Long-term anticoagulation in Kawasaki disease: Initial use of low molecular weight heparin is a viable option for patients with severe coronary artery abnormalities.

Patients with severe coronary artery involvement after Kawasaki disease (KD) require long-term systemic anticoagulation. We sought to compare our experience with thrombotic coronary artery occlusions, safety profile, and degree of coronary artery aneurysm regression in KD patients treated with low molecular weight heparin (LMWH) versus warfarin. Medical records of all KD patients diagnosed between January 1990 and April 2007 were reviewed. Of 1374 KD patients, 38 (3%) received systemic anticoagulation, 25 patients received LMWH from diagnosis onward, 12 of whom were subsequently switched to warfarin, and 13 received warfarin from onset. The frequency of thrombotic coronary artery occlusions was similar between drugs. Severe bleeding was more frequent in patients on warfarin, but minor bleeding was more frequent for patients on LMWH. Patients on warfarin were at greater risk of underanticoagulation or overanticoagulation (defined as achieving an anti-activated factor X level or an international normalized ratio below or above target level) than patients on LMWH (P < 0.05). Maximum coronary artery aneurysm z-scores diminished with time for patients on LMWH (P = 0.03) but not for those on warfarin (P = 0.55). This study suggests that LMWH is a potentially viable alternative for patients, especially young ones, with severe coronary artery involvement after KD.

Exercise capacity improves with time in pediatric heart transplant recipients.

BACKGROUND: The purpose of this study was to profile the exercise capacity of pediatric heart transplant recipients over time and to identify factors associated with lower exercise capacity. METHODS: Pediatric heart transplant (HTx) recipients >6 years of age underwent annual cycle ergometry exercise testing (GXT). Exercise testing values were converted to percent predicted based on age and gender when available. Linear regression analysis adjusted for repeated measures was used to determine trends over time and associated factors. RESULTS: A total of 58 patients (34 males, 59%) had 202 GXTs (2 to 8 years post-transplant). The mean percent predicted maximum heart rate (HR) response was 76 +/- 10% predicted, increased non-linearly with time post-transplant (p<0.0001), and was associated with a higher resting HR, longer time post-transplant and older age at transplant. Mean percent predicted workload was 66 +/- 15%, mildly below normal controls. Mean maximum oxygen consumption (VO(2)max) was 30 +/- 8 ml/kg/min and was found to be influenced over time by an interaction between age at transplantation and time since transplant. Greater systolic blood pressure (BP) response was associated with longer time post-transplant and higher resting systolic BP. Overall, pediatric heart transplant is associated with good exercise capacity. Younger age at transplant is associated with greater exercise capacity (VO(2)max). Serial trends in HR, BP response and VO(2)max may provide supportive evidence for graft reinnervation. Deterioration in VO(2)max was associated with graft loss because of vasculopathy. CONCLUSION: The utility of serial routine GXT in pediatric heart transplant recipients warrants further study, especially for its role in the detection of graft vasculopathy.

Arterial complications associated with cardiac catheterization in pediatric patients with a previous history of Kawasaki disease.

OBJECTIVES: To determine whether patients with Kawasaki Disease (KD) undergoing percutaneous catheter angiography were at increased risk of arterial complications at the point of arterial access compared to patients with structural heart abnormalities, but normal vessels. BACKGROUND: Systemic arterial damage can occur as a result of KD. METHODS: Medical histories of all patients with KD undergoing percutaneous catheter angiography at The Hospital for Sick Children between January 1990 and August 2008 were reviewed. RESULTS: A total of 44 patients with KD underwent 82 catheter procedures. Of these, 3 were associated with important arterial complications (2 males; age: 4 months, 3 and 17 years). All patients who experienced complications had multiple large and/or giant coronary artery aneurysms and two were within 3 months of the acute phase of KD. All patients developed pseudoaneurysms of the femoral artery which had been utilized for catheter access. All pseudoaneurysms were treated with ultrasound-guided thrombin injection and compression, and resolved with no long-term complications. One patient also developed a substantial arteriovenous fistula of the femoral circulation which had to be surgically repaired with no permanent sequela. Odds for arterial complications in patients with KD were 10.4 times greater (95%CI: 3.2-33.8) than that noted for the general pediatric cardiac catheterization population (3.6% vs. 0.4%, P < 0.0001) which indicates higher risk associated with arterial access in patients with KD. CONCLUSIONS: Greater care in obtaining arterial access for angiography is warranted, especially in the first month directly following the acute phase, possibly related to systemic arterial damage associated with KD.

Spectrum and management of hypertriglyceridemia among children in clinical practice.

