Intervention in the critically ill neonate and infant with hypoplastic left heart syndrome and intact atrial septum

Neonates that present with hypoplastic left heart syndrome (HLHS) and intact atrial septum (IAS) pose a major management problem for the pediatric cardiac team. They are critically ill newborns with profound hypoxemia and acidosis that require immediate attention. Controversy exists as to the most appropriate management strategy. In one series where a primary and emergent surgical-staged reconstructive procedure was performed, the in-house hospital mortality was 65% and the overall survival was 17%. With equal abysmal results, transcatheter creation of an atrial septal defect (ASD) using conventional balloon atrial septostomy (BAS) with or without the combination of blade atrial septotomy had an unacceptable high risk of cardiac perforation leading to tamponade and death. However, using more modern transcatheter techniques of transseptal perforation of the atrial septum followed by progressive and serial balloon septoplasty, creating an ASD, significantly reduced the risk of the procedure. In one series, 16 consecutive neonates underwent this type of interventional procedure without procedural mortality. The management strategy of creating an ASD in the catheterization lab followed by Stage I reconstructive surgical repair 3-5 days after the initial catheterization procedure improved the in-house survival to 57%. Unfortunately, there continues to be significant attrition of these patients undergoing Stage II and III reconstructive repair, which supports cardiac transplantation as an alternative strategy. There have been echocardiographic and histopathologic studies of these neonates, and an important echo classification of left atrial morphology has been described with perhaps some prognostic implication. In addition, autopsy specimens have demonstrated significant "arterialization" of the pulmonary venous architecture that likely dooms the patient with single ventricle physiology to a poor outcome. Future improvement in transcatheter techniques and materials offer promise in palliating these critically ill neonates. The concept of radiofrequency energy perforating catheters has great merit and may reduce the risk of cardiac perforation as compared with the rigid and long transseptal needle. Echocardiographic imaging at the time of entry through the IAS may improve the safety as well. The novel concepts of "butterfly" or "dog-bone" stents placed across the atrial septum creates a precisely sized ASD that may be more conducive to effectively lower left atrial hypertension, yet avoids excessive pulmonary blood flow associated with large atrial communications. In addition, new materials, such as the Cutting Balloon Catheter, may offer promise in creating ASDs in these patients. A more aggressive approach would be to consider intrauterine fetal transcatheter opening of the IAS using modified techniques that have been attempted for left ventricular outflow tract obstruction. Unfortunately to date, the results of attempted relief of aortic valve stenosis have been extremely poor. Finally, we as interventionalists need to continue to improve our skills to help in the complex management of these critically ill neonates and infants. Only through continued efforts of the entire cardiac team of intensivists, cardiologists, cardiothoracic surgeons, and interventionalists will our management strategy be defined to maximize the future outcome in this group of patients.     

Pulmonary atresia with intact ventricular septum

Opinion statement The prognosis for patients with pulmonary atresia with intact ventricular septum is poor with and without conventional surgical treatment. Because of this reason, a comprehensive program of medical, transcatheter, and surgical treatment is necessary to improve the long-term outlook of these infants. Algorithms of management plans should be developed based on the presence of right ventricular-dependent coronary circulation as well as size and morphology of the right ventricle. In a tripartite or bipartite right ventricle, transcatheter radiofrequency perforation is preferable. Alternatively, surgical valvotomy may be performed. Augmentation of pulmonary blood flow by prolonged infusion of prostaglandin E₁, stenting the ductus, or a surgical modified Blalock-Taussig shunt may be necessary in some of these patients. In patients with a unipartite or very small right ventricle or a right ventricular-dependent coronary circulation (Tricuspid valve Z score < -2.5), augmentation of pulmonary flow along with atrial septostomy should be undertaken. Follow-up studies to determine the feasibility of biventricular repair should be undertaken and, if feasible, surgical or transcatheter methods may be used to achieve the goals. If not suitable for biventricular repair, one-ventricle (Fontan) or one and one-half ventricular repair should be considered. Comprehensive and well-planned treatment algorithms may help improve survival rate.     

