Ingo Daehnert

Immediate primary transcatheter closure of postinfarction ventricular septal defects

AIMS Immediate surgical repair of ventricular septal defect (VSD) complicating acute myocardial infarction is associated with high mortality. Percutaneous device closure appears to be safe and effective in patients treated for a residual shunt after initial surgical closure, as well as in patients with a chronic post-infarct VSD. Primary transcatheter VSD closure in the acute setting may also offer advantages over surgery. METHODS AND RESULTS Between September 2003 and February 2008, 29 consecutive patients underwent primary transcatheter VSD closure. Clinical, procedural, and outcome data were collected. Patients were divided into those with and those without cardiogenic shock at presentation for risk stratification. The median follow-up time of surviving patients was 730 days. The median time between VSD occurrence and closure was 1 day [interquartile range (IQR) 1-3] and the initial procedural success rate was 86%. The shunt (Qp:Qs) could be reduced from 3.3 (IQR 2.3-3.8) to 1.4 (IQR 1.2-1.7; P < 0.001). Procedure-related complications such as major residual shunting, left ventricular rupture, and device embolization occurred in 41%. The overall 30-day survival rate was 35%. Mortality was higher for cardiogenic shock in comparison to non-shock patients (88 vs. 38%, P < 0.001). CONCLUSION Interventional acute VSD closure is a promising technique that can be performed with a high procedural success rate and may offer an alternative to surgery. Despite the less invasive technique, mortality of postinfarction VSD remains high, particularly in patients with cardiogenic shock. Further developments in devices and delivery techniques are required.

Transcatheter Closure of Atrial Septal Defects Without Fluoroscopy Feasibility of a New Method

BACKGROUND In an effort to reduce x-ray exposure, we developed a technique for transcatheter closure of atrial septal defects under echocardiographic guidance without fluoroscopy. To assess the efficiency of this procedure for routine use, we compared our initial results with those for the conventional procedure. METHODS AND RESULTS Twenty-two randomly selected patients (median age 18 years; range 2 to 66 years) with atrial septal defects (n=13) or patent foramen ovale (n=9) underwent cardiac catheterization for possible interventional defect closure with echocardiography as the only imaging tool. Median stretched diameter was 9 mm (range 6 to 26 mm); median left-to-right shunt over the atrial septal defects was Qp/Qs=1.8 (range 1.5 to 2.6). An Amplatzer septal occluder was successfully implanted in 19 defects without fluoroscopy and in 3 with the help of radiography. After 1 month, complete defect closure was documented in all patients. Compared with the conventional procedure of a control group of 131 patients, procedure times were not significantly different (88 versus 100 minutes; P=0.09). However, the study group received significantly higher doses of propofol for sedation (9.9 versus 5.6 mg/kg body weight; P=0.002) owing to extended transesophageal echocardiography. CONCLUSIONS In the majority of patients in whom transcatheter closure of interatrial communications with the Amplatzer septal occluder is possible, the procedure can be safely performed under echocardiographic guidance without fluoroscopy.

Interventions in leaks and obstructions of the interatrial baffle late after Mustard and Senning correction for transposition of the great arteries

The objective of this study was to describe the institutional experience with interventional treatment of atrial sequelae late after atrial correction for transposition of the great arteries (TGA). A retrospective observational study identified 13 long‐term survivors of atrial correction for TGA (median age, 20.5 years; range, 13.8–33.0) with atrial inflow obstruction and/or interatrial defects. Balloon‐expandable stents were used for relief of atrial inflow obstructions and interatrial defects closed with devices. Feasibility, periprocedural complications, residual or new obstructions or leaks at follow‐up were investigated. Fourteen successful procedures were performed in 12 patients; one procedure failed. Five stents were placed for obstruction of the superior caval vein, three for obstruction of the inferior caval vein, and one for obstruction of the pulmonary venous return. Five septal occluders were implanted. Localization of the interatrial defects required atypical implantation techniques and resulted in atypical device positions. No complications occurred with stent or device implantation. There were no residual shunts through or around the septal occluders. None of the patients had new implant‐related obstruction or leakage during a median follow‐up of 21 months (range, 6–45). Stent implantation for obstruction of the pulmonary or systemic venous return in patients after atrial redirection for TGA is safe and effective. Follow‐up suggests excellent maintenance of patency. Interatrial defects can be closed with septal occluders despite atypical defect positions in these patients. Combined use of both devices in adjacent positions is feasible. These interventions help to avoid high‐risk surgery.

Transcatheter closure of atrial septal defects under echocardiographic guidance without X-ray: initial experiences.

