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During the interval 1972 to 1977, of 1,522 patients undergoing isolated coronary artery bypass grafting (CABG), 1,459 received grafts to the left anterior descending coronary artery (LAD). Internal mammary artery (IMA) was used in 765 patients and reversed saphenous vein graft (SVG) in 694 patients. Choice of bypass graft was nonrandom. Clinical follow-up is available in 98% of patients. Angiography has been obtained in 69% of eligible patients at 1 month, 65% at 1 year, 62% at 3 years, and 63% at 5 years. There was no difference in operative mortality rates (IMA 1.4%, SVG 1.9%) or 5 year actuarial survival rates (IMA 87.6%, SVG 88.7%). Graft flows were consistently higher at operation with the SVG, but patency rates at each interval were significantly higher with the IMA. Perioperative and late myocardial infarction occurred significantly less often in IMA patients. Superiority in IMA graft patency became apparent after an initial "learning curve" of 2 years of experience. Maintenance and/or restoration of normal left ventricular function was more common in IMA patients operated upon after the initial 2 year experience. IMA grafts are recommended for LAD bypass when the LAD is 2.0 mm in diameter or less. Early results with sequential SVG to the LAD suggest that this may be a realistic alternative to the IMA and may approach the 1 year IMA graft patency rate of 92.6%.

During 1970 to 1977, among 1,733 patients who underwent isolated coronary bypass grafting, the operative mortality was 2.5 percent. Actuarial 5 year survival is 88.1 percent. At an average follow-up of 46 months (range 13 to 108), 90 percent of patients remain angina-free or with symptomatic improvement. The 5 year survival rate of patients with single vessel coronary artery disease is 97.9 percent. In patients with multivessel disease, operative survival appears to be favorably influenced by the presence of normal preoperative ventricular function. Late survival is significantly better in patients with multivessel disease with normal preoperative ventricular function or with complete revascularization. Risk of perioperative myocardial infarction has been appreciably reduced by the introduction of cold potassium chloride cardioplegia. Late myocardial infarction has occurred at an average annual risk of 1.46 percent. These data show that long-term survival and a small incidence of late myocardial infarction after myocardial revascularization are more likely in patients who undergo complete revascularization before significant left ventricular myocardial damage has occurred.

In spite of recent improvements in cardiac surgery, a small percentage of patients have severe postcardiotomy ventricular failure refractory to drugs and the intraaortic balloon. In our experience, the Pierce-Donachy external pneumatic ventricular assist device has proved to be one of the most effective devices for these patients. Since 1981, 30 patients aged 15 to 71 years (mean age, 52 years) with profound cardiogenic shock refractory to conventional therapy after cardiotomy ware supported with the Pierce-Donachy ventricular assist device. Fourteen required left ventricular support, 7 needed right ventricular support with an intraaortic balloon, and 9 had biventricular assistance. Duration of support ranged from three hours to 22 days (mean length, 3.6 days). Seven of the first 11 patients seen died in the operating room of bleeding, biventricular failure, or both. However, 16 patients (53%) had improved cardiac function, 15 (50%) were weaned, and 11 (37%) were discharged. Of the last 19 patients in the series, 47% survived. Factors affecting survival were myocardial infarction (75%) and renal failure (90%). Common complications were bleeding (73%) and biventricular failure (83%).

The success of prophylactic digitalization in reducing the incidence of supraventricular tachyarrhythmias (SVT) was studied in 140 randomly grouped, consecutive patients undergoing myocardial revascularization operations. The test group received either 1 or 1.5 mg. of digoxin the day before operation and were maintained postoperatively on 0.25 mg. of digoxin daily. There was a significant increase (p

