New developments in pediatric interventional heart catheterization.
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Biomedical subjects
Publications and source records attributed to J E Lock.
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The currently available interventional cardiac procedures in neonates and infants are at various stages of development. We currently dilate neonates and infants with critical valvular pulmonary and aortic stenosis and postoperative aortic obstruction. We do not routinely dilate native coarctation of the aorta because of the possibility of aneurysm formation, unless the neonate is very sick and acidotic and an operative approach is considered to be high risk. Balloon and blade atrial septostomy are done routinely whenever indicated with a low incidence of morbidity. Coil embolization, endomyocardial biopsy, foreign body retrieval and percutaneous pericardial drainage are relatively safe, and with the currently available instruments these techniques can be performed safely in neonates and infants with the same indications as for older patients. We currently consider stenotic pulmonary veins to be an undilatable lesion and an optimal therapy remains to be defined. Transcatheter closure of PDA and intracardiac shunts is presently limited to older patients, due to the large size of the delivery system devices and cannot currently be used in neonates. Dilation of the pulmonary valve in cyanotic congenital heart disease appears useful, but further experience is needed.
Although therapeutic catheter procedures for congenital heart disease are still developing, the number of procedures being performed allows statistically relevant review of the acute complications. Between January 1, 1984, and February 1, 1987, 417 such procedures were performed at The Children's Hospital, Boston; the age range of the patients was 1 day to 51 years (median 4 years, 6 months). Catheter procedures consisted predominantly of vascular dilations (peripheral pulmonic stenosis, 97; valvular pulmonic stenosis, 67; valvular aortic stenosis, 62; recurrent coarctation, 49) and embolizations (double umbrella device, 36; steel coils, 45). Overall, there were 50 acute complications (12%); 24 (6%) were major and 26 (6%) were minor. The mortality rate was 3 of 417 (0.7%). Complication rates varied between 4% for dilation of recurrent coarctation and 40% for dilation of aortic stenosis. The age of the patients was a factor in complications of vascular access (11 patients), 8 of which occurred in patients younger than 6 months (median 5), and in cardiac arrest and ventricular fibrillation (4 patients, 3 of whom were younger than 6 months [median 3]). No statistically significant trend toward diminishing overall complication rates was discerned over the 37 months of this study.
Balloon dilation angioplasty (BDA) was attempted 29 times in 27 patients, aged 3 months to 22 years, with postoperative aortic obstructions. Previous operations included end-to-end anastomosis (n = 10), subclavian flap angioplasty (n = 7) and patch angioplasty (n = 3) for aortic coarctation, end-to-end anastomosis for interrupted aortic arch type B (n = 4) and aortic arch reconstruction for hypoplastic left heart syndrome (n = 3). Two of the patients with interrupted arch had multiple areas of obstruction. Balloon sizes were between 2 and 6 times the diameter of the lesion and up to twice the diameter of the proximal transverse arch (mean 1.1). BDA was at least partially successful (more than 50% decrease in gradient and more than 30% increase in diameter) in 26 of the 29 procedures (90%). BDA failed in the 2 lesions with an initial diameter of more than 8 mm. No differences were apparent in the success rate among any of the clinical groups. Peak systolic gradient decreased from 42 +/- 14 to 14 +/- 15 mm Hg (p less than 0.01) and mean diameter increased from 4.1 +/- 2.6 to 6.8 +/- 3.2 mm (p less than 0.01). There was no mortality or significant acute morbidity associated with the procedure. After 1 to 24 months of follow-up, restenosis has occurred in only 1 patient. Aneurysm formation was found in 2 of 5 patients who had undergone repeat catheterization; both aneurysms occurred in patients with repaired interruption of the aortic arch.(ABSTRACT TRUNCATED AT 250 WORDS)
Gianturco stainless steel coils were discharged into clear plastic tubes of varying sizes and subjected to pulsatile flow in order to study their behavior in a controlled, in vitro environment. When coils are too small for a given vessel, they tend to migrate distally or even proximally. Coils that are too large tend not to reform completely, limiting their cross-sectional area and potentially affecting their occlusive potential. Thus, each coil was tested in tubes of varying sizes and evaluated with regard to positional stability and extent of reformation.
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.
