CO2 Automated Angiography in Endovascular Aortic Repair Preserves Renal Function to a Greater Extent Compared with Iodinated Contrast Medium. Analysis of Technical and Anatomical Details

Advanced Imaging Techniques for Complex Endovascular Aortic Repair: Preoperative, Intraoperative and Postoperative Advancements

BACKGROUND

Endovascular aortic repair (EVAR) requires extensive preoperative, intraoperative, and postoperative imaging for planning, surveillance, and detection of endo-leaks. There have been manyadvancements in imaging modalities to achieve this purpose. This review discussed different imaging modalities used at different stages of treatment of complex EVAR.

METHODS

We conducted a literature review of all the imaging modalities utilized in EVAR by searching various databases.

RESULTS

Preoperative techniques include analysis of images obtained via modified central line using analysis software and intravascular ultrasound. Fusion imaging (FI), carbon dioxide (CO2) angiography, intravascular ultrasound, and Fiber Optic RealShape (FORS) technology have been crucial in obtaining real-time imaging for the detection of endo-leaks during operative procedures. Conventional imaging modalities like computed tomography (CT) angiography (CTA) and magnetic resonance (MR) angiography are still employed for postoperative surveillance along with computational fluid dynamics and contrast-enhanced ultrasound (CEUS). The advancements in artificial intelligence (AI) have been the breakthrough in developing robust imaging applications.

CONCLUSIONS

This review explains the advantages, disadvantages, and side-effect profile of the abovementioned imaging modalities.

CO2 Angiography in the Standard and Complex Endovascular Repair of the Abdominal Aorta-A Narrative Review of the Literature

Background/Objectives: Carbon dioxide digital-subtraction angiography (CO2-DSA) is an increasingly adopted technique in endovascular aortic repair (EVAR) and fenestrated/branched EVAR (F/B-EVAR); it is used to reduce the amount of iodinate contrast medium (ICM) and prevent postoperative renal function worsening (PO-RFW). Our aim is to report results from the literature on EVAR and F/B-EVAR procedures using CO2-DSA, together with wider applications in aortic endovascular treatment. Methods: We performed a literature review by searching electronic databases for published data on CO2-DSA during EVAR and F/B-EVAR procedures. The endpoints were postoperative renal function worsening (PO-RFW) and efficacy of intraoperative arterial visualization. Further, applications of CO2 for thoracic endovascular aortic repair (TEVAR) were described. Results: Seventeen studies reporting results on CO2-DSA in EVAR (644 patients) were retrieved. Overall, 372 (58%) procedures were performed with CO2 alone, and 272 (42%) were performed with CO2+ICM. Eight studies analyzed the effect of CO2-DSA angiography on PO-RFW; four studies showed a significantly lower rate of PO-RFW compared to ICM. Five studies (153 patients) analyzed intraoperative arterial visualization with CO2-DSA; renal and hypogastric arteries were effectively visualized in 69% and 99% of cases, respectively. The use of CO2-DSA in F/B-EVAR has not been widely investigated. The largest series reported that PO-RFW was lower in the CO2 vs. ICM group. Conclusions: Carbon dioxide is widely applied in modern aortic endovascular treatment. CO2-DSA for EVAR and F/B-EVAR is an efficient technique for reducing PO-RFW while allowing acceptable arterial intraoperative visualization.

The efficacy of CO2 angiography in the endovascular treatment of an acute iliac pseudoaneurysm

CO2 angiography has been used extensively for the endovascular treatment of aorto-iliac and femoral-popliteal-tibial pathologies, specifically in patients with chronic kidney disease or allergy to iodinated contrast medium (ICM). However, its use in urgent treatment of an acute pseudoaneurysm has never been described before. We report a case of a 39-year-old woman, allergic to iodine, with a recent kidney transplant, who presented in the emergency room with severe pain in the left iliac fossa. Angio CT-scan showed an acute pseudoaneurysm of the left common iliac artery. She was emergently treated with a stent-graft and CO2 was used as main contrast medium. The intraoperative angiographies performed with carbon dioxide showed very well the rupture site and the pseudoaneurysm; the latter were more clearly visible with CO2 compared with ICM. The reported case shows the efficacy of CO2 as contrast medium also in urgent settings and arterial ruptures. The lower viscosity of CO2 probably leads to an easier diffusion through the arterial lesion into the pseudoaneurysmal sac. Therefore, in this case the use of carbon dioxide not only guaranteed prevention of massive allergic reaction to iodine and preservation of postoperative renal function, but also resulted in higher image quality in the operating room.

Total iodine contrast-free strategy for the endovascular management of abdominal aortic aneurysms in chronic kidney disease patients: a pilot study

OBJECTIVES

To retrospectively evaluate the feasibility and effectiveness of the endovascular treatment of patients with abdominal aortic aneurysm (AAA) and chronic kidney disease (CKD) without the need for using iodinated contrast media (ICM) throughout the diagnostic, therapeutic and follow-up pathway.

