PubMed1995

Repair of complete atrioventricular canal defects: results with the two-patch technique.

BACKGROUND: Between 1983 and 1994, 115 infants and children underwent repair of a complete atrioventricular canal defect with the two-patch technique and routine mitral valve "cleft" closure. METHODS: A retrospective review of these 115 patients was performed. Age at the time of repair ranged from 1 month to 108 months (mean age, 14.2 +/- 16.5 months; median age, 8 months). Preoperative cardiac catheterization in 113 patients revealed a mean pulmonary to systemic flow ratio of 3.37 +/- 1.8, a mean pulmonary artery systolic pressure of 71.1 +/- 15.7 mm Hg, and a mean pulmonary vascular resistance of 4.9 +/- 3.3 units. Associated anomalies included Down's syndrome (99 patients), patent ductus arteriosus (47), and coarctation of the aorta (4). Rastelli classification was A (76 patients), B (10), C (24), and unknown (5). Twenty-four patients had intraoperative epicardial or transesophageal echocardiography. RESULTS: Although there was a trend toward increasing mean preoperative pulmonary vascular resistance with age from 2.1 +/- 0.9 units (0 to 3 months) to 4.0 +/- 2.6 units (4 to 6 months) to 5.7 +/- 3.0 units (7 to 12 months), the mean pulmonary vascular resistance of each age group was not significantly different from that of the main group. The operative survival rate was 94% (seven early deaths) and the overall survival rate, 91% (three late deaths). Intraoperative echocardiography altered the surgical therapy for 1 patient. No patient has required reoperation for a residual ventricular septal defect. Four patients (3.5%) had heart block requiring permanent pacemakers. Eight patients (7%) required reoperation for mitral insufficiency; 6 of whom had successful repair of a residual cleft. CONCLUSIONS: For infants with complete atrioventricular canal defect, repair using the two-patch technique with routine mitral valve cleft closure at 4 to 6 months of age results in a low operative mortality, a low incidence of permanent heart block, and a low reoperation rate for mitral insufficiency.

Age Factors↗
PubMed1995

Inhaled nitric oxide for children with congenital heart disease and pulmonary hypertension.

BACKGROUND: Endothelium-derived nitric oxide (NO) is a potent vasodilator and a major mediator of pulmonary vascular tone. METHODS: Five infants underwent a trial of inhaled NO with hemodynamic monitoring in the operating room after atrioventricular canal repair. An additional 15 patients with congenital heart disease and refractory pulmonary hypertension were treated with inhaled NO for 1 day to 10 days postoperatively. RESULTS: In the 5 infants with atrioventricular canal, corrective surgical intervention and conventional therapy (hyperventilation, inspired oxygen fraction of 0.80, and inotropic agents) lowered mean pulmonary artery pressure from 49.5 +/- 10.5 to 20.0 +/- 2.2 mm Hg (p < 0.001). Adding inhaled NO further decreased mean pulmonary artery pressure to 18.0 +/- 2.8 mm Hg (p = not significant). Inhaled NO had no effect on ventricular function curves (inflow occlusion) in this group. In the 15 patients with refractory postoperative pulmonary hypertension, 11 had a favorable response to inhaled NO, with a decrease in mean pulmonary artery pressure from 30.9 +/- 5.8 to 23.1 +/- 5.4 mm Hg (p < 0.01) in 8 patients with pulmonary artery catheters. CONCLUSIONS: These studies demonstrate that inhaled NO has minimal beneficial effect on pulmonary artery pressure or cardiac output in infants after repair of atrioventricular canal. Inhaled NO is effective in decreasing PAP postoperatively in select patients with congenital heart disease and pulmonary hypertension refractory to conventional therapeutic modalities.

Administration, Inhalation↗
PubMed1995

An analysis of lidocaine block of sodium current in isolated human atrial and ventricular myocytes.

