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Background. Intracoronary stents are being used to treat acute and threatened closure after percutaneous transluminal coronary angioplasty and to prevent restenosis. Methods. The outcomes of 68 patients having coronary artery bypass grafting after stent placement were reviewed. The mean age was 60.5 ± 9.7 years, and 71% were male. Thirty-seven percent had hypertension, 13% had diabetes, 62% had class III or IV angina, 60% had multivessel disease, and 40% had sustained a prior myocardial infarction. Fifty-three patients underwent emergency operation, 22 with hemodynamic collapse immediately after percutaneous transluminal coronary angioplasty, and 7 others required urgent revascularization within 24 hours of angioplasty. Seventeen underwent coronary artery bypass grafting for acute closure of the stented vessel several days after the angioplasty procedure. Results. There was no correlation between urgency of the procedure, previous infarction, or previous coronary artery bypass grafting with successful procedure. The in-hospital mortality was 4.4%, 21% had a Q-wave myocardial infarction, and 1.5% sustained a stroke. Ejection fraction was the only correlate of long-term mortality. Conclusions. Coronary artery injury for which stents are placed for acute or threatened occlusion or to prevent restenosis but then fail, thus necessitating coronary artery bypass grafting, can be treated successfully. Although the rate of Q-wave myocardial infarction is substantial and related to the initial ischemic insult, the long-term survival and event rates are excellent with prompt surgical revascularization.

The effects of cardiomyoplasty were evaluated with multiple-gated equilibrium radionuclide angiocardiography and catheterization in a canine model of chronic heart failure. Doxorubicin was administered to 12 dogs at a dose of 1 mg/kg/wk intravenously for 10 weeks. Left ventricular ejection fraction was reduced from a mean of 53.6% ± 3.4% to 33.5% ± 2.3% preoperatively. Two dogs died of presumed arrhythmia during this period. Cardiomyoplasty with the left latissimus dorsi muscle was performed on 10 dogs. The muscle was wrapped around both the left and right ventricles. Five dogs died of infection or arrhythmia after the operation. Postoperatively the muscle remained unstimulated for 2 weeks to allow adhesion to the heart. After this period, the latissimus dorsi muscle was conditioned by a progressive stimulation protocol. After the muscle was conditioned, multiple-gated equilibrium radionuclide angiocardiography studies showed that left ventricular global ejection fraction was 18.4% ± 7.2% at 0 volts (nonstimulation), 26.2% ± 3.7% at 5-volt stimulation (p horac C ardiovasc S urg 1992;103:1207-13)

