Robert J. Dabal

The modern Fontan operation shows no increase in mortality out to 20 years: A new paradigm

OBJECTIVE Dating back to the first published report of the Fontan circulation in 1971, multiple studies have examined the long-term results of this standard procedure for palliation of single-ventricle heart disease in children. Although the technique has evolved over the last 4 decades to include a polytetrafluorethylene (PTFE) conduit for a large percentage of patients, the long-term outcome has not yet been established. The aim of the current study was to investigate the possibility of a late increasing risk for death after 15 years among patients with a modern Fontan operation and to evaluate late morbidity. METHODS Between January 1, 1988, and December 31, 2011, 207 patients underwent the Fontan procedure using an internal or external PTFE conduit plus a bidirectional cavopulmonary connection. Survival and late adverse events were analyzed. Risk factors for early and late mortality were examined using hazard function methodology. RESULTS At 1, 10, and 20 years, survival for the entire cohort was 95%, 88%, and 76%, respectively, with no deaths in the last 6 years of the study. Hazard modeling showed a 1.3% risk of death per year 24 years after the Fontan procedure, with no late increasing hazard phase. Freedom from reoperations was greater than 90% at 20 years and freedom from thrombotic complications was 98% at 20 years (with greater than 80% of patients on aspirin alone). Survival curves were superimposable for 16- to 20-mm conduits, and the freedom from any reoperation including transplantation was greater than 90% after 20 years. Multivariable risk factor analysis identified only earlier date of operation as a predictor of early and late mortality. By era of surgery, the 10-year predicated survival is 89% for patients undergoing surgery in 2000 and 94% for patients in 2010. CONCLUSIONS Early and late survival after a Fontan operation with a PTFE conduit is excellent, with no late phase of increasing death risk after 20 years. Late functional status is good, the need for late reoperation is rare, and thrombotic complications are uncommon on a standard medical regimen including aspirin as the only anticoagulation medication.

Prophylactic Peritoneal Dialysis Following Cardiopulmonary Bypass in Children Is Associated with Decreased Inflammation and Improved Clinical Outcomes

OBJECTIVE To investigate impact of prophylactic peritoneal dialysis (PD) on clinical outcomes and inflammatory cytokines in children following cardiac surgery with cardiopulmonary bypass. DESIGN Prospective before-and-after nonrandomized cohort study. SETTING Pediatric cardiovascular intensive care unit in tertiary hospital. PATIENTS Fifty-two consecutive neonates and infants at high risk for postoperative fluid overload following cardiopulmonary bypass. All had PD catheters placed during primary cardiac surgery. INTERVENTION Initial 27 patients were managed with passive peritoneal drainage and diuretics (controls). Following 25 patients were started on prophylactic PD in immediate postoperative period and managed per PD protocol (+PD). OUTCOME MEASURES Cumulative fluid balance, indices of disease severity, and clinical outcomes were prospectively collected. Plasma interleukin-6 and interleukin-8 were measured immediately before-and-after cardiopulmonary bypass and at 24 and 48 hours post-cardiopulmonary bypass. RESULTS Demographics, diagnoses, and intraoperative variables were similar. Median net fluid balance was more negative in +PD at 24 hours, -24 mL/kg (interquartile range: -62, 11) vs. +18 mL/kg (interquartile range: -26, 11), P = .003, and 48 hours, -88 mL/kg (interquartile range: -132, -54) vs. -46 mL/kg (interquartile range: -84, -12), P = .004. +PD had median 55 mL/kg less fluid intake at 24 hours, P = .058. Peritoneal drain, urine, and chest tube output were comparable over first 24 hours. Mean inotrope score was lower in +PD at 24 hours. +PD had earlier sternal closure--24 hours (interquartile range: 20, 40) vs. 63 hours (interquartile range: 44, 72), P < .001--and a trend toward shorter duration of mechanical ventilation--71 hours (interquartile range: 49, 135) vs. 125 hours (interquartile range: 70, 195), P = .10. +PD experienced lower serum concentrations of interleukin-6 and interleukin-8 at 24 hours. CONCLUSIONS Prophylactic PD is associated with greater net negative fluid balance, decreased inotrope requirements, and lower serum concentrations of inflammatory cytokines in the early postoperative period.

Early initiation of arginine vasopressin infusion in neonates after complex cardiac surgery.

