- Posted on: 6/19/08
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Commentary: I. ‘False Positives’
In the December 2007 issue of Cath Lab Digest, I provided an editorial comment to the exceptional quality of scientific work that was performed with short door-to-balloon (D2B) ST-elevation myocardial infarction (STEMI) interventions at St. Episcopal Hospital in Houston, Texas. In that note, besides complementing the institution for its fine work, I cautioned against complacency towards proceeding with emergent cath/percutaneous coronary intervention (PCI), citing precisely the high false alarms that have been mentioned in this outstanding study reported by Dr. David Larson. By the American College of Cardiology (ACC)/American Heart Association (AHA) criteria for primary stenting, the rates for these ‘false alarms’ should be less than 15%. By this standard, the 14% of the false alarms cited by Dr. Larson at the Minneapolis Heart Institute Foundation at Abbott Northwestern Hospital is quite acceptable. Yet the authors have creditably deemed these rates as unacceptably high. The reader must also be made aware that the Minneapolis experience, with its Spoke and Wheel, pharmaco-invasive model of triage for primary PCI is one of the most advanced programs in the world, and one that has established superb guidelines and pathways for very effective triage for STEMI patients. I emphasize the excellent caliber of the work at Minneapolis Heart Institute since their high false alarm rates may actually be some of the lowest in the nation, and that the problems of these false alarms may be much higher at other institutions, in particular, at low-volume STEMI institutions. It must also be understood that a clear dichotomy exists between STEMI intervention results during ‘off’ hours and ‘on’ hours. Institutions providing 24/7 primary PCI struggle to achieve D2B times <90 minutes during off hours. Although large institutions possessing great expertise in short D2B interventions have not specifically reported on false alarm rates between off and on hours, it can be expected that just as the D2B times are longer during off hours, the rates of false alarms may be expected to be higher during off hours. This provides a double disservice to the patient presenting with STEMI during off hours – not only will the primary PCI be delayed, there is also a higher likelihood of emergently proceeding with the procedure in the absence of a “culprit lesion.” The very high costs involved with these false alarms are also a matter of considerable concern, as is the issue of the false alarms causing a crisis in confidence in the individual institutions. It is very frustrating for the cardiac catheterization laboratory to rush in at 3 am for a normal cath.
There are several ways for individual institutions to get their arms around this burgeoning problem. It is obvious that the emergency department (ED) physicians are under great stress to diagnose STEMI – they have to be very accurate and very fast. It is a new responsibility that has been assigned to them quite rapidly. Suddenly, several low-volume institutions have pronounced themselves “Centers of Excellence” providing 24/7 STEMI interventions. Billboards of similar pronouncements have begun cropping on highways as these institutions are riding the bandwagons without mandating quality and without placing in position top-notch ED physicians. Previously, it was routine that the ED physicians were consulting a cardiologist prior to beginning management for STEMI. In the present set-up at several institutions, with the enormous demands placed to meet D2B times, the ED department is all too often rushing to press “Code Heart” and declare itself a winner, achieving high success in low D2B times. The other essential coordinate of quality, the false alarms, have been all too often ignored.
In my upcoming “Textbook of STEMI Interventions,” several contributing authors as well as I have strongly emphasized the need to monitor the false alarm rates. We have declared these rates to be the best parameters of measuring the efficacy of a STEMI program. The D2B time is an effective measure of the process (emergency medical services [EMS] + ED + cardiovascular laboratory [CVL]), whereas the false alarm rates are excellent ways to measure the accuracy and quality of the ED, and sometimes the EMS — at institutions where early activation of the CVL is being performed collectively between these two affiliates. In relationship to this critical topic, administrations and medical staff must mandate high caliber for ED physicians that would participate in STEMI programs. Rigorous training in EKG interpretation is the cornerstone of this new role and continuous quality improvement (CQI) processes must be rigid in this assurance. To be perfectly candid, if any institution cannot provide such quality ED physicians, it has no business in declaring its ability to perform 24/7 STEMI interventions. In a situation where the high accuracy of the ED physician cannot be ensured, the institution must seriously consider to reverting to the time-tested method of the cardiologist evaluating the presenting EKG.
II. Commentary: We Have Picked the Low-Hanging Fruit! Now What?
Dan Scharbach, Regional Director of Invasive Cardiovascular Services at Providence Health System in Portland, Oregon, has chronicled an exceptional review of the door-to-balloon (D2B) performance within the Portland Service Area. He has elaborated on critical steps that can result in a highly effective pathway that will consistently achieve short D2B times. The critical role of the ST-elevation myocardial infarction (STEMI) coordinator has been highlighted and a physician champion has been mentioned as the force behind a very successful endeavor. The importance of teamwork and clear communication has been appropriately emphasized and an excellent observation has been made to use the American College of Cardiology (ACC) guidelines as the best template for institutions to base their D2B programs upon. Finally, Mr. Scharbach poignantly opens up the forum to seek recommendations from others, therein prompting this review.
