Biomedical subjects

William I Norwood

Publications and source records attributed to William I Norwood.

10 recordsLinked to original sources

PubMed2006

Fontan completion in infants.

BACKGROUND: Since the implementation of the Fontan procedure, several clinical factors have been linked to outcome. A study of the outcome after Fontan completion was undertaken with particular attention to the influence of age and cardiac diagnosis. METHODS: Review of all patients (n = 107) undergoing Fontan completion between January 1998 and July 2005 to identify predictors of outcome: early death, prolonged effusions, and prolonged hospital stay. RESULTS: Median age was 13 months (range, 11 to 35) and median weight was 9.4 kgs (6.7 to 15.1). Hypoplastic left heart syndrome was present in 61 patients, and stage I Norwood was the initial palliation in 69. An interim superior cavopulmonary connection was performed in all. A lateral tunnel was used, and a deliberate right to left shunt was created in 99 patients. Mean transpulmonary gradient and pulmonary artery pressure were 5.7 +/- 1.5 mm Hg and 11.6 +/- 2.2 mm Hg, respectively. Median time to extubation was 5 hours (range, 2.5 to 184). Median duration of pleural effusion was 3 days (1 to 58) and was greater or equal to 14 days in 13 patients (12%). Overall mortality was 4.5% (5 of 107). Variables associated with poor outcome included associated noncardiac diagnosis (p < 0.05), elevated transpulmonary gradient (p = 0.03), and pulmonary artery pressure (p < 0.02). Hypoplastic left heart syndrome was the only variable associated with prolonged effusive complications. CONCLUSIONS: Fontan completion can be performed with good results in the first year of life independent of anatomic diagnosis. Significant noncardiac pathology, and a higher pulmonary artery pressure were predictive of worse outcome. Hypoplastic left heart syndrome was associated with prolonged effusions.

Abnormalities, Multiple↗

PubMed2004

Transthoracic access for cardiac catheterization.

Patients who have undergone Fontan palliation for congenital heart disease have limited access to the pulmonary venous atrium. We describe a transthoracic approach to the pulmonary venous atrium for diagnostic and therapeutic cardiac catheterization. A total of 22 patients ranging in age from 14 months to 25 years and weighing 7-68 kg underwent transthoracic catheterization. With the aid of fluoroscopic and angiographic markers, a 20 gauge needle was inserted into the pulmonary venous atrium. A floppy-tipped wire was inserted, and a 4 Fr sheath was placed, upsized as needed. Access to the pulmonary venous atrium was obtained for all patients. Therapeutic procedures were completed for all patients. Transthoracic access to the pulmonary venous atrium in patients who have undergone a Fontan operation is a reliable and rapid mode of access, allowing for complex therapeutic procedures to be performed in the catheterization laboratory, obviating the need for additional open heart surgery.

Adolescent↗

PubMed2004

Right ventricle to pulmonary artery conduit reduces interim mortality after stage 1 Norwood for hypoplastic left heart syndrome.

BACKGROUND: Despite significant improvement in survival after stage 1 Norwood, interim mortality before the second-stage operation remains significant. On the basis of reports of improved circulatory stability associated with the use of a right ventricle to pulmonary artery conduit, the difference between two physiologically different sources of pulmonary blood flow on interim mortality was investigated. METHODS: Data collection of 96 consecutive hospital survivors after stage 1 Norwood surgery was undertaken. The source of pulmonary blood flow was a modified right Blalock-Taussig shunt in 46 (BTS) and a right ventricle to pulmonary artery conduit in 50 patients. The same follow-up protocol was used in both groups. Data analysis was performed to identify variables associated with interim mortality. RESULTS: Analysis of patient-related and procedure-related variables revealed no differences in age, weight, diagnosis, presence of aortic atresia, lowest perioperative pH, duration of cardiopulmonary bypass, circulatory arrest, length of mechanical ventilation, or hospital stay at the time of stage 1 Norwood between groups. Respiratory rate and systolic blood pressure were the only differences detected between groups at the time of discharge. Interim mortality was higher in the Blalock-Taussig shunt group. Statistical analysis identified aortic atresia, a modified Blalock-Taussig shunt, and the presence of perioperative dysrhythmias to be associated with interim mortality. CONCLUSIONS: The use of a right ventricle to pulmonary artery shunt decreases the incidence of interim mortality among hospital survivors after stage 1 Norwood for hypoplastic left heart syndrome. Aortic atresia, the use of a modified Blalock-Taussig shunt, and perioperative dysrhythmias are independently associated with a higher mortality before superior cavopulmonary connection.

Aorta↗

PubMed2004

Total cavopulmonary connection to one lung.

