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a Cardiac Unit, Great Ormond Street Hospital for Children, NHS Trust, Great Ormond Street, WC1N 3JH London, United Kingdom
b Policlinico San Donato Milanese IRCCS, Milan, Italy
Received 25 September 2007; received in revised form 11 December 2007; accepted 20 December 2007.
* Corresponding author. Tel.: +44 20 74059200; fax: +44 20 74301281. (Email: tsangv{at}gosh.nhs.uk).
| Abstract |
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Key Words: Percutaneous Pulmonary valve Implantation Emergency surgery
| 1. Introduction |
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| 2. Patients and methods |
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Current indications for PPVI are RVOT conduits with diameter between 16 and 22 mm, age >5 years and weight >20 kg.
Current limitations for PPVI are RVOT dimensions over 22 mm with dynamic outflow aneurysms. Retrosternal conduits with extrinsic compression will have incomplete relief of stenosis [7]. In patients with conduits less than 16 mm a temporary relief of RVOT gradient may be achieved, however eventually these patients would need a larger effective diameter of the RVOT.
Between 09/2000 and 01/2007, 152 patients (pts) received a percutaneous pulmonary valve at Great Ormond Street Hospital for Children and The Heart hospital in London and at the Hospital Necker in Paris. Six out of 152 (3.9%) pts had to undergo ERS after a major complication during implantation of the percutaneous valve. Patient's charts were analysed in retrospect. Their preoperative characteristics are summarised in Table 1 .
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2.3 Case history 3
A 37-year-old female patient with a diagnosis of congenital pulmonary stenosis, had an open pulmonary valvotomy at the age of 5 years followed by homograft implantation at the age of 32 years. The indication for PPV was significant regurgitation of the previously implanted homograft. The procedure was uneventful and a size 22 mm valve was implanted but the patient became unwell approximately 4 h after the procedure with signs of low cardiac output. Chest X-ray demonstrated tilting of the valve (Fig. 2
) with echocardiographic and clinical signs of severe right ventricular outflow tract obstruction. Adrenaline boluses were required to sustain cardiac output prior to transfer to the operating theatre. The right atrial pressure was measured at 40 mmHg shortly before cardiopulmonary bypass. At surgery, the percutaneous valve was replaced with a Hancock® conduit.
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Before implantation, she had moderate stenosis and regurgitation with half systemic RV pressures. An 18 mm system was implanted, but an angiogram demonstrated no flow into the right pulmonary artery. Patient was transferred to the operating theatre with stable haemodynamics for explantation of the device and implantation of a pulmonary homograft.
2.5 Case history 5
A 9-year-old female patient with dextrocardia, congenitally corrected transposition (CCTGA), double outlet right ventricle (DORV), pulmonary stenosis, VSD. She had a Mustard procedure with VSD closure and homograft from the right ventricle to pulmonary artery at the age of 2 years. An 18 mm stent was later placed due to homograft stenosis at the age of 4.
After deployment of an 18 mm percutaneous valve there was sudden LV failure. External cardiac massage was started. An aortic root injection demonstrated initially no flow into the LCA. After 25 min of cardiac massage, the stent became compressed and flow to the LCA was restored (Fig. 3 ). She was transferred directly into the operating theatre. The percutaneous valve was replaced with a size 22 mm pulmonary homograft.
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A 20 mm device was chosen and deployed successfully. Shortly after implantation, her blood pressure started to drop. Repeat screening revealed a large right haemothorax. Drains were placed and in total 1900 ml blood was auto-transfused. She was transferred directly to the operating theatre for exploration. The valved stent was left in situ and the area of the junction between the right and main pulmonary artery reinforced with plicating sutures.
| 3. Results |
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The percutaneous valve was explanted in five patients and was replaced with aortic or pulmonary homograft in three patients with standard technical principles of pulmonary valve replacement applied [1]. Two patients received a valved conduit (Hancock®, Medtronic Ltd.). In one patient, a contained defect in the homograft was presumed at the distal end of the homograft at the junction to the right pulmonary artery. This area was repaired with plicating sutures and the valve was left in situ.
Early outcome: All patients survived. One patient (patient 1) sustained a neurological insult consisting of bulbar weakness with speech difficulty and temporary upper limb weakness. On EEG, there were no signs of focal seizure activity and on MRI no gross abnormality could be revealed. The mean intensive care unit stay was 5.5 ± 3.2 days.
Follow-up: Follow-up was complete in all patients with a mean of 25.2 ± 17.1 months.
On echocardiography, all patients have competent pulmonary valves with a velocity of 2.3 ± 0.4 m/s (mean value). Patient 3 is on antiarrhythmic medication at follow-up after 3 years due to atrial fibrillation/flutter and is scheduled to have radio frequency ablation. One patient (patient 1) has mild neurological impairment with learning difficulties.
| 4. Discussion |
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Mechanisms of acute PPVI failure: Upon reviewing the catheter implantation data, three different mechanisms of PPVI failure became apparent.
Firstly, there was dislodgement into a dilated right ventricular outflow tract in two of the patients. Another patient had a stent displaced into the distal pulmonary artery, which caused complete obstruction of the right pulmonary artery. With increasing experience in implanting percutaneous valve, patient selection and positioning of the device the incidence of this complication is likely to become less prevalent. Better understanding of complex geometry of the right ventricular outflow tract and its dynamics may also help to eliminate this complication mode [9].
Secondly, one patient suffered a compression of the LCA and as a result acute left heart failure. In retrospect, it became apparent that the previously implanted stent in the patient's homograft had not been brought to its full dimension of 18 mm.
Currently, all patients undergoing implantation have an aortic root injection to delineate coronary anatomy and its relationship to the right outflow tract.
