Abraham Rothman

Percutaneous closure of the small patent ductus arteriosus using occluding spring coils

OBJECTIVES This report summarizes our experience with the use of occluding spring coils to close the small patent ductus arteriosus. BACKGROUND Several patent ductus arteriosus occluders (most notably the Rashkind device) have been developed and studied. Occluding spring coils have been used to close abnormal vessels and vascular connections. We previously reported the use of occluding spring coils to close the small patent ductus arteriosus in a small group of patients. This report describes our series of patients having patent ductus arteriosus closure with occluding spring coils. METHODS Between June 1990 and June 1993, 30 patients underwent cardiac catheterization to have patent ductus arteriosus closure by occluding spring coils. Selection criteria were age > 6 months and narrowest patent ductus arteriosus internal dimension < or = 3.0 mm by color flow imaging. Definitive selection was based on review of aortograms performed at catheterization. A 5.2F coronary catheter was used to deliver one or two standard occluding spring coils. A loop was delivered in the main pulmonary artery, and the remainder of the coil was delivered across the patent ductus arteriosus and into the aortic diverticulum. Patent ductus arteriosus closure was confirmed by aortography or color flow imaging, or both. Follow-up after coil placement occurred at 6 weeks and 6 months and included two-view chest radiography, echocardiography and color flow imaging. RESULTS Of the 30 patients, 29 had successful implantation by one (27 patients) or two (2 patients) occluding spring coils. Of these 29 patients, 19 had a clinically apparent and 10 had a silent patent ductus arteriosus. Average ductus minimal internal dimension was 1.7 mm (range 1.0 to 3.0). Complete closure of the ductus was confirmed in 27 patients by aortography or color flow imaging or both (in 24 within 4 h, in 2 after 6 weeks and in 1 after 6 months). Six weeks after implantation, two patients had a tiny residual patent ductus arteriosus noted on color flow imaging. One patient did not have successful implantation. This patient had a 3.2-mm ductus, and two coils migrated to the distal left pulmonary artery and could not be retrieved. There were no deaths or any significant complications noted during early or late follow-up in these patients. CONCLUSIONS Occluding spring coils may have additional application in closing the small patent ductus arteriosus.

Development and characterization of a cloned rat pulmonary arterial smooth muscle cell line that maintains differentiated properties through multiple subcultures.

BackgroundPulmonary hypertension is associated with abnormal pulmonary arterial contractility and growth. The mechanisms for these abnormalities are largely unknown. To study these processes, we sought to develop an in vitro system. Even though cultured aortic and pulmonary artery smooth muscle cells (SMCs) have been of considerable value in studying smooth muscle biology, one drawback of this system has been that these cells often lose differentiated properties in an unpredictable manner when they are passaged in culture. In addition, there appear to be significant differences in physiological and pathological responses between the systemic and pulmonary circulations, many of which could be directly related to the smooth muscle. We therefore established a cloned population of rat pulmonary arterial SMCs (PASMCs) that maintain differentiated properties through multiple subcultures. Methods and ResultsPASMCs were obtained initially by enzymatic dissociation from pulmonary arteries of adult Sprague-Dawley rats. From these cells, clones were isolated. The cloned cells retained expression of functional surface receptors for angiotensin II, norepinephrine, and α-thrombin and high levels of the smooth muscle isoforms of α-actin, myosin heavy chain, myosin regulatory light chain, and α-tropomyosin mRNAs even after multiple passages. The cells could also be transfected and processed exogenous transcripts in a smooth muscle-specific fashion. ConclusionsThese cloned PASMCs retain many differentiated characteristics and should be valuable for future studies of pulmonary vascular smooth muscle cell biology.

