Angiographic tool to detect pulmonary arteriovenous malformations in single ventricle physiology.

OBJECTIVE: Individuals with single ventricle physiology who are palliated with superior cavopulmonary anastomosis (Glenn surgery) may develop pulmonary arteriovenous malformations. The traditional tools for pulmonary arteriovenous malformation diagnosis are often of limited diagnostic utility in this patient population. We sought to measure the pulmonary capillary transit time to determine its value as a tool to identify pulmonary arteriovenous malformations in patients with single ventricle physiology. METHODS: We defined the angiographic pulmonary capillary transit time as the number of cardiac cycles required for transit of contrast from the distal pulmonary arteries to the pulmonary veins. Patients were retrospectively recruited from a single quaternary North American paediatric centre, and angiographic and clinical data were reviewed. Pulmonary capillary transit time was calculated in 20 control patients and compared to 20 single ventricle patients at the pre-Glenn, Glenn, and Fontan surgical stages (which were compared with a linear-mixed model). Correlation (Pearson) between pulmonary capillary transit time and haemodynamic and injection parameters was assessed using angiograms from 84 Glenn patients. Five independent observers calculated pulmonary capillary transit time to measure reproducibility (intraclass correlation coefficient). RESULTS: Mean pulmonary capillary transit time was 3.3 cardiac cycles in the control population, and 3.5, 2.4, and 3.5 in the pre-Glenn, Glenn, and Fontan stages, respectively. Pulmonary capillary transit time in the Glenn population did not correlate with injection conditions. Intraclass correlation coefficient was 0.87. CONCLUSIONS: Pulmonary angiography can be used to calculate the pulmonary capillary transit time, which is reproducible between observers. Pulmonary capillary transit time accelerates in the Glenn stage, correlating with absence of direct hepatopulmonary venous flow.

Analysis of inflammatory cytokines in the chest tube drainage of post-operative superior cavopulmonary connection patients.

INTRODUCTION: Prolonged pleural effusions are common post Fontan operation and are associated with morbidity. Fontan pleural effusions have elevated proinflammatory cytokines. Little is known about the chest tube drainage after a superior cavopulmonary connection. We examined the chest tube drainage and the inflammatory profiles in post-operative superior cavopulmonary connection patients. METHODS: This prospective cohort study enrolled 25 patients undergoing superior cavopulmonary connection and 10 age-similar controls. Data are also compared to 25 previously published Fontan patients and their 15 age-similar controls. Chest tube samples were analysed with a 17-cytokine BioPlex Assay. Descriptive statistics and univariate comparisons were made between groups. RESULTS: Duration of chest tube drainage was significantly shorter in superior cavopulmonary connection patients (median 4 days, [interquartile range 3-5 days]) versus Fontan patients (10 days, [7-11 days], p < 0.0001). Cytokine concentrations were higher on post-operative day 1 in superior cavopulmonary connection patients versus Fontan patients (all p ≤ 0.01), however levels were comparable to age-similar controls. While proinflammatory IL 8, MIP-1ß, and TNF-α concentrations increased in chest tube drainage of Fontan patients from post-operative day 1 to last chest tube day (all p < 0.0001), there was no change in these biomarkers in superior cavopulmonary connection patients, their controls, or Fontan controls. CONCLUSIONS: Our study demonstrates that after superior cavopulmonary connection, proinflammatory cytokines in the chest tube drainage remain similar to biventricular controls of both age groups, unlike the significant rise over time observed in Fontan patients. Inflammation within the chest tube drainage is likely not innate to single ventricle patients.

Surgical Timing and Outcomes of Unilateral Versus Bilateral Superior Cavopulmonary Anastomosis: An Analysis of Pediatric Heart Network Public Databases.

