Currently, EPs represent about a third of hospital admissions for acute coronary syndromes without persistent ST-segment elevation. The EPs are also a subgroup of patients at high risk of complications because of an excess of ischemic and bleeding events.
In these patients, the use of current ACS antithrombotic strategy reduces the risk of periprocedural thrombotic events but is associated with an excess of bleeding with a strong impact on prognosis. For these reasons, a number of data address the target of the treatment strategies in balancing avoiding the event with avoiding excessive bleeding.
It has been demonstrated that bleeding complications during ACS occur in 2–5% of patients;3
in particular, either access site or non-access site bleeding is common after PCI especially when optimal antithrombotic therapy is given.
Recent studies point out that bivalirudin compared to heparin + GPIIb/IIIa inhibitors is associated with an approximately 40% reduction in both non-access site as well as access site bleedings, preserving similar antithrombotic protection if an adequate antiplatelet pre-treatment is provided.4,13,14
Otherwise, TRA, as mentioned, virtually eliminating access site bleeding and vascular complications, may result in a greater reduction in bleeding complications than pharmacological strategies alone, with a possible synergistic effect on prognosis in patients with ACS.
In our center, more than 96% of the annual total procedures are performed by TRA and the annual incidence of vascular complications is about 2.5%, including arteriovenous fistula (0.1%), side branch vessel perforation (0.3%) and acute radial occlusion/thrombosis (2.1%). The improvement in hemostasis care, based on accurate systematic vascular monitoring by nursing staff, has significantly reduced the incidence of vascular complications. During the last two years, when the radial artery has been unsuitable a transulnar approach has been attempted. From January 2010 to January 2011, 26 transulnar PCI were successfully performed.
In order to increase the success rate of the arterial puncture in reducing vascular complications, the artery pulse, the Allen's and the reverse Allen's test are routinely checked and reported by nursing staff before the procedure. This strategy has increased the percentage of successes from wrist catheterization reducing the need for transfemoral shift.
Often the patients with unsuitable TRA are the same as those at higher risk of vascular and/or bleeding complications (i.e.
elderly, obese, female, NSTEMI, rescue PCI after failed thrombolysis).6,7
In these cases, the TUA approach represents the best and safest alternative option when an interventional procedure is required. In our experience, the more frequent reasons for unsuitability or failure of TRA are: i) radial spasm irresponsive to spamolitic cocktail; ii) anatomic variation, e.g.
extreme vascular loop generally accompained by a remnant radial artery irresponsive to wire distension (0.025” or 0.014” hydrophilic wire); iii) hypoplastic radial artery in the context of small artery diameter and/or pulsus absence; iv) radial artery occlusion after a previous transradial PCI.
Among the strategies used in case of transradial approach failure due to radial loop, recently Agostoni et al.15
reported the feasibility and safety of ulnar access when a homolateral radial sheath is put in place in order to evaluate the suitability of the ulnar artery.
TUA is feasible for percutaneous coronary interventions. However, it has a higher access site failure rate in an unselected patient population ranging from 85.2–90.9% according to two different reports.10,11
In particular, the failure rate is strictly correlated with the operator's experience and is generally lower among skilled radialists
. The ulnar artery is deeper and frequently smaller (mean diameter 2.76 ±0.08 mm compared with radial artery 3.11±0.12 mm) with respect to the other forearm artery. Several authors report higher spasm frequency and anatomical anomalies than those reported for TRA. Despite the risk of complications that might be increased in case of a smaller artery with a deeper course, there are no data to confirm this. Indeed, vascular complication occurrence remains low also when the ulnar artery, usually deeper and smaller than the radial artery, is used (from 4.6–5.7%).8,10,11
Different authors report a similar incidence of artery occlusion one day and 30 days after TRA and TUA procedures. Interestingly, asymptomatic access site artery occlusion occurred more frequently after transradial than transulnar procedures at these time points. The effective outer diameter of the sheathless guiding catheter is approximately 1.5 French smaller than the labeled size of the regular guiding catheter. In particular, several authors report a lower rate of arterial spasm and or occlusion facilitating the possible use of adjunctive devices (i.e
IVUS, double balloon for bifurcation treatment, distal protection devices, thrombectomy catheters, covered stent) usually limited when a standard 5 French or 6 French regular guiding catheter are used. Use of the 6.5 French or 7.5 French sheathless guide catheter system, which has an outer diameter less than 5 French sheath, as the default system in routine PCI is feasible and gives a high rate of procedural success not only via the radial but also via the ulnar artery,12
as confirmed from our experience.
There is virtually no occurrence of ischemic complications after transulnar coronary procedures if the assessment of the integrity of the deep palmar arch by the reverse Allen's test is checked. In fact, the presence of a complete deep palmar arch in approximately 95% of the population, as well as the great capacity of the collateral circulation of the hand, might justify these findings. The rate of asymptomatic occlusion of the ulnar artery was 3% without any ischemic complication. Although some authors believe that the performance of the Allen's test is not necessary when using TUA,15,16
this test is important for unskilled transradial operators in order to reduce complications and increase the success rate of the procedure.