Anthony F. Rossi

Estimation of Oxygen Delivery in Newborns With a Univentricular Circulation

BACKGROUND The management of neonates with complex congenital anomalies depends on careful interpretation of arterial blood gas values. Improved interpretation of these oxygen parameters may allow clinicians to avoid unexpected cardiovascular events. This study examined whether systemic oxygen delivery (DO2) can be maximized by the use of indices derived from oxygen saturation measurements in neonates with hypoplastic left heart syndrome. METHODS AND RESULTS For the single-ventricle heart with both circulations in parallel, we used a previously developed computer simulation to obtain DO2 as a function of systemic arterial (SaO2) and venous (SvO2) oxygen saturation, arteriovenous oxygen difference (Sa-vO2), or pulmonary-to-systemic flow ratio (Qp/Qs). We also examined the oxygen excess factor, SaO2/Sa-vO2 (Omega). We found that (1) slight increases in SaO2 may be associated with large decreases in DO2. (2) Low values for SvO2 indicate low values for DO2. (3) Curves for Sa-vO2 and Qp/Qs are redundant in the data provided. (Qp/Qs, however, provides these data in more physiologically relevant terms.) (4) High values for Qp/Qs (>4) are associated with low DO2. (5) Estimating Qp/Qs from oxygen saturation measurements may result in errors when pulmonary venous oxygen saturation is not available. (6) Maximizing DO2 is extremely difficult using SaO2, SvO2, and Qp/Qs. (7) A linear relationship exists between Omega and DO2, and this linear relationship is not altered by changes in cardiac output. CONCLUSIONS Patients with low SvO2 values require attention. Ideally, after reducing Qp/Qs to <1.5, Omega might be a better index to guide further therapy and maximize DO2. Interventions that increased Omega would be considered beneficial, whereas interventions that decreased Omega would be considered detrimental.

Care Models and Associated Outcomes in Congenital Heart Surgery

OBJECTIVE: Recently, there has been a shift toward care of children undergoing heart surgery in dedicated pediatric cardiac intensive care units (CICU). The impact of this trend on patient outcomes is unclear. We evaluated postoperative outcomes associated with a CICU versus other ICU models. PATIENTS AND METHODS: Society of Thoracic Surgeons Congenital Heart Surgery Database participants (2007–2009) who completed an ICU survey were included. In multivariable analysis, we evaluated outcomes associated with a CICU versus other ICUs, adjusting for center volume, patient factors, and Society of Thoracic Surgeons–European Association for Cardiothoracic Surgery surgical risk category. RESULTS: A total of 20 922 patients (47 centers; 25 with a CICU) were included. Overall unadjusted mortality was 3.8%, median length of stay was 6 days (interquartile range: 4–13), and 21% had 1 or more complications. In multivariable analysis, there was no difference in mortality comparing CICUs versus other ICUs (odds ratio: 0.88 [95% confidence interval: 0.65–1.19]). In stratified analysis, CICUs were associated with lower mortality only among those in Society of Thoracic Surgeons–European Association for Cardiothoracic Surgery category 3 (odds ratio: 0.47 [95% confidence interval: 0.25–0.86]), primarily related to atrioventricular canal repair and arterial switch operation. There was no difference in length of stay or complications overall or in stratified analysis. CONCLUSIONS: We were not able to detect a difference in postoperative morbidity or mortality associated with the presence of a dedicated CICU for children undergoing heart surgery. There may be a survival benefit in certain subgroups .

Variation in Models of Care Delivery for Children Undergoing Congenital Heart Surgery in the United States

Limited data are available regarding contemporary models of care delivery for patients undergoing congenital heart surgery. The purpose of this survey was to evaluate current US practice patterns in this patient population. Cross-sectional evaluation of US centers caring for patients undergoing congenital heart surgery was performed using an Internet-based survey. Data regarding postoperative care were collected and described overall and were compared in centers with a pediatric intensive care unit (PICU) versus dedicated pediatric cardiac intensive care unit (CICU). A total of 94 (77%) of the estimated 122 US centers performing congenital heart surgery participated in the survey. The majority (79%) of centers were affiliated with a university. Approximately half were located in a free-standing children’s hospital and half in a children’s hospital in a hospital. Fifty-five percent provided care in a PICU versus a CICU. A combination of cardiologists and/or critical care physicians made up the largest proportion of physicians primarily responsible for postoperative care. Trainee involvement most often included critical care fellows (53%), pediatric residents (53%), and cardiology fellows (47%). Many centers (76%) also used physician extenders. In centers with a CICU, there was greater involvement of cardiologists and physicians with dual training (cardiology and critical care), fellows versus residents, and physician extenders. Results of this survey demonstrate variation in current models of care delivery used in patients undergoing congenital heart surgery in the United States. Further study is necessary to evaluate the implications of this variability on quality of care and patient outcomes.

