Mark G. Hazekamp

Preoperative Thresholds for Pulmonary Valve Replacement in Patients With Corrected Tetralogy of Fallot Using Cardiovascular Magnetic Resonance

Background— To facilitate the optimal timing of pulmonary valve replacement, we analyzed preoperative thresholds of right ventricular (RV) volumes above which no decrease or normalization of RV size takes place after surgery. Methods and Results— Between 1993 and 2006, 71 adult patients with corrected tetralogy of Fallot underwent pulmonary valve replacement in a nationwide, prospective follow-up study. Patients were evaluated with cardiovascular magnetic resonance both preoperatively and postoperatively. Changes in RV volumes were expressed as relative change from baseline. RV volumes decreased with a mean of 28%. RV ejection fraction did not change significantly after surgery (from 42±10% to 43±10%; P=0.34). Concomitant RV outflow tract reduction resulted in a 25% larger decrease of RV volumes. After correction for surgical RV outflow tract reduction, higher preoperative RV volumes (mL/m2) were independently associated with a larger decrease of RV volumes (RV end-diastolic volume: &bgr;=0.41; P<0.001). Receiver operating characteristic analysis revealed a cutoff value of 160 mL/m2 for normalization of RV end-diastolic volume or 82 mL/m2 for RV end-systolic volume. Conclusions— Overall, we could not find a threshold above which RV volumes did not decrease after surgery. Preoperative RV volumes were independently associated with RV remodeling and also when corrected for a surgical reduction of the RV outflow tract. However, normalization could be achieved when preoperative RV end-diastolic volume was <160 mL/m2 or RV end-systolic volume was <82 mL/m2.

Decellularization of rat aortic valve allografts reduces leaflet destruction and extracellular matrix remodeling.

OBJECTIVES Decellularization of aortic valve allografts in advance of transplantation is a promising approach to overcome immune-induced early graft failure. In this study the effects of in vitro cell extraction on extracellular matrix molecules and in vivo remodeling of decellularized aortic valves were investigated in a heterotopic aortic valve rat implantation model. METHODS Rat aortic valve conduits were decellularized by a 2-step detergent-enzymatic extraction method involving sodium dodecyl sulfate in combination with RNase and DNase. Cellular and acellular allogeneic (2x, n = 4) and syngeneic valve grafts (2x, n = 3) were grafted infrarenally into the descending aorta for 21 days. Immunohistochemical techniques were used to study extracellular matrix constitution (elastin, collagen, fibronectin, and chondroitin sulfate) and cellular infiltration. RESULTS The decellularization procedure resulted in a complete loss of all cellular structures from the entire valve conduit with minimal damage to the extracellular matrix. All transplanted cellular allografts became deformed, swollen, and acellular with major changes in extracellular matrix structure. The transplanted decellularized allografts, however, retained normal preserved valve leaflets comparable to transplanted cellular and acellular syngeneic grafts. With the exception of cellular syngeneic grafts, all other grafts showed retrovalvular thrombi. CONCLUSIONS Damage to the valves caused by decellularization technique is much less than the damage caused by the recipients immune response. In vitro removal of viable cells in (cryopreserved) homografts may decrease graft failure. Seeding with autologous or major histocompatibility complex-matched donor endothelial cells will be necessary to diminish damage induced by an absent blood-tissue barrier.

Development of human plasmacytoid dendritic cells depends on the combined action of the basic helix‐loop‐helix factor E2‐2 and the Ets factor Spi‐B

Plasmacytoid dendritic cells (pDC) are central players in the innate and adaptive immune response against viral infections. The molecular mechanism that underlies pDC development from progenitor cells is only beginning to be elucidated. Previously, we reported that the Ets factor Spi‐B and the inhibitors of DNA binding protein 2 (Id2) or Id3, which antagonize E‐protein activity, are crucially involved in promoting or impairing pDC development, respectively. Here we show that the basic helix‐loop‐helix protein E2‐2 is predominantly expressed in pDC, but not in their progenitor cells or conventional DC. Forced expression of E2‐2 in progenitor cells stimulated pDC development. Conversely, inhibition of E2‐2 expression by RNA interference impaired the generation of pDC suggesting a key role of E2‐2 in development of these cells. Notably, Spi‐B was unable to overcome the Id2 enforced block in pDC development and moreover Spi‐B transduced pDC expressed reduced Id2 levels. This might indicate that Spi‐B contributes to pDC development by promoting E2‐2 activity. Consistent with notion, simultaneous overexpression of E2‐2 and Spi‐B in progenitor cells further stimulated pDC development. Together our results provide additional insight into the transcriptional network controlling pDC development as evidenced by the joint venture of E2‐2 and Spi‐B.

