Persistent stenosis and deformity of the right pulmonary artery after correction of the Waterston anastomosis

Types of anatomic relationship between left main coronary artery and pulmonary sinus of Valsalva: Implications for balloon pulmonary angioplasty and catheter ablation in the pulmonary root

BACKGROUND

Concerns have been raised upon the risk of left main coronary artery (LMCA) injury when balloon angioplasty or ablation is performed within the pulmonary sinus of Valsalva (PSV).

OBJECTIVE

To investigate the LMCA and PSV anatomic relationship (LMCA-PSV_ar) variants potentially susceptible to procedure complication.

METHODS

We retrospectively studied 100 consecutive patients undergoing computed tomography coronary angiography (CTCA). Three types of LMCA-PSV_ar were observed on the basis of the relative location between the LMCA ostium and left pulmonary sinus of Valsalva (LPSV): type 1, intimate contact between the LMCA ostium and LSPV; type 2, LMCA ostium opposite to LPSV and the proximal part coursing anteriorly around LSPV; and type 3, no contact between LMCA ostium and LSPV.

RESULTS

LMCA-PSV_ar types 1, 2, and 3 were present in 20(20%), 43(43%), and 37(37%) patients, respectively. For the three types of LMCA-PSV_ar, the minimal distance between LMCA and LPSV was 1.66 ± 0.53 mm, 4.63 ± 1.64 mm and 8.24 ± 1.65 mm, and the distance ≤5 mm were in 100%, 87% and 9% patients, respectively. Additionally, the distance from right coronary artery (RCA) to right pulmonary sinus of Valsalva (RPSV)/RVOT was ≤5 mm in 71 patients (71%).

CONCLUSION

The LMCA is intimately related to LPSV in majority of patients (mainly involving the types 1 and 2), whereas the RCA is often close to RPSV/RVOT. These anatomic features pose potential vulnerability to coronary injury, and should be heightened to avoid complications in this area.

Balloon Angioplasty as a Modality to Treat Children with Pulmonary Stenosis Secondary to Complex Congenital Heart Diseases

BACKGROUND

Pulmonary stenosis is common in children with complex congenital heart diseases. Proper management of this problem, especially postoperatively, is still controversial. This study was designed to assess the rate and determinants of success or failure of balloon angioplasty for such lesions.

METHODS

Clinical and hemodynamic data from 40 pediatric patients (24 boys and 16 girls) with complex congenital heart diseases who underwent balloon angioplasty were reviewed retrospectively from January 2012 to December 2016. Patients were divided into four groups according to the site of stenosis, which included pulmonary valve stenosis (PVS), valved conduit stenosis, pulmonary artery stenosis (PAS), and supravalvular pulmonary stenosis (SVPS). Success rates were calculated according to defined criteria for initial success and favorable clinical impacts, and comparison between the successful subgroup and the unsuccessful subgroups was analyzed.

RESULTS

Grouped by the site of stenosis, initial success rates varied from 40.0% to 52.4% with the greatest success being seen in the PVS group, followed by the PAS group and SVPS group. In the PVS group and the PAS group, there was no statistical difference among age at dilation, postoperative interval, balloon/stenosis ratio, or pressure gradient predilation between the successful and the unsuccessful subgroups. Favorable clinical impacts included success rates of balloon angioplasty in the SVPS group, which was best (100%), followed by the PVS group (90.9%) and the PAS group (85.7%). There were a total of two transient complications (5.0%).

CONCLUSIONS

Balloon angioplasty was proven to be a safe and useful modality in children with complex congenital heart diseases and postoperative pulmonary stenosis, which should be the initial therapeutic modality in selected patients.

Per-operative stent placement in the right pulmonary artery; a hybrid technique for the management of pulmonary artery branch stenosis at the time of pulmonary valve replacement in adult Fallot patients

After having undergone surgical correction at an early age, many patients with tetralogy of Fallot develop long-term complications including progressive pulmonary regurgitation and peripheral pulmonary stenosis. A high percentage of these patients need to undergo a second operation in their adolescence or early adulthood. If simultaneous treatment of both pulmonary regurgitation and peripheral pulmonary stenosis is warranted, a complete surgical approach has several disadvantages. We describe four cases of Fallot patients with severe pulmonary regurgitation and peripheral pulmonary stenosis who were treated using a hybrid approach involving surgical implantation of a pulmonary homograft and peroperative stenting of the pulmonary artery.