The status of pulmonary circulation is of utmost importance to the success of the modified Fontan operation. Pulmonary artery distortion, hypoplasia of the total pulmonary vascular bed, and elevated pulmonary vascular resistance are all risk factors for adverse outcome after modified Fontan operations. In cases of irreparable acquired atresia of one or the other branch pulmonary artery, clinicians are forced to contemplate the possibility of total cavopulmonary connection to one lung. The combined experience of the authors with 12 cases suggests that the likelihood of operative survival following Fontan's operation to one lung is predicted based on the usual hemodynamic parameters: pulmonary artery pressure and flow, ventricular end diastolic pressure, transpulmonary gradient, and pulmonary vascular resistance. In this series, there were no operative mortalities among patients undergoing Fontan's operation to one lung, all of whom meet the usual criteria for hemodynamic acceptability. There may, however, be a higher incidence of protein-losing enteropathy than in Fontan patients with normal pulmonary vascular beds. All possible means of resuscitating the lost elements of the pulmonary vascular bed and re-establishing pulmonary artery continuity should be attempted to minimize pulmonary vascular capacitance of patients undergoing Fontan's operation. It is clear, however, that the presence of only one pulmonary artery does not in and of itself preclude satisfactory outcome.

Anastomosis, Surgical↗

PubMed2003

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

BACKGROUND: Diastolic run off into the pulmonary circulation and labile coronary perfusion are thought to contribute to morbidity and mortality after the Norwood procedure (NP). We compared outcomes from the use of a RV to PA conduit (RV/PA) or a modified Blalock-Taussig shunt (BTS), physiologically distinct sources of pulmonary blood flow. METHODS AND RESULTS: Review of 56 consecutive patients who underwent a Norwood procedure with a RV/PA (n=36) or a BTS (n=20) between 2000 and 2002. Median age was 4.5 days (range 1 to 40) and median weight was 3.1 kg (range 1.8 to 4.1). The RV/PA was constructed with a 5-mm conduit. Patients in the BTS group received a 4-mm shunt. Comparisons between RV/PA and BTS groups showed no difference for weight, gestational age, prenatal diagnosis, HLHS variant, associated diagnoses, ascending aortic size, ventricular function, AV valve function, and pulmonary venous obstruction. Operative survival was higher with RV/PA [33/36 (92%) versus 14/20 (70%); P=0.05]. Patients with RV/PA had less need for ventilatory manipulations to balance the Qp/Qs (1/36 v/s 8/20; P=0.001), delayed sternal closure (6/36 v/s 7/20; P=0.001), and extracorporeal support (5/36 v/s 7/20; P=0.036). RV/PA patients had more favorable postoperative hemodynamics: higher diastolic blood pressure without changes in systolic blood pressure at 1, 8, 24, 48 hours after the NP (46.3 v/s 39.5; 47.2 v/s 42.1; 46.1 v/s 37.1; and 47.1 v/s 40.2; all P=0.001). CONCLUSIONS: RV/PA simplifies postoperative management and improves hospital survival after NP for HLHS.

Anastomosis, Surgical↗

PubMed2003

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.

Angiography↗

PubMed2003

Pulmonary artery banding before Norwood procedure.

Described here is the use of bilateral pulmonary artery banding as a means to achieve effective restoration of adequate systemic blood flow before a Norwood procedure in two newborns with hypoplastic left heart syndrome who presented after birth with a severe imbalance of Qp/Qs and multiorgan system dysfunction despite usual pharmacologic and ventilatory strategies.

Aortic Valve↗

PubMed2003

Right ventricle to pulmonary artery conduit has a favorable impact on postoperative physiology after Stage I Norwood: preliminary results.

OBJECTIVE: Although significant progress has been made in the perioperative management of neonates with hypoplastic left heart syndrome (HLHS), early survival has plateaued. Moreover, low but important interstage mortality remains unsolved. With a systemic to pulmonary artery shunt, the combination of significant diastolic runoff into the pulmonary circulation, a large volume load on the single ventricle and precarious coronary perfusion result in a delicate physiologic state. In order to minimize these detrimental features, a right ventricle to pulmonary artery (RV to PA) conduit was used as the source of pulmonary blood flow in patients undergoing Stage I Norwood for HLHS. METHODS: Prospective data collection in 15 consecutive patients who underwent Stage I Norwood with an RV to PA conduit. RESULTS: Mean age at surgery was 2.5+/-2 days (range 1-8), mean weight was 2.9+/-0.3 kg (range 2.2-3.6) and mean gestational age was 37 weeks (range 35-40). Anatomic diagnosis was HLHS in all patients, aortic atresia was present in ten. Mean ascending aortic size was 2.9+/-0.9 mm (range 1.5-5). Two patients had moderate atrioventricular valve regurgitation and a genetic syndrome and/or congenital anomaly was present in five patients. Thirteen patients received a 5-mm polytetrafluoroethylene RV to PA conduit, and a 4-mm conduit was used in two. Mean circulatory arrest time was 55+/-6 min. Postoperatively, mean diastolic blood pressure at 1, 8 and 24 h were 47+/-7, 46+/-3 and 43+/-6 mmHg, respectively. Median time to extubation was 23 h (range 9-96) and was less than 24 h in ten patients. Median intensive care unit and hospital stay were 5 days (range 2-19) and 10 days (6-22), respectively. Early mortality was 1/15 (6%). At a mean follow-up of 10.8+/-3.4 months, 12 patients underwent stage II, and three patient have completed the Fontan. CONCLUSION: RV to PA conduit eliminated diastolic runoff into the pulmonary vascular bed resulting in a higher diastolic blood pressure. This physiology appears to be associated with a more stable postoperative course and improved hospital survival.

