Download our articles on outcomes from radial artery grafting published in The Annals of Thoracic Surgery and Circulation.
Choice of Bypass Grafts
The choice of conduit used in coronary artery bypass grafting (CABG) has evolved over the years. Initially, the first bypass surgery performed in 1967 utilized saphenous vein harvested from the leg. The saphenous vein has been the workhorse conduit for over 40 years. The major problem, however, with the conduit is that it has a significant failure or occlusion rate. Several recent studies have found an early occlusion rate of 20% at one year after CABG primarily due to intimal hyperplasia or thickening of the vein graft wall due to the arterial pressure effect. (Veins are thin walled delicate vessels designed to exist in the low pressure venous circulation). In addition, the saphenous vein is often much larger than the target coronary artery resulting in a marked caliber mismatch causing graft closure. Late closure is due to vein graft atherosclerosis which results in a 50% to 60% closure rate at 10 years. Thus, the search for alternative conduits focused on arterial options.
Left Internal Thoracic Artery
One of the most important advances in cardiac surgery was the contribution by Floyd Loop and colleagues at the Cleveland Clinic, published in the New England Journal of Medicine in 1986. They showed that using the left internal thoracic artery (harvested from under the sternum) resulted in significantly improved survival of patients compared to those patients having CABG using only saphenous vein. This effect was due to the improved patency rate of 90% of the left internal thoracic artery at 10 years. CABG using the left internal thoracic artery (LITA) and saphenous vein became the accepted and standard surgical approach in patients undergoing bypass surgery.
Radial Artery Conduits
Acar and colleagues in Paris re-introduced the radial artery as a bypass graft in 1989. Their group had previously used the radial artery in the 1973 but had abandoned the conduit due to spasm and graft failure. Acar then found several patients, many on calcium channel blockers, with widely patent radial artery grafts at 15 years. Radial artery grafting was thus re-introduced and gradually adopted by surgeons as an excellent alternative conduit to the saphenous vein. Subsequent patency studies from multiple institutions confirmed excellent 90 % to 95% patency rates at 5 to 10 years. However, there is little data showing the long term survival benefits of radial artery grafting combined with using the LITA during CABG. The following abstract summarizes our 16 year experience with CABG using the LITA and radial artery grafting.
Coronary Artery Bypass Grafting Using the Radial Artery: Clinical Outcomes, Patency, and Need for Reintervention
Robert F Tranbaugh, Darryl M Hoffman, Kamellia Dimitrova, Charles M Geller, Helbert DeCastro, Loren J Harris, Paul Stelzer, Patricia Friedman, Helbert DeCastro, Bertram Cohen. Division of Cardiac Surgery, Beth Israel Medical Center, New York, NY. Circulation. 2012;126:S170-S175
Background: Radial artery (RA) grafts are an attractive second arterial conduit after the left internal thoracic artery (LITA) for coronary artery bypass surgery (CABG). However, long term outcomes and the need for subsequent reintervention have not been defined.
Methods and Results: We performed a retrospective cohort study of our single institution’s 16 year experience with 1,851 consecutive patients (average age 58 years, 82% male, 36% diabetic) undergoing primary, isolated CABG with the LITA, RA and saphenous vein as needed. Average grafts per patient were 3.8 with 2.4 arterial grafts per patient. Survival was determined using the Social Security Death Index. Grafts were nonpatent if they had a >50% stenosis, a string sign or were occluded. Five patients (0.3%) died and 0.8% had a myocardial infarction, 1.1% a stroke and 0.6% renal failure. Kaplan Meier estimated 1, 5, 10 and 15 year survival was 99%, 96%, 89% and 75%. Of the cohort, 278 symptomatic patients underwent cardiac catheterization at our institution an average of 5.0 + 3.8 years (range 0.1 to 12 years) after CABG. Overall RA (n=420 grafts) patency was 82% and SV (n=364 grafts) patency 47% (p<0.0001). LITA (n=287 grafts including 9 sequential grafts) patency was 85% and RITA (n=15 grafts) patency was 80% (p=0.6). RA patency was not different from LITA patency (p=0.3). Overall freedom from catheterization, percutaneous intervention and CABG was 85%, 97%, and 99%.
Conclusions: RA grafting is a highly effective revascularization strategy providing excellent short and long term outcomes with very low rates of reintervention. RA patency is similar to LITA patency and is much better than SV patency. RA grafting should be more widely utilized in patients undergoing CABG.
Our study shows that radial artery grafting results in outstanding short and long term survival. This is one of the lowest reported operative mortality rates after bypass surgery in the literature. Our long term survival is also superb.
Radial Artery Conduits Improve Long-Term Survival After Coronary Artery Bypass Grafting. Tranbaugh RF, Dimitrova KR, Friedman P, Geller CM, Harris LJ, Stelzer P, Cohen B, Hoffman DM. Ann Thoracic Surg 2010; 90:1165-72.
This study compares survival rates in matched patients receiving the LITA and saphenous vein versus a group receiving the LITA, SV and radial artery. This provides a direct comparison of the two conduits. Our hypothesis is that using the radial artery as the second choice conduit during CABG will significantly improve survival compared to those patients receiving a saphenous vein as their second conduit. Both groups have the LITA as the primary conduit to bypass the LAD.
This important study clearly shows the benefits of radial artery grafting compared to saphenous vein grafting. Using the radial artery significantly improves long term survival in a propensity matched group of patients. This is shown in the following graph:
Kaplan Meier survival is significantly improved (p=0.0011) over 14 years in patients receiving LITA, RA, and SV as compared to a matched group of patients receiving LITA and only SV. We also found that use of the radial artery was an independent predictor of survival (HR=0.715, p=0.0084)
Long-Term Survival Benefits
Cardiac Surgeons at Beth Israel Medical Center use multiple arterial conduits (left internal thoracic artery, radial artery, right internal thoracic artery) in 75% of all patients undergoing CABG. This is accomplished with an extremely low risk: an operative mortality of 0.3% and rates of stroke, heart attack and renal failure under 1%. Most importantly, arterial grafting improves long-term survival.
It is also useful to compare our results to a similar cohort of patients undergoing percutaneous interventions (PCI) using stents. We found that CABG using multiple arterial grafts is a much safer option than PCI in patients with multiple blocked arteries. Our data indicated a much improved survival advantage with CABG compared to PCI.
Arterial Grafting at Beth Israel Medical Center
Patients are more likely to receive arterial grafting at Beth Israel than other hospitals in New York State. Only 18% of patients undergoing CABG in NY State receive 2 or more arterial grafts compared to 75% at Beth Israel. In addition, 35% of our patients receive 3 or more arterial grafts, compared to only 2% in NY State.
Experts in Endoscopic Radial Artery Harvesting
Removal of the radial artery from the arm is done using a minimally invasive technique which personnel at Beth Israel Medical Center have pioneered. Using a small "wrist band" incision, the entire radial artery is able to be removed with an excellent cosmetic result. Post-operative pain is much less, with a faster recovery. The endoscopically harvested radial artery is an outstanding conduit for bypass surgery.
The Beth Israel Advantage
- Senior, experienced cardiac surgeons (two at each operation), in a highly specialized, boutique practice dedicated to the surgical patient
- Surgeon-directed model of care using an experienced team of nurse practitioners and physician assistants
- Caring, supportive and experienced critical care and step-down nursing staff
- Arterial grafting with better survival