The optimal levels of potassium for cardioplegia have been reported to be 13 to 40 mEq/L, although 24 hour preservation of the heart has been achieved with 120 ± 6 mEq/L and Melrose described use of 245 mEq/L. Five groups of six dogs each had 1 hour of myocardial ischemia with a systemic temperature of 27° ± 2° C and a myocardial temperature of 7° ± 2° C (crushed ice) after coronary perfusion with 200 ml of blood (6° ± 2° C at 70 mm Hg) containing various concentrations of potassium chloride: 30 mEq/L (K-30), 60 (K-60), 120 (K-120), or 240 mEq/L (K-240). One group (2K-30) had perfusion with 400 ml of cold blood containing potassium chloride, 30 mEq/L. Baseline studies were repeated after 40 minutes of reperfusion and warming to 37.5° ± 0.5° C. Peak systolic pressure declined in K-60 and K-240 dogs. Indices of myocardial contractility (Vmax, Vce, and dp/dt) declined in K-240 hearts. Left ventricular compliance and muscle stiffness did not change. Heart water and coronary vascular resistance were unchanged. Total coronary flow was elevated during reperfusion in K-30 and 2K-30 hearts but was unchanged in the others. Myocardial oxygen consumption was increased throughout reperfusion in K-30 hearts and was depressed during early reperfuson in K-60, K-120, and K-240 hearts. Lactate uptake was reduced during early reperfusion in all groups except 2K-30. Myocardial biopsy specimens revealed a 70% to 82% decline in creatine phosphate with return to control during reperfusion in all groups. Adenosine triphosphate (ATP) did not fall with ischemia but did so with reperfusion in K-60 and K-120 hearts. Ultrastructurally, there was focal myofibrillar injury in all groups. Two lesions, (1) capillary endothelial bleb formation and (2) intracellular vacuolization, were present in K-60, K-120, and K-240 hearts but were not progressive. The relative lack of injury related to increasing potassium concentrations is related to the use of profound hypothermia.

This study was undertaken to evaluate revascularization of the right coronary artery with regard to factors that enter into the decision to graft less significant lesions, such as graft flow, graft patency and progression of proximal disease. The results of grafting the right coronary artery were studied in 23 patients with lesions reducing luminal diameter by less than 50 percent (Group 1), 35 patients with luminal narrowing of 50 to 70 percent (Group 2) and 112 patients with greater than 70 percent luminal narrowing (Group 3). At operation there was no significant difference in saphenous vein graft flows among the three groups. Postoperatively the mean follow-up period was 20, 27 and 26 months, respectively. Graft patency was not significantly different among the three groups. Progression of the proximal lesion was studied and compared with that in 71 ungrafted right coronary arteries, 60 with less than 50 percent stenosis and 11 with more than 50 percent stenosis. Among vessels with less than 50 percent narrowing, the proximal lesion showed progression in 26 percent of the ungrafted vessels and in 83 percent of the grafted vessels (P less than 0.005); progression to total occlusion occurred in 3 percent of the former and in 28 percent of the latter (P less than 0.005). Progression to total occlusion was more frequently associated with a patent than with an occluded graft (P less than 0.05). The occurrence of significant progression in ungrafted vessels and the lack of effect on graft patency of the severity of the proximal disease suggest that revascularization of less significant lesions may be of value. However, the resultant increase in progression of proximal disease makes the patient dependent on the long-term patency of the vein graft.

To clarify the value of serum enzymes in the detection of intraoperative and postoperative myocardial injury associated with coronary artery bypass grafting, we evaluated 70 consecutive patients (151 grafts). We used electrocardiograms and serial determinations of serum levels: serum glutamic oxaloacetic transaminase (SGOT), creatinine phosphokinase (CPK), lactic dehydrogenase (LDH), and LDH isoenzymes on Days zero, 1,3,5, 7, and 10. Patency of all grafts 1 week postoperatively was 92 per cent. Fourteen patients (20 per cent) had ECG evidence of acute myocardial infarction (AMI) or ischemia lasting longer than 48 hours. This incidence of AMI was attendant with no deaths or discernible changes in postoperative ventriculography. LDH-1 (cardiac fraction) was elevated in all patients with myocardial injury. Late elevation of LDH-1 occurred in 2 patients at the time of postoperative catheterization, 1 of whom had negative findings on ECG. Diagnostic correlation was not observed with total LDH, CPK, or SGOT. Predisposing factors to AMI included preinfarction angina (4 of 14 patients), occluded grafts (4 of 14), and a bypass time greater than 120 minutes.

Six instances of aortic aneurysm in children have been observed in the past 15 years. Four children with aortic stenosis and coarctation of the aorta had aneurysmal dilatation of the, ascending aorta, and two children with coarctation of the aorta had ruptured post-stenotic dilatation of the descending aorta. Our observations suggest that aortic aneurysm can be the result of hemodynamic stress, although developmental anomaly of the aorta associated with aortic stenosis or coarctation could be responsible for the development of the aneurysm.