Radiofrequency coagulation of ventricular myocardium: Improved prediction of lesion size by monitoring catheter tip temperature

To assess the importance of voltage, current, impedance andcatheter tip temperature for the prediction of the size of tissueinjury induced by transcatheter radiofrequency application,radiofrequency pulses (500 kHz) were delivered both in vitroand in vivo to isolated ventricular preparations and the intactcanine heart, respectively. Radiofrequency coagulations wereperformed using unipolar electrode configuration. Besides measurementsof current and voltage which were used to calculate the deliveredpower and tissue impedance, the catheter tip temperature wasmonitored during each application using specially designed 6FUSCI catheters with a built-in nickel/chromium-nickel thermoelement.Lesion dimensions were measured and the correlation betweenlesion volume and delivered radiofrequency energy, maximum changesin catheter tip temperature and the integral of the temperaturecurve were calculated. First, in a pilot in vitro investigation,50 radiofrequency coagulations (3.2 W–22.4 W, pulse duration10 s) were performed in ventricular preparations fromfreshlyexcised dog hearts. The correlation between applied radiofrequencyenergy and lesion volume was 0.87; the correlation between maximalcatheter tip temperature and lesion volume was 0.82; the correlationbetween temperature integral and lesion volume was 0.9. In theintact dog heart, 44 radiofrequency pulses were delivered tothe left and right ventricular endocardium in 12 anaesthetizeddogs (exposure time: 10 s). Delivered power ranged between 5.6Wand 24.6 W; tissue impedance varied between 92 and 364 ; lesionvolume measured 0–273 mm³; developed peak temperaturesranged from 16.25°C to 196°C. The calculated integralbeneath temperature curves measured 126–1971°C.s.The correlation between applied radio-frequency energy and lesionvolume was 0.32; the correlation between maximal catheter tiptemperature and lesion volume was 0.61. Temperature integralcorrelated best with the assessed volume of my ocardial necrosis(r = 0.7). No significant arrhythmogenic or haemodynamic side-effectswere observed. Macroscopic examination showed a central depressionsurrounded by a zone of homogenous coagulation. Vaporizationand crater formation up to a depth of 4 mm were observed followingthree radiofrequency discharges. In two of these cases, rapidchanges and oscillation of catheter tip temperature were observed.Thus, monitoring of catheter tip temperature during radiofrequencyenergy application improves the prediction of lesion size. Inaddition, temperature monitoring might improve the safety ofthe procedure with respect to the risk of perforation.     

Guidewire-induced coronary artery perforation treated with transcatheter injection of polyvinyl alcohol form.

We describe a first case of successful transcatheter management of guidewire-induced distal coronary artery perforation and impending cardiac tamponade, which developed during percutaneous coronary angioplasty, with transcatheter injection of polyvinyl alcohol form. This method may be an effective alternative in the management of distal coronary artery perforation requiring surgical repair.     

The Transcatheter Management of the Neonate and Infant with Pulmonary Atresia and Intact Ventricular Septum

The optimal management of the neonate and infant with pulmonary atresia (PA) and intact ventricular septum (IVS) remains controversial. The ultimate aim of any treatment algorithm is to achieve a four-chambered, biventricular, completely separated circulation. In 1991, transcatheter perforation of the atretic membrane followed by successful balloon valvuloplasty was reported using a laser-assisted guidewire in the United Kingdom and the stiff end of a guidewire in the United States. The following year, a radiofrequency (RF) guidewire was successfully used, while stenting of the ductus arteriosus to maintain adequate pulmonary blood was also reported. Most recently, a steerable 5 Fr RF catheter was used to "burn" the atretic membrane. From a series of 15 publications, a total of 69 neonates underwent attempted pulmonary valve perforation: 17 laser guidewire, 28 RF guidewire, 25 stiff end guidewire, and 1 steerable RF catheter. Successful perforation by technique was: 82.4% laser, 88.5% RF, 68% stiff end, and 100% steerable RF. The accumulative success rate was 79.7%, mortality 4.3%, major complication 18%, and need for additional pulmonary blood 48%. Follow-up thus far has been encouraging. The technique of transcatheter perforation of the atretic pulmonary valve membrane is demanding and not without risk, but in experienced hands can be successful nearly 90% of the time using the RF guidewire. RF energy is commonly used for other cardiac problems and has inherent cost and availability advantages over laser energy. Since nearly 50% of the neonates still require additional pulmonary blood flow, the interventionalist must be capable and ready to stent the PDA, or send to surgery. The neonate with right ventricular (RV) dominant coronary circulation remains a high risk group. However, careful cardiac catheterization with temporary transcatheter RV decompression may lead to a better understanding of this complex physiology.     