OBJECTIVES: The prevalence and identification of hypertriglyceridemia in youths will likely will increase in the future as a consequence of childhood obesity and increased screening for dyslipidemias. We sought to review our clinical experience with hypertriglyceridemia, evaluate factors associated with increased triglyceride levels, and review treatment options to provide guidance for management. METHODS: Clinical review of data for all patients who had > or =1 elevated triglyceride level (>4 mmol/L [>350 mg/dL]) while being monitored in a specialized lipid disorders clinic was performed. RESULTS: The study population consisted of 76 patients with 761 clinic visits. Hypertriglyceridemia was secondary to lifestyle factors for 13 patients. The rest had primary hypertriglyceridemia, with 32 patients having familial combined hypertriglyceridemia and hypercholesterolemia (type II), 25 patients having primary hypertriglyceridemia (type IV), 4 patients having familial lipase deficiency (type I), and 2 patients having hyperlipoproteinemia E2/E2 phenotype (type III). Triglyceride levels were highest in type I and III hypertriglyceridemia (>10 mmol/L [>900 mg/dL]), followed by type IV and adiposity-related hypertriglyceridemia (>4 mmol/L [>350 mg/dL]) and finally type II familial combined hypertriglyceridemia and hypercholesterolemia (>2 mmol/L [>180 mg/dL]). A total of 34 patients received 37 trials of drug therapy as part of triglyceride level management (bile acid-binding resins, n = 12; fibrates, n = 19; statins, n = 6). Triglyceride levels were found to decrease over time with the use of fibrates, to increase with the use of bile acid-binding resins, and not to change with the use of statins. CONCLUSIONS: Lifestyle modifications remain the primary therapeutic avenue for the management of pediatric hypertriglyceridemia. We propose an algorithm for the management of this heterogeneous population to guide clinicians in their treatment decisions.

Clinical impact of vasopressin infusion on hemodynamics, liver and renal function in pediatric patients.

OBJECTIVE: To study effects of vasopressin on hemodynamic, clinical, and laboratory variables in children with advanced vasodilatory shock. DESIGN AND SETTING: Retrospective study in a multidisciplinary tertiary pediatric critical care unit. PATIENTS AND PARTICIPANTS: Patients (n = 117; 32 noncardiac, 85 postcardiac surgery) requiring intravenous vasopressin infusion longer than 60 min for advanced shock (January 2004 to December 2005). INTERVENTIONS: Vasopressin infusion (n =157). MEASUREMENTS AND RESULTS: Both cardiac and noncardiac patients showed a significant decrease in inotrope requirement without change in central venous saturation or lactate during infusion. Both groups had increased urea and creatinine and decreased urine output with longer duration/higher cumulative dose of vasopressin. There was a significant increase in conjugated bilirubin level in the noncardiac group during vasopressin infusion; noncardiac patients showed higher AST levels with higher cumulative dose or longer duration of infusion. Postcardiac surgical patients showed a trend towards normal INR values which persisted after vasopressin infusion. Platelet counts were significantly lower during infusion in both groups. CONCLUSIONS: Vasopressin infusion improved the hemodynamic state in advanced shock without compromising cardiac function. Urine output and creatinine levels were adversely affected but were reversible. This effect was more pronounced with higher dose or duration of infusion. There was no major effect on liver function but a significant reduction in platelet counts. These data suggest that vasopressin is useful in states of vasodilatory shock with limitations regarding to its adverse renal effects and on platelet counts.

Outcome and growth potential of left heart structures after neonatal intervention for aortic valve stenosis.

OBJECTIVES: The purpose of this study was to determine trends of growth of left heart structures after intervention for neonatal aortic valve stenosis. BACKGROUND: The growth potential of left heart structures in neonatal aortic valve stenosis after relief of obstruction might influence risk for subsequent outcomes. METHODS: From 1994 to 2004, 53 patients underwent neonatal (< or =30 days old) balloon aortic valve dilation. Factors associated with time-related outcomes (death, reintervention, aortic valve replacement) and longitudinal changes in normalized left heart dimensions were sought. RESULTS: The median age at intervention was 3.5 days (range 1 to 30 days). During a median follow-up of 3.2 years ranging up to 10.9 years, there were 31 reinterventions on the aortic valve in 21 (40%) patients and 7 deaths (13%). The presence of moderate or severe left ventricular (LV) endocardial fibroelastosis was the only independent predictor for time-related mortality (hazard ratio 22.1; p = 0.004), and a smaller initial aortic valve annulus z-score was a significant independent predictor for aortic valve replacement (hazard ratio 0.63 per 1-U change; p = 0.007). Aortic valve annulus, aortic sinus, and LV dimension z-scores significantly increased over time, whereas mitral valve z-scores remained below normal. The structure's initial z-score and concomitant size of other left heart structures were significant independent factors associated with subsequent z-scores. CONCLUSIONS: There is potential catch-up growth of the aortic valve and LV over time for neonates after intervention for aortic valve stenosis. However, the continued hypoplasia of the mitral valve warrants further consideration in the long-term management of these patients.

Prevalence and associated risk factors for intervention in 313 children with subaortic stenosis.