Requiring bilateral superior cavopulmonary anastomosis (bSCPA) instead of unilateral superior cavopulmonary anastomosis (uSCPA) could influence surgical timing and outcomes. We compared surgical timing and outcomes for patients who underwent uSCPA to those who underwent bSCPA through use of the Pediatric Heart Network's public datasets for the Infant Single Ventricle trial and Single Ventricle Reconstruction trial. There was no statistically significant difference in median age at SCPA (158 vs. 150 days, p = 0.68), hospital length of stay (LOS) (7 vs. 7 days, p = 0.74), intensive care unit (ICU) LOS (4 vs. 5 days, p = 0.53), time requiring ventilator support (2 vs. 2 days, p = 0.51), or oxygen saturation at discharge (82 vs. 81%, p = 0.22) between the uSCPA and bSCPA groups, respectively. However, sub-analysis comparing only those who underwent early SCPA, at < 120 days of age, revealed significantly longer hospital LOS (8 vs. 13 days, p = 0.04), ICU LOS (5 vs. 11 days, p = 0.01), and time requiring ventilator support (2 vs. 4 days, p = 0.03) for the early bSCPA group when compared to the early uSCPA group. A multivariable logistic regression revealed bSCPA to be the only significant predictor of prolonged hospital LOS for patients who underwent early SCPA (odds ratio 4.1, 95% CI 1.2-14.2). Overall, there was no difference in surgical timing or outcome measures between uSCPA and bSCPA. However, early bSCPA, performed at < 120 days, had worse outcome measures than early uSCPA. Delaying elective bSCPA until at least 120 days of age could minimize morbidity in infants with bilateral superior venae cavae.

Impact of the superior cavopulmonary anastomosis on cerebral oxygenation.

BACKGROUND: Patients with univentricular heart disease may undergo a superior cavopulmonary anastomosis, an operative intervention that raises cerebral venous pressure and impedance to cerebral venous return. The ability of infantile cerebral autoregulation to compensate for this is not well understood. MATERIALS AND METHODS: We identified all patients undergoing a superior cavopulmonary anastomosis (cases) and compared metrics of cerebral oxygenation upon admission to the ICU with patients following repair of tetralogy of Fallot or arterial switch operation (controls). The primary endpoint was cerebral venous oxyhaemoglobin saturation measured from an internal jugular venous catheter. Other predictor variables included case-control assignment, age, weight, sex, ischemic times, arterial oxyhaemoglobin saturation, mean arterial blood pressure, and superior caval pressure. RESULTS: A total of 151 cases and 350 controls were identified. The first post-operative cerebral venous oxyhaemoglobin saturation was significantly lower following superior cavopulmonary anastomosis than in controls (44 ± 12 versus 59 ± 15%, p < 0.001), as was arterial oxyhaemoglobin saturation (81 ± 9 versus 98 ± 5%, p < 0.001). Cerebral venous oxyhaemoglobin saturation correlated poorly with superior caval pressure in both groups. When estimated by linear mixed effects model, arterial oxyhaemoglobin saturation was the primary determinant of central venous oxyhaemoglobin saturation in both groups (ß = 0.79, p = 3 × 10-14); for every 1% point increase in arterial oxyhaemoglobin saturation, there was a 0.79% point increase in venous oxyhaemoglobin saturation. In this model, no other predictors were significant, including superior caval pressure and case-control assignment. CONCLUSION: Cerebral autoregulation appears to remain intact despite acute imposition of cerebral venous hypertension following superior cavopulmonary anastomosis. Following superior cavopulmonary anastomosis, cerebral venous oxyhaemoglobin saturation is primarily determined by arterial oxyhaemoglobin saturation.

Transcatheter stenting of superior vena cava obstruction after pediatric heart transplantation: A single-center experience assessing risk factors and outcomes.

Transcatheter stent implantation for SVC obstruction following OHT has been well described, particularly in pediatric patients. This study describes a large single-center pediatric heart transplant experience that investigates the risk factors for SVC stenosis requiring stent implantation and its associated outcomes. All pediatric OHTs between January 1, 2000, and December 12, 2016, were examined for risk factors. Twelve of 349 (3.4%) OHTs required SVC stent implantation. Patients who required stents were younger (2.5 years vs 10.0 years, P = 0.0097), weighed less (8.6 kg vs 26.0 kg, P = 0.0024), and were more likely to have had CHD (83% vs 32%, P = 0.001) or previous SCPA (58% vs 18%, P = 0.002). Bicaval anastomosis was not associated with subsequent SVC stent implantation. Symptoms included SVC syndrome and chylous effusions. All 12 patients had evidence of significant SVC obstruction by both echocardiographic Doppler interrogation and transcatheter angiography. There were no acute procedural complications; however, reinterventions were common (four of 12 patients) and occurred at a mean of 5.7 ± 3.6 months poststent implantation. In conclusion, transcatheter SVC stent implantation is safe and effective after OHT. There were significant associations between SVC stent implantation and younger age, smaller weight, CHD, and history of SCPA, but not with bicaval anastomosis or donor-recipient weight ratio.

