Impact of a region-wide approach to improving systems for heart attack care: the West Midlands thrombolysis project

Inconsistent measurement of acute coronary syndrome patients' pre-hospital delay in research: a review of the literature

BACKGROUND

Patients' treatment-seeking delay remains a significant barrier to timely initiation of reperfusion therapy. Measurement of treatment-seeking delay is central to the large body of research that has focused on pre-hospital delay (PHD), which is primarily patient-related. This research has aimed to quantify PHD and its effects on morbidity and mortality, identify contributing factors, and evaluate interventions to reduce such delay. A definite time of symptom onset in acute coronary syndrome (ACS) is essential for determining delay, but difficult to establish. This literature review aimed to explore the variety of operational definitions of both PHD and symptom onset in published research.

METHODS AND RESULTS

We reviewed the English-language literature from 1998-2013 for operational definitions of PHD and symptom onset. Of 626 papers of possible interest, 175 were deemed relevant. Ninety-seven percent reported a delay time and 84% provided an operational definition of PHD. Three definitions predominated: (a) symptom onset to decision to seek help (18%); (b) symptom onset to hospital arrival (67%), (c) total delay, incorporating two or more intervals (11%). Of those that measured delay, 8% provided a definition of which symptoms triggered the start of timing.

CONCLUSION

We found few and variable operational definitions of PHD, despite American College of Cardiology/American Heart Association recommendations to report specific intervals. Worryingly, definitions of symptom onset, the most elusive component of PHD to establish, are uncommon. We recommend that researchers (a) report two PHD delay intervals (onset to decision to seek care, and decision to seek care to hospital arrival), and (b) develop, validate and use a definition of symptom onset. This will increase clarity and confidence in the conclusions from, and comparisons within and between studies.

Meanaging Knowledge for the emergency care of heart attack patients: Paramedics and thrombolytic treatment

The objective of this paper is to examine the Knowledge Management(KM) paradigm in the context of UK paramedics' assessment and treatment of patients with suspected acute myocardial infarction (MI) or ;heart attack' We outline the role of thrombolytic therapy and other aspects of emergency cardiac care and discuss how contemporary KM tools and techniques can be used to support the development and retention of key clinical skills and knowledge in this emerging field of parcice.

Guideline implementation fails to improve thrombolytic administration

BACKGROUND

International randomised controlled trials conducted over the last two decades have consistently demonstrated improved mortality and morbidity resulting from thrombolytic therapy for patients with acute myocardial infarction (AMI). Subsequently, evidence-based guidelines have been designed and implemented to optimize thrombolytic delivery. The effect of evidence-based clinical guidelines on clinical practice is heavily influenced by strategies used to develop, disseminate and implement those guidelines.

AIMS

This study evaluated the impact of a collaborative, multifaceted implementation strategy for AMI management guidelines on thrombolytic usage in the Loddon Mallee Region, Victoria, Australia.

INTERVENTION

The multi-faceted implementation strategy included an inter-disciplinary team representing all treating venues contributing to the content of the "Guidelines for the Early Management of Acute Myocardial Infarction" followed by education sessions that coincided with the dissemination of the guidelines.

METHODS

A retrospective medical records audit 12 weeks before and 12 weeks after the intervention was used to evaluate the impact on proportion of those patients eligible and receiving a thrombolytic and door-to-needle time. Variables of treating venue, age, gender, type of AMI, and type of transport to hospital were also measured to determine their impact on results.

RESULTS AND CONCLUSIONS

A retrospective audit of 170 medical records found that the intervention appeared to have had no impact on the proportion of patients eligible and receiving a thrombolytic (74.2% vs. 62.5%: p=0.275), and door-to-needle time (67.7 min vs. 60.5 min: p=0.759). Venue specific influences produced a variety of patterns in thrombolytic delivery that require further exploration. This suggests that a single solution approach across multiple venues will have limited impact.

Using simulation to estimate the cost effectiveness of improving ambulance and thrombolysis response times after myocardial infarction

OBJECTIVES

To quantify the health gains and costs associated with improving ambulance and thrombolysis response times for acute myocardial infarction.

DESIGN

A computer simulation model. PATIENTS/SETTINGS: Patients experiencing acute myocardial infarction in England.

INTERVENTIONS

Improving the ambulance response time to 75% of calls reached within 8 minutes and the hospital arrival to thrombolysis time interval (door-to-needle time) to 75% receiving it within 30 minutes and 20 minutes, compared to best estimates of response times in the mid-1990s.

MAIN OUTCOME MEASURES

Deaths prevented, life years saved, and discounted cost per life year saved.

RESULTS

Improving the ambulance response to 75% of calls within 8 minutes resulted in an estimate of 5 deaths prevented or 57 life years saved per million population per year, with a discounted incremental cost per life year saved of 8540 pounds sterling over 20 years. The corresponding benefit of improving the door-to-needle time to 75% of myocardial infarction patients within 30 minutes was an estimated 2 deaths prevented and 15 life years saved per million population per year, with a discounted incremental cost per life year saved of between 10,150 pounds sterling to 54,230 pounds sterling over 20 years. Little further gain was associated with reaching the 20 minute target. Combining ambulance and thrombolysis targets resulted in 70 life years saved per million population per year.

CONCLUSIONS

Improving ambulance response times appears to be cost effective. Reducing door-to-needle time will have a smaller effect at an uncertain cost. Further benefits may be gained from reducing the time from onset of symptoms to starting thrombolysis.

Nine-year comparison of presentation and management of acute coronary syndromes in Ireland: a national cross-sectional survey

BACKGROUND

Shorter time to treatment is associated with lower mortality in acute coronary syndromes (ACS). A previous (1994) survey showed substantial delays for acute myocardial infarction (AMI) in Ireland. The present study compared current practice with 1994 and surveyed acute coronary syndromes as a more complete contemporary evaluation of critical cardiac care than assessing AMI alone.

METHODS

Following ethics committee approval, all centres (N = 39) admitting acute cardiac patients to intensive/coronary care unit provided information on 1365 episodes. A cross-sectional survey design was employed.

RESULTS

Since 1994, median hospital arrival to thrombolysis time was reduced by 41% (76 to 45 minutes). Thrombolysis was delivered more often in the emergency department in 2003 (48% vs 2%). Thrombolysis when delivered in the emergency department was achieved faster than thrombolysis delivered in intensive/coronary care (35 mins v 60 mins; z = 5.62, p < .0001). Suspected AMI patients who did not subsequently receive thrombolysis took longer to present to hospital (5 h vs 2 h 34 mins; z = 7.33, p < .0001) and had longer transfer times to the intensive/coronary care unit following arrival (2 h 17 mins vs 1 h 10 mins; z = 8.92, p < .0001). Fewer confirmed AMI cases received thrombolysis in 2003 (43% vs 58%). There was an increase in confirmed cases of AMI from 1994 (70% to 87%).

CONCLUSIONS

Substantial improvements in time to thrombolysis have occurred since 1994, probably relating to treatment provision in emergency departments. Patient delay pre-hospital is still the principal impediment to effective treatment of ACS. A recent change of definition of AMI may have precluded an exact comparison between 1994 and 2003 data.