特发性心房颤动射频消融术后左心功能心脏超声评价及预后的研究

目的研究导管射频消融术对特发性心房颤动(AF)患者左心功能及预后的影响。方法入选2007年10月至2009年11月在贵州省人民医院心内科成功行射频消融术后未复发的特发性AF患者28例。包括持续性AF组(SAF)13例,阵发性AF组(PAF)15例。于术前、术后1个月、半年、1年时随访超声心动图检查,分别测量二尖瓣血流频谱、左心房射血力(LAEF)及左心室射血分数(LVEF),同时行生存质量问卷调查。结果射频消融术成功治疗AF后,3例SAF组患者二尖瓣血流频谱A峰未出现,其余A峰流速较术前明显增加(P<0.05);术后半年PAF组患者LAEF基本恢复正常(P<0.05),术后1年SAF组患者LAEF有所升高,但和术前相比差异无统计学意义(P>0.05);术后各组左心室射血分数较术前增加[SAF组(55.79±8.96)%对(48.13±5.18)%,P<0.05;PAF组(64.59±7.41)%对(51.09±5.63)%,P<0.01];各组总生存质量评分显著改善(P<0.05);PAF患者左心功能较SAF组恢复更为明显(P<0.05)。结论射频消融术后PAF患者左心功能恢复较SAF更加显著及迅速,预后更好,提示SAF患者射频消融术后须长期随访及相应治疗。     

Carbon dioxide-enhanced sonographically guided radiofrequency ablation combined with transcatheter arterial chemoembolization for sonographically undetectable hepatocellular carcinoma

A 73-year-old man was diagnosed as having hepatitis C virus-related liver cirrhosis 11 years ago. Two years ago, he developed hepatocellular carcinoma in segment 6 of the right lobe and received radiofrequency ablation. This time, he was admitted to our hospital with a local recurrence in segment 6 of the liver. Standard sonography could not visualize the lesion clearly. However, carbon dioxide-enhanced sonogram clearly showed the whole lesion, so a needle electrode could be inserted precisely, allowing safe and accurate radiofrequency ablation. By combining radiofrequency ablation with transcatheter arterial chemoembolization, complete tumor necrosis was achieved without the need to perform additional ablation. In conclusion, carbon dioxide-enhanced sonographically guided radiofrequency ablation combined with transcatheter arterial chemoembolization is useful for complete cure of localized tumors, such as recurrent hepatocellular carcinoma, which cannot be detected clearly by conventional sonography.     

Radiofrequency-assisted "reconstruction" of the right ventricular outflow tract in muscular pulmonary atresia with ventricular septal defect.

A case of pulmonary atresia with ventricular septal defect is reported in which a communication was established between the right ventricle and the hypoplastic pulmonary artery by intervention, despite muscular atresia of the right ventricular outflow tract. The atresia was perforated with a special designed radiofrequency catheter (Osypka). After the creation of a canal within the muscular atresia, balloon dilatation (diameters 2, 3.5, and 7.2 mm) was performed. Arterial oxygen saturation increased from 64% to 78%. Lateral deviation of the radiofrequency catheter resulting in a lateral perforation of the atretic muscular infundibulum was well tolerated without later sequelae. Early restenosis within two weeks necessitated the implantation of a stent within the "recanalised" atresia resulting in an increased anterograde flow to the pulmonary artery. This case shows that "recanalisation" of muscular atresia of the pulmonary artery by radiofrequency is a promising technique. Additionally, stent implantation into the infundibulum to prevent restenosis is a first step to interventional right ventricular outflow tract reconstruction.     

