A comparison of morphologic and angiographic findings in long-term internal mammary artery and saphenous vein bypass grafts.

Internal mammary artery grafts are currently considered the conduits of choice for myocardial revascularization. Comparisons of long-term morphologic changes in internal mammary artery grafts and saphenous vein grafts and correlation with premortem angiography have not been reported. Eighteen internal mammary artery and 15 saphenous vein grafts that had been in place for 12 to 118 months (mean 56) in 18 patients were removed either surgically or at necropsy and examined histologically. Premortem angiograms were performed within 1 month of histologic study in 15 of these patients. Fibrointimal proliferation was more frequent in internal mammary artery than in saphenous vein grafts 8 [( 44%] of 18 versus 4 [27%] of 15; p = NS). In contrast, atherosclerosis was common in saphenous vein grafts but was extremely rare in internal mammary artery grafts (10 of 15 versus 1 of 18; p = 0.01). A good correlation was noted between the degree of narrowing estimated by angiographic and histologic measurements in both internal mammary artery grafts (d = 0.90) and saphenous vein grafts (d = 0.71). Accelerated atherosclerosis did not occur in internal mammary artery grafts, but was common in saphenous vein grafts. Fibrointimal proliferation was commonly associated with graft narrowing in internal mammary artery grafts and may be an important factor in late graft closure. This study also confirms that internal mammary artery grafts have greater longevity compared with saphenous vein grafts.

Techniques and results of ventricular aneurysmectomy with emphasis on anteroseptal repair.

We have reviewed an 8 year experience with ventricular aneurysmectomy in 170 patients. Ninety percent had anterior aneurysms and underwent "anteroseptal repair" with exclusion of nonfunctioning septal myocardium. Preoperative left ventriculograms and coronary arteriograms were studied and "scored," and the hospital mortality and long-term survival rates for various subsets of the group were correlated with their radiographic data. A postoperative score for the coronary arteries was developed according to the preoperative anatomy and the vessels bypassed. Both the ventriculogram score and the postoperative coronary score had significant effects on both hospital mortality and long-term survival rates. The severity of preoperative coronary disease had minimal predictive value. Recent myocardial infarction did not preclude a good result. The value of an aggressive surgical approach to patients with ventricular aneurysm was confirmed even for certain subsets with indicators suggestive of poor prognosis. Anteroseptal repair appears to give optimal results for the typical "anterior" aneurysm. All suitable coronary arteries should be bypassed. Attention to the details of preoperative anatomy and function allows the most accurate prediction of prognosis and dictates the optimal therapeutic approach.

Cryoprecipitate-topical thrombin glue. Initial experience in patients undergoing cardiac operations.

The use of fibrin glues as topical hemostatic agents is reported in the European literature. We have composed an analogous compound in our operating rooms using cryoprecipitate and topical thrombin (1000 units/ml) in equal volumes applied directly to the bleeding site. We have used cryoprecipitate-topical thrombin glue in 26 patients undergoing cardiac operations. Severe bleeding not responding to usual methods of control was encountered during or after coronary artery bypass (n = 17), valve replacement (n = 3), bypass plus valve replacement (n = 5), or repair of postinfarction ventricular septal defect (n = 1). Five patients were operated on emergently and four were undergoing their second cardiac operation. The glue was used in four patients while on bypass and fully heparinized and in 17 patients who continued to bleed after separation from bypass and administration of protamine. Hemostasis was achieved in all patients and none required reexploration for bleeding. In five patients undergoing reexploration for postoperative hemorrhage (none having received cryoprecipitate-topical thrombin glue during the initial operation), the glue provided hemostasis when other measures failed, and no additional reexplorations were needed. No patient exhibited hypersensitivity, fibrinolysis, or coagulopathy following the use of this glue. In 16 patients followed for 9 to 12 months postoperatively, no hepatitis has occurred. The highly concentrated fibrinogen in cryoprecipitate is activated by thrombin to form fibrin and bring about rapid hemostasis. Cryoprecipitate-topical thrombin glue is a readily available, reliable, and inexpensive topical hemostatic agent in the patient undergoing a cardiac operation.

The fate of arm veins used for aorta-coronary bypass grafts.