Lidocaine is a Na+ channel blocker that is highly effective for the treatment of ventricular tachyarrhythmias, but is largely ineffective against atrial arrhythmias. If is not known if this differential efficacy is the result of differences in lidocaine inhibition of atrial v ventricular Na+ channels. The purpose of the present study was to characterize lidocaine block of Na+ channels in human atrium and ventricle. We used the whole cell voltage clamp technique with low external and internal Na+ concentrations (5 mM) to study the Na+ current (INa) in single human atrial and ventricular cells isolated enzymatically from specimens obtained during surgery. We found that tonic block of peak INa by lidocaine (200 microM, holding potential = -140 mV, 0.1 Hz, at 17 degrees C) was not voltage dependent in either cell type. Reduction of maximal peak Na+ conductance in 41 atrial cells (19.8 +/- 2.7%) and nine ventricular cells (22.6 +/- 1.7%) was virtually identical. The rate of onset of block development was determined during depolarization to either -80 mV or -20 mV. The time course of onset of block was described by a single exponential at -80 mV and by a double exponential at -20 mV. When the rate of block onset during a single conditioning depolarization was compared to that which developed during conditioning by a train of brief pulses (3 ms, 30 Hz), onset was faster during the pulse train. The results were nearly identical for atrial and ventricular INa. The time constants of recovery from block following either single pulse or multiple-pulse conditioning did not differ. These data suggest that lidocaine binds to both the activated and inactivated states of the human cardiac Na+ channel. Using an analytical method based upon the Guarded Receptor Hypothesis, we calculated apparent rate constants describing lidocaine's interaction with the three primary states of the human Na+ channel (resting, activated and inactivated). Rate constants were similar to those reported for other mammalian species. Our results demonstrate that lidocaine block of INa is virtually identical for human atrial and ventricular cells; thus additional mechanisms must be invoked to explain the differential efficacy of lidocaine against ventricular as compared to atrial dysrhythmias.

Adolescent↗
PubMed1995

beta-Adrenergic modulation of the inwardly rectifying potassium channel in isolated human ventricular myocytes. Alteration in channel response to beta-adrenergic stimulation in failing human hearts.

The beta-adrenergic modulation of the inwardly-rectifying K+ channel (IK1) was examined in isolated human ventricular myocytes using patch-clamp techniques. Isoproterenol (ISO) reversibly depolarized the resting membrane potential and prolonged the action potential duration. Under the whole-cell C1- -free condition, ISO applied via the bath solution reversibly inhibited macroscopic IdK1. The reversal potential of the ISO-sensitive current was shifted by approximately 60 mV per 10-fold change in the external K+ concentration and was sensitive to Ba2+. The ISO-induced inhibition of IK1 was mimicked by forskolin and dibutyrl cAMP, and was prevented by including a cAMP-dependent protein kinase (PKA) inhibitor (PKI) in the pipette solution. In single-channel recordings from cell-attached patches, bath applied ISO could suppress IK1 channels by decreasing open state probability. Bath application of the purified catalytic sub-unit of PKA to inside-out patches also inhibited IK1 and the inhibition could be antagonized by alkaline phosphatase. When beta-adrenergic modulation of IK1 was compared between ventricular myocytes isolated from the failing and the nonfailing heart, channel response to ISO and PKA was significantly reduced in myocytes from the failing heart. Although ISO inhibited IK1 in a concentration-dependent fashion in both groups, a half-maximal concentration was greater in failing (0.12 microM) than in nonfailing hearts (0.023 microM). These results suggest that IK1 in human ventricular myocytes can be inhibited by a PKA-mediated phosphorylation and the modulation is significantly reduced in ventricular myocytes from the failing heart compared to the nonfailing heart.

Adrenergic beta-Agonists↗
PubMed1994

Role of endomyocardial biopsy in rejection surveillance after heart transplantation in neonates and children.

OBJECTIVES: The aim of this study was to retrospectively evaluate the sensitivity of noninvasive surveillance (physical examination, echocardiography) of rejection in accurately predicting histologically documented rejection episodes. Additionally, the usefulness of routine scheduled biopsy and its safety in pediatric patients was explored. BACKGROUND: Endomyocardial biopsy has been utilized as the standard for rejection surveillance after heart transplantation in adults, but its role in documenting clinically suspected rejection and in routine surveillance of pediatric patients has not been agreed upon. METHODS: Heart transplantation was performed in 14 neonates and 21 children. The immunosuppressive regimen consisted of cyclosporine, azathioprine and prednisone. All patients underwent routine noninvasive rejection surveillance that included clinical examination and echocardiography. In the neonates, biopsy was performed quarterly beginning 6 months after transplantation, after cessation of prednisone therapy. In the children, biopsy was performed 15 times in the 1st year. A minimum of five biopsy samples were interpreted using the Working Formulation for Heart Transplant Rejection. RESULTS: In the neonates, 37 biopsies were performed. Evidence of rejection was present in only three biopsy samples obtained during eight episodes (38%) of clinically suspected rejection. In 29 biopsies performed when rejection was not clinically suspected, each biopsy was free of cellular infiltrate. In the children, 291 biopsies were performed. Evidence of rejection was present in only seven biopsies (41%) from 17 episodes of clinically suspected rejection. Cellular rejection was discovered during routine rejection surveillance biopsies in asymptomatic patients in 23 (8.4%) of 274 biopsies. CONCLUSIONS: In neonates with clinically suspected rejection, endomyocardial biopsy identified which patients did not require rejection therapy. Endomyocardial biopsy surveillance did not detect any unsuspected cases of rejection. In children, noninvasive rejection surveillance was less reliable even in asymptomatic patients, suggesting that periodic endomyocardial biopsy should be utilized.

