Pseudoaneurysm Formation After Medtronic Freestyle Porcine Aortic Bioprosthesis Implantation: A Word of Caution

Abstract

Background A growing literature describes aneurysmal deterioration after implantation of the stentless porcine aortic Medtronic Freestyle bioprosthesis (MFB; Medtronic Inc, Minneapolis, MN), with some suggesting inadequate tissue fixation with immune response as a cause. However, disjointed reports make the significance of these findings difficult to interpret. We address this concern by aggregating available data. Methods We reviewed institutional data, the Food and Drug Administration’s Manufacturer and User Facility Device Experience registry, and the medical literature for mention of aneurysm or pseudoaneurysm after MFB. Case details were aggregated, and the rate of aneurysmal deterioration was estimated. Immunohistopathologic examination of institutional explanted specimens was performed to elucidate a cause. Results We found 42 cases of aneurysmal deterioration with adequate detail for analysis; all occurred with full root replacement and valve sizes ranging from 23 to 29 mm. The rate of aneurysmal deterioration considering all data sources was 1.1% (9 of 851; 95% confidence interval, 0.5% to 2.0%) vs 4.7% (4 of 86; 95% confidence interval, 1.3% to 11.5%) at our institution, where yearly surveillance imaging is performed. Rate of aneurysmal deterioration appeared constant until 5 years after the operation; however, events are reported out to 10 years. Consistent with previous reports, histopathology demonstrated an immune cell infiltrate in areas of MFB wall breakdown. Conclusions Aneurysmal deterioration is an increasingly described complication of MFB implantation as a full root, with an incidence as high as 4.7%. Given the observed immune reaction and lack of occurrence in smaller (19-mm and 21-mm) valve sizes, inadequate pressure fixation of larger valves is a potential etiology. Patients with MFB require annual surveillance imaging, and consideration of this complication should factor into preoperative decision making because treatment mandates redo root replacement, which may not be feasible in high-risk patients.

Imaging Surveillance After Proximal Aortic Operations: Is it Necessary?

“…The subgroup of reoperative thoracic aortic surgical patients presents in itself a unique challenge, with perioperative mortality ranging from 7% to 15% compared with 3% to 4% in the elective setting [1–10]. Thoracic aortic reoperations may be required for a multitude of reasons, including chronic/residual dissection, progression of aortic disease, anastomotic pseudoaneurysm, endocarditis or deterioration of bioprosthetic devices, graft infection, or valvular insufficiency, among others [6, 9, 11–14]. …”

Long Term Outcomes Following Freestyle Stentless Aortic Bioprosthesis Implantation: An Australian Experience

“…Although isolated to one occurrence in this series, such post-operative pathology has been noted in prior case reports, and may have an immunoreactive or infective aetiology [31,32]. In larger case series, however, the incidence of this post-operative complication is similarly very low [11,33].…”

Valved conduits in pediatric cardiac surgery

“…Впервые такой кондуит был имплантирован человеку в 1992 г., а в 1997 г. права на продукт приобрела компания «Medtronic Inc.», (Minneapolis, MN), которая запустила массовое производство данного продукта [54]. В настоя-щее время ксенокондуит Freestyle используется во многих центрах, чаще всего -для протезирования клапана аорты [55,56].…”

“…), отсутствие малых диа-метров кондуита (менее 19 мм) для новорожденных детей и младенцев, недостаточная длина трубчатой части, по-этому у большинства детей имплантат удлиняют с помо-щью заплат из ксеноперикарда, кондуитов из полите-трафторэтилена или дакрона [12,17,[54][55][56].…”

“…По данным B. Englum и соавт., чаще всего они протекают бессимптомно и являются находкой при диагностическом исследовании, однако некоторые пациенты испытывают симптомы сердечной недостаточ-ности вследствие сдавления правого желудочка или аор-то-легочной фистулы; описаны и летальные случаи вследствие тромбоэмболии легочной артерии [54]. Ос-новными причинами образования аневризм или псевдо-аневризм авторы называют иммунологические реакции, а также неблагоприятные гемодинамические условия, так как данные осложнения наиболее часто развиваются у реципиентов кондуитов Freestyle небольших диаметров (19-21 мм).…”