Undergone Fontan Palliation Research Articles

Anesthesia for pheochromocytoma resection in a child with Fontan circulation

To report the anesthetic management of a successful resection of a pheochromocytoma in a child with a completed Fontan circulation. The patient was an 11-yr-old boy with Ivemark syndrome who had undergone Fontan palliation at three years of age. Six weeks earlier, he had been diagnosed with a norepinephrine-producing pheochromocytoma, and he had been pretreated with oral propranolol and phenoxybenzamine. During surgery, intravenous administration of magnesium sulphate, esmolol, and phentolamine provided good hemodynamic control. Postoperatively, the patient tended to be hypotensive, and treatment with fluid administration resulted in prolonged intensive care. Although intraoperative management was not problematic, postoperative care of this 11-yr old child with pheochromocytoma was complicated by residual sympathetic blockade.

Two-Dimensional Speckle Strain and Dyssynchrony in Single Right Ventricles Versus Normal Right Ventricles

Patients with single-right ventricle (RV) physiology are at increased risk for myocardial dysfunction and mechanical dyssynchrony. Newer echocardiographic modalities may be better able to quantitate right ventricular function in this unique population. The aim of this study was to use two-dimensional speckle analysis of strain and strain rate to quantify systolic function and dyssynchrony in single-RV post-Fontan patients and compare them with values for controls. Patients with single RV who underwent Fontan palliation and patients with normal biventricular anatomy were studied. Two-dimensional speckle echocardiography was used to measure strain, strain rate, time to peak, and longitudinal displacement in a 6-segment model of the RV. Independent t tests were used to compare group means. P values < .05 were considered significant. Thirteen patients were studied in each group. There was no significant difference in age between single-RV patients and controls (6.60 +/- 2.07 vs 5.75 +/- 1.83 years, respectively). Single-RV strain values were significantly lower in all 6 segments compared with values in controls (basal interventricular septum [IVS], -14.28 +/- 7.78% vs -22.00 +/- 2.36%; mid IVS, -17.70 +/- 4.54% vs -22.99 +/- 2.71%; apical IVS, -19.46 +/- 4.97% vs -25.42 +/- 4.06%; basal RV, -22.40 +/- 5.7% vs -41.42 +/- 5.42%; mid RV, -21.20 +/- 3.21% vs -39.67 +/- 6.04%; apical RV, -20.70 +/- 4.90% vs -33.68 +/- 3.90%). Systolic strain rate and longitudinal displacement were also lower in the free wall and apical IVS in single-RV patients compared with controls. The modified Yu index for strain time to peak was longer in the single-RV patients (43.16 +/- 13.63 vs 21.72 +/- 7.25 ms). Significant differences in strain analysis between single-RV patients and patients with biventricular physiology exist at a relatively young age. Future studies are needed to determine the clinical significance of these differences.

Risk Factors for Cerebrovascular Events Following Fontan Palliation in Patients With a Functional Single Ventricle

The risk for cerebrovascular events (CVEs) is increased in children with functional single ventricles (FSVs). However, there are limited data indicating the prevalence of CVEs or the role of preventative therapy. To measure the prevalence of clinically evident CVEs in patients with FSVs, identify risk factors, and analyze the effect of aspirin on the risk for CVEs, a retrospective chart review was performed on all patients who underwent Fontan palliation at the University of Michigan from January 1, 1975, to June 30, 1998 (n = 402). Data collected included original anatomy, Fontan type, date of CVE, medications at the time of CVE, intraoperative placement of fenestration, and date of last follow-up. The overall mortality rate was 12%. There were 38 CVEs (9%), of which only 11 (3%, or 0.0036/patient-year) could not be attributed to a defined event (catheterization, extracorporeal membrane oxygenation, or cardiac arrest). Anticoagulation with aspirin was associated with a statistically significantly decreased risk for CVEs. Fontan type was not associated with the risk for CVEs. Thus, patients with FSVs are at increased risk for CVEs, although the de novo risk was low. Aspirin use is associated with a decreased risk for CVEs.

Anticoagulation and incidence of late cerebrovascular accidents following the Fontan procedure.