Pulmonary valve insertion late after repair of Fallot's tetralogy

Objectives: To analyze the results of pulmonary valve insertion late after initial repair of Fallot’s tetralogy. Pulmonary insufficiency (PI) after correction of Fallot’s tetralogy is usually well tolerated in the short term, but is associated with symptomatic right ventricular dilatation and an increased risk of ventricular arrhythmias over longer periods of time. Methods: From 1993 to July 2000, 51 patients were reoperated for PI at a mean age of 25.7 ^ 11.9 years. The mean age at initial repair was 6.4 ^ 7.2 years. Patients with a conduit inserted at initial operation, with absent pulmonary valve syndrome or with a more than moderate ventricular septal defect at reoperation were excluded from the study. A cryopreserved pulmonary (96%) or aortic (4%) homograft was implanted in the orthotopic position with the use of cardiopulmonary bypass 19.3 ^ 9.1 years (2.7‐40.3 years) after initial correction. Preoperative symptoms (New York Heart Association, NYHA class), degree of PI (echo-Doppler, MRI), right ventricular dimensions (MRI) and QRS duration were compared to findings at last follow-up. Results: Follow-up is complete and had a mean duration of 1.7 ^ 1.4 years. Hospital mortality was 2%. No serious morbidity occurred. Severe PI was present preoperatively in all patients. At last follow-up echo-Doppler studies showed PI to be absent or trivial in 96% and mild in 4% of patients. In 13 patients MRI studies were performed both pre- and postoperatively: in this group PI was reduced from a mean of 48 to 4%. After 6 months NYHA capacity class had improved significantly from 2.3 ^ 0.6 to 1.4 ^ 0.5. After 1 year end-diastolic and end-systolic right ventricular volumes were reduced significantly. Right ventricular ejection fraction and QRS duration remained unchanged. Conclusions: PI late after correction of Fallot’s tetralogy may lead to serious symptomatic right ventricle dilatation. After pulmonary homograft insertion right ventricular dimensions decrease rapidly and functional improvement is observed in almost all patients. q 2001 Elsevier Science B.V. All rights reserved.

Scimitar Syndrome A European Congenital Heart Surgeons Association (ECHSA) Multicentric Study

Background— Scimitar syndrome is a rare congenital heart disease. To evaluate the surgical results, we embarked on the European Congenital Heart Surgeons Association (ECHSA) multicentric study. Methods and Results— From January 1997 to December 2007, we collected data on 68 patients who underwent surgery for scimitar syndrome. Primary outcomes included hospital mortality and the efficacy of repair at follow-up. Median age at surgery was 1.4 years (interquartile range, 0.46 to 7.92 years). Forty-four patients (64%) presented with symptoms. Surgical repair included intraatrial baffle in 38 patients (56%; group 1) and reimplantation of the scimitar vein onto the left atrium in 21 patients (31%; group 2). Eight patients underwent right pneumectomy, and 1 had a right lower lobe lobectomy (group 3). Four patients died in hospital (5.9%; 1 patient in group 1, 2.6%; 3 patients in group 3, 33%). Median follow-up time was 4.5 years. There were 2 late deaths (3.1%) resulting from severe pulmonary arterial hypertension. Freedom from scimitar drainage stenosis at 13 years was 83.8% in group 1 and 85.8% in group 2. Four patients in group 1 were reoperated, and 3 patients (2 in group 1 [6%] and 1 in group 2 [4.8%]) required balloon dilation/stenting for scimitar drainage stenosis. Conclusions— The surgical treatment of this rare syndrome is safe and effective. The majority of patients were asymptomatic at the follow-up control. There were a relatively high incidence of residual scimitar drainage stenosis that is similar between the 2 reported corrective surgical techniques used. # Clinical Perspective {#article-title-44}Background— Scimitar syndrome is a rare congenital heart disease. To evaluate the surgical results, we embarked on the European Congenital Heart Surgeons Association (ECHSA) multicentric study. Methods and Results— From January 1997 to December 2007, we collected data on 68 patients who underwent surgery for scimitar syndrome. Primary outcomes included hospital mortality and the efficacy of repair at follow-up. Median age at surgery was 1.4 years (interquartile range, 0.46 to 7.92 years). Forty-four patients (64%) presented with symptoms. Surgical repair included intraatrial baffle in 38 patients (56%; group 1) and reimplantation of the scimitar vein onto the left atrium in 21 patients (31%; group 2). Eight patients underwent right pneumectomy, and 1 had a right lower lobe lobectomy (group 3). Four patients died in hospital (5.9%; 1 patient in group 1, 2.6%; 3 patients in group 3, 33%). Median follow-up time was 4.5 years. There were 2 late deaths (3.1%) resulting from severe pulmonary arterial hypertension. Freedom from scimitar drainage stenosis at 13 years was 83.8% in group 1 and 85.8% in group 2. Four patients in group 1 were reoperated, and 3 patients (2 in group 1 [6%] and 1 in group 2 [4.8%]) required balloon dilation/stenting for scimitar drainage stenosis. Conclusions— The surgical treatment of this rare syndrome is safe and effective. The majority of patients were asymptomatic at the follow-up control. There were a relatively high incidence of residual scimitar drainage stenosis that is similar between the 2 reported corrective surgical techniques used.

