Background: The endovascular treatment of complex aortic aneurysms (thoracoabdominal, pararenal and juxtarenal) consists in the implantation of branched (b-EVAR, branched-EndoVascular Aneurysm Repair) or fenestrated (f-EVAR, fenestrated-EndoVascular Aneurysm Repair) endografts, with incorporation of the visceral and renal arteries through the placement of bridging stents. However, target vessel incorporation during the endovascular procedure may determine an increased technical difficulty and rate of complications during follow-up, such as target vessels’ endoleaks or occlusions. Some geometrical factors have been demonstrated to be associated with postoperative complications after b-EVAR and f-EVAR, with particular regard to target vessel instability. These postimplantation geometric analyses are nevertheless based on measurements taken on static images acquired with a 3D-CTA (tridimensional-computed tomography angiography) scan and hence they do not consider the dynamic changes occurring during the cardiac cycle. Objective: The aim of the present study was to conduct a kinetic analysis of the main aortic endograft and its associated bridging stents after treatment of complex aortic aneurysms with branched or fenestrated endograft, by using postoperative dynamic volumetric CTA. Methods: A review of prospectively collected single-center data was performed on selected patients who underwent the endovascular treatment of complex aortic aneurysm with branched or fenestrated endograft. A postoperative 4D-CTA scan was performed on these selected patients. From the ECG-triggered CTA acquisitions, 2D-t reconstructions were obtained along sagittal, frontal and axial plans including the main aortic endograft-bridging stents complex. All the measurements were then taken using the Horos medical imaging software (horosproject.org, Nimble Co LLC, Annapolis, Maryland). For branched stent grafts four geometric parameters were assessed: the vertical length (VL, distance between the branch cuff distal radiopaque marker and the origin of the target artery along the aortic centerline), the horizontal length (HL, horizontal distance between the main endograft and the aortic native wall next to the target vessel ostium), the branch alpha angle and the bridging stent beta angle. For the fenestrated endografts three geometric parameters were analysed: the vertical misalignment (VM, vertical distance along the aortic centerline between the midpoint of the fenestration and the midpoint of the target vessel at its origin), the horizontal misalignment (HM, angle between the midpoint of the fenestration and the midpoint of the target vessel ostium on CTA axial cuts) and the bridging stent alpha angle. Variations over time were described for each investigated parameter, reporting time as a percentage of the cardiac cycle. The statistical analysis is purely descriptive and focuses on the delta value of each parameter. Target vessel instability, defined as any target vessel-related complication leading to endoleak, aneurysm rupture, death, target vessel stenosis or occlusion needing reintervention, component separation or bridging stent fracture, was also investigated. Conclusion: This study has allowed to preliminarily demostrate that postoperative geometric parameters measured on 4D-CTA scans in patients previously treated with branched or fenestrated endografts are subjected to relevant variations during the cardiac cycle. Such dynamic changes could affect target vessel stability during follow-up. However, a higher number of patients and a longer follow-up are necessary in order to draw more solid conclusions.
Presupposti dello studio: Il trattamento endovascolare degli aneurismi aortici complessi (toracoaddominali, pararenali e iuxtarenali) consiste nell’utilizzo di endoprotesi branched (b-EVAR, branched-EndoVascular Aneurysm Repair) o fenestrate (f-EVAR, fenestrated-EndoVascular Aneurysm Repair), che permettono l’incorporazione delle arterie viscerali e renali tramite il posizionamento di bridging stent. Tuttavia, l’incorporazione dei vasi target rappresenta un fattore determinante nell’aumento della complessità tecnica della procedura d’impianto e le principali complicanze che si verificano nel follow-up sono costituite da endoleak ed occlusioni a carico dei vasi target stessi. Esistono alcuni fattori geometrici per i quali è stata dimostrata una stretta associazione alle complicanze postoperatorie di b-EVAR e di f-EVAR, in particolare in termini di instabilità dei vasi target. Queste analisi geometriche postoperatorie si sono tuttavia avvalse di misurazioni effettuate su immagini statiche ottenute tramite angioTC (angio-tomografia computerizzata), senza tenere in considerazione le modificazioni dinamiche che possono avvenire durante il ciclo cardiaco. Scopo dello studio: Lo scopo del presente studio è quello di condurre un’analisi cinetica dell’endoprotesi principale e dei bridging stent ad essa connessi in pazienti sottoposti a trattamento di aneurismi aortici complessi mediante tecnica b-EVAR o f-EVAR, utilizzando l’angioTC dinamica volumetrica postoperatoria. Materiali e Metodi: È stato condotto uno studio longitudinale prospettico monocentrico, includendo pazienti sottoposti ad esclusione endovascolare di aneurisma aortico complesso mediante endoprotesi branched o fenestrate. I pazienti selezionati sono stati sottoposti ad angioTC dinamica volumetrica postoperatoria. Dalle acquisizioni TC ECG-triggered sono state ottenute delle ricostruzioni 2D-t lungo piani di taglio sagittali, frontali ed assiali includenti il complesso endoprotesi-bridging stent. Tutte le misurazioni