Thromboembolic events are a well-reported complication following the Fontan procedure, but no previous studies have compared the incidence of thromboembolic events relative to the prophylactic anticoagulation strategy utilized. We examined the time-adjusted incidence of late thromboembolic events relative to chronic anticoagulation strategy. All patients who have undergone Fontan palliation and are followed at our institution were reviewed. All thromboembolic and major bleeding events were recorded and compared among different subgroups (anticoagulant medication utilized, Fontan variant, and the presence of a residual right-to-left shunt). The incidence of late cerebrovascular accidents (CVAs) per patient-year was calculated for each subgroup. The records of 132 patients were analyzed (median follow-up, 7.6 years; 1066.5 total patient-years). There were no major bleeding complications. One patient receiving no anticoagulation therapy developed a symptomatic thrombus 6 months after Fontan. Three patients suffered late CVAs (range, 3-7 years); 2 were receiving aspirin, and the other received no anticoagulation therapy. All 3 had lateral tunnel Fontan and a residual right-to-left shunt. The overall incidence of late CVA was 2.3%, with an event rate of 0.28% per patient-year. Late CVA was not related to anticoagulation strategy or time from Fontan procedure but was associated with a residual right-to-left shunt and lateral tunnel-type Fontan palliation (p < 0.001). Regardless of anticoagulation strategy utilized, symptomatic CVA is a rare long-term complication following the Fontan procedure.

Effect of high-dose spironolactone on protein-losing enteropathy in patients with Fontan palliation of complex congenital heart disease

Protein-losing enteropathy (PLE) is a debilitating condition that occurs as a late complication in 5% to 10% of children who have undergone Fontan palliation of their complex congenital heart disease.1–4 It is characterized by loss of protein in the stool, resulting in hypoproteinemia, edema, and ascites. A chronic state of malnutrition may ensue and mortality can result if left untreated. PLE may occur secondary to markedly elevated central venous (Fontan pathway) pressure and may respond to reduction in venous pressure by interventions such as enlargement of narrowed pulmonary arteries, occlusion of extensive aorticopulmonary collateral arteries, or by creation of a fenestration allowing decompression into the systemic circulation. Many cases of PLE, however, are not associated with unfavorable Fontan hemodynamics and thus are not relieved by catheterization interventions. Remission of PLE has been reported with systemic corticosteroid therapy,5–7 but beneficial effects may be short-lived. Long-lasting relief has been reported by systemic administration of unfractionated heparin,8 but induction of severe osteoporosis may limit long-term use of this treatment. Takedown of the Fontan pathway and/or heart transplantation have become the therapy of last resort for some patients. We now report 3 children who developed PLE after their Fontan palliations and achieved remission after initiation of high-dose spironolactone therapy (Table 1).

Neurodevelopmental Outcomes in Children After the Fontan Operation

Background Previous studies of patients after the Fontan operation have reported IQ scores lower than population norms. In the past decade, changes have occurred both in surgical methods used and in the patient population undergoing Fontan palliation. The present study examined the impact of these changes on neurodevelopmental outcomes after Fontan. Methods and Results Neuropsychological tests were administered to 27 five-year-old children after Fontan. Mean age at repair was 2 years 4 months. The present sample was compared with an earlier Fontan group (EFG) of 133 patients who underwent surgery in the 1970s and 1980s. Mean age at repair for the EFG was 7 years 3 months. Compared with EFG, the present study sample was younger at Fontan ( P =0.0001) and more likely to have undergone a Norwood procedure ( P =0.02), a pre-Fontan bidirectional cavopulmonary anastomosis ( P &lt;0.001), and Fontan fenestration ( P =0.001). Although mean full-scale, verbal, and performance IQ scores were within 1 SD (15 points) of the population mean of 100 (93±16, 95±15, and 91±17, respectively), mean full-scale and performance IQ scores were significantly lower than this population mean ( P =0.03 and P =0.01, respectively). Conclusions Compared with a historical cohort of Fontan patients from this institution, a staged approach to Fontan earlier in life is not detrimental to neurodevelopmental outcome. Neurodevelopmental outcomes in children after Fontan are in the normal range, but performance remains lower than the general population.

MODIFIED MAXIMAL CYCLE ERGOMETRY TEST PROTOCOL FOR PATIENTS WITH UNIVENTRICULAR HEART AFTER FONTAN PALLIATION

Patients undergoing Fontan palliation have a markedly decreased working capacity when evaluated by exercise testing with existing protocols and maximal exercise tests are difficult to obtain. Eight patients post Fontan palliation (5 males, 3 females) were tested using the standard James protocol followed by a Modified Cycle Ergometry Protocol (MCEP) designed to elicit a maximal exercise response in these patients. The two exercise tests were separated by an average of 3.9 (+/−2.1) years. There was a significant increase in height, weight and body surface area at the time of the MCEP test. The average exercise time, working capacity and maximal heart rate (MHR) were significantly higher in the MCEP (p < .05) versus the James protocol. The average exercise time, working capacity and MHR for the MCEP versus the James protocol were 10.8 versus 6.2 minutes, 775 versus 363 watts and 172 versus 163 bpm, respectively. A maximal exercise test defined as respiratory quotient greater than 1.1, MHR greater than 85% of age expected and rating of perceived exertion greater than 17 was obtained in 8 of 8 patients with the MCEP versus 4 of 8 with the James protocol (p < .05). Although patients following Fontan palliation have a decreased working capacity, these data suggest that the MCEP can elicit a maximal exercise test more often than the standard James protocol thus improving exercise prescription and longitudinal follow-up.

