Mehdi Hakimi

Pediatric cardiac surgical ECMO: Multivariate analysis of risk factors for hospital death

BACKGROUND Extracorporeal membrane oxygenation (ECMO) has emerged as an effective technique for the mechanical support of many pediatric postcardiotomy patients with medically refractory cardiac failure. METHODS We retrospectively reviewed the records of 73 pediatric patients with congenital heart disease who were placed on ECMO support between August 1984 and February 1994. The patients were divided into groups defined by the timing of ECMO cannulation relative to the time of operation. Group 1 patients (n = 7, 9.6%) were placed on ECMO preoperatively. Group 2 patients (n = 66, 90.4%) were a heterogeneous population placed on ECMO at any interval after cardiac repair. Subgroup 2A consisted of patients (n = 17, 25.8%) who could not be weaned from cardiopulmonary bypass and were converted directly to ECMO support immediately after repair. Subgroup 2B patients (n = 49, 74.2%) were cannulated postoperatively after an initial period of clinical stability. RESULTS Hospital survival for all study patients (42/73) and for group 2 patients (38/66) was 58%. Only 4 group 2A patients (23.5%) survived their hospitalization compared with 34 group 2B patients (69.4%) (p = 0.001). Multivariate analysis identified elevated right atrial pressure after ECMO decannulation (p = 0.049) and, possibly, membership in group 2A (p = 0.061) as independent risk factors for hospital death. CONCLUSIONS Extracorporeal membrane oxygenation is most effective in salvaging pediatric cardiac surgical patients who demonstrate medically refractory hemodynamic deterioration at some interval after being successfully weaned from cardiopulmonary bypass. The right atrial pressure after extracorporeal membrane oxygenation decannulation is an independent predictor of hospital death.

Coronary Sinus Ostial Atresia With Persistent Left Superior Vena Cava

BACKGROUND Atresia of the coronary sinus orifice with a persistent left superior vena cava is an intrinsically benign cardiac anomaly with important surgical implications. METHODS THe medical records of 5 patients with atresia of the coronary sinus orifice with a persistent left superior vena cava were reviewed retrospectively, and a computer search of the world literature describing this cardiac malformation was undertaken. RESULTS The 5 patients ranged in age from 9 months to 5 years. In 2, the diagnosis was made preoperatively by angiocardiography, and in 3, the abnormality was found incidentally at the time of cardiotomy for repair of associated congenital heart disease. Four of the 5 patients underwent repair of associated cardiac lesions. During operation, care was taken to avoid disruption of left superior vena cava flow to prevent coronary venous obstruction. All patients survived and are doing well at follow-up. CONCLUSIONS Atresia of the coronary sinus orifice with persistent left superior vena cava is, in itself, a benign anomaly without physiologic consequence. However, the recognition of this lesion during repair of associated cardiac lesions is of vital importance to the cardiac surgeon. Interruption of this sole route of coronary venous drainage can potentially lead to myocardial ischemia and necrosis.

Chronic performance of steroid-eluting epicardial leads in a growing pediatric population: a 10-year comparison.

Patient size and congenital heart defects complicate pacemaker therapy in children favoring an initial epicardial approach. Steroid‐eluting (SE) epicardial (EPI) leads maintain stable, low pacing thresholds in the short‐term when compared to the nonsteroid (NSE) epicardial (EPI) leads. The purpose of this study was to evaluate chronic, 10‐year performance of SE leads in growing children compared with NSE EPI leads implanted during the same time interval. From 1990 to 2000, 35 patients (age 1 month to 18 year, median 3 years), 28 with and 7 without congenital heart disease (CHD) received 51 SE leads: 27 ventricular and 24 atrial. NSE leads were implanted in 27 patients (age 1–28 years, median 8 years), 24 with and 3 without CHD: 27 ventricular and 1 atrial. Pacing lead threshold, impedance, and energy were measured at implant and during a 10‐year follow‐up. Unpaired t‐test showed that impedance remained stable for all leads with lower mean values for the SE (376 ± 55 vs 443 ± 109 Ω) (P = NS) . The mean energy requirement for SE leads at 10 years (1.2 ± 0.9 μJ) was significantly lower than for NSE (4.4 ± 5.5 μJ) (P < 0.05) . At 2.5‐V output, chronic thresholds for SE leads did not significantly differ from implant values for atrial (0.08 vs 0.09 ms) or ventricular (0.08 vs 0.08 ms) sites. There were no differences in SE lead performances among patients with or without CHD. Fracture or dislodgement occurred in two SE (4%) and four NSE (14%) leads. SE outperform NSE EPI leads and show stable, chronic low thresholds over time in all growing children. (PACE 2003; 26[Pt. I]:1467–1471)

Congenital coronary artery fistulae: a review of 18 cases with special emphasis on spontaneous closure.