Objective: To describe our experience with low-dose arginine vasopressin infusions (0.0003 U/kg/min) initiated in the operating room after the Norwood procedure or arterial switch operation. Design: Retrospective cohort study of 37 consecutive neonates. Setting: Pediatric cardiovascular intensive care unit in a tertiary hospital. Subjects: Nineteen patients that received low-dose arginine vasopressin infusion instituted in the operating room (arginine vasopressin+) were compared to 18 patients that did not receive early arginine vasopressin infusion (arginine vasopressin–). Interventions: None. Results: When comparing arginine vasopressin+ and arginine vasopressin− in the first 24 hrs after cardiovascular intensive care unit admission, there was no difference in demographic variables, heart rate, blood pressure, central venous pressure, maximum lactate, maximum arterial and central venous saturation difference, urine output, chest tube output, or peritoneal drain output. Mean fluid resuscitation in the first 24 hrs was significantly lower in the arginine vasopressin+ group compared to the arginine vasopressin− group (182 ± 61 mL/kg vs. 223 ± 53 mL/kg, p = .03). The arginine vasopressin+ group also reached median net negative cumulative fluid balance sooner (55 hrs: interquartile range 45, 74 vs. 76 hrs: interquartile range 69, 92; p = .02). Median maximum inotrope score in the first 24 hrs was significantly lower in arginine vasopressin+ (9: interquartile range 5, 12.5 vs. 16.5: interquartile range 10.3, 22.1; p = .02). There was a nonsignificant trend toward shorter duration of mechanical ventilation and cardiovascular intensive care unit length of stay in the arginine vasopressin+ group. The lowest serum sodium in the first 48 hrs was significantly lower in arginine vasopressin+ (132 vs. 137 mmol/L, p = .01). Conclusion: Low-dose arginine vasopressin infusion initiated in the operating room after complex neonatal cardiac surgery was associated with decreased fluid resuscitation and catecholamine requirements in the first 24 postoperative hours.

Postoperative Hydrocortisone Infusion Reduces the Prevalence of Low Cardiac Output Syndrome After Neonatal Cardiopulmonary Bypass.

Objective: Neonatal cardiac surgery with cardiopulmonary bypass is often complicated by morbidity associated with inflammation and low cardiac output syndrome. Hydrocortisone “stress dosing” is reported to provide hemodynamic benefits in some patients with refractory shock. Development of cardiopulmonary bypass-induced adrenal insufficiency may provide further rationale for postoperative hydrocortisone administration. We sought to determine whether prophylactic, postoperative hydrocortisone infusion could decrease prevalence of low cardiac output syndrome after neonatal cardiac surgery with cardiopulmonary bypass. Design: Double-blind, randomized control trial. Setting: Pediatric cardiac ICU and operating room in tertiary care center. Patients: Forty neonates undergoing cardiac surgery with cardiopulmonary bypass were randomized (19 hydrocortisone and 21 placebo). Demographics and known risk factors were similar between groups. Interventions: After cardiopulmonary bypass separation, bolus hydrocortisone (50 mg/m2) or placebo was administered, followed by continuous hydrocortisone infusion (50 mg/m2/d) or placebo tapered over 5 days. Adrenocorticotropic hormone stimulation testing (1 &mgr;g) was performed before and after cardiopulmonary bypass, prior to steroid administration. Blood was collected for cytokine analysis before and after cardiopulmonary bypass. Measurements and Main Results: Subjects receiving hydrocortisone were less likely to develop low cardiac output syndrome (5/19, 26% vs 12/21, 57%; p = 0.049). Hydrocortisone group had more negative net fluid balance at 48 hours (–114 vs –64 mL/kg; p = 0.01) and greater urine output at 0–24 hours (2.7 vs 1.2 mL/kg/hr; p = 0.03). Hydrocortisone group weaned off catecholamines and vasopressin sooner than placebo, with a difference in inotrope-free subjects apparent after 48 hours (p = 0.033). Five placebo subjects (24%) compared with no hydrocortisone subjects required rescue steroids (p = 0.02). Thirteen (32.5%) had adrenal insufficiency after cardiopulmonary bypass. Patients with adrenal insufficiency randomized to receive hydrocortisone had lower prevalence of low cardiac output syndrome compared with patients with adrenal insufficiency randomized to placebo (1/6 vs 6/7, respectively; p = 0.02). Hydrocortisone significantly reduced proinflammatory cytokines. Ventilator-free days, hospital length of stay, and kidney injury were similar. Conclusions: Prophylactic, postoperative hydrocortisone reduces low cardiac output syndrome, improves fluid balance and urine output, and attenuates inflammation after neonatal cardiopulmonary bypass surgery. Further studies are necessary to show if these benefits lead to improvements in more important clinical outcomes.

