Table of Contents  
Year : 2021  |  Volume : 8  |  Issue : 4  |  Page : 332-336

Role of CO2 angioplasty as a safe option in endovascular treatment of peripheral arterial disease in high-risk patients using dedicated automated OptiMed CO2 delivery system

1 Department of Interventional Radiology, Apollo Hospitals, Hyderabad, Telangana, India
2 Department of Radiology and Imaging Sciences, Apollo Hospitals, Hyderabad, Telangana, India

Date of Submission08-Feb-2021
Date of Decision31-Mar-2021
Date of Acceptance06-Apr-2021
Date of Web Publication9-Dec-2021

Correspondence Address:
Lakshmi Sudha Prasanna Karanam
Department of Interventional Radiology, Apollo Hospitals, Hyderabad, Telangana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijves.ijves_20_21

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Aim: The aim of this study was to emphasize the role of CO2 angioplasty using dedicated automatic OptiMed CO2 delivery system in patients with peripheral arterial disease (PAD) of high-risk group. Iodinated contrast media is harmful in all these patients of renal insufficiency with baseline creatinine >1.5 mg/dl. Methods: The present study is a retrospective analysis from a prospectively collected institutional review board-approved database. From April 2015 to June 2019, 44 patients (29 male patients and 15 female patients with a mean age of 68.5 years) underwent peripheral angioplasty using dedicated CO2 delivery system (OptiMed). All the patients were known diabetic with renal insufficiency due to chronic kidney disease (CKD). Demographic factors, clinical characteristics, and atherosclerotic risk factors were documented. Lesions included proximal and distal superficial femoral artery, popliteal, and below-the-knee vessels. Patients with chronic obstructive pulmonary disease, ventricular septal defects, and pulmonary vascular malformations were excluded from the study. Preliminary diagnosis by duplex scan was done in all the patients. Technical success, periprocedural events, and clinical outcomes were documented in all the patients. Results: Technical success was achieved in 43 cases (97.7%) which is described as successful balloon angioplasty resulting in increased vascularity of the distal limb due to improved distal runoff. Adequate imaging and successful intervention was achieved using OptiMed CO2 delivery system in majority of our patients. In one patient, the lesion could not be crossed and the patient had acute ST-elevation changes in electrocardiogram, and hence, the procedure was abandoned and the patient was shifted to cardiac care unit. Twenty-one patients complained of moderate pain which subsided with intra-arterial lidocaine. Four patients who complained of severe pain were given nerve block and sedation. There were no other intra- and postprocedural adverse events with stable renal parameters monitored up to 48 h. None of the patients required amputation after angioplasty in our study. Conclusion: With increasing burden of PAD in diabetic group, especially in CKD patients, angioplasty with dedicated CO2 delivery system is safe and effective with satisfactory outcome and should be considered as standard choice in this group of patients for limb salvage.

Keywords: Automated delivery, CO2 angioplasty, contrast-induced nephropathy

How to cite this article:
Karanam LS, Baddam SR, Ravikanti S P, Kumar K S. Role of CO2 angioplasty as a safe option in endovascular treatment of peripheral arterial disease in high-risk patients using dedicated automated OptiMed CO2 delivery system. Indian J Vasc Endovasc Surg 2021;8:332-6

How to cite this URL:
Karanam LS, Baddam SR, Ravikanti S P, Kumar K S. Role of CO2 angioplasty as a safe option in endovascular treatment of peripheral arterial disease in high-risk patients using dedicated automated OptiMed CO2 delivery system. Indian J Vasc Endovasc Surg [serial online] 2021 [cited 2022 Aug 15];8:332-6. Available from:

  Introduction Top

Incidence of peripheral arterial disease (PAD) is increasing worldwide with increasing prevalence in diabetic mellitus population causing more diffuse involvement of peripheral vessels, predominantly below-the-knee (BTK) arteries.[1] Risk of PAD is fourfold higher in diabetic patients.[1] These patients often have other comorbid conditions, with chronic kidney disease (CKD) being one of the common associations.[2] Diabetic patients with PAD often have an increased risk of contrast-induced nephropathy (CIN), especially in cases of preexisting CKD.[3] The association of PAD and CKD causes increased morbidity in the patients undergoing endovascular therapy for revascularization.[4] PAD in this group is often associated with atheromatous changes in other vascular territories, predominantly coronary and cerebral arteries. CIN is a cause of acquired acute renal failure resulting in increasing incidence of hospitalization of these patients with acute kidney injury.[5]

These patients with altered renal parameters often require treatment with endovascular intervention for improving limb vascularity which plays an important role for limb salvage. The use of CO2 in these patients is a good alternative choice for the interventional management in patients with CKD.[6] CO2 is nonallergic, nonnephrotoxic, low viscous, inexpensive, highly compressible. Its use in the vascular system as a contrast agent is first described by Hawkins et al. CO2 displaces the blood column and hence can be used with smaller French catheters even with the presence of guidewire in situ.[7] The risk of CIN has been overcome by the use of CO2 as a contrast agent instead of conventional iodinated contrast media (ICM) with dedicated automated CO2 delivery system, and by using advanced digital subtraction angiography (DSA) with hybrid techniques, the limitations previously described concerning the safety and accuracy have been resolved.[8]

The main limitation of CO2 use in the past is because of unreliability of injection, discomfort, and suboptimal yield and due to the issues of contamination as described in previous studies.[9],[10],[11] Alternate agents like gadolinium have been used in these patients, however, its use is limited by its cost association of nephrogenic systemic fibrosis in patients with CKD.[12] Hence, CO2 is the presently available safe and efficient contrast agent for diagnostic and therapeutic intervention of PAD in CKD group.

Recent development of dedicated delivery system improved the diagnostic accuracy and efficacy of CO2 as a contrast agent in the group of patients prone to CIN. The use of automated controlled dedicated CO2 injection system (OptiMed) helped us overcome these problems.

  Methods Top

Between April 2015 and June 2019, 789 endovascular diagnostic and endovascular therapeutic procedures were done for peripheral vessels, of which 44 patients underwent angioplasty for PAD with CO2 delivery system. All the patients were known diabetics with creatinine level >1.5 mg/dl.

Twenty-nine male patients and 15 female patients with a mean age of 68.5 years (60–77 years) underwent therapeutic procedure using automated OptiMed CO2 delivery system. All patients had symptoms and signs of critical lower-limb ischemia who underwent thorough clinical examination and color Doppler study. The symptoms varied from claudication pain, rest pain, and the presence of nonhealing progressing ulcer in our patients; 16 patients had disease in femoropopliteal segments; 18 had severe disease in BTK arteries (anterior tibial artery, peroneal artery, and posterior tibial artery); and 10 patients had concomitant disease of both femoral-popliteal and BTK vessels. All the patients were on medical management with double-antiplatelet agents (ecosprin 150 mg and clopidogrel 75 mg) and underwent angioplasty in the same setting of diagnostic angiogram. Patients with chronic obstructive pulmonary disease, ventricular septal defect, and pulmonary malformations were excluded. All the patients had baseline creatinine >1.5 mg/dl.

