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Biomedical subjects

K B Davis

Publications and source records attributed to K B Davis.

At least 73 records · Page 4Linked to original sources
PubMed1985

A randomized trial of coronary artery bypass surgery. Survival of patients with a low ejection fraction.

The Coronary Artery Surgery Study (CASS) was designed to compare medical and surgical treatment of selected patients with chronic, stable coronary artery disease. This report concerns a subset of patients with reduced ventricular function. Of 780 patients randomly assigned to medical or surgical treatment, 160 had ejection fractions above 0.34 but below 0.50 at base line and have been followed for an average of seven years. Eighty-two patients were assigned to medical therapy, and 78 to surgery; the two groups were comparable at base line with regard to prognostically important variables. At seven years, 84 per cent of patients in the surgical group were alive, as compared with 70 per cent of the medical group (P = 0.01). Nearly half the patients with impaired ventricular function had triple-vessel disease at entry; at seven years, observed survival in this group was 88 and 65 per cent for those assigned to surgical and medical treatment, respectively (P = 0.009). Survival of patients with single-vessel or double-vessel disease was similar in the two treatment groups. We conclude that patients with triple-vessel disease and ejection fractions higher than 0.34 but lower than 0.50 appear to have improved seven-year survival with elective bypass surgery.

Cardiac Output↗
PubMed1985

The western Washington randomized trial of intracoronary streptokinase in acute myocardial infarction. A 12-month follow-up report.

After cardiac catheterization and coronary arteriography, 134 patients who had had an acute myocardial infarction were randomly assigned to treatment with intracoronary streptokinase (4000 U per minute, begun approximately 4 1/2 hours after the onset of symptoms, for a total of 286,000 +/- 77,800 U over 72 +/- 24 minutes); 116 control patients received standard care after they returned to the coronary care unit, immediately after angiography. Preliminary results of this trial have been published in the Journal (1983; 309:1477-81). During the first 30 days, 5 deaths occurred in the streptokinase group and 13 occurred in the control group (3.7 vs 11.2 per cent, P = 0.02); during the first year, the corresponding figures were 11 and 17 deaths (8.2 vs. 14.7 per cent, P = 0.10). However, when a minor imbalance in the ejection fraction and infarct location between the two groups was adjusted by logistic regression, the difference in one-year mortality became significant (P = 0.03). In the streptokinase group, 2 of the 80 patients in whom perfusion was reestablished (2.5 per cent) had died by one year, whereas 3 of the 13 with partial reperfusion (23.1 per cent) and 6 of the 41 with no reperfusion (14.6 per cent) had died (P = 0.008). Mortality among patients with partial reperfusion was not significantly different from that among those without reperfusion (P greater than 0.90). No base-line clinical, angiographic, or hemodynamic variable was predictive of successful reperfusion, according to univariate and multivariate analyses. We conclude that intracoronary streptokinase reduces one-year mortality among patients with acute myocardial infarction, but this improvement occurs only among those in whom thrombolysis results in coronary artery reperfusion.

Coronary Angiography↗
PubMed1985

The psychological ecology of the neglectful mother.

Interviews were conducted with 152 neglectful mothers and with 154 non-neglectful, who were matched on race, economic status, urban/rural status and other life circumstances. The neglectful mothers reported less support available from informal networks; they also described their neighborhoods as less friendly and helpful than did the controls. However, the conclusion that neglect is related to living in settings that are socially impoverished was not supported by independent interviews with neighbors. Rather, it appeared that neglectful mothers are often isolated by those around them. Because they are seen as deviant and unlikely to reciprocate help, they do not have access to such support as there may be in their ecology. A new model is presented for preventive, community-based intervention, based on the findings of the research.

Child↗
PubMed1985

A test of the National Death Index using the Coronary Artery Surgery Study (CASS).

The National Death Index (NDI) is a central, computerized index of death record information compiled from records submitted by the Vital Statistics Office of each state to the National Center for Health Statistics. A selection of 1180 cases, including 370 decedents, from the Coronary Artery Surgery Study was sent to the NDI to test the reliability of the index in identifying decedents. Five possible matching rules are considered: an NDI match with soundex included, an NDI match without soundex matches, an NDI match on social security number, an NDI match on personal data (first name, last name, sex, race, and month, day, and year of birth), and an NDI match on social security number or personal data. In determining death, the greatest positive predictive value was given by a match on social security number, while the greatest negative predictive value was given by an NDI match with soundex included. Further comparisons of sensitivity and specificity, and figures that relate predictive values to the population mortality rate, are given to assist potential users in determining an optimal matching rule.

