Aortocoronary Saphenous Vein Bypass Surgery Research Articles

Atherosclerosis and coronary bypass surgery in hereditary factor VII deficiency

A 66-year-old man with homozygous deficiency of factor VII (less activity than 4 percent of normal) had a minimal hemorrhagic tendency and severe coronary atherosclerosis, and underwent aortocoronary saphenous vein bypass surgery. Although plasma factor VII coagulant activity and cross-reacting material were markedly reduced, comparable amounts of factor VII antigen were detected in peripheral blood mononuclear cells of both the patient and of a normal subject by Western blotting techniques. Accelerated coagulation was observed following brief exposure of the patient's phytohemagglutinin-stimulated peripheral blood mononuclear cells to low concentrations of ambient factor VII in vitro. Evidence indicates that factor VII plays a role in vivo in both hemostasis and atherogenesis and it might be assumed that factor VII deficiency would both predispose to excessive bleeding and forestall atherosclerosis. However, these observations suggest that factor VII-mediated thrombin generation may proceed by partitioning of small amounts of factor VII on tissue factor-expressing cells and that factor VII contained within monocytes may facilitate tissue factor-induced coagulation by these cells. These features may provide efficient coagulation activation despite a deficiency of the plasma coagulant protein. The current results may explain, at least in part, the minimal bleeding tendency, and also the occurrence of thrombosis and atherosclerosis in certain persons with factor VII deficiency.

Atherosclerosis after coronary artery bypass surgery: results of recent studies and recommendations regarding prevention.

Atherosclerosis is the most frequent cause of occlusion of aortocoronary saphenous vein grafts between 5 and 10 years after coronary artery bypass surgery. The typical atherosclerotic plaque appears between 1 and 3 years after operation and, at a mean of 5 years, histologic changes of atherosclerosis are present in 21% of grafts and in 27% of patients. Only approximately 60% of saphenous vein grafts remain patent at repeat angiography between 10 and 12 years after bypass surgery; 45% of patent grafts show atherosclerotic changes at angiography and 43% of patients show evidence of atherosclerosis in one or more saphenous vein grafts. We do not know whether the development or the progression of these atherosclerotic changes can be modified; however, the data currently available suggest that the administration of platelet inhibitors and/or of lipid lowering agents offer two promising avenues of investigation in patients undergoing aortocoronary saphenous vein bypass surgery. Until this has been carefully studied, the internal mammary artery should remain the preferred conduit for aortocoronary bypass grafting, whenever possible.

Does aortocoronary saphenous vein bypass surgery change the native coronary arteries? An angiographic follow-up of 60 patients.

ABSTRACT. Progression of disease in the native coronary circulation was studied in 60 patients before and after aortocoronary saphenous vein bypass surgery. The mean interval between the first angiographic study and operation was 2.0 months and the mean interval from operation to second catheterization was 15.3 months. The results from a second arteriographic study after an interval of 12.3 months on 25 comparable patients, with no surgery in between, served as a control material for frequency and severity of the “natural” progression of the disease. Only vessels which were not occluded at the first examination were included in the re‐study. In the 60 operated patients, 106 arteries were grafted and 74 ungrafted. Total graft patency at the time of re‐study was 66%. Progression was found in segments proximal to the anastomosis in 42% of arteries with patent graft, and in 47% of arteries with occluded graft, whereas in segments distal to the site of anastomosis progression was found in 5% of the arteries with patent graft and in 55% of arteries with occluded graft. Progression of the disease was found in 11% of ungrafted arteries. In the control group, progression of the disease was found in 24%. The study thus shows that after aortocoronary bypass surgery, progression in segments proximal to the anastomosis is significantly higher than in nongrafted arteries. The progression was independent of patency or occlusion of the graf to the vessel. Progression in the segments distal to the anastomosis was not significantly different from the frequency of progression seen in nongrafted arteries if the graft was patent, but was much higher if the graft was occluded.

Thallium-201 myocardial scintigraphy in patients with triple-vessel disease and ischemic exercise stress tests.

Thirty patients with triple-vessel coronary artery disease proven by angiography, symptomatic angina and a positive ECG stress test were evaluated with thallium-201 (201TI) scintigraphy. Twenty patients also had aortocoronary saphenous vein bypass surgery; 15 of them had repeat noninvasive evaluation. Seventy percent of these patients showed ischemia by 201TI scintigraphy, of which one-half returned to normal after surgery. Postoperative reversion of the ECG stress test together with 201TI stress/reperfusion imaging correlated well with the completeness of surgical revascularization. We could not explain the prevalence (80%) of infarcts detected by 201TI in this group, of which 76% could be anatomically correlated to epicardial scars. The positivity of infarcts by 201TI exceeded that predicted by previous history of infarction, Q waves on resting ECG or ventriculographic akinesis. These observations suggest that 201TI scintigraphy is a useful noninvasive tool in the follow-up and understanding of patients with coronary heart disease. These conclusions also support the concept that 201TI stress imaging need not have the identical connotation as the ECG stress test.

Myocardial infarction after aortocoronary saphenous vein bypass. Vectorcardiographic study.

