PubMed Health⌕ Search

Biomedical subjects

R A Jonas

Publications and source records attributed to R A Jonas.

At least 145 records · Page 8Linked to original sources
PubMed1993

Review of current research at Boston Children's Hospital.

Both clinical and laboratory studies are being undertaken to investigate the deleterious neurologic and developmental effects associated with cardiopulmonary bypass, hypothermia, and circulatory arrest in the neonate and infant. A prospective, randomized clinical study of 171 neonates and young infants compared circulatory arrest with low-flow bypass (50 mL.kg-1.min-1). Circulatory arrest was associated with a higher incidence of early postoperative seizures as well as greater release of creatine kinase-BB. There was a strong correlation between duration of circulatory arrest and seizures (p = 0.004). The late consequences of these findings will be known at the completion of developmental assessment of all patients at 1 and 4 years of age. Laboratory studies have used a miniature piglet model that closely replicates clinical circulatory arrest. High-energy phosphate stores determined by magnetic resonance spectroscopy were maintained in animals undergoing 1 hour of low-flow bypass but became undetectable after 32 minutes of a 1-hour period of circulatory arrest. However, they returned to baseline within 3 hours of reperfusion as did cerebral blood flow and metabolism determined by microsphere studies. Piglets undergoing 1 hour of circulatory arrest showed more rapid recovery of cerebral adenosine triphosphate content and intracellular pH when managed with the pH-stat strategy during hypothermic bypass than with the more alkaline alpha-stat strategy. Other laboratory studies have examined pharmacologic methods of reducing cerebral injury associated with circulatory arrest including aprotinin, anti-CD18, neuronal receptor antagonists (MK801, NBQX), and blockade of glutamate release with adenosine in a cerebroplegia solution. These studies have suggested a number of promising approaches to improving the technique of circulatory arrest.

Adenosine Triphosphate↗
PubMed1993

Repair of double aortic arch associated with D-transposition of the great arteries.

D-transposition of the great arteries is infrequently associated with anomalies of the aortic arch. We report a rare case of double aortic arch associated with D-transposition of the great arteries. The diagnosis was made by angiography and transthoracic echocardiography. The patient underwent a successful simultaneous arterial switch operation and division of the vascular ring through a median sternotomy incision.

Aorta, Thoracic↗
PubMed1993

Fate of small homograft conduits after early repair of truncus arteriosus.

Neonatal repair of truncus arteriosus is being performed in a number of centers, often with the use of small homograft conduits. The fate of the homograft and the risk of replacement were the subjects of this study. Between January 1987 and October 1991, 43 infants aged less than 3 months (range, 3 to 90 days) underwent primary repair of truncus arteriosus including implantation of a valved homograft conduit (diameter, 7 to 12 mm). Twenty-nine had follow-up of more than 6 months (range, 6 to 65 months; mean, 21.9 months). After a mean period of 31 months (range, 8 to 65 months), 7 patients showed obstruction with right ventricular pressures at least 75% systemic and underwent either a conduit change (n = 5) or a patch augmentation (n = 2). Mean cardiopulmonary bypass time at reoperation was 99 minutes; mortality was zero. Five other children are known to have a right ventricular pressure of 50% to 60% systemic, 2 having undergone balloon dilation. Statistical comparison of the patients with conduit reoperation or high right ventricular pressure (n = 12) with the rest of the population (n = 17) revealed an elevated pulmonary artery to right ventricular pullback gradient on postoperative day 1 after the repair (7.7 versus 1.3 mm Hg; p = 0.001) and choice of an aortic over a pulmonary homograft (100% versus 64.7%; p = 0.065) as significant risk factors. Age and weight at repair, postoperative pulmonary artery pressure, length of follow-up, and size of the homograft showed no significant differences between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1993

Echocardiographic predictors of left ventricular outflow tract obstruction after repair of interrupted aortic arch.