Coronary Disease↗
PubMed1985

Late effects of intracoronary streptokinase on regional wall motion, ventricular aneurysm and left ventricular thrombus in myocardial infarction: results from the Western Washington Randomized Trial.

To determine whether intracoronary streptokinase improves late regional wall motion or reduces left ventricular aneurysm or thrombus formation in patients with acute myocardial infarction, two-dimensional echocardiography was performed at 8 +/- 3 weeks after infarction in 83 patients randomized to streptokinase (n = 45) or standard therapy (n = 38) in the Western Washington Intracoronary Streptokinase Trial. Among the patients treated with streptokinase, the average time to treatment was 4.7 +/- 2.5 hours after the onset of chest pain, and 67% had successful reperfusion. Regional wall motion was assessed in nine left ventricular segments on a scale of 1 to 4 (normal, hypokinetic, akinetic and dyskinetic). Left ventricular thrombus formation was interpreted as positive, equivocal or negative. All patients received anticoagulant therapy in the hospital and 52 received such therapy after hospital discharge. The mean (+/- SD) global (1.5 +/- 0.4 in both groups) and regional wall motion scores in the streptokinase-treated and control groups were not significantly different. The prevalence of aneurysm was 16% in both groups. Left ventricular thrombus was identified in only five patients (positive identification in four, and equivocal in one), all in the streptokinase-treated group (p = NS). There were also no differences between streptokinase and control treatment in any of the echocardiographic variables in subgroups of patients with anterior infarction, inferior infarction, no prior infarction or reperfusion with streptokinase. It is concluded that intracoronary streptokinase given relatively late in the course of acute myocardial infarction does not result in improved global or regional wall motion or a reduction in left ventricular thrombus or aneurysm formation in survivors studied 2 months after myocardial infarction.

Aged↗
PubMed1985

Survival following coronary artery bypass grafting in patients with severe angina pectoris (CASS). An observational study.

This observational study evaluates the effects of the severity of angina pectoris and the treatment method upon the survival of 4,209 patients in the Coronary Artery Surgery Study registry. In this nonrandomized study, these patients met the criteria used in the Coronary Artery Surgery Study randomized trial, except for the degree of angina pectoris and the method of selection of treatment. The 5 year survival rate was greater than or equal to 93% in patients with Class I and II angina pectoris and normal left ventricular function, regardless of the number of involved vessels or treatment received. Late survival of surgically treated patients with Class III and IV angina pectoris and normal left ventricular function was similar, regardless of the number of vessels involved (greater than or equal to 92% at 5 years). Nonoperatively treated patients with Class III and IV angina pectoris and normal left ventricular function had poorer 5 year survival rates, lowest (74%) in patients with three vessel disease (p less than 0.0001). This difference was also observed in patients with abnormal left ventricular function, three vessel disease, and Class III and IV angina pectoris; the 5 year survival rates were 82% for the operative group and 52% for the nonoperative group (p less than 0.0001). These data confirm the importance of clinical as well as anatomic factors in determining the prognosis of patients with ischemic heart disease and indicate that coronary artery bypass grafting can improve late survival in patients with triple vessel disease and severe angina pectoris.

Adult↗
PubMed1985

Design and study similarities and contrasts: the Veterans Administration, European, and CASS randomized trials of coronary artery bypass graft surgery.