Vectorcardiograms and scalar electrocardiograms were recorded in 30 patients before and after aortocoronary saphenous vein bypass surgery to determine whether vectorcardiograms are helpful in making the diagnosis of perioperative transmural infarction. The vectorcardiogram indicated inferior infarction in 2 cases and anterior infarction in 1 case when the diagnosis was not apparent on the electrocardiogram. In the solitary case of anterior infarction diagnosed by the electrocardiogram, anterior infarction was already present on the preoperative vectorcardiogram. The study indicates that the recording of vectorcardiograms before and after aortocoronary bypass surgery facilitates the diagnosis of perioperative anterior and inferior infarction and may reveal perioperative infarction about a previously infarcted area.

Impending myocardial infarction: medical management.

It is our practice to suggest coronary arteriography for patients with impending myocardial infarction who respond poorly to medical managemnt. Aortocoronary saphenous vein bypass surgery is advised for patients with unstable angina and left main coronary disease. Surgery is not advised for patients with minimal irregularities of the coronary arteries (less than 50% obstruction). Rarely is surgery advised for patients with the syndrome of impending myocardial infarction in whom only the right coronary artery or the left circumflex artery is obstructed. Bypass surgery should be seriously considered for patients with unstable angina and hemodynamically significant disease involving the proximal left anterior descending coronary artery (proximal to the first septal perforating branch). On the basis of symptomatic improvement alone, surgically treated patients with the syndrome of impending myocardial infarction seem to fare better than do those treated medically.

Enhanced rate of progression of coronary artery disease following aortocoronary saphenous vein bypass surgery : Pasternak R, Cohn K, Selzer A, Langston MF Jr: Am J Med 58: 166–170, 1975

Enhanced rate of progression of coronary artery disease following aortocoronary saphenous vein bypass surgery : Pasternak R, Cohn K, Selzer A, Langston MF Jr: Am J Med 58: 166–170, 1975

Enhanced rate of progression of coronary artery disease following aortocoronary saphenous vein bypass surgery

To evaluate the fate of the coronary arteries after aortocoronary bypass, 40 patients underwent serial selective coronary angiographic studies 1 year apart, and the frequency of progression of coronary artery disease was estimated. Thirty-two had saphenous vein bypass surgery after the first procedure, six had Vineberg operations, and two had no interim operation. In each patient, the right, left, anterior descending and circumflex coronary arteries (including their branches) were separately evaluated. Progressive narrowing was evident in 31 of 50 (62 per cent) bypassed vessels and in only 11 of 113 (9.7 per cent) nonbypassed arteries (p < 0.001). Coronary arteries with moderate to severe obstruction initially (50 to 99 per cent occluded) manifested progressive disease more frequently (33 of 70 arteries) than did arteries that were normal or mildly narrowed initially (4 of 71) (p < 0.001). Considering only those vessels with 50 to 99 per cent obstruction initially, 27 of 35 (77 per cent) of the bypassed arteries and only 6 of 35 (17 per cent) of the nonbypassed arteries showed progression (p < 0.001). We conclude that moderately or severely narrowed coronary arteries are more likely to show progressive narrowing than normal or mildly obstructed ones and that progression of coronary disease is greater in bypassed vessels than in nonbypassed vessels. In view of potential graft closure, the implications of these findings must be considered in selecting patients for aortocoronary bypass.

Evaluation of the Immediate Effect of Aortocoronary Saphenous Vein Bypass Surgery on Myocardial Contractility

In order to evaluate the immediate effects of aortocoronary saphenous vein bypass graft surgery on myocardial contractility, studies were carried out in 24 patients with severe occlusive disease of the right or left coronary arteries or both. Myocardial contractility was expressed by the extrapolated maximal velocity of contractile elements shortening (Vmax) and peak (dP/dt)/KP (Vpm) as calculated from the left ventricular pressure and its rate of pressure rise, dP/dt by employment of a needle connected transducer. Studies were made with the patient in sinus rhythm and a stable circulation and no cardiac action drug administration before and after saphenous vein bypass surgery. The patients were divided into two groups: group 1 (12 patients) were those without LV aneurysm and satisfactory myocardial contractility (Vmax 1.40±0.07 and Vpm 1.08±0.06 muscle lengths per second), and group 2 consisted of 12 patients with poor initial myocardial contractility (Vmax±standard error 0.94±0.05 and Vpm 0.74±0.05 muscle lengths per second) and LV aneurysm. In group 1 patients there was a significant increase in Vmax and Vpm values from preoperative results (Vmax±standard error 1.84±0.09 and Vpm 1.39±0.07 muscle lengths per second (p<0.0025 and p<0.0025, respectively)). Group 2 patients did not show any significant change in Vpm values (Vpm±standard error 0.80±0.07 muscle lengths per second, p<0.35) and only a slight change in Vmax (Vmax 1.02±0.07, p<0.0125), but five out of 12 of the changes were negative (Table 5). These preliminary data indicate that increased blood supply to the myocardium delivered by aortocoronary saphenous vein bypass graft surgery is beneficial and increase myocardial contractility in those patients with good preoperative contractility.

