INTRODUCTION

The arterial access site chosen for PCI can have an important influence on procedural costs and procedural related morbidity and mortality.¹ Access site complications can cause major disability and death. With the exponential rise in PCI procedures and the use of multiple potent antiplatelet agents as standard practice, containing access site complications is an important clinical challenge. Until the late 1980s, most cardiologists utilised the femoral or brachial artery as their access site of choice. The femoral artery has been the preferred route of access ever since the percutaneous Seldinger technique superseded the more technically challenging brachial cut-down approach. There are, however, well documented vascular access complications with the femoral approach especially with concurrent use of glycoprotein (GP) IIb/IIIa inhibitors.² It has, therefore, become increasingly apparent that a safer route of arterial access would be highly desirable.¹

The radial artery has been widely used for many years for haemodynamic monitoring with a low risk of significant neurovascular complications. Two important anatomical features contribute to reducing the risk profile of this access site. First, the vessel is superficial and, in the majority of patients, is not an end artery. Radial artery occlusion does not, therefore, result in major ischaemic complications. Haemostasis is easily achieved by pressure over the point of arterial puncture, while any bleeding is easily recognised allowing prompt action. Second, no major veins or nerves lie close to the radial artery, limiting the risk of neurological damage or arterio-venous fistula formation. The development of small calibre diagnostic catheters facilitated the use of the radial artery for coronary angiography, first described by Campeau in 1989.³ The success of these diagnostic cardiac procedures has led other cardiologists to explore the use of the radial artery as an access site for PCI.⁴

A COMPARISON OF ARTERIAL ACCESS SITES FOR CORONARY INTERVENTION

When a surgical cut down approach to the brachial artery is employed for cardiac procedures, operator skill and experience are important factors in limiting the rate of complications associated with this technically demanding approach. Skilled high volume operators can achieve low complication rates even in the setting of intensive antithrombotic therapy.⁵ For less skilled or infrequent operators, most series consistently reported a 5–10% incidence of major complications^1,6–11 (Fig. 5.1). Major neurovascular complications resulting in acute arm ischaemia or median nerve palsy occur in around 5% of patients (Fig. 5.2). An alternative method to this approach employs a percutaneous Seldinger technique to position a sheath in the brachial artery. This technique is technically much simpler than a surgical cut down, but is associated with a similar risk of important neurovascular complications.¹¹ Because of these issues brachial access is now rarely employed.

Figure 5.1 Neurovascular complications after Brachial cut-down procedures.

Figure 5.2 Arteriogram in a patient with arm claudication following a PTCA performed via a surgical cut down approach to the brachial artery. There is total occlusion of the brachial artery at the level of the antecubital fossa with collateral formation limiting forearm ischaemia at rest.

Following the introduction of the Seldinger technique, the percutaneous femoral approach revolutionized the practice of invasive cardiology and remains the access of choice in many institutions.¹² The femoral approach facilitates rapid and simple access to the left side of the heart and usually facilitates good catheter support as well as access to large-diameter devices. Such advantages are partially offset by bleeding complications, often mandating prolonged bed rest and further treatment (including compression or thrombin injection for a pseudoaneurysm, blood transfusion or surgical intervention) (Figs. 5.3 and 5.4). These can lead to further discomfort and a longer hospital stay, consuming additional institutional resources. In a minority of patients femoral vascular complications can be severe and lead to death. The incidence of significant neurovascular complications ranges from 1% following a simple diagnostic procedure to 17% when large bore catheters are employed in association with aggressive antithrombotic therapy in PCI (Fig. 5.5).^1,13–17 Concealed retroperitoneal bleeding, although uncommon, is an ominous complication that has a reported mortality rate of 15%.¹⁸ One-third of patients who sustain an iatrogenic femoral nerve injury related to a cardiac procedure have a permanent neurological deficit.¹⁹ These problems have not been resolved with the use of vascular closure device. A meta-analysis of 30 randomised trials (with a total sample size of 4000 patients) indicated that vascular closure device increases the risk of femoral access site complications compared to manual compression.²⁰ In addition to these complications, access via a brachial or femoral access site is impossible in 5–10% of patients, due to anatomical variation, peripheral vascular disease or obesity, and the radial access site may allow such patients to be investigated and treated.²¹

Figure 5.3 A-B-C-D Large femoral haematoma.

Figure 5.4 Surgical repair of femoral pseudoaneurysm with large haematoma.

Figure 5.5 Femoral access site complications in current practice.

Multiple studies have compared the radial approach with femoral or brachial access. The best know study, The Access Trial²² examined the relative merits of the percutaneous brachial, femoral and radial access sites in 900 patients undergoing elective PCI. It demonstrates that the radial approach is the safest, with no significant vascular complications occurring, compared to rates of 2% in the femoral group and 2.3% in the brachial group. There was no increase in total procedure duration or radiation exposure when transradial procedures were compared with percutaneous femoral procedures. A recent meta-analysis of 12 randomized control trials further confirmed that the transradial approach is a highly safe technique with comparable procedural duration, radiation exposure and clinical results to that of the transfemoral approach.²³ More importantly, vascular access site complications are virtually abolished (0.3%) by the transradial approach.

Given the demonstrated reduction in the risk of vascular complications, the radial artery is a particularly attractive option in the setting of anticoagulation, post thrombolysis or aggressive antiplatelet therapy. Hildick-Smith et al reported low rate of radial access complications in fully anticoagulated patients with INR >2 who had a transradial coronary angiography.²⁴ In a comparison of vascular access site complications in patients undergoing PCI with adjunctive intravenous GP IIbIIIa inhibitor therapy, 7.4% of the transfemoral patients had a major vascular access site complication (despite the use of weight adjusted heparin, small calibre guiding catheters and femoral artery closure devices in the majority of these patients), compared to none of the similarly treated radial patients.²⁵ In the setting of rescue PCI with adjunct GP IIbIIIa inhibitor, the reported rate of major femoral vascular complications ranges from 20–39%^2,26–28 and around 10% even if vascular closure device is employed.²⁹ Emerging data assessing the efficacy of transradial PCI in such a setting have all reported near complete elimination of vascular complications and with comparable procedural success rate as transfemoral approach.³⁰

Patient comfort and preference are also important considerations in the comparison of these access sites. Delayed mobilisation after transfemoral procedures is common, due to inguinal pain, while bed rest itself has been shown to have an adverse effect on outcome.^31,32 Patients undergoing elective transradial PCI can be mobilised immediately after the completion of these procedures with no adverse effects or risks, which allows PCI to be performed on a day case basis.^33,34 Coronary angiography via the radial artery as opposed to the femoral artery is associated with short-term improvements in quality of life, whilst at the same time reducing hospital costs.^1,35,36 The radial approach for intervention was preferred by 73% of patients in whom preceding diagnostic films were performed by the femoral route.⁴ As a result of the shorter hospital stay and reduced complication rates associated with transradial procedures, hospital costs of coronary stent deployment can be reduced by 15% when compared with the femoral route.³⁶ The transradial technique, therefore, fulfils the requirements for a safer access site for interventional procedures with the added advantages of cost savings and improved quality of life.

THE TRANSRADIAL APPROACH