We conducted a retrospective review of 37 cases involving patients who underwent VSF procedures at a single center between December 2022 and December 2023. Informed consent was obtained from all participants, and they were scheduled follow-up visits for a minimum duration of 12 months. This study was conducted in accordance with the Declaration of Helsinki.

Inclusion criteria: We enrolled patients with SFA flush occlusion as criteria for angiography. And the clinical inclusion criteria for these lesions were lifestyle-limiting critical limb-threatening ischemia (CLTI), corresponding to Rutherford grades 4, 5, and 6.

Exclusion criteria: Patients with underlying causes of lower limb ischemia, such as acute thromboembolism, trauma, or autoimmune diseases; those with CFA lesions; and individuals with contraindications to intravascular procedures, including allergies to contrast agents.

Study end points: We have analyzed intraoperative radiation exposure and the efficacy of the procedure 12 months post-surgery. Primary endpoints such as technical success rate and patency rate were included, while secondary endpoints included limb retention rate and postoperative complications.

Preprocedural work-up and evaluation. We retrospectively analyzed demographic data, body mass index, current and historical medical information, treatment indications, preoperative computed tomography arteriography (CTA), intraoperative and postoperative complications, and follow-up Doppler ultrasound (ABI) records. Imaging assessments revealed arteriosclerosis and occlusion in the lower extremities, accompanied by symptoms of lower extremity arterial ischemia, thus meeting the diagnostic criteria of CLTI [4]. Preoperative CTA and intraoperative digital subtraction angiography (DSA) were employed to guide the selection of surgical techniques, as well as balloon and stent choices. Clinical and limb threat stages were assessed using the Rutherford classification, GLASS, and the wound, ischemia, and foot infection (WIfi) grading system.

The study adhered to the Society for Vascular Surgery (SVS) guidelines for defining and reporting outcomes related to technical success, primary, assisted, and secondary patency, as well as stenosis/restenosis. One month following surgery, the patient underwent an Ankle-Brachial Index (ABI) assessment at the vascular surgery clinic, with subsequent outpatient evaluations scheduled every 3 months. All examinations were conducted independently by a consistent vascular technician within the vascular surgery examination room and were subsequently reviewed by the vascular surgery outpatient physician.

Data analysis was performed utilizing SPSS version 26.0 software (Chicago, IL, USA). Continuous variables are presented as mean ± standard deviation or quartiles, while categorical variables are expressed as frequencies and percentages.

Endovascular procedures: All procedures were performed under local anesthesia, with the puncture site infiltrated with 2% lidocaine. In a supine position, the patient utilized a micro-puncture system to puncture the CFA against the femoral head, ensuring that the skin puncture point was slightly higher than the artery puncture point to facilitate the tunneling of the sheath under the skin. The needle was inserted into the middle and upper segment of the CFA. Following a successful puncture, its position in the CFA is confirmed via angiography and the guide wire was then advanced into the DFA. The 6F Termel vascular sheath was chosen, and a central point was identified on the sheath wall opposite the side arm opening to facilitate a circular fenestration incision using a scalpel, with a diameter of approximately 2 mm (Fig. 1). The selection of a 2 mm diameter is justified by the fact that the sheath itself measures approximately 2 mm in diameter. This dimension ensures that any instrument passing through the sheath can also traverse the window, while exceeding 2 mm in diameter heightens the risk of sheath rupture. The vascular sheath was then advanced along the guide wire. The position of the fenestration was adjusted to align with the openning of the SFA under preoperative CTA guidance, based on the location of the sheath’s side arm. A VER catheter and a 1.5-m hydrophilic-coated guide wire were utilized through the window to access the superficial artery opening and address the occluded vascular segment. At this stage, the VSF was completed. In cases the SFA orifice is difficult to visualize or the subintimal space is entered, the retrograde puncture technique can be used to place the guidewire retrogradely through the distal outflow tract (femoro-popliteal or infrapopliteal artery) to the SFA opening, providing precise positioning for the catheter and guide wire selected for passage through the fenestration and re-enter the true lumen. Subsequent treatment is tailored to the patient’s specific lesions, potentially involving a drug-coated balloon with or without stent placement (Fig. 2).

The figure shows an example of vascular sheath fenestration, and the arrow points to the fenestration

Procedure images: a The angiography showed that the SFA flush occlusion, the vascular sheath was placed in the DFA, and the DFA indicated by the arrow was severely narrow. b Long superficial femoral artery occlusion. c Angiography showed segmental occlusion of the anterior tibial artery and posterior tibial artery. d The angiography of the inferior malleolar artery was well. e As shown in the schematic, the arrow points to the fenestration of the vascular sheath, which is placed in the deep femoral artery at this time. Adjust the direction of the fenestration according to the position of the sheath side arm and preoperative CTA so that it is directly opposite the opening of the superficial femoral artery. f The catheter followed by the guide wire selected the SFA. g Used a balloon to dilate the SFA. h A stent was placed in the SFA, and a balloon was used to dilate the DFA stenosis. i The SFA and DFA were well showed after treatment. j The anterior tibial artery and posterior tibial artery showed well after treatment

Postprocedural. Aspirin plus clopidogrel (DAPT) is frequently employed for 6 months after interventions. Postoperative follow-up assessments were conducted at 1, 3, 6, and 12 months, or when patients reported a recurrence of symptoms or clinical signs. The clinical evaluation encompassed the assessment of improvements in symptoms of resting pain, alterations in the ABI, ulcer wound healing, and limb preservation. Vascular patency or the presence of restenosis/occlusion was evaluated based on clinical symptoms and ABI measurements. In cases where clinical symptoms and ABI data indicated potential restenosis or re-occlusion, a computed tomography angiography (CTA) was performed to further assess the patient’s condition.

Flush occlusion. Flush occlusion is a chronic occlusion that starts at or less than 1 cm distal to the origin of the artery by visual estimation [5].

Technical success: Restoration of continuous pulsatile blood flow from the groin to the foot was achieved, with residual stenosis maintained at less than 30% throughout.

Clinical success: Clinical symptoms were either alleviated or resolved completely.

Primary patency. No instances of stenosis exceeding 30% or occlusion were observed in the target vessels.

Assisted primary patency: In cases where the target vessel was not occluded, surgical intervention was undertaken to enhance blood-flow patency.

Secondary patency: When target vessel occlusion occurred, surgical intervention was performed to re-establish blood-flow patency.