Gunther Fischer

Experience with transcatheter closure of secundum atrial septal defects using the Amplatzer septal occluder: a single centre study in 236 consecutive patients

Aim: To evaluate the safety and efficacy of transcatheter closure of secundum atrial septal defects (ASD) with the Amplatzer septal occluder. Methods: 236 consecutive patients with a significant ASD (age 6 months to 46 years, median 5 years; body weight 6.5–79 kg, median 18 kg) were considered for transcatheter closure with the Amplatzer septal occluder; 18 patients with defects that were too large or with a deficient inferior margin were excluded from attempted transcatheter closure after initial transthoracic (4) or transoesophageal echocardiography (14). Results: At cardiac catheterisation, devices were not implanted in 18 patients because the stretched diameter of the ASD was too large (4), the device was unstable (4), compromised the mitral valve (1), or obstructed the upper right pulmonary vein (1); eight patients with additional systemic or pulmonary vein anomalies (5) or a Qp:Qs less than 1.5 (3) were excluded after angiographic and haemodynamic assessment. Thus ASD closure was done successfully in 200 patients (procedure time 25–210 minutes, median 66 minutes; fluoroscopy time 2.5–60 minutes, median 12 minutes), among whom 22 had multiple ASDs (14) or a septal aneurysm (8). The diameter of the devices ranged between 6–34 mm. Severe procedure related complications (retroperitoneal bleeding, air embolism) occurred in two cases. At follow up (33 days to 4.3 years, median 2.3 years) complete closure was documented in 94%, with a trivial residual shunt in 12 patients. Conclusions: The Amplatzer septal occluder is very efficient and offered interventional ASD closure in 84.7% of our group of consecutive patients, with excellent intermediate results.

Initial human experience with the Amplatzer perimembranous ventricular septal occluder device

Transcatheter closure of perimembranous ventricular septal defects with coils or devices designed to close other lesions may be complicated by embolization or aortic insufficiency. A new asymmetric Amplatzer perimembranous ventricular septal occluder and delivery system was specifically designed for perimembranous defects. This report describes the first use of this device in 27 patients. Implantation was successful in 25 (93%), with 1 removed for device‐related aortic insufficiency and inability to position the delivery sheath in another. Device orientation was excellent when the device was initially advanced through a standard delivery sheath positioned in the left ventricular apex. Twenty‐three had complete occlusion within 1 week (92%), with a tiny (< 2 mm) residual shunt in the other two. In the 25 subjects with the device left in place, device‐related aortic or tricuspid insufficiency, arrhythmias, and embolization were not observed. These excellent acute results need to be confirmed by long‐term follow‐up. Cathet Cardiovasc Intervent 2003;58:238–245.

Outcome of the Norwood operation in patients with hypoplastic left heart syndrome: a 12-year single-center survey.

OBJECTIVE Recent advances in perioperative care have led to a decrease in mortality of children with hypoplastic left heart syndrome undergoing the Norwood operation. This study aimed to evaluate the outcome of the Norwood operation in a single center over 12 years and to identify clinical and anatomic risk factors for adverse early and longer term outcome. METHODS Full data on all 157 patients treated between 1996 and 2007 were analyzed. RESULTS Thirty-day mortality of the Norwood operation decreased from 21% in the first 3 years to 2.5% in the last 3 years. The estimated exponentially weighted moving average of early mortality after 157 Norwood operations was 2.3%. Risk factors were an aberrant right subclavian artery, the use and duration of circulatory arrest, and the duration of total support time. The anatomic subgroup mitral stenosis/aortic atresia and female gender tended to show an increased early mortality. In the group of patients who required postoperative cardiopulmonary resuscitation, the ascending aorta was significantly smaller than in the remainder (3.03 +/- 1.05 vs 3.63 +/- 1.41 mm). Interstage mortality was 15% until the initiation of a home surveillance program in 2005, which has zeroed it so far. It was significantly higher in the mitral stenosis/aortic atresia subgroup and tended to be higher in patients who required cardiopulmonary resuscitation after the Norwood operation. The best actuarial survival was observed in the mitral atresia/aortic atresia subgroup. CONCLUSION The Norwood operation can now be performed with low mortality. Patients with mitral stenosis/aortic atresia still constitute the most challenging subgroup.

