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W D Weaver

Publications and source records attributed to W D Weaver.

At least 73 records · Page 4Linked to original sources
PubMed1997

Gender and acute myocardial infarction: is there a different response to thrombolysis?

OBJECTIVES: This study sought to 1) determine the effect of gender on early and late infarct-related artery patency and reocclusion after thrombolytic therapy for acute myocardial infarction; 2) examine the effect of gender on left ventricular function in response to injury/reperfusion; and 3) assess the independent contribution of gender to early (30-day) mortality after acute myocardial infarction. BACKGROUND: Women have a higher mortality rate than men after myocardial infarction. However, the effect of gender on infarct-related coronary artery patency and left ventricular response to injury/reperfusion have not been fully defined in the thrombolytic era. METHODS: Patency rates and global and regional left ventricular function were determined in patients at 90 min and 5 to 7 days after thrombolytic therapy for acute myocardial infarction. The effect of gender on infarct-related artery patency and left ventricular function was determined. Thirty-day mortality differences between women and men were compared. RESULTS: Women were significantly older and had more hypertension, diabetes, hypercholesterolemia, heart failure and shock. They were less likely to have had a previous myocardial infarction, history of smoking or previous bypass surgery. Ninety-minute patency rates (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3) in women and men were 39% and 38%, respectively (p = 0.5). Reocclusion rates were 8.7% in women versus 5.1% in men (p = 0.14). Women had more recurrent ischemia than men (21.4% vs. 17.0%, respectively, p = 0.01). Ninety-minute ejection fraction and regional ventricular function were clinically similar in women and men with TIMI 2 or 3 flow (ejection fraction [mean +/- SD]: 63.4 +/- 6% vs. 59.4 +/- 0.7%, p = 0.02; number of chords: 21.4 +/- 0.9 vs. 21.0 +/- 1.9, p = 0.7; SD/chord: -2.4 +/- 08 vs. -2.4 +/- 0.2, p = 0.9, respectively). No clinically significant differences in left ventricular function were noted at 5- to 7-day follow-up. Women had a greater hyperkinetic response than men in the noninfarct zone (SD/chord: 2.4 +/- 0.2 vs. 1.7 +/- 0.1, p = 0.005). The 30-day mortality rate was 13.1% in women versus 4.8% in men (p < or = 0.0001). After adjustment for other clinical and angiographic variables, gender remained an independent determinant of 30-day mortality. CONCLUSIONS: Women do not differ significantly from men with regard to either early infarct-related artery patency rates or reocclusion after thrombolytic therapy or ventricular functional response to injury/reperfusion. Gender was an independent determinant of 30-day mortality after acute myocardial infarction.

Aged↗
PubMed1997

Long-term follow-up of gender-specific outcomes after thrombolytic therapy for acute myocardial infarction from the GUSTO-I trial. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries.

Our objective was to assess gender differences in mortality 1 year after acute myocardial infarction (MI). The Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial database of 41,021 patients with suspected acute MI was used to generate 1-year Kaplan-Meier survival plots. Risk quartiles and mortality of women and men were compared. The unadjusted 1-year mortality rate for the initial GUSTO-I population and 30-day survivors demonstrates a large gender gap [odds ratio for all patients = 2.2, 95% confidence interval (CI), 2.0-2.3, p < 0.001]. For the initial population, when adjusted for age, the gender gap is still apparent (odds ratio = 1.4, 95%, CI = 1.3-1.5, p < 0.001) although no longer significant when adjusted using the 30-day survival model (odds ratio = 1.06, 95% CI = 0.97-1.15, p < 0.001). For the 30-day survivors, adjustment based on age alone explained the 1-year mortality difference (risk ratio = 0.96, 95% CI 0.85-1.07, p = 0.441). When the population was divided into expected risk quartiles, women were more likely to fall into the higher expected risk quartiles, even after adjusting for age. A gender gap after acute MI is apparent, nearly all of which occurs within the first 30 days. A substantial portion of the gender gap is explained by the increased age of women, and the rest of the gap may be attributed to differences in variables predictive of 30-day mortality. During 1-year follow-up, the late mortality of women is no greater than that of age-matched men.

