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The low mortality and perioperative infarction rates for aortocoronary bypass (ACB) make them unsuitable for evaluating the adequacy of myocardial protection. Enzymatic and functional measurements were found to be sensitive and specific indicators of myocardial injury. A prospective concurrent study of 78 patients undergoing triple ACB was conducted to evaluate the effectiveness of three popular methods of myocardial protection. Group I (32 patients) had a single dose of cold (4 degrees C) potassium cardioplegic (CPC) solution infused inducing a mean myocardial temperature (MMT) of 31 +/- 4 degrees C/min. Group II (23 patients) had multiple doses of CPC solution 8nducing a MMT of 22 +/- 2 degrees C/min. Group III (23 patients) had intermittent anoxic arrest at a MMT of 28 +/- 1 degrees C. The groups were not randomized but had comparable clinical symptoms and catheterization findings. Serial measurements of cardiac specific creatine kinase (CK-MB) revealed a peak in enzymatic activity occurring 60 minutes following ACB. The highest CK-MB was significantly (P less than 0.01) lower in group II (25 +/- 8 IU/liter) than group I (50 +/- 8 IU/liter), or group III (68 +/- 14 IU/liter). Myocardial performance was evaluated after ACB by serially measuring left ventricular stroke work index (SW) and left atrial pressure (LAP) in response to volume loading. The rise in SW was significantly (P less than 0.01) greater in group II (3.0 +/- 0.7 gm.m/sq m/mm Hg) than in group I (1.4 +/- 0.7) or group III (1.8 +/- 0.9). The highest SW attained was higher (P less than .01) in group II (43 +/- 7 gm.m/sq m) than group I (19 +/- 6) or group III (34 +/- 8) at comparable LAP values (group I: 20 +/- 5 mm Hg; group II: 18 +/- 3; group III: 18 +/- 4). Post-operative clinical evaluation failed to differentiate among the three groups. The more sensitive indices, however, demonstrated the superiority of cold, multidose cardioplegia in providing optimal myocardial protection.

A total of 130 axillofemoral grafts were peformed in 120 patients from 1966 to present; 66 were axillobilateral femoral moral and 64 were axillounilateral femoral grafts. The average patient age was 66 years. The indications for operation were occlusive disease with rest pain or gangrene in 102 patients, severe claudication four, and bypass of a thoracic aneurysm in one. The one month operative mortality rate was 8 percent (ten patients). Four deaths occurred in elderly patients operated upon as emergencies with acute aortic occlusion. In the 126 elective cases, there were six postoperative deaths (4.7 percent). Twenty thrombectomies were performed in 15 axillobilateral femoral grafts of which 15 (75 percent) were successful. In the unilateral grafts there were 25 thrombectomies in 22 grafts, of which only eight (32 percent) were successful. The 5 year patency rate by the life-table method was 74 percent for axillobilateral femoral grafts and 37 percent for axillounilateral femoral grafts. This difference in patency rates is statistically significant (p0.01). Average flow measured by electromagnetic flow meter in six axillobilateral femoral grafts was 621 c.c. per minute and in 11 unilateral femoral grafts was 273 c.c. per minute. We attribute the higher patency rate in axillobilateral femoral grafts to this increased flow. These data indicate that axillobilateral femoral grafts may be performed with anticipation of a 5 year patency rate comparable to that with conventional aortoiliac reconstruction and that axillobilateral femoral grafts should be performed in preference to axillounilateral femoral grafts in poor-risk patients requiring extra-anatomic bypass for aortoiliac occlusive disease.

Twenty-two matched coronary bypass surgery (CABS) patients were randomly divided into two groups; 11 patients in the control group received CPD-stored or fresh blood (mean age, 5.5 days) containing 70 percent of normal 2-3 diphosphoglycerate (2-3 DPG) and 11 patients received 2-3 DPG-enriched previously frozen, washed, concentrated red cells (2-3 DPG 150 percent of normal). Coming off cardiopulmonary bypass, when given a volume load, the high 2-3 DPG patients had a significant increase in cardiac index (2.95 L. per minute vs. 2.18 L. per minute, p smaller than 0.001) at similar filling pressures. At this time body oxygen consumption, in vivo P50, red cell 2-3 DPG, and arterial-venous oxygen content difference were all increased, but P minus vo2 was normal. Improved oxygen delivery occurred without decreasing mixed venous oxygen tension. The results suggest that, with volume loading, function in the heart with coronary artery disease is limited in part by available oxygen. By decreasing oxygen affinity for hemoglobin by altering red blood cells biochemically, myocardial performance can be improved safely.

The saphenous vein (SV) remains the conduit of choice for lower limb revascularization. When SV is unavailable, or unsuitable, two alternative conduits have been employed: gluteraldehydestablized human umbilical vein (HUV) and polytetrafluoroethylene (PTFE). In this study of the 218 patients who underwent lower limb revascularization, 3-year patency of 85 SV graft was 75% compared to 34% for the 66 HUV grafts and 33% for the 67 PFTE grafts. Three factors were found to independently influence patency: the indication for surgery, the site of the distal anastomosis, and the angiographic runoff. The SV group had significantly better patency than either HUV or PFTE in each of these subgroups. No consistent difference between HUV and PTFE was found. A risk score was obtained by assigning a value of 1 to 3 for each of the factors influencing patency--indication: 1 = claudication, 2 = rest pain, 3 = ischemic lesions; site: 1 = above knee (AK), 2 = below knee (BK), 3 = tibial; runoff 1 = good (two or three vessels), 2 = fair (one vessel), 3 = poor (no vessel). Patients with the lowest risk scores (3 to 4) had the best 3-year patency: SV, 78%; HUV, 44%; and PTFE, 48%. Patients with the highest risk scores (7 to 9) had the worst 3-year patency: SV, 68%; HUV, 32%; and PTFE, 28%. SVs had better patency under high- and low-risk conditions and remain the conduit of choice for lower limb revascularization. Both HUV and PTFE have equivalent and acceptable patency when SV is unavailable or unstable.