The effect of left internal mammary artery utilization on short-term outcomes after coronary revascularization

BACKGROUND The purpose of this study was to determine whether use of the left internal mammary artery (LIMA) during coronary revascularization influences short-term morbidity in all patients undergoing revascularization, as well as in patients over the age of 75 years, female patients, and patients with diabetes. The study also explored variability in the utilization of LIMA grafts across an entire state. METHODS Using the Clinical Outcomes Assessment Program (COAP) of the state of Washington, procedural outcomes were compared for patients receiving and patients not receiving LIMA grafts as part of revascularization procedures from January 1, 1999 to December 31, 2000. Mortality and major complications were examined, both as unadjusted rates and after adjusting for baseline patient risk factors. RESULTS A total of 16 centers performed 8,797 nonemergent coronary artery revascularizations, including 81.7% with LIMA grafts. The use of a LIMA graft was associated with a significantly lower mortality (3.7% No LIMA vs 1.6% LIMA), as well as decreases in ventricular arrhythmias, need for postoperative dialysis, need for transfusions, ventilator dependence, and length of hospital stay. These trends were true for the population as a whole as well as for all subgroups analyzed, and they persisted after correcting for differences in comorbid conditions. In addition, there was wide variability in the use of LIMA grafts from center to center in the state. CONCLUSIONS The use of LIMA grafts for coronary revascularization is associated with decreased mortality and morbidity. Despite these advantages, there is great variability in its application across the state of Washington.

Ultrasound-guided femoral vein catheterization in neonates with cardiac disease*.

Objective: To describe a novel technique for real-time, ultrasound-guided femoral vein catheterization in neonates with cardiac disease, and to compare it to a contemporaneous cohort of neonates undergoing femoral vein central venous line placement via landmark technique. Design: Retrospective cohort study of data extracted from a quality improvement database. Setting: Pediatric cardiac intensive care unit and cardiovascular operating room in pediatric tertiary hospital. Patients: One hundred fifteen neonates (mean weight, 3.07 ± 0.41 kg) with cardiac disease who underwent femoral central venous line attempts from January 2009 to September 2011. Measurements and Main Results: Study populations were similar in age, weight, and Risk Adjustment for Congenital Heart Surgery-1 category, but differed in intubation status (32% vs. 100%, ultrasound vs. landmark, p < .0001). Central venous line success rate was superior in the ultrasound group: 72 of the 76 (94.7%) vs. 31 of the 39 (79.5%), p = .02. Ultrasound group also had a superior first (75% vs. 30.8 %) and second attempt success rate (90.8% vs. 51.3%), p value for both < .0001. Inadvertent arterial puncture occurred less frequently in the ultrasound group: four of the 76 (5.3%) vs. nine of the 39 (23.1%), p = .01. There was a trend toward more venous thrombosis in the landmark group, 16 of the 39 (41%) vs. 18 of the 76 (23.7%), p = .08. Among all 115 subjects, there was a very strong association between greater than two central venous line attempts and the odds of being diagnosed with a deep venous thrombosis (odds ratio, 9.3; 95% confidence interval 3.5–24.8) and the odds of suffering an inadvertent femoral arterial puncture during the central venous line event (odds ratio, 8.8; 95% confidence interval 10.6–730). Conclusions: This novel long-axis real-time ultrasound technique facilitates placement of femoral vein central venous line in critically ill neonates with cardiac disease at a higher rate of success with fewer attempts and lower occurrence of complications when compared with the landmark technique.

Mechanical Circulatory Support: Strategies and Outcomes in Pediatric Congenital Heart Disease

Patients with acute or progressive heart failure in the setting of congenital heart disease may need mechanical circulatory support (MCS) to enhance survival while awaiting cardiac transplantation. Because the majority of MCS devices are implanted after prior cardiac operations, special precautions are necessary at the time of implant. MCS in single ventricle patients usually requires ventricular and aortic cannulation, with a systemic to pulmonary artery shunt for pulmonary blood flow. Limited outcomes data is available, with less than 15% of pediatric MCS patients having congenital heart disease. The Berlin EXCOR is the only durable device currently available for infants. Neurologic complications are the major cause of mortality, and survival during support is poor for infants <5 kg. Patients post-Fontan with acute cardiac failure and/or respiratory failure are at high risk for death before transplant and should be considered for MCS therapy. Several emerging miniature continuous flow devices will soon broaden the landscape of available pediatric devices.

