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Biomedical subjects

E R Bates

Publications and source records attributed to E R Bates.

At least 91 records · Page 5Linked to original sources
PubMed1989

Implications for patient triage from survival and left ventricular functional recovery analyses in 500 patients treated with coronary angioplasty for acute myocardial infarction.

The in-hospital course of 500 consecutive patients treated with coronary angioplasty for acute myocardial infarction was reviewed in relation to their clinical and angiographic presentation and angioplasty outcome to determine which patients benefit most from successful angioplasty in this setting. Patient age was 56 +/- 11 years (mean +/- SD) and 78% were men; 46% had anterior myocardial infarction, 49% received concomitant intravenous thrombolytic therapy, left ventricular ejection fraction was 47 +/- 11% and median time to angioplasty was 4.7 h (range 1 to 24). Angioplasty was successful in 78% of patients and partially successful in 7% of patients; the overall in-hospital mortality rate was 10.2%. Multivariate analysis found six independent correlates (p less than 0.05) of in-hospital mortality: left ventricular ejection fraction less than or equal to 30%, lack of postangioplasty infarct artery patency, age greater than 65 years, recurrent ischemia after successful angioplasty, emergency bypass surgery and arterial pressure on admission to the catheterization laboratory less than 100 mm Hg. After consideration of these predictors of survival in multivariate analyses, angioplasty success still was independently correlated with improved in-hospital survival for patients with cardiogenic shock (p = 0.002) and anterior myocardial infarction (p = 0.007). A trend toward an independent beneficial effect of successful angioplasty on survival was also noted in patients with inferior wall infarction and precordial ST segment depression (p = 0.063) and for all patients who were hypotensive on admission to the catheterization laboratory, regardless of the infarct site (p = 0.057).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1989

Combined tissue-type plasminogen activator and prostacyclin therapy for acute myocardial infarction. Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) 4 Study Group.

Current limitations of recombinant tissue-type plasminogen activator (rt-PA) therapy for acute myocardial infarction include failure to achieve recanalization in 25% of patients, reocclusion and reperfusion injury. Iloprost, a stable analogue of prostacyclin (PGI2), has been demonstrated to facilitate thrombolysis and reduce myocardial stunning in experimental models. To evaluate combined therapy, rt-PA (100 mg 3 h) and Iloprost (2 ng/kg per min for 48 h) were administered to 25 patients and then rt-PA alone (same dose) was given to an additional 25 patients with evolving myocardial infarction. At 90 min after drug administration, infarct-related vessel patency was observed in 11 (44%) of 25 who received rt-PA plus Iloprost compared with 15 (60%) of 25 who received rt-PA alone (p = 0.26). At 1 week, reocclusion had occurred in 3 (14%) of 21 patients who received combined therapy compared with 6 (26%) of 23 patients treated with rt-PA alone (p = 0.46). Ejection fraction increased significantly from baseline to 7 days for rt-PA alone whereas it decreased with combined therapy (rt-PA alone whereas it decreased with combined therapy (rt-PA alone: 47.3 +/- 11.5% at baseline to 50.4 +/- 9.8% at 7 days; rt-PA plus Iloprost: 51.3 +/- 10.1% at baseline to 49.0 +/- 9.4% at 7 days; difference between groups p = 0.05). At 4 h after therapy, fibrinogen decreased 33% for rt-PA plus Iloprost compared with a 52% for rt-PA alone (p = 0.001). Fibrinogen degradation products increased 60% more for rt-PA alone than for rt-PA plus Ilprost. Thus, the combination of rt-PA plus Iloprost at the doses employed did not improve immediate or follow-up coronary artery patency or left ventricular functional recovery compared with that achieved with rt-PA alone.

Cardiovascular Agents↗
PubMed1989

Thrombolysis and Angioplasty in Myocardial Infarction (TAMI-1) trial: influence of infarct location on arterial patency, left ventricular function and mortality.

