| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2007;84:1338-1342
© 2007 The Society of Thoracic Surgeons
a Division of Cardiac Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
b Division of Pediatric Cardiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
c University of Athens School of Medicine, Athens, Greece
Accepted for publication April 30, 2007.
* Address correspondence to Dr Mitropoulos, University of Athens School of Medicine, Monastiriou 8, Thracomacedones, Athens, 13676, Greece (Email: fotiosmitropoulos{at}yahoo.com).
Presented at the Forty-first Annual Meeting of The Society of Thoracic Surgeons, Tampa, FL, Jan 24–26, 2005.
 |
Abstract |
|---|
 Top Abstract IntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
Methods: We retrospectively analyzed data from 22 patients between 1998 and 2003 who underwent intraoperative pulmonary artery stenting.
Results: The mean age was 9.3 years (range, 9 months to 24 years). The left pulmonary artery was stented in 8 patients, the right in 13, the main in 1, and bilateral in 1. Available echocardiograms in 20 patients revealed a mean preoperative diameter of 7.6 mm (range, 3 to 16.5 mm) and a mean peak gradient of 45.4 mm Hg (range, 20 to 120 mm Hg). Augmentation patch angioplasty of the contralateral pulmonary artery was performed in 11 patients. Thirteen patients had pulmonary valve replacement and 11 had conduit replacement or augmentation. Three patients underwent tricuspid valve repair, 6 had Fontan, and 4 underwent a modified Maze procedure. Follow-up echocardiograms demonstrated a decrease in mean peak gradient to 4.3 mm Hg (range, 0 to 15 mm Hg), a change in mean peak gradient of 41.1 mm Hg (93% reduction). After stenting the mean pulmonary artery diameter increased to 10.9 mm (range, 6 to 17.9 mm). There was no perioperative mortality. At a mean follow-up of 22.8 months (range, 6 to 57 months), there were no surgical or percutaneous reinterventions.
Conclusions: Intraoperative pulmonary artery stenting is a safe and effective technique that can be used as an alternative to patch angioplasty. Close follow-up is needed to examine the long-term outcome of this procedure, with special attention to the growth and development of the stented vessel.
|
Introduction |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
Patch angioplasty of stenotic PAs has been a safe and effective technique. However, it can be a challenging surgical task and is not without intraoperative or long-term complications. Compression from surrounding structures, difficult intraoperative access owing to anatomic location, right ventricular hypertrophy, scarring and postoperative adhesions, excessive pulmonary blood flow from collaterals, and even sometimes the need to implement circulatory arrest or low-flow cardiopulmonary bypass are some factors that can make the operative repair lengthy and difficult. In addition, the need for further reintervention either surgically or percutaneously is always a possibility.
In an effort to decrease operative complexity and time we combined intraoperative endovascular PA stenting in adjunct to the surgical repair. The aim of this study was to review our initial experience using this surgical technique with special emphasis on the safety, feasibility, and complications related to the technique, as well as the need for further surgical or percutaneous intervention.
|
Patients and Methods |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
From our computerized database we identified 22 patients with congenital heart disease that met the criteria for analysis. Patients with pulmonary vein stenosis were excluded from the study. Echocardiograms, cardiac catheterization, clinical data, and operative reports were reviewed retrospectively. All procedures were performed at the University of California Los Angeles Medical Center. There were 12 males and 10 females. The mean age was 9.3 years (range, 9 months to 24 years).
Preoperative and postoperative PA size and peak pressure gradient across the stenosis were determined by two-dimensional and Doppler flow echocardiograms.
Congenital heart disease diagnoses were as follows: pulmonary atresia with ventricular septal defect in 5, pulmonary atresia with intact septum in 2, tetralogy of Fallot in 3, truncus arteriosus in 4, double-outlet right ventricle in 1, hypoplastic left heart syndrome in 1, transposition of the great arteries in 3, aortic valve insufficiency in 1, and complex congenital cardiac defects in 2 (Table 1).
|
Surgical Technique
All procedures were performed under hypothermic cardiopulmonary bypass. No patient required circulatory arrest.
