Right ventricle to pulmonary artery conduit improves outcome after stage I Norwood for hypoplastic left heart syndrome

The effect of left ventricular size on right ventricular hemodynamics in pediatric survivors with hypoplastic left heart syndrome

BACKGROUND

Outcome status in patients with hypoplastic left heart syndrome (HLHS) is partially dependent on right ventricular (RV) systolic function. In other disease states, ventricular function is impacted by anatomy and physiology of the contralateral ventricle. In HLHS, it is suggested that a relatively larger left ventricular (LV) size may negatively impact RV function because it becomes a "passenger" without providing any systolic or diastolic physiologic benefit. The purpose of this study was to determine whether LV size adversely affects RV systolic function in surviving patients with HLHS.

METHODS

The hospital database was searched for all patients with HLHS and technically adequate echocardiograms born in the last 6 years and who had survived at least the Norwood procedure. LV size was assessed by echocardiographic measurement of LV end-diastolic short-axis and apical area. RV function was assessed by short-axis and apical fractional area change as well as the myocardial performance index (Tei). Measurements were made at up to 4 time points depending on duration of follow-up (1 - pre-Norwood; 2 - pre-Glenn; 3 - pre-Fontan; and 4- post-Fontan).

RESULTS

A total of 48 patients were studied. LV size showed sufficient variability in the patient population (1.0-21 cm(2)/body surface area, pre-Norwood). RV function tended to worsen across the time periods but these changes did not reach statistical significance. Regression analysis showed no effect of LV size on RV function before Norwood operation. Significant correlations existed between LV size indices and RV functional indices before Glenn shunt but these were inconsistent in the direction of their effect. Only before Fontan operation did the correlation between LV size and RV function become both consistent and statistically significant; specifically larger LV size correlated significantly with poor RV systolic function (short-axis RV fractional area change vs LV area r = -0.4, P = .03 and RV Tei vs LV area r = 0.5, P = .02). These relationships were not apparent after Fontan operation.

CONCLUSION

In surviving patients with HLHS, larger LV size does not seem to negatively impact RV function before or after Norwood procedure nor does it seem to have an adverse effect on RV function chronically (after Fontan). However, further study with larger population size will be necessary to see whether these findings remain negative and are true for nonsurvivors as well.

Impact of placing a conduit from the right ventricle to the pulmonary arteries as the first stage of further palliation in the Norwood sequence for hypoplasia of the left heart

OBJECTIVE

We describe the experience from a single institution with the Norwood sequence of palliation for hypoplasia of the left heart, emphasizing complications related to placement of a conduit from the right ventricle to the pulmonary arteries and their management.

METHODS

Between November, 2002 and January, 2006, we palliated 32 patients with hypoplastic left heart syndrome or its variants by placing a conduit from the right ventricle to the pulmonary arteries. We reviewed retrospectively the charts and angiograms from these patients.

RESULTS

Hospital survival after construction of the conduit was 90.6%. There were 3 interstage deaths, of which 2 were likely due severe obstruction of the conduit. Stents were implanted into the proximal or medial portions of the conduits of 3 patients. Early revision of the distal anastomosis, and shortening the conduit, was performed early postoperatively in 2 patients. So far, 24 out 26 survivors of the first stage underwent a bi-directional cavopulmonary anastomosis after a mean interval of 4.3 plus or minus 1.4 months. Of these, 3 required a semi-urgent second stage of palliation because of worsening cyanosis, with one patient dying after the second stage. Completion of the Fontan circulation by insertion of an extracardiac conduit was performed in 8 patients at the mean age of 19.8 plus or minus 2.2 months. We were able to achieve biventricular repair in 1 patient, with aortic atresia, hypoplastic arch and ventricular septal defect, 4.3 months after the initial palliative procedure. Overall survival of the whole cohort of 32 patients was 78.9%, plus or minus 7.8%, at 5 months, and 74.3%, plus or minus 8.6%, up to 25 months.

CONCLUSIONS

The introduction of the conduit placed from the right ventricle to the pulmonary arteries has led to an improved outcome in the complex entity of hypoplastic left heart syndrome and its variants. Stenosis of the conduit, nonetheless, may account for significant interstage morbidity, and often requires intervention or early installation of the second stage of palliation.