The influence of infarct location on arterial patency, left ventricular function and mortality after 150 mg of intravenous recombinant tissue-type plasminogen activator (rt-PA) and selective coronary angioplasty was studied in 386 patients with acute myocardial infarction. In 329 patients with acute and 1 week angiograms, the 90 min infarct-related artery patency rate after rt-PA in the left anterior descending, the left circumflex and the right coronary artery was 77, 68 and 68%, respectively. Angioplasty, performed in half the patients, resulted in a final acute patency rate of 93%, which was not related to arterial distribution. Repeat catheterization and revascularization were required in 12% of patients before day 7 and were independent of arterial distribution. The reocclusion rate for the right coronary artery (21%) was higher than that for the left anterior descending (12%) or left circumflex (5%) artery (p = 0.01). Acute and 1 week contrast ventriculograms suitable for analysis were available in 266 patients. Whereas serial left ventricular ejection fraction did not improve during the course of this study, serial regional wall motion (centerline chord method) improved in each arterial distribution. The in-hospital mortality rate of 6% was not related to arterial distribution, although death was twice as likely with proximal compared with distal lesions. Ten of 11 patients who died in the group with the left anterior descending artery as the infarct-related artery had a lesion proximal to the first septal perforator branch.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Sustained saline-induced secretion of atrial natriuretic hormone is not maintained by atrial stretch.

To determine the relationship between changes in right and left atrial pressures and changes in plasma levels of immunoreactive atrial natriuretic hormone (ANH), 11 normal men were studied during rapid infusion of 1 L 150 mmol/L NaCl. Right atrial pressure, pulmonary capillary wedge pressure, and peripheral plasma ANH levels were measured serially for 30 min in 6 men and for 90 min in 5 men. There were significant increases in right atrial pressure at 15 and 30 min [4.8 +/- 0.4 (+/- SE) vs. 8.9 +/- 0.3 and 6.5 +/- 0.4 mm Hg; P less than 0.001] and in pulmonary capillary wedge pressure at the same time intervals [8.5 +/- 0.6 vs. 13.6 +/- 0.8 (P less than 0.001) and 10.6 +/- 0.6 mm Hg (P less than 0.01)]. Plasma ANH increased significantly at 30 min (11.5 +/- 2.4 vs. 20.6 +/- 3.0 pmol/L; P less than 0.001). Regression analysis revealed no correlation between the increase in plasma ANH at 30 min and the increase in either right atrial or pulmonary capillary wedge pressure at 15 min (r = 0.46; P = 0.16 for right atrial pressure; r = 0.02; P = 0.96 for pulmonary capillary wedge pressure). In the 5 men studied for 90 min, right atrial and pulmonary capillary wedge pressures returned to basal values by 45 min. In contrast, plasma ANH levels remained significantly elevated at all sampling times from 30-90 min (P less than 0.001); the peak value occurred at 75 min. We conclude that ANH secretion persists after saline infusion and that the cause of this prolonged secretion is not atrial stretch.

Adult↗
PubMed1989

Thrombolytic therapy for acute myocardial infarction.

Thrombolytic therapy in AMI restores infarct artery patency, preserves LV function, and decreases hospital mortality. Although hemorrhagic complications including stroke can occur, the incidence of stroke is not increased compared with control groups. Aspirin must be administered as soon as possible to inhibit platelet function, and an adjunctive role for early beta-blocker therapy may be important. Acute cardiac catheterization and coronary angioplasty need not be routinely performed in stable patients after tPA therapy, but should be considered in unstable patients. Two trials suggest that aggressive use of coronary angioplasty or bypass graft surgery before hospital discharge to preserve infarct artery patency and to prevent postinfarction ischemia is associated with an important improvement in long-term prognosis. Thrombolytic therapy should be considered standard care for patients whose ischemic chest pain lasts 20 min to at least 6 h in duration and who have an injury current on their ECG unless they are at increased risk for bleeding. The need for and timing of cardiac catheterization, coronary angioplasty, and surgical revascularization after AMI requires further evaluation.

