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Biomedical subjects

J E Lock

Publications and source records attributed to J E Lock.

At least 91 records · Page 5Linked to original sources
PubMed1992

Effect of baffle fenestration on outcome of the modified Fontan operation.

BACKGROUND: The "fenestrated Fontan" (surgical baffle fenestration followed by transcatheter test occlusion and permanent closure after postoperative recovery) was adopted in an effort to reduce perioperative mortality and morbidity. This study assesses the effect of baffle fenestration on outcome. METHODS AND RESULTS: Patients having a modified Fontan operation with a cavocaval baffle and cavopulmonary anastomosis were retrospectively selected for study. Those with baffle fenestration (n = 91) were compared with those without baffle fenestration (n = 56) with respect to preoperative risk factors, age, anatomy, surgical date, and presence or absence of a previous bidirectional cavopulmonary anastomosis. Outcome variables were failure (death or take-down) and duration of postoperative pleural effusions and hospitalization. Survival and clinical status after hospital discharge were ascertained. The two groups did not appear to differ with respect to age or anatomic diagnosis. Patients having baffle fenestration were at significantly greater preoperative risk by univariate and multivariate analysis (p < 0.01). Operative failure was low in both groups (11% without and 7% with baffle fenestration, p = NS). Durations of pleural effusions and hospitalization were significantly shorter with baffle fenestration (p < 0.01). Neither date of surgery nor a previous bidirectional cavopulmonary anastomosis appeared to contribute to improved outcome. Patients with baffle fenestration had lower postoperative systemic venous pressure (p < 0.01). There were no late deaths. Functional status in both groups is good (82% in New York Heart Association class I). CONCLUSIONS: Baffle fenestration is associated with low mortality, significantly less pleural effusion, and significantly shorter hospitalization among high-risk patients having a modified Fontan operation.

Cardiac Surgical Procedures↗
PubMed1992

Transcatheter closure of patent foramen ovale after presumed paradoxical embolism.

BACKGROUND: Many have proposed a relation between presence of a patent foramen ovale, with or without atrial septal aneurysm, and cryptogenic stroke. The effect of foramen ovale closure on the risk for subsequent strokes is unknown. METHODS AND RESULTS: Transcatheter closure of a patent foramen ovale was undertaken in 36 patients with known right-to-left atrial shunting and presumed paradoxical emboli (31 strokes, 25 transient neurological events, four systemic arterial emboli, and two brain abscesses). Individual patients had between one and four such events. None had a left heart or carotid source of embolism; 31 of 35 had no known risk factors for stroke. Events occurred in 12 patients while they were taking warfarin. At cardiac catheterization, patent foramina ovalia were significantly larger than predicted for age in 67% of the patients. Implantation of a double-umbrella device in the patent foramen ovale was achieved in all without serious procedural complications. Of 34 who have returned for follow-up, one has a residual atrial communication that may be clinically important, five had trivial leaks, and 28 have complete closure. There have been no strokes during a mean follow-up of 8.4 months. CONCLUSIONS: Transcatheter closure of a patent foramen ovale can be accomplished with little morbidity and may reduce the risk of recurrence. Further investigations directed toward identifying the population at risk and assessing the effect of intervention are warranted.

Actuarial Analysis↗
PubMed1992

Factors associated with choreoathetosis after cardiopulmonary bypass in children with congenital heart disease.