SummaryBetween 1972 and 1990, 18 patients (median age 3 years, range 0.1–14 years) with coronary artery fistulae (CAF) were seen at this institution. Of the 16 patients without associated heart defects, two patients presented with congestive heart failure and the remaining 14 were asymptomatic. Fifteen patients had normal orgin of two coronary arteries. Two patients has atresia of the proximal right coronary artery and, in one patient, the right coronary artery originated from the left main coronary artery. The QP/QS ranged between 1.0 and 2.8, with a mean of 1.4. Fifteen patients underwent operative closure without any deaths. One patient is being followed medically at present. Two patients showed spontaneous clinical improvement of CAF (complete closure in one and near complete in the other) and remained asymptomatic during a decade of follow-up. Review of the literature suggests operative closure of symptomatic and asymptomatic small CAF during childhood. However, the natural history of minute CAF remains unclear. In addition, symptoms from CAF may spontaneously improve with time.

Aortic root dilation after the Ross procedure.

This study evaluated changes in neoaortic root geometry in patients who underwent the Ross procedure. Serial postoperative echocardiographic measurements of the neoaortic root indexed to the square root of body surface area (centimeters divided by meters) were obtained from 30 patients (age range 3.1 to 31.4 years) and compared with paired preoperative and immediate postoperative values. Normal aortic root diameter Z scores were derived from root dimensions obtained from 217 healthy controls. Compared with preoperative values, an immediate stretch of the neoaortic versus pulmonary root (annulus and sinuses of valsalva) was observed at a mean follow-up period of 1 week. Additional aortic annular dilation from baseline prehospital discharge values was observed at 2 to 12 months (baseline vs follow-up annulus Z score: 1.4 vs 2.6, p <0.01, n = 16) and at 16 to 33 months follow-up (0.8 vs 2.0, p <0.05, n = 12). In a similar fashion, there was additional enlargement of the aortic sinus from its stretched state at hospital discharge at 2 to 12 months (baseline vs follow-up sinus Z score: 2.0 vs 3.3, p <0.01, n = 17) and at 16 to 33 months (1.7 vs 3.0, p <0.01, n = 13). There were no differences in root size between 2 to 12 and 16 to 33 months after surgery. There was a decrease in left ventricular size with no alteration in blood pressure or degree of aortic valve regurgitation. Thus, aortic root dilation occurs up to the first year after the Ross procedure but does not appear to progress beyond this time.

STEROID-ELUTING EPICARDIAL PACING ELECTRODES : SIX YEAR EXPERIENCE OF PACING THRESHOLDS IN A GROWING PEDIATRIC POPULATION

Indications for pacemaker implantation in the pediatric population often include sinus or atrioventricular node dysfunction following surgery for congenital heart defects. However, patient size, cardiac defects, and vascular and valvular concerns may limit transvenous lead utilization. Since the epicardial surface of these patients often exhibits variable degrees of fibrosis from scar tissue formation or pericardial adhesions, chronic low output (2.5/1.6 V, 0.3 ms) epicardial pacing from implant is not currently recommended in children due to frequent threshold changes and electrode exit block. As a result, pacing in children is often viewed as a less efficient system than in adults. The addition of steroid combined with newer low threshold electrode designs however stabilizes the electrode‐tissue interface and eliminates postimplant changes seen with standard smooth surface electrodes potentially permitting efficient chronic pacemaker application to all patient ages. The stability of chronic low output epicardial pacing with steroid‐eluting electrodes was prospectively studied in 22 patients (ages 2 days‐18.5 years, median 3.5 years) for up to 6 years. Chronic pulse width thresholds were compared according to implant site and association of prior cardiac surgery. A total of 26 pacing leads were implanted. The acute implant mean pulse width threshold (2.5 V) for all the electrodes studied was 0.10 ms ± 0.05 ms. Stable low thresholds were maintained for up to 6 years without significant variation from implant. Mean ventricular pulse width thresholds (0.12 ms ± 0.05 ms) were significantly higher (P < 0.001) than atrial thresholds (0.06 ms ± 0.03 ms) at implant and throughout the study period. The thresholds in the patients following cardiac surgery were comparable to those without previous cardiac surgery (P = NS). Stable low thresholds may be chronically maintatined for up to 6 years for epicardial steroid‐eluting electrodes irrespective of pacing site or associated cardiac surgery.

