Early Postoperative Development of Aortic Regurgitation Related to Pannus Ingrowth Causing Incomplete Disc Seating of a Björk-Shiley Prosthesis

Incomplete seating of the disc of a recently implanted Björk-Shiley aortic prosthesis occurred because of excessive ingrowth of fibrous tissue. This resulted in significant aortic regurgitation plus hemolytic anemia. Reoperation with identification of the problem and implantation of a Hancock bioprosthesis was required for resolution of the situation.     

Comparative Hemodynamic Properties of Vein and Mammary Artery in Coronary Bypass Operations

To understand better the observed differences in bypass flows between vein and internal mammary artery (IMA) grafts, a technique was devised for anastomosing both vein and IMA to the same anterior descending coronary artery in 14 patients. In the stable postperfusion state, flows in the two bypass conduits were simultaneously recorded as well as pressure relationships in both grafts and the left ventricle. The supply/demand ratio for left ventricular performance was calculated with respect to the diastolic pressure-time index/tension-time index (DPTI/TTI) for each bypass independently and simultaneously and then compared. The DPTI/TTI ratio was nearly two times greater with the vein bypass than with the IMA. This difference was further confirmed by the flow studies, in which blood flow through the vein ranged 2 to 3 times higher than IMA flow to the same coronary bed.By present criteria the DPTI/TTI ratio for IMA grafts to the left ventricle was inadequate in the majority of patients studied, and atrial pacing markedly lowered the DPTI/TTI ratio of the IMA. The choice of vein or IMA as abypass is a critical determinant of the resultant bypass — left ventricular DPTI/TTI ratio. Vein bypasses exhibited far superior hemodynamic capability in the resting state, and the effect of atrial pacing on the DPTI/TTI ratio in IMA–vein–left ventricle bypasses confirms this point.     

Functional Benefits Following Coronary Artery Bypass Graft Surgery

While some studies of patients who undergo cardiac surgery have included such outcome measures as amounts of symptom reduction and rates of resumption of employment, little attention has been focused on the extent to which these patients have experienced the simple, yet very important, broad range of functional benefits that might be anticipated by clinicians to result from operation. The present report seeks to document the extent of improvement that does exist in terms of physical, sexual, and social-role functioning. In a cohort of 340 patients (age, 32 to 69 years) studied before and six months after coronary artery bypass operation, improvements were noted in each of three dimensions of functional benefit: physical functioning (fewer total activity restrictions or incapacitated days per month), sexual functioning (through increased energy and desire and decreased pain and worry), and role functions (ability to work, social participation, and pursuit of hobbies). Further improvements might be anticipated with additional months of recovery.     

The Structural Study of the Saphenous Vein

From November, 1971, to September, 1974, 1,179 patients received aortocoronary saphenous vein bypass grafts at the Cleveland Clinic Hospital. Segments of saphenous vein from each patient were sent for microscopical analysis. These vein segments were classified as normal or abnormal (phlebosclerotic). Four hundred ninety-six normal vein grafts in 295 patients were restudied and had a patency of 87.9%. One hundred forty-four abnormal vein grafts in 86 patients were restudied and showed 89.5% patency.This study suggests that histopathological identification of an abnormal (phlebosclerotic) vein segment does not constitute a determining factor as far as late patency is concerned in a vein segment that is not grossly sclerotic.     

Coronary Artery Bypass Grafting: Simplification and Refinement of Surgical Technique

Recent advances in technique and myocardial preservation that I have used in performing the coronary bypass operation are described. Rigid adherence to basic microsuture technique and use of hypothermic hyperosmolar cardioplegic solution and wide-field optical magnification have been responsible for improving graft patency rates and markedly reducing operative mortality during the past six years. With these techniques, hospital mortality has been 0.6% (3 deaths) in the last 500 consecutive coronary bypass operations.     

