Transradial Peripheral Vascular Interventions
John T. Coppola, Damian C. Kurian, Cezar S. Staniloae
Department of Cardiology, St. Vincents Hospital, New York, USA

Introduction:
The first report of a percutaneous transradial approach for coronary angiography appeared in 1989 when Campeau1 reported his results.  Kiemencij et al(1993) described the first transradial approach for coronary stenting in 19932.  Since these initial reports over 20 years ago, multiple studies have compared transfemoral with transradial coronary interventions. They have consistently depicted lower rates of access site complications with the latter.  Rao et al. (2008) reviewed the National Cardiovascular Data Registry from 2004-2007 and found only 1.32% of cases were performed through the radial approach in the United States3.  Procedure success rates were similar, but bleeding complications were significantly lower [Odds Ratio 0.42 (0.31-0.56)], after multivariate adjustment.  Byrne et al (2009) reviewed records of 32,822 patients in British Columbia undergoing cardiac procedures and searched for red cell transfusions after the procedure, not related to cardiac surgery4. They found that transfused patients had a significantly increased 30-day and 1-year mortality.  It is well known that radial access halves the rate of transfusions.

1. Transradial intervention of the iliac artery stenosis
1.1 History
Endovascular intervention of the peripheral arterial tree predates coronary intervention5. Percutaneous transluminal balloon angioplasty of the peripheral arteries has existed for as long as coronary angioplasty. In fact, one of the first five human cases of balloon angioplasty performed by Gruntzig in 1978 was of the iliac artery. Palmaz first reported on the use of stenting of the iliac artery, with good short term results6. Current American College of Cardiology/American Heart Association (ACC/AHA) guidelines7 support endovascular intervention with stenting of most symptomatic iliac stenosis after a trial of medical therapy. However, iliac disease may be less responsive to medical therapy alone compared to superficial femoral artery stenoses8. Surgical revascularization of the iliac stenosis carries a significant morbidity, and should be reserved for patients with low surgical risks, and for lesions not amenable to percutaneous therapy. Symptoms of iliac arterial insufficiency may be atypical for classic lower extremity claudication, in fact some patients present only with lower limb weakness. Exercise ankle-brachial index may be necessary to unmask aortoiliac occlusive disease, as robust collaterals may provide adequate lower extremity perfusion at rest. Our group reported, the first cases of successful unilateral or bilateral transradial iliac angioplasty with stenting9,10. (Figure 1, 2)

Figure 1: Selective bilateral iliac artery angiogram via left radial artery showing severe disease in both common iliac arteries.

Figure 2: Stenting of both common iliac arteries via left radial approach.

1.2 Advantages of transradial approach for iliac angioplasty
The transradial approach is particularly beneficial for patients undergoing peripheral interventions for multiple reasons. First, these patients frequently present with bilateral disease that makes them more susceptible to local vascular complications. Frequently the crossover technique is hampered by severe tortuosity; this situation is particularly difficult when dealing with distal external iliac disease. The close proximity of the stenosis makes ipsilateral approach very difficult for distal external iliac interventions. Secondly, it eliminates compressing the common femoral artery after the procedure, which in the presence of occlusive disease may lead to ischemia or even thrombosis. Third, this approach facilitates same day discharge even in the presence of aggressive anti-thrombotic treatment.

1.3 Anatomical Considerations
For obvious reasons, transradial intervention of the lower extremities, including the iliac arteries, may be more difficult in taller people and those with longer upper extremities, due to limitations of the length of equipment. Using the left versus the right radial artery for access, has the advantage of a shorter distance to the descending aorta and not crossing the aortic arch and cerebral vessels. The left subclavian artery most often directs the angiographer towards the descending aorta, so we usually begin the procedure with a multipurpose catheter and standard 0.035” J-wire. If needed due to tortuosity, or type 3 aortic arch, a soft, angle-tipped hydrophilic 0.035” wire may be used with the aid of an internal mammary artery diagnostic catheter to facilitate entry into the descending aorta. Regardless of the wire used, it is mandatory that its passage is carefully followed with fluoroscopy to its destination in the lower abdominal aorta. Severe complications relating to renal, mesenteric, or even spinal vessels (artery of Adamkiewicz) injury can result from “blind” advancement of the wire into tributaries of the thoracic or abdominal aorta.
We recommend that in most cases, angiography of the aortoiliac system begins with a pigtail “power” injection of the lower abdominal aorta (typical 20 cc over one second in the antero-posterior projection). This initial scout film may help define any aortic aneurysms, collateral vessels, and presence of ostial disease of the common iliac arteries. This initial view may be forgone only in the presence of renal insufficiency with the backup of excellent non-invasive imaging. Selective angiography of each iliac artery may be performed with 5F diagnostic Multipurpose or Judkins-right catheters at standard (100 cm) length or with special longer (125 cm) catheters. Infrainguinal anatomy and internal iliac disease is important to assess not only for the appropriateness of endovascular intervention, but also to assess post-procedure complications.
1.4 Other Technical Considerations
Low-osmolality contrast should be used for peripheral angiography to minimize patient discomfort. Complete angiographic run-off of the treated vessel should be adequately visualized to facilitate assessment of any embolic complications. Oblique views of the iliac arteries, which may be particularly necessary for suspected severe eccentric disease, are easily performed with transradial angiography.
Current stent and balloon platforms of all major manufacturers can be safely accommodated within 6Fr and even in 5Fr diameter sheaths. We typically used a 90 cm or 110 cm sheath, depending on the height of the patient to deliver interventional equipment.
Stenotic lesions may be crossed carefully with 0.035” hydrophilic guidewires and direct translesional gradients can be measured with pullback of a 4F diagnostic end-hole catheter (i.e. Multipurpose). For severe lesions or total occlusions, guide wire passage may be facilitated with use of microcatheters and/or 0.014” guide wires, and then exchanged back to the 0.035” diameter wire to facilitate delivery of balloon and stent platforms. We routinely used long (300 cm) 0.035” wires for this exchange.