Transcatheter closure of persistent ductus arteriosus in infants using the Amplatzer duct occluder

AIM To evaluate whether transcatheter closure with the Amplatzer duct occluder offers an alternative to surgical treatment in infants with a persistent ductus arteriosus. METHODS 12 patients under 1 year of age (age 1–11 months, body weight 2.6–8.7 kg) with clinical and echocardiographic findings of a significant duct were considered for transcatheter closure with the Amplatzer occluder. The device is made of a Nitinol and polyester fabric mesh and provides occlusion by stenting the duct. Measured angiographically, the narrowest diameter of the ducts ranged from 1.5–5 mm; in six patients pulmonary hypertension was also present. RESULTS The devices were implanted and complete duct occlusion was demonstrated during follow up in 10 patients. Procedure related difficulties occurred in nine of the 12 cases and led to relatively long procedure and fluoroscopy times (procedure time 50–180 minutes, median 80 minutes; fluoroscopy time 4.9–49 minutes, median 16 minutes). In two infants transcatheter closure could not be achieved and surgical duct ligation had to be carried out. CONCLUSIONS In small infants with a persistent ductus arteriosus the Amplatzer duct occluder offers an alternative to surgical treatment, but further improvement of the implantation system is necessary before the procedure can be recommended as the treatment of choice.

Influence of the pulmonary annulus diameter on pulmonary regurgitation and right ventricular pressure load after repair of tetralogy of Fallot

Objective: To assess the influence of the pulmonary annulus diameter after reconstruction of the right ventricular (RV) outflow tract at repair of tetralogy of Fallot on pulmonary regurgitation and RV pressure load; and to evaluate the impact of pulmonary regurgitation on RV size and function. Setting: Paediatric cardiology and diagnostic radiology departments of a tertiary referral centre. Patients: 67 patients were examined at a median of 4.8 years after repair of tetralogy of Fallot by means of biplane angiocardiography and magnetic resonance imaging (MRI). Main outcome measures: Pulmonary annulus diameter and area, pulmonary regurgitant fraction, RV to left ventricular (LV) systolic pressure ratio, RV end diastolic volume, and RV ejection fraction were assessed. Results: There was a significant positive correlation between pulmonary annulus area indexed to body surface area and pulmonary regurgitation (angiocardiography: r = 0.55, p < 0.001; MRI: r = 0.59, p < 0.001). No significant correlation was found between pulmonary annulus index and RV to LV systolic pressure ratio even in patients with small pulmonary annulus areas (r = −0.24, NS). Pulmonary regurgitant fraction was positively correlated with normalised RV end diastolic volume (angiocardiography: r = 0.42, p < 0.05; MRI: r = 0.56, p < 0.01). RV ejection fraction decreased with increasing pulmonary regurgitation (angiocardiography: r = −0.42, p < 0.05; MRI: r = −0.41, p < 0.05). Conclusions: The extent of pulmonary regurgitation after tetralogy of Fallot repair correlates with the postoperative size of the pulmonary annulus and is closely correlated with the enlargement of the RV. An enlargement of the pulmonary annulus to the second lower standard deviation of normal results in a decrease of pulmonary regurgitation and is sufficient to achieve adequate RV pressure unloading.

Device closure of ventricular septal defects by hybrid procedures: A multicenter retrospective study†