OBJECTIVES: This study was designed to identify preoperative echocardiographic predictors of left ventricular outflow tract obstruction after repair of interrupted aortic arch and ventricular septal defect closure. BACKGROUND: Left ventricular outflow tract obstruction becomes apparent in nearly 50% of patients after repair of interrupted aortic arch and ventricular septal defect closure but is seldom recognized preoperatively. METHODS: We analyzed the preoperative echocardiograms of all patients with interrupted aortic arch who had postoperative echocardiographic or catheterization data available. Thirty-seven infants (aged 1 day to 10 months, median 5 days) were included. Off-line measurements were performed on hard copies of selected images. The cross-sectional area (indexed to body surface area) and diameters (indexed to the square root of body surface area) of the left ventricular outflow tract; ascending and descending aorta; ventricular septal defect; and mitral, aortic and pulmonary valves were compared with outcome by using analysis of variance. Outcome was classified according to development of postoperative left ventricular outflow tract Doppler gradient (Group 1 < or = 20 mm Hg, Group 2 > 20 mm Hg). RESULTS: The cross-sectional area of the left ventricular outflow tract was significantly smaller in patients who did than in those who did not develop subaortic obstruction ([mean +/- SD] 0.64 +/- 0.25 vs. 1.7 +/- 1.01 cm2/m2, p < 0.004). Left ventricular outflow tract and aortic valve diameters and aortic valve area were not predictive of postoperative left ventricular outflow tract obstruction. Incidence of postoperative left ventricular outflow tract obstruction was lower (p < 0.03) in interrupted aortic arch type A (0 of 6) than in type B (15 of 31). The incidence of aberrant right subclavian artery was lower (p < 0.02) in Group 1 (6 of 22) than in Group 2 (10 of 15). CONCLUSIONS: The preoperatively measured cross-sectional area of the left ventricular outflow tract is significantly smaller in patients with interrupted aortic arch who develop subaortic obstruction postoperatively, with a left ventricular outflow tract area < or = 0.7 cm2/m2 being a sensitive predictor. Aortic arch anatomy (i.e., type of interrupted aortic arch and presence of aberrant right subclavian artery) is also predictive of postoperative left ventricular outflow tract obstruction, possibly by influencing the volume of blood flow across the left ventricular outflow tract. These data should enable preoperative identification of infants who may require surgical relief of subaortic stenosis.

Aorta, Thoracic↗
PubMed1993

Reliability of Doppler color flow mapping in the identification and localization of multiple ventricular septal defects.

The purpose of this study was to compare Doppler color flow mapping with angiography and surgical observation for detection of multiple ventricular septal defects (VSDs). Only patients with elevated pulmonary ventricular pressure were included. Among 137 patients with VSDs, 38 multiple defects were identified in 25 patients echocardiographically, 34 multiple defects in 24 patients angiographically, and 21 multiple defects in 17 patients surgically. Using surgical observation as the reference standard, the sensitivity of echocardiography for identifying patients with multiple VSDs was 17 of 17 (100%) and for angiography 15 of 17 (88%). The sensitivity of echocardiography for identifying all multiple VSDs seen at operation was 19 of 21 (90%) and of angiography was also 19 of 21 (90%). In many patients, use of both techniques may no longer be necessary.

Angiography↗
PubMed1993

Surgical repair of complete atrioventricular canal defects in infancy. Twenty-year trends.

Case histories of 301 patients with complete atrioventricular canal defect presenting to our institution in infancy between January 1972 and January 1992 were reviewed with the purpose of identifying the factors responsible for the observed improvement in perioperative mortality over this time period. A retrospective analysis of hospital records examined 46 patient-related, morphologic, procedure-related, and postoperative variables for associations with perioperative death and reoperation. Operative mortality decreased significantly over the period of the study from 25% before 1976 to 3% after 1987 (p < 0.0001). A number of the 46 variables examined showed trends over time that were similar to that for mortality. Palliative procedures decreased over time. Reoperation for most residual lesions also decreased to the degree that they were essentially eliminated in recent years. The exception to this was reoperation for postoperative left atrioventricular valve regurgitation, which also decreased but remained at 7% in recent years. Both technical and support-related procedural variables showed no trends over time, with the exception of the performance of left atrioventricular valve annuloplasty, which increased over time. Closure of the left-sided cleft was performed in 61% of the patients, with no trend over time. Annuloplasty and cleft closure were not associated with less postoperative left atrioventricular valve regurgitation, fewer reoperations, or lower mortality. Multivariate logistic regression analysis identified only earlier year of operation, the presence of double-orifice left atrioventricular valve, and postoperative residual regurgitation of the left atrioventricular valve as risk factors for death. Experience-related improvements in technical precision achieved over time best account for the reduction in the rate of reoperation for most types of residual lesions and also for the reduction in mortality. The only residual lesion that has not been essentially completely eliminated is left atrioventricular valve regurgitation, with reoperation for this lesion having been reduced in recent years, but not eliminated. Improved understanding of the structural and functional variability of the atrioventricular valve in this lesion may be necessary before postoperative dysfunction of this valve can be completely eliminated.

