Does biventricular pacing improve hemodynamics in children undergoing routine congenital heart surgery?

Biventricular (BiV) pacing or cardiac resynchronization therapy (CRT) is an established therapy for heart failure in adults. In children, cardiac dyssynchrony occurs most commonly following repair of congenital heart disease (CHD) where multisite pacing has been shown to improve both hemodynamics and ventricular function. Determining which patient types would specifically benefit has not yet been established. A prospective, repeated measures design was undertaken to evaluate BiV pacing in a cohort of children undergoing biventricular repair for correction of their CHD. Hemodynamics, arterial blood gas, electrocardiographic (ECG), and echocardiographic data were collected. Pacing protocol was undertaken prior to the patient's extubation with 20 min of conventional right ventricular (RV) or BiV pacing, preceded and followed by 10 min of recovery time. Multivariate statistics were used to analyze the data with p values <0.05 considered significant. Twenty-five (14 female) patients underwent surgery at a median (range) age of 5.2 (0.1-37.4) months with no early mortality. The Risk-adjusted classification for Congenital Heart Surgery (RACHS) scores were 2 in 14 patients, 3 in eight patients, and 4 in three patients. None had pre-existing arrhythmias, dyssynchrony, or required pacing pre-operatively. No patient required implantation of a permanent pacemaker post-operatively. The median cardio-pulmonary bypass time was 96 (55-236) min. RV and BiV pacing did not improve cardiac index from baseline (3.23 vs. 3.42 vs. 3.39 L/min/m2; p > 0.05). The QRS duration was not changed with pacing (100 vs. 80 vs. 80 ms; p > 0.05). On echocardiography, the time-to-peak velocity difference between the septal and posterior walls (synchrony) during pacing was similar to baseline and was also not statistically significant. BiV pacing did not improve cardiac output when compared to intrinsic sinus rhythm or RV pacing in this cohort of patients. Our study has shown that BiV pacing is not indicated in children who have undergone routine BiV congenital heart surgery. Further prospective studies are needed to assess the role of multisite pacing in children with ventricular dyssynchrony such as those with single ventricles, those undergoing reoperation or those with high RACHS scores.

Imaging of a carotid aneurysm in two patients following extracorporeal membrane oxygenation therapy.

Following extracorporeal membrane oxygenation (ECMO), two patients subsequently developed carotid aneurysms at the site of cannulation. Given the invasive nature of ECMO, vascular ultrasound and/or computerized tomographic imaging should be considered to rule out cannulation-site complications post-ECMO.

Predicting major adverse events after cardiac surgery in children.

OBJECTIVES: To develop a reliable predictor of major adverse events after pediatric cardiac surgery, with the aim of reducing mortality of cardiac extracorporeal life support through earlier, more accurate patient selection. DESIGN: Prospective observational study. SETTING: Tertiary level pediatric intensive care unit. PATIENTS: Fifty-two children undergoing open heart surgery considered above-average risk based on preoperative assessment. INTERVENTIONS: None; strictly observational study. MEASUREMENTS AND MAIN RESULTS: A wide range of measurements was made at 3, 6, 9, 12, and 24 hrs after surgery, including: oxygen consumption, central venous pressure and oxygen saturation (Scvo2), cardiac output (Fick), heart rate, arterial pressure, arterial lactate, urine output, core-toe temperature gradient, and derived hemodynamic variables. Six children had major adverse events; three needed extracorporeal life support, two died. There were no correlations between routine postoperative measurements (blood pressure, pulse, temperature gradient, central venous pressure) and any measure of cardiac function, and neither group of variables predicted adverse outcomes. Lactate (>8 mmol/L) and Scvo2 (<40%) had high sensitivity (both 73.7%) and specificity (96.3% and 95.4%, respectively), for predicting major adverse event but positive predictive values for both were low (63.6% and 58.3%, respectively). The ratio of the two had better predictive power than the individual values. When the ratio (Scvo2, %)/(lactate, mmol/L) fell below 5, the positive predictive value for major adverse event was 93.8% (sensitivity 78.9%, specificity 90.5%). The effect was present at all postoperative time points. CONCLUSIONS: Lactate and Scvo2 are the only postoperative measurements with predictive power for major adverse events. Forming a ratio of the two (Scvo2/lactate), seems to improve predictive power, presumably by combining their individual predictive strengths. Both measures have excellent specificities but lower sensitivities. Predictive power of single measures is only fair but can be improved, in high risk patients, by monitoring repeated measures over time.