ATRIAL SEPTOSTOMY FOR PULMONARY HYPERTENSION

Atrial septostomy represents an additional, promising strategy in the treatment of severe PPH. Experience with this procedure still is limited; however, based on analyses of the worldwide experience, several general conclusions and recommendations can be made. 1. Atrial septostomy can be performed successfully in selected patients with advanced pulmonary vascular disease. 2. Patients with primary pulmonary hypertension who have undergone successful AS have shown: a significant clinical improvement beneficial and long-lasting hemodynamic effects at rest a trend toward improved survival 3. The procedure-related mortality of the collective experience is high (16%). Several recommendations can be made to minimize the risk: [figure: see text] Atrial septostomy should be attempted only in institutions with an established track record in the treatment of advanced pulmonary hypertension, where septostomy is performed with low morbidity. Atrial septostomy should not be performed in patients in whom death is impending or who have severe right ventricular failure and are on maximal cardiorespiratory support. An mRAP greater than 20 mm Hg, PVR index greater than 55 u/m2, and a predicted 1-year survival less than 40% are significant predictors of procedure-related death. Before cardiac catheterization, patients should have an acceptable baseline systemic oxygen saturation (> 90% in room air) and optimized cardiac function (adequate right heart filling pressure, additional inotropic support if necessary). During cardiac catheterization, the following are mandatory: Supplemental oxygen Mild sedation to prevent anxiety Careful monitoring of variables (left atrial pressure, SaO2, and mRAP) Step by step procedure After AS, it is important to optimize oxygen delivery. Transfusion of packed red blood cells or erythropoietin (before and following the procedure, if needed) may be necessary to increase oxygen content. 4. Because the disease process in PPH is unaffected by the procedure (late deaths), the long-term effects of an AS must be considered to be palliative. 5. Despite its risk, AS may represent a viable alternative for selected patients with severe PPH. Indications for the procedure may include: Recurrent syncope or right ventricular failure, despite maximal medical therapy, including oral calcium-channel blockers or continuous intravenous prostacyclin (Fig. 11) As a bridge to transplantation When no other option exists.

Atrial septostomy as a bridge to lung transplantation in patients with severe pulmonary hypertension

Long waiting times for lung transplantation have limited the survival of patients with advanced pulmonary hypertension. Atrial septostomy has been used in this group of patients in an attempt to prolong survival. We evaluated the results of atrial septostomy in 12 patients using the static graded balloon dilation technique. Between December 1990 and May 1998, 10 women and 2 men (ages 13 to 56 years, mean 37 years) underwent atrial septostomy. Nine patients had primary and 3 patents had secondary pulmonary hypertension. Five patients deteriorated despite long-term intravenous prostacyclin infusions. The atrial septum was crossed with a Brockenbrough needle, followed by an 0.035-J exchange wire and progressively larger catheter balloons for atrial septal dilation, until systemic oxygen saturation decreased 5% to 10%. An atrial septal defect was successfully created in each patient. The mean right atrial pressure decreased from 23 to 18 mm Hg and the mean systemic oxygen saturation decreased from 93% to 85%. The mean cardiac index increased from 1.7 to 2.1 L/min/m2 and the mean systemic oxygen transport increased from 268 to 317 ml/min/m2. Complications occurred in 3 patients: transient hypotension during transesophageal echocardiography, a femoral pseudoaneurysm, and a femoral arteriovenous fistula. After septostomy, 6 patients had clinical improvement (resolution of ascites, edema, and no further episodes of syncope); 5 of these 6 patients underwent lung transplantation a mean of 6.1 months after septostomy. Six patients did not have clinical improvement after septostomy. Atrial septostomy improves the hemodynamic status and may be useful as a bridge to lung transplantation in selected patients with pulmonary hypertension.

Acute and follow-up intravascular ultrasound findings after balloon dilation of coarctation of the aorta.

The study objective was to examine the vascular wall changes caused by balloon dilation of coarctation of the aorta (CoA) acutely and at short-term follow-up using intravascular ultrasound imaging. Intravascular ultrasound has been valuable in assessing the vessel wall changes in coronary and peripheral arteries after balloon dilation, often with more detail than angiography. Methods and ResultsIntravascular ultrasound imaging, using 4.8F, 20-MHz or 6.2F, 12.5-MHz catheters on either Diasonics or HP scanners, was performed in 17 patients during balloon angioplasty for native (n=12) and recurrent (n=5) CoAs. Nine patients were also studied at the time of follow-up cardiac catheterization 28.1±18.0 months after angioplasty. Immediately after dilation, the mean pressure gradient across the CoA decreased from 42.9±16.4 to 9.0±5.4 mm Hg (P < .001) and the mean diameter of the coarcted segment increased from 4.4±1.9 to 7.9±2.4 mm (P < .001). An intimal tear or flap was noted by ultrasound in 12 of the 12 native CoAs and 4 of the 5 recoarctations. In contrast, only 6 of the native CoAs and 2 of the recoarctations had an intimal flap or dissection detected by angiography. At follow-up, the residual pressure gradient did not significantly change from that measured immediately after dilation, but the CoA diameter increased from 7.8±1.5 to 9.9±2.3 mm (P < .01). No aneurysms were detected. Four of the 9 patients showed ultrasonic and angiographic evidence of healing and remodeling with diminution in size or disappearance of the intimal tears. ConclusionsThere is a high incidence of intimal tears and dissections immediately after balloon angioplasty for native and recurrent CoAs. Intravascular ultrasound is more sensitive than angiography in detecting the vascular wall changes. Even significant intimal tears are not necessarily associated with aneurysm formation, and many decrease in size or disappear at short-term follow-up.