The myocardial protection provided by cardioplegic solution using buffered, isosmotic potassium (30 mEq. per liter) was compared with intermittent cold coronary perfusion for 2 hours of aortic cross-clamping in dogs. The cardioplegic solution (Group CS) or cold blood (Group CB) was infused every 15 minutes through a cooling coil to reduce the perfusate temperature to 5 degrees C. Myocardial function after 30 minutes of reperfusion and rewarming was reduced in Group CB with a significant reduction in peak systolic pressure at a left ventricular (LV) balloon volume of 20 ml. and a significant reduction of dp/dt. In contrast, in Group CS, LV function was unchanged from the base-line period. LV compliance also was significantly reduced in Group CB while being unchanged in Group CS. Myocardial extravascular water content, obtained by dessication, was significantly higher in Group CB than in Group CS, which may explain the reduction in compliance. Electron microscopy showed normal ultrastructure in Group CS but extracellular edema in Group CB. Total coronary blood flow showed a sustained increase during reperfusion in both groups. Oxygen consumption rose with rewarming to base-line levels in both groups, whereas lactate and pyruvate consumption was reduced in both groups, particularly Group CB. Cardioplegic solution thus appears to be superior to the intermittent perfusion of cold blood for myocardial protection. The addition of potassium arrest, by markedly reducing myocardial metabolism, improves the protection afforded by cold blood perfusion alone.

From Feb. 1, 1972, to Jan. 30, 1984, 1,000 patients had isolated coronary bypass with at least one internal mammary artery, and 103 of them had bilateral internal mammary artery grafts. There were 1,395 associated vein grafts and 1,158 internal mammary artery anastomoses, for a total of 2,556 grafts (2.5 per patient). Patients were followed up for 1 to 12 years (mean 6.3 years) and 77 patients were lost to follow-up at a mean of 4.0 years. Operative mortality was 1.4%, with 11 of 14 deaths in the first 240 patients (4.6%) and eight of 14 in the 103 patients with bilateral internal mammary artery grafts. There were 93 late deaths, with an actuarial survival rate of 93% at 5 years and 84% at 10 years. Angina occurred at a mean rate of 6.2% +/- 1.2% per year. Perioperative infarction was detected in 37 patients (3.7%). Late infarction occurred in 75 patients, for a mean rate of 1.5% +/- 0.3% per year. Reoperation (or percutaneous transluminal coronary angioplasty) was necessary in 35 patients, for a mean rate of 0.85% +/- 0.28% per year. Graft patency was assessed by 1,029 follow-up catheterizations in 519 patients. The patency rate of the left internal mammary artery was 96.4% at 1 year, 88.1% at 5 years, and 88.1% at 10 years. That of the right internal mammary artery was 92.8% (p = NS) at 1 year, 84.6% (p = NS) at 5 years, and at 10 years the numbers were too small to be meaningful. Comparison of patency rates for all internal mammary artery grafts with vein grafts gave 1 year graft patency rates of 95.7% versus 93.4% (p less than 0.025), 5 year rates of 87.9% versus 74.0% (p less than 0.001), and 10 year rates of 83.0% versus 41.0% (p less than 0.001). Included in these patency data are 20 free internal mammary artery grafts; 16 were studied (mean 2.3 years) and 12 of these 16 (75%) were patent. Of the 58 sequential internal mammary artery grafts, 18 were studied by catheterization (mean interval 2.0 years); 35 of 36 anastomoses were patent and one end-to-side anastomosis was closed. Morbidity and mortality for patients having internal mammary artery grafting are comparable to those of patients having saphenous vein bypass only. The demonstrated superior patency for internal mammary artery grafts supports the routine use of bilateral internal mammary artery grafting.

Summary Experiments were designed to demonstrate the feasibility of glycerolizing dog kidneys in preparation for attempting frozen preservation of these whole organs. Results revealed that glycerolization could be obtained, but that the major problem lies with the removal of glycerol and the attendant accumulation of edema and subsequent cortical vascular insufficiency. This problem can be partially resolved by perfusions of decreasing concentrations of glycerol in stepwise fashion.

A technique of intraluminal graft placement for the management of acute dissecting aneurysm of the ascending aorta is described. Acute dissecting aortic aneurysm is associated with early death due to intrapericardial rupture or acute aortic insufficiency, and it requires prompt operative intervention. A simple technical approach excludes the intimal tear, obliterates the false lumen proximally and distally, and achieves resuspension of prolapsed aortic cusps which others have shown to be of long-term durability.

