Time is still muscle

By John Connole
Monday, 15 October, 2012

Time remains critical in the system of care for the treatment of acute myocardial infarction [heart attack], write Lorelle Martin, Carolyn Naismith, Associate Professor Omar Farouque and Simon Judkins.

‘Time is Muscle’ is the familiar 1980’s adage well known amongst health professionals managing acute coronary syndromes to infer that timely administration of thrombolysis for patients presenting with myocardial infarction results in less damage to the heart muscle.

In today’s health care setting, time remains a critical factor, but therapies have evolved to include primary percutaneous coronary intervention (PPCI) as first line treatment for ST elevation myocardial infarction (STEMI), and delay is strongly associated with increased mortality.1 The Australian guidelines outlined by the Cardiac Society of Australia and New Zealand (CSANZ), currently recommend that PPCI be delivered to a STEMI patient within 90 minutes of arrival to hospital.2 The measure of this time to treatment is commonly referred to as the Door to Balloon Time (DTBT).

The evidence base linking time delay with increased mortality for the STEMI patient is strong and essentially builds upon the evidence collected when thrombolysis was the gold standard treatment for myocardial infarction. PPCI is now considered to have an advantage over thrombolysis in terms of reduced mortality, provided it is delivered promptly.3 A study on a cohort of 27,000 patients, demonstrated that there was a 40 to 60% increase in ‘in-hospital’ mortality when DTBT was greater than 120 minutes.4 Similarly, it has been shown that ‘in-hospital’ mortality was 7.4% if DTBT was greater than 150 minutes, compared to 3.0% when DTBT was less than 90 minutes.5 More recently in a larger cohort of 43,000 patients, longer DTBTs (between 30-120 minutes) were associated with a higher adjusted risk of mortality and there was a reduced mortality of 1.3% when DTBT was under 30 minutes when compared to under 90 minutes.6

Clinical audit is a valuable tool that measures quality of care. In the healthcare setting it provides a local opportunity to compare current clinical practice to best practice guidelines and implement measurable change.7 Clinical audit also encourages accountability in standards of care, and demonstrates effectiveness of professional roles.8 The following article demonstrates how an ongoing clinical audit and system redesign dramatically reduced the DTBT for patients at a tertiary hospital in metropolitan Melbourne, to comply with the national guidelines for the management of STEMI patients.

Baseline clinical audit and design of process change

This particular clinical audit started as a collaborative project between the Cardiac Catheterisation Laboratory (CCL) and the Emergency Department (ED) at Austin Health. There was internal consensus, albeit anecdotally, that response times to the ST elevation myocardial infarction (STEMI) patient could be improved. A baseline audit was retrospectively carried out using the medical records of 82 consecutive STEMI patients who were admitted to the CCL via ED for PPCI. Nine months of data were collected, and revealed a median DTBT of 115 minutes for this group. These findings clearly indicated a need for improvement.

This revelation quickly led to the formation of a collaborative multidisciplinary working party utilising all key stakeholders: the Cardiac Catheter Laboratory, the Emergency Department and the Cardiology ward. It was decided that prospective data collection was required to capture real-time figures and help identify specific areas of delay. Concurrent data collection can provide immediate feedback on current performance, acting as a positive reinforcement to improve or maintain practice.9 A data collection tool was designed to capture specific timeframes within the pathway of care of the STEMI patient from ED to the Cath Lab. Primary PCI is treated as an emergency and can occur at any time of the day or night, therefore the data collection tool needed to be accessible and easy to use to ensure the recording of accurate and meaningful information. The following timeframes were collected and then calculated giving the final value of DTBT in minutes:

  • The time of arrival of the patient in emergency department (ED).

  • The time the first 12 lead electrocardiogram (ECG) was taken (to diagnose a STEMI).

  • The time first contact was made alerting the Cardiology registrar of the STEMI.

  • The time Cardiology responded to this call.

  • The time the Cath Lab team were activated (in and out of operating hours).

  • The time of arrival of the team (all members).

  • The time of arrival of the STEMI patient to Cath Lab from ED.

  • The time of the start of the emergency procedure (needle to skin time).

  • The time of first balloon inflation or use of aspiration catheter.

The Cardiac Catheter Laboratory (CCL) nursing staff were responsible for the DTBT data collection during or shortly after the emergency procedure and this information was verified by the project manager on a regular basis. In an effort to maintain validity of the data all ED ECG machines were regularly monitored for accuracy of time by ED educators, and the wall clocks in the CCL had weekly time checks against a website that gave the exact current time.

Patient information was de-identified using a chronological audit number, and the calculated DTBTs were entered onto a Microsoft Excel spreadsheet. Basic Excel functions were used to calculate data in terms of median times and total percentages.