Stretch increases inositol trisphosphate and inositol tetrakisphosphate in cultured pulmonary vascular smooth muscle cells

There are no reports of the effect of stretch on inositol phosphates in smooth muscle. Phosphoinositide and inositol phosphate metabolism was studied in cultured rat vascular smooth muscle cells subjected to stretching. The masses of inositol trisphosphate and tetrakisphosphate increased (+34 +/- 7% and +58 +/- 12%, respectively; p less than 0.001) after 25 s of a single 20% stretch and had returned to control levels by 45 s; phosphatidylinositol, phosphatidylinositol phosphate and bisphosphate did not change. Repetitive stretch did not alter the masses of any of the compounds. A single stretch also increased 45Ca2+ efflux (+52 +/- 5%, p less than 0.01). These data suggest that stretch of cultured vascular smooth muscle can elicit a rapid, short-lived increase in inositol phosphates, which may subsequently affect Ca2+.

Percutaneous coil embolization of superfluous vascular connections in patients with congenital heart disease

Transcatheter Gianturco coil embolization of 26 superfluous but hemodynamically significant vascular connections was attempted in 19 patients with congenital heart disease. There were 18 aortopulmonary collaterals, two vessels involved in pulmonary sequestration, two surgical aortopulmonary shunts (one inadvertently connected from the left subclavian artery to a left upper pulmonary vein), two cases of patent ductus arteriosus, one regurgitant left ventricular-to-descending aorta conduit, and a left superior vena cava-to-left atrium post Fontan procedure. The mean ratio of coil to vessel diameter was 1.6 +/- 0.7, and a mean of 1.5 +/- 1.1 coils were used per vessel. Occlusion was achieved in 24 of 26 attempts (92%), being complete in 21 (81%) and near complete (> 80% decrease in flow) in three (12%). Two attempts failed; a tortuous aortopulmonary collateral was engaged by the delivery catheter but the coil could not be advanced past an acute angle, and another aortopulmonary collateral had a narrow origin and enlarged distally, resulting in coil migration to a distal pulmonary artery branch. One patient had a transient decrease in leg pulses that resolved spontaneously. Fever occurred in four patients (21%) within 12 hours of coil placement, and resolved in all without sequelae or complications. A variety of undesirable vascular connections in patients with congenital heart disease can be safely and effectively treated by percutaneous coil embolization.

Surgical Management of Subaortic Obstruction in Single Left Ventricle and Tricuspid Atresia

Subaortic obstruction caused by either a restrictive bulboventricular foramen in single left ventricle with an outflow chamber or by a restrictive ventricular septal defect in tricuspid atresia with transposition of the great arteries can lead to a hypertrophied, noncompliant ventricle and excessive pulmonary blood flow. This combination is disadvantageous to potential Fontan procedure candidates because they are dependent on good ventricular function and low pulmonary vascular resistance for survival. The results of surgical procedures to directly or indirectly relieve significant subaortic obstruction (gradient greater than 30 mm Hg) in 24 patients, 16 with single left ventricle and 8 with tricuspid atresia, were reviewed. Four patients had a left ventricular apex to descending aorta valved conduit; none survived. Seven patients had resection of subaortic tissue; four survived and four developed heart block at surgery. Adequate gradient relief was evident in only one of the four survivors. Thirteen patients had a main pulmonary artery to ascending aorta anastomosis or conduit; six survived. All survivors had adequate gradient relief. The overall survival was 42% (10 of 24). None of seven patients with a subaortic gradient greater than 75 mm Hg survived. These data show that: Surgical relief of established subaortic obstruction in patients with single left ventricle and tricuspid atresia carries a high mortality rate, especially if the subaortic gradient is greater than 75 mm Hg. The best procedure appears to be the pulmonary artery to ascending aorta anastomosis. A clearer understanding of the factors leading to the development of significant subaortic obstruction is necessary to prevent it or to devise improved therapeutic strategies.