Female↗
PubMed1997

Clinical trial results with a new plasminogen activator.

Thrombolysis has become an accepted form of therapy for acute myocardial infarction. As demonstrated in the Global Utilization of Streptokinase and t-PA for Occluded Arteries trial, early, complete and sustained patency of the infarct-related coronary artery is correlated with reduced mortality. However, current thrombolytic regimens are able to achieve such patency within 90 min in only 81% of cases. To improve the risk/benefit ratio of thrombolytic therapy, newer agents such as reteplase have been developed to establish more rapid, more complete and more stable coronary artery patency, thus reducing mortality. This report summarizes the pharmacological properties of reteplase. It also summarizes the findings from various animal and clinical studies in which reteplase was compared with alteplase and streptokinase and the findings from animal and clinical studies evaluating infusion, single-bolus, double-bolus, doses of reteplase.

Amino Acid Sequence↗
PubMed1996

Characteristics, management, and outcome of patients with acute myocardial infarction treated with bypass surgery. Myocardial Infarction Triage and Intervention Investigators.

BACKGROUND: Although multiple studies have addressed the efficacy of bypass surgery in patients with stable angina, there are relatively few studies that have evaluated the optimal timing, risk of hospital mortality, and long-term outcome for patients with bypass surgery performed in the setting of acute infarction. METHODS AND RESULTS: With data collected from all admitted patients with acute myocardial infarction to 19 Seattle-area hospitals between 1988 and 1994, we studied the characteristics, hospital course, and long-term outcome in 1299 patients who underwent bypass surgery. There was no difference in hospital mortality in patients operated on during the first 24 hours after admission compared with those operated on later in the hospital course (8.3% versus 7.2%; P=.60). Factors that predicted hospital mortality in those who underwent bypass surgery included increased age, prior bypass surgery, infarct extension, and stroke. Long-term outcome in those who underwent bypass surgery was excellent, with low rates of subsequent coronary angiography (7.4% at 3 years) and coronary angioplasty (2.6% at 3 years). Three-year survival was better in bypass recipients than in those treated medically (83% versus 66%; P < .0001), and this difference remained after multivariate adjustment for baseline differences (hazard ratio, 0.68; 95% CI, 0.55 to 0.85). CONCLUSIONS: Patients can be safely operated on early in the course of acute infarction, risk factors for hospital mortality are not substantially different from factors identified in the noninfarct setting, and bypass surgery in select patients after acute infarction is associated with low repeat procedure use and excellent long-term survival.

Adult↗
PubMed1996

A comparison of thrombolytic therapy with primary coronary angioplasty for acute myocardial infarction. Myocardial Infarction Triage and Intervention Investigators.

BACKGROUND: Several relatively small randomized trials have shown that primary angioplasty results in a better short-term outcome than thrombolytic therapy in patients with acute myocardial infarction. These results, however, have not been duplicated other than in investigational trials. METHODS: We compared mortality during hospitalization and long-term mortality, as well as the use of resources, among 1050 patients in a primary-angioplasty group and 2095 patients in a thrombolytic-therapy group. Patients were selected from the Myocardial Infarction Triage and Intervention Project Registry cohort of 12,331 consecutive patients admitted with acute myocardial infarction to 19 Seattle hospitals between 1988 and 1994. Because of the potential for selection bias, several subgroup analyses were performed that included patients eligible for thrombolysis, high-risk patients, and patients in the primary-angioplasty group who were treated at hospitals with high volumes of angioplasty. RESULTS: There was no significant difference in mortality during hospitalization or long-term follow-up between patients in the thrombolytic-therapy group and those in the primary-angioplasty group (mortality during hospitalization, 5.6 percent and 5.5 percent, respectively; P=0.93; adjusted hazard ratio for the risk of death within three years after primary angioplasty, 0.95; 95 percent confidence interval, 0.8 to 1.2). There was also no significant difference in mortality between high-risk subgroups of patients in the two treatment groups. The rates of procedures and costs were lower among patients in the thrombolytic-therapy group both at the time of hospital discharge and after three years of follow-up (30 percent fewer coronary angiograms, 15 percent fewer coronary angioplasties, and 13 percent lower costs after three years of follow-up). CONCLUSIONS: In a community setting, we observed no benefit in terms of either mortality or the use of resources with a strategy of primary angioplasty rather than thrombolytic therapy in a large cohort of patients with acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1996

Determinants of the use of coronary angiography and revascularization after thrombolysis for acute myocardial infarction.