Acute Renal Insufficiency and Renal Replacement Therapy After Pediatric Cardiopulmonary Bypass Surgery

Abstract. The aim of the study was to investigate renal function and renal replacement therapy after cardiopulmonary bypass surgery in children. Patient characteristics (sex, age, diagnosis), operation type, and death were listed. The study was performed retrospectively using serum creatinine level before, and peak values after, cardiopulmonary bypass surgery for assessment of renal function. Of the children on renal replacement therapy, indication, efficacy, and complications were recorded. In a 5-year period, 1075 children had cardiopulmonary bypass surgery at the Department of Cardiothoracic Surgery at Leiden University Medical Center and Academic Medical Center of Amsterdam. One-hundred eighty (17%) patients developed acute renal insufficiency. Twenty-five (2.3%) patients required renal replacement therapy. Peritoneal dialysis is a safe and effective treatment for children after cardiopulmonary bypass surgery. However, 15 (60%) of 25 children on renal replacement therapy died of nonrenal causes. In 9 out of 10 surviving children, renal function was normal at time of discharge from hospital. Acute renal insufficiency is a frequent complication after open-heart surgery, although renal replacement therapy was infrequently necessary. Peritoneal dialysis is a safe and effective therapeutic measure for children after cardiac bypass surgery.

Modified ultrafiltration after cardiopulmonary bypass in pediatric cardiac surgery

BACKGROUND Cardiopulmonary bypass in children results in considerable water retention, especially in neonates and small infants. Dilution of plasma proteins increases water loss into the extravascular compartments. Excessive total body water may prolong ventilatory support and may contribute to a prolongation of intensive care convalescence. After discontinuation of cardiopulmonary bypass, modified ultrafiltration can be used to withdraw plasma water from the total circulating volume. METHODS This retrospective study included 198 pediatric patients who underwent cardiac operations in the period from September 1991 to November 1994. Two groups were compared: 99 patients without ultrafiltration and 99 patients receiving modified ultrafiltration. The following indices were analyzed: cardiopulmonary bypass prime volume, transfused blood volume during and after the operation, postoperative chest drain loss, and hemoglobin and hematocrit levels before, during, and after the procedure. RESULTS Modified ultrafiltration resulted in a significant increase in hemoglobin and hematocrit levels and a significantly lower amount of transfused blood. Mean postoperative chest drain loss was significantly less in the patients who underwent modified ultrafiltration. CONCLUSIONS Modified ultrafiltration decreases blood transfusion requirements and chest drain loss after pediatric cardiac surgical procedures.