Percutaneous coil occlusion of patent ductus arteriosus

OBJECTIVE To determine the success rate and safety of percutaneous patient ductus arteriosus (PDA) coll occlusion. DESIGN Thirty consecutive pediatric patients with small to moderate-size PDAs (minimum diameter < or = 4 mm) underwent percutaneous coll occlusion. The results were assessed by angiography and echocardiography. The mean age was 5.1 +/- 4.2 years (range, 0.8 to 18.8 years); mean weight was 19.2 +/- 10.3 kg (range, 8.1 to 40.0 kg). The mean minimum diameter of the PDA was 1.8 +/- 0.8 mm (range, 1.0 to 4.0 mm). RESULTS PDA occlusion was achieved with one coil in 24 patients, 2 coils in 3 patients and 3 coils in 3 patients. The mean coil/PDA diameter ratio was 2.5 +/- 0.5. Immediately after coil occlusion, 29 PDAs had no flow by anglography; one had a small residual shunt. There were no significant complications. In the first 24 hours after coil implantation, echocardiography showed complete occlusion in 28 patients, a small left-to-right shunt in the same patient that had a residual shunt by anglography, and a trace shunt in one additional patient. In the two patients with residual flow by echocardiography, follow-up ultrasonography revealed no residual shunt 1 and 3 months later. At a mean follow-up of 11.8 +/- 9.3 months (range, 0 to 36.0 months), there was no PDA flow by color Doppler echocardiography in any of the 30 patients. CONCLUSION Coil occlusion is a safe and effective method of percutaneous closure of small to moderate-size PDAs. The largest PDA that can be closed with this technique remains to be determined.

Balloon angioplasty of native aortic coarctation in infants 3 months of age and younger.

The use of balloon dilation to treat native aortic coarctation is controversial, particularly in infants. Between January 1991 and September 1996, 12 patients < or = 3 months of age with native coarctation of the aorta (CoA) underwent balloon angioplasty (BA). All 12 lesions were dilated successfully with a mean reduction in peak systolic gradient from 49.3 +/- 16.5 mm Hg to 6.8 +/- 4.0 mm Hg (p < 0.001) and a mean increase in minimum CoA diameter from 2.4 +/- 0.6 mm to 5.5 +/- 1.3 mm (p < 0.001). Intimal flaps or tears were detected immediately after BA in 4 (33%) of 12 patients by angiography and in 8 (89%) of 9 patients by intravascular ultrasonography. No deaths or major complications related to the BA occurred. One patient had documented asymptomatic femoral artery obstruction, and one patient with hydrops fetalis and congenital pleural effusions died with gram-negative sepsis 1 week after the procedure. Follow-up was available for 10 patients (1 was lost to follow-up) between 2 months and 4.1 years (mean 2.4 +/- 1.3 years) after BA. No patient had an aortic aneurysm. Restenosis occurred in 5 (50%) of 10 patients, requiring reintervention a mean of 2.6 +/- 2.1 months after BA. One patient underwent surgical repair. Repeat BAs were performed in the other four patients; three were successful, and one with partial gradient relief required surgical repair. Five patients have not required reintervention a mean of 2.9 +/- 1.0 years after the initial BA. Among these five patients, follow-up intravascular ultrasound performed in three patients a mean of 2.0 +/- 1.9 years after BA showed favorable endovascular remodeling. There was a tendency for early reintervention in patients < 1 month of age and coexistence of a patent ductus arteriosus at the time of BA. In conclusion, selected infants < or = 3 months of age with discrete native CoA may be treated initially with balloon dilation. Most patients who have restenosis respond successfully to repeat BA.