Femoral Artery Puncture Techniques
Optimal location of the anatomical puncture site is the most crucial factor in minimising arterial complication rates. Arteriotomy positions below the common femoral artery (CFA) bifurcation or above the origin of the inferior epigastric artery (IEA) are associated with significant vascular complications.9 There is marked variability in inter-individual anatomy and surface landmarks may not reflect optimal puncture position. Traditionally, the inguinal ligament was used as a suitable landmark because it acts as a surrogate marker for the IEA and retroperitoneum.10
The ‘ideal’ anatomical puncture site is over the mid-portion femoral head, above the CFA bifurcation and below the inguinal ligament.11 Pitta et al. cited vascular complication rates of 18 % when punctures were performed outside of these anatomical landmarks.9 In particular, arterial cannulation above the inguinal ligament (and above the inferior epigastric artery) increases the risk of retroperitoneal haemorrhage due to a lack of ability to compress the femoral artery using the femoral head.12 There are three commonly used techniques to gain femoral arterial access: anatomical landmarks, fluoroscopy guided and ultrasound guided punctures. Anatomical landmarks including skin crease location, maximal palpated pulse intensity and bony landmarks are not reliable methods.10
Fluoroscopy-guided Femoral Punctures
Fluoroscopic landmarks have been widely used in every day interventional practice and are described in Figure 2. The clinical benefits of this modality have not been reported in randomised trials. However, use of fluoroscopic-guided femoral arterial access has been demonstrated to reduce bleeding-related complications in female patients.13 In addition, prospective registry data have demonstrated fluoroscopy use prior to arterial puncture was associated with a lower incidence of pseudoaneuryms (0.3 % vs. 1.15 %, p=0.017), any arterial injury (0.7 % vs. 1.9 %, p<0.01), and hospitalisation (2.1 days vs. 2.4 days, p<0.01).14 Recent multicentre observational data has also demonstrated an extremely low incidence of vascular-access complications (0.89 %) in CTO PCI cases performed by femoral arterial access (81 % 8F sheaths) using routine fluoroscopic guidance.15
Ultrasound (US) Guided Femoral Arterial Access
The important role of US guided venous cannulation is unquestionable. US guided arterial puncture in interventional cardiology is increasingly being adopted as the method of choice, especially in more complex cases such as CTO PCI. Utilisation of ultrasound-guided femoral access can enable direct visualisation of the CFA bifurcation and identify anterior puncture of the needle through the CFA.11 The success of ultrasound-guided femoral arterial puncture was demonstrated in the Femoral Arterial Access With Ultrasound (FAUST) trial, with a reduced number of puncture attempts, improved first pass success rates, reduced time to successful access and reduced vascular complications.16
Micropuncture Technique
Arterial puncture with a small 21-gauge micropuncture needle with a 0.018-inch guide wire (Cook Medical, Bloomington, USA) theoretically increases the chances of obtaining haemostasis with manual compression if the puncture is in a vein. A single-centre, retrospective study that compared a 21-gauge needle vs. an 18-gauge needle has shown no significant difference in access site complications. Randomised data is therefore needed to determine whether the micropuncture technique can reduce vascular complications.11
Access Site Management
Uncontrolled hypertension has been identified as a risk factor for femoral access complication and optimal blood pressure control should be achieved prior to sheath removal.11 Data on vascular closure devices (VCD) are controversial and have provided mixed results, with early studies reporting increased rates of vascular complications while more contemporary registries have reported less bleeding complications compared to manual haemostasis.11 An appropriately powered randomised trial comparing newer generation VCD (after an appropriate learning curve) and manual haemostasis is needed to determine the preferred strategy for obtaining haemostasis. Minimising sheath dwell time may also improve outcomes. Early arterial sheath removal after PCI has been associated with reduced bleeding complications.17