Pediatric and congenital therapeutic cardiac catheterization

Results of transcatheter closure of the patent ductus arteriosus with the Botallooccluder

OBJECTIVES

Evaluation of the immediate and long-term efficacy of a novel method of transvenous closure of the patent ductus arteriosus was the purpose of this study.

BACKGROUND

In 1981 at the First Moscow Hospital, a new method of transvenous patent ductus arteriosus closure with the Botallooccluder was developed.

METHODS

Transvenous closure of the patent ductus arteriosus with the Botallooccluder was carried out in 273 patients. All patients were regularly followed up as outpatients at intervals of 3, 6 and 12 months after intervention. A total of 171 patients were examined at a mean of 3.2 +/- 1.1 years (range 1 to 8) after the procedure. Late evaluation with cardiac catheterization was performed in 62 patients (36%); 50 (29%) of these 62 also underwent right heart catheterization.

RESULTS

Successful implantation was achieved in 266 patients (97%). The late follow-up findings testify to the favorable clinical course, with disappearance of the continuous murmur and regression of the electrocardiographic signs of ventricular overloading in the vast majority of patients. In no case after complete patent ductus arteriosus closure was a late ductus recanalization observed. No patient had even a minor degree of postprocedural lower extremity venous damage. In 29 patients (24%), the femoral artery was imaged by ultrasonography at late follow-up, without evidence of any vascular abnormality.

CONCLUSIONS

The clinical data suggest high long-term efficacy and reliability of this technique. Introducer sheaths (12F to 16F outer diameter) did not cause any long-term entry site sequelae.

Transcatheter closure of Blalock-Taussig shunts with a modified Rashkind umbrella delivery system

Transcatheter occlusion of Blalock-Taussig shunts was successfully performed in three children with the Rashkind double umbrella occluding device. Complete occlusion was confirmed angiographically in two patients and echocardiographically in the third. The delivery system was adapted for use through smaller sheaths making it more suitable for small children or arterial access.

Transcatheter atrial septal defect occlusion devices: normal radiographic appearances and complications

Three transcatheter atrial septal defect (ASD) occlusion devices have been used in clinical trials during the past decade: the Rashkind ASD occluder, the Lock Clamshell occluder, and the buttoned double-disk device. The normal radiographic appearance of these three devices and radiographic findings in complications are presented. Of 12 transcatheter ASD occlusions performed, the buttoned double-disk device was used in eight patients, the Rashkind ASD occluder in three, and the Lock Clamshell occluder in one. Complications included both improper placement and partial dislodgment of the Rashkind ASD occluder device (n = 2), fracture of a metal arm of the Lock Clamshell device (n = 1), and detachment of the buttoned double-disk device with embolization into the right pulmonary artery (n = 1). Knowledge of the normal radiographic appearance of ASD occlusion devices and the findings in various complications will be necessary for radiologists as transcatheter ASD closure becomes more commonplace. Chest radiography is the primary method of detecting short- and long-term complications in patients following transcatheter ASD closure.

Transseptal catheterization update 1992

Resurgence of the transseptal procedure in the last decade has occurred coincident with the advent of therapeutic catheterizations and in particular mitral balloon vavuloplasty. As larger numbers of these procedures have been performed, experience shows that the position of intended septal puncture varies for each anticipated procedure and need not lie at the fossa ovalis, which is frequently displaced or inaccessible. Recognizing the dynamic alterations in septal and atrial anatomy that accompany the various combinations of valvular heart disease, the experienced interventionalist will use precatheterization echo and radiological techniques to enable precise and localized transseptal puncture. Using these techniques in 597 patients for valvular heart disease, we have had no deaths and a morbidity of 1.8% with the transseptal puncture.

Balloon nitinol device: a new possibility for the fixation of balloons in large arteries

We propose a balloon with nitinol needles for the closure of large vessels avoiding the risk of embolisation. To demonstrate the possibility of application, we utilised a prototype consisting of a polyurethane balloon with one nitinol needle which reached the shape for securing the balloon to the vessel wall after changing the temperature of the device. If further research and experimentation in animals are favorable, it will be possible for the interventional cardiologist to occlude large vessels and perhaps intracardiac shunts easily without danger of embolisation.