Child↗
PubMed1993

Early bidirectional cavopulmonary shunt in young infants. Postoperative course and early results.

BACKGROUND: Despite the recent wide applicability of the bidirectional cavopulmonary shunt, there is limited reported experience in performing these shunts in infants 6 months or younger. METHODS AND RESULTS: Before October 1992, 17 consecutive infants aged 4.2 to 6.5 months (median, 6.1 months) underwent bidirectional cavopulmonary shunts. The diagnoses were hypoplastic left heart syndrome (n = 7), single right ventricle (n = 5), and single left ventricle (n = 5). All but 2 patients had prior palliative surgery. The bidirectional cavopulmonary shunt was performed early on an elective basis in 9 patients; the remaining patients had progressive cyanosis (6 patients), severe ventricular failure (1 patient), and coexisting restrictive bulboventricular foramen (1 patient). The median preoperative pulmonary arterial pressure and pulmonary vascular resistance were 15 mm Hg and 2.3 U.m2, respectively. One patient died; the overall hospital survival was 94%. The most common postoperative problem was transient systemic hypertension, observed in 14 (88%) of 16 survivors. Systemic arterial oxygen saturation increased from a median of 75% before surgery to a median of 85% after surgery (P < .05). The median hospital stay was 6 days. There were no late deaths during follow-up (median, 12.4 months). At postoperative cardiac catheterization performed in 9 of 16 survivors, there was no evidence of severe hypoxemia, shunt narrowing, or pulmonary arteriovenous fistulas. Of the 16 survivors, 6 have had a subsequent Fontan operation at a median age of 1.9 years; there were 5 survivors. CONCLUSIONS: Early bidirectional cavopulmonary shunt in young infants has shown encouraging early results and provides improved oxygenation with low morbidity and mortality. We speculate that an early bidirectional cavopulmonary shunt on an elective basis may reduce the deleterious sequelae of chronic hypoxemia, long-term ventricular volume overload, and repeated palliative procedures, thus yielding a more suitable Fontan candidate.

Arteriovenous Shunt, Surgical↗
PubMed1993

Intraoperative device closure of ventricular septal defects.

BACKGROUND: Surgical repair of muscular ventricular septal defects (VSDs) has been associated with significant morbidity and mortality when the defects are multiple, associated with complex cardiac lesions, or requiring left ventriculotomy. Transcatheter VSD closure may be difficult in patients weighing less than 7 kg or those with limited vascular access. We attempted intraoperative device closure of muscular VSDs during surgical repair of associated lesions. METHODS AND RESULTS: We considered intraoperative umbrella closure in 10 patients, 8 with additional complex heart lesions. "Swiss cheese" defects were present in 4. Median patient age was 4.7 months. Device closure was not attempted in 1 patient due to an inadequate septal rim. Nine umbrellas, 12 to 40 mm in diameter, were positioned to straddle the septum in all 9 patients. There were 3 early deaths, 2 in patients who were moribund preoperatively. The third was due to severe ventricular dysfunction. Among the 6 survivors, 3 had a Qp:Qs < or = 2 and right ventricular or pulmonary artery pressure less than half systemic. These patients had no further intervention. The other 3 had a Qp:Qs > 2. One died unexpectedly 5 weeks after cardiac surgery. The other 2 had subsequent closure of residual VSDs. All 5 survivors are well at follow-up of 8 to 25 months. CONCLUSIONS: Intraoperative umbrella VSD closure appears less successful than VSD closure in the catheterization laboratory. In selected patients, particularly very small infants, intraoperative device placement may be advantageous. Completeness of closure is difficult to assess intraoperatively.

Cardiac Catheterization↗
PubMed1993

Relation of pH strategy and developmental outcome after hypothermic circulatory arrest.