Transforming patient and family access to medical information: utilisation patterns of a patient-accessible electronic health record.

OBJECTIVE The purpose of this study was to evaluate the utilisation of a web-based multimedia patient-accessible electronic health record, for patients with congenital cardiac disease. PATIENTS AND METHODS This was a prospective analysis of patients undergoing congenital cardiac surgery at a single institution from 1 September, 2006 to 1 February, 2009. After meetings with hospital administration, physicians, nurses, and patients, we configured a subset of the cardiac programs web-based clinical electronic health record for patient and family access. The Electronic Health Record continuously measured frequency and time of logins, logins during and between hospitalisations, and page views by type (imaging versus textual data). RESULTS Of the first 270 patients offered access to the system, 252 became users (93% adoption rate). System uptime was 99.9%, and no security breaches were reported. Users accessed the system more often while the patients were in hospital (67% of total logins) than after discharge (33% of total logins). The maximum number of logins by a family was 440, and the minimum was 1. The average number of logins per family was 25. Imaging data were viewed significantly more frequently than textual data (p 0.001). A total of 12 patients died during the study period and 11 members of their families continued to access their Electronic Health Records after the date of death. CONCLUSIONS A web-based Patient Accessible Electronic Health Record was designed for patients with congenital cardiac disease. The adoption rate was high, and utilisation patterns suggest that the Electronic Health Record could become a useful tool for health information exchange.

New approach to interstage care for palliated high-risk patients with congenital heart disease

OBJECTIVE Home surveillance monitoring might identify patients at risk for interstage death after stage 1 palliation for hypoplastic left heart syndrome. We sought to identify the effect that a high-risk program might have on interstage mortality and identification of residual/recurrent lesions after neonatal palliative operations. METHODS Between January 2006 to January 2010, newborns after stage 1 palliation for hypoplastic left heart syndrome or shunt placement were invited to participate in our high-risk program. Patients enrolled in our high-risk program comprise the study group. Patients who had similar operations between January 2002 and December 2005 comprise the control group. Comparisons are made between the 2 groups with respect to interstage mortality and the frequency and timing of interstage admissions requiring medical, catheter, or surgical treatment. RESULTS Seventy-two patients met the criteria for our high-risk program. Fifty-nine (82%) of 72 patients were enrolled. Among 19 patients with hypoplastic left heart syndrome in our high-risk program, outpatient interstage mortality was zero. Outpatient interstage mortality for the 36 control subjects with hypoplastic left heart syndrome was 6%. Among 40 patients with shunts in the study group, there was 1 outpatient interstage death compared with 4 (6%) deaths in 68 subjects in the control group. Significant residual/recurrent lesions were identified with similar frequency between the 2 groups. However, after shunt operations, these lesions were detected and treated at significantly younger mean ages for patients followed in the high-risk program (P < .005). CONCLUSIONS Initiation of a high-risk program might decrease interstage mortality after high-risk neonatal palliative operations. Such an approach might contribute to earlier detection of significant residual/recurrent lesions amenable to therapy.

Midterm Results for Collaborative Treatment of Pulmonary Atresia With Intact Ventricular Septum