Transcatheter radiofrequency ablation in the canine right atrium

The feasibility of using radiofrequency energy for potential ablation of atrial tachycardia foci was assessed by performing transcatheter ablation in the right atrium in 11 closed-chest dogs. Single-pulsed radiofrequency (750 kHz) energy was delivered to the right atrium (29-254 J) between the tip electrode of a standard 6 Fr quadripolar catheter and a chest patch electrode. There were no significant arrhythmias or complications noted. Dogs were sacrificed 0-29 days after ablation to assess acute and subacute effects of this technique. Of 47 attempted ablations, 36 well-delineated coagulative lesions were identified. The lesions had a mean dimension of 5.2 +/- 0.57 mm (+/- SE) in length, 3.9 +/- 0.27 mm in width, and 2.6 +/- 0.17 mm in depth. Transmural necrosis was noted in 6 of 36 lesions (17%) without perforation. A thin layer of mural thrombus was found in 5 of 36 lesions (14%). Thus, this technique appears to be feasible and relatively safe for right atrial ablations in a short-term follow-up period. The potential application of this method to ablate right atrial tachycardia foci needs to be further investigated.     

Perforation of the aorta after percutaneous closure of an atrial septal defect with an Amplatz prosthesis,presenting with acute severe hemolysis

We report a case of aortic perforation three weeks after transcatheter occlusion of an atrial septal defect (ASD) by an Amplatzer device. Revealed by acute hemolysis, this complication needed an emergency surgical operation. The fistula between the no coronary Valsalva sinus of the aorta and the left atrium was repaired. The ASD was closed by patch. This serious accident should consider a short antero-superior rim as a risk factor for aortic perforation in transcatheter closure for ASD.     

Thermal compression and molding of atherosclerotic vascular tissue with use of radiofrequency energy: implications for radiofrequency balloon angioplasty

The combined delivery of pressure and thermal energy may effectively remodel intraluminal atherosclerotic plaque and fuse intimal tears. To test these hypotheses with use of a non-laser thermal energy source, radiofrequency energy was delivered to postmortem human atherosclerotic vessels from a metal "hot-tip" catheter, block-mounted bipolar electrodes and from a prototype radiofrequency balloon catheter. Sixty-two radiofrequency doses delivered from a metal electrode tip produced dose-dependent ablation of atherosclerotic plaque, ranging from clean and shallow craters with histologic evidence of thermal compression at doses less than 40 J to tissue charring and vaporization at higher (greater than 80 J) doses. Lesion dimensions ranged between 3.14 and 3.79 mm in diameter and 0.20 and 0.47 mm in depth. Tissue perforation was not observed. To test the potential for radiofrequency fusion of intimal tears, 5 atm of pressure and 200 J radiofrequency energy were delivered from block-mounted bipolar electrodes to 48 segments of human atherosclerotic aorta, which had been manually separated into intima-media and media-adventitial layers. Significantly stronger tissue fusion resulted (28.5 +/- 3.3 g) with radiofrequency compared with that with pressure alone (4.8 +/- 0.26 g; p less than 0.0001). A prototype radiofrequency balloon catheter was used to deliver 3 atm of balloon pressure with or without 200 J radiofrequency energy to 20 postmortem human atherosclerotic arterial segments. In 10 of 10 radiofrequency-treated vessels, thermal "molding" of both normal and atherosclerotic vessel wall segments resulted with increased luminal diameter and histologic evidence of medial myocyte damage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Outcomes of transcatheter valvotomy in patients with pulmonary atresia and intact ventricular septum