Automated CO2 delivery system

The CO2 is delivered by closed system to prevent contamination. We used OptiMed angioset (OptiMed, Ettlingen, Germany) in all the patients. CO2-angioset [Figure 1] has a gas chamber containing pure medical CO2, pressure relief valve with supply line, and stopcock with a 90° rotary valve. One hundred milliliter syringe is connected to the patient with 150 cm connecting tube. The system is rinsed by turning the stopcock back and forth holding the syringe vertically to avoid contamination. The CO2 pressure reduction valve is preset to 1.3 bars and enables a safe withdrawal of pure medical carbon dioxide from gas cylinders. The two-stage pressure reduction valve maintains a safe and constant pressure. In all our cases, the limb is elevated using a cushion with a tilt of 15°–20°. Care was taken to safely purge the CO2 set and avoid any air contamination before connection to the patient. We used a CO2 volume of 40 ml for the femoropopliteal segment and 20 ml for selective imaging of the BTK arterial segments. To avoid discomfort, intra-arterial lidocaine was used whenever required. All the patients received mild sedation with fentanyl and midazolam. A washout time of 2 min was allowed between series to decrease the pain. Intra-arterial nitroglycerin 100–200 μg is used to enhance gas flow and filling of the distal arteries in some of the patients. Angiography was performed first using a 4F diagnostic catheter, and the catheter is placed distally for selective injections. Heparin of 5000 units was administered. The quality of the BTK infrapopliteal arterial angiography images was improved by limb elevation using a cushion. DSA images were acquired with increased frame rate of 7 frames/s. After the occlusion was crossed and recanalized by a guidewire, the diseased segment was then balloon dilated by the predetermined balloon as per choice of the operator. The blood pressure, respiratory rate, and electrocardiogram (ECG) were carefully monitored during the procedure. The problem of breaking the contrast column was overcome by using stacking software for the DSA images which increases the quality of images and therefore the diagnostic accuracy.
Figure 1: Automated CO2 delivery system with various components and the depiction of pressure relief valve

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  Results Top

All the patients underwent CO2 DSA angioplasty using dedicated automated CO2 OptiMed system. A total of 44 patients underwent angiogram followed by transluminal balloon angioplasty of femoropopliteal and BTK arteries. The diagnostic findings of the lesions correlated with baseline duplex scan in all the patients who subsequently underwent angioplasty in the same setting after taking informed consent for the procedure. Demonstrative cases are illustrated in [Figure 2], [Figure 3], [Figure 4], [Figure 5].
Figure 2: Baseline CO2 angiogram showing tight stenosis of the popliteal artery (a) with increased flow across the stenotic segment post procedure (b) and increased antegrade flow with good opacification of the plantar arch (c)

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Figure 3: Preprocedure CO2 angiogram showing near total occlusion of popliteal artery (a) with good revascularisation and distal flow established after CO2 angioplasty (b)

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Figure 4: Left popliteal CO2 angiogram demonstrating near total occlusion of Posterior tibial artery with no antegrade flow (a) with good flow restored after CO2 angioplasty (b)

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Figure 5: Left CFA CO2 angiogram showing atheromatous changes with proximal SFA and profunda arteries (a). Selective SFA angiogram angiogram showing tight stenosis (b) with good revascularisation and antegrade flow post CO2 angioplasty in the SFA (c)

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Technical success was achieved in 43 cases (97.7%). Diagnostically adequate and accurate images were obtained in all the 44 patients using postprocessing techniques and stacking software wherever necessary. Subsequent successful angioplasty was done in 43 patients with good results. In one individual with a prior known history of coronary artery disease, the patient complained of severe chest pain due to acute myocardial infarction during the procedure documented as acute ST-segment elevation changes in ECG, and hence, the procedure was abandoned and the patient was shifted to cardiac care unit. Twenty-one patients complained of moderate pain which subsided with intra-arterial lidocaine. Four patients who complained of severe pain were given nerve block and sedation. None of the patients required general anesthesia for the procedure which may be attributed to comparatively lower volumes of CO2 and selective injections with close proximity to lesions which was possible because of dedicated CO2 delivery system. There were no other intra- and postprocedural adverse events with stable renal parameters monitored up to 48 h. Diagnosis and angioplasty were based on CO2 images alone in all our patients, and we did not use ICM in any of our patients. Doppler was done in all the patients which helped as the baseline to look for the desired segments. In general, repeat angios were required in BTK vessels due to artifacts as a response to pain and due to breaking of contrast columns. However, adequate images for intervention were obtained in all the cases, and postprocedure documentation of vascularity was well done with the use of stacking software. None of our patients had altered renal parameters as compared to the preprocedure levels.