Angioplasty, Balloon↗
PubMed1989

Early hospital discharge in the myocardial reperfusion era.

The prognosis of patients with acute myocardial infarction has improved dramatically over the past several decades. New treatment strategies, however, have incrementally increased the expense of treating these patients. Early hospital discharge is one potential way of offsetting some of this expense. Cardiac catheterization can greatly facilitate patient selection for early discharge by defining patients with low-risk anatomy who do not require additional diagnostic testing or therapy, by documenting infarct artery patency, an important predictor of a favorable prognosis, and by diagnosing patients who can expeditiously be revascularized by coronary angioplasty.

Cardiac Catheterization↗
PubMed1988

Infarct vessel status after intravenous tissue plasminogen activator and acute coronary angioplasty: prediction of clinical outcome.

To determine the risk of arterial reocclusion or recurrent ischemia after acute intervention in myocardial infarction, we analyzed the results of coronary arteriography performed acutely and at 1 week in 50 consecutive patients who received acute intervention. Successful recanalization of the infarct vessel was achieved in 46 (92%) patients after therapy with intravenous tissue plasminogen activator, percutaneous coronary angioplasty, or both. Follow-up angiography in 44 showed early reocclusion in 10 patients (23%). Intermittent patency during acute arteriography was always associated with reocclusion; suboptimal (Thrombolysis in Myocardial Infarction [TIMI] class 2) flow was associated with a 50% rate of reocclusion. Although residual stenosis of greater than 50% alone was not predictive of rethrombosis, 90% of all reocclusions were associated with either stenosis greater than 50%, TIMI 2 flow, or intermittent patency. Absence of these angiographic risk factors predicted a 95% patency rate at follow-up. In-hospital cardiac complications occurred in 17 of 23 (74%) patients with residual stenosis of greater than 50% (death in four, ischemia in 13), and late revascularization was required in 53% of survivors. Only 15% of the group with less than 50% stenosis had an in-hospital ischemic event (p less than 0.001). Thus, after acute intervention, an infarct vessel with intermittent patency or suboptimal flow is associated with a high rate of reocclusion. Residual stenosis greater than or equal to 50% appears to predict a high incidence of negative in-hospital clinical outcomes and the need for subsequent revascularization.

Adult↗
PubMed1988

Quantitative regional curvature analysis: a prospective evaluation of ventricular shape and wall motion measurements.

To overcome the assumptions and approximations mandated by the use of traditional wall motion methodologies, a method was recently developed for measuring ventricular shape based on quantitative curvature analysis of ventricular outlines. This study was designed to assess prospectively the performance of this algorithm, to compare it to traditional wall motion measurements (centerline method), and to determine the comparative degree to which each method mimicked the interpretation of wall motion by clinical observers. Semiquantitative visual grading of regional function in 52 patients was performed by four independent observers on two occasions. Anterior, apical, or inferior segments were judged to be normal (0 points) or abnormal (1 point) based on viewing nonrealigned, end-diastolic and end-systolic ventricular silhouettes from cineventriculograms obtained in the 30-degree right anterior oblique projection. Each segment was assigned a collated score ranging from 0 (all observers felt the region was normal on both readings) to 8 (all observers felt the region was abnormal on both readings). Quantitative regional curvature analysis and wall motion analysis (centerline method) were performed. Quantitative shape and wall motion scores correlated equally well with the semiquantitative visual scores. When a visual score of greater than or equal to 4 was used to designate an abnormal segment, both quantitative approaches demonstrated comparable sensitivity, specificity, and concordance rates. Both methods achieved optimal performance when maximum and minimum deviations from normal were recorded. Under these circumstances, the shape analysis demonstrated a greater concordance with the clinical diagnosis than did wall motion analysis (99% vs-93%, p less than 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1988

Reperfusion therapy in inferior myocardial infarction.