BACKGROUND We report a single-institution experience using a collaborative surgical and catheter-based approach to the initial treatment of pulmonary atresia with intact ventricular septum. METHODS A retrospective review was conducted of all neonates admitted with pulmonary atresia with intact ventricular septum from 1996 to March 2007. RESULTS We identified 24 patients with a mean age at first intervention of 4.5 days with mean follow-up of 6.05 years (range, 1.9 to 12.7 years). Initial palliation was determined by right ventricular size, morphology, and presence or absence of right ventricular-dependent coronary circulation. Initial catheter-based pulmonary valve perforation and valvuloplasty was performed in 41.7% (10 of 24 patients; group A), and 58.3% (14 of 24 patients) had an initial systemic-to-pulmonary artery shunt (group B). Tricuspid valve size was significantly smaller in group B (median z-score, -0.52 group A versus -2.40 group B; p < 0.001). Placement of a shunt after valvuloplasty in group A was required in 70.0% (7 of 10 patients). There was no mortality in group A, and 70.0% (7 of 10 patients) are in a two-ventricle pathway and 30.0% (3 of 10 patients) are in a 1.5-ventricle pathway. Group B had mortality of 14.3% (2 of 14 patients), both within 5 days of surgery. All group B patients remain in a single-ventricle pathway. Overall survival is 91.7% (22 of 24 patients). CONCLUSIONS An individualized approach to this complex lesion has good results. If the right ventricle can be safely decompressed and appears usable, the need for a shunt after valvuloplasty does not preclude two-ventricle (or 1.5-ventricle) repair. Anatomy mandating a shunt as initial palliation has substantial early mortality.

Congenital cardiac surgery without routine placement of wires for temporary pacing.

OBJECTIVE Temporary pacing wires have been associated with serious postoperative complications. Recommendations for their routine use after open heart surgery are decades old, and may not reflect current surgical techniques and outcomes. METHODS The electronic web-enabled medical records of all patients undergoing congenital cardiac surgery from February, 2002, through December, 2005, were reviewed, excluding patients undergoing implantation of pacemakers as a primary procedure, or those undergoing ligation of a patent arterial duct. RESULTS There were 1193 surgical procedures performed, 1041 with cardiopulmonary bypass. Median age of the patients was 5.8 months, with a range from 0 days to 54 years, weighing 6.2 kilograms, with a range from 1 to 114 kilograms. Mortality prior to discharge was 2.5%, and median postoperative stay was 6 days. No deaths were attributed to arrhythmias. Temporary pacing wires were placed 14 times (1.2%). Indications for placement included sinus nodal dysfunction in 8 patients, preoperative in 4 and intraoperative in 4, high degree atrioventricular block in 4 patients, and intraoperative atrial flutter in 2 patients. Of these patients, 4 (0.3%) eventually underwent permanent implantation of a pacemaker, 2 for persistent sinus nodal dysfunction, and 2 for persistent atrioventricular block. Postoperative junctional ectopic tachycardia requiring antiarrhythmic therapy occurred in 9 patients (0.8%). All recovered without incident, and none were treated with temporary pacing. CONCLUSIONS The diminished risk of unexpected postoperative arrhythmias in the current era alleviates the necessity for routine placement of temporary pacing wires. Those institutions with experienced surgical and cardiac critical care teams may be able to predict the need for temporary pacing wires preoperatively or intraoperatively.

Radiofrequency Ablation of Pediatric AV Nodal Reentrant Tachycardia during the Ice Age: A Single Center Experience in the Cryoablation Era

Background: Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) has proven to be an effective therapy in the pediatric population. However, concerns of inadvertent permanent AV nodal block have resulted in many pediatric programs adopting cryoablation as their primary ablation approach for AVNRT.

Creation of Partial Fascicular Block: An Approach to Ablation of Idiopathic Left Ventricular Tachycardia in the Pediatric Population

Catheter ablation of idiopathic left ventricular tachycardia in the pediatric population remains challenging. A recent multicenter study reported limited success with 14% not undergoing ablation due to inability to induce ventricular tachycardia (VT) or blood pressure instability during tachycardia. Creating complete or partial fascicular block with radiofrequency catheter ablation is a technique that may eliminate VT. This approach is performed during sinus rhythm, enabling atrioventricular conduction monitoring and maintaining stable hemodynamics. Importantly, induction of VT is not necessary for mapping or assessing efficacy of the procedure.

The fenestrated Kawashima operation for single ventricle with interrupted inferior vena cava

An 8-month-old boy with double outlet right ventricle with hypoplastic left ventricle, heterotaxy, left atrial isomerism, bilateral superior vena cavae without bridging vein, and interruption of the inferior vena cava with azygous continuation to the left superior cava underwent a bilateral bidirectional cavopulmonary anastomosis. A calibrated 3-mm connection between the right pulmonary artery and the common atrium was constructed with the proximal right superior vena cava to allow right to left shunting, analogous to a fenestration in a Fontan operation. We hypothesize that in small young patients undergoing the Kawashima operation a fenestration may improve postoperative hemodynamics.