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Biomedical subjects

J E Lock

Publications and source records attributed to J E Lock.

At least 55 records · Page 3Linked to original sources
PubMed1995

Balloon dilation of critical valvar pulmonary stenosis in the first month of life.

Between 1985 and 1992, 36 consecutive neonates, aged 1-29 days, weight 2.4-5.0 kg, with critical valvar pulmonary stenosis underwent attempted balloon dilation (BD). At catheterization, 30 were on prostaglandin (PGE1) therapy and 20 were intubated. The valve was successfully crossed and dilated in 34/36 (94%), including three with an echocardiographic diagnosis of valvar pulmonary atresia and a right ventricle of adequate size. The valve was first dilated with a 2- to 5-mm balloon and then with serially larger ones (up to 12 mm) to a final balloon/annulus value of 126%. The RV/systemic pressure value fell from 150 +/- 32 to 83 +/- 30%, O2 saturation rose from 91 +/- 6% to 96 +/- 4%, and PGE1 was discontinued at the end of the procedure. There were 11 complications (31%) including one early death from sepsis and necrotizing enterocolitis, endocarditis in another, two myocardial perforations, one femoral-iliac vein tear, and one transient pulse loss. A repeat BD was carried out in five patients, two of whom subsequently had surgery. At follow-up (33 +/- 23 months), the 31 patients managed by BD alone were well and had echocardiographic gradients of < 30 mm Hg in 90% and pulmonary regurgitation, considered mild in most, in 52%. In neonates with critical valvar pulmonary stenosis, we believe BD mortality is less than with surgery and is the treatment of choice.

Catheterization↗
PubMed1995

Echocardiographic predictors of candidacy for successful transcatheter atrial septal defect closure.

We reviewed pre-closure echocardiograms on all patients undergoing transcatheter atrial septal defect (ASD) closure with the Bard double-umbrella occluder device aided by simultaneous transesophageal echocardiography to determine precatheterization predictors of outcome. Transesophageal echocardiograms were performed on 28 of 132 patients (22%) undergoing device closure (age = 3-72 years, mean = 14 years; weight = 15-68 kg, mean = 35 kg). Three devices were removed because of unstable position. Of the remaining 25 patients, 21 had effective closure (residual flow diameter < or = 3 mm) and 18 had favorable arm position (device arm on proper side of the septum and not in contact with an atrioventricular valve leaflet). Only ASD size predicted effective closure. All patients with a maximum defect size of < 13 mm had effective closure. Among the 17 patients with defects > or = 13 mm, 10 had effective closure, 4 had significant residual flow, and 3 had devices removed for unstable position. Atrial dimensions and rim size did not predict effective closure. There were no pre-closure predictors of favorable arm position which was associated only with the size of the device implanted.

Adolescent↗
PubMed1995

Orthodeoxia-platypnea due to intracardiac shunting--relief with transcatheter double umbrella closure.

The safety and efficacy of transcatheter clamshell occlusion of patent foramen ovale for relief of severe arterial desaturation and dyspnea in the upright position due to intracardiac shunting were examined in eight patients with excessive risk of surgical patent foramen ovale closure. All patients had successful reduction of intracardiac shunting with an immediate rise in oxygen saturation > or = 95% by implantation of a clamshell device on the atrial septum. Despite two early incidents of device embolization, retrieval and immediate re-implantation, and one patient with nonsustained atrial and ventricular arrhythmias, there were no adverse clinical sequelae. In follow-up evaluation transcatheter clamshell closure of patent foramen ovale has provided persistent relief from shunt-related arterial desaturation and symptomatology in all living patients.

Adult↗
PubMed1995

Intraaortic spring coil loops: early and late results.