BACKGROUND: Choreoathetosis (CHO) after congenital heart surgery has been described since 1960. Risk factors and patient outcome have not been well defined. METHODS AND RESULTS: As our complexity of cases increased and management of pH on cardiopulmonary bypass (CPB) evolved, we noted the appearance of CHO among patients beginning in 1986. We reviewed the hospital course and follow-up of all 19 affected children, including eight younger patients (median age, 4.3 months) who developed a mild transient form of CHO, all of whom survived and had complete resolution of CHO; seven of these eight patients had deep hypothermic circulatory arrest (DHCA). Eleven older patients (median age, 16.8 months) developed severe persistent CHO; 11 had DHCA, 10 were cyanotic, seven had anatomic pulmonary atresia, and three others were physiologically analogous with a systemic to pulmonary artery shunt-dependent circulation. Five of six patients who had pertinent preoperative angiography had systemic to pulmonary collateral vessels arising from the head and neck arteries. Mortality in severe patients was 36% (four of 11); the seven survivors showed improvement, but only one had a normal neurological examination after 60 months of follow-up. When severe CHO patients were compared with 17 age- and diagnosis-matched patients without neurological complications, no differences were found in CPB or DHCA times, arterial blood gases, or hematocrits. Time from onset of CPB to onset of DHCA (time to shutoff) was shorter in the severe persistent CHO group than for comparison patients (22 +/- 7 versus 40 +/- 29 minutes, p = 0.053). CONCLUSIONS: Factors that may be associated with the development of severe persistent CHO include 1) age beyond early infancy, 2) cyanotic heart disease with systemic to pulmonary collaterals, particularly those arising from the head and neck vessels, and 3) the duration of the cooling period used in conjunction with deep hypothermic circulatory arrest. We advocate earlier reparative surgery, precise preoperative diagnosis and preoperative or intraoperative control of systemic to pulmonary artery collaterals, and further study of pH effects during CPB on development of CHO.

Athetosis↗
PubMed1992

Factors associated with marked reduction in mortality for Fontan operations in patients with single ventricle.

The Fontan operation was originally employed for patients with tricuspid atresia, but its application has been extended to those with a variety of complex defects in which there is functionally only a single ventricular chamber. The outcome of 225 modified Fontan operations carried out between 1984 and 1990 at the Children's Hospital, Boston, for patients with defects other than tricuspid atresia was reviewed. Overall 30 patients (13.3%) had failure of this operation (death or takedown). Results improved significantly during the period of the study, with failure rates of 6.5% (2 of 31) and 3.4% (2 of 59) in the last 2 years of the review. Multivariate analysis showed that pulmonary artery distortion, pulmonary artery pressure, age less than 3 years, use of a nonoxygenated glucose K+ cardioplegic solution, and cardiopulmonary bypass time greater than 180 minutes were associated with worse outcome, while "favorable" atrioventricular valve anatomy (non-left atrioventricular valve stenosis/atresia or common atrioventricular valve) and age greater than 9 years were associated with improved outcome. Excluding cardiopulmonary bypass time from the multivariate analysis, the technique of atrial partitioning for patients with left atrioventricular valve atresia/stenosis became the most important variable, followed by the others noted in the initial multivariate analysis except for age greater than 9 years. In the last 2 years of the study 31.1% of patients were less than 3 years of age. During the period of the study there was no significant decline in preoperative risk factors. These results show that modified Fontan operations can be carried out with a high likelihood of success in properly selected patients with complex defects in whom there is functionally a single ventricle.

Age Factors↗
PubMed1991

Transcatheter closure of a large patent ductus arteriosus with the clamshell septal umbrella.

In 14 patients undergoing transcatheter closure of a large (greater than 4 mm diameter) patent ductus arteriosus, occlusion was attempted with use of the Bard Clamshell septal umbrella. Patient age ranged from 0.7 to 30.4 years. Isolated patent ductus arteriosus was present in 11 patients; 3 had additional congenital heart lesions. Moderate or severe pulmonary hypertension was present in four patients. The diameter of the patent ductus arteriosus ranged from 4.5 to 14 mm, as determined by contrast injection through an 11F sheath or by balloon sizing; it appeared larger by this method than by the standard angiographic method. All 14 patent ductus arteriosi were successfully closed. Prior embolization of a Rashkind umbrella was the reason for using a Clamshell device in three patients; one additional embolization of a Clamshell device occurred. All errant devices were retrieved at cardiac catheterization, without associated hemodynamic instability. No other complications occurred. Among the 14 patients, 11 had complete ductal closure by Doppler color flow mapping at last follow-up and 3 had trivial residual flow. All four patients having associated complex lesions or pulmonary hypertension, or both, had symptomatic improvement after the procedure, although one child (with Shone's anomaly) died 3 months later. The Clamshell device provides stable and effective closure of a large patent ductus arteriosus, and allows transcatheter closure to be offered to some patients who were previously considered unsuitable for this procedure.

