Photon-counting Computed Tomography (PCCT) is a promising imaging technique. Using detectors that count the number and energy of photons in multiple bins, PCCT offers several advantages over conventional CT, including a higher image quality, reduced contrast agent volume, radiation doses, and artifacts. Although PCCT is well established for cardiac imaging in assessing coronary artery disease, its application in aortic imaging remains limited. This review summarizes the available literature and provides an overview of the current use of PCCT for the diagnosis of aortic imaging, focusing mainly on endoleaks detection and characterization after endovascular aneurysm repair (EVAR), contrast dose volume, and radiation exposure reduction, particularly in patients with chronic kidney disease and in those requiring follow-up CT.

BACKGROUND: The carotid stent design may influence the risk of embolization during carotid artery stenting. The aim of the study was to assess this risk by comparing the quantity of embolized material captured by filters during carotid artery stenting, using different stent designs. METHODS: We conducted a single-center retrospective study of patients undergoing carotid artery stenting for asymptomatic carotid stenosis >70% (2010–2022) in a tertiary academic hospital (Padua University Hospital, Italy). Carotid stents were classified according to their design as open-cell (OCS), closed-cell (CCS), or micromesh stents (MMS). A distal filter protection was used in all patients, and the amount of captured embolized particles was semiautomatically analyzed using a dedicated software (Image-Pro Plus, Media Cybernetics). Primary end point was embolic filter debris (EFD) load, defined as the ratio of the filter area covered by particulate material to the total filter area. Secondary end points were 30 days major stroke and death. RESULTS: Four-hundred-eighty-one carotid artery stentings were included; 171 (35%) using an OCS, 68 (14%) a CCS, and 242 (50%) a MMS. Thirty-days mortality was 0.2% (n=1) and major stroke rate was 0.2% ( P =0.987). Filters of patients receiving MMS were more likely to be free from embolized material (OCS, 30%; CCS, 13%; MMS, 41%; P <0.001) and had a lower EFD load (OCS, 9.1±14.5%; CCS, 7.9±14.0%; MMS, 5.0±9.1%; P <0.001) compared with other stent designs. After stratification by plaque characteristics, MMS had a lower EFD load in cases of hypoechogenic plaque (OCS, 13.4±9.9%; CCS, 10.9±8.7%; MMS, 6.5±13.1%; P 15 mm (OC, 10.2±15.3; CC, 8.6±12.4; MM, 8.2±13.6; P <0.001), and preoperative ipsilateral asymptomatic ischemic cerebral lesion (OCS, 12.9±16.8%; CCS, 8.7±19.5%; MMS, 5.4±9.7%; P <0.001). After multivariate linear regression, use of MMS was associated with lower EFD load ( P =0.038). CONCLUSIONS: The use of MMS seems to be associated with a lower embolization rate and EFD load, especially in hypoechogenic and long plaques and in patients with a preoperative evidence of asymptomatic ischemic cerebral lesion.

The aim of this study was to investigate the outcomes of primary determinate and indeterminate target vessel endoleaks (TVELs) after fenestrated-branched endovascular aortic repair (F-BEVAR). We conducted a single-center retrospective study (2014-2023) on F-BEVAR for thoracoabdominal (TAAAs) or pararenal aortic aneurysms (PRAAs). TVELs were classified as "primary" if present at the first postoperative computed tomography angiogram. Endoleaks were defined "determinate" (dELs) if the cause (type Ic or IIIc) and implicated target vessel were identifiable and "indeterminate" (iELs) if contrast enhancement was detectable at the level of fenestrations/branches without any evident source. Endoleaks involving multiple inflows (type II and target vessels) were defined as "complex" (cELs). Endpoints were endoleak spontaneous resolution, 1-year aneurysm sac failure to regress (>5 mm diameter decrease), and 4-year endoleak-related secondary interventions. Kaplan-Meier estimates and Cox regression were used for the analysis. There were 142 patients with JRAAs/PRAAs (n = 85; 60%) or TAAAs (n = 57; 40%), with 513 target arteries incorporated through a fenestration (n = 294; 57%) or directional branch (n = 219; 43%). Fifty-nine primary TVELs (12%) were identified in 35 patients (25%), a dEL in 20 patients (14%) and iEL in 15 (11%); 22 (15%) had a determinate or indeterminate cEL. Overall spontaneous resolution rate was 75% (95% confidence interval [CI], 51%-87%) at 4 years. cELs (odds ratio [OR], 5.00; 95% CI, 1.10-49.4; P < .001) and iELs after BEVAR (OR, 9.43; 95% CI, 3.41-56.4; P = .002) were more likely to persist >6 months, and persistent forms were associated with sac failure to regress at 1 year (OR, 1.72; 95% CI, 1.03-12.59; P = .040). Overall freedom from endoleak-related reinterventions was 85% (95% CI, 79%-92%) at 4 years, 92% (95% CI, 87%-97%) for those without primary TVELs and 62% (95% CI, 46%-84%) for those with any primary TVEL (P < .001). In particular, cELs (hazard ratio, 1.94; 95% CI, 1.4-18.81; P = .020) were associated with an increased need for reintervention. In case a secondary intervention was needed, iEL or cEL had an increased risk for multiple secondary procedures (hazard ratio, 2.67; 95% CI, 1.22-10.34; P = .034). Primary TVELs are frequent after F-BEVAR, and a clear characterization of the endoleak source by computed tomography angiogram is not possible in 40% of patients. Most primary TVELs spontaneously resolve, but during follow-up, patients with any primary TVEL experience a worsened freedom from endoleak-related reinterventions that is mostly driven by persistence of cELs and post-BEVAR iELs. Multiple secondary procedures may be required in case of iELs or cELs.