Clipped tube fenestration after extracardiac Fontan allows for simple transcatheter coil occlusion.

BACKGROUND: Expensive devices are increasingly used to close a patent fenestration after a modified Fontan operation. We report our 5-year institutional experience of clipped tube fenestration after extracardiac Fontan operation, which allows for simple transcatheter coil occlusion. METHODS: We retrospectively reviewed 30 children, median age of 4.0 years (range, 2.4 to 8.8 years) who underwent extracardiac Fontan operation between May 1996 and May 2001, and were fenestrated using a 4- to 8-mm diameter clipped tube graft. RESULTS: Ten children had a patent fenestration occluded by transcatheter placement of 15 detachable coils (5- to 8-mm diameter). Aortic oxygen saturations increased on average by 5.5% (2% to 14%) and mean pressures in the Fontan circuit by 2.5 mm Hg (0 to 3 mm Hg). Four had immediate complete occlusion angiographically and 6 had trivial residual shunt, but complete occlusion by echocardiography at follow-up. There have been no immediate complications, late coil embolizations, thromboembolic events, or documented hemolysis within a follow-up after coil implantation of 1.7 years (0.4 to 4.5 years). Spontaneous fenestration closure was documented in 8 patients at cardiac catheterization and 9 patients by echocardiography with consistent improvement in resting transcutaneous oxygen saturation. Two children with a patent fenestration have been considered inappropriate for closure, and there was one early surgical death. There have been no complications related to the tube fenestration modification within a follow-up postoperation of 2.6 years (0.1 to 5.5 years). CONCLUSIONS: Clipped tube fenestration after extracardiac Fontan operation is a useful surgical modification that allows for simple transcatheter coil occlusion.

Na+/H+ exchange inhibition with HOE 642 improves recovery of the injured neonatal rabbit heart.

BACKGROUND: The effects of inhibition of the Na+/H+ exchanger (NHE) on postischemic recovery of the injured neonatal rabbit heart were examined. The NHE may be an important mechanism for reperfusion injury in the neonate heart. The effects of two NHE inhibitors, HOE 642 (HOE) and 5-(N,N-dimethyl)-amiloride (DMA), given during hypothermic cardioplegic arrest, were evaluated. METHODS: Isolated working crystalloid-perfused neonatal rabbit hearts were subjected to 10 min of normothermic ischemia to cause injury before undergoing 4 h of hypothermic (10 degrees C) cardioplegic arrest with a single dose of crystalloid solution (controls, n=21) or with the addition of 0.5 micromol/L HOE (n=24) or 30 micromol/L DMA (n=15). RESULTS: Hearts subjected to HOE had improved recoveries of aortic flow when compared with controls at 15 min and 30 min of reperfusion (35.7+/-1.3 mL/min versus 26.2+/-1.4 mL/min, respectively, at 15 min, P<0.0001; 36.5+/-1.5 mL/min versus 23.6+/-1.6 mL/min, respectively, at 30 min, P<0.0001) and with DMA at 30 min (36.5+/-1.5 mL/min versus 29.9+/-1.9 mL/min, P=0.0214). Cardiac output and systolic pressure were also improved at 30 min in HOE hearts versus controls (P<0.0001). CONCLUSIONS: NHE inhibition with HOE during cardioplegic arrest resulted in improved functional recovery of injured hearts. Further studies in blood-perfused neonatal preparations are warranted.

