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Biomedical subjects

C E Mullins

Publications and source records attributed to C E Mullins.

At least 55 records · Page 3Linked to original sources
PubMed1996

Transcatheter closure of the patient ductus arteriosus in adults using the Gianturco coil.

BACKGROUND AND HYPOTHESIS: Although results of surgical ligation of the patent ductus arteriosus (PDA) in the pediatric age group are excellent, surgical management of the adult with a PDA may be more problematic. The PDA that presents in adulthood may be calcified and friable, rendering simple ligation via a thoracotomy difficult, inadequate, and hazardous. Patch closure of the ductus arteriosus from either the aortic or pulmonary artery orifice using cardiopulmonary bypass or transient aortic cross-clamping is necessary but increases surgical risk. Furthermore, older patients with diseases unrelated to their PDA and patients with Down's syndrome may have higher risks with intubation, general anesthesia, and surgery. Early results of percutaneous transcatheter occlusion of the PDA with Gianturco coils performed under sedation and local anesthesia are promising. METHODS: Six adults with mean age of 39.1 years (range 23.1-62.0 years) were found to have an isolated PDA with mean minimum diameter of 2.7 mm (range 1.0-5.0 mm) at cardiac catheterization. All underwent percutaneous transcatheter occlusion of the PDA using Gianturco coils. RESULTS: Coil implantation was successful in all patients. There were no complications and all were discharged home within 24 hours. Complete ductal occlusion was seen immediately in 4 of 6 patients (67%) while 2 of 6 (33%) had small residual leaks. However, complete occlusion was achieved in all patients by 6 months following the procedure. CONCLUSION: Transcatheter occlusion of the PDA using coils is safe and efficacious in adults.

Adult↗
PubMed1995

Repeat dilation of intravascular stents in congenital heart defects.

BACKGROUND: Intravascular (Palmaz) stents have been successfully implanted in patients with congenital and acquired branch pulmonary stenosis. Early results are excellent; however, there is no information on restenosis and repeat dilation in patients with congenital heart disease. The purpose of this study is to review the incidence of restenosis and demonstrate the safety and efficacy of repeat dilation of stents in this group of patients. METHODS AND RESULTS: Of 94 patients with 163 implanted stents in this single-center study, 43 patients with 73 implanted stents underwent recatheterization. Only 2 of 73 restudied stents (3%) developed significant restenosis. In 20 patients, 30 stents were redilated. At stent implantation, the mean age of this subgroup was 14.2 years, the mean intraluminal diameter increased from 4.9 to 10.7 mm (P = .0001), and the systolic gradient (mean) across the stent decreased from 52 to 11 mm Hg (P = .0001). At recatheterization (mean, 13 months), all stents were patent. The mean diameter decreased by 1.2 mm (P = .0001), but the increase in the gradient (mean, 3 mm Hg) was not significant (P = .11). After repeat dilation, the diameter increased from 9.5 to 12.2 mm (P = .0001), and the gradient decreased from 14 to 8 mm Hg (P = .0003). The 2 stents with restenosis were redilated successfully. Two patients underwent a successful second redilation of 3 stents at 18 and 26 months. There were no complications. CONCLUSIONS: All stents remained patent. The occurrence of significant restenosis is low (3%), and these restenoses can be redilated and/or restented. Repeat dilation of the Palmaz stent implanted in branch pulmonary artery stenosis can be performed with safety and efficacy (94% success rate) up to 3 years after stent implantation.

Adolescent↗
PubMed1995

Use of intravascular stents in systemic venous and systemic venous baffle obstructions. Short-term follow-up results.