The stent was selected on the basis of the preoperative information of the vessel diameter, the location of the stenosis, the underlying disease, and the perioperative anatomic findings. The main PA or conduit was first incised in a longitudinal fashion, and the branch PAs were visualized directly. Dissection was carried out only on the anterior aspect of the PA branch to be treated. The affected PA branch was dilated first with a Kelley clamp or Hegar dilator. The stent was placed under direct vision across the lesion by the operating surgeon, and while holding it in place the assistant surgeon inflated the balloon. The stent was inflated according to manufacturer’s guidelines. The proximal aspect of the stent was directly visualized, and the distal aspect was palpated digitally and was assured to stent the lesion as the stents after balloon inflation become foreshortened. An interventional pediatric cardiologist was present during the deployment. We avoided placing the stent across hilar PA branching points to avoid distortion of the anatomy of the segmental branches, vessel occlusion, or airway obstruction. We did not use a guidewire during stent placement (although in cases when the anatomy is not clear it can be used to define the distal end of the stent). Intraoperative fluoroscopy was used in only 1 patient early in our experience.
|
Results |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
One stent that was placed percutaneously was redilated in the operating room. One stent that was placed by the interventional cardiologist preoperatively and had migrated distally was removed and replaced with a new one. The majority of the stenoses were located in the proximal and middle of the branch PA. Concomitant cardiac procedures included 13 pulmonary valve replacements using bioprosthesis. There were 11 conduit augmentations or replacements. Patch angioplasty of the contralateral PA was performed in 11 patients. Three patients underwent tricuspid valve repair, 6 had Fontan completion (revision Fontan in 1, extracardiac conduit in 4, and lateral tunnel in 1), and a modified Maze procedure was performed in 4 patients.
Available echocardiograms in 20 patients revealed a mean preoperative diameter of 7.6 mm (range, 3 to 16.5 mm) and a mean peak preoperative pressure gradient of 45.4 mm Hg (range, 20 to 120 mm Hg). After stenting, the mean PA diameter increased to 10.9 mm (range, 6 to 17.9 mm). Recent follow-up echocardiograms demonstrated a decrease in the mean peak pressure gradient to 4.3 mm Hg (range, 0 to 15 mm Hg), which represents a change in the mean peak pressure gradient of 41.1 mm Hg (93% reduction).
There was no perioperative mortality no periprocedural morbidity and no airway compression. We had no stent migration or stented vessel thrombosis or perforation.
Postoperative complications were pneumothoraces in 2, pneumomediastinum in 1, chylothorax in 1, and supraventricular arrhythmia in 1 patient. These complications may not be related to the stenting itself, but we do report them. All patients were kept on aspirin to avoid stent thrombosis and the development of intimal hyperplasia. Patients with Fontan circulation were anticoagulated with sodium warfarin (Coumadin) for 6 to 12 months postoperatively.
All patients had significant symptomatic improvement. There were no late deaths. At a mean follow-up of 22.8 months (range, 6 to 57 months) there were no surgical or percutaneous reinterventions.
|
Comment |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
Despite the wide application of the percutaneous stenting of the PA, the experience with intraoperative stenting has been limited. Coles and colleagues [7] from the Toronto Sick Children’s Hospital reported their experience and suggested a word of caution. In their review of 11 cases they had 3 early deaths (27%) and a high incidence of intimal proliferation and stent obstruction in 5 of 7 surviving patients. A subsequent report from the same institution reported on 49 percutaneous stents and 6 intraoperative implantations and yielded more favorable outcomes [1]. In addition Mendelsohn and associates [8] from the University of Michigan reported on 10 patients who were treated with endovascular stents with no mortality. Ungeleider and coworkers [9] from the University of Oregon Health Sciences reported the largest series thus far with 31 procedures on 27 patients using intraoperative stenting. Overall, their experience with PA stenting has been favorable. They reported 5 in-hospital and 3 late deaths. At a mean follow-up of 2.3 years the mean instantaneous gradient fell from 66 to 28 mm Hg as measured by echocardiography (p = 0.01). Early in their experience they had 8 stent-related complications: laceration of the PA in 2, inadequate balloon dilatation in 1, malposition of the stent in 1, stent dislodgment in 2, and 1 patient who experienced reperfusion pulmonary edema [9].
