Trends in coronary thrombolytic therapy for acute myocardial infarction (the Minnesota Heart Survey Registry, 1990 to 1993)

Multidecade-long trends (1986-2005) in the utilization of coronary reperfusion and revascularization treatment strategies in patients hospitalized with acute myocardial infarction: a community-wide perspective

OBJECTIVES

The objectives of our community-wide investigation were to describe multidecade-long trends (1986-2005) in the utilization of thrombolytic therapy, percutaneous coronary interventions, and coronary artery bypass graft surgery in patients hospitalized with acute myocardial infarction (AMI).

METHODS

The study sample consisted of 9422 greater Worcester (MA) residents hospitalized with confirmed AMI at all metropolitan Worcester medical centers in 11 annual periods between 1986 and 2005.

RESULTS

Increases in the utilization of percutaneous coronary interventions were observed between 1986 (2.0%) and 2005 (50.7%) with the most rapid increases beginning in the late 1990s. Utilization of coronary artery bypass graft surgery during hospitalization for AMI increased moderately in the 1990s, remained stable thereafter, and declined to being performed in 3.8% of hospitalized patients in 2005. The use of thrombolytic therapy increased between 1986 and 1995 (9.3-25.2%) and decreased markedly thereafter through 2005 (<1%). Demographic and clinical characteristics of several patients were associated with the receipt of these treatment regimens.

CONCLUSION

The results of this study in residents of a large Central New England community suggest an increasingly invasive approach to the management of patients hospitalized with AMI.

Protein carbonyl formation and tyrosine nitration as markers of oxidative damage during ischaemia-reperfusion injury to rat sciatic nerve

We have investigated the role of oxidative damage in peripheral nerve ischaemia-reperfusion injury using a rat sciatic nerve model. After 5 h ischaemia blood flow to the sciatic nerve was restarted and markers of oxidative damage measured after various times of reperfusion. As a marker of protein oxidative damage, protein carbonyl formation was measured using a sensitive enzyme-linked immunosorbent assay. Protein carbonyl content was unaffected by ischaemia alone, but increased by 55% after 12-18 h reperfusion, correlating with the onset of nerve pathology. Pretreatment with the xanthine oxidase inhibitor allopurinol prevented these abnormalities, suggesting that xanthine oxidase activity is proximal to oxidative damage during reperfusion injury. To determine whether formation of the potent oxidant peroxynitrite from nitric oxide and superoxide contributed to ischaemia-reperfusion injury, we measured the accumulation of 3-nitrotyrosine residues in proteins. Only one protein of 49,000 mol. wt contained significant amounts of 3-nitrotyrosine residues which was shown to be glial fibrillary acidic protein, an abundant cytoskeletal protein in Schwann cells. However glial fibrillary acidic protein contained 3-nitrotyrosine residues prior to ischaemia-reperfusion, and the amount of nitrated tyrosine residues in total glial fibrillary acidic protein did not increase significantly during reperfusion, therefore it was not possible to draw conclusions about the role of peroxynitrite in nerve reperfusion injury.

Elderly patients at highest risk with acute myocardial infarction are more frequently transferred from community hospitals to tertiary centers: reality or myth?

BACKGROUND

The objective of this study was to assess the characteristics of patients with acute myocardial infarction transferred from community hospitals. The study was designed as a retrospective chart review, and the data source was the Cooperative Cardiovascular Project from Michigan.

METHODS AND RESULTS

Included in the study were consecutive Medicare patients with acute myocardial infarction discharged from acute-care hospitals in Michigan between April 1, 1994, and July 31, 1995 (n = 7041): 2866 patients treated at community hospitals, 1241 transferred from community hospitals, 2731 admitted directly to tertiary hospitals, and 203 transferred from an outside emergency room to tertiary hospitals. The outcomes measured were patient characteristics, quality indicators, resource use, and 30-day mortality rates. Compared with patients not transferred, those transferred from community hospitals were younger, more frequently of the male sex, smokers, and were seen earlier after symptom onset. They had fewer cases of diabetes and lower Acute Physiology And Chronic Health Evaluation (APACHE II) scores and Medicare Mortality Prediction System (MMPS) values. Aspirin during hospitalization and at discharge, thrombolytic therapy, and reperfusion therapy were all used more frequently in transferred patients, whereas the other key discharge quality indicators were no different. Mortality rate at 30 days was lower for transferred patients (9.4% vs 25%, P <.0001) when compared with those not transferred.