Biopsy↗
PubMed1994

Vascularized muscle flaps for life-threatening mediastinal wounds in children.

Vascularized muscle flaps have been shown to be highly effective in adults for complicated mediastinal and thoracic wounds. They result in infection control, wound coverage, and preservation of life. Minimal experience exists with the use of these techniques in children. We review our experience with vascularized muscle flaps between 1985 and 1993 in treating life-threatening mediastinal wounds in 8 children. The 8 patients ranged in age from 1 day to 10 years; mean age was 2 years. Two patients had mediastinitis; one had an exposed Gore-Tex graft, and the other had an exposed homograft conduit. One patient had a midline defect with exposed right ventricle immediately beneath the skin. One patient had tracheal dehiscence after repair of an acquired tracheoesophageal fistula from battery erosion. One patient with Marfan's syndrome had a pectus deformity and an unstable sternum after emergent reoperation for a false aortic aneurysm. Two neonates had their sternum left open with a temporary Silastic skin patch after orthotopic cardiac transplantation because of swelling of the donor heart. One transplant patient had wound dehiscence. Vascularized muscle flaps used to heal the mediastinal wounds in this group included pectoralis major (10), rectus abdominis (3), and cervical strap (1). One infant with asplenia and an exposed Gore-Tex graft that had a delayed vascularized muscle flap died of Candida sepsis. Seven of 8 patients (85%) healed their mediastinal wound. Prompt recognition of thoracic wound complications facilitates immediate surgical intervention to obtain primary closure with vascularized muscle flaps, which promotes rapid healing in these children.

Child↗
PubMed1994

Forty-six years of patient ductus arteriosus division at Children's Memorial Hospital of Chicago. Standards for comparison.

OBJECTIVE: The authors reviewed a large surgical experience (during five decades) with ligation and division of patent ductus arteriosus (PDA) in light of previously reported historical standards and present-day alternatives. SUMMARY BACKGROUND DATA: Ligation of PDA was first performed by Gross in 1938. Various surgical techniques used since then have included ligation and division, simple ligation, and hemaclip application. Recently introduced therapies include percutaneous transcatheter ductal closure devices (PTDC) and video-assisted thoracotomy (VAT). Percutaneous transcatheter ductal closure device protagonists cite surgical recurrence rates as high as 22% to justify continued application. METHODS: Between 1947 and 1993, 98.2% of 1108 patients (premature babies excluded) had interruption of PDA by ligation and division. Recent improvements have included muscle-sparing thoracotomy, minimal use of tube thoracostomy, and same-day surgery. RESULTS: Mortality was zero and morbidity (4.4%) has been low over time. Mean age at surgery has decreased from 5.9 +/- 3.3 years to 3.6 +/- 3.8 years (p < 0.001); patients requiring blood transfusion decreased from 34% to 4.6% (p < 0.001); and length of hospital stay (LOS) has decreased from 12.1 +/- 2.9 days to 3.8 +/- 2.1 days (p < 0.001). Length of stay for the last 27 patients was 2.8 +/- .8 days. Patient ductus arteriosus recurrence rate is zero with this technique. CONCLUSIONS: Recurrence rates for PTDC are high with as yet unknown consequences of large catheter vascular access, endocarditis, or left pulmonary artery stenosis. Video-assisted thoracotomy for PDA interruption has the potential for uncontrolled exsanguinating hemorrhage. Open thoracotomy for PDA ligation and division can be performed safely and without recurrence through a muscle-sparing incision with short LOS. All other therapeutic interventions must be compared to these standards.

Cardiac Surgical Procedures↗
PubMed1994

Alterations in muscarinic K+ channel response to acetylcholine and to G protein-mediated activation in atrial myocytes isolated from failing human hearts.