[Stent dilatation of pulmonary artery stenosis in the adult patient with congenital heart disease]

Stents have been previously used to resolve stenoses of branch pulmonary arteries in children. We report 3 patients, with mean age of 22.7 +/- 4.7 years and pulmonary artery stenosis after palliative surgery in whom we implanted seven stents in four procedures. Six P308 Palmaz, overlapped two by two, were implanted by venous femoral approach in two patients, receiving four in the first case and the other two in the third case. In the second case, a NIR type stent was implanted through femoral artery in the right pulmonary artery. Stenosis diameter enlarged from 5.3 +/- 2.3 to 14.4 +/- 4.2 mm and the pressure gradient through stenosis fell from 40.6 +/- 15.3 to 6. 5 +/- 5 mmHg. All stents are well deployed and there are two patients waiting for total correction (previously not feasible) during a follow-up of 30.6 +/- 6.1 months.

Ascending aortic extension for right pulmonary artery stenosis associated with ventricular-to-pulmonary artery conduit replacement

BACKGROUND

Ventricular-to-pulmonary artery conduits in growing patients with congenital heart disease will require replacement from time to time due to somatic growth, neointimal hyperplasia, and pulmonary artery stenosis. The purpose of this article is to review our experience with ascending aortic extension for significant long-segment pulmonary artery stenosis in patients undergoing reoperation for right ventricular-to-pulmonary artery conduit replacement.

METHODS

From 1989 to 1997, 8 patients had aortic transection, right pulmonary artery augmentation arterioplasty, and aortic interposition graft (Hemashield in 7 and Gore-tex in 1) in association with right ventricular-to-pulmonary artery conduit replacement in 7 patients and completion Fontan operation in 1 patient. Aortic cross-clamp time was 90 +/- 34 minutes, and the cardiopulmonary bypass time was 205 +/- 37 minutes.

RESULTS

All patients survived. In those 7 patients who had conduit replacement, the RV/LV ratio declined from 0.78 +/- 0.15 to 0.45 +/- 0.05 postoperatively (P < 0.05). Average length of stay was 8.9 +/- 7.2 days. Follow-up range is 18 months to 8 years (mean 4 years). Two complications included cardiac transplantation for pre-existing poor left ventricular function and accelerated conduit stenosis leading to conduit re-replacement.

CONCLUSION

Ascending aortic extension facilitates long-segment pulmonary artery augmentation arterioplasty and enlarges the retroaortic space, preventing future compression restenosis.

Lay-open pulmonary arterioplasty for postoperative hilar pulmonary artery stenosis

OBJECTIVE

Lay-open pulmonary arterioplasty, a novel surgical technique to enlarge postoperative stenosis at the hilar pulmonary artery, was evaluated.

METHODS

Lay-open arterioplasty, in which the enlarged hilar stenotic pulmonary artery is partially made up of previous surgical scar tissue instead of being covered by a patch, was performed on 10 patients whose ages ranged from 2.2 to 15.7 years. Surgical results were assessed by angiography.

RESULTS

All patients tolerated the procedure without bleeding or embolic complications associated with pulmonary arterioplasty. Nine patients underwent concomitant procedures including total repair (n = 5), central interposing shunt (n = 3), and right ventricular outflow tract reconstruction (n = 1). No deaths or life-threatening events occurred during the total follow-up period of 18 patient-years. The stenotic segment was significantly enlarged from the preoperative diameter of 0.9 +/- 1.1 mm (mean +/- standard deviation) to the postoperative diameter of 8.0 +/- 1.3 mm, values which correspond to 7.0% +/- 8.8% and 68.4% +/- 11.5% of the normative values, respectively. A follow-up angiogram (n = 5) revealed an increase in the pulmonary artery diameter balanced with somatic growth (initial value, 65.2% +/- 9.0% of normal; second value, 69.1% +/- 7.7% of normal). No aneurysms or clinically significant restenoses were seen on the angiograms.

CONCLUSIONS

Our initial midterm results with this method were promising. The pulmonary arteries subjected to this procedure grew in proportion to somatic growth.