Hypoplastic left heart syndrome

Hypoplastic left heart syndrome(HLHS) refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. HLHS has been reported to occur in approximately 0.016 to 0.036% of all live births. Newborn infants with the condition generally are born at full term and initially appear healthy. As the arterial duct closes, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to congestive heart failure. The embryologic cause of the disease, as in the case of most congenital cardiac defects, is not fully known. The most useful diagnostic modality is the echocardiogram. The syndrome can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation. Differential diagnosis includes other left-sided obstructive lesions where the systemic circulation is dependent on ductal flow (critical aortic stenosis, coarctation of the aorta, interrupted aortic arch). Children with the syndrome require surgery as neonates, as they have duct-dependent systemic circulation. Currently, there are two major modalities, primary cardiac transplantation or a series of staged functionally univentricular palliations. The treatment chosen is dependent on the preference of the institution, its experience, and also preference. Although survival following initial surgical intervention has improved significantly over the last 20 years, significant mortality and morbidity are present for both surgical strategies. As a result pediatric cardiologists continue to be challenged by discussions with families regarding initial decision relative to treatment, and long-term prognosis as information on long-term survival and quality of life for those born with the syndrome is limited.

Norwood procedure for hypoplastic left heart syndrome: BT shunt or RV-PA conduit?

BACKGROUND

The Norwood procedure is the first stage palliative procedure for hypoplastic left heart syndrome (HLHS). Traditionally the pulmonary circulation has been supplied via a modified Blalock Taussig (BT) shunt but a recent modification, adopted in some UK centres, substitutes a conduit between right ventricle and pulmonary arteries (RV-PA conduit). It is argued that this will result in a more favourable balance between pulmonary and systemic circulations.

AIM

To compare the early postoperative haemodynamic profile between patients undergoing a BT shunt or an RV-PA conduit.

METHODS

Retrospective review in a tertiary referral PICU of 51 children with HLHS undergoing the Norwood procedure with either a BT shunt (Group 1; n = 23) or an RV-PA conduit (Group 2; n = 28). Data items were extracted at 10 set time points in the initial 96 h, postoperatively.

RESULTS

Diastolic BP was significantly lower in Group 1 (p<0.001) with a trend towards a higher systolic BP and no difference in mean BP. No between-group differences were found in markers of pulmonary blood flow (PaO2, PaCO2, PaO2/FiO2 ratio), or in markers of systemic blood flow (blood lactate, oxygen extraction ratio), or in estimated ratio of pulmonary:systemic blood flow (Qp:Qs). Despite lower diastolic blood pressure in Group 1 renal and hepatic function did not differ over five post-operative days between groups.

CONCLUSIONS

With the exception of a higher diastolic blood pressure in the RV-PA conduit group, we found no difference in the early haemodynamic profile between patients undergoing an RV-PA conduit or a BT shunt.

Does a ventriculotomy have deleterious effects following palliation in the Norwood procedure using a shunt placed from the right ventricle to the pulmonary arteries?

INTRODUCTION

A recent modification to the Norwood procedure involving a shunt placed directly from the right ventricle to the pulmonary arteries may improve postoperative haemodynamics. Concerns remain, however, about the potential problems produced by the required ventriculotomy.

METHODS

We compared 76 patients with hypoplastic left heart syndrome who underwent the Norwood procedure, 35 receiving a modified Blalock-Taussig shunt and the remaining 41 a shunt placed directly from the right ventricle to the pulmonary arteries. We reviewed their subsequent progress through the second stage of palliation. A single observer graded right ventricular function, and the severity of tricuspid regurgitation, based on blinded review of the most recent echocardiograms prior to the second stage of palliation.

RESULTS

At the time of catheterization prior to the second stage, patients with a shunt placed from the right ventricle to the pulmonary arteries, rather than a modified Blalock-Taussig shunt, had higher arterial diastolic blood pressure, at 44 versus 40 millimetres of mercury, p equal to 0.02, lower ventricular end diastolic pressures, at 8 versus 11 millimetres of mercury, p equal to 0.0002, and larger pulmonary arteries as judged using the Nakata index, at 270 versus 188 millimetres squared per metres squared, p equal to 0.009. There was no difference in qualitative ventricular systolic function or tricuspid regurgitation between groups. No differences were found between groups during the hospitalization following the second stage of palliation. A trend towards improved survival to the second stage was seen following the construction of a shunt from the right ventricle to the pulmonary arteries.

CONCLUSIONS

Construction of a shunt from the right ventricle to the pulmonary arteries is associated with lower right ventricular end diastolic pressures, larger pulmonary arterial size, and higher systemic arterial diastolic pressures. No apparent deleterious effects of the right ventriculotomy were observed in terms of qualitative ventricular systolic function or tricuspid regurgitation.