BACKGROUND: A variety of previous studies have demonstrated reduced diastolic potential and electrical activity in atrial specimens from patients with heart disease. Although K+ channels play a major role in determining resting membrane potential and repolarization of the action potential, little is known about the effects of preexisting heart disease on human atrial K+ channel activity. METHODS AND RESULTS: We characterized the inwardly rectifying K+ channel (IKI) and the muscarinic K+ channel [IK(ACh)] in atrial myocytes isolated from patients with heart failure (HF) and compared electrophysiological characteristics with those from donors (control) by the patch-clamp technique. Resting membrane potentials of isolated atrial myocytes from HF were more depolarized (-51.1 +/- 9.7 mV, mean +/- SD, n = 30 patients) than those from donors (-73.0 +/- 7.2 mV, n = 4 patients, P < .001). The action potential duration in HF was longer than that in donors. Although acetylcholine (ACh) shortened the action potential, reduced the overshoot, and hyperpolarized the atrial cell membrane in HF, these effects were attenuated compared with those observed in donors. The whole-cell membrane current slope conductance in HF was small, the reversal potential was more positive, and the sensitivity to ACh was less compared with donors. In single-channel recordings from cell-attached patches, IK1 channel conductance and gating characteristics were the same in HF and donor atria. When ACh was included in the pipette solution, IK(ACh) was activated in both groups. Single-channel slope conductance of IK(ACh) averaged 42 +/- 3 pS (n = 28) in HF and 44 +/- 2 pS (n = 4) in donors, and mean open lifetime was 1.3 +/- 0.3 milliseconds (n = 24) in HF and 1.5 +/- 0.4 milliseconds (n = 4) in donors. These values were virtually identical in the two groups (not significantly different, NS), although both single IK1 and IK(ACh) channel densities were less in HF. Channel open probability of IK(ACh) was also less in HF (4.0 +/- 1.2%, n = 24) than in donors (6.8 +/- 1.1%, n = 3, P < .01). The concentration of ACh at half-maximal activation was 0.11 mumol/L in HF and 0.03 mumol/L in donors. In excised inside-out patches, IK(ACh) from HF required higher concentrations of GTP and GTP gamma S to activate the channel compared with donors. These results suggest a reduced IK(ACh) channel sensitivity to M2 cholinergic receptor-linked G protein (Gi) in HF compared with donors. CONCLUSIONS: Atrial myocytes isolated from failing human hearts exhibited a lower resting membrane potential and reduced sensitivity to ACh compared with donor atria. Whole-cell and single-channel measurements suggest that these alterations are caused by reduced IK1 and IK(ACh) channel density and reduced IK(ACh) channel sensitivity to Gi-mediated channel activation in HF.

Acetylcholine↗
PubMed1994

Management of severe congenital tracheal stenosis.

We have managed 23 infants and children with severe tracheal stenosis due to congenital complete tracheal rings producing a long-segment stenosis of the trachea. Nineteen (83%) have survived this life-threatening cause of airway obstruction, 7 of whom also had pulmonary artery slings. Pericardial patch tracheoplasty facilitated by partial cardiopulmonary bypass is currently our preferred technique for surgical repair. Eighteen patients (78%) underwent operative intervention, 3 of whom (17%) have died since surgery. The mean follow-up is 4.5 years. Bronchoscopy is essential for preoperative diagnosis and accurate intraoperative incision of the trachea, and is critical for long-term postoperative airway management. The more distal lesions are associated with increased complications and a higher mortality rate.

Airway Obstruction↗
PubMed1994

Normal left ventricular muscle mass and mass/volume ratio after pediatric cardiac transplantation.

BACKGROUND: The adaptive growth of the transplanted heart within the growing child may contribute to long-term cardiac performance. The ability to achieve increased ventricular volume and appropriate muscle mass in the face of immunosuppression and cardiac denervation has not been studied. We previously reported normal left ventricular (LV) volume growth over a 3-year period after cardiac transplantation. This study was designed to assess changes in LV mass and mass/volume ratio and their relation to LV end-diastolic pressure (LVEDP) 1 to 4 years after cardiac transplantation. METHODS AND RESULTS: Cardiac transplantation was performed in 18 patients, age 7 days to 18 years (median, 3.7 years). The indications for cardiac transplantation were cardiomyopathy (8 patients), hypoplastic left heart syndrome (7 patients), and postoperative structural congenital heart disease with ventricular failure (3 patients). The mean follow-up was 48 months, with a range from 29 to 70 months. Serial annual catheterizations were performed after 1 year (16 patients), 2 years (18 patients), 3 years (15 patients), and 4 years (8 patients). Cardiac index (Fick), LVEDP (baseline and after 10-mL/kg saline infusion delivered over 5 minutes), and systemic vascular resistance (SVR) were measured. LV diastolic volume index (LVDVI), LV mass index, and mass/volume ratio were determined angiographically according to the method of Lange and Rackley. The data were analyzed by repeated-measures ANOVA. Least-squares means and group SEM were calculated. No change in cardiac index, SVR, or baseline LVEDP was noted. The LVEDP doubled after fluid challenge, suggesting a restrictive process. The LVDVI remained near 60 mL/m2. The LV mass/volume ratio remained one. CONCLUSIONS: Appropriate increases in muscle mass occurred after cardiac transplantation, preserving normal mass/volume ratios despite somatic growth deficits associated with immunosuppressive therapy and denervation of the donor heart.

