Greater Stenosis Research Articles

Occlusive thromboaortopathy (Takayasu's disease): cervical arterial stenoses, retinal arterial pressure, retinal microaneurysms and prognosis.

Eighty-one young Japanese patients with occlusive thromboaortopathy (Takayasu's disease) were classed into three groups according to the degree and extent of diameter stenosis in the 4 cervical arterial systems, as determined by serial aortography. Class I was made up of 63 patients with 70% or greater stenosis in less than 3 systems, including 33 patients without systemic hypertension (Class Ia). Class II was made up of 6 patients with 70% or greater stenosis in 3 systems and less than 50% stenosis in the remaining 1, including 5 patients without systemic hypertension (Class IIa). Class III was up of 12 patients with 70% or greater stenosis in 3 systems and 50% or greater stenosis in 1 system. Ophthalmodynamometric systolic pressure in patients in Class III was significantly lower than that in patients in Class IIa (p less than 0.001), but there was no significant difference between patients in Classes Ia and IIa. Microaneurysms and/or arteriovenous anastomoses in the retinal vessels were found in all but one patient in Class III and in only one patient in combined Classes I and II. These results indicate that each of the ophthalmodynamometric values and fundoscopic findings are very helpful in identifying the markedly severe occlusive lesions (Class III) of the 4 cervical arterial systems. In this chronic disease, however, angiography is most useful for evaluation of these severe lesions, to monitor progression from Classes I and II to Class III, in which the prognosis is rather poor.

Clinical factors predicting successful electrophysiologic-pharmacologic study in patients with ventricular tachycardia

Data from 142 patients who had sustained ventricular tachycardia or ventricular fibrillation were analyzed to determine if clinical variables predict response to antiarrhythmic drugs at electrophysiologic study. Effective antiarrhythmic drugs were identified for 43 patients (30%). Ten of 25 variables analyzed were univariate predictors of drug response at the probability (p) level of less than 0.05. Stepwise logistic regression identified three variables independently predictive of drug response: fewer coronary arteries with 70% or greater stenosis (p less than 0.001), female sex (p less than 0.002) and fewer episodes of arrhythmia (p less than 0.03). A function incorporating these three variables was constructed to predict the probability of drug response, and ranges of the predictor function corresponding to high, intermediate and low probabilities of drug response were identified. Response rates in the high (greater than 50%), intermediate and low (less than 10%) probability ranges were 28 (58%) of 48, 10 (27%) of 37 and 5 (9%) of 57, respectively. Thus 40% of the patients who had a less than 10% likelihood of benefit from electrophysiologic-pharmacologic study were classified into the low probability range. When the predictor function was applied prospectively to 25 additional patients, response rates in the three probability ranges were 3 (50%) of 6, 1 (12%) of 8 and 0 (0%) of 11. These data show that analysis of clinical variables can be used to estimate the probability of benefit from electrophysiologic-pharmacologic study.

Postoperative Treadmill Performance and Graft Patency after Myocardial Revascularization

In a prospective study, a random selection of 122 patients who had coronary artery bypass grafting were studied angiographically and given treadmill tests preoperatively and one year after operation, regardless of their symptoms. A total of 397 grafts were performed (average, 3.3 grafts per patient) on all primary and secondary coronary vessels deemed graftable. Complete coronary revascularization (grafts to vessels 1.5 mm or more in diameter with 50% or greater stenosis) was achieved in 104 patients (85%); 18 patients (15%) were considered incompletely revascularized. One hundred sixteen of the 397 grafts (29%) were to the left anterior descending (LAD) coronary artery, 99 (25%) to the right coronary artery, 126 (32%) to the obtuse marginal branch, 52 (13%) to the diagonal branch of the LAD coronary artery, and 4 (1%) to the septal coronary arteries. Overall results showed that patients with positive postoperative treadmill tests had a graft patency of 64%, compared with 86% for patients with negative treadmill tests ( p < 0.001). Completely revascularized patients with all grafts patent had a 4.8% (3/62) incidence of positive treadmill performance, compared with 60% (6/10) for incompletely revascularized patients with all grafts patent ( p < 0.001). Completely revascularized patients with positive treadmill tests had a graft patency of 58% (45/78), while those with negative treadmill evaluations had a graft patency of 86% (227/264) ( p < 0.001). The patency rate for incompletely revascularized patients with positive treadmill performance was 78% (25/32) and 87% (20/23) for those with negative treadmill performance. This difference was not statistically significant. This study shows that postoperative treadmill performance is highly dependent on completeness of revascularization and graft patency. It therefore supports the prognostic importance of regular treadmill exercise testing to monitor continued graft patency.