Inclusion criteria were defined to provide delineation of the process map. Patients included were all STEMIs admitted to ED via ambulance or self-presentation. Patients excluded were all inter-hospital or interdepartmental transfers, non-ST elevation myocardial infarctions (NSTEMIs) or any patients that subsequently had normal coronary arteries at angiography. Needless to say, the same principle of rapid access to the Cath Lab still applied to all excluded patients.

This prospective data collection took place over a seven-month period with 74 consecutive STEMI patients. The median DTBT was calculated at 103 minutes for this prospective group, confirming the need for improvement strategies to be employed. The data collected was combined with the retrospective baseline audit data, providing a larger snapshot of the inefficiencies within the current process. The overall median DTBT was now 109 minutes (n=156) with 34% of these patients achieving DTBT under 90 minutes.

Concomitantly to this prospective data collection, regular meetings between all key stakeholders took place to design a process that provided rapid facilitation of cardiac services for the STEMI patient from ED admission through to the Cardiac Catheter Laboratory. The result of these meetings was a new process named the ‘Cath Lab Code’. This emergency code utilised hospital switchboard services to set off a paging tree to relevant members of the team, such as the Cardiology Registrar, NUM for the Cardiac Catheter Laboratory, Nurse in Charge for the Cardiology ward, Cardiac Liaison Nurse and the Bed Manager. The cardiology registrar was the only person required to respond to the page; for the rest of the paging tree it was an alert only. The paging message sent from ED gave a telephone extension for the Cardiology registrar to phone and briefly discuss the patient of concern. If the patient’s 12 lead ECG fitted the criteria for a STEMI, they were prepared for prompt transfer to the Cardiac Catheter Laboratory for immediate percutaneous intervention to the occluded coronary vessel (see diagram 1).

With the knowledge of the current inefficiencies and a new process to address these issues, the Cath Lab Code was drafted as a clinical policy and fully implemented into practice. During the final lead up to this implementation there was extensive communication, using hospital email distribution lists and organised educational sessions detailing the new process to the staff of ED, Cardiac Catheter Laboratory and the Cardiology ward.

Ongoing audit process

The Cath Lab Code was successfully implemented with an immediate improvement in the median DTBT. Audit data continued to be collected with the data collection tool adapted to capture the change to process with the inclusion of the ‘Cath Lab Code’ activation time. The continuation of data collection was deemed just as vital as the original audit data, as it provided the information required to reinforce and sustain the improvement in DTBTs.

In parallel with this audit process, there was consultation with Ambulance Victoria regarding a pre-hospital notification system for STEMI patients that was planned to be rolled out to hospitals across metropolitan Melbourne. It was based on the MonAmi trial,10 and involved the transmission of a pre-hospital 12 lead ECG by Ambulance Victoria on a STEMI patient in the field directly to the Emergency Department, enabling the Cath Lab services to be alerted prior to patient arrival and reducing time delays even further. This was a welcome system, and easily incorporated into the existing process of the Cath Lab Code. The pre hospital notification (PHN) system was successfully implemented 14 months after the original Cath Lab Code process change and continues to coexist as a process (see diagram 2.)


With two process changes occurring within a matter of 14 months, there were three separate timeframes to compare: Pre Cath Lab Code, Post Cath Lab Code, and Post Cath Lab Code + Pre Hospital Notification.

The following outlines the results in terms of DTBT and percentage of patients treated within the Cardiac Society of Australia and New Zealand (CSANZ) guidelines, for each separate timeframe and represents 43 months of data collection.

There was an impressive reduction of 34 minutes in the overall median Door to Balloon Time (DTBT) since the commencement of this system redesign process, which was considered statistically significant with a p value of <0.001 (graph 1). This median DTBT included all patients admitted in and out of operating hours, any day of the week, encompassing the various types of presentations, i.e. self presentation, ambulance presentation or pre hospital notification.

The percentage of patients with STEMI treated within the recommended 90-minute timeframe also demonstrated a significant difference starting at only 34% before process change and increasing to 70%, an improvement of 36% (graph 2).

The most encouraging aspect to those involved in any system change is to be able to maintain the improvements over time. Graph 3 depicts the median DTBTs against total number of cases for that specific bi-month period, and clearly demonstrates the sustained effort of maintaining the DTBT under the 90 minute guideline.


It was a high priority within the team that the audit process and system redesign remained constructive rather than critical with an emphasis on the efforts of the teamwork displayed. These results have provided a platform to build upon and improve clinical practice. Contextual factors such as effectiveness of teamwork and organisational environment influence the likelihood of change. Key to our success was engaging all key stakeholders to communicate results and identify a plan of action that identified multifaceted interventions to address issues, thus creating a valuable feedback loop, as feedback alone has little effect as a method of implementing change.11 This feedback loop continues to involve not only bimonthly emails to the ED, CCL and Cardiology and Ambulance Victoria team as a whole, but extends to include regular feedback sessions presenting individual case studies of the STEMI patients i.e. the presenting 12 lead ECG, the corresponding coronary angiography and the subsequent intervention.