BACKGROUND: Balloon-expandable intravascular stents are well accepted in the management of arterial obstructions. This study was undertaken to detail the immediate and short-term results of intravascular stent implantation in systemic venous and systemic venous baffle obstructions in children. METHODS AND RESULTS: Between September 1991 and June 1994, 12 patients had 21 stents implanted in 13 systemic venous obstructions, 1 patient having stents placed in 2 separate obstructions. In the baffle group, 4 of 13 obstructions were at the superior vena cava/right atrial junction after atrial baffling for transposition of the great arteries. One of 4 patients had complete obstruction requiring transseptal needle perforation before stent implantation. There was an immediate gradient reduction from 12 +/- 8.4 mm Hg (range, 4 to 20 mm Hg) to 1.3 +/- 1.9 mm Hg (range, 0 to 4 mm Hg, P = .05). The obstructed segment diameter increased from 3.5 +/- 3.9 mm (range, 0 to 8.5 mm) to 16 +/- 2.7 mm (range, 14 to 20 mm, P = .002). In the central vein group, 9 of 13 obstructions were in large central veins. Three of 9 patients had complete obstruction requiring transseptal needle perforation before stent implantation. There was an immediate gradient reduction from 10.3 +/- 8.5 mm Hg (range, 0 to 20 mm Hg) to 0.8 +/- 1.1 mm Hg (range, 0 to 3 mm Hg, P = .005). The obstructed segment diameter increased from 1.3 +/- 1.1 mm (range, 0 to 2.8 mm) to 9.4 +/- 1.7 mm (range, 7.6 to 12 mm, P < .001). There were no acute complications in either group. In the follow-up group, patients were scheduled for clinical follow-up at 3, 6, and 12 months with echocardiography or magnetic resonance imaging (MRI) at 3 or 6 months and for repeat cardiac catheterization at 12 months. All stents were patent by echocardiography or MRI when studied at follow-up. Cardiac catheterization in 6 of 12 patients, 2 to 13 months after stent, demonstrated that all stents remained patent without compression or fracture. Follow-up and immediate poststent gradients were not significantly different (1 +/- 1.6 versus 0.7 +/- 1.2 mm Hg, P = NS). Neointimal hyperplasia (5 of 6 patients) reduced the stent lumen only from 12.5 +/- 4.7 mm (range, 8 to 20 mm) to 10.6 +/- 4.7 mm (range, 4.5 to 17.7 mm, P = NS). No stents required redilation. One of 18 stents placed in series had "unlocked" and rotated in the venous lumen but remained fully patent to flow. CONCLUSIONS: Balloon-expandable intravascular stents can be safely and effectively used to relieve systemic venous and systemic venous baffle obstructions, even when obstruction is complete. Short-term follow-up suggests excellent continued patency, but further follow-up is required to observe for progression of neointimal hyperplasia. We postulate that balloon-expandable intravascular stents will become the treatment of choice for the relief of selected systemic venous and venous baffle obstructions in the pediatric population.

Adolescent↗
PubMed1995

New Gianturco-Grifka vascular occlusion device. Initial studies in a canine model.

BACKGROUND: Transcatheter closure of cardiovascular defects remains a challenge. Several occlusion devices are available, but each device has limitations. The purpose of this study was to evaluate the new Gianturco-Grifka vascular occlusion device (GGVOD) in a canine model. METHODS AND RESULTS: A total of 26 GGVODs were implanted as part of short- and long-term studies. In the short-term study, 1 GGVOD was implanted in each of 11 systemic arteries from 3.2 to 9.0 mm in diameter. All 11 arteries were occluded immediately. In the long-term study, an aortopulmonary shunt was placed in 10 dogs (9, Gore-tex graft; 1, subclavian artery) followed by GGVOD implantation; additionally, a GGVOD was implanted in 5 subclavian arteries. The dogs were boarded for 3 to 6 months, then recatheterized and euthanatized. Immediately after implantation, the 5 subclavian arteries and 9 Gore-tex shunts were occluded completely; the 1 subclavian artery shunt had a small residual leak. At recatheterization, all 10 shunts and 5 subclavian arteries were occluded completely. Necropsy revealed all shunts to be occluded, with the aortic and pulmonic orifices covered with a neointimal layer. The mean fluoroscopic time needed for GGVOD implantation was 9 minutes (range, 3 to 22 minutes). CONCLUSIONS: (1) In a canine model, the GGVOD is effective for transcatheter occlusion of arteries and aortopulmonary shunts from 3 to 9 mm in diameter. Possible indications in children include aortopulmonary collateral vessels, long patent ductus arteriosus, systemic-pulmonary shunts, AV malformations, and arteries supplying tumors. (2) GGVOD implantation requires a short fluoroscopic time.