Preoperative Trophic Feeds in Neonates with Hypoplastic Left Heart Syndrome

OBJECTIVE The aim of this is study is to determine if preoperative trophic feeds (TFs) can improve outcomes after Norwood palliation. DESIGN This is a retrospective cohort study. SETTING The setting is a pediatric cardiovascular intensive care unit in a tertiary hospital. PATIENTS The patients were 50 consecutive patients with hypoplastic left heart, excluding 5 patients with prematurity or other significant comorbidities. Thirty-one patients that received preoperative TFs (20-30 mL/kg) were compared with 14 that remained nothing by mouth. Decision to initiate feeds was based on attending preference. All patients had protocolized feeds postoperatively, with initiation via transpyloric tube when patient was on minimal inotropes. OUTCOME MEASURES Demographic, feeding, and other clinical outcome data were collected retrospectively from the patient medical record. RESULTS There were no differences in demographics or preoperative risk factors (mechanical ventilation and lowest pH) between the two groups. Overall survival to discharge was 78% (25/31 TF, 10/14 nothing by mouth, P = .7). Neonates receiving TFs had less fluid administration in the cardiovascular operating room (P = .002), a more negative 48-hour postoperative fluid balance (P = .03), and median 3 days shorter duration of mechanical ventilation (P = .006). Trophic feeds patients also had a nonsignificant trend toward lower peak lactic acid (P = .06), lower inotropic score (P = .15), shorter hospital length of stay (P = .19), and faster time to tolerance of full enteral and oral feeds by 3 and 8 days, respectively (P = .06 and .01). There were no episodes of necrotizing enterocolitis in either group. CONCLUSIONS Preoperative TFs before Norwood palliation appear safe and are associated with shorter duration of mechanical ventilation, a trend toward more stable postoperative hemodynamics, less fluid overload, and earlier postoperative feeding tolerance.

Central Venous Lines Are a Risk Factor for Chylothorax in Infants After Cardiac Surgery

Objective: Chylothorax complicates congenital heart disease (CHD) surgery and may be associated with significant morbidity. Etiology of chylothorax is multifactorial, and it has been associated with deep venous thrombosis and obstruction from central venous lines (CVLs) in patients without CHD. We sought to determine whether CVL insertion site was associated with the occurrence of chylothorax in infants after cardiac surgery. Design: Retrospective cohort of patients less than one year of age who underwent CHD surgery requiring cardiopulmonary bypass from 2008 to 2012. Chylothorax was identified by clinical diagnosis and/or laboratory findings (milky effusion, fluid with >100 mg/dL of triglycerides and/or >80% of lymphocytes). Central venous lines insertion site was verified by reviewing procedure notes and chest x-rays. Internal jugular (IJ), subclavian vein, and femoral vein (FV) CVLs were used during the study period. Results: Three hundred and ninety-two patients were included (mean age 97 days, mean weight 4.5 kg). Sixty-two (15.8%) of these patients developed chylothorax after surgery. Patients with chylothorax had longer bypass time (P = .02), longer cross-clamp time (P = .03), higher RACHS-1 category (P = .03), and more frequent upper body CVLs (IJ or subclavian vein; P = .03). There was no significant association with age, gender, preoperative weight, and height. Multivariate analysis showed patients with a CVL in the upper body (IJ or subclavian vein) were almost two times more likely to develop a chylothorax than patients who had FV CVL, (odds ratio = 1.9, 95% confidence interval = 1.05-5.60; P = .044). Conclusion: Postoperative chylothorax is associated with line insertion in the upper body (subclavian vein and IJ). Avoidance of CVLs in these locations may decrease its incidence.

Cardiac transplantation and mechanical support for functional single ventricle.

Cardiac transplantation has played a pivotal role in the therapeutic algorithm for anatomically uncorrectable congenital heart disease, particularly the failing single ventricle. The historical evolution from Kantrowitz to Bailey and beyond challenges the application of this scarce resource to complex cardiac malformations in the presence of physiologic and circulatory failure. While selection of cardiac transplantation as primary therapy for hypoplastic-left heart syndrome is currently rare, the failing single ventricle in various stages of the Fontan pathway is increasingly considered for this therapy. The results of transplantation in this complex situation have progressively improved and now approached the late outcomes for other conditions. Mechanical circulatory support for the failing single ventricle has recently carried infants and children to successful transplant. The development of miniaturized continuous flow pumps offers the hope of major new avenues of successful circulatory support for single ventricle patients.