  Discussion Top

CIN is a major concern in patients requiring endovascular intervention, especially in patients with preexisting renal disease with a reported incidence of 20%.[13],[14]

CO2 has been used as a contrast agent since 1971.[7] The main advantage of CO2 is lack of iodine and nonallergic which makes it well suited to prevent CIN in patients with renal dysfunction and impaired renal clearance.[7] Its use is limited to infradiaphragmatic level to prevent inadvertent embolic events due to air-block phenomenon. DSA equipment is required for CO2 angiography.[15] Even small volumes of ICM along with CO2 in diabetic patients with PAD and preexisting chronic renal insufficiency can result in a significant increased risk of worsening renal function as described by Spinosa et al.[16] In our present, we did not any use iodine contrast media or gadolinium contrast agents to supplement CO2 angiography in any of our patients.

Previous studies compared the use of ICM and automated CO2 delivery system with angiodroid for diagnostic purposes and obtained high-quality images with statistically no significant differences between both the groups. In our patients, we did not use ICM due to preexisting renal condition, and inaccuracy of images whenever required was improved by using the stacking software. Selective and superselective approaches helped us in using low volume of CO2 as compared to the homemade manual systems.[17]

The use of automated delivery system with DSA acquires getting good-quality images and thus eliminates the inaccuracy of handheld injections.[10]

CO2 is soluble low viscous and highly compressible gas. It cannot be visually distinguished from air, hence prevention of contamination is very important which causes severe complications.[18] The use of air-tight systems such as OptiMed in our study helped us overcome these unique concerns regarding the use of CO2. High-resolution DSA is used in our study for CO2 imaging.

The issue of buoyancy due to the use of CO2 was overcome in our study by elevation of examining limb with the cushion. Buoyancy is a problem, especially in large vessels, because CO2 bubbles flow along the anterior part of the vessel, with incomplete blood displacement along the posterior portion. However, our study group comprises vessels <10 mm in diameter (superficial femoral artery, popliteal, and BTK vessels) where the CO2 displaced the blood in >80% of the lumen. Each acquisition may not have the entire vessel of interest opacified due to this displacement property, hence postprocessing techniques help in getting good accuracy and planning of intervention treatment. Intra-arterial injection of 100–200 mg of nitroglycerin whenever required increased gas flow and filling of the distal arteries.[18],[19],[20] No major complications occurred in our study which required active treatment. Since ICM was not used in our study, we did not have any bias in interpreting the CO2 DSA images as reported in studies comparing ICM and CO2 DSA.[10]

Palena et al. in their study evaluated the diagnostic accuracy of automated CO2 angiography in patients with diabetes and CKD. In their series, all the patients underwent subsequent angiogram with iodinated contrast medium.[21] The interobserver variability of independently reviewed DSA images was found to be very low (κ = 0.89). There is no significant (P = 0.197), diagnostic accuracy difference between CO2 angiography and iodinated contrast medium, thus supporting the use of CO2 contrast by automated delivery system alone for diagnostic and therapeutic interventions as described in our present study.

The limitations in our study include the small group of patients and retrospective design of the analysis. Only results of CO2 DSA were used in all our patients for further treatment of revascularizations which helped in limb salvage by successful endovascular therapeutic intervention. The dedicated automated OptiMed system used by us eliminated the cumbersome methods involving handheld injections in homemade delivery system, and all the advantages of CO2 as contrast media were well utilized by overcoming the complexity of the delivery of CO2 gas in our study.

  Conclusion Top

CO2 can be used safely in CKD patients and OptiMed delivery system helped us in delivering successful treatment of PAD and critical limb ischemia in the high group of diabetic and CKD patients with adequate accurate images even in infrapopliteal segments. CO2 delivery system should be considered as a standard and feasible option for diagnosis and therapeutic option in these patients without the use of any adjunct contrast media as discussed in our present study. Further large group of cohorts is needed to validate the same.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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