The modified Blalock-Taussig shunt versus the right ventricle-to-pulmonary artery conduit for the Norwood procedure

The initial Norwood procedure remains the highest risk operation for the staged repair of univentricular congenital malformations with associated systemic outflow obstruction. The modified Blalock-Taussig shunt (MBTS) has been implicated as a major cause of not only the operative mortality, but also associated morbidity and interstage attrition. The etiology of these events has often been attributed to the diastolic runoff and "coronary steal" associated with the MBTS, in addition to the delicate balance between systemic and pulmonary blood flow that characterizes all systemic-to-pulmonary artery shunts. Recently, there has been renewed interest in the right ventricle-to-pulmonary artery conduit as a source of pulmonary blood flow for the Norwood procedure as a potential method for minimizing the negative aspects of the MBTS. The current literature is contradictory, retrospective, and predominantly historically controlled. The Trial of Right Ventricular vs Modified Blalock-Taussig Shunt in Infants with Single Ventricle Defect Undergoing Staged Reconstruction, a randomized controlled clinical trial comparing the two techniques, is ongoing and may provide answers to this controversy.

New developments in the treatment of hypoplastic left heart syndrome

In the current decade, the prognosis of newborns with hypoplastic left heart syndrome, previously considered a uniformly fatal condition, has dramatically improved through refinement of rapidly evolving treatment strategies. These strategies include various modifications of staged surgical reconstruction, orthotopic heart transplantation, and hybrid palliation using ductal stenting and bilateral pulmonary artery banding. The variety of treatment approaches are based on different surgical philosophies, and each approach has its unique advantages and disadvantages. Nonetheless, multiple experienced centers have reported improved outcomes in each one of those modalities. The purpose of this review is to outline recent developments in the array of currently available management strategies for neonates with hypoplastic left heart syndrome. Because the vast majority of deaths in this patient population occur within the first months of life, the focus of the review will be evaluation of the impact of these management strategies on survival in the neonatal and infant periods.

Results of staged palliation for hypoplastic left heart syndrome: a complete population-based series

AIM

To study the outcome of staged palliation for classic hypoplastic left heart syndrome.

METHODS

Retrospective chart review. Risk factors for mortality were analysed using Cox's proportional hazard regression modelling.

RESULTS

From 1993 to 2004, 55 infants underwent Norwood stage I procedure at a median age of 8 d (range 1-19 d). Hospital survival was 39/55 (71%), and there were six late deaths (before stage II). Birthweight, circulatory arrest time and cardiopulmonary bypass time were independent risk factors for stage I hospital mortality (p=0.029, p=0.001 and p=0.003, respectively). Poor right ventricular function prior to stage I was a significant predictor for interstage mortality (p=0.02). Thirty-two patients underwent bidirectional cavopulmonary anastomosis, at a median age of 6.5 mo (range 2.0-9.5 mo), with seven late deaths. Two patients had a heart transplant after stage II. Total cavopulmonary connection (TCPC) was performed in 13 patients, at a median age of 33 mo (range 21-45 mo), without mortality. Kaplan-Meier survival was 58%, 52% and 45% at 6, 12 and 48 mo, respectively.

CONCLUSION

Low birthweight, long time on circulatory arrest and cardiopulmonary bypass were risk factors for stage I mortality. Poor right ventricular function was detrimental to intermediate outcome.

Intensive care course after stage 1 Norwood procedure: are there early predictors of failure?

OBJECTIVE

The purpose of this study was to review the early postoperative course of stage 1 Norwood with Blalock-Taussig shunt (BTS) or right ventricle-to-pulmonary artery conduit (RVPA) and to identify early predictors of failure.

MATERIAL AND METHODS

A retrospective analysis was conducted in 33 consecutive neonates who underwent BTS (n=19) or RVPA (n=14) stage 1 Norwood procedure between 2000 and 2005. Pre-, peri-, and postoperative data included: hourly hemodynamics and blood gases, pulmonary to systemic flow ratio, duration of mechanical ventilatory and inotrope support, intensive care and hospital stay. Failure was defined as death or transplantation.