Preliminary reports have documented the utility of percutaneous balloon valvuloplasty of the mitral valve in adult patients with mitral stenosis, but the mechanism of successful valve dilation and the effect of mitral valvuloplasty on cardiac performance have not been studied in detail. Accordingly, mitral valvuloplasty was performed in five postmortem specimens and in 18 adult patients with rheumatic mitral stenosis, using either one (25 mm) or two (18 and 20 mm) dilation balloons. Postmortem balloon dilation resulted in increased valve orifice area in all five postmortem specimens, secondary to separation of fused commissures and fracture of nodular calcium within the mitral leaflets. In no case did balloon dilation result in tearing of valve leaflets, disruption of the mitral ring or liberation of potentially embolic debris. Percutaneous mitral valvuloplasty in 18 patients with severe mitral stenosis (including 9 with a heavily calcified valve) resulted in an increase in cardiac output (4.3 +/- 1.1 to 5.1 +/- 1.5 liters/min, p less than 0.01) and mitral valve area (0.9 +/- 0.2 to 1.6 +/- 0.4 cm2, p less than 0.0001), and a decrease in mean mitral pressure gradient (15 +/- 5 to 9 +/- 4 mm Hg, p less than 0.0001), pulmonary capillary wedge pressure (23 +/- 7 to 18 +/- 7 mm Hg, p less than 0.0001) and mean pulmonary artery pressure (36 +/- 12 to 33 +/- 12 mm Hg, p less than 0.01). Left ventriculography before and after valvuloplasty in 14 of the 18 patients showed a mild (less than or equal to 1+) increase in mitral regurgitation in five patients and no change in the remainder.(ABSTRACT TRUNCATED AT 250 WORDS)
To evaluate the risks of and optimal method for valve dilation in aortic stenosis, balloons of different sizes were used to dilate the normal aortic root in 16 lambs and then stenotic valves in 15 children. In the lambs, inflated balloon to aortic anulus diameter ratios ranged from 0.9 to 1.5. These hearts were examined immediately after the procedure. Ratios of 0.9 to 1.1 did not produce significant damage to the left ventricular outflow tract, whereas those of 1.2 to 1.5 produced tears or hematomas, or both, of the aortic valve leaflets (n = 3), mitral valve leaflets (n = 4) and interventricular septum (n = 4). The 15 patients, aged 10 days to 15 years, underwent 16 balloon aortic valvotomy procedures. The balloon-aortic anulus ratio ranged from 0.67 to 1.1 (mean 0.90). The average pressure gradient decreased 69% and, overall, the peak systolic gradient decreased from 86 +/- 21 to 28 +/- 14 mm Hg (p less than 0.01) and the aortic valve area increased from 0.44 +/- 0.11 to 0.73 +/- 0.22 cm2/m2 (p less than 0.01). Immediately after the procedure an increase in aortic regurgitation was noted in 8 (57%) of 14 patients, but was never greater than 3+ and has been well tolerated. Other early complications encountered consisted of transient left bundle branch block in two patients, temporary femoral artery occlusion in three and femoral artery rupture requiring operative management in one infant. Balloon valvotomy can reduce the transvalvular gradient in most patients with valvular aortic stenosis when a balloon less than 1.1 times the aortic root diameter is used.(ABSTRACT TRUNCATED AT 250 WORDS)
Preliminary reports have documented the utility of balloon aortic valvuloplasty as a palliative treatment for high-risk patients with critical aortic stenosis, but the effect of this procedure on cardiac performance has not been studied in detail. Accordingly, 32 patients (mean age 79 years) with long-standing, calcific aortic stenosis were treated at the time of cardiac catheterization with balloon dilatation of the aortic valve, and serial changes in left ventricular and valvular function were followed before and after valvuloplasty by radionuclide ventriculography, determination of systolic time intervals, and Doppler echocardiography. Prevalvuloplasty examination revealed heavily calcified aortic valves in all patients, a mean peak-to-peak aortic valve gradient of 77 +/- 27 mm Hg, a mean Fick cardiac output of 4.6 +/- 1.4 liters/min, and a mean calculated aortic valve area of 0.6 +/- 0.2 cm2. Subsequent balloon dilatation with 12 to 23 mm valvuloplasty balloons resulted in a fall in aortic valve gradient to 39 +/- 15 mm Hg, an increase in cardiac output to 5.2 +/- 1.8 liters/min, and an increase in calculated aortic valve area to 0.9 +/- 0.3 cm2. Individual hemodynamic responses varied considerably, with some patients showing major increases in valve area, while others demonstrated only small increases. In no case was balloon dilatation accompanied by evidence of embolic phenomena. Supravalvular aortography obtained in 13 patients demonstrated no or a mild (less than or equal to 1+) increase in aortic insufficiency. Serial radionuclide ventriculography in patients with a depressed left ventricular ejection fraction (i.e., that less than or equal to 55%) revealed a small increase in ejection fraction from 40 +/- 13% to 46 +/- 12% (p less than .03). In addition, for the study group as a whole there was a decrease in left ventricular end-diastolic volume index (113 +/- 38 to 101 +/- 37 ml/m2, p less than .003), a fall in stroke-volume ratio (1.49 +/- 0.44 to 1.35 +/- 0.33, p less than .04), and no immediate change in left ventricular peak filling rate (2.05 +/- 0.77 to 2.21 +/- 0.65 end-diastolic counts/sec, p = NS). Serial M mode echocardiography and phonocardiography showed an increase in aortic valve excursion (0.5 +/- 0.2 to 0.8 +/- 0.2 cm, p less than .001), a decrease in time to one-half carotid upstroke (80 +/- 30 to 60 +/- 10 msec, p less than .001), and a small decrease in left ventricular ejection time (0.44 +/- 0.03 to 0.42 +/- 0.02 sec, p less than .001).(ABSTRACT TRUNCATED AT 400 WORDS)