Adolescent↗
PubMed1991

Preoperative transcatheter closure of congenital muscular ventricular septal defects.

BACKGROUND: Surgical repair of muscular ventricular septal defects, particularly those associated with complex heart lesions carries a higher risk of reoperation and death than the repair of membranous defects. Closing a muscular defect through an incision in the systemic ventricle may cause late ventricular dysfunction. In a collaborative approach to this problem, we undertook preoperative transcatheter closure of muscular ventricular septal defects remote from the atrioventricular and semilunar valves, followed by the surgical repair of associated conditions. METHODS: In 12 patients selected jointly by a cardiologist and a cardiac surgeon, we attempted preoperative transcatheter umbrella closure of 21 defects. Half the patients had associated complex heart lesions; the others had had pulmonary-artery banding to reduce the amount of left-to-right shunting. Half had severe ventricular septal deficiency. RESULTS: All 21 defects were successfully closed without major complications. Subsequent cardiac surgery for associated conditions in 11 of the 12 patients resulted in a mean pulmonary-to-systemic flow ratio of 1.1, indicating minimal residual left-to-right shunting; 1 patient awaited surgical repair. No deaths, reoperations, or late complications have occurred after a follow-up of 7 to 20 months. CONCLUSIONS: A collaborative approach using transcatheter closure followed by the surgical repair of associated cardiac lesions may decrease rates of operative mortality, reoperation, and left ventricular dysfunction in patients with muscular ventricular septal defects.

Adult↗
PubMed1991

Two-dimensional echocardiography in the pre- and postoperative management of totally anomalous pulmonary venous connection.

The records of 23 infants who underwent surgical repair of isolated totally anomalous pulmonary venous connection were reviewed to assess the accuracy of pre- and postoperative echocardiographic diagnoses. Preoperative echocardiographic diagnoses were accurate in 22 of 23 patients, including the sites of connection of the individual pulmonary veins. Cardiac catheterization in 13 patients confirmed the echocardiographic findings. Analysis of multiple pre- and postoperative variables revealed no statistically significant difference between the infants with and without catheterization, although there was a tendency toward a higher mortality rate in the catheterized group. Postoperative echocardiographic examination revealed obstruction to pulmonary venous return in 7 of 19 patients. Catheterization confirmed the echocardiographic findings, localizing the obstruction in one patient. The size of the venoatrial anastomosis was measured on postoperative echocardiograms performed on 14 patients. The cross-sectional area of the anastomosis was less than 0.3 cm2/m2 of body surface area in the four patients with obstruction of the anastomosis, and greater than 0.95 cm2/m2 in all long-term survivors examined. Two-dimensional echocardiography with pulsed Doppler examination and Doppler color flow mapping is an excellent means of diagnosing totally anomalous pulmonary venous connection. The connections of the individual pulmonary veins can be identified in nearly all cases. Surgical repair can usually be undertaken on the basis of echocardiographic diagnosis alone. Echocardiography also provides an extremely accurate method of evaluating surgical repair and of identifying and localizing postoperative obstruction to pulmonary venous return.

Cardiac Catheterization↗
PubMed1991

The adult with congenital heart disease: cardiac catheterization as a therapeutic intervention.

The adult with congenital heart disease who undergoes cardiac catheterization at the present time is most likely to have complex heart disease and is left with clinically important sequelae or residual defects, ventricular dysfunction or arrhythmias. Residual defects such as paravalvular leaks, coronary fistulas and pulmonary artery narrowings may be corrected with transcatheter techniques. Patients with simple forms of congenital heart disease (for example, atrial septal defect, patent ductus arteriosus, aortic valve stenosis, pulmonary valve stenosis) will go to the catheterization laboratory for treatment, not diagnosis. Certain lesions previously considered benign (for example, patent foramen ovale) may require definitive interventional therapy to reduce the risk of stroke from paradoxic embolism.

Adult↗
PubMed1991

Use of endovascular stents in congenital heart disease.