Outcome following repair of sinus venosus atrial septal defects in children.

The outcome of surgical repair of sinus venosus atrial septal defect was reviewed retrospectively. The operation was performed on 44 children aged 8 to 163 months, between April 1985 and November 1998. Median cardiopulmonary bypass and aortic crossclamp times were 58 minutes (range, 29 to 141 minutes) and 29 minutes (range, 4 to 67 minutes), respectively. Use of blood products decreased from 4.5 units per patient in the first period (1985 to 1989) to 0.6 units in the last period (1995 to 1998). Median intensive care and hospital stays were 2 days (range, 1 to 12 days) and 6 days (range, 4 to 16 days), respectively. There was 1 early death (2.3%). Complications included reexploration for bleeding in 2 patients (4.5%) and for superior vena cava obstruction in 1 (2.3%), and arrhythmias in 3 (6.8%), which required a pacemaker in one. During follow-up of 15 to 176 months, 83.8% of patients were in sinus rhythm. One required angioplasty for superior vena cava stenosis, hemodynamically insignificant residual shunt was found in 3, and mild superior vena cava stenosis in 3. Repair of sinus venosus atrial septal defect carries a low mortality and morbidity, but long-term follow-up is needed to monitor potential sinus node dysfunction and superior vena cava stenosis.

The Contegra conduit: Late outcomes in right ventricular outflow tract reconstruction.

OBJECTIVES: To report the clinical outcomes (early death, late death, and rate of reintervention) and performance of the Contegra conduit as a right ventricle outflow tract implant and to determine the risk factors for early reintervention. METHODS: Forty-nine Contegra conduits were implanted between January 2002 and June 2009. Data collection was retrospective. The mean age and follow-up duration of Contegra recipients was 3.5 ± 4.6 years and 4.2 ± 2.0 years, respectively. RESULTS: There were three deaths (two early, one late), giving a survival rate of 93.9%. The rate of conduit-related reintervention was 19.6% and was most often due to distal conduit stenosis. Age at implantation of <3 months, receipt of a conduit of 12-16 mm diameter, and a diagnosis of truncus arteriosus were each significant contributors to the rate of reintervention. CONCLUSION: The Contegra is a cost-effective and readily available solution. However, there is a limited range of larger calibers, which means that the homograft conduit (>22 mm) remains the first choice of implant in older children. The rates of reintervention are significantly higher with a diagnosis of truncus arteriosus, age at implantation of <3 months, and implantation of conduits sized 12-16 mm.

Assessment of vocal fold mobility before and after cardiothoracic surgery in children.

OBJECTIVES: To assess the incidence of vocal fold immobility (VFI) after cardiothoracic surgery in children and to determine the factors potentially associated with this outcome. METHODS: Flexible laryngoscopy to assess vocal fold mobility was performed before surgery and within 72 hours after extubation in 100 pediatric patients who underwent cardiothoracic procedures. The 2 operating surgeons recorded the surgical technique and their impression of possible injury to the recurrent laryngeal nerve. The presence of laryngeal symptoms, such as stridor, hoarseness, and strength of cry, after extubation was documented. RESULTS: Of 100 children included in this study, 8 had VFI after surgery. Univariate analyses showed that these 8 patients were younger and weighed less than the patients with normal vocal fold movement. Monopolar cautery was used in all patients with VFI. On univariate analysis, factors statistically significantly associated with VFI were circulatory arrest and dissection or ligation of the patent ductus arteriosus, left pulmonary artery, right pulmonary artery, or descending aorta. However, multivariate analyses failed to show these associations. CONCLUSIONS: The incidence of VFI after cardiothoracic surgery in our population of children was 8.0% (8 of 100). Of several factors found to be potentially associated with VFI on univariate analysis, none were significant on multivariate analysis. This may be a result of the few patients with VFI. A larger multicenter prospective study would be needed to definitively identify factors associated with the outcome of VFI.