Arm veins have been a common second choice conduit for those patients having insufficient saphenous veins for coronary bypass operations. To define the patency and durability of arm vein grafts, we reviewed our patients with one or more arm vein grafts used for coronary revascularization between 1974 and 1982. A total of 59 patients required at least one arm vein graft and 51 are presently alive. Postoperative arteriograms were obtained in 28 patients. Of 56 arm vein grafts used, 32 (57%) were patent and 24 (43%) had failed at 2 years. Seven of the patent grafts had a localized area of stenosis. Sixteen internal mammary artery grafts also had been used in this group of patients, and 15 (93%) were patent. We conclude that arm vein grafts have a high failure rate and are not as dependable as saphenous vein grafts or internal mammary artery grafts.

Ischemic cardiomyopathy: medical versus surgical treatment.

The natural history of patients with ischemic heart disease and depressed left ventricular function is dismal, and medical therapy has failed to alter its course. To assess the results of aorta-coronary bypass grafting in patients with coronary artery disease and decreased left ventricular ejection fraction (LVEF less than or equal to 0.3), we compared 70 medically treated patients to 46 patients having aorta-coronary bypass grafting. The duration of follow-up was 6 to 72 months (mean 19 months). All patients had angina pectoris. Congestive heart failure was present in 56 percent (39/70) of the medical and 43 percent (20/46) of the surgical group. The medical group had a mean LVEF of 0.20 and a mean left ventricular end-diastolic pressure (LVEDP) of 29 mm. Hg. The surgical group had a mean LVEF of 0.21 and a mean LVEDP of 24 mm. Hg. Three vessel disease was found in 60 percent (42/70) of the medical group and 83 percent (38/46) of the surgical group. The operative mortality rate in the surgical group was 4 percent (2/46). There were four late deaths. The 2 year actuarial survival rate for medical and surgical groups was 47 percent and 83 percent, respectively. Significant improvement in angina pectoris and/or congestive heart failure was found in 16 percent (11/70) of medically treated patients and 95 percent (38/40) of the surgically treated patients. Aorta-coronary bypass grafting can be performed in patients with poor left ventricular function with a low operative mortality rate, relief of angina pectoris, and improvement in symptoms of congestive heart failure.

Results of reoperation for failed aortocoronary bypass grafts.

Thirty-one patients underwent reoperation for failure of one or more previous aortocoronary bypass grafts. Thirty-nine grafts were replaced. Twenty-four grafts were constructed to vessels not thought to be significantly diseased at initial operation. There were no early or late deaths. Postoperative morbidity was comparable to initial prodecures. Of 24 patients followed up for more than six months., 62% clearly experienced improvement without evidence of perioperative or postoperative infarction. Reoperation for failed aortocoronary bypass grafts can be achieved without excess risk, but with long-term results less optimistic than initial procedures.

Balloon catheter occlusion of the ascending aorta.

Dense calcification of the ascending aorta predisposes to aortic injury and distal embolization when the aorta is cross-clamped or partially clamped in the performance of cardiac operations. We occluded the ascending aorta with a Foley balloon catheter in 2 patients undergoing aortocoronary bypass grafting. The technique used is described in this report.

Air embolism and other accidents using pump oxygenators.

A surgery of 349 cardiac surgeons showed that during a six-year period, a pump oxygenator accident serious enough to cause patient injury or death occurred one per 1,000 procedures. A total of 264 deaths occurred as a direct results of an accident. Air embolism and disseminated intravascular coagulation were the two most common problems. Low-level alarm systems were reported to be used by 42% of the respondents and activated clotting times were used by 63%. Rigorous use of alarm systems and heparin monitoring could reduce the incidence of pump-related accidents.

Median sternotomy dehiscence.

Sternal dehiscence requiring reoperation occurred in 36 out of 4,531 patients who had a sternotomy incison within an eight-year period. Twisted sternal wire sutures were used for the first four years and a crimped steel plate fixation was used during the second four years with a marked and significant decrease in the incidence of dehiscence from 17 out of 1,000 patients to 3 out of 1,000 patients. Thirty-five of the 36 patients were men, and 4 required reoperation for bleeding. Other factors such as mammary artery dissection, tracheostomy, and body weight of more than 82 kg were not significant. Although infection was noted in 20 patients, it was thought to be secondary. Early reoperation with antibiotic irrigation achieved wound stability in the 34 survivors with only 3 patients requiring additional procedures for chronic osteomyelitis of the sternum.