Animals↗
PubMed1995

Balloon angioplasty of native coarctation of the aorta: midterm follow-up and prognostic factors.

UNLABELLED: OBJECTIVES, This retrospective analysis was designed to examine the intermediate and long-term effects of balloon angioplasty for native coarctation of the aorta and to determine whether any factors are predictive of outcome. BACKGROUND: Balloon angioplasty for native coarctation of the aorta is controversial. Concerns exist over lack of long-term follow-up and possible formation of aneurysms. The role of transverse arch and isthmus hypoplasia after balloon dilation is unknown. METHODS: Included in the study were all patients 3 days to 29 years old (mean age 4.6 years) referred for possible balloon dilation to the pediatric cardiac catheterization laboratory with evidence of a discrete coarctation of the aorta. The hemodynamic data, angiograms and clinical records of 102 patients were examined, with follow-up data from 2 to 117 months (median 36.2) available in 92 patients. RESULTS: Immediate success with balloon angioplasty was achieved in 93 (91.2%) of the 102 patients. Seventy-one patients (77.2%) with intermediate follow-up data (range 12 to 117 months) available are asymptomatic and normotensive, with insignificant arm to leg blood pressure gradients (< or = 20 mm Hg). Twenty-one patients (22.8%) with an initial successful result developed an increase in gradient 2 at 86 months after angioplasty, requiring reintervention in 18. Follow-up > 72 months is available in 17 patients, 16 of whom are normotensive and have not required additional intervention. No additional intervention was needed in 88.4% of older children and infants > 7 months old. Ten of the 13 surviving neonates who initially had a successful dilation required reangioplasty or operation 14 days to 10 months (median 4.6 months) after angioplasty. Transverse arch hypoplasia had minimal effect on follow-up blood pressure gradient, whereas isthmic hypoplasia was associated with reintervention in 50%. A small aneurysm was noted in 2 (1.9%) of 102 patients. CONCLUSIONS: Balloon angioplasty of native aortic coarctation is effective in infants and older children. In neonates, balloon angioplasty provides effective palliation only. Aneurysm formation is rare; however, lifetime follow-up is warranted.

Adolescent↗
PubMed1994

Balloon angioplasty with stent implantation in experimental coarctation of the aorta.

BACKGROUND: Balloon angioplasty of coarctation of the aorta is an effective method of treatment but is complicated by tearing of the aortic intima, formation of aneurysms, and restenosis. Stent placement at the time of balloon dilation could prevent restenosis and could also prevent progression of intimal tears to aneurysms. The purpose of this study was to evaluate the feasibility of balloon dilation and implantation of balloon-expandable stents in an experimental model of coarctation and to examine the effect of stent placement at the site of surgically created stenosis. METHODS AND RESULTS: Coarctation of the aorta was surgically produced in 11 juvenile swine. Simultaneous coarctation angioplasty and stent implantation was performed in 10 animals 34 +/- 7.8 days after surgery. Repeat catheterization was performed 59 +/- 6 days after stent implantation. Five animals underwent reexpansion of stents with subsequent follow-up catheterization. Aortic specimens were examined by light microscopy and scanning electron microscopy. Coarctation angioplasty with stent implantation was successful in all, with an increase in coarctation diameter from 46 +/- 8.5% to 90 +/- 12.2% of proximal aortic diameter (P = .0001). Systolic pressure gradient decreased from 32 +/- 19.8 to 0.5 +/- 2.8 mm Hg (P < .001). All stents were patent at follow-up catheterization, with no evidence of intraluminal thrombosis. Reexpansion in five animals increased the stent diameter from a mean of 77.4 +/- 12.1% to 93 +/- 11.0% of proximal aortic diameter (P = .02). Gross examination of aortic specimens demonstrated formation of neointima over the stent wherever the stent struts were in contact with the aortic wall. The stent occupied a subintimal position and produced minimal compression of the underlying media. Medial compression was noted immediately beneath stent struts, but there was no evidence of intimal or medial dissection. CONCLUSIONS: Balloon angioplasty with simultaneous implantation of balloon-expandable stents is effective in relieving aortic obstruction in experimental coarctation. Reexpansion of the rigid stent can be performed in an area of surgical aortotomy and coarctation without significant intimal or medial injury. Stent implantation may be useful in preventing restenosis and aneurysm formation after angioplasty of coarctation.