Between October 1984 and September 1986, we attempted transcatheter umbrella closure, using the Rashkind PDA occluder, of 12 congenital or postoperative cardiovascular defects (other than patent ductus arteriosus [PDA]) in 11 patients. In each, we used the umbrella for closure because the defect was too short and/or too large to close with conventional transcatheter methods. The defects included three post-Glenn venous communications (superior vena cava-right atrium, n = 2; azygos vein to inferior vena cava), four congenital "interatrial defects" producing cyanosis ("coronary sinus" septal defect, left superior vena cava to left atrium, patent foramen ovale, left inferior vena cava to left atrium), and five non-PDA systemic-to-pulmonary arterial communications (two congenital and three postoperative). Ten of 12 defects were embolized successfully; nine had complete or subtotal closure, and one was partially closed. The first attempted closure resulted in embolization of a 12 mm device to a lower-lobe pulmonary artery, without clinical sequelae. No other complications occurred. Clinical improvement was most dramatic in those patients whose cyanosis was relieved and less obvious when pulmonary blood flow was reduced. The Rashkind umbrella device, originally designed for closure of PDA, considerably expands the list of congenital or operative defects that can be closed nonsurgically.
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We investigated whether or not a systemic arteriopulmonary shunt (SAPS) after 1 year of age affects a child's chances for a successful Fontan procedure. From 1967 to 1986, 50 patients more than 1 year old with tricuspid atresia or other complex lesions amenable to a Fontan operation received a SAPS. Follow-up was incomplete in six patients. Two patients died within 1 week of surgery, and two died within 9 months for a total mortality of 8%. Each of the 40 remaining patients was catheterized 6 months to 10.8 years (mean 4.9 years) after placement of a SAPS. By the criteria of Choussat and Fontan, there were one or more adverse SAPS-induced changes in nine patients (23%). Three developed pulmonary hypertension, one with associated elevation of pulmonary arteriolar resistance and pulmonary artery distortion, and one in conjunction with severe congestive heart failure. Six additional patients developed isolated distortion of the ipsilateral pulmonary artery. Of these nine patients, three had successful Fontan operations (33%), two died after the Fontan operation, and four are no longer candidates. In contrast, of 31 patients without documented SAPS-induced complications, 27 have undergone Fontan operations, 23 successfully (74%). Palliation with a SAPS after 1 year of age can place children at increased risk for a subsequent Fontan operation.
Patients with left atrioventricular (AV) valve atresia or stenosis were studied retrospectively to determine the incidence of early and late failures of procedures to enlarge an interatrial communication. The 61 patients underwent 80 procedures: 5 balloon atrial septostomies, 12 blade atrial septostomies and 63 surgical septectomies. No balloon septostomy provided adequate long-term palliation. Of 12 blade septostomies, 4 resulted in gradients across the atrial septum of 5 to 8 mm Hg and 8 in gradients 3 mm Hg or less. Results from blade septostomy were unrelated to underlying diagnosis, age, gradient before the procedure, number of previous procedures, pulmonary blood flow or size of the postprocedure defect by balloon sizing, but were related to size of the postoperative defect estimated by echocardiography. Among 8 patients with gradients of 3 mm Hg or less after blade septostomy, 7 were followed 9 +/- 7 months and showed no evidence of restenosis. Of 63 surgical septectomies, 11 (17.5%) were inadequate, and in at least 7 cases the failure was due to restenosis of the defect as documented by serial catheterizations or echocardiograms. Outcome after surgical septectomy was unrelated to underlying diagnosis, age or number of previous procedures, but was related to size of the defect created. Our results reveal improved results in terms of residual gradient for blade septostomy compared with previous studies and the need to follow these patients carefully, even those undergoing surgical septectomy.