The effectiveness of surgical treatment of acute aortic dissection.

Ten consecutive patients have undergone operative repair of acute aortic dissection at St. Thomas Hospital in the last three years. Two died. To assess the status of the residual aorta, all 8 survivors were evaluated by postoperative aortography. Only the patient with a clotted dissection on preoperative study showed no residual dissection of the distal aorta. Analysis of postoperative aortograms suggests that the original dissection reentry points become sites of inflow following removal of the original intimal tear. No death resulted from these residual abnormalities. Retrograde dissection and aortic insufficiency were obliterated. The major sites of aortic rupture were removed. It is concluded that surgical therapy for acute aortic dissection is effective in that it avoids the major sources of mortality. The resultant surviving population must be carefully observed in view of the high frequency of residual aortic abnormality.

Pulmonary embolectomy.

During the past 10 years, 20 patients at St. Thomas Hospital had pulmonary embolectomy; there were 12 survivors. Ten patients had a pulmonary arteriogram prior to operation and, of these, there were 7 survivors. The remaining 10 patients were seen with circulatory collapse and were taken immediately to the operating room without definitive diagnostic studies. Ten patients were undergoing cardiopulmonary resuscitation at the time of the embolectomy and, of these, there were 5 long-term survivors. This review indicates that immediate diagnostic studies, such as lung scan or pulmonary arteriogram, should be undertaken as soon as the diagnosis of pulmonary embolus is entertained. Patients with sudden collapse, in the appropriate clinical setting, should be transported to the operating room as soon as possible. It would also appear that patients who are unresponsive to the usual measures of cardiopulmonary resuscitation are still reasonable candidates for pulmonary embolectomy, and this may represent their only change for survival. Patients in whom massive pulmonary embolus is confirmed by angiography should be considered for early pulmonary embolectomy despite a relatively stable hemodynamic and clinical picture.

Prophylaxis of atrial fibrillation with magnesium sulfate after coronary artery bypass grafting.

Ninety-nine consecutive consenting patients were prospectively entered into a randomized, double-blind, placebo-controlled trial to determine the efficacy of postoperative magnesium therapy on the incidence of cardiac arrhythmias after elective coronary artery bypass grafting. No patient had documented or suspected arrhythmias preoperatively. Forty-nine patients received 178 mEq of magnesium given over the first 4 postoperative days, and 50 patients received only placebo. The clinical characteristics of both groups were similar. The preoperative mean serum magnesium concentration was similar in both study (1.90 mEq/L) and placebo (1.90 mEq/L) groups. The mean postoperative serum magnesium concentration in study patients was significantly elevated over postoperative days 1 through 4 when compared with preoperative levels (p less than 0.001). The postoperative mean serum magnesium concentration in control patients declined and remained significantly depressed through postoperative day 3 (p less than 0.001), but increased to preoperative levels by postoperative day 4. The mean serum magnesium concentration was significantly greater in the study patients as compared with the control patients over postoperative days 1 through 4 (p less than 0.001). Although there was no significant difference between groups with respect to episodes of ventricular arrhythmias, there was a significant decrease in the number of episodes of atrial fibrillation in the group receiving magnesium therapy (p less than 0.02). There were no recognized adverse effects of magnesium therapy. Prophylactic magnesium administration seems to lessen the incidence and severity of atrial fibrillation after coronary artery bypass grafting.

Revascularization of the septal artery.

The septal artery has been infrequently considered for bypass grafting due to its apparent inaccessibility. Twelve patients have recently been found to have a large single obstructed septal artery that supplied an area of left ventricle great enough to justify revascularization. A review of 100 normal arteriograms showed that 30% (30/100) of the patients had a septal artery of sufficient size to sustain a graft. Early restudy of 8 of the 12 patients who received septal bypasses showed all grafts to be patent and functioning well.