The results of transcatheter valvotomy in pulmonary atresia with intact ventricular septum (PA-IVS) patients are presented with an attempt to identify the predictive factors for pulmonary valvotomy alone as definitive treatment. Between June 1995 and December 1997, 14 PA-IVS neonates with tripartite right ventricle underwent an attempted pulmonary valvotomy. For perforation of the pulmonary valve, a guidewire was used in 4, and a radiofrequency guidewire in 10 patients. Two outcome groups were identified. Group I included those in whom transcatheter treatment achieved a definitive success; group II patients required surgery despite an initial successful valvotomy. The attempt failed in 3 patients, 1 of whom had pericardial effusion. Perforation of the pulmonary valve was achieved in 11 patients: 2 with a guidewire and 9 with a radiofrequency guidewire. A subsequent balloon valvuloplasty was performed in these 11 patients. After valvuloplasty, mean right ventricular pressure decreased from 124 +/- 24 to 60 +/- 15 mm Hg (p <0.01). One died of heart failure and infection 10 days later, despite successful weaning from prostaglandin E1. Group I patients (n = 6) were treated with transcatheter valvotomy alone. Group II patients (n = 4) required right ventricular outflow patch. Significant differences between the 2 groups (group I vs II) were identified in tricuspid valve Z value (0.52 +/- 0.37 vs -1.25 +/- 0.48, p <0.05), pulmonary valve Z value (-3.47 +/- 0.59 vs -5.43 +/- 0.94, p <0.05), and ratio of right-to-left ventricular area on the apical 4-chamber view (0.73 +/- 0.06 vs 0.49 +/- 0.03, p <0.05). There were no significant differences in hemodynamic characteristics between the 2 groups. After a follow-up period ranging from 7 to 35 months (mean 18 +/- 10.3), the most recent echocardiograms in the 10 patients showed a mean pressure gradient across the pulmonary valve of 17 +/- 15 mm Hg. All 10 patients had an oxygen saturation of >92%. Transcatheter valvotomy using a radiofrequency guidewire is a safe and effective treatment in selected patients with PA-IVS. Transcatheter valvotomy can be a definitive treatment in PA-IVS patients with a tricuspid valve Z value > or = -0.1, pulmonary valve Z value > or = -4.1 and ratio of right-to-left ventricular area > or = 0.65.     

Transcatheter repair of iatrogenic left ventricular free-wall perforation.

Left ventricular free-wall perforation can complicate catheter-based diagnostic or interventional procedures and may require immediate needle pericardiocentesis followed by surgical repair in about 20% of the cases. We describe the transcatheter closure of a left ventricular free-wall perforation as an option in the event of maintained access to the perforation site after defect creation.     

Initial and late results after catheter intervention for neonatal critical pulmonary valve stenosis and atresia with intact ventricular septum: a technique in continual evolution.

Critical pulmonary valve stenosis or atresia with intact ventricular septum is a rare congenital cardiac defect that can be technically difficult to alleviate in the catheterization laboratory. Over the past 10 years, several techniques and modifications with variable results have been advocated to facilitate the valvuloplasty procedure. This report describes a single operator's experience using various techniques in 28 neonates with critical pulmonary stenosis or atresia who were considered candidates for transcatheter intervention. The first two patients underwent a gradational balloon valvuloplasty approach that resulted in prolonged fluoroscopy exposure. Thereafter, a "snare assisted" umbilical artery approach was developed which facilitated the valvuloplasty procedure and resulted in significantly fewer balloons used and shorter fluoroscopy times. Early in our experience, stiff guidewire perforation of atretic pulmonary valves was used, whereas in our last two patients, a simplified perforation technique with a new 0.9-mm excimer laser catheter was used. Late echocardiographic and clinical follow-up evaluation in 27 patients demonstrates persistent gradient relief, resolution of tricuspid valve insufficiency, and elimination of right to left shunting at the atrial level. Balloon valvuloplasty is the treatment of choice for critical pulmonary valve stenosis or atresia with intact ventricular septum. When necessary, the use of umbilical artery "snare assistance" facilitates the valvuloplasty technique and shortens procedure time while laser perforation is currently preferable for perforation of the atretic pulmonary valve.     

Transcatheter management of neonates with pulmonary atresia and intact ventricular septum

This report describes a 1-day-old infant with valvar pulmonary atresia with intact ventricular septum in whom we were successful in performing transcatheter guidewire perforation and balloon pulmonary valvuloplasty to establish right ventricle-to-pulmonary artery continuity and flow. Also described is implantation of a 4 mm coronary stent into ductus arteriosus in lieu of surgical aortopulmonary shunt to treat pulmonary oligemia and systemic arterial hypoxemia. Details of transcatheter guidewire perforation are presented and it is suggested that this method be used as an alternative to Laser/radio frequency wires, especially in the absence of approval of the latter wires by the regulatory agencies. Stenting of the ductus may be considered an alternative to surgical aortopulmonary shunt. Role of transcatheter technology in the management of selected patients with pulmonary atresia and intact ventricular septum is discussed. Cathet. Cardiovasc. Diagn. 42:395–402, 1997. © 1997 Wiley-Liss, Inc.     

