Case report
Autologous pericardium as patch material in the high pressure-system – report of a case of subsequent development of an aneurysm and review of the literature

Introduction
The operative strategy of elimination of tissue defects or the correction of complex congenital malformations is various [1-5]. Within such procedures autologous material is frequently used, e.g. autologous pericardium in the form of a patch. Mostly in the long-term follow-up of those patients the development of an aneurysm can be observed in the area of the patch [6]. The risk of a rupture in this area is at least the same as it is in presence of an aneurysm verum [7].
Case report
We report on a 46-year-old female patient, who already had undergone open blasting of the aortic valve in 1967 due to valvular stenosis. Nine years later prosthetic valve replacement was required because of the recurrence of both valvular and subvalvular stenosis. For the implantation of a Björk-Shiley© prosthesis the right coronary cusp had to be separated from the acoronary one and the aortic valve ring, which was extremely tight, had to be incisioned. After the incision in this area there was a gap in the aortic wall which was repaired using an autologous pericardium patch. Concerning her current anamnesis the patient reported at admission to our institution typical symptoms of dyspnoea in exercise according to NYHA III. The physical examination evaluated a distinct systolic ejection murmur in the right second intercostal space, although without a clear diastolic flow pattern. The angiography that had already been carried out in the admitting hospital showed a severe dysfunction of the prosthesis with a mean pressure gradient of 68 mmHg. Apart from the moderately restricted left ventricular function a slight mitral valve insufficiency could be observed. The bulbus angiography showed a clear, partially circumscribed ectasia in the area of the sinus of Valsalva (Figure 1). Thus, the indication for re-do surgery was ensured. The corresponding procedure was carried out under routine circumstances. The intraoperative finding presented itself to be congruent with the preoperative evaluated angiopraphic status. The aneurysm in the area of the pericardium patch was resected and the patient underwent renewed aortic valve replacement. The postoperative course, however, was not completely uneventful: Although stable haemodynamics could be guaranteed at any time without the support of catecholamines, postoperative mechanical ventilation was necessary for eight days. Besides that, a left-sided motoric dysfunction was proved as hemiparesis. Cranial computer tomography (CCT) showed ischaemic changes in the area of the right-sided medial cerebral artery. Apart from this, a diffuse but slight brain swelling could be. The clinical symptomatics was quickly retrograde so that five days after the extubation the patient could be discharged to the intensive care unit of the admitting hospital for further maintenance. After another stay of approximately four weeks in hospital there, the patient presented herself in an almost physiologic neurological status without cognitive dysfunction and was considered for rehabilitation.
Discussion
After the quite early establishment of open heart surgery the correction of congenital and acquired tissue defects has begun [8]. The underlying technical procedures are various and in some instances difficult. The literature frequently reports on the use of both synthetic patches and autologous material, such as pericardium [3, 14]. The use of autologous material is comparably difficult: The pericardium patch is used in a wide range, from the post-infarctial VSD correction to the intracardiac correction of the Tetralogy of Fallot [9]. The complications in those cases, which, however, mainly impair the patients’ outcomes, are represented by the development of aneurysms in the area of the employed patches. According to this case, the literature provides different incidences and refers to a high correlation to the current patient. Some authors even describe the development of aneurysms in the low-pressure-system, i.e. in the area of the right ventricular outflow tract. Different reports of such or comparable origins are summarized in Table I [10-13, 15-17]. The patient we are currently reporting on also received a pericardium patch in order to close a gap in the area of the aortic root that had occurred after the enlargement for aortic valve replacement many years before. The development of an aneurysm also occurred here, which had to be resected in the second re-do procedure in our institution. The postoperative course shows that different complications can appear in the complexity of second (re-do) procedures and are not to be underestimated. The alternatives to the pericardium or generally speaking to autologous material are controversially discussed in the current literature and firstly depend on the underlying disease.
Conclusions
Thus we draw the conclusion that autologous material should be used with a greater distance in the high-pressure system. Most citations of the literature show that the incidence of development of aneurysms under such circumstances is higher in comparison to other materials. That is why the use of synthetic agents, such as Dacron or PTFE, has to be discussed more intensively. In this context, however, as claimed by many other authors, the risk of postoperative infections comes to the fore [18, 19].

References
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