To examine whether pH management during core cooling is a risk factor for adverse developmental outcome, we studied 16 children with transposition of the great arteries and intact ventricular septum who underwent a Senning procedure in infancy (median age 32 days, range 2 to 154 days) between 1983 and 1988. Information was collected retrospectively on many aspects of perfusion, including lowest carbon dioxide tension during core cooling, duration of core cooling, and duration of circulatory arrest. The pH strategy changed from pH-stat to alpha-stat in 1985, resulting in a wide range of pH values and carbon dioxide tension (34 to 76 mm Hg) during the study period. All children had rapid core cooling to a rectal temperature of 19.8 degrees +/- 2.7 degrees C (mean +/- standard deviation) and a tympanic temperature of 16.6 degrees +/- 3.0 degrees C. Development was assessed at median age 48.0 (11 to 79) months with the Bayley Scales (n = 4, children younger than 30 months) or the McCarthy Scales (n = 12, children older than 30 months). The mean core-cooling duration was 14.5 +/- 6.2 minutes, circulatory arrest time was 43.4 +/- 6.6 minutes, and total bypass plus circulatory arrest time was 89.7 +/- 12.7 minutes. Lower carbon dioxide tension (alpha-stat) before onset of circulatory arrest was associated with worse developmental outcome (r = 0.71, p = 0.002). This relationship remained highly significant when we controlled for sociodemographic and intraoperative variables. including core-cooling time, circulatory arrest time, and total elapsed time. Duration of circulatory arrest was not associated with developmental outcome. We conclude that when relatively rapid core cooling is used to achieve hypothermia before circulatory arrest in young infants, a more alkaline pH strategy such as alpha-stat may result in less effective cerebral protection.

Carbon Dioxide↗
PubMed1993

Recovery of cerebral blood flow and energy state in piglets after hypothermic circulatory arrest versus recovery after low-flow bypass.

A miniature piglet model that replicates clinical hypothermic (14 degrees C nasopharyngeal) circulatory arrest and low-flow (50 ml/kg per minute) bypass was used to study carotid blood flow with electromagnetic flow probe, cerebral blood flow by microsphere injection, cerebral metabolic rate by arteriovenous oxygen and glucose extractions, lactate production by cerebral arteriovenous difference, and cerebral edema. Data from five animals that underwent circulatory arrest and five animals that underwent low-flow bypass (aged 28.8 +/- 0.4 [mean +/- standard error of the mean] days) were analyzed. The duration of circulatory arrest and low-flow bypass was 1 hour. In a parallel study with the same animal model, phosphorus 31 magnetic resonance spectroscopy was used to assess cerebral phosphocreatine, nucleoside triphosphate (adenosine triphosphate), and intracellular pH. Five animals (aged 31.8 +/- 1.1 days) underwent circulatory arrest, and five underwent low-flow bypass. A brief phase of hyperemic carotid blood flow was seen immediately after the onset of reperfusion in the circulatory arrest group but not in the low-flow group. In the circulatory arrest and low-flow bypass groups, cerebral blood flow (percentage of baseline 71.2% +/- 8.3% and 69.1% +/- 5.8%, respectively), cerebral oxygen consumption (45.6% +/- 10.0%, 44.5% +/- 7.6%), and cerebral glucose consumption (31.5% +/- 30.7%, 83.5% +/- 24.2%) remained depressed after 45 minutes of reperfusion and rewarming to normothermia. However, after 3 more hours of pulsatile normothermic reperfusion, cerebral oxygen consumption and cerebral glucose consumption had returned to baseline. Phosphocreatine, adenosine triphosphate, and pH were maintained at or above baseline levels throughout low-flow bypass and throughout 3 hours of normothermic reperfusion. In contrast, both phosphocreatine and adenosine triphosphate became undetectable 32 +/- 3.7 minutes after onset of circulatory arrest. During and early after circulatory arrest, pH decreased to a minimum of 6.506 +/- 0.129 at 40 minutes after reperfusion. After 3 hours of normothermic reperfusion, phosphocreatine and adenosine triphosphate recovered to 98.6% +/- 9.0% and 90.1% +/- 13.5% of baseline, respectively, and pH was 7.087 +/- 0.051, similar to baseline (7.1755 +/- 0.041). In the low-flow bypass group, the disparity between the depressed level of cerebral oxygen consumption and normal high-energy phosphate levels may reflect incomplete cerebral rewarming or decreased energy consumption. In the circulatory arrest group, the parallel recovery of oxygen consumption and high-energy phosphates eventually achieving baseline levels suggests that the degree of hypothermia used provides adequate protection for acute cerebral recovery after 1 hour of circulatory arrest.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗
PubMed1993

Mechanical durability of pulmonary allograft conduits at systemic pressure. Angiographic and histologic study in lambs.

