Bidirectional Superior Cavopulmonary Connection Research Articles

Corrected Transposition: Anatomic Repair Using the Hemi-Mustard Atrial Baffle and Bidirectional Superior Cavopulmonary Connection.

Anatomic repair for congenitally corrected transposition requires thoughtful surgical planning at both initial (neonatal or late) presentation, and during definitive repair. An algorithmic approach to the overall management of this lesion, with its many associated intracardiac anomalies, is presented. Modified atrial switch with bidirectional superior cavopulmonary connection is commonly utilized and demonstrates favorable results through a 20-year experience. Herein, technical considerations learned during the implementation of this strategy are described and emphasize the concept, in selected cases, of native pulmonary root preservation by translocation as an adjunct that is uniquely suited by adopting this approach.

Prior Innominate Vein Occlusion Does Not Preclude Successful Bidirectional Superior Cavopulmonary Connection

Low superior vena cava (SVC) blood flow has recently been identified as a marker for bidirectional superior cavopulmonary connection (SCPC) failure and death. Prior innominate vein occlusion is considered a significant anatomic risk factor for SCPC failure. We therefore evaluated the outcomes of infants who underwent SCPC with known upper-body venous obstruction. Between February 1995 and June 2014, SCPC was carried out in 8 patients who had either a single SVC with known prior occlusion of the innominate vein (n = 6) or bilateral SVCs without a bridging vein with occlusion of one SVC (n = 2). The cause of the occlusion was an indwelling catheter in 5 patients. These patients were compared with 8 patients with normal upper-body venous drainage who underwent SCPC. Patients were evaluated for preoperative risk factors (including SVC size, pulmonary artery size, Nakata index, pulmonary vascular resistance), operative factors, and clinical outcomes to determine the impact of prior upper-body venous occlusion on SCPC failure or death. There were no significant differences in preoperative risk factors between the two groups, except for a significantly lower Nakata index in the study group with a trend toward smaller pulmonary artery branch size. There were no SCPC takedowns or mortalities. There was no significant difference in postoperative length of stay (median of 7 days [range, 5 to 32 days] versus 5 days [range, 4 to 32 days]; p = 0.17. Study patients had a lower mean systemic oxygen saturation at discharge, 81% versus 85% (p = 0.05). In the study group, at a median follow-up of 42 months, 3 patients underwent successful Fontan completion and 5 are still awaiting Fontan completion. Although patients with prior upper-body venous obstruction may have lower systemic oxygen saturations at hospital discharge, they do not demonstrate an increased SCPC failure or mortality rate. Innominate vein occlusion or its equivalent in patients with bilateral SVCs should not preclude the performance of SCPC. Physiologic rather than anatomic evaluation of preoperative systemic venous return may be more useful to predict outcome after SCPC.

The effects of different ventilator modes on cerebral tissue oxygen saturation in patients with bidirectional superior cavopulmonary connection

We used near-infrared spectroscopy to document changes in cerebral tissue oxygen saturation (SctO2) in response to ventilation mode alterations after bidirectional Glenn (BDG; superior cavopulmonary connection) procedure. We also determined whether spontaneous ventilation have a beneficial effect on hemodynamic status, lactate and SctO2 when compared with other ventilation modes. 20 consecutive patients undergoing BDG were included. We measured SctO 2 during three ventilator modes (intermittent positive-pressure ventilation [IPPV]; synchronized intermittent mandatory ventilation [SIMV]; and continuous positive airway pressure + pressure support ventilation [CPAP + PSV]). We, also, measured mean airway pressure (AWP), arterial blood gases, lactate and systolic arterial pressures (SAP). There was no change in SctO2 in IPPV and SIMV modes; the SctO2 measured during CPAP + PSV and after extubation increased significantly (60.5 ± 11, 61 ± 10, 65 ± 10, 66 ± 11 respectively) (P < 0.05). The differences in the SAP measured during IPPV and SIMV modes was insignificant; the SAP increased significantly during CPAP + PSV mode and after extubation compared with IPPV and SIMV (109 ± 11, 110 ± 12, 95 ± 17, 99 ± 13 mmHg, respectively) (P < 0.05). Mean AWP did not change during IPPV and SIMV modes, mean AWP decreased significantly during CPAP + PSV mode (14 ± 4, 14 ± 3, 10 ± 1 mmHg, respectively) (P < 0.01). The SctO2 was higher during CPAP + PSV ventilation and after extubation compared to IPPV and SIMV modes of ventilation. The mean AWP was lower during CPAP + PSV ventilation compared to IPPV and SIMV modes of ventilation.

