Safety And Feasibility Of Selective Angiography Of Left InternalMammary Artery Grafts Via Right Transradial Approach
Orazio Valsecchi, AngelinaVassileva.
Interventional Cath. Lab. Cardiovascular Department. Ospedali Riuniti Bergamo Italy

Introduction
Right transradial approach (TRA) for both diagnostic and interventional procedures is becoming common practice in many institutions, but angiography and PCI of left mammary artery by-pass graft (LIMA) via the right radial artery is still technically challenging and has not been well described.
 The aim of the study was angiographic and clinical outcome of consecutive patients undergoing selective diagnostic and/or interventional procedures of controlateral mammary by-pass graft. Internal mammary artery (IMA) grafts are increasingly used for coronary artery bypass surgery because of their durability and longevity compared to saphenous veins1,2. IMA angiography therefore has increasingly been gaining its importance in the assessment of patients for coronary bypass surgery.
Furthermore, some investigators have advocated IMA imaging to be a routine part of diagnostic coronary angiography3,4. Traditionally, canulation of both the left and the right IMA has been done by the transfemoral approach. Since Campeau5 introduced transradial coronary angiography in 1989, the radial artery has been increasingly used as the primary access site for coronary angiography and coronary interventions6, but the technique for left IMA imaging via right radial approach has not been well described7-9.

Materials and Methods:
Study population
From June 2002 to March 2009 246 consecutive patients ( 88.21 % male; age 67.7±7.8 years) (Table 1) with previous CABG underwent selective coronary and LIMA graft angiography via right TRA by a single experienced operator. 180 patients were admitted with stable angina; 66 patients with acute coronary syndrome.

Table 1. Baseline Patients Characteristics

Correspondence: Dr. OrazioValsecchi U.O.DiagnosticaedInterventisticaDipartimentoCardiovascolare Clinico e di Ricerca Ospedali Riuniti di Bergamo Largo Barozzi, 124100 Bergamo Italy
Email: ovalsec@tin.it

Radial Artery Canulation and Angiography
Radial artery canulation was performed with the right arm positioned beside the patient's body while the wrist was hyper-extended. After local anaesthesia with 1 ml of 2% xylocaine and 1 ml of NaHCO3-, the radial artery was punctured with a 20 gauge 1-piece metal needle and a 0.025" straight guidewire was inserted through the needle. Upon removal of the needle, a 23 cm long 6 Fr sheath (Cordis Corporation, Miami, Florida) was placed over the guidewire. To reduce spasm and discomfort, an intra-arterial injection of a drug “cocktail” containing 200 mg of nitroglycerin, 2.5 mg of verapamil, 2 ml of NaHCO3-, and 2 ml of 2% xylocaine was administered through sheath.  Intavenous Heparin 5000 UI was given to prevent early and late radial artery occlusion. Selective coronary angiography was performed with diagnostic 6F catheter Sones type II (Cordis Corporation, Miami, Florida) in 93.08% of patients. Amplatz Left Curve 2  and IMA were used for selective canulation of saphenous vein grafts (SVG).
Selective canulation of LIMA
Subsequently, selective LIMA angiography was performed using diagnostic catheter BC-Bartorelli-Cozzi (Cordis Europe, LJ Roden, The Netherlands), 5.2 F in size ( ID:0.44″) and 100 cm long (Fig. 1). This catheter is recently designed for selective angiography of LIMA grafts via left radial artery. Different from the standard IMA diagnostic catheter, this catheter has an overbent design, with a 180° primary curve, that provides coaxial alignment with the LIMA takeoff angle, and a secondary 90° curve creating  a support segment  on the subclavian artery wall. This catheter has an atraumatic soft tip and flexible distal segment. The BC diagnostic catheter was used successfully in 98% of the patient’s population for right radial approach. In the remaining 2% of the cases, standard IMA (Cordis Corporation, Miami, Florida) diagnostic 6 F catheter was used.

Fig. 1 Diagnostic catheter BC-Bartorelli-Cozzi

After selective coronarography was performed in all the patients, a semiselective angiography Fig.2 was performed in the proximal part of the left subclavian artery to determine the anatomy of the left subclavian artery and the exact position of the subclavian artery  from where the left IMA originated. The semiselective angiography of left subclavian artery was performed in 85 % of cases with Simmons II or III diagnostic catheter; 5% with Judkins Left 3.5 6F and in 10 % of the cases with IMA 6F. Inside this catheter, the hydrophilic guidewire was advanced (Radifocus guidewire M

Terumo, 0.035″, 260 cm, Japan) through the subclavian artery and placed distally in the contralateral left radial artery (Fig. 3). At this point the catheter used to advance the hydrophilic wire was removed over the wire,  a Bartorelli-Cozzi or IMA catheter was advanced  and the catheter tip were canulated into the left IMA by slightly withdrawing the catheter.

Fig. 2Semiselective angiography  in the proximal part of the left subclavian artery

Fig. 3Hhydrophilic wire distally in the contralateral left radial artery

Results: In 98.9% patients, adequate right radial access was obtained.  Semiselective angiography of left subclavian artery was performed in all the cases. Selective angiography of LIMA graft was successfully performed in 89.02% of patients while it failed in 10.97% because of severe tortuosity of brachiocephalic trunk or severe calcified and tortuous left subclavian artery (Fig.4). In 98% of the cases, BC( Bartorelli-Cozzi) 5F diagnostic catheter was used, while in remaining 2%, an IMA 6F  diagnostic catheter was employed. Angiography of LIMA  grafts revealed severe stenosis on the segment of LAD distally to the anastomosis in 13 patients. Ad hoc angioplasty was performed through the LIMA grafts using 6 F IMA guiding catheters (Medtronic (Maple Grove, Minnesota)). Balloon angioplasty was performed in 3 patients while PTCA with stenting was performed in 10 patients, producing good angiographic result. No vascular injuries at the LIMA takeoff were

observed as a result of the selective canulation. There were no procedure related complications such  cerebrovascular events, subclavian artery dissection and arterial thrombo-embolism. No major cardiac events were obesrved. At the end of the procedure haemostasis at the entry site was chivvied within 5 minutes without any vascular complications. Patients were then ambulate immediately. None of the patients evidenced loss of radial pulsation before discharge. Right radial access site is preferred because  80% of the patients with CABG had a left radial artery as a free graft.

Fig. 4Selective angiography of LIMA graft

Discussion
This study demonstrated that the contralateral selective IMA angiography can be performed easily and safely via right transradial approach following a successful coronary angiography .

Transradial LIMA angiography and angioplasty have the advantages of immediate mobilization of the patient and near elimination of puncture site complications, which lead to shorter hospitalization times and significant cost savings5,13. Furthermore, the absence of nerves and veins of significant size near the canulation site can potentially reduce complications such as nerve injury and arteriovenous fistula. Occlusion of the radial artery can happen, but the vast majority of cases remain without clinical sequalae because of the dual blood supply to the hand14.

Conclusions: This present study indicates that in patients with previous CABG the presence of LIMA grafts is not a limitation to successfully perform  diagnostic and interventional procedures via right radial approach with experienced operators.