OBJECTIVES: Our aim was to determine the late fate of intraaortic spring coil loops after embolization of aortopulmonary vessels. BACKGROUND: In some aortopulmonary collateral vessels and patent ductus arteriosi, the narrowest segment is close to the aorta; coils used to close such vessels will "straddle" the lesion, allowing one or more coil loops to protrude into the aortic lumen. The consequences of this procedure are unknown. METHODS: We reviewed the cineangiograms of all patients who had at least one aortopulmonary collateral vessel or patent ductus arteriosus closure between January 1, 1988 and August 31, 1993. From this group, 53 patients had multiple-plane angiographic evidence of intraaortic coil loops. All subsequent cineangiograms were reviewed to determine coil position or movement and evidence of recanalization or endothelial coverage of the coil loop. We also reviewed each hospital record or communicated directly with referring physicians to identify any subsequent complications such as emboli or endocarditis. RESULTS: Of the 53 patients with intraaortic coil loops, 49 patients had closure of one or more aortopulmonary collateral vessels (59 vessels), and 4 had closure of a patient ductus arteriosus (4 vessels). Patient follow-up ranged from 1 day to 66 months (median 20 months); follow-up was not available in 6 patients. Five of the 53 patients (9.3%; 95% confidence limits [CL] 3.1% to 20.7%) died at operation or of end-stage heart failure. Patients with late angiography had no residual flow in 31 of 35 aortopulmonary collateral vessels (88.6%; 95% CL 73.3% to 96.8%), and 0.5 mm separated the coil and aortic contrast column in all 12 coils with adequate angiography, suggesting endothelial coverage of the intraaortic coil loop. No episodes of stroke, embolic events, endocarditis or coil migration were reported. CONCLUSIONS: Although coil occlusion of aortopulmonary collateral vessels or patent ductus arteriosi may produce intraaortic coil loops, endothelialization appears routine. No late complications associated with intraaortic coil loops were observed.

Aorta, Thoracic↗
PubMed1995

Cardiac catheterization and test occlusion of the interatrial communication after the fenestrated Fontan operation.

OBJECTIVES: Our objective was to determine whether catheterization data obtained after a fenestrated Fontan operation influenced patient management or predicted functional status. BACKGROUND: Cardiac catheterization after a fenestrated Fontan operation is undertaken to identify residual lesions and to observe the patient's response to test occlusion of the baffle fenestration. METHODS: Sixty patients undergoing both a fenestrated Fontan operation before July 1991 and a postoperative catheterization before March 1992 were included in the study. Catheterization data were collected according to a test occlusion protocol; these data were reviewed, and the patient's clinical status at follow-up was ascertained. RESULTS: Test occlusion resulted in a significant increase in systemic venous pressure, arterial oxygen saturation and arteriovenous difference in oxygen content (p < 0.0001). After test occlusion, systemic venous pressure was 40% higher and systemic venous saturation 23% lower among patients with an unfavorable versus a favorable response to test occlusion, although differences between the two groups were subtle or inapparent in the baseline state. Branch pulmonary artery stenosis (identified and balloon dilated in 6 patients) and grade 2 or 3 aortopulmonary collateral vessels (identified and coil embolized in 20) were associated with elevation in systemic venous pressure (p < 0.01). After an average of 2 years of follow-up, there were no deaths, and 50 (83%) of 60 patients were in New York Heart Association functional class I. The only postoperative characteristic significantly associated with being in functional class I at follow-up was a systemic venous pressure < 17 mm Hg. CONCLUSIONS: Cardiac catheterization with test occlusion of the interatrial communication provides useful information after a fenestrated Fontan operation. Conditions associated with elevated systemic venous pressure should be sought and treated, and the response of systemic venous pressure to test occlusion should be considered when deciding whether to close an interatrial communication.

Cardiac Catheterization↗
PubMed1995

Cerebrovascular accidents following the Fontan operation.