Ungeleider and coworkers [9] also included 5 patients with pulmonary vein stenosis treated with intraoperative endovascular stenting. The outcome in these patients was unfavorable, with only 1 patient having a successful outcome. These data parallel the experience reported by others including data from the interventional literature [2, 10]. For these reasons we have not included patients with pulmonary vein obstructive lesions in our study. In addition, reviewing patients with one pathologic diagnosis makes the analysis more uniform.
In our series, we had no early or late deaths. In addition, we had no periprocedural morbidity defined as stent thrombosis or migration, or vessel perforation. We attribute this to careful patient selection and a detailed preoperative and intraoperative planning and procedure contact in close consultation with experienced interventional cardiologists in our institution.
Hjortal and associates [11] from the Great Ormond Street Hospital for Children in London have proposed the "hybrid" approach to complex congenital cardiac problems. They reported on 4 patients who underwent intraoperative PA stenting concomitant to surgical repair and 2 patients who underwent balloon occlusion of a Blalock-Taussig shunt or major aortopulmonary collateral to control pulmonary blood flow during surgical repair.
These studies are excellent examples demonstrating that close collaboration between interventional cardiology and cardiac surgery facilitates better outcomes in patients with complex congenital cardiac problems. In addition, mastering catheter-based techniques adds to the armamentarium of the cardiac surgeon.
Data analysis indicates that intraoperative PA stenting is an effective technique to treat PA stenosis. Our echocardiographic findings demonstrated a mean increase of the stented vessel diameter by 3.3 mm and a decrease of the mean peak pressure gradient of 41.1 mm Hg, a 93% reduction (Figs 1–3).
|
|
|
Patch angioplasty can be a challenging procedure because access to the right PA behind the aorta or the left PA toward the lung hilum in conjunction with excessive pulmonary blood flow from collaterals may require the implementation of low-flow cardiopulmonary bypass or even circulatory arrest with the possibility of hypotensive cerebral damage [11]. Patch material for PA reconstruction includes autologous pericardium, bovine pericardium, Gore-Tex, and homograft. We have favored autologous pericardium, which often is not available secondary to prior use. Irrespective of the material used, there is always the possibility of external compression from surrounding structures. The endovascular stents provide a structural framework that minimizes that. Endovascular stenting might be of particular value in small-caliber PAs (2 to 4 mm) in which patch augmentation has a more limited result.
We recommend the use of reexpandable stents that can undergo repeat dilatation (percutaneously) if needed in the future to accompany the growth of the patient.
Potential disadvantages include the following. There are issues with growth and development of the stented vessel. It is a legitimate concern, and close long-term follow-up is needed to address this question. Reports of repeat dilatation of stented PAs are available in the interventional cardiology literature [3, 9]. The possibility for stent thrombosis is always an issue whenever a foreign body is introduced into the vascular system, irrespective of the mode of placement (percutaneous or surgical). The current approach has been to use antiplatelet therapy for prevention of thrombosis and the development of intimal hyperplasia.
Vessel perforation and hemorrhage can be a serious complication. To prevent this, circumferential dissection of the vessel must be avoided, leaving the posterior wall attached to the surrounding structures for stronger external support. In addition overinflation of the balloon or stent beyond set manufacturer limits must be avoided to prevent airway compression. Use of a low-profile stent with less-sharp edges decreases the possibility of complications.