We examined the mechanical durability of cryopreserved pulmonary allograft conduits at systemic pressure in lambs. Composite valveless tube grafts made of cryopreserved pulmonary allograft and a length of Dacron tube were implanted in the thoracic aortic position in 10 lambs (aged 1 month, mean weight 11.4 kg). The pulmonary allografts were harvested from similar-sized lambs (aged 1 month, mean weight 10.5 kg) at 0 to 48 hours postmortem and were cryopreserved. Recipient sheep were catheterized at 1 week (baseline) and at 1, 4, 6, 9, and 12 months postoperatively to allow changes in the diameters of the grafts to be followed up by angiography. Samples of the grafts were examined histologically at the time of harvest, at implantation after cryopreservation and thawing, and at the end of the study. At the postoperative baseline study, the pulmonary allografts had almost doubled (mean 21.1 mm) their implantation diameters (unpressurized mean 12.6 mm). During the 12-month study period, the allografts further increased their angiographic diameter by 36.2% compared with baseline (p < 0.01). One animal died at 3 1/2 months postoperatively and was found to have an aneurysm of the allograft. Five of the remaining eight lambs showed aneurysmal dilatation (more than 40% increase in diameter relative to pressurized baseline) at 12 months. Postmortem study revealed disruption at the suture line between allograft and Dacron in these five recipients. Histologic study showed much less calcification than was seen in our previous study of aortic allografts. There was loss of most of the smooth muscle, intimal and adventitial fibrous proliferation, and occasional dense lymphocytic infiltrates associated with foci of persistent smooth muscle cells. Time of harvest after donor death did not affect the histologic appearance after 12 months' implantation. Pulmonary allografts dilate substantially at systemic pressure. This characteristic has the benefit of allowing progressive enlargement with time as a recipient grows but also carries the risk of aneurysm formation, particularly pseudoaneurysm at the suture line when anastomosed with a noncompliant Dacron prosthesis.

Anastomosis, Surgical↗
PubMed1993

Repair of truncus arteriosus in the neonate.

From September 1986 through December 1991, 63 patients with truncus arteriosus underwent surgical repair. The management approach evolved over the period of the study from elective primary repair at 3 months of age to elective primary repair in the early neonatal period. Thirty variables were examined as potential risk factors for the outcome events of death, reoperation, and presence of pulmonary vascular morbidity. According to both univariate and multivariate techniques, severe truncal valve regurgitation, interrupted aortic arch, coronary artery anomalies, and age at repair greater than 100 days were important risk factors for perioperative death. In the 33 patients without these risk factors, early survival was 100%. In the 30 patients with one or more of these risk factors, survival was 63%. Pulmonary hypertensive episodes were fewer, and duration of ventilator dependence and pulmonary artery pressure were significantly less in patients undergoing the operation before 30 days of age. Seven patients required reoperation for right ventricular outflow tract obstruction at a mean follow-up time of 23.4 months, with no deaths. In conclusion, interrupted aortic arch, severe truncal valve insufficiency, coronary anomalies, and repair later than 100 days of age were risk factors for death after repair of truncus arteriosus. In the absence of these associations, truncus arteriosus can be repaired with excellent surgical outcome in the neonatal and early infancy period. Repair in the early neonatal period reduces the prevalence of postoperative pulmonary vascular morbidity.

Age Factors↗
PubMed1992

Temperature monitoring during CPB in infants: does it predict efficient brain cooling?

We examined jugular venous oxygen saturation data in 17 pediatric patients less than 1 year of age undergoing hypothermic cardiopulmonary bypass (CPB). Jugular venous oxygen saturations (JvO2SATS) were measured before bypass and during the active core cooling portion of CPB. The study intervals during CPB included 1 minute after initiation of CPB, at a tympanic membrane temperature of 15 degrees C, and at a rectal temperature of 15 degrees C. During these measurement intervals, there were no significant changes in mean arterial pressure, pump flow rate, arterial oxygen saturation, mixed venous oxygen saturation, carbon dioxide tension, or hematocrit. Six of the 17 patients (29%) demonstrated a significantly lower JvO2SAT (87.1% +/- 6.3% versus 98.1% +/- 0.9%) at a tympanic membrane temperature of 15 degrees C. Patients demonstrating jugular venous desaturation could not be predicted from continuous monitoring of tympanic membrane and rectal temperatures or through on-line measurements of mixed venous oxygen saturation. Low JvO2SAT suggests higher levels of cerebral metabolism and cerebral uptake of oxygen. In the presence of deep hypothermic CPB and stable anesthetic levels, the most likely cause of a low JvO2SAT is inadequate cerebral cooling. We believe JvO2SAT monitoring may be an important adjunct to conventional temperature monitoring in the patient undergoing deep hypothermic CPB or total circulatory arrest.