There are three large randomized trials of early elective coronary artery bypass graft surgery vs early medical therapy in selected patients with stable angina pectoris: the Veterans Administration Study (or VA Study) with enrollment in 1972 to 1974, the European Coronary Surgery Study Group (or European Study) with enrollment in 1973 to 1976 and the Coronary Artery Surgery Study (CASS) with enrollment in 1975 to 1979. Design and other similarities and contrasts for the three trials are presented. For example if 50% luminal diameter narrowing is used to define a significantly diseased vessel and patients with left main coronary artery disease are eliminated from the VA and European studies, the percentages of patients with one-, two-, and three-vessel disease are: VA 16%, 34%, and 50%; European 0%, 43%, and 57%; CASS 19%, 31%, and 51%. The VA and European studies enrolled patients with NYHA anginal classes I through IV, whereas CASS enrolled patients with Canadian Heart Association classes I and II, as well as patients asymptomatic for chest pain after a myocardial infarction. Other study features of note include the differing geographic locations and time of enrollment. In the VA Study, surgery was performed within 2 months on 94% of those randomly assigned to surgery; the mean time to surgery (of those not crossing over to medicine) in CASS was 54 days; and the European Study had a mean delay of 3.9 months. The characteristics of the clinics, socioeconomic environments, and medical care and referral systems may be important to interpreting results, although they were not clearly specified.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

The effect of clinical characteristics on the comparison of medical and surgical therapy in the Coronary Artery Surgery Study (CASS) and the Veterans Administration Cooperative trial.

The CASS randomized trial was compared with the Veterans Administration (VA) randomized study of coronary bypass surgery with respect to the influence of clinical characteristics on the comparison of medical and surgical therapy. With regard to clinical baseline characteristics, the CASS population was overall at lower risk than the VA population. Average percent survival for years 1 through 6 were greater in the CASS than in the VA study for patients in both the medical and surgical groups. In the VA population, a multivariate risk index was developed with the use of presence or absence of New York Heart Association functional class III or IV, history of hypertension, history of myocardial infarction, and ST depression on the resting electrocardiogram. Low-, middle-, and high-risk terciles in the VA study population were determined based on this index. In the low-risk tercile, VA patients treated medically had a greater percent survival at 6 years than those treated surgically. In the high-risk tercile, VA patients treated surgically had markedly improved survival compared with those treated medically. These results were not replicated by the CASS study. In CASS, there were no significant differences between patients assigned to medical and surgical treatment within the terciles. Other noninvasive risk indexes were explored in CASS, but no subgroups defined solely by clinical features could be found wherein patients assigned to medical and surgical therapy were significantly different. Basic differences in the populations sampled are the most probable reason for the different results in the CASS and VA trials.

Clinical Trials as Topic↗
PubMed1985

Exercise testing in the Coronary Artery Surgery Study randomized population.

Exercise electrocardiographic stress testing was performed in 81% of the 780 patients randomized in the Coronary Artery Surgery Study at entry. The cumulative survival at the end of 7 year follow-up was 90% for those assigned to surgical treatment and 88% for those assigned to medical therapy (p = NS). These survival rates did not differ significantly from either those of the entire randomized cohort or those of the 149 patients who did not have a qualifying exercise test at baseline. No differences in important baseline characteristics existed between those who were exercised and not exercised at entry. Stratification of patients according to the degree of ST segment depression (less than 1 mm, greater than or equal to 1 mm, greater than 2 mm) and final exercise stage achieved during a Bruce protocol treadmill test (final stage less than or equal to 1, stage 2 and greater than or equal to stage 3) failed to show any significant differences in 7 year survival rates between medically and surgically assigned patients. Additionally no differences in survival were noted within either the medical or surgical groups regardless of the degree of ST segment depression or the final stage achieved. The presence of exercise-induced angina, however, identified patients who had a survival advantage if assigned to surgical therapy, with a 7 year survival rate of 94% compared with 87% for medically assigned patients (p = .007).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Global and regional left ventricular function and tomographic radionuclide perfusion: the Western Washington Intracoronary Streptokinase In Myocardial Infarction Trial.