BACKGROUND: Balloon expandable intravascular stents have been used to support vessel walls in coronary and peripheral arteries in adults. The purpose of this study was to examine the efficacy and safety of these stents in the treatment of congenital heart disease. METHODS AND RESULTS: Forty-five stents were placed in 30 patients, who were 0.2-30.2 years old (weight, 3.5-76 kg). Patients with areas of stenosis that were difficult to approach surgically were chosen. Stents were mounted over balloons and placed by standard catheterization techniques. Twenty-three patients had branch pulmonary artery stenosis. Thirty-six stents were placed successfully and had reduced pressure gradients from 50.6 +/- 24 to 15.9 +/- 13.4 mm Hg. Five patients had stents placed after atrial surgery: three in obstructed Fontan repairs, one at the superior vena cava-right atrial junction after sinus venous defect repair, and one at the site of a Glenn shunt. Atrial stents reduced pressure gradients from 9.8 +/- 8.2 to 2.0 +/- 2.6 mm Hg. One patient had a stent placed in the descending aorta after coarctation dilation, and the pressure gradient was reduced from 50 to 25 mm Hg. One patient had pulmonary vein dilation with stent placement. Two stents migrated at the time of placement; one required surgical removal, and one was anchored in place by balloon dilation. One patient died within 24 hours of catheterization because of thrombus obstruction of the Fontan repair. Nine patients have undergone recatheterization. All stented vessels have remained at the same caliber as at original stent placement. CONCLUSIONS: We conclude that balloon expandable stents are useful in selected postoperative stenoses in congenital heart disease.

Adolescent↗
PubMed1991

Myocardial angiogenesis and coronary perfusion in left ventricular pressure-overload hypertrophy in the young lamb. Evidence for inhibition with chronic protamine administration.

In contrast to young growing animals, pressure-overload hypertrophy in adults is frequently associated with diminished myocardial capillary density and maximal coronary flow per gram. To determine the role of angiogenesis in maintaining perfusion capacity in the hypertrophying heart, the angiogenesis inhibitor protamine sulfate was administered to young lambs during the development of left ventricular (LV) pressure-overload hypertrophy. Baseline and maximum (adenosine) myocardial perfusion was measured in four groups of chronically instrumented 10-week-old lambs subjected to 1) ascending aortic bands since the age of 4 weeks (LVH group, n = 10), 2) sham operation at the age of 4 weeks (SHAM group, n = 8), 3) aortic bands and twice daily injections of protamine since the age of 4 weeks (LVH + P group, n = 9), 4) sham operation and injection of protamine (SHAM + P group, n = 8). Capillary density was measured postmortem. Peak LV pressure and the LV/body weight ratio were similarly increased in LVH and LVH + P compared with sham-operated lambs (p less than 0.001). In LVH lambs, LV capillary number increased by 32% compared with sham-operated lambs (p less than 0.05), and capillary density, coronary flow reserve, and minimal coronary resistance remained normal. In contrast, LVH + P lambs had no significant increase over SHAM lambs in LV capillaries and total maximum coronary flow. The LVH + P lambs had lower LV subendomyocardial capillary density and higher minimal coronary resistance per gram (p less than 0.05 versus LVH lambs). Right ventricular capillary density and minimal resistance were similar in all groups. These findings support the hypotheses that myocardial angiogenesis with pressure-overload hypertrophy is important in maintaining maximal LV coronary flow in the young and that impairment of angiogenesis results in diminished coronary flow capacity.

Age Factors↗
PubMed1990

Balloon angioplasty for congenital mitral stenosis.

We attempted balloon angioplasty in 9 children (ages 0.1 to 10 years) with congenital mitral stenosis. All were symptomatic with severe congestive heart failure and failure to thrive. Effective reduction in mitral gradient was initially achieved in 7 patients. For the entire group, mean valve gradient decreased from 14.8 +/- 5.0 to 8.1 +/- 6.7 mm (p = 0.0007) and mean valve area increased from 1.1 +/- 0.5 to 1.8 +/- 0.9 cm2/m2 (p = 0.003). More than mild mitral regurgitation developed in 2 patients but none required surgery for mitral regurgitation. Poor gradient relief followed dilation of valves with unbalanced chordal attachments, with restriction to the valve apparatus as in mitral arcade, and where the obstruction was not purely valvar as it is with a supramitral ring. No strokes, infection or deaths were due to the procedure. Based on these data, balloon angioplasty of congenital mitral stenosis should be considered before mitral valve replacement in younger patients and in those in whom mitral valve replacement would be problematic.

