Alfred J. Tector

Atherosclerosis of the internal mammary artery.

To better evaluate the incidence of atherosclerosis in the internal mammary artery (IMA), 215 IMA segments from routine postmortem examinations were evaluated microscopically. Significant atherosclerotic narrowing was seen in 9 patients (4.2%). No patient had more than a 50% reduction in lumen diameter. The degree of incipient atherosclerosis correlated well with age, hypertension, diabetes, and peripheral vascular disease.

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 a bypass 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.

Left main coronary artery stenosis; results of coronary bypass surgery.

Fifty-six patients with severe stenosis of the left main coronary artery underwent coronary bypass surgery between January 1970 and December 1971. All patients had angina pectoris. Seventy-five per cent of the patients had an unstable anginal pattern. There were six perioperative deaths for a surgical mortality of 10.7%. Of the 50 patients surviving surgery, 96% are alive from 12 to 36 months postoperatively, 90% have had a significant reduction in anginal symptoms and 76% are asymptomatic. Postoperative catheterization studies, performed one to 28 months after surgery in 31 patients, showed that 83% of 75 bypass grafts were widely patent. In each patient studied there was at least one widely patent graft to the left coronary artery. Six patients had exercise studies using supine bicycle ergometry during pre- and postoperative cardiac catheterization. These studies demonstrated improvement in exercise tolerance and in left ventricular hemodynamics after coronary surgery.

Late Results of Saphenous Vein Bypass Grafting for Myocardial Revascularization

Abstract Data from three large groups of patients undergoing aorta-to-coronary artery saphenous vein bypass grafting with follow-up angiograms between 0 and 32 months and postoperative clinical evaluation for up to 46 months enable us to say there is an early saphenous vein closure rate of 9%. These closures are probably related to technical judgment difficulties and lend themselves to improvement in results. The documented late closure rate in 92 patients followed a mean of 31.7 months was 13%. This is a rate of one late closure per 171 patient-months. Of the 92 patients, 80 had some effective vein graft functioning in this follow-up period. Histological evaluation has revealed subintimal fibrous hyperplasia to be the predominant factor involved in late closure of the vein bypass. Its manifestations are variable, and the multifactorial etiology is as yet unclear. Since 5% of vein grafts have some significant subintimal fibrous hyperplasia at the time of insertion, only close follow-up with correlation of operative, angiographic, and histological data will provide the answers to the question of etiology of late vein graft closure. Studies on the effect of trauma, vascularity, and nutrition of vein grafts are necessary. The answer to this problem will be necessary to set the coronary vein bypass procedure on a firm footing in the treatment of coronary artery disease.

ATHEROSCLEROSIS INVOLVING THE INTERNAL MAMMARY ARTERY

Abstract Three patients undergoing coronary artery bypass operation at this institution over a two-month period were found to have significant atherosclerotic disease involving the internal mammary artery. All 3 patients were relatively young men with hypertension and severe three-vessel coronary involvement. Continuing experience with the internal mammary artery plus subsequent extensive postmortem dissections have supported our impression that atherosclerosis involving the internal mammary artery is much more prevalent than previously implied. Techniques for evaluating this vessel both preoperatively and intraoperatively are discussed.

Factors Predictive of Perioperative Myocardial Infarction during Coronary Operations

The diagnosis of perioperative myocardial infarction (PMI) in our patients was based upon electrocardiography, vectorcardiography, and postoperative enzyme changes. A group of 303 patients operated on between January and September, 1972, formed the basis of this study. Three groups were identified from among these patients. Group A was composed of 90 consecutive patients in whom MI was excluded by all criteria. Group B comprised 25 patients with proved MI and yielded the 8% incidence of MI among our patients. Group C included 34 patients with triple-vessel disease who did not sustain MI. Significantly more patients sustaining MI had preinfarction angina and severe coronary artery disease. The incidence of MI was also higher in patients with diffuse disease and those in whom the lesions could not be totally bypassed. A statistical correlation with longer pump runs and periods of anoxia was obtained. There was some suggestion that the preoperative location of the hypokinetic segment determined the site of MI in patients.

Experience with the Björk-Shiley Prosthetic Valve

One hundred and eighty-nine patients who had valvular replacement with 213 Björk-Shiley prosthetic heart valves are presented who are 6 months to 2½ years postoperative. Surgical mortality was 2.6% in mitral valve replacement and 8.8% in aortic valve replacement. The late mortality for the entire series was 2.9%. Four patients had episodes of embolization, all from mitral prostheses. Only two incidences of paraprosthetic leaks were noted in patients with mitral valves, and none in patients with valves in the aortic position. The authors believe this prosthesis to be superior in its hemodynamic characteristics and wear durability, with few late complications.

Experience with Internal Mammary Artery Grafts in 298 Patients

The internal mammary artery (IMA) was used as a graft in 298 patients undergoing coronary bypass procedures. Two patients died during the operative period and 2 others died one year later. Most of the survivors are free of angina. Of the IMAs restudied 9 to 24 months postoperatively, 95% were patent. This group included nearly all the patients having angina after operation. There are some situations in which the IMA may have inadequate flow in comparison to the vein graft. These results suggest the IMA is an excellent graft in most coronary bypass procedures.

Surgical Management of Idiopathic Hypertrophic Subaortic Stenosis

Abstract Ten of 11 patients were successfully operated upon for severely symptomatic idiopathic hypertrophic subaortic stenosis (IHSS). The operative techniques utilized were myotomy in 9 patients, myotomy and mitral valve replacement in 1 patient, and mitral valve replacement alone in 1 patient. Intraoperative and late postoperative measurement of gradients have shown abolition of or a marked decrease in gradients in 8 patients studied. With 1 exception, all 10 survivors are now in N.Y.H.A. Functional Class I or II. One patient suffers from persistent left heart failure and remains in Class IV. Significant mitral insufficiency was abolished by operation in all but 1 patient. Myotomy is an effective and safe operative technique in the treatment of IHSS. Mitral valve replacement should be undertaken if myotomy does not relieve obstruction.

Multiple cardiac injuries secondary to a single stab wound.

A case of multiple cardiac injuries secondary to a single stab wound is described. The extent of the injury was not fully appreciated at the initial surgical intervention and typical clinical manifestations were delayed in appearance. Cardiac catheterization was necessary to confirm the correct diagnosis. After the correct diagnosis was made, surgical repair was successfully performed.