Effect of proton pump inhibitors and other commonly prescribed drugs on rescanning of patients undergoing myocardial perfusion imaging: a case-control study.

OBJECTIVES: Proton pump inhibitor use is associated with increased gastric wall activity on myocardial perfusion imaging; however, the clinical impact is unknown. We sought to determine the association of the use of proton pump inhibitors and nine other commonly prescribed classes of medications on the risk of rescanning patients undergoing myocardial perfusion imaging. METHODS: A matched case-control study was performed including 337 rescanned cases and 337 same-day controls from a total of 5432 patients undergoing myocardial perfusion imaging (MPI) over a 4-year period. RESULTS: The odds of rescanning was higher in patients taking a proton pump inhibitor than those not [adjusted odds ratio (OR), 1.6; 95% confidence interval (CI), 1.1-2.2] and in those taking an angiotensin-converting enzyme inhibitor than those not (adjusted OR, 1.5; 95% CI, 1.0-2.2) adjusted for age, sex and BMI category. Eight other commonly prescribed medications showed no associations with rescanning. Among the cases of rescanning, the culprit organ site of extracardiac activity was the left lobe of the liver, 48%; gastric wall, 31%; gastric lumen, 12%; spleen, 7% and bowel <1%. Proton pump inhibitor use was strongly associated with rescanning due to gastric wall uptake (adjusted OR, 6.3; 95% CI, 2.8-14.1) but not the other causes of rescanning. CONCLUSIONS: Proton pump inhibitor use and angiotensin-converting enzyme inhibitor use are associated with an increased risk of rescanning of patients undergoing MPI. Gastric wall activity is likely to account for the excess cases of rescanning in those taking a proton pump inhibitor.

Interaction between the effects of proton pump inhibitors and aspirin on gastric wall sestamibi uptake on myocardial perfusion imaging.

BACKGROUND: Increased gastric wall activity on myocardial perfusion imaging (MPI) is associated with proton pump inhibitor (PPI) therapy; however, the mechanism is unknown. We proposed a role for gastric mucosal prostaglandin synthesis and asked whether concurrent use of aspirin would antagonize this effect. METHODS: An observational study was performed of 319 patients undergoing technetium-99m sestamibi (MIBI) rest/stress MPI. We assessed the effects of taking PPIs, aspirin and their interaction on the principle outcome of clinically significant gastric wall activity. RESULTS: The outcome was observed in 13% of patients taking neither a PPI nor aspirin, 22% of those taking aspirin only, 51% taking a PPI only and 33% of those taking both. Adjusted odd ratios (95% confidence intervals) were 6.3 (CI 2.8-14.0; p < .001) for taking a PPI only, 1.8 (CI 0.8-3.9; p = .16) for taking aspirin only, and 3.0 (CI 1.4-6.5; p = .005) for taking the combination of a PPI and aspirin. There was evidence of negative statistical interaction between the two drug effects using additive (p = .006) and multiplicative (p = .016) scales. CONCLUSIONS: PPI use was strongly associated with enhanced gastric wall activity on MPI; however, concurrent aspirin appears to reduce the effect. Enhanced local prostaglandin synthesis may mediate the PPI effect.

An audit of ventilation and perfusion SPECT reporting for the diagnosis of pulmonary embolism in a tertiary cardiothoracic centre.

The aim of the study was to identify reporting patterns of ventilation and perfusion single-photon emission computed tomography (V/Q SPECT) scans done in our department over 3 months in 2016. Factors impacting on reporting and patient groups that would most benefit from the addition of low-dose computed tomography (CT) to V/Q SPECT were analysed. Among 178 patients, 173 (97.2%) had a definitive (positive/negative) report and 2.8% had an equivocal report. As the majority of the equivocal reports were seen in patients aged ≥70 years, we believe that addition of low-dose CT with V/Q SPECT to this patient group will reduce the non-diagnostic rate.