Angioplasty, Balloon↗
PubMed1994

Successful closure of a previously unsuspected atrial septal defect by an implantable Clamshell device and subsequent transvenous pacemaker implantation.

Implantation of transvenous leads for a permanent cardiac pacing system usually requires the absence of intracardiac shunts. We report the case of an asymptomatic atrial septal defect in an 11-year-old boy who required permanent pacing. We implanted an atrial septal defect closure (Clamshell) device prior to implantation of transvenous leads. This new device makes transvenous implantation possible and may reduce the risk of stroke in patients with these anomalies.

Adolescent↗
PubMed1993

Transcatheter occlusion of patent ductus arteriosus in adults.

This study examines whether transcatheter closure of a patent ductus arteriosus (PDA) using a Rashkind PDA occluder device is safe and effective in adults, or if adults have complications not sited in children owing to prolonged aorticopulmonary communication, high surgical risks or calcified PDAs. Fifteen patients aged 22 to 76 years (mean 42 +/- 14) were referred for transcatheter PDA occlusion. Exercise intolerance was the most frequent clinical manifestation. Eleven of 15 patients had surgical risk factors that included left ventricular failure (n = 10), biventricular failure (n = 1), elevated pulmonary pressures (n = 1), and a calcified PDA (n = 5). Twelve millimeter devices were placed in 4 PDAs < or = 3 mm in diameter; 17 mm devices were placed in 11 PDAs 3 to 6 mm in diameter. Seven (47%) were occluded angiographically shortly after device placement; another 5 PDAs (33%) were occluded echocardiographically within 24 hours of the procedure. Completed occlusion in this time interval was more likely to occur in PDAs < 5 mm in diameter (p = 0.0009). Of the 3 remaining PDAs with follow-up ranging from 9 to 38 months, 2 have demonstrated gradual diminution of shunting and have trivial leaks by color/Doppler flow. The other patient with a residual PDA has no ductal flow after placement of a second device. No complications related to device implantation or closure of the PDA occurred in any patient. No complications were reported in the follow-up patients who received evaluation (14 of 15 patients; range 1 to 38 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Transcatheter closure of residual atrial septal defect following cardiac transplantation.

An almost 3-year-old boy had a residual atrial septal defect after cardiac transplantation. The patient was symptomatic and had arrhythmia and cardiac enlargement. An atrial septal defect occlusion device was employed to close the communication with excellent results. Transcatheter occlusion enabled the patient to avoid further surgery and did not interfere with follow-up endomyocardial biopsies.

Child, Preschool↗
PubMed1993

Balloon expandable intravascular stents: aortic implantation and late further dilation in growing minipigs.

Intravascular stents have been implanted in children with congenital and acquired vascular stenoses. Little information is known regarding the long-term results in growing patients, the implantation of multiple stents (in series), and the feasibility of further dilation. Nine stents were implanted in the abdominal aortas of 6 mini-pigs; in 3 pigs, 2 stents were implanted in series. Five pigs were recatheterized 196 +/- 17 days after stent implant. All stents were patent, with mild narrowing at the stent relative to the adjacent aorta; further stent dilation was performed. The stent diameter increased from 8.3 +/- 0.6 mm to 11.2 +/- 1.3 mm (p = 0.002), and the narrowing was relieved. These five pigs were catheterized 253 +/- 73 days after stent redilation. Each stent was patent without narrowing or pressure gradient. We conclude that intravascular stents do not interfere with normal growth, can be implanted in series, and can be further dilated.

