Ann Thorac Surg 2008;85:1787-1788. doi:10.1016/j.athoracsur.2007.11.007
© 2008 The Society of Thoracic Surgeons
Case Reports
Delayed Improvement in Valve Hemodynamic Performance After Percutaneous Pulmonary Valve Implantation
Josep Rodés-Cabau, MDa,*,
Christine Houde, MDb,
Jean Perron, MDa,
Lee N. Benson, MDc,
Philippe Pibarot, DVM, PhDa
a Québec Heart Institute–Laval Hospital, Québec City, Québec, Canada
b Centre Hospitalier Universitaire Laval, Québec City, Québec, Canada
c Hospital for Sick Children, Toronto, Ontario, Canada
Accepted for publication November 5, 2007.
* Address correspondence to Dr Rodés-Cabau, Québec Heart Institute–Laval Hospital 2725, Chemin Ste-Foy, G1V 4G5, Quebec City, Canada (Email: josep.rodes{at}crhl.ulaval.ca).
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Abstract
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We report the case of a 21-year-old woman with a severely stenotic pulmonary homograft who underwent percutaneous pulmonary valve implantation, with no significant change in transvalvular gradient within the 24 hours after the procedure. Major improvement in hemodynamic valve performance of more than 60% decrease in transvalvular gradient and more than 30% increase in pulmonary valve area was observed 3 months after the procedure, showing that hemodynamic improvement can occur late after pulmonary valve implantation. An echocardiogram after 3 months should be done before concluding the procedure failed and that reintervention is necessary.
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Introduction
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Percutaneous pulmonary valve implantation (PVI) has been recently proposed as an alternative to surgical repair for the treatment of diseased right ventricle-to-pulmonary artery conduits [1]. Pulmonary valve implantation generally leads to an immediate and significant improvement of transvalvular gradient in most patients with predominantly stenotic conduits [2]. The present case demonstrates that hemodynamic improvement can occur late after PVI implantation.
A 21-year-old woman with a history of bicuspid aortic valve leading to severe aortic stenosis and insufficiency underwent a Ross procedure at the age of 10 years, with implantation of a 22-mm homograft in the pulmonary position. She presented with exertional dyspnea 11 years after this operation, and the chest roentgenogram showed the presence of significant calcification at the level of the pulmonary homograft. A Doppler echocardiographic examination revealed a peak gradient of 75 mm Hg and mean gradient of 46 mm Hg across the pulmonary homograft, a pulmonary valve effective orifice area of 0.65 cm2, and moderate pulmonary insufficiency. The patient underwent maximum exercise stress test. The peak workload was 150 W, and oxygen consumption was 32 mL/kg/min. The transvalvular gradients increased markedly during exercise (peak, 110 mm Hg; mean, 74 mm Hg). The decision was made to implant a percutaneous pulmonary valve, and written informed consent was obtained from the patient.
The procedure was performed by femoral approach, under general anesthesia. Right systolic ventricular pressure was 60 mm Hg, with a peak systolic gradient across the pulmonary homograft of 42 mm Hg. Angiography performed at the level of the pulmonary homograft allowed the calculation of a minimal lumen diameter of 16 mm at the mid portion of the homograft.
A Melody valve (Medtronic, Minneapolis, MN), which consists of a bovine jugular valve sutured within a platinum-iridium stent, was mounted in a 22-mm balloon delivery system and inserted through an extra-stiff guidewire up to the pulmonary homograft. After valve implantation, balloon dilation was performed with a 20-mm Mullins high-pressure balloon (Numed Canada Inc, Cornwall, Ontario, Canada).
At the end of the procedure, the right systolic ventricular pressure was 56 mm Hg, and the peak transvalvular gradient was 39 mm Hg. Pulmonary angiography showed the absence of pulmonary regurgitation (Fig 1). The day after the procedure, Doppler echocardiography showed no improvement in the peak transvalvular gradient (75 mm Hg) and only slight improvement in the mean transvalvular gradient (37 mm Hg) compared with values before the procedure. There was, nonetheless, a moderate improvement in valve effective orifice area (0.96 cm2). No right ventricular outflow tract obstruction was observed at anytime. A chest roentgenogram showed the correct position of the valve in the pulmonary homograft and the absence of any stent fracture.
