Dr. Akins, Dr. Lyttle, members and guests. Greetings from Australia.
In addition to the extensive use of the internal thoracic arteries, we have progressively used more single and bilateral radial artery grafts to achieve total arterial revascularization. Specific additional indications have been varicose or stripped veins, obese diabetic patients, and those with severe emphysema precluding bilateral internal thoracic artery use.
To date, we have performed more than 3000 radial artery procedures including more than 500 bilateral radial artery revascularizations in our three institutions. We present our initial experience to June 1, 1997 in 261 consecutive patients having bilateral radial artery grafts for isolated, first time or redo coronary bypass.
1237 patients had a single radial graft; 261, (the study group), had bilateral radial artery grafts; a total of almost 1500 patients. Mean age was 61 years; 68% were male; mean angina class was 2.8; (Canadian Cardiovascular Society Classification). 32% were diabetic including 5% that were insulin dependent; 31% had unstable angina; 52% had prior myocardial infarction; 28% had impaired ventricular function; 12% were having a re-operation. The bilateral group in general had more diabetes and more re-operations.
The Allen's test was always performed. Re-perfusion within 10 seconds was considered satisfactory. The arms were marked pre-operatively. All operative fields were prepared. Arterial monitoring was by the femoral artery and both radial arteries were harvested simultaneously. The incision was contained between the elbow and the wrist creases and followed the medial border of the brachio-radialis. Care was taken to avoid the lateral cutaneous and superficial radial nerves. Usually 20 to 22 cm of radial artery could be harvested together with the adjacent venae comitantes. The radial artery was usually 3 mm in diameter, and the pedicle itself approximately 10 mm in diameter. A no-touch technique was used. The larger branches were divided between clips. A 1% solution of Papaverine and heparinized arterial blood was placed intra-luminally and the radial artery pulsated against its occluded end. The proximal end of the dissection was marked by a venous plexus. Two hemoclips were placed on the radial artery and the artery divided with a 3 mm cuff and stored in 1% Papaverine and heparinized arterial blood. The forearms were closed and bandaged, placed by the sides, and covered and sternotomy performed.
Cardiac protection was with antegrade and retrograde blood cardioplegia at room temperature. Septal myocardial temperature was kept at 25°C. Further retrograde cardioplegia was given after each anastomosis. All anastomoses were constructed during a single period of aortic cross-clamping. A mean of 3.6 distal anastomoses were constructed per patient. 939 anastomoses in total. The mean aortic occlusion time for all proximal and distal anastomoses was 74 minutes.
In addition to the bilateral radial arteries, a further 240 patients, (97%), had either one or bilateral internal thoracic arteries used. Only 30 patients, (5%), had any vein bypass used. In general the ITA was anastomosed to the LAD, the radials to the next most important territory, the generous length allowing distal uncompromised anastomosis beyond any lesion.
Of the 594 anastomosis, from 522 radial artery grafts, the majority, 281 went to the circumflex marginals, and the next greatest number to the posterior descending artery (194). 95% of all patients received arterial grafts only; 98% of all distal anastomosis were constructed with arterial grafts. The proximal anastomosis was constructed to the aorta directly in 472. If aortic atheroma or graft length were a problem, the proximal anastomosis was constructed to the left internal mammary in 42 or to another radial artery in 8.
Nitroglycerine or Milrinone infusions were used routinely for 24 hours then oral calcium channel blockers.
Results:
There were two peri-operative deaths; a peri-operative mortality of 0.8%. The incidence of stroke was 0.8%. Infection requiring treatment with antibiotics or operation 0.8%. Re-operation for bleeding 0.4% (1 patient). Peri-operative infarction 0.8%. The forearm wounds healed well, the slides depicting a typical patient's forearms at 72 hours post-operatively, and just before discharge (5 days). Avoidance of leg incisions allowed early ambulation. There were no forearm infections in 261 patients, no hand ischaemia, but there were four haematomas, one of which required drainage.
Complete functional assessment of the forearms was made in 192 patients by an occupational therapist at 3 months; 10% of patients had sensory loss; 1 patient had interosseous muscle weakness; 33% of patients complained of scar discomfort; 8% said that their performance was affected because of their scar discomfort;
16 patients underwent re-angiography for possible cardiac symptoms at four months post-operatively; 20 of 22 distal radial artery anastomoses, (91%) were patent. There was one string sign and one occlusion.
In general, the radial arteries were smooth and filled the distal circulation well, here (slide) shown to the posterior descending and the left ventricular branch, and here again (slide) running from the aorta right down to the inferior circumflex marginal system. The string sign and the occlusion both occurred in vessels which were large and had less than a 50% stenosis.
We conclude that the use of bilateral radial arteries is safe. It allows uncompromised distal complete revasculization: 95% of patients could achieve total arterial revasculization. There were no major hand problems. We believe that the patency will be good but probably inferior to that of the internal thoracic artery. We are now undertaking an ethics approved routine angiographic study at one year and three years post-operatively to determine the longer term patency of the radial artery grafts.
Thank you.