Mechanical Ventilation After Bidirectional Superior Cavopulmonary Anastomosis for Single-Ventricle Physiology: A Comparison of Pressure Support Ventilation and Neurally Adjusted Ventilatory Assist.

We evaluated the effects of different respiratory assist modes on cerebral blood flow (CBF) and arterial oxygenation in single-ventricle patients after bidirectional superior cavopulmonary anastomosis (BCPA). We hypothesized that preserved auto-regulation of respiration during neurally adjusted ventilatory assist (NAVA) may have potential advantages for CBF and pulmonary blood flow regulation after the BCPA procedure. We enrolled 23 patients scheduled for BCPA, who underwent pressure-controlled ventilation (PCV), pressure support ventilation (PSV), and NAVA at two assist levels for all modes in a randomized order. PCV targeting large V T (15 mL × kg(-1)) resulted in lower CBF and oxygenation compared to targeting low V T (10 mL × kg(-1)). During PSV and NAVA, ventilation assist levels were titrated to reduce EAdi from baseline by 75 % (high assist) and 50 % (low assist). High assist levels during PSV (PSVhigh) were associated with lower PaCO2, PaO2, and O2SAT, lower CBF, and higher pulsatility index compared with those during NAVAhigh. There were no differences in parameters when using low assist levels, except for slightly greater oxygenation in the NAVAlow group. Modifying assist levels during NAVA did not influence hemodynamics, cerebral perfusion, or gas exchange. Targeting the larger V T during PCV resulted in hyperventilation, did not improve oxygenation, and was accompanied by reduced CBF. Similarly, high assist levels during PSV led to mild hyperventilation, resulting in reduced CBF. NAVA's results were independent of the assist level chosen, causing normalized PaCO2, improved oxygenation, and better CBF than did any other mode, with the exception of PSV at low assist levels.

Angiographic Tool to Detect Pulmonary Arteriovenous Malformations in Single Ventricle Physiology.

Background: Individuals with single ventricle physiology who are palliated with superior cavopulmonary anastomosis (Glenn surgery) may develop pulmonary arteriovenous malformations (PAVMs). The traditional tools for PAVM diagnosis are often of limited diagnostic utility in this patient population. We sought to measure the pulmonary capillary transit time (PCTT) to determine its value as a tool to identify PAVMs in patients with single ventricle physiology. Methods: We defined the angiographic PCTT as the number of cardiac cycles required for transit of contrast from the distal pulmonary arteries to the pulmonary veins. Patients were retrospectively recruited from a single quaternary North American pediatric center, and angiographic and clinical data was reviewed. PCTT was calculated in 20 control patients and compared to 20 single ventricle patients at the pre-Glenn, Glenn, and Fontan surgical stages (which were compared with a linear-mixed model). Correlation (Pearson) between PCTT and hemodynamic and injection parameters was assessed using 84 Glenn angiograms. Five independent observers calculated PCTT to measure reproducibility (intra-class correlation coefficient). Results: Mean PCTT was 3.3 cardiac cycles in the control population, and 3.5, 2.4, and 3.5 in the pre-Glenn, Glenn, and Fontan stages, respectively. PCTT in the Glenn population did not correlate with injection conditions. Intraclass correlation coefficient was 0.87. Conclusions: Pulmonary angiography can be used to calculate the pulmonary capillary transit time, which is reproducible between observers. PCTT accelerates in the Glenn stage, correlating with absence of direct hepatopulmonary venous flow.

Left pulmonary artery reconstruction using cryopreserved pulmonary homograft.