The possibility of immediate reintervention (surgical homograft replacement or homograft stent implantation) was considered, but after a meeting with the physician responsible for the patient and the interventional team, it was decided that close clinical follow-up rather than immediate reintervention would be undertaken.
In the weeks after intervention, the patient reported a progressive improvement of symptoms and was completely asymptomatic at the 3-month follow-up. At that time, the chest roentgenogram showed the correct position of the valve, the absence of any stent fracture, and no significant change in stent diameters compared with those obtained 24 hours after the procedure. Doppler echocardiography revealed significant improvement in the transvalvular gradient (peak, 26 mm Hg; mean, 16 mm Hg), further improvement in the effective orifice area (1.27 cm2), and the absence of pulmonary regurgitation. Serial changes in pulmonary valve hemodynamics after PVI are summarized in Table 1. During stress echocardiography, the transvalvular gradient increased up to 69/45 mm Hg, and the effective orifice area increased to 1.43 cm2. Peak exercise workload was 180 W, and oxygen consumption was 37 mL/kg/min.
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Table 1 Pulmonary Valve Hemodynamic Changes After Percutaneous Pulmonary Valve Implantation Determined by Doppler Echocardiography
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Comment
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Several studies have reported that the hemodynamic performance of stentless bioprosthetic valves may improve progressively during the 3 to 6 months after aortic valve replacement [3, 4]. A reduction in gradient of up to 30% and an increase in effective orifice of about 5% to 10% have been observed between the predischarge and the late postoperative measurements.
The present report demonstrates that progressive improvement in valve hemodynamic performance may also occur after percutaneous implantation of a pulmonary bioprosthesis, and that the magnitude of such improvement may be much higher than what was reported in previous studies on aortic stentless bioprostheses [3, 4]. In this patient, implantation of a tissue valve was associated with minimal hemodynamic improvement immediately after its implantation, but a dramatic reduction of transvalvular gradients (>60%) and an increase in effective orifice area (>30%) was noted within 3 months after the intervention.
The occurrence of perivalvular edema/hematoma and inflammation after valve implantation and its progressive postoperative regression [4], as well as the long-term exposure to pulsatile transvalvular flow and intraluminal radial forces, may have contributed to the optimization of the three-dimensional configuration of the valve and to the improvement in the valve-opening kinetics. These mechanisms may contribute to explain the time-related hemodynamic changes observed in the present case.
Percutaneous PVI is an evolving technology that will probably undergo significant expansion in the next few years. The information provided by the present report might have important clinical implications with regard to this procedure. Given that major hemodynamic improvement can occur within the next few months after PVI, one should repeat the echocardiographic examination at 3 months before concluding that the procedure failed and considering reintervention. Also, effective orifice area rather than transvalvular gradient might be a better index to determine the hemodynamic performance of the valve after PVI in patients with predominantly stenotic lesions. Larger series are needed to evaluate the exact incidence of this phenomenon and further explore the potential mechanisms responsible for this delayed improvement in valve hemodynamic performance.
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References
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- Khambadkone S, Bonhoeffer P. Nonsurgical pulmonary valve replacement: why, when, and how? Catheter Cardiovasc Interv 2004;62:401-408.[Medline]
- Coats L, Khambadkone S, Derrick G, et al. Physiological and clinical consequences of relief of right ventricular outflow tract obstruction late after repair of congenital heart defects Circulation 2006;113:2037-2044.[Abstract/Free Full Text]
- Dumesnil JG, LeBlanc MH, Cartier PC, et al. Hemodynamic features of the freestyle aortic bioprosthesis compared with stented bioprosthesis Ann Thorac Surg 1998;66:S130-S133.[Medline]
- Bortolotti U, Scioti G, Milano A, Borzoni G, Nardi C, Tartarini G. The Edwards Prima stentless valve: hemodynamic performance at one year Ann Thorac Surg 1999;68:2147-2151.[Abstract/Free Full Text]
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Abstract
Introduction