The carotid-carotid cervical bypass is one surgical option for symptomatic atherosclerotic lesions of the innominate artery. Controversy exists regarding the necessity of surgically excluding the innominate plaque from the cerebral circuit. A canine study was instituted to characterize the hemodynamic alterations that occur in the right common carotid artery proximal to the bypass graft, termed the critical segment. The direction of flow in the critical segment determines whether emboli originating in the innominate may be propelled cranially despite a patent bypass graft. Six mongrel dogs underwent placement of an autogenous arterial crossover graft as a carotid-carotid bypass. A stenosis of the innominate artery was quantitatively altered, and an electromagnetic flowmeter measured the magnitude and direction of flow in the critical segment at three levels of diameter reduction in the innominate artery. For low-grade stenoses, flow in the critical segment was always prograde. For high-grade stenoses, the flow was always reversed. Stenoses between 57% and 67% yielded flow values of 10 +/- 24 ml/min, and it was in this range that mean flow reversal was found to occur. Even when the mean flow was near zero in the critical segment, flow was not stagnant but oscillated in antegrade and retrograde directions throughout the cardiac cycle. These data indicate that a carotid-carotid bypass causes complete flow reversal in the critical segment when there is high-grade stenosis in the innominate artery. Theoretical analysis of the hemodynamic circuit indicated that arm exercise would augment retrograde flow in the critical segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Full-thickness right ventricular latissimus dorsi dynamic cardiomyoplasty with the Medtronic Cardiomyostimulator (Medtronic, Inc., Minneapolis, Minn.) was performed in a chronic canine model. In one group (n = 2) the latissimus dorsi was electrically preconditioned before cardiomyoplasty. In a second group (n = 3) cardiomyoplasty was performed and the muscle was progressively stimulated, with conditioning accomplished while the latissimus dorsi was functioning on the ventricle. The contribution of the stimulated latissimus dorsi to global ventricular function was assessed, and the effects of varying muscle stimulation parameters on latissimus dorsi function and hemodynamics were examined. Right ventricular systolic pressure increased 8%, from 23.2 ± 0.95 to 25.1 ± 1.5 mm Hg. The rate of pressure rise increased 37% from 226 ± 13 to 309 ± 12 mm Hg/sec. Right ventricular ejection fraction was measured in two dogs and increased 29% with latissimus dorsi stimulation, from 51.5% ± 13.5% to 66.5% ± 14.5%. Although the sample size was small, there was no difference observed between the preconditioned and nonpreconditioned groups. Right ventricular systolic pressure, rate of pressure rise, and percent latissimus dorsi fiber shortening increased as voltage and burst frequency of the muscle stimulus increased, whereas increasing the burst duration had little effect in two dogs so studied. Latissimus dorsi dynamic cardiomyoplasty can function as a partial myocardial replacement in a chronic canine model, apparently without preconditioning of the muscle. The degree of cardiac assist obtained with cardiomyoplasty appears to be influenced by the voltage and frequency of the stimulus applied to the muscle. Although it is unclear whether these results can be extrapolated to the left ventricle, this technique may find application in the treatment of ventricular aneurysm or ventricular tumor.

Increasingly patients are returning for third and even fourth coronary artery bypass grafting (CABG) procedures. The in hospital and long term outcome of patients undergoing a third CABG were reviewed. The time from the first to second CABG was 5.2 ± 3.6 years and from the second to the third CABG 6.7 ± 4.2 years. There were 107 patients, age 60 ± 9 years, 91% were male. 33% had hypertension, 17% diabetes, 86% class III or IV angina and 6.4% congestive failure. 72% had 3 vessel disease. The in-hospital mortality was 9.3%, with 1.9% strokes, and 8.4% myocardial infarction. The 5 and 10 year survival were 0.79 and 0.57. The 5 and 10 year myocardial infarction free survival were 0.59 and 0.26. Patients undergoing a third CABG suffer from severe disease. Most were severely symptomatic, the majority had suffered a myocardial infarction and had 3 vessel disease. Download : Download high-res image (52KB) Download : Download full-size image While operative mortality in patients undergoing a third coronary bypass procedure was reasonable at 9.3%. continuing events over time limit long term prognosis.

Doctor Dwight E. Harken made numerous contributions to the field of cardiac surgery, and in particular the management of cardiac missiles. A few highlights are reviewed.

Tracheobronchial rupture from blunt trauma is usually single and transverse but may be longitudinal or complex, a combination of various sites and forms of rupture. From 1970 to 1990, 183 cases of rupture of the airways were reported in the literature: 136 (74%) transverse, 33 (18%) longitudinal, and 14 (8%) complex. During the same 20 years at Grady Memorial Hospital, 6 patients with such injuries were treated. One had complex injury consisting of rupture of the distal trachea and both main bronchi, 1 had a longitudinal tracheal rupture and rupture of the innominate artery, and 4 had a transverse rupture, 1 of whom also had a traumatic false aneurysm of the left pulmonary artery. Cardiopulmonary bypass was used only for the repair of the complex injury, whereas the repair of the left main bronchial rupture associated with a false aneurysm of the left pulmonary artery was done with standby cardiopulmonary bypass. All 6 patients had satisfactory results from the correction of their lesions except 1 child in whom stenosis developed at the rupture site. This study suggests that complex injuries are rarely seen, and their repair is often quite involved. In some of these cases, the use of cardiopulmonary bypass increases the margin of safety during operation and may encourage repair rather than resection of the affected lung.