home | ABOUT THE IAC | THE IAC DIVISIONS | ACCREDITATION | IAC NEWSLETTER | EXHIBIT SCHEDULE | CONTACT THE IAC

IAC Newsletter

In today's health care climate, the vast majority of nuclear medicine laboratories are searching for ways to perform higher numbers of nuclear cardiology examinations in less time. As laboratories are considering methods for increasing their efficiency, they are likely to deliberate the use of a shortened adenosine protocol.

Since the inception of the ICANL accreditation process in 1997, the standards and guidelines have been based upon published literature, primarily from the sponsoring organizations. As stated in the 2007 ICANL Standards for Nuclear Cardiology, Nuclear Medicine and PET Accreditation, "All exercise/pharmacologic protocols must follow accepted practices, such as the report published by the American College of Cardiology/American Heart Association Task Force on Practice Guidelines, Exercise Testing: ACC/AHA 2002 Guideline Update for Exercise Testing: Summary Article (or have published justification for variance)." The ICANL Board of Directors relies upon such published guidelines when evaluating laboratories for accreditation, to best ensure quality patient care.

The 3-minute adenosine protocol is a relatively new approach that is being considered by many laboratories. It is important to point out that the 3-minute adenosine protocol was not recommended in the recent late 2007 clinical update to the American Society of Nuclear Cardiology (ASNC) Imaging Guidelines1 for Nuclear Cardiology Procedures titled "Adenosine Stress Protocols For Myocardial Perfusion Imaging".2 As the 3-minute protocol is not recommended by ASNC, laboratories seeking accreditation by the ICANL will not be granted accreditation if this abbreviated protocol is used.

In recently published literature, a reduced adenosine infusion length in comparison to the standard infusion rate recommended in the ASNC Imaging Guidelines for Nuclear Cardiology Procedures has been used. Both a 3- and 4-minute adenosine infusion protocol have been proposed. It is believed that the shorter protocols will result in a reduction in time, cost and symptoms.

The time to maximal vasodilation with adenosine is 84 +/- 46 seconds. The time to recovery from peak dilation once the adenosine infusion is stopped is 145 +/- 67 seconds. Numerous studies have documented not only the safety but also the diagnostic accuracy of the ASNC recommended adenosine continuous 6-minute infusion of 140 ug/kg/min.

For more than 10 years, many laboratories have used the shorter 4-minute protocol proposed by O'Keefe et al3 at 140 ug/kg/min. Based upon the kinetics of adenosine and the history of favorable results, the current ASNC Imaging Guidelines for Nuclear Cardiology Procedures state that the 4-minute infusion is a reasonable alternative to the recommended 6-minute infusion. As the 4-minute protocol is considered reasonable according to published ASNC guidelines, laboratories seeking accreditation by the ICANL can achieve accreditation using this abbreviated protocol.

Using the 4-minute protocol, the adenosine is infused and the tracer is injected at two minutes. The adenosine is then infused for an additional two minutes, allowing two minutes circulation time for the tracer. The update further states that variations of the protocol with infusion longer than 4 minutes are acceptable as long as the adenosine infusion is continued for at least two minutes after the tracer injection.

The 3-minute protocol, which also infuses the adenosine at 140 ug/kg/min, is not recommended by ASNC, given the current body of research. The kinetic properties of adenosine suggest that the shorter infusion does not provide adequate time for infusion and tracer administration to achieve a good-quality and reproducible vasodilator response.

As both technology and research continue to advance, the ICANL Board of Directors encourages laboratories to seek and evaluate methods for improving efficiency and adopt protocols that are validated through published literature released by the sponsoring organizations, thus contributing to ongoing improvements in overall patient care.

1 DePuey EG, Corbett Jr, Friedman JD, Goldstein RA, Henzlova MJ, Hansen DL, et al. Imaging guidelines for nuclear cardiology procedures - November 2007. American Society of Nuclear Cardiology. Available from: http://www.asnc.org/imageuploads/Imaging%20Guidelines.pdf. Accessed February 20, 2008.

2 Sabahat B, Ficaro EP, McCallister BD, ASNC Clinical Update: Adenosine stress protocols for myocardial perfusion imaging. Available from: http://www.asnc.org/imageuploads/AdenosineClinicalUpdate0607.pdf. Accessed February 20, 2008.

3 O'Keefe JH, Bateman TM, Handlin LR, Barnhart CS. Four- versus 6-minute infusion protocol for adenosine thallium-201 single photon emission computed tomography imaging. Am Heart J 1995;129:482-7.

4 Treuth MG, Reyes GA, He Zx, et al. Tolerance and diagnostic accuracy of an abbreviated adenosine infusion for myocardial scintigraphy; a randomized, prospective study. J Nucl Card 2001;8:548-54.