CLINICAL RESEARCH: CARDIAC IMAGING
The Coronary Artery Calcium Score and Stress Myocardial Perfusion Imaging Provide Independent and Complementary Prediction of Cardiac Risk
Su Min Chang, MD,
Faisal Nabi, MD,
Jiaqiong Xu, PhD,
Leif E. Peterson, PhD,
Arup Achari, MD,
Craig M. Pratt, MD and
John J. Mahmarian, MD*
Methodist DeBakey Heart and Vascular Center and The Methodist Hospital Research Institute, The Methodist Hospital, Houston, Texas
Manuscript received March 19, 2009;
revised manuscript received May 7, 2009,
accepted May 25, 2009.
* Reprint requests and correspondence: Dr. John J. Mahmarian, Methodist DeBakey Heart and Vascular Center, 6550 Fannin Street, Suite 677, Houston, Texas 77030 (Email: jmahmarian{at}tmhs.org).
Objectives: This study sought to examine the relationship between coronary artery calcium score (CACS) and single-photon emission computed tomography (SPECT) results for predicting the short- and long-term risk of cardiac events.
Background: The CACS and SPECT results both provide important prognostic information. It is unclear whether integrating these tests will better predict patient outcome.
Methods: We followed-up 1,126 generally asymptomatic subjects without previous cardiovascular disease who had a CACS and stress SPECT scan performed within a close time period (median 56 days). The median follow-up was 6.9 years. End points analyzed were total cardiac events and all-cause death/myocardial infarction (MI).
Results: An abnormal SPECT result increased with increasing CACS from <1% (CACS  10) to 29% (CACS >400) (p < 0.001). Total cardiac events and death/MI also increased with increasing CACS and abnormal SPECT results (p < 0.001). In subjects with a normal SPECT result, CACS added incremental prognostic information, with a 3.55-fold relative increase for any cardiac event (2.75-fold for death/MI) when the CACS was severe (>400) versus minimal (10). Separation of the survival curves occurred at 3 years after initial testing for all cardiac events and at 5 years for death/MI.
Conclusions: The CACS and SPECT findings are independent and complementary predictors of short- and long-term cardiac events. Despite a normal SPECT result, a severe CACS identifies subjects at high long-term cardiac risk. After a normal SPECT result, our findings support performing a CACS in patients who are at intermediate or high clinical risk for coronary artery disease to better define those who will have a high long-term risk for adverse cardiac events.
Key Words: coronary artery calcium • myocardial perfusion imaging • risk stratification
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Abbreviations and Acronyms
| | CACS = coronary artery calcium score | | CAD = coronary artery disease | | ECG = electrocardiogram/electrocardiographic | | LV = left ventricular | | MI = myocardial infarction | | PDS = perfusion defect size | | SPECT = single-photon emission computed tomography |
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J. Am. Coll. Cardiol. 2009 54: A32.
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