The Fontan operation is one of the most common cardiac operations for children with congenital heart disease beyond the first year of age. Although the surgical mortality of this procedure has improved over the past 2 decades, the neurologic outcome in this population is not well described. We performed a retrospective review of 645 patients who underwent the Fontan procedure at Children's Hospital in Boston over the 15-year period between August, 1978 and July, 1993, to describe the incidence of postoperative cerebrovascular accidents or strokes among survivors. We identified 17 patients (2.6%) who suffered a stroke following the Fontan operation. The risk period for stroke in our population extended from the first postoperative day to 32 months after the Fontan procedure. The pre-, intra-, and postoperative clinical features of these patients are described.

Adolescent↗
PubMed1995

Transcatheter closure of ventricular septal defects: hemodynamic instability and anesthetic management.

The technique of transcatheter ventricular septal defect (VSD) device closure may be associated with significant hemodynamic instability. The anesthetic records and catheterization data of 70 consecutive transcatheter VSD closures between February 1989 and September 1992 were reviewed, and risk factors associated with hemodynamic instability evaluated. In 28 of 70 procedures (40%), hypotension (> 20% decrease in systolic blood pressure from baseline) occurred; 12 responded to administration of fluids intravascularly alone, whereas 16 patients required additional acute resuscitation. Significant dysrhythmias occurred during 20 (28.5%) anesthetics associated with hypotension and requiring treatment or catheter withdrawal. ASA physical status, precatheterization indication for device placement, and patient size were not predictive of hemodynamic instability during the procedure. Blood transfusions were necessary in 38 (54.4%) cases and were size-related, with patients weighing less than 10 kg requiring a significantly larger transfusion volume (25.1 +/- 12.4 mL/kg). After 35 procedures (50%) patients were admitted directly to the intensive care unit (ICU) due primarily to hemodynamic instability or procedure duration; 24 (68%) required mechanical ventilation. No deaths occurred; there was no late morbidity due to catheterization-related events. Intravenous sedation was used for the initial catheterizations, maintained with a combination of midazolam, ketamine, and morphine. Subsequently general intravenous or inhaled anesthesia was predominantly used during transesophageal echocardiography and internal jugular vein cannulation. We conclude that hemodynamic instability is common during device closure of VSDs, and is likely to be an inescapable feature of these procedures in many patients because of the technique necessary for device placement.

Anesthesia↗
PubMed1995

In-hospital mortality for surgical repair of congenital heart defects: preliminary observations of variation by hospital caseload.

OBJECTIVE: To examine the impact of hospital caseload on in-hospital mortality for pediatric congenital heart surgery. DESIGN: Population-based, retrospective cohort study. SETTING: Acute care hospitals in California and Massachusetts. PATIENTS: Children undergoing surgery for congenital heart disease, identified by the presence of procedure codes indicating surgical repair of a congenital heart defect in computerized statewide hospital discharge abstract databases. Cases were grouped into four categories based on the complexity of the procedure. MAIN OUTCOME MEASURES: Adjusted odds ratios (OR) for in-hospital death were estimated using generalized estimating equations that account for the intra-institutional correlation among patients. RESULTS: A total of 2833 cases at 37 centers were identified. Compared with centers performing > 300 cases per year, after controlling for patient characteristics, centers performing < 10 cases per year had an OR for in-hospital death of 7.7 (95% confidence interval (CI) [1.6-37.8]); 10 to 100 cases, OR = 2.9 (95% CI [1.6-5.3]); 101 to 300 cases, OR = 3.0 (95% CI [1.8-4.9]). Independent risk factors for mortality included procedure complexity category (P < .0001), use of cardiopulmonary bypass (P < .0001), young age at surgery (P = .001), and transfer from another acute care hospital (P < .0001). Few differences were found by hospital caseload in length of stay or total hospital charges. CONCLUSIONS: For children with a congenital heart defect who underwent surgery in California in 1988 or Massachusetts in 1989, the risk of dying in-hospital was much lower if the surgery was performed at an institution performing > 300 cases annually. This study was limited by the absence of clinical detail in discharge abstract databases. If these findings are corroborated by other studies, health care delivery strategies that direct children requiring surgical correction of congenital heart defects to high-volume centers may substantially reduce overall mortality.