LONG-TERM RESULTS OF PROSPECTIVE RANDOMISED STUDY OF CORONARY ARTERY BYPASS SURGERY IN STABLE ANGINA PECTORIS: European Coronary Surgery Study Group

This report presents the final results (follow-up 5-8 years) of a prospective study in 768 men aged under 65 with mild to moderate angina, 50% or greater stenosis in at least two major coronary arteries, and good left ventricular function. 395 were randomised to coronary artery bypass surgery, 373 to no treatment; 1 patient in the surgery group was lost to follow-up. These original groups were compared, whatever subsequently happened to the patients. Survival was improved significantly by surgery in the total population, in patients with three-vessel disease, and in patients with stenosis in the proximal third of the left anterior descending artery constituting a component of either two or three vessel disease, and non-significantly in patients with left main coronary disease. An abnormal electrocardiogram at rest, ST-segment depression ≽1·5 mm during exercise, peripheral arterial disease, and increasing age independently point to a better chance of survival with surgery. In the absence of these prognostic variables in patients with either two or three vessel disease the outlook is so good that early surgery is unlikely to increase the prospect of survival. In terms of anginal attacks, use of beta-adrenergic blockers and nitrates, and exercise performance the surgical group did significantly better than the medical group throughout the 5 years of follow-up, but the difference between the two treatments tended to decrease.

Anatomic and prognostic implications of an early positive treadmill exercise test

Eighty men (group A) with clinical coronary artery disease underwent coronary angiography regardless of symptoms and previous therapy because they had a positive treadmill exercise test in stage I or II of the Bruce protocol. Thirty-four other men (group B) who also had an early positive treadmill test underwent coronary angiography because they had disabling angina pectoris despite medical therapy. We found left main coronary artery stenosis of 50% or greater of the vessel diameter in 28% of group A and 35% of group B (p >0.3). In contrast, only 10% of 93 other catheterized patients who had treadmill tests that were not early positive had left main coronary disease (p < 0.001). Fifty-four patients from group A who did not have left main stenosis of 50% or greater were treated medically. In this subgroup, 85% had 2 or 3 major coronary vessels with 75% or greater stenosis. These patients had a 36 month survival rate of 89.2%. We conclude that an early positive treadmill test identifies patients who have an increased likelihood of having left main coronary stenosis, even if they are minimally symptomatic. To identify left main coronary stenosis, catheterization may be justified in patients whose angina pectoris has been mild or not intensively treated when they have an early positive treadmill response. After left main coronary stenosis has been excluded, these patients may be treated medically with a low mortality.

Scintigraphic detection of carotid atherosclerosis with indium-111-labeled autologous platelets.