1.5 Limitations and Complications
There are significant limitations to this technique, particularly related to lack of adequate equipment. The current introducer sheaths extend to a maximum of 110 cm; in some cases of very tall patients, this may bring the tip of the sheath to the abdominal aorta alone and not allow for selective engagement of the iliac artery.  Sheaths of up to 125 cm in length would be required to allow performance of selective angiography as well as provide adequate guidance during the intervention in these particular patients. This implies availability of exchange wires of at least 300 cm and balloon and stent shafts of at least 150 cm. Although there are current limitations to this technique, the potential benefits outlined above should justify development of specific devices designed for this purpose.   
2. Transradial approach to subclavian artery stenting
Atherosclerotic subclavian artery stenosis is a recognized cause of various symptoms as dizziness, myocardial ischemia, or upper extremity claudications or even embolic events11-13. The traditional revascularization method for subclavian artery obstruction was surgical bypass14. Over the last years, the balloon angioplasty and stenting of the subclavian artery became the established therapy, and current recommendations suggest the endovascular approach as first line therapy for patients with symptomatic subclavian artery stenoses.

Figure 3: Selective angiogram via left radial artery showing total occlusion of the left subclavian artery.

Figure 4: Stenting of the left subclavian artery via the left radial artery.

Figure 5: Crosser device at the occlusion site in the left subclavian artery.

The major advantages of the radial approach are particularly relevant when facing totally occluded subclavian arteries. In these situations the support offered by the radial access is significantly better than using the femoral approach. In our experience, once radial access is achieved, the success of subclavian artery angioplasty is close to 100%.

3. Transradial interventions for renal artery stenosis
Renal artery disease is a common form of peripheral vascular disease seen in 6.8% of the population above age of 65 years15. It is more common in patients with coronary artery disease or documented carotid or lower extremity disease, and coexisting hypertension16,17.
Majority of patients with renal stenosis are asymptomatic but some develop renal vascular hypertension.  Hypertension and renal atherosclerotic disease will often co-exist.  It is often impossible to predict the contribution of renal stenosis to hypertension.
Clinical findings suggesting contribution of renal lesion to hypertension include- new onset of hypertension in a patient over 65 years of age, worsening of hypertension in patients with prior good control, rise in creatinine after starting angiotensin converting enzyme inhibitors or angiotensin receptor blockers, flash pulmonary edema, and hypertension with a unilaterally small kidney18.
Currently the AHA/ACC clinical guidelines recommend intervention in hemodynamically significant renal artery stenosis in patients with: accelerated hypertension, resistant hypertension defined as therapy with 3 drugs one of which is a diuretic, malignant hypertension, hypertension with a unilateral small kidney or intolerance to medication7. Patients with flash pulmonary edema and renal stenosis, and the absence of any other etiology for heart failure are the only group with a class Ia recommendation for intervention. Renal intervention to preserve renal function is very controversial and currently is a class IIa recommendation in patients with progressive dysfunction and bilateral disease or disease in an artery to a solitary kidney.
Catheterization based treatment for renal artery disease involves stenting, since balloon angioplasty results have been suboptimal19. Renal atherosclerotic lesions are aorto-ostial lesions with high rates of recurring re-stenosis after balloon dilation.  Patients undergoing renal stenting are usually pre-treated with aspirin, and heparin is used during the procedure. Despite the lack of randomized data, most interventionists will use clopidogrel for 4-6 weeks after stenting. 
With the superior safety profile of the radial approach compared to femoral or brachial access for coronary interventions20, many interventionists extrapolate this benefit to renal interventions21,22. An attractive benefit of performing renal interventions from the upper extremity is that the majority of renal arteries are oriented in a superior direction making co-axial cannulation easier from the upper extremity.  We have found that radial approach offers several other benefits. Generally, patients undergoing renal intervention are hypertensive, making hemostasis after the procedure more difficult; using radial artery eliminates this problem23.
We have found that in elderly hypertensive patients, abdominal aorta is often very tortuous making selective co-axial cannulation very difficult from the groin (Figure 6) but straight forward from the arm (Figure 7).  In addition, the presence of an abdominal aortic stent graft (Figure 8) makes cannulation of the renal artery difficult from the femoral approach.
We normally use the left radial artery for all of our peripheral procedures since this eliminates the need to cross the aortic arch and extends the distance the catheter will reach in the distal aorta.
With the use of the left radial artery, the renal arteries are reached in patients up to 190 cm tall with standard cardiac guiding catheters of 100 cm length. In the majority of cases, we have found the Judkins Right to be an ideally shaped catheter; if the renal artery is extremely up-looking then a multipurpose catheter may serve better.A 6Fr guiding catheter is of sufficient internal diameter to allow for a 6 mm diameter balloon expandable stent passing.  At the head of the first lumbar disk, the 0.035” guide wire is removed and the catheter is vigorously aspirated prior to cannulation of the renal artery. It is of importance to be able to identify the ostium of the renal artery; as a general rule, a shallow left anterior oblique (LAO) 10-200, will often show both