BACKGROUND: Clinical trials and practice guidelines have identified clinical criteria for the use of coronary angiography and revascularization procedures after thrombolysis for acute myocardial infarction. The effect of these criteria on clinical practice has not been extensively evaluated. METHODS: We used classification-and-regression-tree (CART) and logistic-regression models to study the patients in the first Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries trial, to identify the variables that best predicted the use of angiography and revascularization procedures after thrombolysis. RESULTS: Among the 21,772 U.S. patients in the trial, 71 percent underwent coronary angiography before discharge from the hospital. Of these, 58 percent underwent revascularization (73 percent receiving angioplasty). The CART model for the use of angiography showed that age was the variable most predictive of angiography; only 53 percent of patients at least 73 years of age underwent angiography, as compared with 76 percent of those under 73. Among the older patients, age was again the most predictive factor; among the younger patients, the availability of angioplasty was a more important predictor (67 percent of patients in hospitals without angioplasty facilities underwent angiography, as compared with 83 percent in hospitals with such facilities). The next most important variable was recurrent ischemia, which was more predictive at hospitals without angioplasty facilities than at those with them. Both statistical models identified coronary anatomy as the most important predictor of the use and type of revascularization. CONCLUSIONS: More patients treated with thrombolysis underwent angiography and revascularization before discharge than might be expected. Younger age and the availability of the procedures appeared to be the major determinants of the use of coronary angiography, whereas coronary anatomy largely determined the use and type of revascularization. This process appeared to select low-risk patients for intervention rather than those at higher risk, who would be the most likely to benefit.

Age Factors↗
PubMed1996

Age and outcome with contemporary thrombolytic therapy. Results from the GUSTO-I trial. Global Utilization of Streptokinase and TPA for Occluded coronary arteries trial.

BACKGROUND: Elderly patients with acute myocardial infarction have much to gain from reperfusion with thrombolytic therapy but are also at increased risk of adverse events. We examined outcomes according to age of patients receiving thrombolysis in an international trial. METHODS AND RESULTS: Patients were randomized to streptokinase plus subcutaneous heparin, streptokinase plus intravenous heparin, accelerated tissue plasminogen activator (TPA) plus intravenous heparin, or streptokinase and TPA plus intravenous heparin. Clinical outcomes at 30 days (death, stroke, and nonfatal, disabling stroke) and 1-year mortality were summarized descriptively for patients aged < 65 (n = 24,708), 65 to 74 (n = 11,201), 75 to 85 (n = 4625), and > 85 years (n = 412) and assessed as continuous functions of age. Older patients had a higher-risk profile with regard to baseline clinical and angiographic characteristics. Mortality at 30 days increased markedly with age (3.0%, 9.5%, 19.6%, and 30.3% in the four groups, respectively), as did stroke, cardiogenic shock, bleeding, and reinfarction. Combined death or disabling stroke occurred less often with accelerated TPA in all but the oldest patients, who showed a weak trend toward a lower incidence with streptokinase plus subcutaneous heparin: odds ratio 1.13; 95% confidence interval 0.6, 2.1. Similarly, accelerated TPA treatment resulted in lower 1-year mortality in all but the oldest patients (47% TPA versus 40.3% streptokinase). CONCLUSIONS: Lower mortality and greater net clinical benefit were seen with accelerated TPA in patients aged < or = 85 years. Because data are limited for patients aged > 85 years, the relative superiority of a given thrombolytic regimen cannot be determined. The interactions of stroke and mortality with newer thrombolytic strategies must be examined explicitly in older patients.

Aged↗
PubMed1996

Influence of early prehospital thrombolysis on mortality and event-free survival (the Myocardial Infarction Triage and Intervention [MITI] Randomized Trial). MITI Project Investigators.

