Biomedical subjects

Christian Pizarro

Publications and source records attributed to Christian Pizarro.

12 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↗

PubMed2005

Neonatal repair of tetralogy of Fallot results in improved pulmonary artery development without increased need for reintervention.

OBJECTIVE: Despite a continuous improvement in operative outcome the optimal timing for the repair of tetralogy of Fallot (TOF) remains controversial. The purpose of this study was to evaluate the results following neonatal repair of TOF and the need for reintervention associated with this strategy. METHODS: Retrospective review of 66 consecutive patients with TOF and confluent pulmonary arteries, who underwent repair immediately after diagnosis. Group I (n=46) had a median age of 5 days (1-29) and Group II (n=20) had a median age of 56 days (32-270). A transventricular approach was used in all cases, and 58/66 (88%) patients received a transannular patch. The median follow-up interval was 35 months (1-79). RESULTS: There were three early deaths (4.5%) and no late deaths for an actuarial survival rate of 95.4% at 1 and 5 years. Univariate analysis of patient and procedural variables demonstrated that early mortality was only influenced by associated non-cardiac conditions (P=0.04). At median interval of 9.8 months (3-41), 12 patients required additional intervention. During the follow-up period, a significant increase in Nakata index was observed only among neonates. Freedom from reintervention at 1 month, 1 and 5 years was: 100, 84.2 and 81% in group I and 100, 84, 78.9% in group II. Surgical weight below 2.5 kg (P<0.001), low arterial saturation in the early postoperative period (P=0.04) and small preoperative branch pulmonary artery size (<0.01) were associated with need for reintervention during follow-up. CONCLUSIONS: Elective repair of TOF in neonates with confluent central pulmonary arteries has excellent results in the absence of significant associated non-cardiac conditions. While enhancing the development and growth of the pulmonary arteries, neonatal repair affords a freedom from reintervention no different from patients repaired during infancy. Preoperative weight < 2.5 kg and small left pulmonary artery size are associated with higher incidence reintervention during follow-up.

Age Factors↗

PubMed2005

Off pump palliation for hypoplastic left heart syndrome: surgical approach.

The ongoing effort to improve the outcomes of patients with hypoplastic left heart syndrome and the awareness about their neurologic function has prompted consideration for a palliative strategy that does not subject these neonates to a major intervention associated with the use of cardiopulmonary bypass with or without a period of circulatory arrest. Ductal stenting and pulmonary artery banding, initially reported over a decade ago, offers an alternative form of initial palliation with minimal intervention during the newborn period while keeping all treatment options available. We describe some of the recent experiences and discuss indications, results, and issues to be addressed to further this approach.

Heart Septum↗

PubMed2005

Routine primary repair of tetralogy of Fallot in the neonate.

Uncertainty surrounds both the timing and ideal form of early management of tetralogy of Fallot. Some centers perform early complete repair in all patients regardless of age, symptoms and morphology. Others recommend a two-stage approach involving initial palliation in symptomatic neonates and young infants and those with unfavorable anatomy (anomalous coronary anatomy or hypoplastic pulmonary arteries). Advantages of early anatomic correction include alleviation of cyanosis, normal growth and organ development, removal of stimulus for right ventricular hypertrophy and avoidance of risks associated with initial palliation. With recent advances in anesthetic, operative and postoperative management, routine primary repair of tetralogy of Fallot in the neonate and young infant can be accomplished with excellent early and mid-term results. However, long-term follow-up is necessary to assess the impact of early repair on late right ventricular function, arrhythmias and need for reintervention.

Cardiac Surgical Procedures↗

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↗

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↗

PubMedDate not supplied

Modified CPB circuit for postoperative rescue of high-risk patients following cardiac repair: are we keeping safe?

Extracorporeal membrane oxygenation (ECMO) is commonly used to treat postcardiotomy cardiopulmonary dysfunction in small children. System readiness, need for additional blood products, and exposure to new surfaces are important considerations, particularly when used for resuscitation. We reviewed our experience with a cardiopulmonary bypass (CPB) system modified to provide extended circulatory support system after surgery in patients considered at high risk. When not used in the operating room, the system was recirculated for 24 hours. Before being discarded, blood samples were obtained for activated clotting time, arterial blood gas, and blood cultures from 10 circuits. Between January 2004, and December 2005, 44 patients underwent cardiac repair using this CPB system. ECMO support was initiated in the operating room in 8 patients, and six circuits were used after patient arrival in the intensive care unit. Blood sampling after 24 hours on standby circuits revealed acceptable values for pH, Pao2, hematocrit, ionized calcium, potassium level, and ACT. All blood cultures were negative at 5 days. Survival for patients who received a circuit on standby was 64%.This modified cardiopulmonary circuit can be transformed into a simple, safe, and effective ECMO support system. Deployment of a CPB circuit previously used for cardiac repair has many advantages and maximizes utilization of resources.

Blood Coagulation Tests↗