Intracardiac echocardiography: current developments

Intracardiac echocardiography refers to the method of imaging cardiac structures from intracardiac locations with the use of ultrasound catheters. Advances in catheter-based interventional cardiologic procedures to treat cardiovascular lesions and the problems encountered during those procedures due to inadequate guidance provided by fluoroscopy have given the impetus to develop other guidance modalities. Experimental explorations with intracardiac ultrasound probes have indicated that detailed visualization of cardiac structures in real-time is possible by intracardiac ultrasound. Recent advances in catheter-based ultrasound technology make it feasible to safely pass small-sized catheters in humans into various intracardiac locations and acquire images of valvular structures and various chambers. Experience with 20 MHz ultrasound catheters indicates that high resolution images of normal and abnormal structures can be obtained if the catheter is manipulated close to the region of interest. The problem of the limited depth of field associated with 20 MHz catheters has led to the fabrication of catheters with lower frequency ultrasound elements. Experimental and clinical experience with 12.5 MHz ultrasound catheters points to the capability and potential of intracardiac echocardiography to not only display normal structures but also aid in the identification of valvular abnormalities, chamber dysfunction and pericardial effusions. In addition, aortic disorders such as acute dissection, coarctation and atherosclerotic disease could be delineated. Similarly, abnormalities involving the pulmonary arteries such as pulmonary embolism, organized thrombi, peripheral pulmonary arterial stenoses, and pulmonary hypertension-induced vascular changes could be recognized. Many modifications in the catheter design are being explored. With further work in the area of catheter technology and ultrasound image processing, intracardiac echocardiography is likely to become a clinical tool.

Real-time, intracardiac, two-dimensional echocardiography: enhanced depth of field with a low-frequency (12.5 mhz) ultrasound catheter

Advances in catheter-based ultrasound imaging technology allow for a unique opportunity to develop two-dimensional intracardiac echocardiography, an imaging method that could have significant clinical applications. In this study, we evaluated the potential of a new, percutaneous, 9-Fr prototype intracardiac echocardiographic catheter with a 12.5-MHz rotating crystal in 13 dogs. In all dogs, we were able to easily advance the intracardiac echocardiographic catheter into the right and left hearts percutaneously and obtain dynamic images of cardiac structures in various imaging planes. With the intracardiac echocardiographic catheter in the right atrium, the whole chamber could be visualized. Minor manipulation allowed visualization of the right atrium, right ventricle, and tricuspid valve in a two-chamber view; further maneuvering yielded four-chamber views. With advancement of the catheter into the right ventricle and pulmonary artery, the right ventricular cavity, right ventricular outflow tract, and pulmonary artery could be imaged. The intracardiac echocardiographic catheter in the aortic root allowed visualization of the pulmonary artery and its bifurcation, superior portions of the atria, interatrial septum, aortic valve, and the proximal left coronary artery. With the intracardiac echocardiographic catheter in the left ventricle, short-axis images of the whole left ventricle were obtained. Manipulating the catheter tip within the left ventricle, we could visualize the left ventricle, left atrium (LA), and the mitral valve in the long axis. We were also able to visualize and identify experimentally-induced ischemic regional left ventricular dyskinesis (four of of five dogs), aortic valvular tear (five out of five dogs), and pericardial effusion with right atrial collapse (two out of two dogs). Intracardiac echocardiography was not associated with any complications. We conclude that percutaneous, low-frequency intracardiac echocardiography with a 12.5-MHz, 9-Fr catheter yields cardiac images in many imaging planes with a good depth of field, allows identification of valvular, myocardial, and pericardial abnormalities, and has excellent clinical potential in the assessment of many cardiovascular disorders.

Left ventricular mid-cavitary obstruction after balloon dilation in isolated aortic valve stenosis in children

A hyperdynamic left ventricle can lead to post-dilation mid-cavitary obstruction in the absence of any preballoon mid-cavitary obstruction in children with aortic valve stenosis. The purpose of this study was to define the incidence and course of post-dilation mid-cavitary obstruction. We reviewed the catheterization and echocardiographic data of 35 patients, ages 3 days to 18 years (mean = 7.9 years), with isolated aortic valve stenosis who underwent balloon dilation with a fall in aortic valve gradient to less than 20 mm Hg. Post-dilation mid-cavitary obstruction was suspected from post-dilation left ventricular angiogram and was quantitated by echocardiographic and Doppler examinations performed immediately after dilation and in a 1-3 month follow-up period. Continuous wave Doppler directed by color flow Doppler was used for evaluation and differentiation of post-dilation mid-cavitary obstruction and residual aortic valve stenosis. Three children (3/35 [9%]) all under 2 years of age developed post-dilation mid-cavitary obstruction immediately after dilation. The obstruction within the cavity resolved spontaneously in all three patients.

CONCLUSIONS

1) Post-dilation left ventricular mid-cavitary obstruction can occur in children under 2 years of age after balloon dilation of severe aortic valve stenosis, and 2) total regression of post-dilation mid-cavitary obstruction occurs spontaneously in all patients.

Doppler ultrasound and the silent ductus arteriosus

A clinically undetectable, small ductus arteriosus was identified by Doppler ultrasonography in 21 individuals. Infants were excluded from the study and no patient had pulmonary hypertension. Persistence of the ductus arteriosus is likely to be more common than shown by less sensitive diagnostic methods. Some patients considered to have infective endocarditis with a normal heart may have a silent ductus arteriosus. Evidence of such an association would justify ligation or antibiotic cover as prophylactic measures.