Animals↗
PubMed1993

Re-expansion of balloon-expandable stents after growth.

OBJECTIVES: The purpose of this study was to evaluate the feasibility of re-expansion of balloon expandable intravascular stents and to examine the gross and histologic effects of re-expansion on vascular integrity. BACKGROUND: Intravascular stents have been used successfully as an adjunct to balloon dilation of congenital pulmonary artery branch stenosis and postoperative stenosis of the pulmonary arteries in children. However, use of rigid stents in children could result in development of relative stenosis at the site of stent implantation with subsequent growth of the child. METHODS: Stainless steel "iliac" stents were placed in the thoracic aorta of 10 normal juvenile swine by a transcatheter technique. Angiography and re-expansion were performed at a mean of 11 weeks (n = 9) and again at 18 weeks (n = 5). After euthanasia, the aortic specimens were removed for gross and histologic examination. RESULTS: Stents were successfully implanted in 10 swine. Re-expansion was successfully performed in each animal at 11 weeks and at 18 weeks. Aortic growth produced a relative constriction of the aorta of 20% +/- 10% (mean +/- SD) at the site of stent implantation at both 11 and 18 weeks. Re-expansion produced a significant increase in mean stent diameter from 10.1 +/- 1 mm to 12.3 +/- 1.2 mm at 11 weeks and from 11.2 +/- 0.7 to 13.5 +/- 1.1 mm at 18 weeks after implantation (p < 0.001). Balloon dilation produced a relative increase in stent diameter of 21% +/- 7% at 11 weeks and 18% +/- 4% at 18 weeks. Stent re-expansion was accompanied by plastic deformation of the neointima without neointimal dissection. Where neointima was thick, there was no evidence of neointimal abrasion, but where neointima was thin, areas of localized neointimal abrasion were observed with focal fibrin and platelet adherence to the stent struts. There was no evidence of medial or adventitial hemorrhage or dissection produced by re-expansion. CONCLUSIONS: Re-expansion of intravascular stents is feasible after growth in juvenile swine without significant injury to neointima, media or adventitia. The results of this study support careful and selective use of intravascular stents as an adjunct to balloon dilation of congenital stenoses in children.

Animals↗
PubMed1993

Implantation and intermediate-term follow-up of stents in congenital heart disease.

BACKGROUND: Balloon-expandable stents (Johnson and Johnson Interventional Systems) have been in use for congenital heart disease since late 1989. They have made possible treatment in previously untreatable branch pulmonary artery stenoses and systemic venous stenosis. The purpose of this report is to detail the results and intermediate-term follow-up of stents used for treatment of congenital heart disease. METHODS AND RESULTS: Eighty-five patients underwent placement of 121 stents in Houston and Boston. Fifty-eight patients had stents put in pulmonary arteries, nine had stents in conduits or outflow tracts, and 21 had stents in venous stenoses or narrowed Fontan anastomoses. (Three patients had stents in two locations.) These stent procedures resulted in gradient reduction from 55.2 +/- 33.3 to 14.2 +/- 13.5 mm Hg in pulmonary arteries, from 41.4 +/- 26.0 to 20.7 +/- 17.0 mm Hg in conduits or outflow tracts, and from 9.8 +/- 6.9 to 2.4 +/- 3.1 mm Hg in venous stenoses or Fontan anastomoses. Diameter of narrowings increased from 4.6 +/- 2.3 to 11.3 +/- 3.2 mm in the pulmonary artery, from 8.8 +/- 3.6 to 12.7 +/- 2.6 in conduits, and from 3.8 +/- 2.9 to 11.3 +/- 2.8 in venous stenoses. Follow-up has shown stent fracture in one patient, restenosis in one, and sudden death in one. Recatheterization has been done in 38 patients an average of 8.6 months after stent installation. Compared with immediately postimplant data, there was no significant change in luminal diameter or pressure gradient. Redilation was performed in 14 patients (17 stents) 1 week to 24 months after implantation (mean, 10.2 months), with a small but significant increase in stenosis diameter. CONCLUSIONS: We conclude that stent treatment of vascular stenoses in congenital heart disease retains efficacy at medium-term follow-up and offers a much-improved outlook for patients with these lesions.

