Authors
Text
CASE REPORT
Roberto J. Cubeddu, M.D., Michael Arrowood, PAC, J. Tift Mann, M.D., F.A.C.C., and Merrie
Gough, R.N.
Wake Heart Center, Raleigh NC, USA
Coronary intervention for disease in the distribution of the left internal mammary bypass grafts is an
increasingly common problem. Traditional femoral access is usually challenging in these cases,
and the left radial approach may have advantages. We present a case in which coronary
angioplasty was unsuccessful from the femoral approach, but coronary stenting was later
successfully performed from the left transradial approach.
INTRODUCTION Due to its superior longevity, the left internal mammary artery bypass graft has
been used in large numbers of patients [1]. Although the graft itself is usually not involved with
arteriosclerosis, progression of disease at the distal anastomosis or within the distal native vessel
may occur over time [2]. Percutaneous coronary intervention can successfully be performed in a
high percentage of these cases with sustained clinical improvement [3-13]. However, when
performed from the femoral approach, the procedure is often difficult and technically challenging.
Left radial access offers an alternative approach as described in the present case.
CASE REPORT A 71 year old white male with a past history of hypertension underwent threevessel coronary bypass surgery in December, 1985. Saphenous vein bypass grafts were placed to
the first diagonal (D1) and obtuse marginal (OM) branches, and a left internal mammary artery
(LIMA) graft was implanted to the left anterior descending artery (LAD). The patient’s postoperative
course was benign and he subsequently returned to a normal lifestyle without symptoms. The
patient was readmitted in 1998 with exertional angina and an abnormal exercise test. Cardiac
catheterization revealed symmetrical left ventricular contraction with a normal ejection fraction.
Coronary arteriography revealed total occlusion of both the native LAD and left circumflex (LCX).
Both saphenous vein grafts were patent. The LIMA was patent but had a 90% stenosis at its
anastomosis to the LAD. PTCA was attempted from the femoral approach using a standard 8
French LIMA guide catheter. Despite multiple attempts, the guidewire or balloon could not be
advanced across the lesion. Both flexible and extrasupport guidewires were used with both over
the wire and fixed balloon catheters. The operator commented on the extreme tortuosity of the
IMA graft as well as poor backup of the standard LIMA guide catheter. Procedure duration was 2
hours with 48 minutes of fluoroscopy time. Medical management was undertaken and the patient
was improved until November, 1999, when he was again seen with increasing angina. A stress
echocardiogram was abnormal with a perfusion defect in the distribution of the LAD. The patient
was given 375 mg of Clopidogrel after the exercise test and arrangements were made for cardiac
catheterization the following day from the left radial approach. Doppler analysis revealed the radial
and ulnar arteries to be patent with intact palmar arch. After premedication with Versed 2 mg
intravenously, left radial artery access was obtained using a 20 gauge arterial needle, a 0.025
straight Terumo guidewire, and a 6 French USCI 12 cm sheath. Three milligrams of verapamil
were injected into the radial artery prior to advancement of the sheath. Cardiac catheterization was
performed using a Cordis MPA2 catheter. Coronary angiography was similar to the previous study
revealing all three bypass grafts to be patent and a 90% stenosis at the distal anastomosis of the
LIMA graft (Fig. 1a and b). After administration of 10,000 units of heparin IV, PTCA was performed
using a 6 French 90 cm left transradial left internal mammary guide catheter (Boston Scientific,
Maple Grove, Minnesota). A 0.014 Mailman coronary guidewire (Boston Scientific) was passed
across the distal LIMA stenosis into the LAD. The lesion was predilated with a 2.5 mm Viva balloon
catheter and inflated to 6 atmospheres. A 2.5 mm Duet stent (8 mm in length) was then advanced
across the lesion and deployed with a 16 atmosphere inflation. Subsequent angiography revealed
full stent expansion without residual narrowing or intimal dissection (Fig. 2). The left radial sheath
was immediate removed and hemostasis attained using a compression device. Procedure duration
was 36 minutes with 15.2 minutes fluoroscopy time. The patient ambulated two hours after the
procedure and remained asymptomatic without access site complications. He was discharged the
following morning on aspirin and 75 mg Clopidogrel a day. Postoperative enzymes remained
normal. The patient is currently totally asymptomatic with a negative postoperative stress
echocardiogram.
DISCUSSION Progression of disease within the distribution of a left internal mammary artery
bypass graft is an increasingly common challenge for the coronary interventionalist. Although
successful in the majority of patients, percutaneous coronary revascularization of the left internal
mammary artery using the transfemoral approach is usually a technically challenging procedure [313]. The case describes successful coronary intervention from the left radial approach after a
previous attempt from the femoral approach had been unsuccessful. Technical difficulties involved
in LIMA intervention from the femoral approach stems from the acute angle between the proximal
subclavian artery and the proximal left internal mammary artery. Thus, guide catheter support is
often poor. In addition, the relatively long length and tortuosity of the LIMA graft make guidewire
manipulation and balloon delivery difficult. These technical considerations magnify the difficult of
coronary stenting and to date only isolated reports have been described in the literature [13-16].
Left radial access offers a more direct approach for LIMA intervention. The distance from the
access site to the origin of the artery is shorter and involves less angulation than the femoral
approach. In the present case, guide catheter support, even with the use of a 6 French catheter,
was excellent and coronary stenting was easily performed. The duration of the ad hoc procedure
as well as fluoroscopy time were both relatively low.It is important to emphasize that the authors
have extensive experience with the transradial approach which has been demonstrated to have a
significant learning curve. In addition, meaningful conclusions regarding the utility of the left radial
approach for LIMA intervention must be based upon a larger study. However, the left radial
approach does offer significant potential advantages over the femoral approach for these
procedures.