Endovascular stents in congenital heart disease

Acquired or de novo vascular obstructions can adversely affect the outcomes of management algorithms for children with congenital heart lesions. Although surgical repair is frequently feasible, some acquired or congenital obstructions are difficult to address in the operating theater. Presented is the recent experience with endovascular stents to relieve such stenoses, and their impact on patient care.

Balloon-expandable stenting in pediatric cardiology

Intravascular stent placement in Pediatric Cardiology has provided one of the most interesting and effective means of catheter treatment of congenital lesions. In the 5 years since it has been performed, balloon-expandable stent placement has provided relief of many previously untreatable vascular stenoses and has resulted in improvement of blood flow, reduction of right ventricular pressure and, in many cases, dramatic improvement of symptoms. In this article, the background of balloon-expandable stent placement is discussed, and specific observations are offered regarding the technique of implantation. The generally excellent results are presented and a number of novel problems and pitfalls are outlined. Finally, a brief summary of the wide ranging applicability of stent implantation is discussed, along with some of the important and imaginative new directions for the therapy.

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.

Intravascular stents for management of pulmonary artery and right ventricular outflow obstruction

This study was performed to determine the efficacy of balloon-expandable stents in the treatment of branch pulmonary artery-stenoses and conduit stenosis in children. A total of eight stainless steel stents were implanted in seven patients. Three patients had tetralogy of Fallot with pulmonary artery stenosis following total correction, one patient had conduit stenosis following correction of transposition of the great arteries, one patient had intra-cardiac conduit stenosis after septation for single left ventricle, and two patients had pulmonary artery stenosis after Fontan operation. Six stents were placed in the branch pulmonary arteries, one in the extracardiac conduit, and one in the intracardiac conduit. The mean age at implantation was 13 +/- 3 years and the mean weight 37 +/- 12 kg. Follow-up time ranged from 0.3-2 years. The diameter of pulmonary arteries with stenoses increased from 5.6 +/- 2.2 mm to 10.6 +/- 1.8 mm (n = 7). The systolic pressure gradient decreased from 56 +/- 26 mmHg to 22 +/- 16 mmHg (n = 5). No embolization or thrombotic event has been noted. One stent placed in the intracardiac conduit was compressed and fractured. These data indicate that balloon-expandable stents are useful in the treatment of pulmonary artery branch stenoses and extracardiac conduit stenosis in children. The use of stents for intracardiac stenosis may result in stent fracture.

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.

Use of balloon-expandable stents to treat experimental peripheral pulmonary artery and superior vena caval stenosis: preliminary experience

Current therapy of congenital or acquired stenoses of the peripheral pulmonary arteries and superior vena cava are frequently ineffective. This report describes our initial experience with the use of a balloon-expandable stainless steel stent to treat experimentally created branch pulmonary artery and superior vena cava stenosis. Fifteen adult mongrel dogs had surgically created stenoses of either a branch pulmonary artery and/or superior vena cava. A balloon-expandable stainless steel (0.076 mm), 3 cm long, intravascular stent was used in all animals. Stents were successfully placed in 13 of 15 dogs (nine with branch pulmonary stenosis and four with superior vena caval stenosis) with hemodynamic and angiographic relief of the stenoses in all. In three animals, successful stent placement was not accomplished because the distal right pulmonary artery was found to be totally obstructed in two and in one dog with combined vena cava and pulmonary stenosis the distal right pulmonary artery was so severely stenotic that the stenosis could not be crossed. Repeat catheterization performed 6 months following stent placement documented persistent gradient relief and angiographic evidence of unobstructed flow through the stent without thrombus formation and with patent side branch vessels. Our preliminary results suggests that balloon-expandable stents are a potential therapy for the treatment of branch pulmonary artery and superior vena cava stenoses.