California↗
PubMed1994

Balloon aortic valvuloplasty in the young adult with congenital aortic stenosis.

Although balloon aortic valvuloplasty (BAV) is effective in the acute management of valvar aortic stenosis (AS), sustained benefit of this technique has been shown to vary in differing age groups. The role of BAV in the young adult with congenital, nondegenerative AS is poorly defined. The catheterization results and follow-up echocardiographic data were reviewed for all patients (n = 18) between the ages of 17 and 40 years (mean 23 +/- 7) undergoing BAV at our institution between March 1986 and January 1992. Peak-to-peak systolic ejection gradient was reduced by 55%, from 85 +/- 29 to 38 +/- 17 mm Hg (p < 0.001). Aortic valve area increased from 0.9 +/- 0.2 to 1.1 +/- 0.3 cm2 (p = 0.003). Results of dilation were inadequate in 2 patients. There were no deaths, myocardial infarction, or embolic events. The 16 "effectively" dilated patients were followed with serial echocardiography for a period of 1 to 82 months, demonstrating persistent gradient relief in most patients (maximal instantaneous gradient at follow-up, 55 +/- 17 vs 79 +/- 22 mm Hg before dilation, p < 0.001). Aortic valve replacements were performed in 5 patients, 2 with unsuccessful initial dilations. At the time of the most recent echocardiogram, 8 of 16 patients remained "incident free," with no subsequent catheterization or surgical interventions, a maximal instantaneous gradient of < or = 55 mm Hg, no more than moderate aortic regurgitation, and preserved ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Traumatic aortopulmonary window as a complication of pulmonary artery balloon angioplasty: transcatheter occlusion with a covered stent. A case report.

We describe a case in which pulmonary artery balloon angioplasty was complicated by formation of an aortopulmonary window, a previously unreported complication associated with this technique. A novel transcatheter approach for occluding the defect, a covered stent, was utilized. Deployment of the covered stent significantly reduced the shunt, allowed for clinical stabilization, and averted the need for emergency surgical intervention.

Angioplasty, Balloon↗
PubMed1994

Transesophageal echocardiographic guidance of transcatheter ventricular septal defect closure.

OBJECTIVES: This report describes transesophageal echocardiographic guidance of transcatheter closure of ventricular septal defects and its value as an adjunct to fluoroscopy and angiography in this procedure. BACKGROUND: Experience with transcatheter closure of ventricular septal defects has identified a diverse group of patients in whom it may be the procedure of choice. Although facilitating other interventional procedures, such as transcatheter closure of atrial septal defects, the value of transesophageal echocardiographic guidance for transcatheter ventricular septal defect closure has not been documented. METHODS: All patients who underwent ventricular septal defect closure with transesophageal echocardiographic guidance before November 1992 were included. Angiograms and echocardiograms were reviewed to evaluate device position and relation to valve tissue during placement and to assess residual flow after device implantation. The ability of transesophageal echocardiography to assess these variables was compared with fluoroscopy and angiography. RESULTS: Transesophageal echocardiographic guidance was used in 31 of the 83 catheterizations involving transcatheter ventricular septal defect closure performed between February 1990 and November 1992. Under transesophageal echocardiographic guidance, 45 devices were implanted: 23 in muscular ventricular septal defects, 17 in residual postoperative patch margin defects and 5 in other ventricular septal defects. Transesophageal echocardiographic guidance enhanced assessment of device position and proximity to valve structures and markedly improved assessment of residual flow. Assessment of residual flow with transesophageal echocardiography eliminated the need for multiple angiograms in some patients. Combining transesophageal echocardiography with fluoroscopy and angiography provided the most information. CONCLUSIONS: Transesophageal echocardiography facilitates transcatheter closure of ventricular septal defects by improving assessment of device position and effectiveness of closure. It is indicated when device placement is likely to be difficult or may interfere with valve structures or when multiple interventional procedures are anticipated.