METHODS

A retrospective review of prospectively collected data concerning 251 consecutive patients presenting an abdominal aortic or aorto-iliac aneurysm who underwent endovascular aneurysm repair (EVAR) from January 2019 to November 2022 at our academic institution was performed in order to identify patients with feasible anatomy with respect to manufacturers' instructions for use (IFU) and with CKD. Patients whose preoperative workout included duplex ultrasound (DUS) and plain computed tomography (pCT) for pre-procedural planning were extracted from a dedicated EVAR database. EVAR was performed with the use of carbon dioxide (CO₂) as contrast media of choice, whereas follow-up examinations consisted of either DUS, pCT or contrast-enhanced ultrasound (CEUS). Primary endpoints were technical success, perioperative mortality and early renal function variations. Secondary endpoints were all-type endoleaks (EL) and reinterventions, mid-term aneurysm-related and kidney-related mortality.

RESULTS

Forty-five patients had CKD and were treated electively (45/251, 17.9%). Of them, seventeen patients were managed with a total ICM-free strategy and constituted the object of the present study (17/45, 37.8%; 17/251, 6.8%). In seven cases an adjunctive planned procedure was performed (7/17, 41.2%). No intraoperative bail-out procedures were needed. This extracted cohort of patients presented similar mean preoperative and postoperative (at discharge) GFRs values, 28.14 (SD 13.09; median 28.06, IQR 20.25) ml/min/1.73m² and 29.33 (SD 14.61; median 27.35, IQR 22) ml/min/1.73m² respectively (p= .210). Mean follow-up was 16.4 months (SD 11.89; median 18, IQR 23). During follow-up no graft-related complications occurred in terms of either thrombosis, type I or III EL, aneurysm rupture or conversion. The mean GFR at follow-up was 30.39 ml/min/1.73m² (SD 14.45; median 30.75, IQR 21.93), with no significant worsening in comparison with pre and postoperative values (p= .327 and p= .856 respectively). No aneurysm- or kidney-related deaths occurred during follow-up.

CONCLUSIONS

Our initial experience shows that total iodine contrast-free AAA endovascular management in patients with CKD may be feasible and safe. Such an approach seems to guarantee the preservation of residual kidney function without increasing the risks of aneurysm-related complication in the early and midterm postoperative period and it could be considered even in case of complex endovascular procedures.

The optimal operative protocol to accomplish CO2-EVAR resulting from a prospective interventional multicenter study

OBJECTIVES

Carbon dioxide (CO₂) angiography for endovascular aortic repair (CO₂-EVAR) is used to treat abdominal aortic aneurysms (AAAs), especially in patients with chronic kidney disease or allergy to iodinated contrast medium (ICM). However, some technical issues regarding the visualization of the lowest renal artery (LoRA) and the best quality image through angiographies performed from pigtail or introducer sheath are still unsolved. The aim of this study was to analyze different steps of CO₂-EVAR to create an operative standardized protocol.

METHODS

Patients undergoing CO₂-EVAR were prospectively enrolled in five European centers from 2019 to 2021. CO₂-EVAR was performed using an automated injector (pressure, 600 mmHg; volume, 100 cc); a small amount of ICM was injected in case of difficulty in LoRA visualization. LoRA visualization and image quality (1 = low, 2 = sufficient, 3 = good, 4 = excellent) were analyzed at different procedure steps: preoperative CO₂ angiography from pigtail and femoral introducer sheath (first step), angiographies from pigtail at 0%, 50%, and 100% of proximal main body deployment (second step), contralateral hypogastric artery (CHA) visualization with CO₂ injection from femoral introducer sheath (third step), and completion angiogram from pigtail and femoral introducer sheath (fourth step). Intraoperative and postoperative CO₂-related adverse events were also evaluated. χ² and Wilcoxon tests were used for statistical analysis.

RESULTS

In the considered period, 65 patients undergoing CO₂-EVAR were enrolled (55/65 [84.5%] male; median age, 75 years [interquartile range (IQR), 11.5 years]). The median ICM injected was 17 cc (IQR, 51 cc); 19 (29.2%) of 65 procedures were performed with 0 cc ICM. Fifty-five (84.2%) of 65 patients underwent general anesthesia. In the first step, median image quality was significantly higher with CO₂ injected from femoral introducer (pigtail, 2 [IQR, 3] vs introducer, 3 [IQR, 3]; P = .008). In the second step, LoRA was more frequently detected at 50% (93% vs 73.2%; P = .002) and 100% (94.1% vs 78.4%; P = .01) of proximal main body deployment compared with first angiography from pigtail; similarly, image quality was significantly higher at 50% (3 [IQR, 3] vs 2 [IQR, 3]; P ≤ .001) and 100% (4 [IQR, 3] vs 2 [IQR, 3]; P = .001) of proximal main body deployment. CHA was detected in 93% cases (third step). The mean image quality was significantly higher when final angiogram (fourth step) was performed from introducer (pigtail, 2.6 ± 1.1 vs introducer, 3.1 ± 0.9; P ≤ .001). The intraoperative (7.7%) and postoperative (12.5%) adverse events (pain, vomiting, diarrhea) were all transient and clinically mild.

CONCLUSIONS

Preimplant CO₂ angiography should be performed from femoral introducer sheath. Gas flow impediment created by proximal main body deployment can improve image quality and LoRA visualization with CO₂. CHA can be satisfactorily visualized with CO₂ alone. Completion CO₂ angiogram should be performed from femoral introducer sheath. This operative protocol allows performance of CO₂-EVAR with 0 cc or minimal ICM, with a low rate of mild temporary complications.