Timothy Takaro

Observer agreement in evaluating coronary angiograms.

The reliability of interpretation of coronary arteriography as a diagnostic tool was investigated in a sub study of the VA Cooperative Study of Surgical Treatment for Coronary Arterial Occlusive Disease. Twenty two physicians with varying levels of experience read 13 cine angiograms — blind — on two different oc casions. Analysis of inter- and intraobserver variability showed that angiographic items about which observers were most inconsistent from one reading to the other had the largest interobserver disagreement as well. They were the distal portions of the left anterior descending and left circumflex arteries. Among the items on which there was most consistent agreement — namely, the right main coronary artery and presence of ven tricular aneurysm — there was most often agreement between observers as well. When individual readers were evaluated, some observers were far more consistent in their own readings of all the angiographic items than others. This intraobserver agreement in turn correlated fairly well with how often they agreed with the other observers and with how much experience they reported having in reading coronary cineangiograms.

Treatment of chronic stable angina. A preliminary report of survival data of the randomized Veterans Administration cooperative study.

We evaluated the effect of saphenous-vein-bypass grafting on survival in patients with chronic stable angina by comparing medical and surgical treatment in a large-scale, prospective randomized study. Excluding patients with left-main-coronary-artery disease who have already been reported, a total of 596 patients were entered into this study; when randomized into a medical group (310 patients) and a surgical group (286 patients), entry clinical and angiographic base lines were comparable. Operative mortality at 30 days was 5.6 per cent. At an average of one year after operation, 69 per cent of all grafts were patent, and 88 per cent of the surgical patients had atleast one patent graft. There was no statistically significant difference in survival, at a minimal follow-up interval of 21 months, between patients treated medically and those treated with saphenous-vein-bypass grafting. At 36 months, 87 per cent of the medical group and 88 per cent of the surgical group were alive.

Effect of bypass surgery on survival in patients in low- and high-risk subgroups delineated by the use of simple clinical variables.

A multivariate risk function was developed on data from all 508 medical patients in the Veterans Administration (VA) randomized study of coronary bypass surgery. The variables, in order of importance, were ST-segment depression on resting ECG, history of myocardial infarction, history of hypertension and New York Heart Association functional classification III or IV. These noninvasive variables have been reported to be risk factors in natural-history studies of coronary heart disease (CHD). Applying the risk function to medical and surgical patients of the 1972–1974 cohort yielded a 5-year probability of dying for each patient. Investigation of treatment effects in approximate terciles obtained by collapsing the probability distribution into low-, middle- and high-risk groups showed that surgery was beneficial for patients in the high-risk tercile even after removal of patients with left main coronary artery disease (17% surgical vs 34% medical mortality at 5 years; p < 0.01). This finding was accentuated when patients in the 10 hospitals with the lowest operative mortality (3.3%) were compared. Mortality results in the low-risk tercile favored medical treatment (medical vs surgical mortality 7% vs 17%; p < 0.05).The risk function predicted mortality well not only for the VA medical group, but also for an independent symptomatic CHD population from the University of Alabama arteriography registry.This report further delineates the advantages and limitations of coronary bypass surgery in CHD patients with chronic stable angina.

The Veterans Administration Cooperative Study of stable angina: current status.

The current status of the Veterans Administration Cooperative Study of the effect of surgery on survival in patients with stable angina is presented. The outcome in 686 adult miles randomly allocated to medical or surgical treatment groups in 1972-1974 was studied in subgroups of patients classified by invasive (arteriographic) and noninvasive risk factors. In 91 patients with left main lesions reducing the luminal diameter 50% or more, surgery signiflcantly improved survival in the two-thirds characterized as middle or high risk by four simple noninvasive predictors of prognosis (New York Heart Association functional classification III or IV, history of myocardial infarction, history of hypertension, and ST-segment depression on the resting baseline ECG as assessed on a centralized reading). Patients with three-vessel disease and no significant disease of the left main coronary artery also had better survival rates when treated surgically. However, this was statistically significant at 6 years only in the 10 hospitals in which the aggregate operative mortality was 3.3%. Patients without left main lesions were also categorized by four noninvasive predictors of risk. Categorizing such patients into roughly equal groups of high, middle, and low risk identifieid a high-risk group, in which surgery was associated with statistically improved survival, and low- and middle-risk groups in which it was not. The use of both invasive and noninvasive factors to assess risk in patients with chronic stable angina pectoris provided greater predictive power than either angiography or noninvasive factors alone.

Ten-year incidence of myocardial infarction and prognosis after infarction : department of veterans affairs cooperative study of coronary artery bypass surgery

BackgroundThe 10-year incidence of myocardial infarction (fatal and nonfatal) and the prognosis after infarction were evaluated in 686 patients with stable angina who were randomly assigned to medical or surgical treatment in the Veterans Administration Cooperative Study of Coronary Artery Bypass Surgery. Methods and ResultsMyocardial infarction was defined by either new Q wave findings or clinical symptoms compatible with myocardial infarction accompanied by serum enzyme elevations with or without electrocardiographic findings. Treatment comparisons were made according to original treatment assignment; 35% of the medical cohort had bypass surgery during the 10-year follow-up period. The overall cumulative infarction rate was somewhat higher in patients assigned to surgery (36%) than in medical patients (31%) (p = 0.13) due to perioperative infarctions (13%) and an accelerated infarction rate after the fifth year of follow-up (average, 2.4%Y/yr in the surgical group versus 1.4%/yr in the medical group). The 10-year cumulative incidence of death or myocardial infarction was also higher in surgical (54%) than in medical (49o) patients (p = 0.20). According to the Cox model, the estimated risk of death after infarction was 59% lower in surgical than in medical patients (p<0.0001). The reduction in postinfarction mortality with surgery was most striking in the first month after the event: 99% in the first month (p<0.0001) and 49% subsequently (p<0.0001). The estimated risk of death in the absence of infarction was nearly identical regardless of treatment (p = 0.75). Exclusion of perioperative infarctions did not alter the findings. ConclusionsAlthough surgery does not reduce the incidence of myocardial infarction overall, it does reduce the risk of mortality after infarction, particularly in the first 30 days after the event (fatal infarctions). (Circulation 1991;83:747–755