Adolescent↗
PubMed1992

Double-transseptal, double-balloon valvuloplasty for congenital mitral stenosis.

BACKGROUND: Eight patients with severe congenital mitral stenosis underwent double transseptal, double-balloon valvuloplasty; two had isolated congenital mitral stenosis, six had additional cardiac defects, and one had previous surgical valvotomy. Ages ranged from 0.6 to 36 years (median, 9 years). METHODS AND RESULTS: All procedures were tolerated well. After valvuloplasty, the left atrial a wave minus the left ventricular end-diastolic pressure (LVEDP) gradient was reduced from 25 +/- 6 mm Hg to 9 +/- 3 mm Hg (p less than 0.001), the mitral valve mean gradient was reduced from 18 +/- 7 mm Hg to 8 +/- 3 mm Hg (p = 0.003), and the LVEDP was unchanged. All patients had marked clinical improvement. Only one patient developed significant mitral regurgitation. Two of the first four patients underwent repeat balloon valvuloplasty 7 months later. Follow-up evaluation on six patients from 4 to 54 months revealed no recurrence of symptoms or increased mitral regurgitation. CONCLUSIONS: Double transseptal, double-balloon valvuloplasty is an effective treatment for many forms of congenital mitral stenosis. Mitral regurgitation is uncommon after this procedure. The double transseptal approach results in less trauma to the atrial septum and femoral veins and allows easy assessment of any residual postvalvuloplasty gradient.

Adolescent↗
PubMed1992

Experience with 205 procedures of transcatheter closure of ductus arteriosus in 182 patients, with special reference to residual shunts and long-term follow-up.

Between December 1987 and September 1991, 205 nonsurgical procedures for closure of patent ductus arteriosus were attempted in 182 infants, children, and young adults with use of the Rashkind double-disc ductal occluding device. The patients' ages ranged from 8 months to 26 years (median 5 years) with 18 aged less than 2 years. Their weights ranged from 7.4 to 55 kg (median 16 kg); in patients aged less than 2 years the mean weight was 10.2 +/- 1.5 kg, and in those aged more than 2 years mean weight was 19.5 +/- 9.6 kg. Successful occluder device implantation was achieved in 174 patients (96%) at the initial attempt. Device embolization to a pulmonary artery occurred in six patients; two of these devices were retrieved by grabber catheter and four at operation, all without adverse sequelae; there were two other technical failures. Follow-up studies included two-dimensional Doppler echocardiography with color flow mapping. The 6-week follow-up study revealed a small residual shunt in 27% (46/169) of patients. At the 6-month follow-up study, 22% (37/167) of the patients had a small residual shunt; this prevalence was 17% (24/145) in ducts with a narrowest diameter of less than 6 mm, and 59% (13/22) in ducts greater than 6 mm. Immediately after implantation of the occluder device and throughout the follow-up period, the mean narrowest ductal diameter of ducts with residual shunts was significantly larger than that of ducts in which total occlusion was achieved (range of p < 0.01 to 0.001). The use of the 17 mm occluder device, however, was significantly associated with an increased prevalence of residual shunt only immediately after implantation (p < 0.01). Implantation of a second occluder device was attempted in 21 patients with residual patent ductus together with a continuous murmur at the 6-month follow-up; embolization of one device to a pulmonary artery occurred immediately but it was retrieved by grabber catheter and another device was successfully implanted 1 month later. All 21 patients were seen for 6-month follow-up study, when only one (5%) had a small residual shunt that was subsequently successfully closed by the insertion of a third occluder device. Thus, after successful implantation of one or more occluder devices, complete closure of the ductus was achieved in 90% of all patients seen to date for their 6-month follow-up study. One patient had limited hemolysis. The maximum follow-up period is 50 months. These results confirm the efficacy, with low morbidity and no mortality, of the use of the Rashkind occluder device for nonsurgical closure of patent ductus arteriosus, especially in those with smaller diameters.

Adolescent↗