In patients with univentricular heart, the Fontan procedure is the final palliation. This is usually staged. A systemic-to-pulmonary artery shunt is performed in the presence of episodes of cyanotic spells in the neonatal period or in some patients in infancy; a bidirectional superior cardiopulmonary anastomosis is preferred early in life. This is followed by the final Fontan palliation on an elective basis later. For an effective bidirectional superior cavopulmonary anastomosis and Fontan palliation, good-sized confluent pulmonary arteries (PAs) are mandatory in addition to favorable hemodynamic data. Patients with discontinuous PAs that are small in size present a surgical challenge at initial palliation as the one described in this report.

Coronary Sinus Ostial Obstruction in Single-Ventricle Congenital Heart Disease: Two Patients With Different Outcomes.

Coronary sinus ostial obstruction is an exceedingly rare anomaly that is particularly important to diagnose in patients with single-ventricle heart disease before surgical palliation. We present 2 cases, an infant and an adult, diagnosed with coronary sinus ostial obstruction, with different clinical outcomes due to timing of diagnosis. (Level of Difficulty: Intermediate.).

Incidence and Management of Thrombotic and Thromboembolic Complications Following the Superior Cavopulmonary Anastomosis Procedure: A Literature Review.

The objective of this literature review was to estimate the incidence of thrombosis and thromboembolism associated with the superior cavopulmonary anastomosis (SCPA) procedure and its variants and to examine current thromboprophylaxis regimens utilized. MEDLINE and EMBASE were searched from inception to August 2017 for all prospective and retrospective cohort studies explicitly reporting incidence of thrombosis, thromboembolism, or shunt occlusion in neonates, infants, and children undergoing 1 or more variants of the SCPA procedure. End points included thrombotic events and thromboembolic events (strokes and pulmonary embolisms) as primary outcomes, and overall mortality as a secondary outcome, at the last available follow-up time point. Of 1303 unique references identified, 13 cohort studies were deemed eligible. Reported incidence of thrombosis and thromboembolic events ranged from 0% to 28.0% and from 0% to 12.5%, respectively. Reported incidence of major bleeding events ranged from 0% to 2.9%. Reported overall mortality ranged from 2.5% to 50.5% across studies. Thromboprophylaxis protocols varied across institutions and studies, most commonly involving unfractionated heparin (UFH), warfarin, enoxaparin, acetylsalicylic acid (ASA), or combinations of ASA and warfarin, ASA and low-molecular-weight heparin (LMWH), UFH and LMWH, and UFH and ASA; several studies did not specify a protocol. Due to substantial variability in reported event rates, no clear correlation was identified between prophylaxis protocols and postoperative thrombotic complications. Despite guidance recommending postoperative UFH as standard practice, thromboprophylaxis protocols varied across institutions and studies. More robust trials evaluating different thromboprophylaxis regimens for the management of these patients are warranted.

Staged Surgical Palliation for HLHS in a Girl with Severe Factor X Deficiency.

Background Factor X deficiency (also known as Stuart-Prower factor deficiency) is an autosomal recessive extremely rare hereditary hematologic disorder, affecting around 1:1,000,000 of the general population. Case Presentation This case report describes a patient with hypoplastic left heart syndrome and severe factor X deficiency, who underwent staged surgical palliation. From stage 1 Norwood palliation, through superior cavopulmonary anastomosis and ending with total cavopulmonary connection with satisfactory hemostasis and no significant perioperative bleeding complication. Conclusion The need to maintain hemostasis while aiming to prevent intracardiac thrombosis requires multidisciplinary team approach including hematologist, cardiac surgeon, pediatric cardiac intensivist, and anesthesiologist along with meticulous hemostasis during surgery and careful monitoring of coagulation profile in the postoperative period.

Quantification of ventricular unloading by 3D echocardiography in single ventricle of left ventricular morphology following superior cavo-pulmonary anastomosis and Fontan completion - a feasibility study.