New surgery for better outcomes: shaping the field of congenital heart disease.

BACKGROUND: The field of congenital heart disease is constantly evolving through better understanding of the disease itself, albeit its history, prevalence, genetics, and follow-up. Concurrently surgical techniques and approaches have been developed, modified, and refined. DATA SOURCES: The impact of interventional pediatric cardiology has been dramatic. The field of catheter-based therapies has exploded with the first pulmonary valve balloon angioplasty in 1982. With evolving stent technology, they are now used in multiple areas, including pulmonary arteries, vena cavae, aortic and arch and descending aorta for coarctation. The hybrid surgery concept involves a multidisciplinary team of interventional cardiologist and surgeon combining catheter-intervention and surgery in the surgical theater such as pulmonary artery stent implantation associated with pulmonary valve replacement. Furthermore, in selected cases, pulmonary valve device implantation is becoming an accepted approach to a surgical problem. RESULTS: Balloon angioplasties, stent implantations, hybrid surgeries and pulmonary valve device implantation are performed with a very low mortality and morbidity. The risks and benefits outweigh the ones associated to surgical procedures. CONCLUSION: With fast developing interventional therapies, the work of pediatric cardiologists and cardiac surgeons is more intertwined than ever in search of better outcomes for the children with congenital heart disease.

Quality-of-life outcomes after surgical correction of pectus excavatum: a comparison of the Ravitch and Nuss procedures.

PURPOSE: The purpose of this study was to compare clinical and health-related quality-of-life (HRQL) outcomes within a group of patients treated for pectus excavatum (PE). METHODS: A retrospective 3-year review of patients undergoing Nuss or Ravitch correction of PE was performed. Health-related quality-of-life assessment was performed using the Child Health Questionnaire (CHQ-CF87) and the 17-item Pectus Excavatum Evaluation Questionnaire, and results were compared between groups and with age-matched CHQ-CF87 normative data. RESULTS: Forty-three patients (39 males; 91%) underwent surgery; 19 (44%) by Nuss procedure. Duration of postoperative opioid analgesia and length of hospital stay (LOS) were significantly longer in Nuss patients. The overall survey response rate was 53%. The groups differed significantly in the CHQ on one item (Change in Health). On the Pectus Excavatum Evaluation Questionnaire, Nuss patients reported being "less bothered" by the appearance of their chest. Compared to Australian age-matched norms, the aggregate PE sample showed better scores for family activity domain and worse scores in mental health, general health perceptions, change in health, bodily pain, and self-esteem. CONCLUSIONS: Patients undergoing surgery for PE by either Nuss or Ravitch procedure have similar clinical and HRQL outcomes, but as a group have poorer HRQL scores than age-matched population norms.

An open and shut case for early VATS treatment of primary spontaneous pneumothorax in children.

BACKGROUND: Treatment of primary spontaneous pneumothorax (SP) involves thoracostomy tube (TT) drainage, with surgery reserved for persistent or recurrent air leaks. We hypothesized that the advent of video-assisted thoracic surgery (VATS) would change indications and outcomes for surgical treatment of SP in our centre. METHODS: We performed a retrospective (1993-2003) review of children treated for SP. Patients with persistent or recurrent air leaks underwent either limited axillary thoracotomy (LAT), 1993-2001, or VATS, 2001-2003. We included the following outcomes: preoperative SP episodes, TT days (that is, patient days with TT in situ, before surgery), length of hospital stay (LOS), narcotic use and freedom from recurrence. We evaluated the predictive value of preoperative CT scans in guiding treatment of the contralateral side. RESULTS: Among 31 patients with 19 ipsilateral or contralateral recurrences (61%), 11 were managed nonoperatively. Twenty-six surgeries (13 LAT, 13 VATS) were performed in 20 patients, with 9 undergoing bilateral procedures (3 LAT, 6 VATS). VATS patients were treated earlier, had a diminished narcotic requirement postoperatively and had a shorter LOS with an equivalent recurrence rate, compared with LAT patients. The absence of contralateral blebs did not predict freedom from SP on the contralateral side in patients undergoing surgery for ipsilateral SP. CONCLUSIONS: Compared with LAT, VATS causes less pain, has a shorter LOS and encourages earlier surgical treatment (including prophylactic, contralateral treatment) of SP in children.