The charts of 79 patients who required femoral arterial (FA) thrombectomy after cardiac catheterization were reviewed. Fifteen patients (19%) had poor pulses after thrombectomy and 2 had an extremity amputated. One thousand consecutive patients undergoing cardiac catheterization were also studied to prospectively determine the safety and efficacy of systemic fibrinolytic therapy for treatment of FA thrombosis. Among these, 771 patients underwent retrograde arterial catheterization, including 31 patients with left-sided obstructive lesions who had undergone transarterial balloon dilation procedures with large catheters. All patients were given heparin at the time of arterial cannulation. Patients who had a pulseless extremity 4 hours after catheterization continued to receive heparin therapy for 24 to 48 hours. If the extremity continued to have no palpable pulse and the systolic blood pressure was less than 50% of that in the contralateral leg, intravenous streptokinase infusion was begun. The overall incidence of FA thrombosis was 3.6% (28 of 771), including 39% (12 of 31) of all patients undergoing transarterial balloon dilation procedures; 97% (27 of 28) of patients weighed less than 14 kg and the majority weighed less than 10 kg. After an average treatment period of 33 hours, 16 patients continued to have a pulseless extremity and were treated with streptokinase for an average duration of 13 hours. Normal pulses and systolic blood pressure returned in 14 (88%) and were nearly normal in 1 other patient (6%). The incidence of bleeding at the arterial puncture site was 25% and was highest in the patients who had a transarterial balloon dilation procedure. No serious complications occurred.
Advances in cardiac surgery now enable many children with congenital heart disease (CHD) to survive to adulthood. The influence of such advances on the frequency of various lesions among adult patients undergoing cardiac catheterization (CC) has not previously been addressed. This retrospective analysis of 329 adults with CHD undergoing CC at an adult and at a pediatric referral center demonstrates that when compared to 20 years ago, adults with CHD who now undergo CC are more likely to have complex cardiac disease, and more have had prior surgery. In addition, despite more aggressive surgical management, ventricular dysfunction and dysrhythmias are now commonly encountered residua of CHD in adults who require diagnostic CC. Premature coronary artery disease appears uncommon. These changing characteristics of adults with CHD require consideration in the planning of future health care for these patients.
A 75 year old man with long-standing rheumatic mitral stenosis who refused surgical intervention was treated with percutaneous balloon valvuloplasty. Prevalvuloplasty evaluation revealed a heavily calcified mitral valve, a mean transvalvular gradient of 18 mm Hg, a Fick cardiac index of 1.7 liters/min per m2, a mitral valve area of 0.6 cm2 and 1 + mitral regurgitation. After transeptal catheterization and balloon dilation of the interatrial septum with an 8 mm angioplasty balloon, a 25 mm valvuloplasty balloon was advanced over a guide wire across the interatrial septum and positioned across the mitral anulus. Subsequent balloon inflation at 3 atm pressure resulted in a reduction of the mean mitral valve gradient to 12 mm Hg, an increase in cardiac index to 2.5 liters/min per m2, an increase in mitral valve area in 1.4 cm2 and an increase in mitral regurgitation from 1 + to 2 +. Valvuloplasty was well tolerated without embolization of clot or valvular debris, and resulted in marked clinical improvement with decreased dyspnea and increased exercise tolerance. Repeat catheterization 2 months after valvuloplasty showed further resolution of pulmonary hypertension and no evidence of valvular restenosis or worsening mitral regurgitation, but detected a small atrial septal defect with a pulmonary to systemic blood flow ratio of 1.8. It is concluded that percutaneous valvuloplasty is possible in the adult patient with calcific rheumatic mitral stenosis, and may result in a significant improvement in valvular function without producing life-threatening complications.
Percutaneous transvenous balloon mitral valvotomy was performed successfully in a 57 year old man with refractory congestive heart failure due to calcific mitral stenosis. Cardiac surgery was not an option because of other major medical problems. Balloon mitral valvotomy was performed using the transseptal technique. The interatrial septum was dilated with the use of an 8 mm balloon catheter to allow passage of larger balloon valvotomy catheters to the mitral anulus. The procedure resulted in a marked decrease in the diastolic transmitral gradient from 20 to 4 mm Hg. This decrease was associated with an increase in cardiac output from 3.4 to 5.7 liters/min. Mitral valve area increased from 0.7 to 2.5 cm2. Balloon valvotomy did not result in significant mitral regurgitation. This case indicates that further trials are warranted to evaluate percutaneous transseptal mitral valvotomy for the treatment of patients with mitral stenosis.
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