BACKGROUND: We sought to determine the prevalence of intervention and associated factors in children presenting with subaortic stenosis. We also investigated whether a protocol adopted in 1994 of early subaortic resection at a preoperative mean systolic gradient across the left ventricular outflow tract (LV gradient) greater than 30 mm Hg was supported by longitudinal outcomes. METHODS: Record review of all children (n = 313) diagnosed with subaortic stenosis was conducted between 1975 and 1998 at our institution. Cox proportional hazard models determined the prevalence and associated factors for initial subaortic resection. Mixed models of serially obtained echocardiographic data (n = 933) established longitudinal LV gradient trends and identified factors associated with more rapid LV gradient progression. RESULTS: Median age at presentation was 8 months. Freedom from initial subaortic resection was 40% at 16 years from diagnosis. Earlier progression to subaortic resection was associated with patient characteristics at presentation, including a higher initial LV gradient (p < 0.001), larger aortic annulus z-score (p = 0.005), smaller body surface area (p < 0.001), and smaller mitral annulus z-score (p = 0.003). Initial resection was also associated with a faster rate of LV gradient progression (p = 0.003). Factors determining the increased rate of LV gradient progression included an initial LV gradient greater than 30 mm Hg (p < 0.001), initial aortic valve thickening (p = 0.003), and attachment of subaortic stenosis to the mitral valve (p = 0.003). Worse aortic regurgitation grade with time was also associated with an initial LV gradient greater than 30 mm Hg (p < 0.001). CONCLUSIONS: Subaortic resection should be delayed until the LV gradient exceeds 30 mm Hg because most children with an initial LV gradient less than 30 mm Hg have quiescent disease.

Factors associated with mortality and reoperation in 377 children with total anomalous pulmonary venous connection.

BACKGROUND: We sought to determine era-specific changes in the incidence of mortality and reoperation in children with total anomalous pulmonary venous connection. METHODS AND RESULTS: We reviewed the records of 377 children presenting from 1946 to 2005 with total anomalous pulmonary venous connection. Multivariable parametric regression models determined the incidence and risk factors for death and reoperation after repair. Pulmonary venous connection was supracardiac in 44%, infracardiac in 26%, cardiac in 21%, and mixed in 9%. Pulmonary venous obstruction was present in 48% at presentation, most frequently with infracardiac connection type (P<0.001). In total, 327 patients were repaired (median age, 1.7 months). Overall survival from repair was 65+/-6% at 14 years, with a current survival of 97%. Significant (P<0.01) incremental risk factors for postrepair death were cardiac connection type, earlier operation year, younger age at repair, use of epinephrine postoperatively, and postoperative pulmonary venous obstruction. More recent operation year was associated with younger age at repair (P<0.001), decreased use of deep hypothermic circulatory arrest (P<0.001), and use of specific drugs postoperatively (P<0.001). Risk-adjusted estimated 1-year survival for a patient repaired at birth with unfavorable morphology in 2005 is 37% (95% CI, 8 to 80) compared with 96% (95% CI, 91 to 99) for a patient with favorable morphology repaired at 1 year of age. Freedom from reoperation was 82+/-6% at 11 years after repair, with increased risk associated with mixed connection type (P=0.04) and postoperative pulmonary venous obstruction (P<0.001). CONCLUSIONS: Mortality after total anomalous pulmonary venous connection repair has decreased but remains highest in young patients and in those with cardiac connection type or pulmonary venous obstruction. Unfavorable anatomic characteristics remain important determinants of postrepair survival despite improved perioperative care.

Management and outcomes of double aortic arch in 81 patients.

OBJECTIVES: Double aortic arch is a common form of complete vascular ring, encircling both the trachea and esophagus, resulting in noncardiac morbidity. We sought to describe management and outcomes in a large single institution clinical series. PATIENTS AND METHODS: We reviewed the medical charts of all of the patients diagnosed with double aortic arch at age <18 years. Data regarding clinical presentation, anatomy, management, and outcomes were abstracted. RESULTS: We identified 81 patients (67% males) born between 1964 and 2005 and presenting at a median age of 5 months (range: birth to 10.3 years). Respiratory symptoms were present in 91%, including stridor in 77%. Gastrointestinal symptoms were present in 40%, with choking with feeds being most common. The dominant branch of the double aortic arch was right in 72%. Associated cardiac anomalies were present in 18%, with noncardiac anomalies in 7%. Repair was performed in 79 patients at a median age of 6 months. There were 2 deaths after surgical repair with no late deaths, with Kaplan-Meier survival estimates of 96% at 5 years. Postoperative complications included chylothorax in 9%. Only 1 patient required reoperation. The most common symptoms at most recent follow-up were respiratory (54%) followed by gastrointestinal symptoms (6%). Postoperative tracheal stenosis was documented in 14%, with tracheomalacia in 7%. There were no late reoperations and no evidence of aortic arch obstruction. CONCLUSIONS: Outcomes are excellent after repair of double aortic arch, although persistent respiratory symptoms are frequent and probably associated with previous compression-related maldevelopment of the trachea and major airways.