Blood Vessel Prosthesis Implantation↗

PubMed2003

Risk of seizures in survivors of newborn heart surgery using deep hypothermic circulatory arrest.

OBJECTIVE: To identify pre- and intraoperative variables associated with postoperative acute neurologic events (ANEs), including seizures and coma, in newborn survivors of congenital heart surgery undergoing deep hypothermic circulatory arrest (DHCA), and to risk-stratify this population on the basis of preoperative risk variables for the purpose of designing future neuroprotection trials. METHODS: Survivors of newborn heart surgery who were enrolled in a neuroprotection trial provided a comprehensive database for the evaluation of pre- and intraoperative variables that influence the postoperative occurrence of ANEs (seizures or coma). Patients with hypoplastic heart syndrome were excluded. After characterization of the study population, stepwise logistic regression, combined with clinical judgment, was used to identify variables that were most likely to be associated with an increased risk of seizures in the study sample and that were most likely to be generalized to other populations. RESULTS: Data were available on 164 nonhypoplastic left heart syndrome survivors who underwent newborn heart surgery using DHCA. ANEs occurred in 31 (18.9%) including "seizures alone" (n = 28), "coma alone" (n = 2) or "seizures and coma" (n = 1). A preoperative risk model was constructed demonstrating that infants with a genetic condition and aortic arch obstruction had a 47.8% risk of ANEs compared with all other remaining infants, who had a 9.9% risk. It was also found that prolonged DHCA time (>or=60 minutes) can be a significant risk for infants who have a preexisting genetic condition; however, infants who have genetic conditions and do not undergo prolonged DHCA time or have an aortic arch obstruction are not at increased risk of ANEs. CONCLUSIONS: This study provides new information about the occurrence of ANEs after newborn heart surgery. Seizures or coma, which appeared in approximately 19% of all non-hypoplastic left heart syndrome survivors, were not random events but were significantly associated with specific types of congenital heart disease, the presence of genetic conditions, and prolonged DHCA time. The 3 identified variables permitted individual cases to be assigned to low-, intermediate-, or high-risk categories. Because neonatal seizures are a good surrogate marker of long-term neurologic outcome, these models provide useful information to stratify individual patients for risk of seizures in future neuroprotection trials.

Aortic Arch Syndromes↗

PubMed2002

Stage I palliation for hypoplastic left heart syndrome in low birth weight neonates: can we justify it?

OBJECTIVE: Although the outcome of cardiac surgery in neonates with low birth weight (LBW) has improved, LBW remains a risk factor for surgical palliation. Few surgical series of LBW patients include those with hypoplastic left heart syndrome (HLHS). To identify variables associated with poor outcome in this group, we reviewed our experience with patients with HLHS and LBW who underwent Stage I Norwood palliation. METHODS: Between January 1998 and December 2000, 20 consecutive LBW (<2500 g) neonates with HLHS (n=13) or HLHS variant (n=7) underwent surgical palliation. Retrospective review of all patient data and analysis to identify risk factors was performed. RESULTS: Mean age at surgery was 5.1+/-4.6 days (range 1-17), mean weight was 1.98+/-0.44 kg (range 1.1-2.5), including nine patients under 2 kg. Ten patients were born at <35 weeks gestation. Anatomic diagnosis included HLHS in 13 patients (10 with aortic atresia), unbalanced atrioventricular canal defect in two, double outlet right ventricle in two and other variants in three. Mean ascending aortic size was 4.0+/-1.8 mm (range 1.5-8). Associated cardiac defects were present in three patients, and a genetic syndrome and/or congenital anomaly was present in four of them. Mean circulatory arrest time was 60+/-10 min. Extracorporeal support was used perioperatively in 10 patients. Early mortality was 9/20 (45%). At a mean follow up at 22+/-10 months (range 8-38), six patients underwent stage II, and are awaiting stage III; four patients have completed their Fontan. Anatomic variant, ascending aortic size, prematurity, age at surgery, weight, duration of circulatory arrest, cardiopulmonary bypass time and associated non-cardiac anomalies were not risk factors for poor outcome whereas restrictive pulmonary venous drainage and coronary artery anomalies were associated with decreased survival. CONCLUSION: LBW newborns with HLHS and physiologic variants have an increased early surgical risk but have acceptable intermediate survival rates for subsequent palliation including Fontan. LBW and prematurity should not be contraindications to early surgical palliation.

Aorta↗