The Western Washington Intracoronary Streptokinase In Myocardial Infarction Trial enrolled 250 patients with acute myocardial infarction. After the coronary angiographic diagnosis of thrombosis, patients were randomly assigned to receive either conventional therapy with heparin or intracoronary streptokinase followed by heparin. Of the 232 patients who survived at least 60 days, 207 (89%) underwent radionuclide ventriculographic determination of global and regional ejection fraction at a single institution at 62 +/- 35 days after infarction. In the first 100 patients, infarct size was also determined by quantitative single-photon emission tomographic imaging with thallium-201 (201Tl) and expressed as a percentage of the left ventricle with a perfusion defect. Overall, global ejection fraction did not differ between patients treated with streptokinase (45.9 +/- 13.9%; n = 115) and control patients (46.1 +/- 14.4%; n = 92, p = NS). Similarly, the regional posterolateral, inferior, and anteroseptal ejection fraction did not differ between the two groups. Infarct size as measured by 201Tl tomography was 19.4 +/- 12.8% (n = 52) of the left ventricle for the streptokinase group and 19.6 +/- 11.8% (n = 48; p = NS) for the control group. When patients were compared within groups by electrocardiographic location of infarction, time to treatment, or the presence or absence of vessel opening, there were no significant differences between streptokinase and control patients. Statistical inclusion of the 18 patients who died early and were unavailable for study also failed to modify the results, except for a possible reduction in inferior infarct size as measured by 201Tl tomography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Western Washington randomized trial of intracoronary streptokinase in acute myocardial infarction.

Two hundred fifty patients were enrolled in a multicenter, community-based study of the efficacy of intracoronary streptokinase thrombolysis in acute myocardial infarction; 134 were randomly assigned to streptokinase therapy and 116 were controls. All patients underwent left ventricular angiography and coronary arteriography before the random assignment. The mean time from the onset of symptoms to hospitalization was 134 +/- 144 minutes (S.D), and the mean time to random assignment was 276 +/- 185 minutes. Coronary reperfusion was achieved in 68 per cent of the streptokinase-treated group. The overall 30-day mortality was 18 (7.2 per cent); there were five deaths in the streptokinase-treated group (3.7 per cent) and 13 in the control group (11.2 per cent, P less than 0.02). Fifteen of the 18 deaths occurred in patients with anterior infarction. Intracoronary streptokinase therapy resulted in a nearly threefold reduction in the 30-day mortality after hospitalization for acute myocardial infarction.

Adult↗
PubMed1983

Prognostic value of angiographic indices of coronary artery disease from the Coronary Artery Surgery Study (CASS).

The Coronary Artery Surgery Study, CASS, enrolled 24,959 patients between August 1975 and June 1979 who were studied angiographically for suspected coronary artery disease. This paper compares the prognostic value for survival without early elective surgery of eight different indices of the extent of coronary artery disease: the number of diseased vessels, two indices using the number of proximal arterial segments diseased, two empirically generated indices from the CASS data, and the published indices of Friesinger, Gensini, and the National Heart and Chest Hospital, London. All had considerable prognostic information. Typically 80% of the prognostic information in one index was also contained in another. Our analysis shows that good prediction from angiographic data results from a combination of left ventricular function and arteriographic extent of disease. Prognosis may reasonably be obtained from three simple indices: the number of vessels diseased, the number of proximal arterial segments diseased, and a left ventricular wall motion score. These three indices account for an estimated 84% of the prognostic information available. 6-yr survival varies between 93 and 16% depending upon the values of these three indices.

Angiography↗
PubMed1982

Reproducibility of coronary arteriographic reading in the coronary artery surgery study (CASS).

Eight hundred seventy arteriograms from the Coronary Artery Surgery Study (CASS) were independently read by readers at two different clinics to evaluate the reproducibility of the interpretation of coronary arteriograms. Among proximal segments, the interpretation of lesions of the left main coronary artery were the least reproducible, P less than .02. When one angiographer reads a stenosis of 50% or more in the left main coronary artery, it is estimated that a second reader will report no lesion 18.6% of the time. In 94.7% of the films, the number of significantly (greater than or equal to 70% stenosis) diseased vessels was the same for both readers (72.1%) or differed by one vessel (22.6%). The reproducibility of interpretation of films of good or acceptable quality or completeness was better than the reproducibility of readings of arteriograms judged to be of poor quality or incomplete studies. The mean absolute difference between readings of the percent stenosis decreased over the time of the patient enrollment, 1975 to 1978. This may have resulted from major collaborative efforts made during the course of the study to improve the quality of angiography and to standardize the reading of the cine films.

Angiography↗
PubMed1982

Prognostic significance of angiographically documented left ventricular aneurysm from the Coronary Artery Surgery Study (CASS).

