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Biomedical subjects

Larry A Latson

Publications and source records attributed to Larry A Latson.

17 recordsLinked to original sources

Use of a straight, side-hole delivery sheath for improved delivery of Amplatzer ASD occluder.

The Amplatzer ASD occluder may be difficult to position in some patients with a large atrial septal defect (ASD) or deficiency of one or more atrial septal rims. We developed a method to modify a Mullins transseptal sheath to enhance delivery. The resulting sheath is straight and has an exit orifice essential in the side of the distal portion of the sheath-a straight, side-hole (SSH) delivery sheath. We have used this modified delivery sheath in 140 successive patients with excellent results. The techniques of sheath modification and delivery of the device using the modified sheath are described.

Balloon Occlusion↗

Atrial septostomy using a butterfly stent in a patient with severe pulmonary arterial hypertension.

We describe a patient with severe pulmonary artery hypertension and refractory right heart failure who underwent "butterfly" stent atrial septostomy guided by intracardiac ultrasound. This technique may be superior to previously reported blade and balloon septostomy because it allows creation of an atrial septal defect of a precise predetermined diameter. The patient's systemic blood flow and clinical status improved significantly after the procedure, allowing her to be accepted as a candidate for lung transplantation.

Adult↗

Analysis of factors related to successful transcatheter closure of secundum atrial septal defects using the HELEX septal occluder.

BACKGROUND: The HELEX septal occluder is a new transcatheter atrial septal defect occlusion device. This study analyzes the data collected from the first US clinical trials with this device to determine the most significant factors in successful use of the device. METHODS: Tables of subsets of data were constructed in categories of possibly significant patient and device variables compared with important outcomes. Chi2 analysis was used to determine which variables had significant impact on outcomes. RESULTS: The device was successfully implanted in 87% of patients (298/342). A major adverse event occurred in 5.8% (mostly device removal for various reasons). A significant residual leak persisted at 1 year in 2.6%. A fracture of the wire frame occurred in 8%--all were asymptomatic and only 1 required treatment. Overall composite success (no significant leak and no major adverse event) was seen in 91.5%. Patient age, body surface area, and device size had no significant influence on outcomes, except that wire frame fractures were more likely with the 35-mm device. Defect stretch diameter had the largest influence on outcomes, and implantation was possible in only 67% if the stretched diameter of the defect was >20 mm. Device-defect ratio also had a significant effect on delivery success and composite success. CONCLUSIONS: The HELEX septal occluder is best suited for small to moderate atrial septal defects with a stretch diameter <20 mm. Although composite success was achieved in 80% of patients when a device-defect ratio <1.6 was necessitated or elected, use of a device that provided a ratio >2 resulted in 95% composite success, and is recommended when possible.

Cardiac Catheterization↗

Selective timing for the arterial switch operation.

BACKGROUND: To determine outcomes for the arterial switch operation individualized according to the underlying anatomy and clinical status. METHODS: A retrospective review of a consecutive series of infants less than 90 days of age who underwent the arterial switch operation at a single institution. RESULTS: From July 1993-April 2001, 117 infants underwent an arterial switch operation before 90 days of age. Seventy-five patients (64%) had transposition of the great arteries with intact ventricular septum with the aim of operation before 14 days of age; however, 8 of these patients had delayed presentation (range 15-46 days). Thirty-five patients (30%) had transposition with a ventricular septal defect (30 patients) or double outlet right ventricle (5 patients) and normal arch anatomy and were repaired within the first 90 days of life depending on the severity of heart failure at a median of 12 days of age (range 3-83 days). Seven patients (6%) had associated aortic coarctation (5 patients) or interrupted aortic arch (2 patients). One patient died during hospitalization (0.85% hospital mortality) and one patient died from noncardiac causes during a median follow-up of 35 months (1.7% total mortality). Four patients required intervention during follow-up (3.4%) for new aortic coarctation (2 patients), supravalvar pulmonic stenosis (1 patient), or right hemi-diaphragm paralysis (1 patient). CONCLUSIONS: Individualized timing for the arterial switch operation within the first ninety days of life produces excellent survival rates for all types of transposition physiology with the expectation of a satisfactory course during follow-up.

Coronary Vessel Anomalies↗

Intracardiac echocardiography during transcatheter interventions for congenital heart disease.

Although transesophageal echocardiography is often used for guidance during transcatheter interventions, few data exist regarding the use of the newer modality of intracardiac echocardiography. This brief report summarizes our single center experience using intracardiac echocardiographic guidance during transcatheter interventional procedures for congenital heart disease.

Adolescent↗

Initial experience in Brazil with the Helex septal occluder for percutaneous occlusion of atrial septal defects.