Adolescent↗
PubMed1994

Management and outcome of low birth weight neonates with congenital heart disease.

In 100 consecutive neonates with birth weights < or = 2500 gm (range, 540 to 2500 gm; median, 2200 gm), major congenital heart disease (excluding patent ductus arteriosus, isolated atrial septal defect, and ventricular septal defect) was diagnosed between January 1987 and January 1991; 46 had ductus-dependent lesions. Of the 100 neonates, 30 had genetic aberrations or significant associated congenital anomalies. The four most common cardiac diagnoses were tetralogy of Fallot with or without pulmonary atresia (n = 16); coarctation of the aorta (n = 12); transposition of the great arteries (n = 11); and common atrioventricular canal (n = 11). The hospital survival rate for the entire group of 100 neonates was 70%. The patients were separated into three groups on the basis of the time of intervention. Group 1 (early intervention) included 62 infants. These neonates (including 31 with ductus-dependent lesions) had surgical or catheter intervention during the initial hospitalization (median age, 9 days), all at weights < or = 2500 gm. The hospital survival rate was 81% (50/62); survival rates for palliation (78%, 18/23) and for correction (82%, 32/39) were similar. There were 26 neonates in group 2 (late intervention). These neonates did not have surgical intervention during the initial hospitalization. All were managed medically; survivors were discharged and had surgical procedures later (at a median age of 4.3 months). Six neonates (23%) died during medical management; all 20 survivors returned and had surgical procedures, with 90% survival. Overall survival rate for this group was 69% (18/26). The remaining 12 patients (group 3) had complicating features that precluded intervention; none survived. On the basis of these results, we conclude that early intervention, even with corrective surgery, can be performed in low birth weight neonates with an acceptable mortality rate. Prolonged medical therapy to achieve further weight gain did not appear to improve the survival rate.

Cardiac Catheterization↗
PubMed1994

Leaf-level and whole-plant gas exchange characteristics of shortleaf pine exposed to ozone and simulated acid rain.

Field-grown shortleaf pine (Pinus echinata Mill.) seedlings were exposed to ozone (O(3)) and simulated acid rain (SAR) in open-top chambers over three growing seasons. Ranges of O(3) and SAR spanned ambient levels found in the southern USA. Effects of O(3) on leaf-level and whole-plant gas exchange were characterized for a single measurement period immediately before the third summer of exposure. Decreased photosynthesis rates were attributed to O(3), but not SAR. Stomatal conductance decreased in response to O(3) exposure, and either increased or was unaffected by SAR. Increased internal CO(2) concentration (c(i)) in response to O(3) treatment indicated a greater effect of O(3) on photosynthetic capacity than stomatal conductance. Whole-seedling gas exchange characteristics indicated that whole-seedling carbon assimilation was more severely affected by O(3) than was evident from leaf-level gas exchange characteristics. Seedlings exposed to O(3) retained fewer flushes than seedlings grown in charcoal-filtered air.

Journal Article↗
PubMed1994

"Intramural" residual interventricular defects after repair of conotruncal malformations.