Carotid Sinus Nerve Stimulation Treatment of Angina Refractory to Other Surgical Procedures

Abstract Carotid sinus nerve (CSN) stimulators were inserted in 13 patients with intractable angina pectoris following surgical procedures to increase myocardial blood flow and relieve their angina. In all patients the CSN stimulation assisted to some degree in relieving angina. In some, a variation of the stimulation level and pattern was necessary to relieve chest pain. Digitalis, diuretics, long-acting vasodilators, and occasionally narcotics, beta-adrenergic-receptor blocking agents, and nitroglycerin were necessary to control angina. The CSN stimulator is a useful adjunct to drug therapy in controlling angina pectoris. In 10 patients square-wave electromagnetic flow probe measurements showed a 21% decrease in bilateral common carotid artery blood flow during CSN stimulation. One of 3 patients with asymptomatic carotid arteriosclerotic plagues sustained a transient cerebrovascular accident following stimulator implantation. CSN stimulators are not recommended for patients with signs or symptoms of cerebrovascular disease because of the danger of cerebral embolization and reduction in cerebral blood flow during stimulation.

Use of a Lung Stapler in Pulmonary Resection

lthough the results of pulmonary resection by standard techniques are good, there is a continuing need for, and interest in, A refinements in these techniques [5, 8, 141. There are two main areas of concern. The first is the control of blood and air leakage from the nonpleural surfaces after sublobar resection. The second is the elimination of the small but persistent number of bronchopleural fistulas. The mechanical stapler here described has been effective in our experience in approaching attainment of both objectives. A report from this hospital [15] on the use of the Russian UKB-25 stapler, formerly employed, indicated that it had some advantages but did not produce the marked improvement over previous techniques of bronchial closure that had been anticipated. The UKB-25 stapler lays down a single row of staples with the long axis of the staples parallel to the long axis of the bronchus. This report is on the use of the Russian stapler UKL-40,* which

Esophagopleural Fistula Following Pulmonary Resection

The development of esophagopleural fistula following pulmonary resection is an uncommon but serious complication. The fistula may appear either soon after operation, due to direct trauma to the esophagus or to its blood supply during extensive dissection, or later, in association with the development of a bronchopleural fistula and empyema following the pulmonary resection. Treatment of these fistulas is usually complicated, and the recovery period is prolonged. Control of infection, hyperalimentation, obliteration of the empyema space, and closure of the fistula with a muscle or pleural flap are recommended methods of management. The pathogenesis, treatment, results, and prevention of this complication are discussed.

Five-year effect of medical and surgical therapy on resting left ventricular function in stable angina: Veterans administration cooperative study

The effect of coronary artery bypass grafting (CABG) and medical therapy on 5-year resting left ventricular (LV) function was studied in 194 randomized patients with stable angina in the Veterans Administration Study of Coronary Artery Bypass Surgery. LV ejection fraction (EF) was determined in a central laboratory. The 92 medical and 102 surgical patients were comparable at entry with respect to historic, angiographic and electrocardiographic prognostic indicators. Twenty-eight percent of the medical and 30% of the surgical patients had a baseline EF of less than 50%. There was no significant change in mean EF between baseline and 5-year values in either treatment group. The baseline and 5-year values were 56 and 58% in each treatment group. Intervening myocardial infarction (MI) had an adverse effect in medically treated patients (59 to 46%, p less than 0.01) and in surgically treated patients with late MI (58 to 47%, difference not significant). Perioperative MI was not associated with a decrease in EF (56 to 58%, difference not significant). These findings extend the similar results of previous short-term studies of the effect of coronary bypass surgery on resting LV function to 5 years, and provide data in a comparable medical control group.

Quality Control for Cardiac Surgery in the Veterans Administration

The volume of cardiac surgical procedures and the 30-day mortality associated with them were reviewed for the total experience of 72 Veterans Administration medical centers over a 10-year period (1975 to 1984). The total number of cardiopulmonary bypass operations increased from 3,074 in 1975 to 6,455 in 1984, whereas operative mortality declined from 8.3 to 4.7%. Operative mortality associated with isolated valve replacement operations declined from 10.9 to 5.9%. Aortocoronary vein bypass operations, which increased in number from 1,679 to 4,988 over the 10-year period, were associated with an operative mortality of 4.7% in 1975 and 3.6% in 1984. The extent of the patients disease accounted for most of the operative mortality, but problems related to the adequacy of myocardial protection and the surgical technique were also important factors. These data were compared with similar comprehensive statistics compiled by the New York State Department of Health over a five-year period (1979-1983). Operative mortality rates were quite similar for aortocoronary bypass procedures, mitral valve replacements, and total cardiac operations. However, operative mortality for aortic valve procedures was higher among the Veterans Administration hospitals. In the future, if operative risk factors are clearly defined, a more meaningful comparison of operative mortality among ongoing reviews, such as those being carried out by the Veterans Administration and by New York State, could be used to establish standards of performance for cardiac surgery.