OBJECTIVE: To evaluate the initial clinical experience with the Helex septal occluder for percutaneous closure of atrial septal defects. METHODS: Ten patients underwent the procedure, 7 patients with ostium secundum atrial septal defects (ASD) with hemodynamic repercussions and 3 patients with pervious foramen ovale (PFO) and a history of stroke. Mean age was 33.8 years and mean weight was 55.4 kg. Mean diameter by transesophageal echocardiography and mean stretched ASD diameter were 11.33 3.3mm, and 15.2 3.8mm, respectively. The Qp/Qs ratio was 1.9 0.3 in patients with ASD. RESULTS: Eleven occluders were placed because a patient with 2 holes needed 2 devices. It was necessary to retrieve and replace 4 devices in 3 patients. We observed immediate residual shunt (< 2mm) in 4 patients with ASD, and in those with patent foramen ovale total occlusion of the defect occurred. No complications were noted, and all patients were discharged on the following day. After 1 month, 2 patients with ASD experienced trivial residual shunts (1mm). In 1 patient, we observed mild prolapse in the proximal disk in the right atrium, without consequences. CONCLUSION: The Helex septal occluder was safe and effective for occluding small to moderate atrial septal defects. Because the implantation technique is demanding, it requires specific training of the operator. Even so, small technical failures may occur in the beginning of the learning curve, but they do not involve patient safety.

Adolescent↗

Transcatheter angioplasty for acquired pulmonary vein stenosis after radiofrequency ablation.

BACKGROUND: Pulmonary vein stenosis has recently been recognized as a complication of radiofrequency ablation for atrial fibrillation. This study evaluates the presentation of affected patients and the role of transcatheter therapy for this patient population. METHODS AND RESULTS: This study used a retrospective review of data from 19 patients (age, 51+/-13 years) with pulmonary vein stenosis who underwent catheterization and angiography between December 2000 and December 2002. Quantitative perfusion and spiral CT scans were performed for initial diagnosis and follow-up. The median duration between radiofrequency ablation and the reported onset of respiratory symptoms for 18 of 19 patients was 7.5 weeks (0.1 to 48). After the onset of symptoms, all but two patients were initially misdiagnosed with a symptoms-to-diagnosis duration of 16 weeks (2-59). At initial catheterization, 17 of 19 patients had angioplasty in 30 veins with stent placement in 5 vessels when a flap occurred. Overall vessel diameter increased from 2.6+/-1.6 to 6.6+/-2.4 mm (P<0.0001). There were 4 procedure-related adverse events but no long-term sequelae. Immediate follow-up showed improved flow to involved lung segments. At a median follow-up of 43 weeks (2-92), although repeat angioplasty for restenosis was necessary in 8 of 17 patients, 15 of 17 patients currently have no or minimal persistent symptoms. CONCLUSIONS: Pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation is often misdiagnosed. Although further follow-up is necessary to determine long-term success, our data indicate better pulmonary vein flow and symptomatic improvement in the majority of patients undergoing dilation of postablation pulmonary vein stenosis.

Angioplasty, Balloon↗

Invasive echocardiography: the use of catheter imaging by the interventional cardiologist.

Ultrasound imaging is frequently used for diagnostic purposes or guidance during procedures in the pediatric and congenital cardiac catheterization laboratory. As new imaging modalities emerged, many interventional cardiologists rather than noninvasive specialists are now performing the ultrasound imaging as part of the catheterization. The focus of this discussion will be to detail the technique and application of echocardiography by the interventional cardiologist.

Cardiac Catheterization↗

The Genesis stent: A new low-profile stent for use in infants, children, and adults with congenital heart disease.

Placement of intravascular stents that can reach adult size in infants and smaller children has been limited by the large profile and poor flexibility of currently available stents. In vitro and in vivo testing of the Genesis stent was performed to evaluate crimpability, predeployment flexibility, and radial strength. Comparisons were made to the Palmaz iliac and IntraStent (IS) LD stents. Nine physicians placed 30 Genesis stents in swine pulmonary and systemic arteries to evaluate stent deliverability/crimpability. Two swine were recovered and underwent a second catheterization 8 weeks later, where the stents (n = 8) were reexpanded to maximal size. Angiographic and intravascular ultrasound (IVUS) assessments were performed. In vitro testing revealed the Genesis stent to have superior crimpability, flexibility, and comparable radial strength to the Palmaz iliac stent, and superior crimpability and radial strength and comparable flexibility to the IS LD series. During in vivo testing, the physicians graded the Genesis stent superior to the Palmaz stent regarding crimpability and deliverability, and superior to the IS LD stent in regard to crimpability, and comparable to or superior in deliverability. In the chronic animals, the Genesis stent was expanded up to maximal diameter 8 weeks following implantation. Angiographic and IVUS revealed no fractures no in-stent restenosis. The Genesis stent can be easily delivered through smaller sheaths, which will facilitate their use in infants and smaller children with vascular stenosis.