sono state eseguite con il software di imaging medico Horos (horosproject.org, Nimble Co LLC, Annapolis, Maryland). Per le endoprotesi branched sono stati valutati la distanza verticale (VL, distanza lungo la centerline aortica tra il marker radiopaco distale del branch e l’origine dell’arteria target), la distanza orizzontale (HL, distanza tra la parete dell’endograft aortico e la parete aortica in prossimità dell’emergenza dell’arteria target), l’angolo alpha del branch e l’angolo beta del bridging stent, mentre per le endoprotesi fenestrate sono stati analizzati il misalignment verticale (VM, distanza lungo la centerline aortica tra il punto centrale della fenestrazione ed il punto centrale del vaso target vicino alla sua origine), il misalignment orizzontale (HM, angolo tra il punto centrale della fenestrazione ed il punto centrale dell’ostio del vaso target) e l’angolo alpha del bridging stent. Per ogni paramentro è stato descritto l’andamento in funzione del tempo, misurato in termini di percentuale del ciclo cardiaco. L’analisi statistica condotta è di tipo descrittivo e si è focalizzata sullo studio del delta di ciascun parametro. E’ stata infine valutata l’instabilità dei vasi target. Conclusioni: Questo studio ha permesso di dimostrare, in via del tutto preliminare, che i parametri geometrici misurati con l’ausilio dell’angioTC dinamica in pazienti trattati mediante endoprotesi branched o fenestrate sono sottoposti a variazioni significative durante il ciclo cardiaco, che potrebbero influenzare la stabilità dei vasi target durante il follow-up. Sono tuttavia necessari una maggiore numerosità campionaria ed un follow-up più lungo per ottenere evidenze più solide.
Utilizzo dell’angioTC dinamica volumetrica per l’analisi cinetica dell’endoprotesi e dei vasi target in pazienti sottoposti a trattamento di aneurismi aortici complessi mediante endoprotesi branched o fenestrate
PARIS, MARIA CHIARA
2021/2022
Abstract
Background: The endovascular treatment of complex aortic aneurysms (thoracoabdominal, pararenal and juxtarenal) consists in the implantation of branched (b-EVAR, branched-EndoVascular Aneurysm Repair) or fenestrated (f-EVAR, fenestrated-EndoVascular Aneurysm Repair) endografts, with incorporation of the visceral and renal arteries through the placement of bridging stents. However, target vessel incorporation during the endovascular procedure may determine an increased technical difficulty and rate of complications during follow-up, such as target vessels’ endoleaks or occlusions. Some geometrical factors have been demonstrated to be associated with postoperative complications after b-EVAR and f-EVAR, with particular regard to target vessel instability. These postimplantation geometric analyses are nevertheless based on measurements taken on static images acquired with a 3D-CTA (tridimensional-computed tomography angiography) scan and hence they do not consider the dynamic changes occurring during the cardiac cycle. Objective: The aim of the present study was to conduct a kinetic analysis of the main aortic endograft and its associated bridging stents after treatment of complex aortic aneurysms with branched or fenestrated endograft, by using postoperative dynamic volumetric CTA. Methods: A review of prospectively collected single-center data was performed on selected patients who underwent the endovascular treatment of complex aortic aneurysm with branched or fenestrated endograft. A postoperative 4D-CTA scan was performed on these selected patients. From the ECG-triggered CTA acquisitions, 2D-t reconstructions were obtained along sagittal, frontal and axial plans including the main aortic endograft-bridging stents complex. All the measurements were then taken using the Horos medical imaging software (horosproject.org, Nimble Co LLC, Annapolis, Maryland). For branched stent grafts four geometric parameters were assessed: the vertical length (VL, distance between the branch cuff distal radiopaque marker and the origin of the target artery along the aortic centerline), the horizontal length (HL, horizontal distance between the main endograft and the aortic native wall next to the target vessel ostium), the branch alpha angle and the bridging stent beta angle. For the fenestrated endografts three geometric parameters were analysed: the vertical misalignment (VM, vertical distance along the aortic centerline between the midpoint of the fenestration and the midpoint of the target vessel at its origin), the horizontal misalignment (HM, angle between the midpoint of the fenestration and the midpoint of the target vessel ostium on CTA axial cuts) and the bridging stent alpha angle. Variations over time were described for each investigated parameter, reporting time as a percentage of the cardiac cycle. The statistical analysis is purely descriptive and focuses on the delta value of each parameter. Target vessel instability, defined as any target vessel-related complication leading to endoleak, aneurysm rupture, death, target vessel stenosis or occlusion needing reintervention, component separation or bridging stent fracture, was also investigated. Conclusion: This study has allowed to preliminarily demostrate that postoperative geometric parameters measured on 4D-CTA scans in patients previously treated with branched or fenestrated endografts are subjected to relevant variations during the cardiac cycle. Such dynamic changes could affect target vessel stability during follow-up. However, a higher number of patients and a longer follow-up are necessary in order to draw more solid conclusions.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/36525