Abdominal aortic injuries associated with chance fractures in pediatric patients.

Injury to the abdominal aortic artery from blunt trauma is an infrequent event with few cases reported in either the adult or the pediatric literature. Injury to the thoracic aorta after blunt abdominal trauma is more common. It has been estimated that 95% to 99% of all aortic disruptions are in the thoracic region. Injury to the abdominal aorta is rarely seen in association with fractures of the lumbar spine secondary to seat belt use in motor vehicle accidents; there are few cases in the literature of these injuries in pediatric patients. Nevertheless, the overall mortality rate of this injury has been reported to be between 18% and 37%. It is therefore important to be aware of the possible association to allow prompt diagnosis and management of multitraumatized patients because extensive injuries to the abdominal viscera may mask aortic dissection and prognosis is significantly improved with early intervention.

Brain, spine, and muscle cytochrome Cu-A redox patterns of change during hypothermic circulatory arrest in swine.

Past near infrared spectroscopy (NIRS) studies have reported different changes in cytochrome C oxidase (Cyt) redox status during similar interventions that cause tissue ischaemia. We investigated whether there were distinctive differences when NIRS signals were obtained simultaneously from different tissues during total circulatory arrest. Forty-two healthy 10 kg commercial swine (Sus scrofa) on cardiopulmonary bypass, each underwent 2 to 8 sequential periods of hypothermic circulatory arrest for 7.5 min. Prior to each arrest, key physiologic variables were adjusted to 1 of 81 combinations of high, normal, or low levels of core temperature, hematocrit, pH, and serum glucose. Each combination was repeated at least twice. Simultaneous NIRS monitoring yielded 202 brain, 191 spine, and 199 muscle Cyt data sets, which were then classified into 13 distinctive patterns of change. The data sets always differed between tissues in the same arrest trial and subject. Typically, brain Cyt rapidly became more reduced at the start of arrest and changed little thereafter, muscle Cyt behaved comparably to brain Cyt but continued to become reduced throughout the arrest, and spine Cyt either did not change status or gradually became more reduced over the course of arrest. The spine pattern's mean rate of change was 12 times slower than those of the brain or muscle. The Cyt patterns of change were classified into 13 groups which were significantly related to core temperature in the brain and spine, and hematocrit in muscle. The respiratory response in mitochondria during systemic circulatory arrest differs between brain, spine and muscle tissues in the same subject.

Temperature, hematocrit, pH, and glucose 4-way ANOVA of cytochrome C oxidase redox status during systemic cold circulatory arrest in swine.

UNLABELLED: Various investigators using near infrared spectroscopy (NIRS) have reported differing patterns of cytochrome C oxidase (cytochrome a,a3) redox status in similar brain oxygenation studies. We investigated whether distinctive differences could be due to combinations of variations in temperature, hematocrit, pH, and glucose. METHODS: Thirty-six healthy 10 kg commercial juvenile swine on cardiopulmonary bypass underwent 2-8 sequential periods of circulatory arrest. Prior to each arrest, key physiological variables were adjusted to match a random selection of one of 81 combinations of high, normal, or low levels of hypothermia, hematocrit, pH, and serum glucose. In the course of the study, the combinations were repeated twice to yield 162 NIRS data sets. RESULTS: The mean rate of change in net oxidized minus reduced cytochrome a,a3 redox status in the brain following 7.5 min of ischemia was 0.49 +/- 0.26 micromol L(-1) min(-1), and, the corresponding mean magnitude of change was -1.23 +/- 0.57 micromol L(-1). The rate of change was influenced by temperature but not by hematocrit, pH, or glucose, either singly or in combination. CONCLUSION: The respiratory response in mitochondria during systemic circulatory arrest is significantly influenced by temperature.