RESULTS

Thirteen patients failed the procedure (39.4%): 10 BTS (52.6%) and 3 RVPA (21.4%). Failure decreased from 61.1% in 2000-2002 to 13.3% in 2003-2005 and was associated with: low systolic, mean and diastolic blood pressure, urine output, pH, base excess, bicarbonates, and high pulmonary to systemic flow ratio within 24 h postoperatively. Arterial oxygen and CO2 pressure, and oxygen saturation did not differ with failure. RVPA had higher diastolic blood pressure and more stable hemodynamics despite similar pulmonary to systemic flow ratio. Duration of mechanical ventilation, inotrope support, intensive care stay were shorter in RVPA. Postoperative echographic ventricular dysfunction and tricuspid regurgitation grade were correlated with failure.

CONCLUSIONS

Excessive pulmonary to systemic flow ratio and low blood pressure are associated with failure. High diastolic blood pressure more than low pulmonary to systemic flow ratio seems to account for more favorable outcomes in RVPA compared to BTS procedure.

Risk factors for adverse outcomes after surgery on the systemic atrioventricular valve in 109 children

In contrast to older patients, children and young adults rarely have isolated disease of the systemic atrioventricular valve. Stenosis and/or regurgitation of the systemic atrioventricular valve, however, frequently coexist with complex congenital cardiac disease. In addition, most patients undergoing surgery on the systemic atrioventricular valve have had previous intracardiac repairs.

Early postoperative outcomes in a series of infants with hypoplastic left heart syndrome undergoing stage I palliation operation with either modified Blalock-Taussig shunt or right ventricle to pulmonary artery conduit

OBJECTIVE

Previous publications using nonconcurrent series of patients indicate improved survival for patients with hypoplastic left heart syndrome (HLHS) undergoing stage I palliation with a right ventricle to pulmonary artery conduit (NW-RVPA) vs. a modified Blalock-Taussig shunt (NW-BT). We compared postoperative outcomes in a concurrent series of patients with HLHS undergoing an NW-BT procedure vs. NW-RVPA procedure.

DESIGN

Perioperative data from 66 consecutive patients who underwent NW-BT (n = 37) or NW-RVPA (n = 29) procedures were retrospectively analyzed.

SETTING

Cardiac intensive care unit in a tertiary pediatric hospital.

PATIENTS

Charts were reviewed for all patients with the diagnosis of HLHS undergoing the NW-BT or NW-RVPA procedure between January 2002 and December 2003.

RESULTS

Cardiopulmonary bypass time was longer in the NW-BT group than in the NW-RVPA group (152.5 +/- 52.0 vs. 134.5 +/- 36.1 mins; p = .04). Postoperative diastolic pressures were higher and the Pao2 to Fio2 ratio profiles were lower for the NW-RVPA group over the first 72 hrs. Time to sternal closure (2 [1-6] vs. 4 [2-41] days; p = .01), duration of mechanical ventilation (113 [49-386] vs. 136 [84-764] hrs; p = .01), time to establish enteral feeds (4 [2-8] vs. 5 [3-22] days; p = .01), length of intensive care unit stay (11 [7-55] vs. 15 [8-90] days; p = .04), and length of hospital stay (16 [11-67] vs. 27 [12-126] days; p = .01) were shorter in the NW-RVPA group. Postoperative mortality was not significantly different between the NW-RVPA group (7%) and NW-BT group (11%).

CONCLUSION

At an experienced institution with low stage I palliation mortality for HLHS, there were no differences in early morbidity and mortality between the NW-RVPA and NW-BT procedures. The primary advantage of the NW-RVPA procedure may be faster recovery following surgery and earlier discharge from the hospital.

Endovascular stents for relief of cyanosis in single-ventricle patients with shunt or conduit-dependent pulmonary blood flow

Hypoxemia is a significant cause of early and interstage death in patients with single ventricle (SV). Obstruction of Blalock-Taussig shunts (BTS) in patients with SV has traditionally been managed with surgical revision.

PURPOSE

We report on the experience at our institution of deploying endovascular stents within BTS as well as obstructed right-ventricle (RV) to pulmonary artery (PA) conduits in patients with modified Norwood (ie Sano modification).

METHODS

Medical records were reviewed for the time period between January 1, 2002 and November 30, 2005. All patients with SV who presented for intervention for BTS or RV-PA conduit stenosis were reviewed. Specific endpoints reviewed included pre- and post-intervention arterial oxygen saturation, type of intervention (stent vs. ballon dilation), need for subsequent surgical shunt/conduit revision, and interval to second stage palliation.