Surgery in Adults With Congenital Heart Disease

Background— A significant proportion of patients with congenital heart disease require surgery in adulthood. We aimed to give an overview of the prevalence, distribution, and outcome of cardiovascular surgery for congenital heart disease. We specifically questioned whether the effects of surgical treatment on subsequent long-term survival depend on sex. Methods and Results— From the Dutch Congenital Corvitia (CONCOR) registry for adults with congenital heart disease, we identified 10 300 patients; their median age was 33.1 years. Logistic and Cox regression models were used to assess the association of surgery in adulthood with sex and with long-term survival. In total, 2015 patients (20%) underwent surgery for congenital heart disease in adulthood during a median follow-up period of 15.1 years; in 812 patients (40%), it was a reoperation. Overall, both first operations and reoperations in adulthood were performed significantly more often in men compared with women (adjusted odds ratio=1.4 [95% confidence interval, 1.2–1.6] and 1.2 [95% confidence interval, 1.0–1.4], respectively). Patients with their third and fourth or more surgery in adulthood had a 2- and 3-times-higher risk of death compared with patients never operated on (adjusted hazard ratio=1.9 [95% confidence interval, 1.0–3.6] and 2.7 [95% confidence interval, 1.1–6.3], respectively). Men with a reoperation in adulthood had a 2-times-higher risk of death than women (adjusted hazard ratio=1.9; 95% confidence interval, 1.0–3.5). Conclusions— Of predominantly young adults with congenital heart disease, one fifth required cardiovascular surgery during a 15-year period; in 40%, the surgery was a reoperation. Men with congenital heart disease have a higher chance of undergoing surgery in adulthood and have a consistently worse long-term survival after reoperations in adulthood compared with women.

Tricuspid Valve Surgery in Adults With a Dysfunctional Systemic Right Ventricle Repair or Replace

Background— In patients with a right ventricle (RV) in the systemic position, tricuspid valve surgery for regurgitation beyond adolescence is a subject of debate. The aim of the present study was to evaluate the complications, survival, and benefit of tricuspid surgery in adult patients with an atrium-level correction for transposition of the great arteries or congenitally corrected transposition of the great arteries. Methods and Results— All adult patients (n=16; 7 men, 9 women; age 35±11 years) who underwent tricuspid valvuloplasty (n=8) or replacement (n=8) in the period 1999 to 2008 were included. Complications and survival were analyzed, and postoperative changes in RV function and functional class were evaluated. Tricuspid regurgitation was graded 1 to 4 according to its severity, RV dysfunction was graded as 1 to 4 (1=no dysfunction to 4=severe dysfunction), and functional status was determined according to New York Heart Association class. Although complications occurred in 11 patients, all could be managed adequately. Three patients died 109, 180, and 659 days after surgery, respectively, the first patient after tricuspid valve replacement and the latter 2 after tricuspid valvuloplasty. Overall, tricuspid valve function improved (from grade 3.1±0.8 to 0.9±1.0; P=0.001) and functional class improved (from 2.7±0.6 to 2.1±0.8; P=0.007), whereas RV function remained unchanged. After tricuspid valvuloplasty, however, recurrent moderate tricuspid valve regurgitation was observed frequently (n=3; 37%). Conclusions— Mortality is rather low after tricuspid surgery in adult patients with mild to moderate RV dysfunction. In general, tricuspid valve function and functional class improve significantly after surgery, and systemic RV function is preserved. Tricuspid valvuloplasty, however, is associated with a high rate of recurrence of regurgitation.

Brom's three-patch technique for repair of supravalvular aortic stenosis

OBJECTIVE Case histories of all patients (n = 29) operated on for supravalvular aortic stenosis from 1962 to the present were reviewed to study different techniques and outcomes. The technique of symmetric aortoplasty with 3 patches (1 in each sinus) is described and compared with other methods. METHODS Case reports were reviewed and follow-up was completed by contacting the patients (pediatric) cardiologist. We aimed for a last follow-up visit, including Doppler echocardiographic studies, in a period no more than 12 months earlier than December 1997. Supravalvular aortic stenosis was discrete in 25 and diffuse with involvement of the aortic arch and arch vessels in 4 patients. Additional anomalies were bicuspid aortic valve (n = 5), coarctation (n = 3), ascending aortic aneurysm (n = 1), mitral valve insufficiency (n = 2), pulmonary valvular stenosis (n = 1), and peripheral pulmonary artery stenosis (n = 2). Eleven patients had Williams syndrome and 1 patient had Noonan syndrome. Symmetric aortoplasty with 3 patches (1 in each sinus) was used in 13 patients, whereas other nonsymmetric methods (1, 2, or Y-shaped patches) were used in 16 patients. Mean follow-up was 10.5 years (range: 4 months-36 years). RESULTS All techniques adequately decreased the pressure gradient. Progression of preoperative aortic valve insufficiency or de novo regurgitation was not observed except in 1 patient in whom the patches inserted were too large. CONCLUSIONS No difference could be demonstrated in outcome for any surgical technique; however, reconstruction of the aortic root with autologous pericardial patches in each sinus after transection of the aorta has the advantage of symmetry while restoring the normal aortic root anatomy.