The Myocardial Infarction Triage and Intervention Trial of prehospital versus hospital administration of thrombolytic therapy markedly reduced hospital treatment times, but the 2 groups had similar outcomes. However, patients treated < 70 minutes from symptom onset had better short-term outcomes. The purpose of this study was to determine the long-term influence of very early thrombolytic treatment for acute myocardial infarction. A total of 360 patients were followed for vital status and cardiac-related hospital admissions over a period of 34 +/- 16 months. Patients enrolled in the trial had symptoms for < or = 6 hours, ST-segment elevation on the prehospital electrocardiogram, and no risk factors for serious bleeding. They received aspirin and recombinant tissue plasminogen activator either before or after hospital arrival. Primary end points in this study included long-term survival and survival free of death or readmission to the hospital for angina, myocardial infarction, congestive heart failure, or revascularization. Two-year survival was 89% for prehospital- and 91% for hospital-treated patients (p = 0.46). Event-free survival at 2 years was 56% and 64% for prehospital- and hospital-treated patients, respectively (p = 0.42). In patients treated < 70 minutes from symptom onset, 2-year survival was 98%, and it was 88% for those treated later (p = 0.12). Two-year event-free survival was 65% for patients treated early and 59% for patients treated later (p = 0.80). In this trial, poorer long-term survival was associated with advanced age, history of congestive heart failure, and coronary artery bypass surgery performed before the index hospitalization, but not with time to treatment.

Aged↗
PubMed1996

Randomized comparison of coronary thrombolysis achieved with double-bolus reteplase (recombinant plasminogen activator) and front-loaded, accelerated alteplase (recombinant tissue plasminogen activator) in patients with acute myocardial infarction. The RAPID II Investigators.

BACKGROUND: The therapeutic benefit of thrombolytic therapy has been shown to correlate directly with completeness (TIMI grade 3 flow) and speed of reperfusion of the infarct-related coronary artery. The purpose of the RAPID II study was to determine whether a double-bolus regimen of reteplase, a recently developed deletion mutant of wild-type tissue plasminogen activator, could improve 90-minute coronary artery patency rates achieved with the most successful standard regimen, an "accelerated" front-loaded infusion of alteplase. METHODS AND RESULTS: Three hundred twenty-four patients with acute myocardial infarction were randomized to receive (along with intravenous heparin and aspirin) either a 10 plus 10 megaunits double bolus of reteplase or front-loaded alteplase. The primary end point of "patency at 90 minutes, graded according to the TIMI classification" was centrally assessed in a blinded fashion. Infarctrelated coronary artery patency (TIMI grade 2 or 3) and complete patency (TIMI grade 3) at 90 minutes after the start of thrombolytic therapy were significantly higher in the reteplase-treated patients (TIMI grade 2 or 3: 83.4% versus 73.3% for front-loaded alteplase-treated patients, P = .03; TIMI grade 3: 59.9% versus 45.2%, P = .01). At 60 minutes, the incidence of both, patency and complete patency, was also significantly higher in reteplase-treated patients (reteplase versus alteplase, TIMI grade 2 or 3: 81.8% versus 66.1%, P = .01; TIMI grade 3: 51.2% versus 37.4%, P < .03). Reteplase-treated patients required fewer acute additional coronary interventions (13.6% versus 26.5%, P < .01), and 35-day mortality was 4.1% for reteplase and 8.4% for alteplase (P = NS). There were no significant differences between reteplase and alteplase in bleedings requiring a transfusion (12.4% versus 9.7%) or hemorrhagic stroke (1.2% versus 1.9%). CONCLUSIONS: Reteplase, when given as a double bolus of 10 plus 10 megaunits to patients with acute myocardial infarction, achieves significantly higher rates of early reperfusion of the infarct-related coronary artery and requires significantly fewer acute coronary interventions than front-loaded alteplase without an apparent increased risk of complications.

