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When Dr Mason Sones made the first major advance in interventional cardiology over 50 years ago with the advent of ‘selective coronary angiography’, 1 it is unlikely that he or others could have imagined its future pivotal role in the current revascularisation era, or perhaps the era itself! Then, selective coronary angiography quickly became a widespread and indispensible tool in the diagnosis of symptomatic obstructive coronary artery disease, and it was not long before alternatives to coronary artery bypass surgery emerged. Dotter and Judkins2 first introduced the concept of ‘recanalisation of arterio-sclerotic obstructions’ with the use of an intraluminal catheter, and Andreas Gruntzig took one giant step further in 1974 when he developed double lumen catheters with expansive qualities and demonstrated their utilisation in the dilatation of arterial obstruction in animal models. In Zurich in 1977 his first ischaemic patient underwent coronary reperfusion by the use of percutaneous transluminal coronary angioplasty.3
‘Dr Andreas Gruntzig and his colleagues are to be congratulated… [He] provides evidence that… balloon angioplasty can effectively dilate highly stenotic coronary vessels and provide immediate improvement in coronary perfusion.’4
Urgent reperfusion for acute myocardial infarction (MI) is now commonplace with primary percutaneous coronary intervention (PPCI) being the treatment of choice in ST-segment elevation MI5. PPCI reduces mortality and decreases the rate of stroke and re-infarction; timing is important in this reduction.6 As well as a reduction in reperfusion time, we strive to achieve procedural success without complications. In percutaneous coronary intervention (PCI), but PPCI in particular, bleeding is a major complication as it can limit our ability to administer antithrombotic agents. Bleeding is an independent risk factor, increasing mortality and ischaemia in patients who undergo PCI7 8 and in those with acute coronary syndromes.9 The mechanisms by which the two are interrelated have been postulated as being caused by the pro-thrombotic state on activation of the clotting cascade in relation to bleeding, cessation of antithrombotic therapies in blood loss and consequences of blood transfusion.10 As the majority of bleeding complications occur at the vascular access site, there is hope that such complications will be reduced by newer antithrombotic agents and vascular closure devices.11
The radial artery has been proposed as an alternative access site and a possible solution to this problem as bleeding complications would seem less.12–14 Radial access first surfaced in 1948 in a study published by Radner 15 but did not make a major appearance until the early 1990s when the ACCESS study looked at a population of 600 patients, investigated between 1993 and 1995 comparing radial, brachial and femoral access for coronary angiography. It demonstrated the superiority of radial access with regard to the access site complications of major and minor bleeding.16 The emerging popularity of radial access and its apparent safety arise from the radial artery's anatomical position; its superficial course provides easy compressibility and thus haemostasis enabling early patient mobilisation with a reduced length of hospital stay post-procedure of −0.4 days.10 In addition, some population studies have shown a patient preference towards radial access;17 and some cardiologists who have rediscovered the radial approach strongly prefer it and campaign fervently in its favour.
Nonetheless, femoral access has been preferred over access from the arm for more than 20 years, and the radial artery is seen by many experienced interventional cardiologists as the femoral artery's less attractive sibling. Currently, the radial approach is used in less than 10% and 1% of coronary angiography worldwide and the USA, respectively.10
In PPCI, Jolly et al10 recently performed a systematic review and meta-analysis of 23 trials observing the radial versus the femoral approach to coronary angiography and/or percutaneous intervention in unstable angina and acute MI. For the endpoint of major bleeding (drop in haemoglobin >3 g/dl requiring transfusion or needing surgical intervention), 13 (0.05%) of 2390 patients in the radial access group compared with 48 (2.3%) of 2068 patients in the femoral access group (OR 0.27; 95% CI 0.16 to 0.45; p<0.01) had this complication, an absolute reduction of 73%. For the composite endpoint of death, stroke or MI in relation to the choice of access site they found no statistical difference between the two groups from the observational studies: 56 (2.5%) of 2209 patients had events in the radial group compared with 71 (3.8%) of 1874 patients in the femoral group (OR 0.71; 95% CI 0.49 to 1.01; p=0.058). Access site crossover was shown to be significantly higher with a radial approach compared with a femoral, with 150 (5.9%) of 2542 patients in the radial group requiring puncture of another access site compared with 34 (1.4%) of 2460 patients in the femoral group (OR 3.82; 95% CI 2.83 to 5.15; p<0.01).10
Before 1999, the data pointed towards a fivefold increase in access site crossover, but more recent studies have shown this to be threefold as a result of changing techniques and increasing radial expertise; of course, there have been developments in femoral access by the use of vascular closure devices for femoral puncture too, and gone are the days of the ‘ticlopidine leg’!
Vorobcsuk et al18 performed a systematic review and meta-analysis of 12 trials comparing the transradial versus the transfemoral approach in the setting of acute MI; they demonstrated bleeding rates, major adverse cardiac and cerebrovascular events and access site crossover rates comparable with those of Jolly et al.10 Importantly, they found no significant difference in the time to reperfusion between the two groups but found access site failure contributed to longer procedure times.
There has been no large multicentre randomised prospective trial comparing the transradial and the transfemoral approach in the setting of acute MI or in non-urgent diagnostic angiography or PCI. To date there is thus no compelling evidence that the radial access site reduces major adverse cardiac and cerebrovascular events. Recent systematic reviews and meta-analyses of trials in the acute setting of ST-elevation MI (where time is of the essence) have shown radial access to be associated with a 10% crossover rate increasing ‘time to reperfusion’ in the individual case.18 These trials frequently exclude unstable patients in cardiogenic shock requiring intra-aortic balloon pumps, central venous access or temporary pacing as these patients automatically ‘qualify’ for femoral access as it is frequently more convenient and appropriate to use one site. In some circumstances it is not unusual for PPCI patients to arrest on the table necessitating cardiopulmonary resuscitation, and femoral access is simply easier and less fiddly under difficult circumstances, most interventionalists will agree.
There are other factors to consider. Radial artery puncture can only be attempted once, after this we observe the morbidity associated with access site crossover, the need for double site post-procedural care and the risk of early and late radial artery occlusion.16 The radial approach does increase procedure times, not only because of the steep learning curve to this technically more challenging approach but also because of the relatively high incidence of radial artery anomalies.19 Even with equal procedural times there is a significant increase in fluoroscopy time with radial approach PCI and an increase in the irradiation of patient and attending staff must follow.20 Femoral access is, for many, easy to achieve, is easier for training, is not restricted by aberrant radial artery anatomy, allows for mammary bypass grafts from either side, and with an adjacent ‘same site’ venous puncture makes for the convenient acquisition of haemodynamic data when required, still important to clinical decision-making even now when such foundations proposed by Sones and others have been eroded by perhaps premature transfer to modern test technologies. This does not mean of course that the technique should be dismissed as a ‘cardiology fashion/fad’ or as an expression of rebellion in the young against the ‘old ways’. It must be learned and taught as there are certain undeniable advantages in diagnostic angiography and elective PCI, a few hours earlier patient discharge perhaps and as a prefered route in aortic/illiac artery occlusions among them.
However, to our mind, in PPCI, the enthusiasm supporting the transradial approach is not sufficiently justified in evidence to support such a shift to it in practice, or yet to dismiss the femoral route from current training programmes.
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