BACKGROUND: We report an unusual type of residual interventricular communication in patients with conotruncal malformations in which the aorta is completely or partly aligned with the right ventricle (RV). Interventricular communications after surgical repair usually result from additional defects, patch dehiscence, or incomplete closure and lie in the septal plane. However, after a right ventricular aorta is baffled to the left ventricle, the ventricular septal defect (VSD) patch and RV free wall form part of the systemic outflow tract. This "neo-left ventricular" outflow tract may provide a location for residual interventricular communications out of the septal plane. METHODS AND RESULTS: We reviewed echocardiographic, angiographic, and clinical records of patients who had one or more residual interventricular communications out of the plane of the ventricular septum after repair of a conotruncal anomaly. Between June 1990 and October 1992, we observed such defects in eight patients, 5 to 26 years old, after repair of double-outlet right ventricle (n = 6), tetralogy of Fallot (n = 1), or truncus arteriosus (n = 1). In each, the VSD patch was anchored to the RV free wall near the aortic root. Nonetheless, channels were observed around the edge of the patch, between the neo-systemic outflow tract and the right ventricle. All patients had right ventricular hypertension; in seven, the pulmonary-to-systemic flow ratio (Qp:Qs) was > or = 2. At multiple unsuccessful reoperations (two to four per patient), the patch edges appeared securely attached to myocardium. Angiographic views profiling the septum failed to localize these defects, since they are not in the native septum. Echocardiographic detection of such anterior defects can be difficult. Transcatheter umbrella closure was attempted in the seven patients with large shunts; success was limited by the multiplicity of flow channels. Umbrella closure eliminated the need for further reoperation in four of seven patients, one patient died suddenly awaiting reoperation, and two deaths followed reoperation. CONCLUSIONS: "Intramural" residual interventricular defects are difficult to diagnose by all modalities. Umbrella placement may reduce the left-to-right shunt. Successful surgical closure may require removal and reattachment of the anterior portion of the patch.

Angiocardiography↗
PubMed1994

Severe congenital mitral stenosis in infants.

BACKGROUND: Despite current medical and surgical therapy, infants with symptomatic congenital mitral stenosis (CMS) continue to have high rates of morbidity and mortality. Catheter balloon dilation has been successful in relieving symptoms in a few older children with CMS but has not been evaluated in infants. METHODS AND RESULTS: We reviewed the records of 85 infants with CMS to assess severity of CMS, associated cardiac lesions, echocardiographic morphological appearance of the mitral valve, treatment, and outcome. There were five valve morphologies identified: "typical" hypoplastic mitral valve with symmetric papillary muscles (SYMM, 52%), supravalvar mitral ring (SVMR, 20%), double-orifice mitral valve (DOMV, 11%), hypoplastic mitral valve with asymmetric papillary muscles (ASYMM, 8%), and parachute mitral valve (PARA, 8%). Of the 85 infants, 31 (36%) were severely symptomatic, requiring intervention within the first 2 years. Balloon dilation was performed in 18 infants (age, 8.7 +/- 5.7 months; weight, 5.9 +/- 1.9 kg) and valve surgery in 13 (age, 10.9 +/- 5.9 months; weight, 6.7 +/- 2.1 kg). Balloon dilation decreased the peak transmitral gradient (LAa-LVED) > 30% in 15 of 18 initial attempts, from 20.3 +/- 8.2 to 10.9 +/- 4.9 mm Hg (P < .001), and the mitral valve area increased from 0.7 +/- 0.3 to 1.0 +/- 0.5 cm2/M2 (n = 10, P = .01). No infants died during the initial balloon dilation, although 2 of 3 died during a repeat procedure for restenosis. Other complications included significant mitral regurgitation in 7 of 18 patients (39%), 4 of whom had SVMR. Of the 18 infants, 8 (44%) had persistent symptomatic improvement at a mean follow-up of 14 months (range, 2 to 32 months). The 2-year survival after balloon dilation was 70%; 40% remained free of repeat intervention. Mitral valve surgery in 13 infants consisted of SVMR resections in 7, mitral valve replacements in 4, and LA-to-LV aortic valved homografts in 2. The operative mortality was 30%. Sustained improvement occurred in 8 (6 with SVMR) at 11 to 62 months of follow-up (mean, 30 months), with a 2-year survival of 60%. CONCLUSIONS: Infants with severe CMS have 2-year mortality rates approaching 40% regardless of treatment modality. Balloon dilation significantly reduces the transmitral gradient in the majority, but symptomatic improvement persists in only 40%. Procedure-related mortality was associated with repeat balloon dilation in patients with left ventricular hypoplasia. Balloon dilation of "typical" CMS can provide symptomatic relief in many infants, allowing postponement of valve replacement, although infants with SVMR do better with surgical management.