CONCLUSIONS

Patients who are less ill, those who are seen early, and those who received thrombolytic therapy are more often transferred from community hospitals. On average, patients with greater comorbidity rates are treated at community hospitals and not transferred. Predicted and observed mortality rates were lower for the transferred group. Higher comorbidity rate in patients treated at community hospitals appears to be the major determinant of the observed higher mortality rates in these patients.

Hospital mortality of acute myocardial infarction in the thrombolytic era

OBJECTIVE

To examine the management and outcome of an unselected consecutive series of patients admitted with acute myocardial infarction to a tertiary referral centre.

DESIGN

A historical cohort study over a three year period (1992-94) of consecutive unselected admissions with acute myocardial infarction identified using the HIPE (hospital inpatient enquiry) database and validated according to MONICA criteria for definite or probable acute myocardial infarction.

SETTING

University teaching hospital and cardiac tertiary referral centre.

RESULTS

1059 patients were included. Mean age was 67 years; 60% were male and 40% female. Rates of coronary care unit (CCU) admission, thrombolysis, and predischarge angiography were 70%, 28%, and 32%, respectively. Overall in-hospital mortality was 18%. Independent predictors of hospital mortality by multivariate analysis were age, left ventricular failure, ventricular arrhythmias, cardiogenic shock, management outside CCU, and reinfarction. Hospital mortality in a small cohort from a non-tertiary referral centre was 14%, a difference largely explained by the lower mean age of these patients (64 years). Five year survival in the cohort was 50%. Only age and left ventricular failure were independent predictors of mortality at follow up.

CONCLUSIONS

In unselected consecutive patients the hospital mortality of acute myocardial infarction remains high (18%). Age and the occurrence of left ventricular failure are major determinants of short and long term mortality after acute myocardial infarction.

The "door-to-needle blitz" in acute myocardial infarction: the impact of a CQI project

BACKGROUND

A continuous quality improvement (CQI) project was conducted at Soroka Medical Center in Beer-Sheva, Israel, in an effort to identify and address causes of delays in thrombolytic therapy in patients arriving at a high-volume (160,000 patients per year) emergency department with acute myocardial infarction and thereby reduce the "door-to-needle time" (DTNT). The study had four phases: preintervention survey, peri-intervention process redesign, postintervention evaluation, and follow-up evaluation. CQI TEAM: The CQI team followed a seven-step protocol: problem definition, present-state screening, factors analysis, solution development, outcome evaluation, standardization, and conclusions.

RESULTS

A DTNT of 45 minutes was considered acceptable for this data set, and accordingly, patients were divided into an "early" group (n = 50, DTNT < 45 minutes), and a "late" group (n = 50, DTNT > or = 45 minutes). After the CQI intervention, the mean DTNT decreased from 61.8 +/- 32.5 (mean +/- standard deviation) to 47.6 +/- 18.5 minutes (p < 0.029). The prolonged DTNT time intervals of the late versus the early groups was primarily due to extended decision-making time (36.0 +/- 22.7 versus 13.6 +/- 6.7 minutes, p < 0.003), followed by time until therapy was initiated (26.2 +/- 14.2 versus 11.1 +/- 5.8 minutes, p < 0.002).

CONCLUSIONS

Results suggest that the 30-minute DTNT suggested by the American College of Cardiology/American Heart Association is appropriate for patients with a clear diagnosis and no contraindications for thrombolysis, but when the risk-benefit ratio of thrombolytic therapy raises concerns, a 45- to 60-minute DTNT may still be acceptable. Further CQI projects should address technical triage of simple cases and clinical estimation of risk-benefit ratio in complicated patients.