TMERE ARE many methods of arterial reconstruction available for the treatment of patients with atherosclerosis of the femoral and popliteal arteries. The more commonly used operations include: 1) semi-closed thromboendarterectomy,l 2) open thromboendarterectomy with venous patch,"' 12 3) autogenous venous bypass grafts,3 1 4) synthetic bypass grafts.5 20 We believe that a continued critical clinical evaluation is necessary to determine which, if any, of these procedures is most beneficial to the patient. An early laboratory experience demonstrated the superiority of autologous tissues over synthetic grafting materials in small arteries.2' 17 Thromboendarterectomies or autogenous venous bypass grafts were, therefore, selected as the operative procedures of choice in this clinic.3 10 The results of 171 consecutive operations were carefully analyzed and form the basis of this report.

Femoropopliteal bypass grafting with reversed saphenous vein was performed in 47 nondiabetic and 27 diabetic extremities. Graft flow was measured with an electromagnetic flow probe before and after injection of 15 mg of papaverine into the graft. Basal flow (nondiabetic, 74 ± 6; diabetic, 76 ± 11 ml/min) was similar in the two groups. Peak flow was significantly higher in the nondiabetic group (217 ± 14 ml/min) than in the diabetic group (169 ± 18 ml/min, P < 0.05), and the outflow tract was significantly better in the nondiabetics (12.2 ± 0.5) than in the diabetics (8.6 ± 0.7, P < 0.001). When flow was related to the quality of the outflow tract, there was no significant difference between nondiabetics and diabetics. Diabetics with occlusive vascular disease have greater involvement of the tibial and peroneal arteries than do nondiabetics. Vascular reactivity is not significantly impaired, and arterial reconstruction should not be withheld on the basis of anteriolar-capillary involvement.

A young woman abruptly developed the return of angina pectoris after a successful coronary bypass graft. Angiography and repeated surgery revealed a proximal occlusion of the vein graft, not related to poor distal run-off. Pathologic examination of the removed vein graft revealed thrombotic occlusion associated with an intimal mycotic abscess.

Seven dogs had telescopic anastomosis of the IMA to the LAD or CCA. Twenty-two to twenty-eight months later all anastomoses were patent, but one was severely stenotic and three were moderately stenotic. Of the six dogs that were studied by right-heart bypass four demonstrated deterioration of LV function with IMA occlusion. Metabolic data were combined from six dogs and revealed changes similar to those observed in normal dogs with occlusion of the LAD, but with a blunted reactive hyperemia response.

Ten canine hearts undergoing perfusion with 200 to 300 ml. of clinical dextran containing 15% DMSO during extracorporeal support maintained the circulation acutely and seven supported life beyond the acute period. The seven long-term survivors maintained their weight, evidenced normal activity, and had unremarkable electrocardiographic tracings. Light microscopy demonstrated a significant myocardial lesion in the surviving heart perfused with the most dextran-DMSO, which may have been related to electrical defibrillation. Electron microscopy revealed no definite abnormalities. Catecholamine content of the myocardium was moderately reduced. Myocardial analysis for electrolytes, fat, carbohydrates, and various glycolytic and citric acid cycle enzymes revealed no major deviations from normal.

The effect of PGA 1 on regional blood flow was studied at the time of arterial reconstruction in 19 aortocoronary grafts, five interval carotid arteries, eight aortofemoral grafts, and seven femoropopliteal grafts with the use of an electromagnetic flow probe. Bolus injections of 25 or 50 μg of PGA 1 were given IV or IA as well as papaverine (15 mg. IV or IA) which was used in evaluating the coronary circulation. PGA 1 (25 μg IA) increased flow in the coronary, femoral, and popliteal vascular beds but to a lesser degree than papaverine (15 mg.). When given IV, PGA 1 increased flow in only the femoral bed while papaverine, which was used in evaluating coronary flow only, resulted in a significant increase in coronary flow.

Summary Single cells and tissue fragments will survive after freezing with dimethyl sulfoxide or glycerol, but organ preservation in the frozen state has not been possible. Evidence that a vascular block occurs on replantation of a frozen, thawed organ has led to a study of the micro-circulation of the autotransplanted canine omentum protected with 15% dimethyl sulfoxide after freezing at −55° to −60°C for 24 hr. The degree of stasis was quantitated on a scale of 1 to 10 during a 3-hr period of observation prior to and immediately following replantation. Nonfrozen, control transplants demonstrated an essentially normal microcirculation. Stasis of 3+, 4+, and 5+ was noted in the frozen replanted omentum. This stasis was reduced to 1+, 1+, and 2+ when the animals were treated with 1 mg per kg of heparin prior to replantation of the omentum. Low molecular weight dextran (1.5 g per kg) was nearly equally effective in preventing stasis. Treatment with standard dextran or mannitol before replantation resulted in 9+ to 10+ stasis, while a combination of heparin and mannitol was effective in preventing this extreme stasis. Diffuse, severe swelling and weeping of the omentum was noted in all the frozen preparations, but was distinctly less in those treated with dextran or mannitol and essentially absent in the nonfrozen controls. It is postulated that the vascular lesion of freezing has two basic components. One is endothelial injury with adherence of the formed circulating elements leading to stasis and presumably thrombosis. Second, there is damage to the vessel with extensive leakage of plasma into the tissues. As the stasis is largely preventable with heparin or low molecular weight dextran, it would appear that edema and swelling, by virtue of compression of the intrinsic vasculature, is the more significant obstacle to organ storage in the frozen state.