Identification of clinical champions in the work environment is also central to the success of implementing change.13 Utilising the clinical nurse educators from the emergency department to leverage the effect of these education sessions has provided this type of facilitation.

Improvement in DTBTs demonstrates how approaches to improve care can be rapidly integrated into practice.13 In hospitals that have achieved notable improvements in DTBT there is identification of a commitment to an explicit goal to improve DTBT, flexibility in implementation, dedicated clinical leaders, along with innovative protocols and collaborative teams.14 The attributes of this clinical audit team have similarities to the aforementioned characteristics, which hopefully will ensure continued improvement in this quality assurance project.


Ongoing audit and system redesign can dramatically reduce DTBTs and unite the multidisciplinary teams both in the hospital and community by assisting them to continually evaluate performance against evidence based targets. While the treatment for STEMI may have evolved over the last two decades, the notion of ‘time is muscle’ has never been more relevant.

Reference List:

  1. Rathore SS, Curtis JP, Chen J, Wang Y, Nallamothu BK, Epstein AJ, Krumholz H (2009) “Association of door to balloon time and mortality in patients admitted to hospital with ST elevation myocardial infarction: national cohort study” BMJ, 338;b1807.

  2. Heart Foundation & The Cardiac Society of Australia and New Zealand (2006) “Guidelines for the management of acute coronary syndromes 2006”, MJA supplement, Vol 184, Number 8.

  3. Keeley et al (2003) “ Primary Angioplasty vs IV thrombolysis for AMI: a quantative review of 23 randomised trails”, Lancet, 361: (9351):13-20

  4. Cannon CP, Gibson CM, Lambrew T et al, (2000) “Relationship of symptom-onset-balloon-time and door-to-balloon- time with mortality in patients undergoing angioplasty for acute Myocardial Infarction”, JAMA, 283(22):2941-2947

  5. McNamara RL, Wong Y, Herrin J, Curtis JP, Bradley EH, Magid DJ, Peterson ED, Blaney M, Frederick PD, Krumholz H (2005) ‘Effect of Door to Balloon time on Mortality in Patients with ST segment Elevation Myocardial Infarction” JACC, 47: 2180-2186.

  6. Rathore SS, Curtis JP, Chen J, Wang Y, Nallamothu BK, Epstein AJ, Krumholz H (2009) ‘ Association of door to balloon time and mortality in patients admitted to hospital with ST elevation myocardial infarction: national cohort study” BMJ, 338;b1807.

  7. Borbasi S, Jackson D, Lockwood C, (2005) “Undertaking a clinical audit” in Courtney, M (2005) “ Evidence for Nursing Practice “ Elsevier, Churchill, Livingstone

  8. Morell C and Harvey G (2003) “The clinical audit handbook-improving the quality of health care”, Balliere Tindall.

  9. National Institute for Clinical Excellence: NICE (2002) ‘Principles for Best Practice in Clinical, Radcliffe Medical Press Ltd.

  10. Hutchison AW, Malaipan Y, Jarvie I, Barger B, Watkins E, Braitberg G, Kambourakis T, Cameron JD, Meredith IT (2009) “Prehospital 12 lead ECG to Triage ST-Elevation Myocardial Infarction and Emergency Department Activation of the Infarct Team Significantly Improves Door-To-Balloon Times”, Cardiovascular Intervention; 2:528-534

  11. National Institute for Clinical Excellence: NICE (2002) ‘Principles for Best Practice in Clinical, Radcliffe Medical Press Ltd.

  12. Soo S, Berta W and Baker G (2009) “Role of Champions in the Implementation of Patient Safety Practice Change” Health Care Quarterly, Vol 12, special issue.

  13. Krumholz HM, Herrin J, Miller LE, Drye EE et al (2011) “Improvements in Door to Balloon Time In the United States, 2005-2010”, Circulation, 124:1038-1045.

  14. Bradley EH, Curry LA, Webster TR, Mattera JA, Roumanis SA, Radford MJ, McNamara RL, Barton BA, Berg DN, and Krumholz HM (2006) ‘Achieving rapid Door to Balloon Times: How top hospitals improve complex clinical systems’, Circulation. 113: 1079-1085

About the authors

Ms Lorelle Martin, Clinical Support Nurse/Clinical Nurse Specialist, Cardiac Catheterisation Laboratories, Austin Health Lorelle has been nursing for 17 years, including an overseas stint in London and Edinburgh for 7 years, with a strong emphasis and passion for the areas of Coronary Care and the Cardiac Catheterisation Laboratory.

She is currently completing her Master of Nursing in Cardiac Care at La Trobe University in Melbourne, and project managed the ‘Cath Lab Code’ process change described in this article.

Lorelle believes that a team approach to achieving clinical goals is instrumental in delivering patient focused care that is high in quality and reliability.

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