Persistent Left Superior Vena Cava Remnant Causing Cyanosis in a Post-Fontan Patient

We report the successful surgical closure of a persistent left superior vena cava remnant draining into the pulmonary venous circulation causing cyanosis in a post-Fontan patient who had previously undergone Damus-Kaye-Stansel and bidirectional superior cavopulmonary connection followed by a transcatheter coil occlusion of his persistent left superior vena cava.

Systemic to pulmonary collateral blood flow influences early outcomes following the total cavopulmonary connection

BackgroundSystemic to pulmonary collaterals (SPCs) represent an additional and unpredictable source of pulmonary blood flow in patients with single ventricle physiology following bidirectional superior cavopulmonary connection (BCPC). Understanding their influence...

Hybrid Procedure for Obstructive Neonatal Left Ventricular Tumors

We report the use of the hybrid procedure (bilateral pulmonary artery banding, ductal stenting followed by balloon atrial septostomy) in the first week of life for the treatment of two neonates with large left ventricular fibromas resulting in univentricular physiology. At 6 months of age, second-stage palliation was accomplished and the 2 patients are growing well with normal developmental milestones and no atrial or ventricular ectopy at 30 months. Hybrid strategy offers a less invasive, initial intervention and the options of typical second-stage univentricular palliation, conversion to biventricular physiology in cases of tumor regression, planned surgical resection, or transplantation.

Changes in cerebral saturation profile in response to mechanical ventilation alterations in infants with bidirectional superior cavopulmonary connection*

To document cerebral saturation in response to alterations in mechanical ventilation in infants with bidirectional superior cavopulmonary connection. Prospective study. Pediatric cardiovascular intensive care unit. Children with functional single ventricle who have undergone bidirectional superior cavopulmonary connection. We measured cerebral oxygenation using near-infrared spectroscopy in response to three ventilator interventions (change 50% from baseline): a) hyperventilation with increased tidal volume; b) hyperventilation with increased respiratory rate; and c) hypoventilation by decreased respiratory rate. Physiologic variables documented were cerebral oxygenation index (rSO2i), arterial pH, and PCO2. Ten patients (eight males and two females) underwent placement of bidirectional superior cavopulmonary connection. There were no mortalities. The mean age was months 8.6 (+/-2.1) months. Hyperventilation (tidal volume increase) caused an increase in pH from 7.35 to 7.42 (p = .001), a decreased PCO2 from a baseline 45.9 to 33.9 mm Hg. (p = .002), a decrease in rSO2i from 64.4 to 52.0 (p < .001), and a decreased Po2 from 52.8 to 46.9 mm Hg (p = .008). Hyperventilation (respiratory rate increase) caused increased pH from 7.35 to 7.39 (p = .002), decreased PCO2 from a baseline 41 to 37 mm Hg. (p = .021), decreased rSO2i from 65.9 to 56.7 (p = .007), and decreased PO2 from 54.9 to 48.9 mm Hg (p = .006). Hypoventilation (respiratory rate decrease) did not change pH did not change from baseline 7.35. The PCO2 increased from 40.8 to 42, and the rSO2i increased from 64.0 to 68.6 (p = .004). Hyperventilation can potentially cause a decrease in cerebral oxygenation and should be avoided in children with bidirectional superior cavopulmonary connection. Normoventilation and mild respiratory acidosis, however, preserve cerebral oxygenation in these patients.

Optimal timing of the second stage of palliation for hypoplastic left heart syndrome facilitated through home monitoring, and the results of early cavopulmonary anastomosis

For children with hypoplastic left heart syndrome, contemporary management over three stages includes a window of high risk for sudden death between the initial stage of palliation, the Norwood operation itself, and the second stage, creation of the bidirectional superior cavopulmonary connection. The risk is highest at a time when patients have been discharged from the hospital to grow and prepare for the second stage,1–4and has persisted despite the remarkable improvements in immediate postoperative and hospital survival after the initial surgery.5,6Potential contributing factors to the increased vulnerability to sudden death between the stages include the limited circulatory reserve inherent in the parallel circulations supported by a functionally univentricular heart, the reliance on a prosthetic shunt which is susceptible to thrombosis, and congenital or acquired anatomical cardiovascular abnormalities such as aortic atresia, residual obstruction in the aortic arch, tricuspid valvar insufficiency, or right ventricular dysfunction.7–12

Home surveillance program prevents interstage mortality after the Norwood procedure