Coil Occlusion Versus Conventional Surgical Closure of Patent Ductus Arteriosus

This retrospective cohort study evaluated the clinical outcome and cost-effectiveness of 2 treatment strategies for children with an isolated restrictive patent ductus arteriosus. Results indicate a superior cost-effectiveness of transcatheter coil occlusion compared with conventional surgery for these patients.

Risk factors for failure of aortic valvuloplasty in aortic insufficiency with ventricular septal defect

BACKGROUND Aortic insufficiency (AI) associated with ventricular septal defect (VSD) is often repaired using a modification of Truslers aortic valvuloplasty technique. The purpose of this study was to identify the risk factors for failure of aortic valve (AV) repair in patients who underwent repair of associated VSD. METHODS A univariate analysis was performed in this retrospective study to identify the possible risk factors for failure of the repair resulting in the need for AV replacement (AVR). RESULTS The study included 24 patients, 15 (62%) boys and 9 (38%) girls, with a mean age of 9.1 +/- 1.2 (SEM) years. The VSD was perimembranous in 15 (62%) and subarterial in 9 (38%). The prolapsed aortic cusp was the right in 13 (54%), the noncoronary in 6 (25%), and both in 5 (21%). Plication was performed at one end of the free edge of the prolapsed cusp(s) in 12 (50%) and at more than one end in 12 (50%) of the patients. The VSD was closed by use of a patch in 21 (88%) and by direct suture closure in 3 (12%). At the mean follow up of 7.3 +/- 1.3 years, the degree of AI was none in 6 (25%), trivial in 5 (21%), mild in 9 (38%), moderate in 1 (4%), and severe in 3 (12%). The 15-year actuarial freedom from reoperation was 81% +/- 19% (95% confidence limit). By univariate analysis, the possible risk factors for AV repair failure were the degree of AI at hospital discharge (p = 0.004), direct closure of the VSD (p = 0.061), smaller size of the VSD (p = 0.081), and plication of more than one end of the prolapsed cusp(s) (p = 0.095). CONCLUSIONS Truslers AV repair is an effective and durable technique for the surgical treatment of patients with VSD-AI syndrome. The adequacy of the initial repair is the most important determinant of the long-term results.

Bidirectional cavopulmonary anastomosis with intracardiac repair.

BACKGROUND Patients with hypoplasia of the right ventricle and tricuspid valve have historically undergone a total cavopulmonary connection or a two-ventricle repair with atrial fenestration. METHODS We reviewed our experience with 9 patients with hypoplasia of the right ventricle and tricuspid valve who underwent a bidirectional cavopulmonary anastomosis with intracardiac repair. Patient diagnoses included pulmonary atresia with intact ventricular septum (n = 3); hypoplastic right ventricle and tricuspid valve with atrial septal defect, ventricular septal defect, and right ventricular outflow tract obstruction (n = 3); unbalanced atrioventricular canal defect (n = 1); inlet ventricular septal defect with coarctation (n = 1); and tricuspid stenosis with atrial septal defect (n = 1). RESULTS The median age at operation was 36 months. There was hypoplasia of the right ventricle and tricuspid valve in all patients. The tricuspid valve measured 56.5% of normal (range, 43.6% to 70.4%) by echocardiography, and the median ratio of the tricuspid valve to the mitral valve was 0.67 (range, 0.54 to 0.82). At operation, the median tricuspid valve annulus diameter was 65.6% of published autopsy normals (range, 57.8% to 78.5%) with a median Z value of -3.8 (range, -6.6 to -2.1). All patients survived operation. At a median follow-up of 16 months, 5 patients are asymptomatic, and 2 have occasional early-morning periorbital edema. Two patients are on a regimen of diuretics, 1 of whom is also taking an unloading agent. The patient with unbalanced atrioventricular canal died suddenly at home 6 months postoperatively. CONCLUSIONS Bidirectional cavopulmonary anastomosis with intracardiac repair may avoid the long-term complications associated with the Fontan modifications and eliminates the need of atrial fenestration in most instances. This operation should be considered for select patients with hypoplasia of the right ventricle and tricuspid valve.

Primary pulmonary artery sarcoma in two children

SummaryThe clinical and pathological features of primary pulmonary artery sarcoma in two children are reported. The first patient presented with right ventricular outflow obstruction and underwent successful surgical resection of his tumor. The second patient developed cardiac arrest following a relatively short period of symptoms of right heart failure and could not be revived. The pathological diagnosis in both patients was hemangiopericytoma. To the best of our knowledge, primary pulmonary artery sarcoma in children has not been previously reported.