Cath Lab Digest now has a forum for discussing this very important topic, echoing similar interest at both national and international cardiology meetings. Several institutions are regularly reporting their exceptional results in achieving the ACC/ American Heart Association (AHA) guidelines of successful recanalization of the infarct-related artery (IRA) within 90 minutes. What began as a massive challenge to hospital systems and processes when the guidelines for D2B times were lowered to 90 minutes from 120 minutes is no longer considered an impossible chore. As a result, thousands of patients presenting nationwide are getting exceptional care from successful reperfusion within the “golden hour.” Unique integrations of hospital processes and indigenous solutions to local challenges are being reported by both high and low-volume percutaneous coronary intervention (PCI) institutions. Coordination between the emergency department (ED) and cardiovascular laboratory (CVL) is occurring at these institutions, and there is seamless transfer and transition of medical and nursing care as the patient is rushed through two very different departments of a hospital. In this aspect, the creation of a charismatic STEMI coordinator is critical and we strongly endorse the role of this individual. We also suggest regular inter-departmental meetings that review every patient that fails to meet the D2B deadline, identify the precise source of delay and seek implementations to correct the anomaly.
The above measures and the prudent pathways enunciated by Mr. Scharbach will catch most of the low-hanging fruit in short D2B STEMI interventions. Indeed, achieving this is mandatory and institutions should rapidly reach a status of achieving more than 80% success in meeting D2B times < 90 minutes and ‘false alarm’; rates of < 15%. Once this is achieved, the harder task begins as additional progress requires further intensification of processes, discipline and resource allocation. Further improvements in the success rates will undoubtedly be slower and frustrating, as is eloquently illustrated by Mr. Scharbach. Towards making further progress, we suggest the following strategies:
1. Begin careful review of D2B times during “off” hours — institutions will identify this as the culprit factor limiting overall success. In the ‘False Positives’ commentary in this issue of Cath Lab Digest, we have highlighted the double jeopardy that confronts a patient presenting with STEMI during off hours — there are D2B time delays and higher ‘false alarms’ Consistency in meeting D2B deadlines during off hours requires greater commitment, allocation of additional resources and even greater teamwork. Additional crew on standby will often be required to respond to the presenting patient in the early off hours when there is bound to be confusion as to whether the tired CVL team can push itself or give way to a fresh crew that must press into action immediately.
2. Incorporate the valuable lessons that more experienced centers have accumulated. For this purpose, I strongly endorse the Mayo Clinic and the superb programs that have been developed at the Abbott Northwestern Center in Minneapolis. Imagine how many of the 1,345 patients at the Minneapolis institution presented in the precise adverse “snowstorm” conditions that Mr. Scharbach alluded to in the beginning of his article. The premier Minneapolis institutions have already mastered this challenge. Let us learn from their invaluable experience. In addition to providing exemplary care for STEMI patients, these two superb institutions have created outstanding models of triage and transfer of STEMI patients.
3. Explore early activation pathways that will further erode STEMI delays. The emergency medical system (EMS) process remains a potent opportunity for significant additional gains in short D2B STEMI interventions. The DANish trial in Acute Myocardial Infarction (DANAMI) investigators were the first to recognize this opportunity and seize it by eliminating the redundancies that exist in the early activation of ’code heart’ by EMS.1-3 Several other European centers have also encapsulated these methodologies and in addition to early activation by EMS, they are able to provide pre-hospital thrombolysis to eligible patients. The latter is a vital missing link in the U.S. arsenal in STEMI management. Whether this entails the use of pure fibrinolysis or facilitation with GP 2b/3a antagonists is a moot point that merits greater research. Numerous legal, legislative, financial and institutional barriers are delaying the push for early activation and pre-hospital thrombolysis. The resolution of these difficult issues will not be easy. In the interim, individual institutions may succeed in bypassing some of these hurdles to achieve common-sense ground rules and coordinated activity between the inseparable trio of STEMI care — EMS, ED and CVL.
Finally, we leave the reader with our last caveat on the subject and that is to provide optimal care to the patient, beyond the mandates of the D2B deadlines. Often, as a result of numerous system delays, the D2B time will not be achieved. However, this should not prevent an institution from providing excellent care for the STEMI patient. The exceptional acute and long-term benefits for the individual patient who achieves a successful, early reperfusion of the IRA must not be dampened by an institution’s inability to meet D2B deadlines
Dr. Mehta can be contacted at firstname.lastname@example.org
1. Madsen JK, Grande P, Saunamäki K, et al; on behalf of the DANAMI Study Group. Danish Multicenter Randomized Study of Invasive Versus Conservative Treatment in Patients With Inducible Ischemia After Thrombolysis in Acute Myocardial Infarction (DANAMI). Circulation 1997;96:748-755.
2. Andersen HR, Nielsen TT, Vesterlund T, et al. Danish multicenter randomized study on fibrinolytic therapy versus acute coronary angioplasty in acute myocardial infarction: rationale and design of the DANish trial in Acute Myocardial Infarction-2 (DANAMI-2). Am Heart J 2003 Aug;146(2): 234-241.
3. Busk M, Maeng M, Rasmussen K, et al; for the DANAMI-2 Investigators. The Danish multicentre randomized study of fibrinolytic therapy vs. primary angioplasty in acute myocardial infarction (the DANAMI-2 trial): outcome after 3 years follow-up. Eur Heart J 2007 Oct 23 [Epub ahead of print].