Objective To determine whether early identification of physiologic variances associated with interstage death would reduce mortality, we developed a home surveillance program. Methods Patients discharged before initiation of home surveillance (group A, n = 63) were compared with patients discharged with an infant scale and pulse oximeter (group B, n = 24). Parents maintained a daily log of weight and arterial oxygen saturation according to pulse oximetry and were instructed to contact their physician in case of an arterial oxygen saturation less than 70% according to pulse oximetry, an acute weight loss of more than 30 g in 24 hours, or failure to gain at least 20 g during a 3-day period. Results Interstage mortality among infants surviving to discharge was 15.8% (n = 9/57) in group A and 0% (n = 0/24) in group B ( P = .039). Surveillance criteria were breached for 13 of 24 group B patients: 12 patients with decreased arterial oxygen saturation according to pulse oximetry with or without poor weight gain and 1 patient with poor weight gain alone. These 13 patients underwent bidirectional superior cavopulmonary connection (stage 2 palliation) at an earlier age, 3.7 ± 1.1 months of age versus 5.2 ± 2.0 months for patients with an uncomplicated interstage course ( P = .028). A growth curve was generated and showed reduced growth velocity between 4 and 5 months of age, with a plateau in growth beyond 5 months of age. Conclusion Daily home surveillance of arterial oxygen saturation according to pulse oximetry and weight selected patients at increased risk of interstage death, permitting timely intervention, primarily with early stage 2 palliation, and was associated with improved interstage survival. Diminished growth identified 4 to 5 months after the Norwood procedure brings into question the value of delaying stage 2 palliation beyond 5 months of age.

Hypoventilation improves oxygenation after bidirectional superior cavopulmonary connection

Objective Bidirectional superior cavopulmonary connection may be complicated by systemic hypoxemia. Previous work has shown that hyperventilation worsens systemic oxygenation in patients after bidirectional superior cavopulmonary connection. The likely mechanism is that hyperventilation-induced hypocarbia decreases cerebral, superior vena caval, and pulmonary blood flow. The aim of the current study was to determine whether the converse approach, hypoventilation, improves oxygenation after bidirectional superior cavopulmonary connection. Methods This is a prospective, patient-controlled study of 15 patients (median age 8.0 months, range 4.7-15.5) who underwent bidirectional superior cavopulmonary connection. Patients were studied in the intensive care unit, within 8 hours of surgery, while sedated, paralyzed, and mechanically ventilated. To avoid acidosis during hypoventilation, sodium bicarbonate was administered before hypoventilation. Cerebral blood flow velocity was measured by transcranial Doppler sonography of the middle cerebral artery. Results Hypoventilation following administration of sodium bicarbonate (pH-buffered hypoventilation) produced hypercarbia (mean P co 2 = 58 mm Hg versus 42 mm Hg at baseline). During hypoventilation, there were significant increases in both mean arterial P o 2 (from 50 mm Hg at baseline to 61 mm Hg; P < .05) and mean systemic oxygen saturation (from 86% at baseline to 90%; P < .05). These increases occurred despite accompanying, small increases in pulmonary artery pressure and transpulmonary gradient. Hypoventilation also produced an increase in mean cerebral blood flow velocity (from 37 cm/s at baseline to 55 cm/s; P < .05) and a decrease in the arteriovenous oxygen saturation difference across the upper body (from 33% at baseline to 23%; P < .05), consistent with increased cerebral blood flow. Conclusions This study demonstrates that hypoventilation improves systemic oxygenation in patients after bidirectional superior cavopulmonary connection. The likely mechanism for this effect is that hypoventilation-induced hypercarbia decreases cerebral vascular resistance, thus increasing cerebral, superior vena caval, and pulmonary blood flow. Hypoventilation may be a useful clinical strategy in patients who are hypoxemic in the early postoperative period after bidirectional superior cavopulmonary connection.

Sodium nitroprusside infusion after bidirectional superior cavopulmonary connection: preserved cerebral blood flow velocity and systemic oxygenation