Angioplasty, Balloon↗
PubMed1990

The "laid-back" aortogram: an improved angiographic view for demonstration of coronary arteries in transposition of the great arteries.

Preoperative demonstration of coronary arterial anatomy may be important for babies undergoing the arterial switch operation. Echocardiography is clearly useful, but may not unequivocally show all coronary branches. Standard angiographic views can be confusing. An improved angiographic projection in which the frontal x-ray tube is caudally angled, resulting in a "laid-back" position of the image intensifier and cine camera, provides superior visualization of the coronary arteries and their relation to the aorta and the pulmonary artery. The balloon occlusion technique is used for opacification of the aortic root from the transvenous approach. Injection of 1 ml/kg of contrast delivered in 1/2 to 1 second provides the best images. The caudal aortogram is easier to interpret than standard views and facilitates description and recognition of various coronary patterns. The relation between the pulmonary artery and the aorta, the origins of the coronary arteries from the facing sinuses and their proximity to the intercoronary commissures, and the myocardial distribution of each coronary vessel are shown clearly. The caudal view therefore offers significant advantages over conventional projections for demonstration of coronary arterial anatomy in infants with transposition of the great arteries or double-outlet right ventricle.

Aortography↗
PubMed1990

Systemic heparinization does not prevent clot formation in coil embolization.

Therapeutic transcatheter closure with Gianturco-type steel coils has been applied to a variety of vascular communications in children with congenital heart disease. Vessel closure depends upon successful thrombus formation around the coil. Since systemic anticoagulation with heparin is commonly used during catheterization and cardiac surgery, we studied the effect of systemic heparinization on the efficiency of vessel occlusion by coil embolization in lambs. Catheters inserted in femoral arteries were used to arteriographically locate and size 36 systemic arteries in 9 lambs weighing 4.2 to 7.4 kg. Twenty-four vessels were embolized prior to heparinization with 400 u/kg heparin, IV. Effective anticoagulation was demonstrated by post-heparin activated clotting time (ACT) values greater than 300 sec. Seven vessels (29%) were not successfully coil-embolized because of inadequate coil position or distant embolization of the coil; 17 (71%) of these vessels were shown to be successfully occluded by arteriography 6 to 77 min later. After a period of systemic heparinization ranging from 71 to 159 min, 9/17 arteries remained occluded, 7/17 could not be examined arteriographically due to early demise of the animal, and only 1/17 showed recanalization. A second group of 12 vessels were embolized after heparinization. Eight (75%) were successfully occluded, and 4 (25%) were not successfully coil-embolized because of inadequate coil position or coil embolization to distant arteries. We conclude that systemic heparinization had no measurable effect on occlusion rates in coil-embolized systemic arteries in the lamb. These data support the use of systemic heparinization, when indicated, during or following therapeutic coil embolization in children.

Animals↗
PubMed1990

Early results and follow-up of balloon angioplasty for branch pulmonary artery stenoses.

Two hundred eighteen balloon angioplasty procedures were performed in 135 patients with branch pulmonary artery stenoses from June 1984 to February 1989. Arteries were dilated in patients with tetralogy of Fallot (n = 49), tetralogy of Fallot/pulmonary atresia (n = 64), isolated peripheral pulmonary artery stenoses (n = 58) and "other" lesions (the majority had truncus arteriosus or single ventricle and surgically induced pulmonary artery stenoses (n = 47). Mean age at dilation was 6.6 +/- 6.3 years (range 1 month to 38.5 years). The mean diameter of the lesion increased from 3.8 +/- 1.7 to 5.5 +/- 2.1 mm with dilation (p = 0.001). The overall success rate was 58% (127 of 218 dilations), assessed by the following criteria: an increase greater than or equal to 50% of predilation diameter, an increase greater than 20% in flow to the affected lung or a decrease greater than 20% in systolic right ventricular to aortic pressure ratio. Success did not correlate with patient age. Mean balloon to artery ratio was higher in successful (4.2) than in failed (3.0) angioplasty procedures (p = 0.0001). There were four early deaths: two of the patients had pulmonary artery rupture with angioplasty performed less than 1 month after pulmonary artery surgery. An aneurysm occurred in 11 arteries and transient pulmonary edema in four patients. At angiography performed a mean of 10 months (range 1 to 54) after dilation, the mean diameter of 57 arteries was unchanged (5.5 versus 5.4 mm). However, 5 of 32 initially successfully dilated vessels had returned to predilation size as a result of restenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Double-umbrella closure of atrial defects. Initial clinical applications.