Placement of Coronary Artery Bypass Graft Without Pump Oxygenator

Patients undergoing open-heart operations are subject to morbidity related to the use of extracorporeal circulation. Peripheral experience gained from its use can be brought together to enable some of the operations to be performed without subjecting the patient to cardiopulmonary bypass.Right coronary and left anterior descending coronary artery grafting with vein or internal mammary artery can be done on the beating, functioning heart by stabilizing the distal anastomotic site with transfixion sutures and by perfusing the obstructed coronary artery from its own aorta through a cannula which also acts as a stent at the site of anastomosis. High oxygenation levels offer protection to the manipulated heart, and the use of heparin appears to ensure patency of the graft at operation.A series of 63 patients is reported in which there was no mortality related to the cardiac operation and only 1 death related to a presumed cerebrovascular accident. Cardiopulmonary bypass support was not required in any patient selected for this technique.     

“No-Vent” Technique of Coronary Artery Bypass

Isolated coronary artery bypass grafting was performed in 100 patients without the use of a left ventricular vent. Distention of the left ventricle did not occur. There was 1 late death unrelated to this technique. Vents in the left heart are not required under most circumstances.     

Intimal Hyperplasia: A Cause of Radial Artery Aortocoronary Bypass Graft Failure

Autogenous radial artery grafts have been advocated for those situations in which adequate saphenous vein is not available for aortocoronary bypass procedures. It was anticipated that autogenous artery would demonstrate less predilection to develop the intimal proliferative changes seen with vein grafts in the arterial system. Early clinical experience with 79 patients receiving one or more radial artery grafts has shown that the radial artery is not spared occlusive intimal proliferative changes. Although early restudy of 6 patients was encouraging, late restudy in 29 patients showed 22 of 34 radial artery grafts (64.7%) to be unsatisfactory. Recovered grafts from 3 patients who required a second operation revealed severe generalized intimal hyperplasia. On the basis of this experience we no longer consider the radial artery an alternative conduit for aortocoronary bypass.     

Technique for the Coronary Snake Graft Operation

The use of one end-to-side anastomosis with side-to-side technique for all additional vein-coronary anastomoses has given continually good results and has been used in 227 of 411 patients undergoing vein graft operations, including all multiple graftings done since April, 1972. The operative mortality was 4.6%.Arteriography by the end of the third postoperative month has been obtained in 98.4% of the 377 eligible patients. It showed that 98% of the 304 side-to-side anastomoses were patent, with 289 (95%) having unrestricted communication with the aorta. The proximal segment was widely patent in 193 (97%) of the 200 patients with snake grafts having postoperative arteriography. The distal end-to-side anastomosis was patent in 176 (88%) of these 200 patients. The average was 2.3 unrestricted grafts per patient. These results are better than the patency rates of 89 and 87% obtained previously with single and Y-grafts, respectively.Technical details have been worked out for construction of suture lines, choosing the correct length for segments, obtaining a reliable proximal segment, routing grafts to multiple coronary branches, and removing air from the grafts.     

Emergency Coronary Revascularization in the Early Postoperative Coronary Artery Bypass Patient

A patient underwent myocardial revascularization for acute ischemia following early postoperative graft closure and ventricular fibrillation. Extensive myocardial infarction was prevented by electrocardiographic and enzyme criteria. The time lapse between onset of the ischemic episode and revascularization is critical. Our knowledge of the patient's coronary anatomy obviated the need for angiography; the graft occlusion was diagnosed by electrocardiogram.     

Coronary Artery Bypass Grafts: Increased Flow in the Early Postoperative Period

The long-term outcome of coronary artery bypass operations is contingent upon the patency of aortocoronary bypass grafts. Flow measurements taken at operation may not truly reflect the capacity of the graft to carry flow because the heart may not have fully recovered from the consequences of ischemic arrest, despite the protective effects of hypothermic cardioplegia.During a three-year period, we observed increases of up to 200% in the flow rate of 8 of 11 saphenous vein grafts in 7 patients who underwent reoperation for bleeding or cardiac tamponade in the early postoperative period. At initial operation, flow rates ranged from 25 ml/min to 130 ml/min (mean value, 66.8 ± 10.3 ml/min [standard error of the mean]). At reexploration, flow measurements ranged from 0 ml/min (graft clotted) to 260 ml/min (mean value, 110 ± 22.8 ml/min). This difference was statistically significant (p < 0.02). This study documents that flow rate measurements in saphenous vein aorotocoronary bypass grafts can increase in the early postoperative period although the exact mechanism by which this occurs is not known.     