Thirdly, the last complication encountered in our cohort was a ruptured homograft with resulting massive haemorrhage. PPVI relies on a strong platform to anchor the stented valve, which is mostly provided by a calcified homograft placed at previous surgery. There is inevitable interfering with the integrity of the homograft in all stenosed conduits upon implantation, but this is contained by the stent or surrounding fibrous tissue. In our opinion, factors such as unusual angles in the outflow tract, use of bicuspidised homografts are prone to homograft rupture and haemorrhagic complication. With increasing experience and contrary to our previous belief, the presence of a heavily calcified homograft is not a risk factor for rupture.
Management of acute PPVI failure: Three of the patients described had a potentially life-threatening complication. Upon reviewing, the anaesthetic protocols and operation notes important patterns of management of the complications encountered emerged.
Blood products have to be cross-matched and readily available for emergent perusal. Auto-transfusion played an important role in management of two patients with haemorrhagic complications. It is imperative to establish a reasonable safety margin/platform before urgent transfer to the operating theatre.
Operations on failed percutaneous valve implantations require a highly skilled surgical team and can pose significant technical difficulties. Almost all patients would have had multiple previous operations. The access to groin vessel cannulation can be hindered by previous catheterisations or implantation device in situ. Furthermore, the choice of a pulmonary valve substitute with known limitations of homograft availability on an emergency basis can be problematic. Biological valves or heterografts are often the only option.
Multidisciplinary approach to decision making: So far surgical replacement of pulmonary valve represents the gold standard in majority of paediatric cardiac centres. Surgical pulmonary valve replacement in our institution is reserved for pts with dilated outflow tracts that may also require additional procedures [1]. The surgery for right ventricular outflow tract reconstruction and the morbidity associated with repeated sternotomies is well described [10]. Risk of cardiac laceration at repeated sternotomy has been reported to be around 5% [11]. Limitations of the surgical approach are the durability and availability of an ideal pulmonary valve substitute. However, the issue of durability of pulmonary valve substitute also applies to the percutaneous valve. It is a bovine jugular valve and there is no reason why it should not be susceptible to valve degeneration and calcification [7]. PPVI is now limited to conduit stenosis and/or regurgitation. Current research on right ventricular outflow tract reducer is likely to extend the indications of this procedure to higher proportion of patients who underwent previous repair of tetralogy of Fallot and conditions where a competent pulmonary valve is required [12,13].
Review of outcome in interventional procedures such as percutaneous atrial septal defect closure and percutaneous aortic valve placement demonstrates that the surgical community should be prepared and take an active part in hybrid and transcatheter procedures [14,15]. To provide the best care for each individual patient, we must free ourselves from preconceived ideas, accept facts, integrate novelty and built a team concept, whilst sharing experience and expertise across the artificial boundaries of disciplines [16].
| 5. Summary |
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| Appendix A |
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Dr C. Schreiber (Munich, Germany): I think, very importantly, when I read your paper, and you stressed it in your last slide, you are using this technology at your institution now with a very high rate of success. Many of these complications happen in the early phase. The company is currently selling the valve very cautiously to be used in selected patients and teaches interventionalists or surgeons to use this new technology in an as safe as possible way. We know from CoreValve and Edwards and their preliminary results on interventional aortic valve replacement that they act likewise. I think you clearly made a point, and the message comes across in the paper, that any new technologies must be used with care and that a team approach is warranted. Maybe you could elucidate once again to the audience, because I think that is crucial, what it actually took to reoperate? You were a bit casual when you mentioned you took only around 30 min on average to open them up. Maybe you can share with us how difficult it was actually or what your tricks were to reopen these patients who often had multiple previous surgeries. This would then be our take home message.
Dr Kostolny: As you mentioned, in terms of patient selection, there is always a multidisciplinary approach to this. As you correctly pointed out operations in those patients can pose significant technical difficulties. All of them will have at least one previous operation. Surgical approach can be also a problem since the femoral vessels can be blocked from previous catheterisations or the delivery system of the device itself can be still in situ. Thirdly, availability of homografts on an emergency basis can be a problem and, as you have seen, we used heterografts in two of our patients. I would like to stress that it's very important to stabilize the patient. Therefore, resuscitation of the patient in the cath lab is very important before moving on and operating on them.
Dr A. Corno (Liverpool, United Kingdom): I have a very quick question. Can you please define exactly what do you mean by surgical backup? Is it a consultant surgeon available in the hospital or a free theatre to be readily available or a cardiopulmonary bypass machine with priming available? What is the level of surgical standby you require for this procedure?
Dr Kostolny: The first thing you mentioned, Im going to expand on that. Initially in our experience, there was a surgical backup with a cardiac theatre booked if you had a percutaneous pulmonary valve explantation, but what we learned, and I hope I was able to demonstrate that, you have to stabilize the patient before moving on and operating on them. There is nevertheless always a consultant surgeon in hospital during valve implantation and the theatre is not booked.
Dr W. Ruschewski (Goettingen, Germany): What's the reason that you use Hancock® valves and not Contegras? It's the same as your Melody.
Dr Kostolny: Personally, I think that they are prone to dilation and it is not my preference to use Contegras. I would rather use a heterograft.
Dr J. Comas (Madrid, Spain): I have only a curiosity. What is the psychologic direction of your cardiologists in these situations?
Dr Kostolny: Although it's the work of a cardiologist, the decision to implant a percutaneous valve is made by a team, and as a team, we have to select the patients, but we also have to deal with the complications together.
| Footnotes |
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Presented at the 21st Annual Meeting of the European Association for Cardio-thoracic Surgery, Geneva, Switzerland, September 16–19, 2007.

Disclosure: Dr Bonhoeffer is a consultant to Medtronic.
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