Objective: This study reports on the feasibility, efficacy, and outcome of hybrid procedures to close ventricular septal defects (VSD), reflecting the experience of 11 centers in Germany, Austria, and Switzerland. Background: Beating heart closure of VSD has attracted interest in small infants, complex anomalies and postinfarction scenarios where patients are at high risk during surgery. Perventricular or intraoperative device placement allows access to the lesions where percutaneous delivery is limited. Methods: Between December 2001 and April 2009, placement of Amplatzer septal occluders was attempted in 26 patients. The defects were located in the perimembranous (n = 5) and muscular septum (n = 21). In 20 patients, a perventricular approach was used, and, in six, the occluders were placed under direct visualization being part of a complex heart surgery. Results: In 23 of 26 procedures, device placement was successful (88.5%). The mean defect size was 7.8 mm (range, 3.5–20). The occluder types were perimembranous VSD occluder (n = 4), muscular VSD occluder (n = 20), postinfarct VSD occluder (n = 1), and ASD occluder (n = 1) with a ratio device/defect of 0.9–2.4 (median 1.15). Device removal was necessary in three due to arrhythmia, malpositioning, and additional defects. Pericardial effusion occurred once. In the remaining 22 patients, there were no procedure or device‐related complications. During mean follow up of 1.4 years (range, 1 day–3.9 years), a residual shunt that was more than trivial was observed in one patient out of 21 successful procedures. Conclusions: Perventricular and intraoperative device closure of VSD is as effective as a surgical patch and averts the increased morbidity of conventional surgical repair in a subgroup of high‐risk patients.

Transcatheter closure of coronary arterial fistulas using the new Amplatzer vascular plug.

We report our initial experience in using the Amplatzer vascular plug for closure of coronary arterial fistulas. The self-expanding, cylindrical, device is made from Nitinol wire mesh, and is available from 4 to 16 millimetres in diameter. We have now used the device to close fistulas in 3 patients, aged from 3 to 14 years, who presented with ratios of pulmonary-to-systemic flow from 1.5 to 3. In 2 patients, fistulas arising from the proximal right and left coronary arteries, with maximal diameters of 9 and 10 millimetres, respectively, had their narrowest diameter, of 6 millimetres, proximal to the entrance into the right atrium via a saccular aneurysm. The third fistula, with a maximal diameter of 16 millimetres, and with its origin from the circumflex coronary artery, entered the right atrium with nearly unrestricted flow, its narrowest diameter being 8 millimetres. For interventional closure, we chose plugs twice the diameter of the narrowest segment of the fistula, thus using 2 devices of 12 millimetres and one of 16 millimetres diameter. An arteriovenous loop was established through the fistula by snaring an exchange guide wire. Using a 7 or 8 French guide catheter inserted through the femoral vein, all plugs were placed at the narrowest segment of the fistula, leading to immediate complete closure of 2 fistulas. The third patient, with a fistula of the circumflex coronary artery, who received the largest plug initially had residual flow, but the fistula was found to be completely occluded at 12 months follow-up examination. We have demonstrated, therefore, safe and effective usage of the new vascular plug for transcatheter closure of moderate- to large-sized coronary arterial fistulas. The plug offers an alternative to cardiac surgery, or occlusion using coils.

Adverse results of a decellularized tissue-engineered pulmonary valve in humans assessed with magnetic resonance imaging.

OBJECTIVES Matrix P® and Matrix P plus® tissue-engineered pulmonary valves (TEPV) were offered as an improvement for pulmonary valve replacement (PVR) because of recellularization by host cells. The high frequency of graft failure gave reason to evaluate the underlying morphological substrate using magnetic resonance imaging (MRI) and histology. METHODS Between June 2006 and August 2008, 17 Matrix P® and 10 Matrix P plus® TEPVs were implanted in 26 patients with a median age of 12.4 (range: 0.8-38.7, interquartile range: 6.1-18.1) years. The grafts were studied by MRI, and underwent histological examination when explantation was required. RESULTS Surgical (n = 13) or transcatheter (n = 1) TEPV replacement because of graft failure was needed in 14 cases (52%) 19 (0.5-53) months after implantation. MRI detected significant TEPV stenosis with mild insufficiency (V(max) = 3.7 ± (standard deviation) 0.5 m/s, regurgitant fraction (RGF) = 10 ± 3%) and stenosis with moderate-to-severe insufficiency (V(max) = 3.5 ± 0.8 m/s, RGF = 38 ± 10%) in 6 patients, respectively, and severe insufficiency (RGF = 40%) in 1 patient. In patients with graft failure, MRI showed hyperenhancement and TEPV wall thickening. Histology revealed severe inflammation, increased fibrous tissue and foreign-body reaction against valve leaflets and fascial tissue, while TEPV endothelialization was not detected in any case. CONCLUSIONS The high frequency of Matrix P® and Matrix P plus® graft failure can be related to inflammation and fibrosis revealed by MRI and histology. Our results do not support the use of these valves for PVR and suggest careful follow-up examinations, including MRI for early detection of graft inflammation and fibrosis.