BACKGROUND Transcatheter closure of atrial septal defects is performed under fluoroscopy, but echocardiography has gained an important role in the procedure. With the new Amplatzer Septal Occluder a device has become available which is easy to implant with minimal fluoroscopy time. We developed an interventional procedure with this device under transesophageal echocardiography alone without fluoroscopy. METHODS AND RESULTS Four patients (3 to 16 years of age, bodyweight 14 to 60 kg) with atrial septal defects centrally located in the oval fossa were elected for transcatheter closure. After sedation with midazolam and propofol a diagnostic and interventional catheterization was performed in all cases without fluoroscopy. Oxymetric shunt was Qp: Qs = 1.7 (1.5 to 2.1). Under transesophageal echocardiography, the defects were sized over the wire with a balloon catheter. Mean balloon stretched diameter was 10 mm (7 to 14 mm). Under transesophageal echocardiography an Amplatzer Septal Occluder was placed into the defect. In two patients this was achieved with a 5 MHz monoplane pediatric transducer, in two patients a 10mm 5 MHz multiplane probe was used. Complete closure was achieved in all patients and no complications were encountered. CONCLUSION We conclude that in selected cases with an atrial septal defect located in the oval fossa and clear-cut echocardiographic findings, an Amplatzer Septal Occluder can be safely deployed under echocardiographic guidance alone.

Moderate versus deep hypothermia for the arterial switch operation — experience with 100 consecutive patients

OBJECTIVES To evaluate the impact of moderate versus deep perioperative hypothermia on postoperative morbidity in patients receiving the arterial switch operation (ASO). METHODS One hundred consecutive patients received the ASO from 9/98 to 4/06 using temperature-corrected full-flow moderate (M>24 degrees C, n=51) or deep hypothermic cardiopulmonary bypass (CPB) (D <20 degrees C, n=49). Complex TGA morphology was present in 33 patients (M: 27.4%, D: 38.8%, n.s.). Median age was 9 days (M) versus 10 days (D) and body weight was 3.5+/-0.7 kg (M) versus 3.6+/-0.9 kg (D) (both p=n.s.). Follow-up was 3.7+/-2.1 years. RESULTS Lowest perioperative rectal temperature was 25.3+/-1.1 degrees C (M) versus 19.0+/-0.8 degrees C (D), p<0.001. Intraoperative blood transfusion (M: 231+/-47 ml, D: 252+/-112 ml, p=0.04) and postoperative lactate level (M: 3.2+/-1.3 mmol/l, D: 3.8+/-2.4 mmol/l, p=0.02) were lower under moderate hypothermia. One patient (D) suffered myocardial ischemia, required ECMO support and died. All other patients were safely weaned from CPB using dopamine (M: 3.0 microg/kg min, D: 3.4 microg/kg min, n.s.) and dobutamine (M: 5.6 microg/kg min, D: 6.7 microg/kg min, p=0.048). Secondary chest closure was performed in 41% (M) versus 59% (D) (p=0.04). Patients were extubated after 89 h (M) versus 126 h (D) (p=0.03). Under moderate hypothermia ICU stay (M: 8.4+/-4.7 days, D: 12.0+/-13.8 days, p=0.03) and hospital stay (M: 12.8+/-6.8 days, D: 20.7+/-15.5 days, p=0.001) were shorter. Five-year freedom from reoperation was 97.0% for simple and 85.2% for complex TGA with RVOT reconstruction in 4/6 patients. CONCLUSIONS The ASO under full-flow moderate compared to deep hypothermia was advantageous regarding length of procedure and primary chest closure rate. Moderate hypothermia seemed to be beneficial for pulmonary recovery, length of chest tube drainage treatment and inotropic support. No worse early or long-term effects of moderate hypothermia were found.

Role of connexins in human congenital heart disease: the chicken and egg problem

Inborn cardiac diseases are among the most frequent congenital anomalies and are the main cause of death in infants within the first year of age in industrialized countries when not adequately treated. They can be divided into simple and complex cardiac malformations. The former ones, for instance atrial and ventricular septal defects, valvular or subvalvular stenosis or insufficiency account for up to 80% of cardiac abnormalities. The latter ones, for example transposition of the great vessels, Tetralogy of Fallot or Shone’s anomaly often do not involve only the heart, but also the great vessels and although occurring less frequently, these severe cardiac malformations will become symptomatic within the first months of age and have a high risk of mortality if the patients remain untreated. In the last decade, there is increasing evidence that cardiac gap junction proteins, the connexins (Cx), might have an impact on cardiac anomalies. In the heart, mainly three of them (Cx40, Cx43, and Cx45) are differentially expressed with regard to temporal organogenesis and to their spatial distribution in the heart. These proteins, forming gap junction channels, are most important for a normal electrical conduction and coordinated synchronous heart muscle contraction and also for the normal embryonic development of the heart. Animal and also some human studies revealed that at least in some cardiac malformations alterations in certain gap junction proteins are present but until today no particular gap junction mutation could be assigned to a specific cardiac anomaly. As gap junctions have often been supposed to transmit growth and differentiation signals from cell to cell it is reasonable to assume that they are somehow involved in misdirected growth present in many inborn heart diseases playing a primary or contributory role. This review addresses the potentional role of gap junctions in the development of inborn heart anomalies like the conotruncal heart defects.