Body Surface Area↗
PubMed1993

Failure of the Hemashield extension in right ventricle-to-pulmonary artery conduits.

Between 1989 and 1991, 17 children underwent 18 right ventricle-to-pulmonary artery conduit placement operations using a composite of an aortic or pulmonary valved homograft and a Hemashield extension to the ventricle. Hemashield is a collagen-coated knitted Dacron graft with excellent compliance and hemostatic properties. Diagnoses included tetralogy of Fallot with pulmonary atresia (7), truncus arteriosus (6), and complex transposition of the great arteries (4). Mean age at conduit placement was 4.9 +/- 4.2 years, and all patients survived. At a mean follow-up of 14 +/- 4 months, postoperative Doppler echocardiographic gradients between the ventricle and pulmonary artery ranged from less than 20 to 60 mm Hg. At cardiac catheterization 13 +/- 3 months postoperatively (6 patients), the systolic pressure gradient across the conduits ranged from 14 to 90 mm Hg (mean gradient, 59 +/- 29 mm Hg). Conduit obstruction, when present, was demonstrated angiographically to be in the Hemashield portion and led to early conduit replacement six times in 5 patients (33% of operations) within 10 to 18 months (mean time, 14 months) after insertion of the original conduit. Pathologic examination of the explanted conduits revealed the obstruction to be a thick neointimal peel that was impossible to separate from the Hemashield graft. Failure of the Hemashield as an extension for ventricle-to-pulmonary artery conduits secondary to accelerated neointimal formation has led us to abandon its use in clinical practice.

Adolescent↗
PubMed1993

Restrictive ventricular septal defect: how small is too small to close?

Historically, indications for ventricular septal defect closure have included congestive heart failure, pulmonary hypertension, aortic insufficiency with or without aortic valve prolapse, and prior bacterial endocarditis. However, controversy exists as to how the lifetime risk of an isolated, nonoperated restrictive ventricular septal defect compares with the risk of surgical closure in an asymptomatic child. Between 1980 and 1991, cardiac catheterization and elective ventricular septal defect closure (age > 1 year, pulmonary to systemic flow ratio < 2.0) were performed in 141 patients aged 1 to 23 years (mean age, 6.1 +/- 4.7 years). Mean systolic pulmonary artery pressure was 26.9 +/- 13.0 mm Hg, and mean pulmonary to systemic flow ratio was 1.6 +/- 0.3. Aortic valve prolapse was present in 63 patients (45%), aortic insufficiency was present in 25 (18%), and 5 (3.5%) had prior bacterial endocarditis. There were no early or late deaths or major morbidity. No patient required a ventriculotomy to accomplish ventricular septal defect closure. Mean postoperative intensive care unit stay was 1.3 +/- 0.9 days, and mean hospital stay was 5.5 +/- 1.9 days. There were no instances of permanent complete atrioventricular dissociation, reoperations for bleeding, postoperative wound infections, or reoperations for residual or recurrent ventricular septal defect. These improved results justify a reevaluation of historic indications for ventricular septal defect closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Giant popliteal false aneurysm in an 8-year-old child.

Aneurysms of the arterial system are rare in children. Aneurysms of the popliteal artery are extremely rare in the pediatric population; the majority of these occur after penetrating trauma. The authors report the presentation, evaluation, and successful surgical repair of a giant popliteal false aneurysm found in an 8-year-old girl presumably secondary to blunt trauma.

Aneurysm, False↗
PubMed1993

Sodium current in isolated human ventricular myocytes.