Percutaneous implantation of a balloon-expandable endoprosthesis for pulmonary artery stenosis: an experimental study

Conventional therapy to treat peripheral pulmonary artery stenosis (surgery or balloon angioplasty) has been frustrating. Recently a variety of peripheral vascular stenoses, in which conventional approaches are disappointing, have become amenable to therapy with the use of a balloon-expandable endovascular stent. This experimental study was designed to assess the application of such a prosthesis in artificially created pulmonary artery stenoses. In 9 of 12 2-week old pigs, left pulmonary artery stenosis was surgically created (3.9 +/- 1.1 mm diameter and 7 +/- 1 mm Hg mean gradient). At 6.8 +/- 1 weeks of age (13 +/- 4 kg), percutaneous (femoral venous) implantation of a 3-cm long balloon-expandable (maximal diameter 18 mm) stent (three placed into normal pulmonary artery branches) using a 3-cm x 10-mm balloon dilating catheter was achieved without technical difficulties. Stenoses were enlarged to 8.3 +/- 1.4 mm with a decrease in mean gradient to 1 +/- 1 mm Hg that was maintained through 3.5 months of follow-up. Histologic and electron micrographic studies identified normal-appearing neoendothelial layering over stent struts without intraluminal or peripheral thrombus formation and nonobstructed side branching to lung subsegments. These findings support the application of this approach in the treatment of pulmonary stenosis that is not amenable to conventional therapy.

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.

Lord Brock--the direct approach

The contributions of Sir Russell Brock to the early development of cardiac surgery are multiple. However, one of the most telling was his description of 3 cases of pulmonary stenosis in 1948 treated by direct transventricular valvulotomy. His subsequent treatise, The Anatomy of Congenital Pulmonary Stenosis, published in 1957, outlined this direct approach to cardiac lesions, a philosophy commonly adopted in modern care of cardiac lesions and a major contribution to cardiac surgical thinking.

Implantation of balloon-expandable intravascular grafts by catheterization in pulmonary arteries and systemic veins

The purpose of this investigation was to evaluate the efficacy and safety of implanting expandable intravascular stents in pulmonary arteries and systemic veins. Twenty-seven balloon-expandable grafts were placed in 13 mongrel dogs under anesthesia. A long sheath was introduced over a wire and catheter or dilator into the pulmonary artery or target vein. A collapsed stainless steel expandable mesh stent was placed over the balloon of an angioplasty catheter. The catheter with the mounted stent was advanced through the sheath. The stent expanded to the diameter of the balloon as the balloon was inflated, and remained expanded as the balloon was deflated. The stent was expanded further with a larger balloon in 11 instances. Eleven stents were placed successfully in pulmonary arteries (out of thirteen attempted), and 11 of 14 were installed in tributaries of the precava or postcava. Three inadvertent embolizations of the devices occurred. All three devices that embolized lodged in the pulmonary arteries and did not obstruct flow. Seven dogs were recatheterized at intervals ranging from 56 to 278 days. Twelve stents were patent and nonobstructive, and two were malpositioned, one of which was obstructed. Three animals were killed 2 months (two dogs) and 9 months (one dog) after the implantations. The stents (four in the pulmonary arteries and two in veins) were completely covered with neointima and were patent, without thrombosis. These stents hold promise for definitive dilation of congenital or postoperative vessel stenoses.

Palliation in cyanotic congenital heart disease. Fifteen years' experience of various shunt procedures

During the past 15 years, 143 systemic pulmonary shunt procedures have been performed in 117 patients. These have been evaluated for their clinical effectiveness, the need for a repeat operation and the mortality; particular attention was paid to the Teflon shunt. Variations were found in shunt performance, depending on the primary defect, the type of shunt that was employed and the year of operation. The overall shunt patency after three years was 77% (85% with the Teflon shunt). Although, in our total experience, mortality at 30 days was 12%, with 16% late deaths, "modified Blalock" (Teflon) shunts had only a 5% hospital mortality and a 5% late mortality within three years. Pulmonary atresia, without a ventricular septal defect, is often insufficiently palliated by a shunt alone. Ten of 82 patients with variations of the tetralogy complex died within 30 days of operation, and a further 11 died in the late follow-up period. Six of these 21 shunts were patent at autopsy. Less common defects, such as univentricular heart, transposition and double-outlet right ventricular connections, that are associated with pulmonary stenosis had no early mortality but led to four late deaths among 27 patients. Two of the four patients had patent shunts. Results in the early part of this experience were less than acceptable owing to inferior shunting techniques, postoperative management errors and, particularly, inadequate follow-up surveillance. With correction of these factors we find that the modified Blalock shunt provides very good early and late mortality results, with excellent clinical palliation and patency rates.