Overexpression of human copper, zinc-superoxide dismutase (SOD1) prevents postischemic injury

Superoxide and superoxide-derived oxidants have been hypothesized to be important mediators of postischemic injury. Whereas copper, zinc-superoxide dismutase, SOD1, efficiently dismutates superoxide, there has been controversy regarding whether increasing intracellular SOD1 expression would protect against or potentiate cellular injury. To determine whether increased SOD1 protects the heart from ischemia and reperfusion, studies were performed in a newly developed transgenic mouse model in which direct measurement of superoxide, contractile function, bioenergetics, and cell death could be performed. Transgenic mice with overexpression of human SOD1 were studied along with matched nontransgenic controls. Immunoblotting and immunohistology demonstrated that total SOD1 expression was increased 10-fold in hearts from transgenic mice compared with nontransgenic controls, with increased expression in both myocytes and endothelial cells. In nontransgenic hearts following 30 min of global ischemia a reperfusion-associated burst of superoxide generation was demonstrated by electron paramagnetic resonance spin trapping. However, in the transgenic hearts with overexpression of SOD1 the burst of superoxide generation was almost totally quenched, and this was accompanied by a 2-fold increase in the recovery of contractile function, a 2.2-fold decrease in infarct size, and a greatly improved recovery of high energy phosphates compared with that in nontransgenic controls. These results demonstrate that superoxide is an important mediator of postischemic injury and that increasing intracellular SOD1 dramatically protects the heart from this injury. Thus, increasing intracellular SOD1 expression may be a highly effective approach to decrease the cellular injury that occurs following reperfusion of ischemic tissues.

Gender differences in mortality after myocardial infarction. Why women fare worse than men

Several studies have indicated that women sustaining a myocardial infarction have a higher unadjusted short-term (i.e., in-hospital or 30-day) mortality than men. The advanced age of women at the time of presentation appears to be the major factor contributing to their worse prognosis relative to men. Controlling for age eliminates the association between female gender and increased mortality in most, but not all studies. This article reviews the data on age and other factors that might explain why women with a myocardial infarction fare worse then men.

Can we provide reperfusion therapy to all unselected patients admitted with acute myocardial infarction?

OBJECTIVES

This study sought to assess the maximal rate of acute Thrombolysis in Myocardial Infarction (TIMI) grade 3 patency that can be achieved in unselected patients.

BACKGROUND

Early and complete (TIMI grade 3 flow) reperfusion is an important therapeutic goal during acute myocardial infarction. However, thrombolysis, although widely used, is often contraindicated or ineffective. The selective use of primary and rescue percutaneous transluminal coronary angioplasty (PTCA) may increase the number of patients receiving reperfusion therapy.

METHODS

A cohort of 500 consecutive unselected patients with acute myocardial infarction were prospectively treated using a patency-oriented scheme: Thrombolysis-eligible patients received thrombolysis (n = 257) and underwent 90-min angiography to detect persistent occlusion for treatment with rescue PTCA. Emergency PTCA (n = 193) was attempted in patients with contraindications to thrombolysis, cardiogenic shock or uncertain diagnosis and in a subset of patients admitted under "ideal conditions." A small group of patients (n = 38) underwent acute angiography without PTCA. Conventional medical therapy was used in 12 patients with contraindications to both thrombolysis and PTCA.

RESULTS

Ninety-eight percent of patients received reperfusion therapy (thrombolysis, PTCA or acute angiography), and angiographically proven early TIMI grade 3 patency was achieved in 78%. Among patients with TIMI grade 3 patency, thrombolysis alone was the strategy used in 37%, emergency PTCA in 40% and rescue PTCA after failed thrombolysis in 15%; spontaneous patency occurred in 8%.

CONCLUSIONS

Reperfusion therapy can be provided to nearly every patient (98%) with acute myocardial infarction. Rescue and direct PTCA provided effective early reperfusion to patients in whom thrombolysis failed or was excluded.