This review summarizes the multicenter trial results of reperfusion therapy for treatment of inferior myocardial infarction. Therapy with intracoronary streptokinase or intravenous recombinant tissue plasminogen activator (rt-PA) produced higher patency rates than did intravenous streptokinase. Reocclusion was more common when the right coronary artery was the infarct-related artery, irrespective of treatment strategy. Left ventricular ejection fraction was improved compared with that in control patients, especially when the time from symptom onset was brief or when patency rates were high. Enzymatic infarct size was reduced in treated patients. A trend toward mortality reduction in treated patients was found in four studies and was statistically significant in the Second International Study of Infarct Survival (ISIS-2) trial. Precordial ST segment depression in inferior myocardial infarction is associated with values for enzyme release, left ventricular ejection fraction and mortality similar to those in anterior infarction. Patients with inferior infarction who present within 6 h of symptom onset with precordial ST segment depression should be considered candidates for intravenous thrombolytic therapy with rt-PA; immediate cardiac catheterization and possible coronary angioplasty should be limited to those who are in hemodynamically unstable condition. Patients without precordial ST segment depression who present within 3 h of symptom onset and who do not have risk factors for bleeding should also be candidates for intravenous rt-PA therapy. The prognosis of other patients with inferior myocardial infarction is so good that the issue of thrombolytic therapy remains unsettled.

Clinical Trials as Topic↗
PubMed1988

Predictors of success for coronary angioplasty performed for acute myocardial infarction.

To evaluate the predictors and likelihood of success for coronary angioplasty performed in the setting of acute myocardial infarction, 300 consecutive patients with 321 coronary stenoses were studied retrospectively. Success was defined as final diameter stenosis less than 70% and Thrombolysis in Myocardial Infarction (TIMI) flow grade greater than or equal to 2. Nine clinical variables and 15 angiographic variables were assessed. Seventy-nine percent of patients were men; the mean age was 56 +/- 11 years, and 54% of patients also received thrombolytic therapy. The mean left ventricular ejection fraction was 46 +/- 11%, and 18 patients (6%) were in cardiogenic shock. Angioplasty success in the infarct-related artery was achieved in 240 patients (80%). In 177 total occlusions (TIMI flow grade less than or equal to 1), the success rate was 75.7% and success was independently predicted by 1) an ejection fraction greater than 30% (p = 0.001); 2) no arterial bend greater than or equal to 45 degrees at the site of angioplasty (p = 0.008); and 3) no triple vessel disease (p = 0.014). In 144 subtotal occlusions (TIMI flow grade greater than or equal to 2), procedural success was achieved in 84.7% and was predicted by 1) absence of thrombus greater than 5 mm (p = 0.023), and 2) absence of other stenoses greater than or equal to 50% in the same artery (p = 0.043), whereas patency without further emergency intervention was achieved in 71.7% and was predicted only by patient age less than or equal to 60 years and absence of cardiogenic shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

A comparison of 35 mm cine film and digital radiographic image recording: implications for quantitative coronary arteriography. Film vs. digital coronary quantification.

To assess potential differences in the intrinsic properties of image recording media and their impact on quantitative coronary arteriography, we used an automatic quantitative arteriography computer program to analyze cine film and digital radiographic images of a radiographic arterial phantom. The phantom consisted of a lucite plate with precision-drilled lumena ranging from 0.5 to 5.0 mm in diameter. Film images were digitized at 2048 X 2048 pixel resolution, and digital radiographic images were acquired at 512 X 512 and 1024 X 1024 resolution. Arterial geometric diameter, percent diameter stenosis, densitometric relative cross-sectional area, and densitometric percent area stenosis were measured. All three techniques were equivalent in measuring diameters with a high degree of overall accuracy (R greater than .992). All methods overestimated diameters below 1.0 mm. Both 512 X 512 and 1024 X 1024 digital images were superior to film for densitometric measurement of relative area (R = .995 vs. R = .940, P = .0032). We conclude that automated analysis of digital radiographic images yields results that are similar in geometric precision but greater in densitometric precision than film analysis.

Cineradiography↗
PubMed1988

Percutaneous transluminal coronary angioplasty improves survival in acute myocardial infarction complicated by cardiogenic shock.