Recognition and operative management of patients with arteriosclerotic coronary artery aneurysms.

Arteriosclerotic aneurysms of the coronary arteries have been noted in 38 patients undergoing cardiac surgical procedures. Age, sex, and risk factors are similar to those in other patients with coronary artery disease. A high incidence of previous myocardial infarction (24 of 38) is related to the frequency of clot formation and embolism associated with such aneurysms. There is also an increased risk of perioperative infarction following coronary artery bypass grafting if the suture line involves the aneurysm wall (6 of 6), but not when sutures are placed away from it. The importance of recognition and proper operative management is stressed.

Aberrant right subclavian artery aneurysm.

Ten patients with aneurysm of an aberrant right subclavian artery have been previously reported. Dysphagia is not commonly part of the initial symptomatology, and the diagnosis is usually established by chest roentgenogram, esophagogram, and aortography. If operative intervention is planned, adequate preparation for bypass and thoracic aortic grafting should be made since the aneurysm may also involve the descending thoracic aorta at the site of origin of the aberrant subclavian artery. Since both ischemia of the involved arm and the subclavian steal syndrome may occur after division of the origin of the subclavian artery, resotration of arterial flow in the distal subclavian artery is preferred. An additional patient is reported in whom right subclavian-to-carotid artery anastomosis was used after the subclavian artery aneurysm was removed.

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.

The natural history of long-term cardiac pacing.

During the past ten years, 504 patients have received one or more pacemakers for complete heart block or other arrhythmia. Of these patients, 306 (61%) are alive. Actuarial analysis shows a steady attrition of 9.4% per year for the first five years, decreasing to 7% per year for the second five years. The overall survival was decreased for patients with congestive heart failure and advanced age and was not affected by the history of Stokes-Adams attacks, initial pulse rate below 50 per minute, or a QRS duration greater than 0.12 second prior to pacing. Cardiac problems were the primary cause of death in 71% of the patients. The natural history of patients with permanent pacemakers depends, more than any other factor, on the function of the left ventricle.

The incidence of venous thrombosis following long-term transvenous pacing.

Long-term cardiac pacing with permanent transvenous electrodes has achieved wide acceptance with only occasional reports of venous obstruction and edema. To determine the incidence of venous abnormalities associated with transvenous electrodes, 34 venograms were obtained in 32 patients paced 18 months or longer. Eleven venograms demonstrated severe obstruction with collateral circulation communicating with the opposite cervical and innominate venous channels; 7 of these showed total occlusion. Seven venograms revealed no obstruction. The remaining 16 venograms showed venous stenosis without collaterals. It is concluded that venous abnormalities associated with permanent transvenous pacing occur commonly but are not usually associated with arm or facial edema.

Internal mammary artery grafts: technical factors influencing patency.

Eight hundred fourteen patients with internal mammary artery (IMA) coronary artery bypass grafts have been restudied 961 times with coronary arteriography, primarily to evaluate the patency of the grafts in the setting of symptomatic coronary occlusive disease. Their records were reviewed to assess graft patency as related to the technical aspects of coronary artery bypass surgery. Patency was evaluated using life-table analysis of the data. The method of harvesting the IMA played no role in patency. The left anterior descending coronary artery was the recipient coronary artery with the highest patency rate. The left IMA had a significantly higher patency rate than the right IMA. As a group, the IMAs had a significantly higher patency rate than saphenous vein grafts. However, there was no difference between right IMA grafts and saphenous vein grafts. The mammary artery grafts that remained patent throughout the study had a significantly higher blood flow after bypass than did those that became occluded (43.0 +/- 0.9 versus 28.9 +/- 1.8 ml/min; p less than .001).

Unexpected death following aortocoronary bypass.

Since 1968, 1,800 aortocoronary bypass procedures have been performed with 37 operative or early postoperative deaths (2.1%). Twenty-one deaths (57%) occurred in patients with one or more of the following predetermined risk factors: ventricular aneurysm, decreased left ventricular contractility, left main coronary artery stenosis, valve replacement, recent infarction, or cardiogenic shock. The remaining 16 deaths (43%) were unexpected and occurred in patients with none of these risk factors.