Using autologous platelets labeled with indium-111-oxine, we studied the localization of platelets on arterial lesions by radionuclide scintigraphy in 34 patients with suspected cerebrovascular disease. The imaging results were compared with the findings of contrast angiography in 23 patients, 16 of whom were receiving antiplatelet and/or anticoagulant drugs during the platelet imaging study. Angiography demonstrated atherosclerotic lesions at 33 sites in the extracranial arteries of 16 of these patients. There was accumulation of 111In-platelets at 20 of these sites (61%) and at three other sites without definite angiographic abnormalities. Lesions with stenoses less than 50% were slightly more frequent than those with greater stenosis (68% vs 45%). The frequency of true-positive scintigraphic results was slightly higher in patients not treated with antithrombotic agents than in those on such drugs (70% vs 57%). Our results suggest that imaging with 111In-labeled autologous platelets may be useful for evaluating the pathophysiologic characteristics of atherosclerotic lesions in patients with cerebrovascular disease.

Factors influencing the diagnostic sensitivity of the exercise test in coronary artery disease.

A continuous multistage bicycle ergometer test was performed on 50 patients with coronary artery disease. Selective cinecoronary angiography and left ventriculography were performed within a week of the test in all patients. Overall, 62% had a positive ischemic response, defined as 1 mm or greater depression of the ST segment. Patients with 75% or greater stenosis in any vessel and those with triple-vessel involvement had a higher incidence of positive tests. Those with low systolic ejection fractions and areas of asynergy had fewer positive tests than patients with normal ejection fractions and normal or minimal segmental wall motion abnormalities. The level of exercise, location of arterial disease and the presence of collateral blood supply to the diseased vessels did not appear to influence the sensitivity of the exercise stress test.

冠動脈硬化症における血清脂質およびアポ蛋白レベルの検討

Determination of serum lipids (TC, TG and HDL-TC) and apolipoprotein (apo A-I, A-III, B, C-I, C-II, C-III and E) levels and disc gel electrophoresis of serum lipoproteins were performed in 46 patients of coronary hearts disease and their 43 roughly-age-matched controls. Coronary heart disease (CHD) group with mean age of 61 years old had 75% or greater stenosis in one or more major coronary arteries. Among them 28 patients were suvivors of acute myocardial infarction which occured not less than 12 months before the study. Controls with mean age of 62 years old showed no evidence of significant stenosis in major vessels on selective arteriography. All female patients experienced menopause at least 5 years before the study.Serum levels of apo A-I, A-II, B, C-II, C-III and E were determined by electroimmunoassay and apo C-I by radial immunoassay. HDL was isolated by precipitating VLDL and LDL with heparin-manganese chloride and cholesterol (HDL-TC) was measured. Following results were obtained: (1) CHD group showed significantly higher levels of TC, HDL-TC apo A-I, apo C-I, apo C-II and ratio of (TC-HDL-TC)/HDL-TC and apo B/apo A-I than those of control group. (2) midband lipoprotein was detected in 54% of CHD group and 30% of control group; the difference of frequency was statistically significant. Serum lipid and apolipoprotein levels, however, did not correlate with the presence of midband lipoprotein.(3) Levels of apo C-I, C-II, C-III and E showd highly significant correlation with those of TC and TG.(4) In CHD group, survivors of acute myocadial infaction had significantly lower levels of HDL-TC, ratio of (TC-HDL-TC)/HDL-TC and apo B/apo A-I than those who had no history of myocardial infarction which may imply that LDL/HDL ratio was one of the important factor for the development of myocardial infarction.

Plasma lipoproteins and coronary arteriography in subjects in the program on the surgical control of the hyperlipidemias: Preliminary report

Coronary arteriographic findings, plasma lipid and lipoprotein levels, and cigarette smoking history are reported for the first 101 male post myocardial infarction survivors who have been entered into the POSCH clinical trial. Estimates of the extent of stenosis in the major coronary arteries were made using 4 models ranging from a simple determination of the number of the 3 major vessels having significant (i.e. 50% or greater stenosis) disease to more complex methods of determining overall extent of disease in 14 major segments of the coronary arteries. Age was shown to be an important factor in the extent of vessel disease. When controlling for age, plasma cholesterol and LDL-cholesterol levels were shown to be related to the extent of disease, especially in Type II hyperlipoproteinemia subjects. Multiple linear regression analysis demonstrated that age and LDL-cholesterol had positive associations and HDL-cholesterol had an inverse association with the coronary artery disease indices. In this comparatively “healthy” subgroup of the overall population of first MI survivors the major CHD risk factors are limited to plasma lipids and cigarette smoking. This preliminary report of 10% of the recruitment objective of the project supports the currently held views of the lipid—atherosclerosis hypothesis regarding the effects of age, total plasma cholesterol, LDL-cholesterol, and HDL-cholesterol on the extent of coronary atherosclerotic plaques, as determined by coronary arteriography.