BACKGROUND: Three-dimensional echocardiography. (3DE) is comparable to cardiac magnetic resonance imaging for estimating ventricular volume in congenital heart diseases. However, there are limited data on estimation of ventricular volumes by 3DE in univentricular heart and change in ventricular volumes after surgical creation of cavopulmonary connection. We sought to quantify the unloading of the single ventricle of left ventricular. (LV) morphology by 3DE after superior cavopulmonary anastomosis. (SCPA) or Fontan operation over a period of 3 months and thereby derive a preliminary 3DE data set on this patient subset. PATIENTS AND METHODS: Eighteen patients with functional single ventricle of LV morphology, who underwent SCPA or completion of Fontan circulation, were included in the study. Volume of the ventricle was estimated by 3DE before surgery and after surgery. (in the early postoperative phase and 3 months after surgery), and indexed end-diastolic volume. (EDV), end-systolic volume. (ESV), and ejection fraction. (EF) were derived. RESULTS: Twelve patients underwent SCPA and six patients underwent staged completion of Fontan circulation. Before surgery, EDV was similar in both groups. There was a significant fall in EDV immediately after SCPA (from 48.3 ± 14.9 ml/m2 to 39.5 ± 12.3 ml/m2). However, EDV increased at 3 months' follow-up to 41.3 ± 10.5 ml/m2. There was no significant fall in EDV immediately after Fontan operation (47.2 ± 10.1 ml/m2-46.6 ± 14.2 ml/m2), but EDV continued to fall at 3 months of follow-up (44.7 ± 10. ml/m2). There was no significant change in ESV in either group, but EF fell significantly after SCPA. CONCLUSIONS: We provide preliminary information on 3DE volume data of single ventricle of LV morphology and the pattern of unloading after SCPA and Fontan operation. Immediate significant volume unloading occurred after SCPA which tended to catch-up after 3 months, whereas continued fall in ventricular volume with time was noted after Fontan.

The Effect of the Superior Cavopulmonary Anastomosis on Ventricular Remodeling in Infants with Single Ventricle.

BACKGROUND: Infants with single ventricular physiology have volume and pressure overload that adversely affect ventricular mechanics. The impact of superior cavopulmonary anastomosis (SCPA) on single left ventricles versus single right ventricles is not known. METHODS: As part of the Pediatric Heart Network placebo-controlled trial of enalapril in infants with single ventricular physiology, echocardiograms were obtained before SCPA and at 14 months and analyzed in a core laboratory. Retrospective analysis of the following measurements included single ventricular end-diastolic volume (EDV), end-systolic volume (ESV), mass, mass-to-volume ratio (mass/volume), and ejection fraction. Qualitative assessment of atrioventricular valve regurgitation and assessment of diastolic function were also performed. RESULTS: A total of 156 participants underwent echocardiography at both time points. Before SCPA, mean ESV and mass Z scores were elevated (3.4 ± 3.7 and 4.2 ± 2.9, respectively) as were mean EDV and mass/volume Z scores (2.1 ± 2.5 and 2.0 ± 2.9, respectively). EDV, ESV, and mass decreased after SCPA, but mass/volume and the degree of atrioventricular valve regurgitation did not change. Subjects with morphologic left ventricles demonstrated greater reductions in ventricular volumes and mass than those with right ventricles (mean change in Z score: left ventricular [LV] EDV, -1.9 ± 2.1; right ventricular EDV, -0.7 ± 2.5; LV ESV, -2.3 ± 2.9; right ventricular ESV, -0.9 ± 4.6; LV mass, -2.5 ± 2.8; right ventricular mass, -1.3 ± 2.6; P ≤ .03 for all). Approximately one third of patients whose diastolic function could be assessed had abnormalities at each time point. CONCLUSIONS: Decreases in ventricular size and mass occur in patients with single ventricle after SCPA, and the effect is greater in those with LV morphology. The remodeling process resulted in commensurate changes in ventricular mass and volume such that the mass/volume did not change significantly in response to the volume-unloading surgery.

The Hemi-Fontan operation: A critical overview.

The hemi-Fontan (HF) operation is a staging procedure in the journey towards an ultimate Fontan palliation. Although popular in the Western world, it has found limited application in the developing world. In this review we discuss the indications, techniques, merits, and demerits of this procedure along with its present day role in developing world where there is lack of awareness about this operation.