Adult↗
PubMed1996

Comparison of presentation, treatment, and outcome of acute myocardial infarction in men versus women (the Myocardial Infarction Triage and Intervention Registry)

This study compared the presentation (symptoms and signs), treatment, and outcome of 1,097 consecutive patients (851 men and 246 women) from the Myocardial Infarction Triage and Intervention (MITI) Project Registry with confirmed acute myocardial infarction (AMI), all of whom were initially evaluated in the prehospital setting, met clinical criteria for possible thrombolysis, and were followed throughout their hospital course. Women were older than men and had a higher prevalence of known cardiovascular risk factors, including systemic hypertension and congestive heart failure. The presentation of AMI with respect to symptoms, delay, and hemodynamic and electrocardiographic findings was for the most part indistinguishable between mean and women. Women appeared "undertreated" early in the course of AMI and were half as likely as men to undergo acute catheterization, angioplasty, thrombolysis, or coronary bypass surgery (odds ratio 0.5 [0.3 to 0.7]). The risk for hospital mortality in women was almost twice that for men (odds ratio 1.95 [1.01 to 3.8]). Hospital mortality after AMI was also independently predicted by older age, early evidence of hemodynamic instability, and an intraventricular conduction abnormality on the initial electrocardiogram. Although similar in its presentation, AMI in women is not as aggressively treated, and results in a less favorable outcome than in men. Gender as well as nongender-specific risk factors are important in assessing risk and the likelihood of early intervention after AMI.

Aged↗
PubMed1996

Comparisons of characteristics and outcomes among women and men with acute myocardial infarction treated with thrombolytic therapy. GUSTO-I investigators.

OBJECTIVE: To compare baseline characteristics, complications, and treatment-specific outcomes of women and men with acute myocardial infarction treated with thrombolytic therapy. DESIGN: Randomized controlled trial. PATIENTS AND SETTING: A total of 10315 women and 30706 men with acute myocardial infarction treated in 1081 hospitals in 15 countries as part of the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I). INTERVENTION: One of four thrombolytic regimens: (1) streptokinase with subcutaneous heparin; (2) streptokinase with intravenous heparin; (3) streptokinase plus alteplase (tissue-type plasminogen activator) with intravenous heparin; or (4) accelerated alteplase with intravenous heparin. MAIN OUTCOME MEASURES: Mortality, stroke, and nonfatal complications during 30-day follow-up. RESULTS: Women were on average 7 years older than men and delayed 18 minutes (median) longer after symptom onset before presenting to the hospital. After adjustment for age, women more often had a history of diabetes, hypertension, and smoking than men. Time to treatment was significantly longer in women (1.2 vs 1.0 hours; P<.001). Women had more nonfatal complications after treatment, including shock (9% vs 5%; P<.001), congestive heart failure (22% vs 14%; P<.001), serious bleeding (15% vs 7%; P<.001), and reinfarction (5.1% vs 3.6%; P<.001). Women had twice as many total strokes as men (2.1% vs 1.2%; P<.001), secondary to their older age at presentation. The unadjusted mortality rate was twice as high in women as men (11.3% vs 5.5%; P<.001); the relative risk (RR) of death was greater among women than men after adjustment for differences in baseline characteristics (RR=1.15; 95% confidence interval, 1.0 to 1.31). Although women and men underwent angiography at similar rates, there were small but significant differences in their rates of revascularization procedures (angioplasty: 35% of women and 32% of men; bypass surgery: 7% of women and 9% of men; P<.001 for both). The higher rate of stroke in women after treatment with alteplase (2.0% vs 1.9% with streptokinase and intravenous heparin) was offset by a greater relative reduction in mortality (10.3% vs 11.1%). CONCLUSION: Women who received thrombolytic therapy for treatment of acute myocardial infarction were at greater risk for both fatal and nonfatal complications than men.

Aged↗
PubMed1996

Randomized, double-blind, placebo-controlled dose-ranging study of tirofiban (MK-383) platelet IIb/IIIa blockade in high risk patients undergoing coronary angioplasty.

