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J Thorac Cardiovasc Surg 2007;134:1413-1420
© 2007 The American Association for Thoracic Surgery
Surgery for Congenital Heart Disease |
Alder Hey Children Hospital, Liverpool, England.
Read at the Eighty-seventh Annual Meeting of The American Association for Thoracic Surgery, Washington, DC, May 5-9, 2007.
Received for publication February 9, 2007; revisions received March 15, 2007; accepted for publication March 22, 2007. * Address for reprints: Antonio F. Corno, MD, FRCS, FACC, FETCS, Cardiac Surgery, Alder Hey Children Hospital, Eaton Road, Liverpool, L12 2AP, United Kingdom. (Email: Antonio.Corno{at}rlc.nhs.uk).
| Abstract |
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Methods: Forty consecutive infants underwent conventional pulmonary artery banding (n = 20; mean age, 1.8 ± 1.5 months; mean weight, 3.7 ± 0.7 kg) or FloWatch pulmonary artery banding (n = 20; mean age, 2.6 ± 1.3 months; mean weight, 4.1 ± 0.8 kg). Indications were preparation for biventricular repair in 16 of 20 infants, univentricular repair in 2 of 20 infants, and left ventricular retraining in 2 of 20 infants in the conventional pulmonary artery banding group versus 13 of 20, 5 of 20, and 2 of 20 infants, respectively, in the FloWatch pulmonary artery banding group. Twelve of 20 infants required preoperative mechanical ventilation in the conventional pulmonary artery banding group (mean duration, 3.3 ± 4.3 days) versus preoperative mechanical ventilation required by 14 of 20 in the FloWatch pulmonary artery banding group (mean duration, 17.5 ± 19.0 days; P < .005).
Results: There were 3 early and 2 late deaths after conventional pulmonary artery banding (mean follow-up, 10.8 ± 9.6 months; range, 1–33 months) versus no early and 2 late deaths after FloWatch pulmonary artery banding (mean follow-up, 13.4 ± 10.4 months; range, 1–38 months). Postoperative mechanical ventilation and intensive care unit and hospital stays were significantly longer after conventional pulmonary artery banding than those after FloWatch pulmonary artery banding, respectively (10.4 ± 11.2 vs 3.0 ± 3.1 days [P < .01], 20.3 ± 19.9 vs 5.3 ± 4.6 days [P < .005], and 45.6 ± 41.6 vs 15.4 ± 6.4 days [P < .005]). Reoperation to adjust the band was required in 7 (35%) of 20 infants after conventional pulmonary artery banding, whereas no reoperations were required after FloWatch pulmonary artery banding (P < .005). Average cost of stay in the intensive care unit and hospital was, respectively, $45,000 and $45,300 cheaper with FloWatch pulmonary artery banding than average cost with conventional pulmonary artery banding, largely surpassing the cost of the device ($10,000).
Conclusions: FloWatch pulmonary artery banding appears superior to conventional pulmonary artery banding because (1) reoperations are not required; (2) postoperative management is simplified and postoperative mechanical ventilation, stay in the intensive care unit, and stay in the hospital are significantly reduced; and (3) the reduction in costs of postoperative mechanical ventilation, stay in the intensive care unit, and stay in the hospital significantly outweigh the cost of the device.
| Introduction |
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Improvements in the perioperative management of patients with congenital heart defects have made the surgical repair of most of the intracardiac defects a clinical possibility, with good outcomes even in small infants.1
Palliation with pulmonary artery banding (PAB) is nowadays rarely considered for simple congenital heart defects, such as isolated ventricular septal defects. Recent clinical reports have considered the PAB for malformations, such as multiple ventricular septal defects,2
ventricular septal defects associated with aortic arch interruption,2,3
complete atrioventricular septal defects,2,4-7
functionally univentricular hearts,2,5,6,8-10
left ventricular retraining in transposition of the great arteries with late referral,11
and congenitally corrected transposition of the great arteries.12-14
Other indications for PAB include hypoplastic left heart malformations, either as a rescue procedure in critically ill neonates or as an elective preparation for the subsequent operation (ie, either the Norwood procedure to a univentricular repair or heart transplantation).15-18
After long-term experimental evaluation in animals,19
a telemetrically controlled adjustable PAB device, the FloWatch PAB device (EndoArt, Lausanne, Switzerland), has been successfully introduced in clinical practice in different institutions after positive results were obtained in a multicenter clinical trial.20-22
This new implantable, wireless, battery-free device demonstrated the feasibility of repeated progressive occlusions and reopenings of the device to the desired percentage of occlusion through a remote control unit.