Summary Six dogs with implantation of the internal mammary artery into the ischemic anterior left ventricle had patent implants 4 to 9 months later demonstrated by cineangiography. They were then studied as right heart bypass preparations. Occlusion of the implant was not reflected in total coronary flow and did not alter ventricular function except in 1 animal when the heart was maximally stressed. Implant flow averaged 2.2 to 7.6 ml. per minute per 100 Gm. LV and paralleled changes in coronary flow. Control dogs had a fall in total coronary flow and a shift of the ventricular function curve to the right with acute occlusion of the left anterior descending artery. Cineangiographic patency of an internal mammary artery implant is not synonymous with significant implant flow nor does it follow that this flow contributes greatly to ventricular performance.

We report an instance of coronary reconstruction with internal mammary artery (IMA) in which catheterization demonstrated patency at 1 week, loss of patency at 1 year, and return of patency associated with progression of proximal coronary disease at 5 years. Although narrowing or distal occlusion of IMA grafts has long been recognized, and it has been suggested that this is a physiological or reversible phenomenon, this is the first instance in which reversibility has been documented.

Early (one week) and late (one year) postoperative angiography was performed in 142 patients having 310 grafts (117 right coronary artery [RCA], 134 left anterior descending [LAD] and 59 circumflex coronary artery [CCA]) to assess the factors responsible for failure of aorta-coronary artery saphenous vein grafts. Early catheterization revealed an 85.5 per cent patency rate with similar rates for each artery (RCA 88 per cent, LAD 85 per cent, and CCA 81 per cent). At one year 238 grafts remained patent, for a cumulative patency rate of 76.8 per cent with a similar distribution for each vessel (RCA 75 per cent, LAD 78 per cent, and CCA 76 per cent). Intraoperative flow measurements were correlated with early and late patency. Grafts with a basal flow less than 20 ml. per minute have a 42 per cent early closure rate and a 21 per cent late closure rate (cumulative 63 per cent). A basal flow of less than 40 ml. per minute was associated with a 25 per cent early failure and an 11 per cent late failure rate (cumulative 36 per cent). Basal flow at levels greater than 40 ml. per minute was not associated with an increased probability of graft closure. Absence of reactive hyperemia (30 second graft occlusion) was associated with a 19 per cent probability of early closure and a 31 per cent probability of cumulative thrombosis. A papaverine-induced flow increase (15 mg. given into the graft) of less than 100 per cent over basal flow gave a 20 per cent probability of early failure and 30 per cent probability of cumulative closure. Thus intraoperative basal flow measurements are of predictive value in determining the fate of aorta-coronary artery vein bypass grafts, and vasodilatory maneuvers provide little additional information.

The relationship between ice-chip cardioplegia and impaired left diaphragmatic function was evaluated in dogs. Direct or indirect contact of the phrenic nerve with crushed ice for 30 or 60 minutes resulted in phrenic paralysis for 6 to 28 days, with responsiveness returning from 7 to 62 days later. Microscopical examination of injured nerves revealed injury to the myelin sheath and preservation of axons. Paralysis of the left diaphragm after topical cardiac hypothermia may be secondary to cold injury of the phrenic nerve, which is reversible.

The left internal mammary artery (IMA) has been used as a sequential graft to the left anterior descending (LAD) system in 39 patients. Seven patients having operation in 1977 were followed up for 2 years, and cardiac catheterization in four revealed no problems related to the anastomoses. After a 2 year hiatus we resumed use of the procedure in 1980. A total of 10 patients have had catheterization from 1 month to 5 years postoperatively with no anastomotic narrowing or restriction of distal IMA flow by the side-to-side anastomosis. The IMA should be equal to or greater in size than the larger of the two vessels to be grafted. We continue to use this procedure in carefully selected patients.