Decreasing the incidence of segmental branch PA obstruction requires avoiding placement of stents across branching points, as determined by manual measurement or measurement of the distance using a guidewire. If there is concern about the distal position of the stent, intraoperative fluoroscopy can be used for more accurate placement. Although we have not reoperated on any of these patients by now, our experience with operating on a few patients who had percutaneous stent placement has shown that it is possible to incise across the stent and suture a patch over it. Stent migration can be avoided by careful intraoperative placement across the stenotic lesion, secure positioning, and the addition of transfixing stitches through the stent and the vessel wall.
In conclusion, intraoperative PA stenting is a safe and effective technique that can be used as an alternative to patch angioplasty with excellent results, particularly when the branch PA is relatively inaccessible. Close follow-up is needed to examine the long-term outcome of this procedure, with special attention to the growth and development of the stented PA.
|
Discussion |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
The reason I ask is that sometimes with the open technique you cannot see the distal point of the stent. You just simply do not see how far you are inserting it, and then when you deploy it, you very well could tear the lobar branches’ takeoff. What is your technique for that?
DR MITROPOULOS: We made an estimation of the length of the RPA (right pulmonary artery) based on the preoperative data, the cardiac catheterization, or the echocardiogram, and by intraoperative visualization. So far the longest stent we have deployed was 2.7 cm. So for the most part we try to stay away from the branch points.
One other technique that we have not used, but you could use, especially for the RPA or the left PA, is put the guidewire until it hits the wall of the vessel, retract that slightly, so that you are in the main vessel, and then put the stent and the balloon through the guide ire.
DR BACHA: But, if I may, you are still working blindly at that point. You do not know where the tip of the guidewire is exactly.
DR MITROPOULOS: But you can still feel the distal aspect of the stent by finger when you place it.
DR BACHA: That is not necessarily true. I mean one better way, if I may share it, is to open the chest, and dissect the things you need to dissect without dissecting the area to be stented. Before going on bypass, put a pursestring on the PA and shoot an angiogram under fluoroscopy and then put your stent in, on a beating heart, with fluoroscopic control, based on the angiogram that you just shot. It is a very nice controlled way and very safe because you see exactly how far distally you need to go with the stent.
DR JOSEPH J. AMATO (Chicago, IL): Similar to Dr Bacha’s questioning, I am concerned about the use of stents, especially the uncovered stents. And I do not know whether I share Dr Bacha’s beating-heart situation, because I do know of one case where, with a beating heart, the pulmonary artery was torn and air got sucked into the heart. So I am just wondering whether, first of all, you have not had an experience of a torn pulmonary artery nor have you had any hemorrhage; is that correct?
DR MITROPOULOS: Since the time of the submission of the abstract, 1 patient with pulmonary atresia, who has not been included in the study, had a problem with intraoperative pulmonary artery perforation and bleeding after the stent deployment.
DR AMATO: How would you then prevent that in the future?
DR MITROPOULOS: Well, that is a very good point. One of the things that you need to be very careful is not to do circumferential dissection of those vessels so that at least posteriorly, superiorly, and inferiorly you have a more solid surrounding environment. Especially the posterior wall, which is the hardest to repair. The anterior wall is easier to repair.
One other thing that you need to be very careful with, especially when you go into the hilum, is not to go too distally. In those cases, as you said, the use of intraoperative fluoroscopy might be one way to do it. One important point is not to exceed the manufacturer guidelines as to how much you would inflate the balloon and overstretch the stent to achieve greater diameter of the pulmonary artery.
DR AMATO: I would just add a word of caution that I think if I were doing the stenting that I do not think I would do it on a beating heart, at least at that point; at the time of inflation, I would stop the motion of the heart just temporarily so as not to cause any error.
DR MITROPOULOS: We agree and we have been deploying stents while the heart has been arrested.
|
References |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