Body Temperature↗
PubMed1992

Effect of baffle fenestration on outcome of the modified Fontan operation.

BACKGROUND: The "fenestrated Fontan" (surgical baffle fenestration followed by transcatheter test occlusion and permanent closure after postoperative recovery) was adopted in an effort to reduce perioperative mortality and morbidity. This study assesses the effect of baffle fenestration on outcome. METHODS AND RESULTS: Patients having a modified Fontan operation with a cavocaval baffle and cavopulmonary anastomosis were retrospectively selected for study. Those with baffle fenestration (n = 91) were compared with those without baffle fenestration (n = 56) with respect to preoperative risk factors, age, anatomy, surgical date, and presence or absence of a previous bidirectional cavopulmonary anastomosis. Outcome variables were failure (death or take-down) and duration of postoperative pleural effusions and hospitalization. Survival and clinical status after hospital discharge were ascertained. The two groups did not appear to differ with respect to age or anatomic diagnosis. Patients having baffle fenestration were at significantly greater preoperative risk by univariate and multivariate analysis (p < 0.01). Operative failure was low in both groups (11% without and 7% with baffle fenestration, p = NS). Durations of pleural effusions and hospitalization were significantly shorter with baffle fenestration (p < 0.01). Neither date of surgery nor a previous bidirectional cavopulmonary anastomosis appeared to contribute to improved outcome. Patients with baffle fenestration had lower postoperative systemic venous pressure (p < 0.01). There were no late deaths. Functional status in both groups is good (82% in New York Heart Association class I). CONCLUSIONS: Baffle fenestration is associated with low mortality, significantly less pleural effusion, and significantly shorter hospitalization among high-risk patients having a modified Fontan operation.

Cardiac Surgical Procedures↗
PubMed1992

Age-dependent ventricular response to pressure overload. Considerations for the arterial switch operation.

Success with the arterial switch operation for D-transposition of the great arteries and the concept of left ventricular suitability for systemic work stimulated this literature review of the age-dependent mechanisms in normal cardiac growth and pressure-induced left ventricular hypertrophy. Normal postnatal myocardial growth is markedly influenced by hemodynamic factors. It consists of an early hyperplastic phase of both myocytes and capillaries that is followed by a myocyte hypertrophic phase. Similarly, imposition of a pressure overload induces both myocyte hyperplasia/hypertrophy and increased angiogenesis in neonates, but only myocyte hypertrophy at a later age. The functional consequences of ventricular hypertrophy are the result of adaptive and nonadaptive changes resulting from the overload stimulus, for example, induction of protooncogene expression, myosin isoenzyme shifts, degree of coronary perfusion, responsiveness to beta-adrenergic stimulation, and myocyte capacity to re-accumulate or sequester cytosolic calcium. Strikingly, both the capacity and the rapidity of left ventricular hypertrophy decrease with increasing age. This experimental information supports the current use of primary arterial switching for neonates with D-transposition of the great arteries and the use of "rapid" two-stage arterial switching in infants more than 3 to 4 weeks of age; it raises some concern about the practice of late retraining of the left ventricle in cases of failed atrial inversion operation.

Age Factors↗
PubMed1992

Course in the intensive care unit after 'preparatory' pulmonary artery banding and aortopulmonary shunt placement for transposition of the great arteries with low left ventricular pressure.

BACKGROUND: In patients with transposition of the great arteries with low left ventricular pressure, pulmonary artery banding with aortopulmonary shunt placement has been advocated to "prepare" the left ventricle for systemic work before an arterial switch operation. METHODS AND RESULTS: In 28 patients, this preparatory procedure was performed with one death. A successful arterial switch operation was performed at a median of 7 days later in 24 of 27 survivors; one child had a Senning performed, and two others died. During this interval period, the left ventricular-to-right ventricular pressure ratio increased from 48 +/- 8% to 98 +/- 19%, and left ventricular mass (indexed for body surface area) increased from 46 +/- 17 to 72 +/- 23 g/m2. After the preparatory procedure, the initial postoperative period was frequently characterized by a low-output syndrome of variable length and severity. Prolonged mechanical ventilation, extended inotropic support, and/or a significant metabolic acidosis was present in 21 of 28 patients in the immediate postoperative period. CONCLUSIONS: The low-output syndrome is most likely due to a combination of acute (fixed) right ventricular volume overload from the shunt and acute (transient) left ventricular dysfunction from the pulmonary artery band. This low-output syndrome should be anticipated following the preparatory procedure.

Blood Vessel Prosthesis↗