Coronary arterial surgery in patients with incapacitating angina pectoris and myxedema

Patients with severe angina pectoris and untreated myxedema pose a clinical dilemma because angina may be exacerbated by thyroid hormone replacement therapy, the usual medical management of angina may be ineffective or even dangerous and invasive diagnostic procedures (cardiac catheterization) and surgery have generally been thought to be contraindicated in myxedema. Because of incapacitating progressive angina refractory to medical management, six patients (mean age 58 years) with severe hypothyroidism (mean serum thyroxine level 0.66 μg/100 ml, normal 4 to 11) underwent selective coronary angiography and quantitative biplane left ventriculography. All patients tolerated cardiac catheterization without complication. Five of the six patients had 70 percent or greater stenosis in three coronary vessels, including three patients with left main coronary artery disease. Coronary revascularization was recommended to each patient. One patient refused surgery and subsequently died suddenly. Another patient was scheduled for elective surgery but in the interim died of a massive acute anterior infarction. Four patients underwent saphenous vein bypass grafting to a mean of 2.8 vessels without complication. Preoperative thyroid hormone replacement ranged from 0 to 50 μg of L-thyroxine daily. Postoperatively adequate thyroid hormone replacement was administered to all patients without complication. At follow-up, a mean of 18 months postoperatively, each of the four operative patients is euthyroid, and all have noted either complete resolution or marked amelioration of their angina. It is concluded that (1) patients with incapacitating angina and myxedema often have severe coronary artery disease; (2) cardiac catheterization can be performed safely in the absence of thyroid replacement; (3) coronary revascularization surgery can be performed safely with minimal thyroid replacement; (4) full thyroid replacement can be safely achieved during the postoperative period.

Correlation of computer-quantitated treadmill exercise electrocardiogram with arteriographic location of coronary artery disease

Graded treadmill exercise testing and coronary cinearteriographic studies were carried out on 86 patients with angina pectoris. At rest, all patients demonstrated a normal S-T segment on the modified bipolar lead V 5 recording used. The computer-quantitated S-T segment response to exercise was correlated with the location and extent of obstructive coronary artery disease. The coronary cineartertograms were reviewed by 3 physicians and stenosis of 75 percent or greater was considered significant. All patients showed at least this degree of stenosis in 1 or more major coronary arteries, and 83 of 86 exhibited 90 percent or greater stenosis in at least 1 artery. Thirty-one patients had stenosis in a single artery, 43 had stenosis in 2 arteries and 12 had significant lesions in all 3 major arteries. In 70 of the 86 (82 percent) patients, a positive S-T segment response developed during or immediately after exercise. In 12 of the 16 with a negative response, disease was limited to a single artery. In 11 of the 12 the disease was restricted to the right coronary or left circumflex arteries. Of the 12 patients with an isolated stenosis of the left anterior descending artery, 11 (92 percent) had a positive S-T segment response. Of 55 patients with 2- or 3-vessel disease, 51 (93 percent) demonstrated a positive S-T response. Graded treadmill exercise testing in 80 patients with chest pain, normal coronary art eriograms and normal left ventricular function revealed 4 (5 percent) with a false positive S-T segment response. The possible mechanisms underlying the high incidence of false negative exercise electrocardiographic tests in patients with disease isolated to the right coronary or left circumflex artery are discussed.