Sternal split approach to the cervicothoracic junction in children.

STUDY DESIGN: We present a descriptive case series outlining the surgical technique and outcome in six patients managed with a combined anterior neck and sternal splitting approach. OBJECTIVES: To describe a surgical approach used in the management of severe cervicothoracic kyphosis and/or scoliosis in pediatric patients. SUMMARY OF BACKGROUND DATA: There are few reports in the literature that address the problem of accessing multileveled spinal deformities around the cervicothoracic junction requiring stabilization in the pediatric population. METHODS: A detailed chart and radiographic review was completed of six consecutive patients managed at our center with a combined anterior neck and sternal splitting approach. The indications, surgical technique, and outcome are reviewed for each case. This technique was employed in 6 pediatric patients, aged 3-15 years, at the authors' institution. Diagnoses included Klippel-Feil Syndrome (2 patients), Proteus Syndrome, Larsen Syndrome, and neurofibromatosis type I (2 patients). All patients had severe cervicothoracic kyphosis requiring surgical instrumentation. This technique allowed surgical access from C5-T6. RESULTS: This approach was invaluable in gaining access to the cervicothoracic junction to address complex spinal deformities in pediatric patients. In one patient, a separate thoracotomy was performed to access the lower thoracic spine. The only significant complication related to the approach was recurrent laryngeal nerve palsy experienced by one patient. This approach allowed stabilization of severe scoliotic and/or kyphotic deformities to impede curve progression. CONCLUSIONS: This approach was invaluable in gaining multileveled access to the cervicothoracic junction to address complex spinal deformities in pediatric patients.

Intraoperative rescue by placement of a stent following a surgical coronary arterial injury in a child.

An acute injury to a coronary artery was recognized during the surgical construction of the Fontan circulation. Surgical manipulation of the site of injury was not successful in restoring normal myocardial blood flow. A stent was therefore placed intraoperatively under direct vision, with restoration of normal coronary arterial flow acutely and at short-term follow-up.

Comparison of two spatially resolved NIRS oxygenation indices.

UNLABELLED: We compared the percentage haemoglobin oxygenation indices from two near infrared spectrophotometers (NIRS) to determine whether the devices reported similar changes in response to induced changes in oxygenation. METHODS: 24 healthy juvenile swine undergoing cardiac bypass surgery had INVOS 5100 and NIRO-300 sensors applied to the brow. Induced events included circulatory arrest, altered blood flow rate, core cooling, and re-warming. RESULTS: The average data collection was 4 hours 36 minutes and had an r = 0.82 mean correlation between the INVOS and NIRO. The total resting baseline collection from all trials (8,590 pairs) had a correlation of r = 0.62. The average relationship between the INVOS and NIRO was non-linear: an INVOS regional oxygen saturation index (rSO2) of 0% was equivalent to a NIRO tissue oxygenation index (TOI) of 36.2%; values were equal at 56.8%; and an (rSO2) of 100% was equivalent to a TOI 85.9%. There was good or excellent agreement (r > 0.5) between the (rSO2) and TOI patterns of change during induced events in 96% of trials. The INVOS and NIRO were most closely correlated when an attenuation filter was used to obtain identical emitter/detector separations. CONCLUSIONS: There was close agreement between the INVOS 5100 and NIRO-300 in response to major physiological change, although absolute values of (rSO2) and TOI were not identical. There was less agreement during baseline measurements or minimal physiologic change.

Compression of mediastinal structures treated by extra-anatomic bypass grafting.

Extra-anatomic bypass grafts have been used to treat complex and recurrent forms of coarctation of the aorta. Here we describe the use of an extra-anatomic bypass graft from the ascending to supraceliac aorta to treat an unusual complication of compression of mediastinal structures caused by a bucket handle graft.