Objective Systemic hypertension is common in patients after bidirectional superior cavopulmonary connection. It can be treated with a vasodilator, such as sodium nitroprusside. However, it is possible that systemic hypertension is necessary to maintain cerebral blood flow in the face of cerebral venous hypertension. Furthermore, bidirectional superior cavopulmonary connection places the cerebral and pulmonary vascular beds in series. Thus treatment of systemic hypertension by lowering blood pressure might decrease cerebral blood flow, pulmonary blood flow, and systemic oxygen levels. The aim of the current study was to determine the effects of sodium nitroprusside on cerebral blood flow velocity and systemic oxygenation in patients after bidirectional superior cavopulmonary connection. Methods This is a prospective patient-controlled study of 9 patients (median age, 7 months; age range, 4 to 12 months) undergoing bidirectional superior cavopulmonary connection. Patients were studied in the intensive care unit within 6 hours of surgical intervention while sedated, paralyzed, and mechanically ventilated. Sodium nitroprusside was infused to achieve a decrease in mean systemic blood pressure of approximately 20%. Cerebral blood flow velocity was measured by means of transcranial Doppler ultrasonography of the middle cerebral artery. Results During sodium nitroprusside infusion, mean systemic blood pressure decreased (from 69 ± 6 mm Hg at baseline to 58 ± 6 mm Hg, P < .05). However, there was no accompanying change in 2 indicators of cerebral blood flow: blood flow velocity in the middle cerebral artery and arteriovenous oxygen saturation difference across the upper body. Both arterial P o 2 and systemic oxygen saturation were also preserved during sodium nitroprusside infusion. Conclusions Sodium nitroprusside decreases systemic blood pressure in patients after bidirectional superior cavopulmonary connection. This decrease occurs without accompanying changes in cerebral blood flow velocity or systemic oxygen levels. These findings suggest that cerebral and pulmonary blood flows are preserved during sodium nitroprusside infusion. Sodium nitroprusside appears to be an appropriate agent for the treatment of systemic hypertension after bidirectional superior cavopulmonary connection.

The infant with single ventricle and excessive pulmonary blood flow: results of a strategy of pulmonary artery division and shunt

Background. The infant with a single ventricle and excessive pulmonary blood flow requires early protection of the pulmonary vascular bed to insure suitability for a subsequent Fontan procedure. The traditional approach, pulmonary artery banding, has had disappointing results. We have pursued an alternate strategy: division of the pulmonary artery, and placement of a systemic-to-pulmonary artery shunt. Potential sites of systemic outflow tract obstruction are simultaneously bypassed, by either a Damus-Kaye-Stansel, or modified Norwood procedure. Methods. From January 1996 to June 2001, 22 infants were treated by this strategy. Patients with hypoplastic left heart syndrome were excluded. Median age was 18 days (range 2 days to 6 months). In addition to pulmonary artery division and shunt, 3 of 22 patients underwent a Damus-Kaye-Stansel procedure, and 13 of 22 patients underwent a modified Norwood procedure. Results. There were no operative deaths, and one late death. Actuarial survival beyond 30 months was 90%. At follow-up catheterization in 22 patients, median transpulmonary gradient was 7 mmHg (range 4 to 18), and median pulmonary vascular resistance 1.9 Wood units (range 0.9 to 3.3). Twenty-one patients have undergone a subsequent bidirectional superior cavopulmonary connection, and 6 a Fontan procedure, with no deaths. No patient developed subaortic stenosis, or aortic arch obstruction. Neoaortic insufficiency was none or trivial in 12 patients, mild in 3, and moderate in 1. Conclusions. In patients with a functional single ventricle and excessive pulmonary flow, a strategy of pulmonary artery division and shunt, along with prophylactic bypass of systemic outflow obstruction, carries low operative and midterm mortality. It provides consistent protection of the pulmonary vascular bed, avoids subaortic stenosis and aortic arch obstruction, minimizes neoaortic insufficiency, and ensures suitability for progression along a Fontan pathway. These results provide a comparison for alternate strategies, including pulmonary artery banding.

Allograft Root on Closed Pulmonary Valve for Subaortic Obstruction in Double-Inlet Left Ventricle With Transposition of the Great Arteries

Background. Until recently closure of the pulmonary valve during staged Fontan-type palliation in the setting of double-inlet left ventricle with an unrestrictive or adequately enlarged ventricular septal defect and transposition of the great arteries with the aorta on a left-sided outflow chamber was regarded as an appropriate part of surgical treatment. Lately, however, an increased incidence of subsequent subaortic obstruction has been described in this regard.Methods. Allograft root placement on the previously closed pulmonary orifice in combination with a modified Damus-Kaye-Stansel procedure is described to create an unobstructed outflow from the main ventricle to the systemic circulation. This procedure was done in 3 patients. One root placement was combined with the construction of the bidirectional superior cavopulmonary connection, one was done as an intermediate step before completion of the cavopulmonary connection, and one was combined with completion of total cavopulmonary connection.Results. Immediate relief of the subaortic obstruction was achieved in all 3 patients. Ventricular hypertrophy, echocardiographically assessed by diastolic posterior wall thickness, regressed to normal in all 3 within 6 to 12 months.Conclusions. Allograft root placement on the reopened pulmonary orifice in double-inlet left ventricle with a ventricular septal defect and transposition of the great arteries appears technically feasible and functionally adequate on short-term follow-up. This procedure should result in regression of ventricular hypertrophy to allow eligibility for a Fontan-type palliation again. To what extent possible failure of the allograft increases the risk of an adverse outcome of this palliation may be a matter of concern.(Ann Thorac Surg 1997;63:425–8)