Comparison of Dopamine and Dobutamine Following Coronary Artery Bypass Grafting

A prospective, randomized comparison of the hemodynamic effects of dopamine and dobutamine was performed in 20 patients following coronary artery bypass grafting. Approximately 6 hours postoperatively, when patients were hemodynamically stable, either dopamine or dobutamine was administered at 2.5, 5.0, and 7.5 μg per kilogram of body weight per minute. At 5.0 μg/kg, both drugs increased cardiac index without changing heart rate, mean arterial pressure, pulmonary capillary wedge pressure, or peripheral vascular resistance. At 7.5 μg/kg, dobutamine caused a further increase in cardiac index without changing the other variables. In contrast, increasing dopamine from 5.0 to 7.5 μg/kg/min caused significant increases in mean arterial pressure, pulmonary capillary wedge pressure, and pulmonary vascular resistance but no further increase in cardiac index. We conclude that dobutamine is preferable to dopamine in patients following coronary artery bypass grafting, since it produces consistent, dose-related increases in cardiac index without increases in heart rate, mean arterial pressure, pulmonary capillary wedge pressure, or pulmonary vascular resistance.     

Coronary Artery Bypass Operation in Septuagenarians

Increasing numbers of patients more than 70 years old are at risk from coronary artery disease. The continued success of coronary artery bypass operation in selected patients provides impetus for applying this procedure to older patients as well. Our results indicate coronary artery operation is effective in older patients and has a low mortality (3% in our series). In patients in this age group, coronary artery operation can be combined with other procedures, when indicated, such as cardiac valve replacement or repair, left ventricular aneurysmectomy, carotid endarterectomy, and cholecystectomy.     

Myocardial Revascularization of the Canine Circumflex Coronary Artery Using Retrograde Internal Mammary Artery Flow Without Cardiopulmonary Bypass

A new surgical technique using perfusion of the circumflex coronary artery with retrograde blood flow of the internal mammary artery (IMA) is described. This project was undertaken because the IMA is uniquely well supplied with blood: proximally through its attachment to the subclavian artery, along the sternum by the intercostal arteries to the aorta, and distally from the iliac artery by the epigastric and musculophrenic arteries.In this experimental study, the IMA in 16 dogs was ligated and divided at the subclavian artery, then dissected free down along the sternum to obtain sufficient length. The large subclavian end was then anastomosed to the circumflex coronary artery using a metal cannula technique to perfuse the circumflex bed while the anastomosis was being done. In all 16 dogs, the retrograde flow of the IMA was adequate to maintain the circumflex bed. It is postulated that this technique may have some limited use in man.     

Congenital Coronary Aneurysms Nine Years Following Saphenous Vein Bypass Graft Surgery

A 34-year-old woman with two congenital coronary aneurysms received a saphenous vein bypass graft (SVBG) as treatment for a thrombosed right coronary artery aneurysm 9 years ago. The angiographic and surgical findings were reported at that time [1]. In 1979, she received a sequential SVBG to the left anterior descending and first diagonal coronary arteries following recurrence of angina and progressive occlusion of the left coronary artery aneurysm. She is believed to have the longest angiographically documented course following operation, and her case history is reported to aid in establishing the natural history of this unusual condition and its surgical management.     

Can the Frequency of Myocardial Infarction Be Reduced during Coronary Artery Operations?

A prospective experiment was carried out in 56 patients undergoing coronary artery revascularization to determine whether those having a glucose-insulin-potassium (GIK) perfusion during the procedure would have fewer myocardial infarctions (MI) compared with patients given a control perfusion of Normosol-R. Six patients (11%) developed an MI, defined as a 24-hour creatine phos-phokinase MB isoenzyme value of 100 IU per liter or greater. Four (13%) had control perfusions and 2 (8%) had GIK perfusion. One MI in a double-graft recipient who had GIK perfusion occurred because of a technical surgical error; therefore, the corrected MI rate was 13% in control patients compared with 4% for the GIK group. These data, as well as the more frequent spontaneous defibrillation in patients who had GIK perfusion, suggest that GIK was of benefit.     