Opposing and synergistic effects of cyclic mechanical stretch and α- or β-adrenergic stimulation on the cardiac gap junction protein Cx43

In the heart the most prominent cardiac gap junction protein is connexin43 (Cx43). Increased Cx43 expression has been identified in cardiac hypertrophy and may contribute to arrhythmias. Besides acute effects on gap junction channel function, chronic regulation of Cx43 expression can affect intercellular communication. Since both cyclic mechanical stretch (CMS) and catecholamines play an important role in cardiac physiology and pathophysiology, we wanted to elucidate whether a prolonged β- or α-adrenoceptor stimulation may modulate the effects of CMS on Cx43 expression. Neonatal rat cardiomyocytes were cultured on flexible 6-well plates. Thereafter, cells were kept static without any treatment or stimulated with 0.1μmol/L isoprenaline or phenylephrine for 24h without or with additional CMS (1Hz; 10% elongation). Isoprenaline and phenylephrine given alone significantly increased Cx43-protein and -mRNA level. Also CMS resulted in a significant Cx43-protein and -mRNA up-regulation. The combined treatment of the cells with either isoprenaline or phenylephrine and stretch also resulted in an up-regulation of Cx43-protein and -mRNA, which did not exceed those of stretch, isoprenaline or phenylephrine alone. However, while CMS reduced the Cx43-protein/mRNA ratio, adrenergic stimulation increased Cx43-protein/mRNA ratio. While isoprenaline and phenylephrine increased Cx43-phosphorylation, additional CMS significantly reduced P-Cx43/Cx43 ratio. For further investigation of the underlying signal transduction pathway, we examined the phosphorylated forms of ERK1/2, GSK3β and AKT and could demonstrate that these protein kinases are also significantly up-regulated following stretch or adrenoceptor stimulation. Again the combined treatment of cardiomyocytes with CMS and isoprenaline or phenylephrine had no additive effects. Thus, the combination of α- or β-adrenoceptor stimulation and CMS up-regulates Cx43 expression and leads to phosphorylation of ERK1/2 and AKT (=activation) and of GSK3β (=inactivation). There were no significant additive effects compared to CMS or adrenergic stimulation alone indicating a possible ceiling effect. However, CMS and adrenergic stimulation differentially affected Cx43-protein/mRNA ratio and Cx43-phosphorylation.

Interventional closure of atrial septal defects with the Solysafe Septal Occluder--preliminary results in children.

BACKGROUND To report usability, safety, and efficacy of the self-centering Solysafe Septal Occluder for transcatheter closure of secundum type atrial septal defect (ASD) in paediatric patients. METHODS Retrospective observational clinical study in two tertiary care centers for congenital heart diseases. PATIENTS First 37 (median age 8.7 years, 68% female) consecutive patients with an ASD stretched diameter up to 22 mm in whom a Solysafe Septal Occluder was used to close a haemodynamically significant ASD. INTERVENTIONS Transcatheter closure of ASD was performed under general anaesthesia with trans-esophageal echo guidance. Stretched diameter of the ASD was assessed by balloon sizing. MAIN OUTCOME MEASURES Rate of success, complete closure rate, and complications (defined as vascular complications, device-related complications such as embolism, thrombus formation, device erosions, infections, and arrhythmia) during follow up. RESULTS 37 procedures were performed, success rate was 87% (32 of 37 pts.). A missing retroaortic rim was the main reason for device failure. Complete ASD closure rate was 78% immediately in cath lab (25 of 32 pts.), 90% after four weeks (28 of 31 pts.), 94% after three months (29 of 31 pts.), and 100% after six months (20 of 20 pts.). Procedure-related complication was femoral vein thrombosis in one patient. CONCLUSIONS The Solysafe Septal Occluder is a feasible, safe, and clinically efficient new device for interventional closure of small to medium sized ASDs less than 23 mm stretched diameter in childhood. Limitations for the Solysafe device are ASDs with absent retroaortic rims and very small children with a body weight<10 kg.

Effectiveness of simulator-based echocardiography training of noncardiologists in congenital heart diseases.

Congenital heart diseases (CHD) are responsible for substantial morbidity and mortality in neonates. The preliminary diagnosis often is made by noncardiologists. For this reason, there is a huge demand of training in echocardiography of CHD. This is difficult to achieve due to limited resources of specialized centers.

Giant Cell Myocarditis Mimicking Idiopathic Fascicular Ventricular Tachycardia

We report an adolescent with giant cell myocarditis (GCM) mimicking tachycardia-induced cardiomyopathy. His electrocardiogram (ECG) was typical for an incessant form of fascicular ventricular tachycardia. The patient rapidly deteriorated and required support using extracorporeal membrane oxygenation (ECMO). Biopsy revealed GCM with massive myocyte necrosis. He was successfully heart transplanted 6 days after admission.