OBJECTIVES: The objectives of this double-blind, placebo-controlled, randomized dose-ranging study were 1) to examine the safety and tolerability of tirofiban (MK-383), a new nonpeptide platelet IIb/IIIa receptor antagonist, on a background of intravenous heparin and aspirin therapy; 2) to study the pharmacodynamics and pharmacokinetics of tirofiban; and 3) to evaluate the incidence of adverse cardiac outcomes (urgent repeat revascularization, myocardial infarction and death) with tirofiban versus placebo in a high risk subset of patients undergoing coronary angioplasty. BACKGROUND: Abrupt vessel closure complicates 4% to 8% of angioplasty procedures. Recent data have suggested that agents that antagonize the platelet glycoprotein IIb/IIIa receptor may reduce the incidence of adverse ischemic outcomes after coronary angioplasty. METHODS: Seventy-three patients received tirofiban in three sequential dose panels and 20 patients received placebo. Patients within each panel were randomized to receive either tirofiban or placebo in a 3:1 randomization design. Bolus doses of 5, 10 and 10 microg/kg and continuous infusion (16 to 24 h) doses of 0.05, 0.10 and 0.15 microg/kg per min were administered in panels I, II and III, respectively. Patients received concomitant heparin and aspirin for the angioplasty procedure. Data on patients receiving placebo (heparin and aspirin only) were pooled across panels for comparisons. The pharmacodynamic effect of tirofiban on ex vivo platelet aggregation to 5 micromol/liter adenosine diphosphate (ADP) and bleeding times were measured. Clinical outcomes were assessed in all patients, but the power to detect clinically meaningful differences (a one-third reduction in clinical events) between groups was limited (5%). RESULTS: Tirofiban was associated with a dose-dependent inhibition of ex vivo ADP-mediated platelet aggregation that was sustained during intravenous infusion and resolved rapidly after drug cessation. Adverse bleeding events, largely related to vascular access site hemorrhage, were slightly increased at the highest dose. Adverse clinical outcomes were infrequent in all patients and were not different among the small number of patients within each group. CONCLUSIONS: This study establishes a rational and generally well tolerated dosing regimen for administration of tirofiban as adjunctive therapy in high risk angioplasty patients. The impact of tirofiban on adverse clinical outcomes after angioplasty awaits definition by a larger clinical trial.

Angioplasty, Balloon, Coronary↗
PubMed1996

Early discharge in the thrombolytic era: an analysis of criteria for uncomplicated infarction from the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) trial.

OBJECTIVES: This study sought to readdress the definition of uncomplicated myocardial infarction and to apply clinical criteria for early discharge of such patients in the thrombolytic era. BACKGROUND: Previous studies proposed early hospital discharge at day 7 to 10 after acute myocardial infarction. The potential for earlier discharge of patients with uncomplicated infarction after thrombolysis remains undemonstrated. METHODS: We defined "uncomplicated infarction" a priori as the absence of death, reinfarction, ischemia, stroke, shock, heart failure (Killip class > 1), bypass surgery, balloon pumping, emergency catheterization or cardioversion or defibrillation in the first 4 hospital days. We applied this definition to 41,021 patients in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) trial. We examined death at 30 days and 1 year and rates of in-hospital reinfarction, heart failure, recurrent ischemia, shock and stroke in the uncomplicated and complicated groups created by application of our definition. We also assessed lengths of hospital and cardiac care unit stay. RESULTS: Application of our clinical criteria yielded 23,497 (57.3%) patients in the uncomplicated group at day 4 with a very low risk of death and in-hospital complications: 30-day mortality 1%, reinfarction 1.7%, heart failure 2.6%, recurrent ischemia 6.7%, shock 0.4% and stroke 0.2%. One-year mortality was 3.6%. The median hospital stay was 9 days (7, 12 [25th, 75th percentiles, respectively]), and the median cardiac care unit stay 3 days (3, 5). CONCLUSIONS: Simple clinical characteristics can identify a very low risk post-myocardial infarction population by hospital day 4. Use of these criteria for early discharge planning could substantially reduce length of stay for patients with uncomplicated acute myocardial infarction.

Aged↗
PubMed1996

Relation between symptom duration before thrombolytic therapy and final myocardial infarct size.