Adult↗

Transcatheter interventions across an inferior vena cava filter.

Patients who suffer from an embolic event often undergo placement of an inferior vena caval filter. Few data are available regarding treatment of this patient population with concurrent right-to-left shunting across an atrial communication. We report four cases of transcatheter device closure of an atrial communication across an inferior vena cava filter.

Aged↗

Staged repair of tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries.

OBJECTIVE: To assess the results of a staged surgical approach for tetralogy of Fallot with pulmonary atresia, hypoplastic or absent pulmonary arteries, and major aortopulmonary collateral arteries. METHODS: We retrospectively reviewed a consecutive series of these patients from a single institution. RESULTS: From July 1993 to April 2001, 46 consecutive patients with tetralogy of Fallot, pulmonary atresia, and major aortopulmonary collateral arteries were treated with staged surgical repair. The operative sequence usually began with a central aortopulmonary shunt followed by unifocalization of aortopulmonary collateral arteries depending on the source and distribution of pulmonary blood flow. Twenty-eight patients (61%) subsequently underwent complete repair with ventricular septal defect closure and right ventricle to pulmonary artery connection. Those patients who underwent complete repair had a median of 3 total operations (range 1-6). The ratio of the mean pulmonary artery pressure to the mean systemic blood pressure at the time of complete repair was 0.36 (range 0.19-0.58). Two of the 28 repaired patients (7.1%) required subsequent fenestration of the ventricular septal defect closure due to later development of supersystemic right ventricular pressure and right ventricular failure. Eighteen patients (39%) have undergone 1 or more staging operations and are considered good candidates for eventual complete repair. There were no hospital deaths. There was 1 late death (2.2%; 95% CI 0.4-11.3%) in a patient born prematurely who developed severe bronchopulmonary dysplasia precluding complete repair. CONCLUSIONS: For tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries, a staged surgical approach yields low overall mortality and acceptable hemodynamics after complete repair.

Abnormalities, Multiple↗

Results of the double switch operation for congenitally corrected transposition of the great arteries.

OBJECTIVE: To determine the outcomes for a program that utilizes the double switch operation as the primary approach for congenitally corrected transposition. METHODS: The records of 46 consecutive patients from a single institution who had undergone a double switch operation from October 1993 to March 2002 were reviewed. The records of 24 patients who were evaluated during the same period and felt not to be candidates for the double switch operation or who are awaiting double switch after pulmonary artery banding were also reviewed. RESULTS: The median age at operation was 28 months (range 2 months to 16.3 years). Associated defects included ventricular septal defect 40, pulmonic stenosis 13 and pulmonary atresia 16. Twenty-six patients underwent an arterial switch operation combined with a Senning procedure while 20 patients underwent combined Rastelli and Senning procedures. Before the double switch, 12 patients had required pulmonary artery banding and 21 patients had systemic to pulmonary artery shunts. The median duration of stay in the intensive care unit was 3.5 days (range 2-60 days) and the median duration of total hospital stay was 8 days (range 5-60 days). There were no hospital deaths; one patient died 5 months after discharge due to an arrhythmogenic cardiac arrest during a median follow-up of 24 months [long-term survival 98% (95% CI 89-100%)]. CONCLUSIONS: The double switch operation may be performed with excellent hospital and long-term survival. The theoretical advantages of this procedure which enables the morphologic left ventricle and mitral valve to support a systemic pressure load must be established by careful follow-up of these patients.

Adolescent↗

Cutting balloon angioplasty for children with small-vessel pulmonary artery stenoses.

Patients with complex congenital heart disease may have pulmonary artery stenoses that are either congenital or associated with scarring following surgical procedures. This study evaluates cutting balloon angioplasty for small-vessel pulmonary artery stenoses resistant to standard balloon angioplasty. Between October 1998 and December 1999, patients were enrolled in an FDA-approved compassionate-use protocol. During four catheterizations, there were seven lesions found resistant to standard balloon angioplasty (mean lesion diameter was unchanged: 1.8 mm +/- 0.8 mm to 1.9 +/- 0.8 mm). A cutting balloon was inflated twice in each of these lesions. Standard balloon angioplasty was then repeated. Final mean lesion diameter was increased significantly (1.9 mm +/- 0.8 mm to 3.8 +/- 1.3 mm; P <or= 0.01). Follow-up catheterizations performed a median of 14 months later showed only slight decrease in mean lesion diameter (3.2 +/- 1.2 mm), still significantly greater than initial mean lesion diameter (P < 0.03). In conclusion, cutting balloon angioplasty for pulmonary artery stenoses resistant to standard balloon angioplasty improves the immediate and intermediate term results of angioplasty for these lesions.

Angioplasty, Balloon↗