Recurrent Ventricular Fibrillation

Four episodes of ventricular fibrillation refractory to medical therapy occurred in a patient with increasingly severe angina pectoris. Coronary arteriography showed 90% stenosis of the left main coronary artery. After emergency aortocoronary saphenous vein bypass surgery, the patient had no further episodes and has felt well during a 17-month follow-up period. Such surgery should be considered in patients with coronary disease in whom life-threatening arrhythmias develop. (JAMA228:70-72, 1974)

Recurrent ventricular fibrillation. Treatment by emergency aortocoronary saphenous vein bypass.

Four episodes of ventricular fibrillation refractory to medical therapy occurred in a patient with increasingly severe angina pectoris. Coronary arteriography showed 90% stenosis of the left main coronary artery. After emergency aortocoronary saphenous vein bypass surgery, the patient had no further episodes and has felt well during a 17-month follow-up period. Such surgery should be considered in patients with coronary disease in whom life-threatening arrhythmias develop. (JAMA228:70-72, 1974)

The incidence and clinical significance of ECG-VCG changes of myocardial infarction following aortocoronary saphenous vein bypass surgery

The electrocardiogram and vectorcardiogram were analyzed in 35 consecutive patients before and after undergoing elective aortocoronary saphenous vein bypass grafting for angina pectoris. Typical changes of perioperative myocardial infarction were seen in 40 per cent (ECG) and 46 per cent (VCG). Changes of ST segments and T wave could not be correlated with QRS changes of infarction. Surgery with or without infarction resulted in a loss in R wave voltage in anterior and lateral precordial leads (V 4, V 5, and V 6) as well as in a symmetric shrinkage of the vector loop in the transverse and frontal planes. Comparing one year follow-up results of those with versus those without perioperative VCG changes of infarction showed that late death, clinical evidence of myocardial damage, and reinfarction were more frequent in the infarction group. However, no difference in N.Y.H.A. functional classification, congestive heart failure alone, or persistence of angina pectoris could be demonstrated between the two groups. The ECG and VCG changes of perioperative infarction are common with this operation and helped to predict late morbidity and death.

Life-threatening ventricular arrhythmias induced by exercise: Cessation after coronary bypass surgery

In three patients with clinical ischemic heart disease ventricular tachycardia developed during standard exercise testing. Despite suppressive antiarrhythmic therapy, ventricular tachycardia during exercise persisted in one patient; ventricular fibrillation requiring cardiopulmonary resuscitation developed in the other two. Coronary angiography revealed significant obstructive coronary artery disease with no ventricular aneurysm in all three patients. Aortocoronary saphenous vein bypass surgery was performed successfully without electrocardiographic or clinical evidence of intraoperative myocardial infarction. Postoperative cineangiography documented graft patency, and repeated exercise testing failed to elicit any ventricular irritability in these patients. They have remained asymptomatic with no antiarrhythmic therapy for up to 2 years postoperatively.

What is the relationship between the response of angina to coronary surgery and anatomical success?

Analysis of clinical response, graft patency, and treadmill performance was carried out in 72 patients one year after aortocoronary saphenous vein bypass surgery. Thirty-four of 46 patients with complete relief of angina had all grafts patent at one year, as opposed to 4 of 14 unimproved patients ( P &lt; 0.01); 84.4% of 77 grafts in the former group were patent, as compared with 48% of 25 grafts in the latter group ( P &lt; 0.01). Similarly, treadmill tolerance and end-exercise heart rate were significantly increased in patients experiencing significant or complete clinical relief. Unimproved patients showed no improvement in these parameters. Individual observations indicated that graft patency did not always ensure clinical relief or abolition of ischemic treadmill responses.

Cardiac function assessed by systolic time intervals after aortocoronary saphenous vein bypass surgery.

Cardiac function assessed by systolic time intervals after aortocoronary saphenous vein bypass surgery.

Influence of aortocoronary saphenous vein bypass surgery on left ventricular volumes and ejection fraction: Comparison before and one year after surgery in 51 patients

Ventricular volumes and ejection fraction were studied by single plane cineventriculography before and one year after vein bypass graft surgery in 51 patients. Selective opacification of the grafts was performed two to three weeks and one year after surgery. In 23 patients with patent grafts without stenosis or with ≤50 per cent stenosis, left ventricular end-diastolic volume, end-systolic volume and ejection fraction were unchanged (p always < 0.3). Unchanged ventricular volume and ejection fraction were also observed in nine patients with double grafts of which one was occluded and the other patent. However, in 19 patients with occluded or severely stenosed grafts, a significant increase in end-diastolic volume (p < 0.05) and end-systolic volume (p < 0.01), and a decrease in ejection fraction (p < 0.05) were found. The variation in ejection fraction was different between patients with grafts to the left anterior descending and to the right coronary artery (p < 0.025). In conclusion, there was no significant improvement in ventricular volume and ejection fraction in patients with patent grafts whereas deterioration was evident after unsuccessful surgery but only to the left anterior descending coronary artery. This lack of improvement in ventricular performance in the presence of patent grafts and the deleterious effect of graft occlusion should promote continuing objective and critical evaluation of this type of surgery.