Forty patients were catheterized for closure of atrial septal defects with the Rashkind patent ductus arteriosus umbrella device, a modified Rashkind umbrella device, and the newly designed Lock Clamshell Occluder. Patients weighed 8 kg or more (a requirement for transvenous access with the 11F delivery sheath) and had defects suitable for closure based on two-dimensional echocardiography. The new device was at least 1.6 times the diameter of the atrial septal defect as determined by balloon sizing at catheterization. Patients were followed up by telephone, clinical examination, and echocardiography at 6 months. We attempted closure in 34 patients, with atrial septal defects ranging in diameter from 3 to 22 mm; device sizes ranged from 17 to 33 mm. Initial device position immediately after release was correct in all patients. A cerebral embolus occurred in one elderly patient before device placement--the patient died 1 week later. Two instances of early device embolization occurred, and devices were retrieved by catheter without complication. Follow-up of 31 patients discharged with devices in place, for a total of 31 patient-years, has yielded no umbrella-related complications. Adequate imaging studies in 19 patients 6.5 months after device placement revealed no atrial shunt in 12; residual flow through separate, previously unrecognized atrial septal defects occurred in two; and small residual leaks (less than 3 mm) around devices were present in five patients. This initial success indicates that double-umbrella closure of atrial septal defects will aid in the treatment of intracardiac defects.

Angiography↗
PubMed1990

Baffle fenestration with subsequent transcatheter closure. Modification of the Fontan operation for patients at increased risk.

Ventricular dysfunction, elevated pulmonary vascular resistance, and residual distal pulmonary artery distortion contribute to early mortality after a Fontan operation; they may be transient or reversible. A baffle fenestration, allowing right-to-left shunting, maintains cardiac output and limits right atrial pressure. A baffle fenestration was surgically created at the time of a modified Fontan repair in 20 consecutive patients. Risk factors included pulmonary artery pressure of 18 mm Hg or more, end-diastolic pressure of 12 mm Hg or more, valvar regurgitation, pulmonary artery distortion, pulmonary vascular resistance of 2 Woods' units or more, ventricular outflow obstruction, and complex anatomy. Nineteen of 20 patients survived. After the operation, mean arterial oxygen saturation was 86%, mean right atrial pressure was 15 mm Hg, and mean duration of pleural effusions was 6 days. Twelve of 19 survivors tolerated early test occlusion and had permanent transcatheter umbrella closure. Four patients failed early test occlusion, with a significant decrease in venous O2 saturation and a rise in central venous pressure, due to ventricular dysfunction, pulmonary artery distortion, or aortopulmonary collaterals. Three of four had successful late closure of the fenestration after correction of these abnormalities.

Cardiac Catheterization↗
PubMed1990

Balloon dilation of branch pulmonary artery stenosis.

We consider balloon angioplasty to be an established, highly useful procedure in the management of branch pulmonary artery stenosis. It is successful in approximately 60% of cases. Current figures would indicate a low but significant mortality rate (1%) and a risk of aneurym formation (3%). Patients undergoing balloon angioplasty in the acute postpulmonary artery surgical period constitute a particularly high risk group for vessel rupture. Restenosis after branch pulmonary dilation is infrequent, but does occur. Further improvements in the use of this procedure should probably involve the use of expandable intravascular stents for patients with failed dilations or evidence of restenosis.

Aneurysm↗