RESULTS

Fifteen patients with SV underwent intervention for acute cyanosis. Eight patients had BTS, and the other seven patients had RV-PA conduit stenosis. Coronary stents were deployed in 14 of the 15 patients. Four patients also underwent balloon angioplasty of branch PAs. Oxygen saturations improved in all patients, with a mean increase of 13.9% (p = 0.0001). Four patients died before second stage palliation--one due to complications of the catheterization. Of the eleven remaining patients, nine have undergone second stage palliation; interval from intervention to Glenn ranged from 28-205 days (mean 163d). Two patients are awaiting cavo-pulmonary anastamosis.

CONCLUSIONS

Endovascular stenting in this high-risk population is effective at improving oxygen saturation as well as obviating need to surgical shunt/conduit revision.

Staged surgical management of hypoplastic left heart syndrome: a single institution 12 year experience

OBJECTIVE

To describe a 12 year experience with staged surgical management of the hypoplastic left heart syndrome (HLHS) and to identify the factors that influenced outcome.

METHODS

Between December 1992 and June 2004, 333 patients with HLHS underwent a Norwood procedure (median age 4 days, range 0-217 days). Subsequently 203 patients underwent a bidirectional Glenn procedure (stage II) and 81 patients underwent a modified Fontan procedure (stage III). Follow up was complete (median interval 3.7 years, range 32 days to 11.3 years).

RESULTS

Early mortality after the Norwood procedure was 29% (n = 95); this decreased from 46% (first year) to 16% (last year; p < 0.05). Between stages, 49 patients died, 27 before stage II and 22 between stages II and III. There were one early and three late deaths after stage III. Actuarial survival (SEM) was 58% (3%) at one year and 50% (3%) at five and 10 years. On multivariable analysis, five factors influenced early mortality after the Norwood procedure (p < 0.05). Pulmonary blood flow supplied by a right ventricle to pulmonary artery (RV-PA) conduit, arch reconstruction with pulmonary homograft patch, and increased operative weight improved early mortality. Increased periods of cardiopulmonary bypass and deep hypothermic circulatory arrest increased early mortality. Similar factors also influenced actuarial survival after the Norwood procedure.

CONCLUSION

This study identified an improvement in outcome after staged surgical management of HLHS, which was primarily attributable to changes in surgical technique. The RV-PA conduit, in particular, was associated with a notable and independent improvement in early and actuarial survival.

Anesthetic Management of Infants with Palliated Hypoplastic Left Heart Syndrome Undergoing Laparoscopic Nissen Fundoplication

The safety of laparoscopic surgery in infants with single ventricle physiology has been a subject of controversy despite potential benefits over open surgery. We present the anesthetic management of five infants with palliated hypoplastic left heart syndrome that underwent laparoscopic Nissen fundoplication. After anesthetic induction and tracheal intubation, an intraarterial catheter was placed for hemodynamic monitoring. Insufflation pressure was limited to 12 mm Hg and was well tolerated by all patients. There were no intraoperative or postoperative complications. In patients with hypoplastic left heart syndrome, laparoscopic Nissen fundoplication can be safely performed with careful patient selection and close intraoperative monitoring.

The intensive care of infants with hypoplastic left heart syndrome

Until a little over two decades ago, hypoplastic left heart syndrome was considered an inoperable and fatal condition, with most deaths occurring in early infancy, and almost all of those affected dying before their first birthday. However, the advent of surgical palliation and advances in peri-operative care, have offered hope to these patients and their families.

Is routine cardiac catheterization necessary in the management of patients with single ventricles across staged Fontan reconstruction? No!

With the advent of cardiac magnetic resonance imaging and high-resolution echocardiography, cardiac catheterization is unnecessary in clinical protocols in the "routine" single ventricle patient. Catheterization adds little to clinical care in these cases, and there are significant risks and costs associated with it. Catheterization should be reserved for cases in which noninvasive evaluations are equivocal, conflictory, demonstrate deterioration, or needed for intervention. This article delineates the role of noninvasive evaluations relative to cardiac catheterization in the routine single ventricle patient.

Single-ventricle physiology: perioperative implications

Neonates with functional single ventricles have pulmonary and systemic circulations that are supplied in parallel, creating significant cyanosis and ventricular volume overload. The goal of palliative surgery, excluding transplantation, is to convert single-ventricle circulation from a parallel to a series arrangement. This will ultimately require a complete cavopulmonary anastomosis (Fontan-type procedure) in which vena caval blood is rerouted directly into the pulmonary circulation. Various factors require that this palliation occur in stages. Stage I surgery, which is often a Norwood procedure, is done in the neonatal period and stabilizes, but does not resolve, parallel circulation. The tenuous balance between pulmonary and systemic perfusion during this stage makes noncardiac surgery hazardous, and it should be restricted to urgent or emergent indications. Stage II surgery, or partial cavopulmonary anastomosis, relieves both parallel circulation and volume overload, but not cyanosis. Relatively stable hemodynamics during this stage create favorable conditions for elective surgery. Patients who have undergone stage III surgery, the Fontan-type repair, vary in age from toddlers to adults, and in physical status from well-compensated to significantly debilitated. Fontan patients require thorough preoperative assessment when elective surgery is contemplated. Optimal communication between surgeons, anesthesiologists, and cardiologists is essential when caring for the patient with single-ventricle physiology.