The FloWatch PAB device comprises an implantable device (Figure 1) and an external control unit. With the device in the clipped position, the dimensions are as follows: 26 mm (length) x 18 mm (width) x 18 mm (height). The change in the adjustable area is obtained by means of a piston driven by an incorporated electrical micromotor. The adjustment is done through the external control unit, delivering the energy to the implanted device through an antenna, as well as the commands to drive the microengine. The telemetric system is designed such that the implant sends back to the control unit information about its functioning. Thus the FloWatch PAB device allows easy and repetitive adjustable PAB, avoiding the need for reoperation or any invasive procedure to adjust the band in both ways.19-22
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In infants with functionally univentricular hearts, the device makes possible repetitive titration of pulmonary artery pressures distal to the narrowing to reach the desired low values and later perform a staged cavopulmonary connection. In patients in whom left ventricular retraining is required because of late referral in the presence of transposition of the great arteries and in congenitally corrected transposition of the great arteries (ie, double discordance), FloWatch PAB is the only technique that allows modifications of the distal pulmonary artery pressure in a fashion suitable with the continuously variable clinical needs of these conditions, generally requiring repeated adjustments and prolonged stay in the intensive care unit (ICU).11,13,23
On the contrary, FloWatch PAB has never been used for bilateral banding in hypoplastic left heart syndrome because its size precludes the use of 2 devices, one on each branch of the pulmonary artery.
The clinical experience with this device confirmed in all the above situations a substantial reduction of mortality and morbidity associated with conventional surgical banding in addition to a significant reduction in ICU and hospital stay.20-22
Finally, another important advantage of FloWatch PAB is that at the moment of subsequent intracardiac repair and debanding, consisting of unclipping and removal of the device, surgical reconstruction of the pulmonary artery is no longer required.24,25
FloWatch PAB obtains the same reduction of cross-sectional area as does conventional circular banding and therefore the same pressure gradient, without any reduction of the perimeter of the pulmonary artery, as in conventional banding. By maintaining an intact circumference, with the possibility of growth, the wall of the pulmonary artery can maintain intact its anatomic properties, without any reduction in elasticity. The simple device removal at the time of intracardiac repair is enough to obtain spontaneous and complete expansion of the wall of the pulmonary artery, with maintenance of its elasticity and pliability.25
Despite the proved clinical advantages, the main criticism from colleagues, hospital administrators, and insurance companies relates to the price of the device ($10,000) when compared with a conventional band.
This prospective study, approved by the institutional ethical committee, has been designed to compare the results obtained with conventional pulmonary artery banding (conv-PAB) with those obtained with FloWatch PAB (FW-PAB) in 2 homogeneous groups of infants undergoing PAB in the same period and the costs related to each treatment strategy.
| Materials and Methods |
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The only statistically significant difference (P < .005) between the 2 groups was mean duration of preoperative mechanical ventilation, which was 3.3 ± 4.3 days (range, 0–15 days) in the conv-PAB group and 17.5 ± 19.0 days (range, 0–60 days) in the FW-PAB group (Table 1).
The assignment of infants to one or the other group has been dictated by the availability of the device. The availability was determined by the initial cost of the FW-PAB device ($10,000). Because of the budgetary constraints within our institution, the device was only intermittently available for clinical use. When there were more infant candidates for PAB than devices available, the FW-PAB device was, in general, reserved for the infants more likely to have difficult postoperative management, such as patients with prolonged preoperative mechanical ventilation, patients in preparation for a univentricular type of repair, or both. The final decision was always a joint agreement reached during our weekly departmental case discussion meeting. All patients were operated on by one of the 2 surgeons (AFC and MP) and managed during the entire perioperative period by the same team, according to the same clinical protocols.