In order to evaluate the prognosis of medically treated patients with angiographically defined left ventricular aneurysm the data available from 1,136 patients with aneurysm (7.6 percent) from 15,019 patients with coronary artery disease in the Coronary Artery Surgery Study (CASS) registry were analyzed. Prior myocardial infarction, reduced ejection fraction, absence of angina and evidence of congestive heart failure were more commonly present in patients with aneurysm. The cumulative survival rates of medically treated patients at 1, 2, 3 and 4 years were 90, 84, 79 and 71 percent, respectively. The Cox analysis of survival indicated that the following variables predicted outcome: age, residual left ventricular function as assessed with angiography, left ventricular end-diastolic pressure, functional impairment due to congestive heart failure, number of vessels diseased, mitral regurgitation and S3 gallop. When survival was stratified for similar degrees of left ventricular dysfunction and functional impairment there was no difference between the survival of patients with aneurysm and that of registry patients without aneurysm. The data from this large population study indicate that the survival of patients with left ventricular aneurysm is better than previously recognized. The mortality in this group is primarily related to age, left ventricular function and clinical severity of heart failure. The presence of an aneurysm does not independently alter survival.

Coronary Angiography↗
PubMed1982

Survival of medically treated patients in the coronary artery surgery study (CASS) registry.

The objective of this study was to evaluate the impact on survival of the anatomic extent of obstructive coronary artery disease and of two measures of left ventricular (LV) performance. This study is based on 20,088 patients without previous coronary artery bypass graft surgery who were enrolled in the registry of the National Heart, Lung, and Blood Institute Coronary Artery Surgery Study from 1975 to 1979. The cumulative 4-year survival of medically managed patients was analyzed to determine the survival of specific subsets of patients with obstructive coronary disease. The vital status of 99.8% of the patients was known. The 4-year survival of medically treated patients with no significant obstructive disease was 97%, in contrast to 92%, 84% and 68% in patients with one-, two- and three-vessel disease, respectively. The presence of left main coronary artery disease decreased survival significantly. The 4-year survival decreased from 70% to 60% in patients with three-vessel disease when significant obstruction of the left main coronary artery was also present. Patients with significant coronary artery disease who had an ejection fraction of 50--100%, 35--49%, and 0--34% had a 4-year survival of 92%, 83% and 58%, respectively. The systolic contraction pattern was assessed in five selected segments and given a score of 1--6, with a score of 1 for normal function, increasing to 6 if an aneurysm was present. In a patient with normal LV contraction in all five segments of the LV ventricular angiogram, the LV score would equal 5. Patients with an LV score of 5--11, 12--16 and 17--30 had 4-year survivals of 90%, 71% and 53%, respectively. Patients with good LV function (a score of 5--11) had a 4-year survival of 94%, 91% and 79% for one-, two- and three-vessel disease, respectively. Patients with poor left ventricular function (score of 17--30) had a 4-year survival rate of 67%, 61% and 42% in one-, two- and three-vessel disease, respectively. Thus, LV function is a more important predictor of survival than the number of diseased vessels.

Coronary Artery Bypass↗
PubMed1982

Association of sex, physical size, and operative mortality after coronary artery bypass in the Coronary Artery Surgery Study (CASS).

The Collaborative Study in Coronary Artery Surgery (CASS) is a large multi-institutional study of the medical and surgical treatment of coronary artery disease. Fifteen cooperative institutions have carried out isolated coronary artery bypass grafting (CABG) on 6,258 men and 1,153 women during the period August, 1975, through May, 1980. The operative mortality in men was 1.9%, while the operative mortality for women undergoing CABG in the same institutions during the same time period was 4.5%. In an effort to explain this result, we used multivariate analysis to identify factors associated with increased mortality in women after CABG. The hypothesis that smaller physical size might be contributing to increased mortality was considered. Basic clinical and angiographic variables, size variables, including the average diameter of the grafted vessels, and gender were examined separately for patients who underwent elective and urgent and emergency procedures. Using multivariate information theory, we found that the most information regarding survival after operation is contained in basic clinical and angiographic variables. The physical size of the patient, including coronary artery diameter, helps predict operative mortality even after adjusting for differences in risk predicted by the basic variables and gender. However, the patient's sex is not statistically significantly related to the risk of surgical death given the information available from clinical and angiographic variables and from knowledge of patient size. One possible explanation of the excess risk for coronary artery operations in women is the smaller stature and the smaller diameter of the coronary arteries in this group of patients.

Adult↗