Percutaneous pulmonary valvulotomy using radiofrequency in pulmonary atresia with intact interventricular septum

Early pulmonary valvulotomy in patients with pulmonary atresia and intact interventricular septum allows the development and growth of the right ventricle and two-ventricle circulation. Percutaneous valvulotomy today is a valid alternative procedure to surgical valvulotomy. With the use of the radiofrequency 5F currently available for the treatment of arrythmias atretic pulmonary valve perforation and consecutive balloon dilation may be safely and effectively performed. We describe a case of perforation of a pulmonary valve by radiofrequency in a 15-day-old neonate with pulmonary valve atresia and intact ventricular septum.     

Therapy of HCC-radiofrequency ablation

Radiofrequency interstitial hyperthermia has been used for percutaneous ablation of hepatocellular carcinoma, under ultrasound guidance in local anesthesia. Conventional needle electrodes require a mean number of 3 sessions to treat tumors of diameter < or = 3 cm. Tumors up to 3.5 cm in diameter can be treated in 1 or 2 sessions by expandable needle electrodes. With both methods in all treated cases, ablation of tumors was obtained. In a group of patients with long follow-up, survival rate at 5 years was 40%. In a mean follow-up of 23 months 41% of patients had recurrences (local recurrences in 5%; new lesions in 36%), which often could be retreated by a new course of radiofrequency application. In recent experience large hepatocellular carcinomas (up to 6.8 cm in diameter) were treated by a combination of segmental transcatheter arterial embolization followed by radiofrequency application. In this way most tumors were ablated in one session of radiofrequency therapy. No fatal complications were observed. Major complications were: strong pain due to capsular necrosis in one patient; hemotorax in one case; a fluid collection in the site of ablated tumor in one patient treated by combination of transcatheter arterial embolization and radiofrequency application.     

Subclinical aortic perforation with the infant double-button patent ductus arteriosus occluder.

Modification of the double-button (Sideris) patent ductus arteriosus (PDA) occluder has resulted in a single-strut aortic component rather than the conventional cross-strut design. We report the use of this infant PDA occluder for transcatheter closure in three patients with PDA measuring 2 mm, 3.7 mm, and 4 mm. Subclinical aortic perforation with a small aortic aneurysm developed in two patients 1 year after occluder implantation. The third patient had developed a small aortic aneurysm without perforation at 3-month follow-up. All three patients had a residual shunt and underwent successful PDA surgical closure with aortic aneurysmal repair. Single-strut umbrella designs are not recommended for PDA transcatheter closure.     

A perspective on the ESVEM trial and current knowledge: Catheter ablation for ventricular tachyarrhythmias

Although an effective and potentially curative technique for treating idiopathic ventricular tachycardia, map-guided transcatheter radiofrequency ablation is far from optimal for ventricular tachyarrhythmias in patients with advanced ischemic or other types of organic heart disease. First, this technique can be applied only to a minority of patients with structural heart disease, who can tolerate relatively long episodes of induced ventricular tachycardia necessary for mapping and successful ablation. Second, the success rate is lower and recurrence higher in patients with organic heart disease. Finally, for patients who lose consciousness during tachycardia or who present with prehospital cardiac arrest, transcatheter radiofrequency ablation is inappropriate as definitive treatment. At best, it is palliative and may be used to suppress relatively slow, frequent, or incessant ventricular tachycardias but does not obviate the need for other therpaies such as cardioverter-defibrillator implantation or antiarrhythmic drug therapy.     

Non-invasive stereotactic body radiation therapy for refractory ventricular arrhythmias: an institutional experience

Journal of Interventional Cardiac Electrophysiology - This study evaluated the efficacy and safety of transcatheter radiofrequency ablation (RFCA) in treating ventricular premature contractions...