In both groups the PAB was performed through a median sternotomy. Conv-PAB was accomplished with a 4-mm Teflon band, premeasured with the Trusler rule, and adjusted intraoperatively according to the measured distal pulmonary artery pressure and systemic oxygen saturation. Implantation of the FW-PAB was performed by using the same surgical approach for the conv-PAB, with simple clipping of the device around the pulmonary artery and without intraoperative measurement of the distal pulmonary artery pressures but with telemetric adjustments of the device, guided by means of Doppler echocardiography, after transfer of the patient to the ICU.
The 2 groups have been compared by collecting the following data: (1) early and late deaths; (2) duration of postoperative mechanical ventilation and length of stay in the ICU and hospital; (3) need for any PAB-related reoperations to tighten, release, or both the conv-PAB versus need for telemetric adjustments of the FW-PAB to either narrow the device, release the device, or both; and (4) costs of the mean stay in the ICU ($3000 per patient per day) and in the hospital ($1500 per patient per day) and costs for reoperations ($6500 for 1 off-bypass operation).
The end points of this prospective study were as follows: (1) death; (2) debanding (or removal of the device) during the intracardiac repair; and (3) the end of January 2007 for all the remaining patients waiting for intracardiac repair.
The paired Student t test was used for comparisons between the 2 groups.
| Results |
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During the follow-up period, 19 patients underwent intracardiac repair and pulmonary artery debanding, 12 in the conv-PAB group and 7 in the FW-PAB group. None of these 19 patients died. Ten of the 12 patients with conv-PAB required surgical enlargement of the main pulmonary artery, with a patch of heterologous pericardium to relieve residual stenosis after band removal. No reconstructive procedure of the pulmonary artery was required in all patients of the FW-PAB group because complete expansion of the pulmonary artery to its normal size followed removal of the device (P < .0005).
At the end of the period of observation, 3 patients in the conv-PAB group and 12 patients in the FW-PAB group were waiting for intracardiac repair.
With regard to the cost calculation (Figure 2), only considering the average cost per patient of ICU ($60,900 in the conv-PAB group and $15,900 in the FW-PAB group) and hospital ($68,400 in the conv-PAB group and $23,100 in the FW-PAB group) stay and the average cost of reoperation ($2275) to adjust the conv-PAB, the average cost per patient was $92,575 cheaper with FW-PAB than with conv-PAB, largely surpassing the cost of the device ($10,000).
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| Discussion |
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The telemetrically adjustable PAB, which is now available with the FW-PAB device, an implantable, wireless, and battery-free device, gives the clinician the ability to repeatedly progressively narrow and reopen the pulmonary artery to a desired percentage of occlusion. Positive results have now been obtained in a number of different institutions.20-22
This device provides an adjustable PAB by means of remote control, avoiding any PAB-related reoperation or other invasive procedure to adjust the band either way, tightening or releasing.19-22
The availability of this surgical armamentarium allows an easier management of complex infants20-22
and also avoids the pulmonary artery reconstruction when intracardiac repair is undertaken.24,25
The main criticism of FW-PAB from colleagues, hospital administrators, and insurance companies has always been its price ($10,000) when compared with that of the conventional band.
Our study of 2 homogeneous groups of patients undergoing conv-PAB or FW-PAB in the same period of time not only confirms the clinical advantages of FW-PAB over conv-PAB with a significantly shorter and less complicated postoperative course but also demonstrates the substantial reduction of costs with the FW-PAB, greatly outweighing the initial cost of the device.
| Limits of the Study |
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None of the clinicians involved in caring for the patients in the perioperative period were blinded with respect to the type of PAB used. In our opinion, it was important to provide this information in case of urgent need for PAB adjustment, either with chest reopening for conv-PAB or with the remote control for FW-PAB.
With regard to the cost calculation, only the costs of ICU and hospital stay and reoperations have been taken into account. The inclusion of additional costs, such as costs for the treatment of complications because of a longer stay in the ICU and hospital and costs for the pulmonary artery repair, at the time of the intracardiac repair would have further increased the difference between the conv-PAB and FW-PAB groups in favor of FW-PAB.
| Conclusions |
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| Acknowledgments |
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| Footnotes |
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| References |
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