The Influence of a Normal Myocardial Perfusion SPECT on Prescription of Preventive Cardiovascular Medications and Patients’ Adherence - The 63rd Annual Conference of the Israel Heart Society in association with the Israel Society of Cardiothoracic Surgery 12-13 April 2016, David Intercontinental Hotel, Tel-Aviv, Israel

ARYEH SHALEV ^1,2 Noga Michnovsky ² Arik Wolak ³ Victor Novack ⁴ Ronen Toledano ⁴ Yaakov Henkin ^1,2

¹Cardiology Department, Soroka University Medical Center, Be'er Sheva
²Faculty of Health Sciences, The Joyce & Irving Goldman Medical School, Ben Gurion University of The Negev, Be'er Sheva, Israel
³Cardiac Imaging Unit, Cardiology Department, Sha'are Zedek Medical Center, Jerusalem
⁴Clinical Research Center, Soroka University Medical Center, Ben Gurion University of The Negev, Be'er Sheva, Israel

Background: Abnormal SPECT myocardial perfusion imaging (SPECT-MPI) denotes obstructive coronary artery disease (CAD) and is predictive of cardiovascular events. Conversely, a normal scan is associated with a low short-term risk. An abnormal SPECT-MPI has been shown to lead to enhanced medical therapy and patients’ adherence. We hypothesized that a normal SPECT-MPI, in subjects without known CAD, would lead to a decrease in preventive therapy.

Methods: a retrospective cohort study that included all subjects without known CAD, that had their first SPECT-MPI scan at Soroka-Medical-Center between 1997-2008. Baseline characteristics, prescription retrieval of aspirin and a statin from the HMO pharmacy within 1 year from SPECT-MPI, and health status, were retrieved from the central database of Clalit-Health-Services. Medication non-adherence was defined as <50% retrieval. We compared subjects with normal scan (summed stress score - SSS<2) vs. abnormal scan. Parsimonious cox regression model was utilized to assess multiple variables associated with increased risk of myocardial infarction and cardiac mortality within 8 years after SPECT-MPI and with 1-year drug cessation.

Results: 11,642 subjects had a normal SPECT-MPI, and in comparison to subjects with abnormal scan (n=6892) were predominantly female (56.6% vs. 24.7%,p<0.001), at younger age (64.1±11.2 vs. 65.4±10.8,p<0.001) and were less likely to be smokers (13.2% vs. 15.5%, p<0.001). Statin and aspirin use at 1-year period post-scan were both increased in the study group in comparison to the pre-scan period (50.6% vs. 41.5% pre-scan for statin, and 49.6% vs. 41.5% for aspirin, p