Early results of the Fontan procedure in one hundred consecutive patients with hypoplastic left heart syndrome

Objectives: The purpose of this study was to review a large, single institutional experience with the Fontan procedure for patients with hypoplastic left heart syndrome. Methods: One hundred consecutive patients with “classic” hypoplastic left heart syndrome underwent Fontan palliation between February 1992 and April 1998. Patient demographic, morphologic, and procedural variables were examined and analyzed. In particular, two different surgical techniques were used: technique I (February 1992 to December 1995) employed cardiopulmonary bypass and moderate systemic hypothermia, and technique II (December 1995 to April 1998), profound hypothermia and circulatory arrest. A retrospective review of medical records was performed and variables were examined and analyzed. Results: Hospital survival for the entire cohort was 89% (95% CI 83%-95%). The technique of operation, cardiopulmonary bypass time, and aortic crossclamp time were each strongly associated with survival. Survival for patients treated by technique I was 79% (95% CI 68-91%; n = 48) and for those treated by technique II, 98% (95% CI 94%-100%; n = 52). Cardiopulmonary bypass and crossclamp times were also highly correlated with time to extubation and length of intensive care unit stay. Preoperative pulmonary artery pressure was correlated with survival; preoperative oxygen saturation, right atrial pressure, pulmonary vascular resistance, pulmonary artery size, extent of aortopulmonary artery collaterals, and echocardiographic estimates of ventricular function and tricuspid regurgitation were not correlated with survival. Conclusions: Our recent experience with Fontan palliation for patients with hypoplastic left heart syndrome suggests that it is attended by low perioperative mortality. The precise operative technique used appears to be an important determinant of outcome, with the duration of cardiopulmonary bypass and crossclamping being particularly significant. (J Thorac Cardiovasc Surg 2000;119:1110-8)

Influence of age on the effect of bidirectional cavopulmonary anastomosis on left ventricular volume, mass and ejection fraction

We sought to identify age-related differences in the ventricular response of patients after bidirectional cavopulmonary anastomosis (CPA) and to compare changes in the ventricular response among children < 3 years of age who underwent CPA with that of age-matched control subjects who had a systemic to pulmonary artery shunt alone. Pre-Fontan CPA has been advocated over a systemic to pulmonary artery shunt alone in patients with a single ventricle to facilitate ventricular volume unloading and minimize risk of the Fontan operation. Our study evaluated 23 patients who initially received a systemic to pulmonary artery shunt as an initial procedure before subsequent Fontan palliation. In eight of these patients (group I), bidirectional CPA was performed before age 3 years, and in four (group II), it was performed after age 10 years. The remaining 11 patients (group III, age and weight control group for group I) were maintained with their initial shunt until they underwent Fontan palliation. Serial echocardiographic analysis was used retrospectively to evaluate left ventricular volume and mass and systolic pump function (ejection fraction) before and after bidirectional CPA. Through 10 months of follow-up, group I patients showed significant decreases in indexed end-diastolic volume both after CPA (120 ml/m1.5 body surface area vs. 78 ml/m1.5, p = 0.001) and in comparison with values in patients in group II and III, who showed no changes in end-diastolic volume (p < 0.001). Indexed ventricular mass decreased moderately after bidirectional CPA in group I (from 228 g/m1.5 body surface area to 148 g/m1.5) but remained unchanged in groups II and III. The differences in trends between groups I and III were significant (p = 0.03). Ejection fraction decreased significantly in group II versus group I patients (0.48 to 0.27 vs. 0.51 to 0.52, p < 0.05) after CPA. Oxygen saturation measurements before and after bidirectional CPA revealed a significant increase in group I (73% to 86%, p < 0.001) and a decrease in group II (82% to 73%, p < 0.01). Bidirectional CPA facilitates ventricular volume unloading and promotes regression of left ventricular mass in younger children (< 3 years) in preparation for a Fontan operation. In contrast, bidirectional CPA is of questionable value in older children as a staging procedure for Fontan palliation.