Figure 6: Difficult access to the left renal artery via transfemoral approach

Figure 7: Approach to the right renal artery from the left radial artery.

Figure 8: Renal artery stenting via the left radial approach in a patient with prior abdomonial aortic stent graft.

ostia.  Once the control angiogram is performed, a standard coronary guide wire is used to cross the lesion. We avoid hydrophilic wires since they have a slightly greater risk of distal wire perforation. Our practice is to pre-dilate all lesions; this helps with sizing, judging the position of the ostium and the character of the renal plaques. After pre-dilation, an appropriate sized stent is chosen. We try to avoid over dilation or very high-pressure deployment. If the patient complains of back pain the balloon is deflated immediately and contrast given to check for aorto-ostial damage.

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We have found that engaging the renal artery from the arm provides excellent support; no difficulty has been encounted with stent delivery. At the completion of stenting, a final angiogram is obtained. The catheter is removed over a 0.035’’ guide wire.  Hemostasis is obtained by local compression at the wrist and the patients may be discharged the same day, if after urination there is no hematuria, back pain or unexpected problems.

Conclusion:
In conclusion, transradial approach to peripheral vascular interventions offers numerous advantages, beyond the well-established lower risk of postoperative bleeding. We strongly support the use of radial artery for interventions in the renal, subclavian, and iliac vascular bed. More advanced support catheters, and larger balloon and stent selections are needed before this field moves on into the superficial femoral artery interventions.

References:
1. Campeau L. Percutaneous radial artery approach for coronary angiography. Cathet Cardiovasc Diagn. 1989; 16(1):3-7.
2. Kiemeneij F, Laarman GJ. Percutaneous transradial artery approach for coronary stent implantation. Cathet Cardiovasc Diagn. 1993; 30(2):173-178.
3. Rao SV OF, Wang TY, Roe MT, Brindis R, Rumsfeld J. Trends in the prevalence and outcomes of radial and femoral approaches to percutaneous coronary intervention: a report from the National Cardiovascular Data Registry. JACC Interv. 2008; 1:379-386.
4. Byrne J, Spence MS, Fretz E, Mildenberger R, Chase A, Berry B, et al. Body mass index, periprocedural bleeding, and outcome following percutaneous coronary intervention (from the British Columbia Cardiac Registry). Am J Cardiol. 2009; 103(4):507-511.
5. Dotter CT, Judkins MP. Transluminal Treatment of Arteriosclerotic Obstruction. Description of a New Technic and a Preliminary Report of Its Application. Circulation. 1964; 30:654-670.
6. Palmaz JC, Laborde JC, Rivera FJ, Encarnacion CE, Lutz JD, Moss JG. Stenting of the iliac arteries with the Palmaz stent: experience from a multicenter trial. Cardiovasc Intervent Radiol. 1992; 15(5):291-297.
7. Hirsch AT, Haskal ZJ, Hertzer NR, Bakal CW, Creager MA, Halperin JL, et al. ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Associations for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (writing committee to develop guidelines for the management of patients with peripheral arterial disease)--summary of recommendations. J Vasc Interv Radiol. 2006; 17(9):1383-1397; quiz 98.