Use of a saphenous venous homograft for constructing a conduit from the right ventricle to the pulmonary arteries in the Norwood procedure

The use of a conduit of polytetrafluoroethylene placed between the right ventricle and the pulmonary arteries as source of pulmonary arterial supply during the first stage of palliation for the hypoplastic left heart syndrome has facilitated post-operative management and resulted in decreased mortality. We describe here the use of a cryopreserved saphenous vein inserted in reversed direction to create the connection between the right ventricle and the pulmonary arteries in a neonate with low birth weight undergoing the modified Norwood procedure.

Improved early ventricular performance with a right ventricle to pulmonary artery conduit in stage 1 palliation for hypoplastic left heart syndrome: evidence from strain Doppler echocardiography

OBJECTIVE

To quantify non-invasively right ventricular (RV) performance in infants after stage 1 palliation for hypoplastic left heart syndrome (HLHS).

DESIGN

Prospective, observational study with two dimensional and strain Doppler echocardiography.

SETTING

Single tertiary paediatric cardiology centre.

PATIENTS

Convenience sample of nine consecutive infants with HLHS. Four whose surgery involved a systemic to pulmonary artery (S-PA) shunt were compared with five whose surgery incorporated a right ventricle to pulmonary artery (RV-PA) conduit.

METHODS

Basal RV free wall longitudinal strain rate, systolic strain (epsilon), and RV percentage area change were calculated during a single assessment between 27-50 days after surgery.

RESULTS

Cardiopulmonary bypass time was longer in patients who underwent RV-PA (226 (30) minutes v 181 (18) minutes, p = 0.03), but cross clamp time, duration of ventilation, and inotrope use did not differ. Two patients in the S-PA group died, on days 29 and 60 after surgery. Peak systolic strain rate (-1.24 (0.19)/s v -0.91 (0.21)/s, p = 0.048), peak epsilon (-17.8 (1.8)% v -13.4 (2.0)%, p = 0.01), and RV percentage area change (56 (6)% v 25 (6)%, p < 0.01) were all greater among RV-PA patients. These indices also tended to be greater in survivors as a group. Ventricular loading conditions (oxygen saturations, diuretic treatment, and blood pressure) were similar in both groups.

CONCLUSION

Strain Doppler echocardiography shows improved RV longitudinal systolic contractility in patients during convalescence after the RV-PA modification of stage 1 palliation for HLHS compared with those with an S-PA shunt.

Hemodynamic profile after the Norwood procedure with right ventricle to pulmonary artery conduit

BACKGROUND

The balance of systemic, pulmonary, and coronary blood flow after the Norwood operation for hypoplastic left heart syndrome (HLHS) is critical to early survival. We hypothesized that a right ventricle to pulmonary artery conduit (instead of a systemic to pulmonary artery shunt) would result in hemodynamic changes consistent with a more stable balance of systemic, pulmonary, and coronary perfusion.

METHODS AND RESULTS

Hemodynamic data were obtained during cardiac catheterization before the hemi-Fontan procedure from 24 patients with HLHS; the first 10 had a Norwood operation with a systemic to pulmonary artery shunt, and the latter 14 had the Norwood operation with a right ventricle to pulmonary artery conduit. Significant differences were present, with the right ventricle to pulmonary artery conduit group having a higher aortic diastolic pressure (55 versus 42 mm Hg), a narrowed systemic pulse pressure (43 versus 64 mm Hg), a lower Qp:Qs (0.92 versus 1.42), a higher coronary perfusion pressure (46 versus 32 mm Hg), and a higher ratio of pulmonary artery diameter to descending aorta diameter (1.51 versus 1.37).

CONCLUSIONS

We conclude that, in HLHS after the Norwood operation, the right ventricle to pulmonary artery conduit modification produces hemodynamic changes consistent with improved coronary perfusion and a more favorable distribution of systemic, pulmonary, and coronary blood flow.