BACKGROUND: Myocardial salvage is most likely to occur when thrombolytic therapy is administered within 4 to 6 hours of the onset of symptoms of myocardial infarction. The impact of delays within this early time period on final myocardial infarct size are unknown. The purpose of this study was to quantitate the relation between final myocardial infarct size and duration of symptoms before initiation of thrombolytic therapy in patients treated within 6 hours of symptom onset. METHODS AND RESULTS: The findings from patients in four prospective randomized trials of thrombolytic therapy were combined for analysis. The study population consisted of 432 patients presenting within 6 hours of onset of symptoms of first acute myocardial infarction who met ECG criteria that allowed estimation of myocardial area at risk before treatment with thrombolytic therapy and who had thallium-201 myocardial infarct-size measurements performed several weeks after infarction. ECG analysis revealed no difference in myocardium at risk for infarction as a function of duration of symptoms before initiation of thrombolytic therapy. In contrast, univariate and multivariate analysis showed that final infarct size was highly dependent on duration of symptoms before initiation of therapy. Each 30-minute increase in symptom duration before thrombolytic therapy was associated with an increase in infarct size of 1% of the myocardium. Final infarct size in patients treated 4 to 6 hours after symptom onset was indistinguishable from patients who did not receive thrombolytic therapy. CONCLUSIONS: These findings suggest that for patients treated within 4 to 6 hours of the onset of symptoms, there is a progressive decline in the extent of myocardium salvaged as the duration of symptoms before therapy increases. These results support efforts to minimize the time delay between symptom onset and initiation of reperfusion therapy in all eligible patients.

Adult↗
PubMed1996

A comparison of the treatment of acute myocardial infarction between St. Petersburg, Russia and Seattle, Washington.

This study compared the baseline demographics, time to treatment and types of treatment of patients presenting with acute myocardial infarction in St. Petersburg, Russia and Seattle, WA. The study included 63 consecutive patients admitted to City Hospital #1 in St. Petersburg in July 1993. Comparative data for Seattle patients was obtained from the multi-year Myocardial Infarction Triage and Intervention project, a registry of all acute myocardial infarction patients hospitalized in the Seattle area. The results show a significantly prolonged time from symptom onset to presentation in Russia (51.8 h vs. 8.0 h; P < 0.001). Aspirin was used slightly more often in Seattle (78.9% vs. 74.6%; P = 0.40) while thrombolysis was used much more often in Seattle (22.5% vs. 6.3%; P = 0.002). There was also much less use of percutaneous transluminal coronary angioplasty (0% vs. 26.9%; P < 0.001), heparin (12.7% vs. 79.1%; P < 0.001), or cardiac catheterization (4.8% vs. 64.3%; P < 0.001). Also, the length of hospitalization was longer in St. Petersburg (23.8 +/- 10.8 vs. 7.5 +/- 5.1 days; P < 0.001). The findings in this study are an impetus for us all in understanding the magnitude of differences currently existing and the challenges for improving health care delivery in Russia.

Aged↗
PubMed1996

A composite view of cardiac rupture in the United States National Registry of Myocardial Infarction.

OBJECTIVES: This study was done to determine the incidence, timing and prevalence as a cause of death from cardiac rupture in patients with acute myocardial infarction. BACKGROUND: Several clinical trials and overview analyses have suggested that the survival benefit conferred by thrombolytic therapy may be offset by a paradoxic increase in early deaths from cardiac rupture. METHODS: Demographic, procedural and outcome data from patients with acute myocardial infarction were collected at 1,073 United States hospitals collaborating in the United States National Registry of Myocardial Infarction. RESULTS: Among the 350,755 patients enrolled, 122,243 received thrombolytic therapy. In-hospital mortality for the overall patient population, those not treated with thrombolytics (n = 228,512) and those given thrombolytics were 10.4%, 12.9% and 5.9%, respectively (p<0.001). Cardiogenic shock was the most common cause of death in each patient group. Although the incidence of cardiac rupture was low (<1.0%), it was responsible for 7.3%, 6.1% and 12.1%, respectively, of in-hospital deaths (p<0.001). Death from rupture occurred earlier in patients given thrombolytic therapy, with a clustering of events within 24 h of drug administration. Despite the early risk, death rates were comparatively low in thrombolytic-treated patients on each of the first 30 days. By multivariable analysis, thrombolytics, prior myocardial infarction, advancing age, female gender and intravenous beta-blocker use were independently associated with cardiac rupture. CONCLUSIONS: This large registry experience, including over 350,000 patients with myocardial infarction, suggests that thrombolytic therapy accelerates cardiac rupture, typically to within 24 to 48 h of treatment. The possibility that rupture represents an early hemorrhagic complication of thrombolytic therapy should be investigated.

Age Factors↗