Although fast sodium current (INa) plays a major role in the generation and conduction of the cardiac impulse, the electrophysiological characteristics of INa in isolated human ventricular myocytes have not yet been fully described. We characterized the human ventricular INa of enzymatically isolated myocytes using whole cell voltage-clamp techniques. Sixty myocytes were isolated from ventricular specimens obtained from 22 patients undergoing open-heart surgery. A low temperature (17 degrees C) and Na+ concentration in the external solution (5 or 10 mM) allowed good voltage control and facilitated the measurement of INa. Cs+ was substituted for K+ in both internal and external solutions to block K+ currents, and F- was added to the internal solution to block Ca2+ current. INa was activated at a voltage threshold of approximately -70 mV, and maximal inward current was obtained at approximately -30 mV (holding potential = -140 mV). The voltage dependence of steady-state INa availability (h infinity) was sigmoidal with half inactivation occurring at -97.3 +/- 1.1 mV and a slope factor of 5.77 +/- 0.10 mV (n = 60). We did not detect any significant differences in these parameters in cells from patients with a variety of disease states, with or without congestive heart failure. The overlap in voltage dependence of h infinity and Na+ conductance suggested the presence of a Na+ "window" current. An inactivation time course was voltage dependent and was fitted best by the sum of two exponentials. The rate of recovery from inactivation also was voltage dependent and fitted by the sum of two exponentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Captopril reduces graft coronary artery disease in a rat heterotopic transplant model.

BACKGROUND: Transplant coronary artery disease (CAD) is characterized by severe myointimal proliferation causing vascular stenosis. Nontransplant vascular injury models have shown that angiotensin converting enzyme (ACE) inhibitors reduce myointimal proliferation and preserve lumen integrity. We examined the effect of the ACE inhibitor captopril on graft CAD in a Lewis to F344 rat heterotopic cardiac transplantation model. METHODS AND RESULTS: Twenty-five control rats (group 1) were observed without captopril administration after heterotopic cardiac transplantation, and the other 19 rats (group 2) were administered captopril (50 mg/kg per day in drinking water) after heart transplantation. Graft survival 3 months after transplantation was significantly (P < .02) higher in group 2 (18 of 19, 95%) than that in group 1 (16 of 25, 64%). Cellular rejection grades of the heart allografts were significantly higher in group 1 than those in group 2 both at 3 months (grades, 2.5 +/- 0.4 vs 1.3 +/- 0.7; P < .01) and 6 months (grades, 2.4 +/- 0.9 vs 0.8 +/- 0.5; P < .05) after transplantation. The grades of graft CAD (vascular rejection) were also significantly higher in group 1 than those in group 2 both at 3 months (grades, 2.3 +/- 0.7 vs 0.9 +/- 0.9; P < .05) and 6 months (grades, 3.0 +/- 0.9 vs 0.9 +/- 0.3; P < .01) after transplantation. The cardiac allographs in group 2 showed minimal intimal proliferation, intact elastic laminae, and reduced smooth muscle cell proliferation. CONCLUSIONS: These results suggest that the ACE inhibitor captopril may be effective in prevention of accelerated graft CAD.

Animals↗
PubMed1993

Biventricular repair of hypoplastic right ventricle assisted by pulsatile bidirectional cavopulmonary anastomosis.

The right ventricle in patients with severe outflow obstruction or atresia and a small tricuspid valve often remains too hypoplastic even after optimal palliation to tolerate biventricular repair with closure of the atrial septal defect. In these patients, nonpulsatile cavopulmonary (Glenn) anastomosis has traditionally facilitated biventricular repair. In 1989, Billingsley and associates reported the addition of a bidirectional cavopulmonary anastomosis to the definitive biventricular repair in patients with hypoplastic right ventricle, pulmonary atresia, and intact ventricular septum. The atrial septal defect was left open with an adjustable snare for later closure. We report five patients with hypoplastic right ventricle (mean diastolic volume 48.4%, mean stroke volume 40.2% of predicted value) who had the atrial septal defect closed at the time of the biventricular repair. Four patients, who had the bidirectional cavopulmonary anastomosis supplementing the biventricular repair, had no evidence of excessive right atrial or superior vena cava hypertension postoperatively. One patient, who had atypical tetralogy of Fallot with tricuspid stenosis, developed recurrent pericardial tamponade and marked hepatomegaly following conventional tetralogy repair with closure of the atrial septal defect. These complications were controlled with the addition of bidirectional cavopulmonary anastomosis 2 months later. Postoperative hemodynamic or Doppler studies in these patients revealed pulsatile flow in the entire pulmonary artery system, including the artery distal to the Glenn anastomosis. This modification of biventricular repair allows primary closure of the atrial septal defect and provides pulsatile arterial flow in the entire pulmonary artery, even when the right ventricle is significantly hypoplastic.

Adult↗