Surgical survival in the Coronary Artery Surgery Study (CASS) registry

The overall surgical survival data in the Coronary Artery Surgery Study (CASS) registry have not been published to date, pending the report of the randomized medical-surgical comparison (CASS randomized trial). Non-randomized surgical survival data from the CASS registry are given in this article. The overall medical survival data from the registry were reported previously as a natural history study. There were 8,991 patients in the registry portion of CASS who had primary isolated coronary artery bypass grafting and 8,971 with follow-up of more than 30 days. The 5-year survival for all 8,971 patients was 90%, and the operative mortality was 2.37%. Patients with left main coronary artery disease had an operative mortality of 3.84% and a 5-year survival of 85%, while patients with lesions in other vessels had an operative mortality of 2.12% and a 5-year survival of 91%. Among patients without left main coronary disease, the 5-year survival was 93% in those with single-vessel and 92% in those with double-vessel disease (operative mortality was 1.50% and 1.92%, respectively) and 88% in patients with triple-vessel disease (operative mortality was 2.62%; p = 0.009). When results for patients with left main coronary artery obstruction were compared with those for triple-vessel disease, the 5-year survival figures were 85% and 88%, respectively (p = 0.02) and the operative mortality, 3.84% and 2.62%, respectively (p = 0.03). Patients with normal or nearly normal left ventricular (LV) function (i.e., LV segmental wall motion scores ranging from 5 through 11) had a 5-year survival of 92% and an operative mortality of 1.97%. Patients with moderate impairment (LV score range, 12 through 16) had a 5-year survival of 80% and an operative mortality of 4.21%. In those with poor ventricular function (LV score of 17 or greater), the 5-year survival was 65% and the operative mortality was 6.21%. The difference in survival among the three groups was significant (p less than 0.0001). Of 29 variables used in a stepwise Cox regression analysis, LV wall motion score, congestive heart failure score, age, number of operable vessels, smoking history, LV end-diastolic pressure, and percent of left main coronary artery stenosis were found to have a significant effect on long-term survival (excluding 30-day mortality), and these variables plus surgical priority and height influenced surgical mortality. When height was used in the Cox proportional hazards model, female sex was no longer a significant variable.     

Detection of Myocardial Injury after Coronary Artery Bypass Grafting Using a Hypothermic,Cardioplegic Technique

Fifty patients undergoing isolated coronary artery bypass grafting procedures using a clear, cold cardioplegic solution, topical hypothermia, and reduced systemic flow for intraoperative myocardial protection were evaluated for myocardial injury by serial plasma creatine kinase–MB isoenzyme (CK-MB) measurements and electrocardiograms. Forty-one (82%) of the patients had three-vessel disease. Preoperative left ventricular contractility determined angiographically was normal in 13 patients (26%), mildly abnormal in 26 (52%), and moderately or severely abnormal in 11 (22%). The number of arteries grafted ranged from 2 to 6 (mean, 3.5). The mean duration of aortic clamping was 38.6 ± 1.6 minutes. There were no hospital deaths. Enzymatic and electrocardiographic (ECG) evidence of myocardial infarction occurred in 1 patient. Nonspecific ECG changes occurred in 16 patients (32%), and the electrocardiograms were unchanged in the remaining 33 patients (66%). In the 49 patients without ECG evidence of infarction, the mean peak plasma CK-MB value, which occurred 6 hours after the onset of cardiopulmonary bypass, was 7.9 ± 0.8 IU/L (standard error of the mean) and the mean integrated area 158 ± 19.5 IU/L × hours. There was no correlation between these CK-MB values and the extent of disease, number of arteries grafted, or the duration of myocardial ischemia. These data document a low incidence of perioperative myocardial injury with this technique, and can serve as a baseline for comparison with other techniques for intraoperative myocardial protection in this setting.     

Saphenous Vein Aortocoronary Bypass Graft in a Dog: Thirteen-Year Follow-up

A reversed autogenous saphenous vein graft placed between the ascending aorta and the nonstenosed circumflex coronary artery in a dog was studied thirteen years after operation. The aortic anastomosis was round despite the fact that only a slit aortotomy was originally made. The heel side of the distal anastomosis was narrowed but the toe side was not. The intimal thickening was very minimal, and the elastic membrane was intact.