Two-Dimensional Global Longitudinal Strain Rate Is a Preload Independent Index of Systemic Right Ventricular Contractility in Hypoplastic Left Heart Syndrome Patients After Fontan Operation

Background—Assessment of systemic right ventricular (RV) function in patients with hypoplastic left heart syndrome is important during long-term follow-up after Fontan repair. Traditional echocardiographic parameters to evaluate systolic ventricular function are affected by loading conditions. The only generally accepted load-independent parameter of systolic function, end systolic elastance (Ees), requires invasive catheterization. Therefore, we sought to determine if parameters obtained by 2-dimensional speckle tracking (2DST) were affected by acute changes in preload and correlated with catheterization-derived indices of RV contractility in hypoplastic left heart syndrome patients after Fontan palliation. Methods and Results—Fifty-two patients with hypoplastic left heart syndrome (median age, 6.6; range 2.9–22.2 years) were prospectively enrolled to have echocardiography and conductance catheter studies performed simultaneously. We compared traditional echo, 2-dimensional speckle tracking and catheterization-derived parameters during different states of preload at baseline and during dobutamine infusion. Global longitudinal strain (S) showed a tendency to decrease with preload reduction, whereas global longitudinal strain rate (SR) did not change (S: −17.7±3.4% versus −16.9±3.8%, P=0.08; SR: −1.30±0.29 versus −1.34±0.34 s−1, P=0.3). S did not change with dobutamine infusion (−17.7±3.4% versus −18.4±3.9%, P=0.24), whereas SR increased significantly (−1.30±0.29 versus −2.26±0.49 s−1, P<0.001). RV Ees correlated with SR (rs= −0.47, P<0.001), but not with S (rs=0.07, P=0.5) or other echocardiographic parameters. Conclusions—In contrast to S, SR was not affected by preload and correlated with Ees of the systemic RV. SR may be a useful noninvasive surrogate of RV contractility and suitable for follow-up of patients with hypoplastic left heart syndrome after Fontan palliation.

Percutaneous pulmonary valve replacement: autologous tissue-engineered valved stents

AIMS Percutaneous implantation has already been used clinically and is a great option for treating young patients. The use of autologous tissue-engineered valved stents might solve the problem of degeneration and limited durability of biological heart valves. METHODS AND RESULTS Porcine pulmonary heart valves and small intestinal submucosa were obtained from a slaughterhouse. The intestinal submucosa was used to cover the inside of the porcine pulmonary valved stents. Endothelial cells (ECs) and autologous myofibroblasts (MFs) were used from carotid artery segments of juvenile sheep. After MF seeding, constructs were placed in a dynamic bioreactor system and cultured for 16 days. After additional EC seeding, tissue-engineered valved stents were percutaneously deployed into the annulus of the pulmonary valve (n = 9). Angiography was performed at implantation and 4-week follow-up. Constructs were analysed radiographically, by post-mortem examination, and microscopically. In all but one case, orthotopic positioning of the stents (n = 6) at the time of implantation and explantation was observed angiographically, macroscopically, and by computer tomography scan and demonstrated normal valve function (n = 7). Gross morphology confirmed excellent opening and closure characteristics of all leaflets after 4 weeks (n = 7). Strong expression of α-smooth muscle actin in neo-interstitial cells and of von Willebrand factor and PECAM-1 in ECs was revealed by immunocytochemistry. CONCLUSION Good functioning and morphological characteristics were observed after percutaneous tissue-engineered valved stent implantation with autologous cells. This implantation of autologous tissue-engineered valved stents will become a valid future option in adolescents.