Cardiac Catheterization↗
PubMed1993

Catheter ablation of accessory atrioventricular pathways in young patients: use of long vascular sheaths, the transseptal approach and a retrograde left posterior parallel approach.

OBJECTIVES: This study retrospectively assesses the technical aspects of the catheter techniques used to ablate 83 accessory atrioventricular (AV) pathways during 88 procedures in 71 pediatric and adult patients (median age 14 years, range 1 month to 55 years). A number of catheter approaches and techniques evolved that may have improved success and shortened procedure times. BACKGROUND: Radiofrequency catheter ablation of accessory AV pathways can be highly successful. However, the technical difficulty of many of the procedures is masked by the success rate. METHODS: Left free wall, right free wall and septal accessory pathways were ablated with a variety of approaches. RESULTS: Left free wall pathways were ablated successfully by using a standard retrograde approach through the aortic valve in only 10 (24%) of 43 cases. The remaining 33 (76%) required an approach that was either retrograde through the mitral valve (2 of 33), transseptal (21 of 33) or retrograde where the catheter was advanced behind the posterior mitral leaflet at the point of mitral-aortic continuity, so that the catheter course was parallel rather than perpendicular to the mitral anulus (10 of 33). Nineteen of 20 septal pathways were ablated successfully by using either the parallel approach (2 of 29), a transseptal approach (2 of 19), ablation within the coronary sinus or one of its veins (8 of 19) or ablation on the atrial side of the tricuspid valve (7 of 19). Fifteen of 20 right free wall pathways were ablated successfully with a variety of approaches on both the atrial and the ventricular side of the tricuspid valve. Long vascular sheaths were judged to contribute directly to success in 33 (43%) of 77 pathways. The overall success rate has been 93% (77 of 83 pathways), with 100% success for left free wall (43 of 43), 75% for right free wall (15 of 20) and 95% for septal pathways (19 of 20). CONCLUSIONS: Thus, successful ablation of accessory AV pathways in a mixed group of pediatric and adult patients appears to benefit from a wide range of vascular and catheter approaches.

Adolescent↗
PubMed1993

High pressure balloon angioplasty for branch pulmonary artery stenosis: early experience.

OBJECTIVES: The aim of this study was to evaluate the efficacy and safety of high pressure balloons (17 to 20 atm, Blue Max, Meditech) to dilate branch pulmonary artery stenosis. BACKGROUND: The low success rate (50% to 60%) for angioplasty of branch pulmonary artery stenosis using low pressure balloons is due primarily to the inability to eliminate the balloon waist. Hence, higher inflation pressures may improve results. METHODS: Hemodynamic and angiographic data from 52 patients (0.3 to 34.8 years old) who underwent high pressure balloon dilation of branch pulmonary artery stenosis between October 1990 and February 1992 were reviewed retrospectively, as were data from previous low pressure dilations in these patients. Common diagnoses included tetralogy of Fallot (n = 9), tetralogy of Fallot with pulmonary atresia (n = 23), single ventricle (n = 8) and isolated congenital pulmonary stenosis (n = 7). The 52 patients had 72 vessels dilated. Criteria for success were a > or = 50% increase in vessel diameter or a > 20% decrease in right ventricular to aortic pressure ratio. RESULTS: Of 36 vessels with previously unsuccessful low pressure balloon dilation, 23 (63%) were successfully dilated with high pressure balloons. Of the 36 remaining vessels, 29 (81%) were successfully dilated with high pressure balloons. Factors associated with success were stenosis at a surgical anastomosis and disappearance of the balloon waist with dilation. Aneurysms developed in three vessels. Complications occurred in seven patients (13%); in two patients the distal pulmonary artery was perforated by a stiff guide wire, causing death in one. CONCLUSIONS: Dilation of stenotic peripheral pulmonary arteries with high pressure balloons improves the success rate of angioplasty both in patients who have had unsuccessful dilation with a low pressure balloon and in those without previous attempted dilation.

Adolescent↗