Modest survival benefits have been reported in patients with acute myocardial infarction complicated by cardiogenic shock who were treated with early surgical revascularization or thrombolytic therapy. To determine whether coronary angioplasty improves survival, 87 patients with cardiogenic shock complicating acute myocardial infarction at the University of Michigan, Ann Arbor, Michigan, from 1975 to 1985 were retrospectively analyzed. Patients in group 1 (n = 59) were treated with conventional therapy; patients in group 2 (n = 24) were treated with conventional therapy and angioplasty. Extent of coronary artery disease, infarct location, and incidence of multivessel disease were similar between groups. Hemodynamic variables including cardiac index, mean arterial pressure, and pulmonary capillary wedge pressure were also similar. The 30-day survival was significantly improved for group 2 patients (50% vs. 17%, p = 0.006). Survival in group 2 patients with successful angioplasty was 77% (10 of 13 patients) versus 18% (two of 11 patients) in patients with unsuccessful angioplasty, (p = 0.006). The findings suggest that angioplasty improves survival in cardiogenic shock compared with conventional therapy with survival contingent upon successful reperfusion of the infarct-related artery.

Angioplasty, Balloon↗
PubMed1988

Effect of vasopressors on atrial natriuretic factor and hemodynamic function in humans.

To assess the effects of vasopressors on plasma levels of immunoreactive atrial natriuretic factor (ANF), 13 normal men were studied on two occasions. On the experimental day, subjects received sequential 15-minute intravenous infusions of angiotensin II in doses of 4, 8, and 16 pmol/kg/min. Following a 30-minute recovery period, subjects received sequential 15-minute infusions of phenylephrine in doses of 0.4 and 0.8 micrograms/kg/min. Right atrial pressure, mean pulmonary capillary wedge pressure, pulmonary artery pressure, mean systemic arterial pressure, and plasma levels of renin activity, aldosterone, angiotensin II, and immunoreactive ANF were obtained sequentially throughout the protocol. During the control day, vehicle was infused and plasma samples were obtained for hormone measurements. Infusion of angiotensin II and phenylephrine increased mean systemic arterial pressure in a stepwise fashion. Both right atrial pressure and pulmonary capillary wedge pressure increased significantly during both doses of phenylephrine, but only the highest dose of angiotensin II significantly increased atrial pressures. Plasma levels of immunoreactive ANF increased parallel with the changes in right atrial pressure and pulmonary capillary wedge pressure, with significant increases occurring only at the highest dose of both pressors. Angiotensin II and aldosterone levels increased and renin activity decreased during infusion of angiotensin II. There were no significant changes in plasma levels of immunoreactive ANF during the control day. These studies demonstrate that infusion of vasopressors increases plasma levels of ANF, but only when the vasopressor effect is associated with significant increases in right atrial and pulmonary capillary wedge pressures. Atrial stretch is the most likely mediator of the increase in plasma levels of immunoreactive ANF during vasoconstriction.

Adult↗
PubMed1988

Percutaneous atherectomy catheters.

Percutaneous atherectomy catheters have been developed as an alternative to balloon angioplasty for the treatment of atherosclerotic disease. This article summarizes the preliminary experimental and clinical results with these catheters.

Catheterization, Peripheral↗
PubMed1987

Early reperfusion therapy improves left ventricular function after acute inferior myocardial infarction associated with right coronary artery disease.