Use of balloon angioplasty to treat peripheral pulmonary stenosis

Balloon angioplasty was attempted in 13 children with peripheral pulmonary arterial (PA) stenosis. In 5 patients, angioplasty was successful in relieving the peripheral PA stenosis as judged by an increase in PA size of more than 75% over the predilatation size and a more than 50% reduction in the distal PA to main PA peak systolic pressure gradient. Each child has been followed for 6 to 30 months. All remain well, without signs of subsequent deterioration, and follow-up angiograms in 2 patients (at 10 and 12 months) showed persistence of anatomic and hemodynamic improvement. In 8 patients, angioplasty was unsuccessful: In 4 patients, stenosis at the site of a previous systemic-to-PA shunt could not be dilated and in 4 patients, angioplasty could not be performed because of technical difficulties. Thus, we could not dilate the stenosis in more than 60% of the patients; we also had a significant complication with the angioplasty procedure (perforation of a distal branch of the right pulmonary artery). Thus, although balloon angioplasty was not effective in all patients, it did provide significant improvement in some patients in whom traditional operative management is usually unsuccessful.

Subclavian-pulmonary artery shunts with polytetrafluorethylene interposition grafts

Systemic-pulmonary artery shunts remain an important treatment in cyanotic patients. Central shunts continue to pose early and late problems when standard Blalock-Taussig shunts are not possible. Twenty patients underwent subclavian-pulmonary artery shunt procedures with polytetrafluoroethylene (PTFE) prostheses between October, 1980, and August, 1982. Their ages ranged from 1 day to 15 years; 11 patients were less than 14 days old. The arterial oxygen tension rose from 30.7 +/- 11.9 mm Hg to 51.3 +/- 9.1 mm Hg (standard deviation; p less than 0.001) and from 26.4 +/- 7.5 mm Hg to 50.5 +/- 9.3 mm Hg (p less than 0.001) among the 11 neonates. There were no hospital deaths and only 2 late deaths (not shunt related). All patients have patent shunts and excellent relief of cyanosis. The 18 survivors have been followed for an average of 19 months (range, 7 to 29 months). No patient has required reoperation for shunt inadequacy or thrombosis. Recatheterization in 11 patients has demonstrated normal pulmonary pressures and good pulmonary artery growth without vessel distortion. Subclavian-pulmonary shunts using PTFE provide long-term palliation in cyanotic patients. This type of shunt appears to offer important advantages over other shunt procedures, including the classic Blalock-Taussig operation, in newborns.

Balloon dilation angioplasty of hypoplastic and stenotic pulmonary arteries

Balloon dilation angioplasty (BDA) was attempted in seven children with either stenosis or hypoplasia (a narrowing greater than 1 cm long extending past the lung hilum) of both right and left pulmonary arteries (PAs). In two of these seven, the procedure could not be performed because of technical difficulties. In each of the remaining five children (1 1/2-16 years old), the right ventricular (RV) pressure was greater than 2/3 left ventricular pressure, main PA pressure was greater than 60 mm Hg, and previous operative attempts to relieve RV outflow obstruction, including the branch PA obstruction, were unsuccessful. BDA was performed in only one PA in each patient, and was considered successful if the pressure gradient decreased, angiographic diameter increased and the percentage of blood flow directed to the dilated lung increased. BDA was successful in all five children: RV pressure fell from 104 +/- 42 to 80 +/- 30 mm Hg (p less than 0.05), the gradient across the obstruction fell from 61 +/- 51 to 32 +/- 22 mm Hg (p less than 0.05), the diameter of the narrowed segment increased from 3.7 +/- 1.2 to 6.8 +/- 1.1 mm, p = 0.02), and the percentage of blood flow (as determined by quantitative lung scan) to the dilated lung increased from 41 +/- 16% to 52 +/- 22% (p less than 0.05). No morbidity was observed in any patient. Follow-up angiograms (2-12 months) in three of five patients indicate persistence of the anatomic improvement. While BDA did not restore right-heart pressures and anatomy to normal, it provided significant hemodynamic relief to a group of patients in whom traditional operative management has usually been unsuccessful. Final determination of the role of BDA in such patients must await the results of further studies.