This review synthetizes recent literature about in-situ aortic reconstructions for abdominal aortic graft or endograft infections (AGEIs), aiming to report outcomes individually related to currently available vascular substitutes (VSs). We performed a systematic review of all published literature from January 2005 to December 2022. We included articles reporting on open surgical treatment of abdominal AGEIs, with removal of the infected graft and in-situ reconstruction with biological or prosthetic material. Articles not distinguishing between abdominal and thoracic aortic-related outcomes were excluded, as well as studies reporting on cumulative in-situ and extra-anatomic reconstruction results. Of 500 records identified through database searching (Pubmed: 226; Embase: 274), 8 of them were included in the present review. Overall, 30-days mortality rate was 8.7% (25/285), while the most frequent early complications were respiratory adverse events (46/346, 13.3%) and renal function deterioration (26/85, 30%). In 250/350 cases (71.4%), a biological VS was utilized. In 4 articles, the outcomes of different types of VSs were presented jointly. Patients analyzed in the remaining 4 reports were sorted in a "biological" and a "prosthetic" group (BG and PG). The cumulative mortality rate of the BG and PG were 15.6% (33/212) and 27% (9/33), respectively, while graft reinfection was 6.3% (15/236) in the BG, and 9% (3/33) in the PG. The cumulative mortality rate reported in articles focused on autologous veins was 14.8% (30/202), while their 30-days reinfection rate was 5.7% (13/226). Since abdominal AGEIs are uncommon conditions, literature focused on direct comparison between different types of VSs is scarce, particularly when related to materials other than autologous veins. Although we found a lower overall mortality rate in patients treated with biological material or with autologous veins only, in recent reports prosthesis provide promising results in terms of mortality and reinfection rate. However, none of the available studies distinguish and compares different types of prosthetic material. Large multicenter studies are advisable, especially focused on different types of VSs and their comparison.

The objective of the study was to investigate the safety, efficacy, and early outcomes of a novel standardised approach to 4-fenestrated physician modified endograft (sPMEG) in the treatment of very large and urgent complex abdominal aortic aneurysms (cAAAs). Prospective multicentre study (S.PH.E.RE., Standardized Physician-modified 4-fenestrated Endograft Registry). The Valiant Captivia endograft (Medtronic, Minneapolis, MN, USA) was used for on bench modifications. Planning of fenestration position, technique, and procedure were standardised across the participating centres. Primary endpoints were technical success and early mortality. Secondary endpoints were sPMEG instability, major adverse events, and re-intervention at 30 days. Graft geometrical integrity and target vessel to fenestration misalignment (TV-FM) were evaluated on post-operative computed tomography angiogram. There were 50 cAAAs from 13 centres with a median follow up of 8 months. Mean age was 78 ± 18 years, with a Society for Vascular Surgery comorbidity score of 15 ± 5 and a mean maximum aneurysm diameter of 75 ± 19 mm. There were 9 (18%) short neck, 18 (36%) juxtarenal, 15 (30%) pararenal abdominal aortic, and 8 (16%) Extent IV thoraco-abdominal aneurysms. Thirty-two patients (64%) were treated electively, while 13 (26%) had a symptomatic and 5 (10%) had a ruptured aneurysm. Graft modification time was 128 ± 33 minutes, and total operating time was 196 ± 96 minutes. No intra-operative graft related complications were reported. Overall technical success rate was 96%, with failure to cannulate two target renal vessels. Thirty day mortality was 0%, and the major adverse event rate was 8%. Related re-intervention occurred in 4%. No graft related type I endoleak, disconnection, or fracture were reported. All patients had successful early follow up imaging, and post-implantation geometrical analysis showed 100% integrity of the main graft and 194 reinforced fenestrations. Vertical TV-FM was detected in 1% , and horizontal TV-FM in 2%. This real life registry using 4-fenestrated sPMEG for the treatment of very large and urgent cAAAs showed excellent technical implantation safety, efficacy, and early outcomes, despite the high comorbidity rate of patients. Longer term follow up is needed to better define the clinical role of this standardised PMEG approach.