Quantitative global and regional ventriculographic analysis was performed acutely and 1 week later in 46 patients undergoing reperfusion procedures within 6 hours of acute inferior myocardial infarction due to right coronary artery disease. While serial improvement in global left ventricular ejection fraction was not demonstrated for the group, infarct zone regional wall motion did improve (-2.7 +/- 0.9 vs -2.3 +/- 1.4 SD/chord, p less than 0.007). Serial improvement in global ejection fraction was demonstrated in the subgroup of patients treated within 2 hours of symptom onset (55 +/- 10 vs 62 +/- 10%; n = 5; p less than 0.03). Infarct zone regional wall motion improved serially only in the subgroup of patients treated within 3 hours of symptom onset (-2.4 +/- 1.1 vs -1.3 +/- 1.7 SD/chord; n = 11; p less than 0.007). Patients with initially patent arteries had a higher ejection fraction on follow-up catheterization than did those with initially occluded vessels (61 +/- 11 vs 55 +/- 7%; p less than 0.02), and patients with patent arteries at follow-up had a higher ejection fraction than did those whose arteries were occluded (60 +/- 9 vs 48 +/- 4%; p less than 0.0001). We conclude that significant improvement in global and regional left ventricular function in patients with inferior myocardial infarction is possible when reperfusion therapy is begun early or when arterial patency is achieved.

Angioplasty, Balloon↗
PubMed1987

Community hospital administration of intravenous tissue plasminogen activator in acute myocardial infarction: improved timing, thrombolytic efficacy and ventricular function.

As an investigational fibrinolytic agent for acute myocardial infarction, intravenous recombinant tissue-type plasminogen activator (rt-PA) has been administered primarily in tertiary care and university centers. To determine the value of early initiation of such therapy, two satellite community hospital emergency rooms were established for use of rt-PA and the experience was compared among 142 consecutive patients who were transferred to a regional center for acute cardiac catheterization after intravenous rt-PA therapy. In Group I (n = 19), patients received rt-PA after interhospital transport to the regional center, but before cardiac catheterization. In Group II (n = 70), rt-PA therapy was initiated by the helicopter physician and nurse team after their arrival at the local community hospital emergency room. Group III patients (n = 53) had rt-PA administered in the local community hospital by the emergency room physician. Group III patients had earlier initiation of therapy (2.1 +/- 0.8 hours in Group III versus 3.8 +/- 1.2 hours in combined Groups I and II, p less than 0.001) and an increased rate of infarct vessel recanalization on the 90 minute coronary angiogram (81 in Group III versus 67% in combined Groups I and II, p = 0.057). The patients in Group III had a higher acute left ventricular ejection fraction (54 +/- 8% versus 50 +/- 9.5% in combined Groups I and II, p less than 0.01) and a trend toward an increased 7 day ejection fraction (55.5 +/- 9% versus 51.7 +/- 9.5%, respectively, p = 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1987

Value of exercise radionuclide ventriculography and thallium-201 scintigraphy in evaluating successful coronary angioplasty: comparison with coronary flow reserve, translesional gradient and percent diameter stenosis.

Assessment of percutaneous transluminal coronary angioplasty (PTCA) by early radionuclide exercise test was evaluated for 11 arteries undergoing a successful procedure. Exercise thallium-201 (Tl-201) and radionuclide ventriculography (RNV) were performed within 3 days before and after PTCA and compared to % diameter stenosis, % translesional gradient and regional coronary flow reserve (CFR) determined by digital coronary angiography. Primary success of the procedure was gauged by reduction in % stenosis from 80 +/- 12% to 31 +/- 12% (residual stenosis less than 50% in all cases) and reduction in % gradient less than 25% in all cases). Before PTCA, Tl-201 and/or RNV were abnormal in all cases. After PTCA, radionuclide exercise tests improved but remained abnormal in 4 instances. No relationship was found between residual % gradient or stenosis and pathological Tl-201 or RNV following PTCA, but abnormal tests were observed among 4 out of the 5 vessels with the lowest CFR (less than 1.69). In one case CFR remained depressed despite good angiographic, hemodynamic and scintigraphic results, this patient had unstable angina before the procedure. Among patients with stable symptoms, CFR of arterial distributions with positive Tl-201 or RNV after PTCA was significantly lower than that with negative tests (1.58 +/- 0.05 as compared to 1.90 +/- 0.25, P less than 0.02). Early radionuclide stress tests results thus reflect the physiologic improvement of coronary circulation. They may reflect the persistence of coronary flow abnormalities despite the relief of the epicardial stenosis.

Angioplasty, Balloon↗