Caffeine does not significantly reduce the sensitivity of vasodilator stress myocardial perfusion imaging

Caffeine consumed prior to cardiac stress testing may affect diagnostic accuracy of nuclear medicine myocardial imaging of myocardial ischemia: A systematic review and meta-analysis

BACKGROUND

Myocardial perfusion imaging (MPI) is a well-established, non-invasive imaging procedure for the diagnosis and evaluation of patients with known or suspected coronary artery disease. With the increasing use of pharmacologic stress agents in myocardial perfusion imaging, strict preparation, including caffeine abstinence, is required. The aim of this review was to determine the effect of caffeine consumed prior to nuclear cardiac stress testing on the diagnostic accuracy.

METHODS

Medline, Embase and CINAHL were searched from the earliest available time until August 2022. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies version 2. Data pertaining to diagnostic accuracy were analysed using meta-analysis where appropriate and overall certainty of evidence evaluated using the Grades of Research, Assessment, Development and Evaluation approach.

RESULTS

Six studies (307 participants) from a yield of 735 articles were identified. Meta-analysis of two studies found no difference in the left ventricular ejection fraction of patients pre and post caffeine consumption (MD -0.31 %, 95% CI -4.32% to 3.7%). Meta-analysis of three studies found there was uncertainty as to whether caffeine consumption affected reversibility (MD -2.16 segments 95% CI -4.61 to 0.28) and descriptive summary of three studies found mixed results for size of stress defects.

CONCLUSION

The low quality evidence synthesized in this systematic review suggests caffeine may affect the diagnostic accuracy in myocardial perfusion imaging for ischemia detection in patients with chest pain and intermediate-to-high risk of coronary artery disease.

Linear concentration-response relationship of serum caffeine with adenosine-induced fractional flow reserve overestimation: a comparison with papaverine

BACKGROUND

Caffeine intake from one cup of coffee one hour before adenosine stress tests, corresponding to serum caffeine levels of 3-4 mg/L, is thought to be acceptable for non-invasive imaging.

AIMS

We aimed to elucidate whether serum caffeine is independently associated with adenosine-induced fractional flow reserve (FFR) overestimation and their concentration-response relationship.

METHODS

FFR was measured using adenosine (FFRADN) and papaverine (FFRPAP) in 209 patients. FFRADN overestimation was defined as FFRADN - FFRPAP. The locally weighted scatterplot smoothing (LOWESS) approach was applied to evaluate the relationship between serum caffeine level and FFRADN overestimation. Multiple regression analysis was used to determine independent factors associated with FFRADN overestimation.

RESULTS

Caffeine was ingested at <12 hours in 85 patients, at 12-24 hours in 35 patients, and at >24 hours in 89 patients. Multiple regression analysis identified serum caffeine level as the strongest factor associated with FFRADN overestimation (p<0.001). The LOWESS curve demonstrated that FFRADN overestimation started from just above the lower detection limit of serum caffeine and increased approximately 0.01 FFR unit per 1 mg/L increase in serum caffeine level with a linear relationship. The 90th percentile of serum caffeine levels for the ≤12-hour, the 12-24-hour, and the >24-hour groups corresponded to FFRADN overestimations by 0.06, 0.03, and 0.02, respectively.

CONCLUSIONS

Serum caffeine overestimates FFRADN values in a linear concentration-response manner. FFRADN overestimation occurs at much lower serum caffeine levels than those that were previously believed. Our results highlight that standardised caffeine control is required for reliable adenosine-induced FFR measurements.

Effects of Caffeine on Myocardial Blood Flow: A Systematic Review

Background. Caffeine is one of the most widely consumed stimulants worldwide. It is a well-recognized antagonist of adenosine and a potential cause of false-negative functional measurements during vasodilator myocardial perfusion. The aim of this systematic review is to summarize the evidence regarding the effects of caffeine intake on functional measurements of myocardial perfusion in patients with suspected coronary artery disease. Pubmed, Web of Science, and Embase were searched using a predefined electronic search strategy. Participants—healthy subjects or patients with known or suspected CAD. Comparisons—recent caffeine intake versus no caffeine intake. Outcomes—measurements of functional myocardial perfusion. Study design—observational. Fourteen studies were deemed eligible for this systematic review. There was a wide range of variability in study design with varying imaging modalities, vasodilator agents, serum concentrations of caffeine, and primary outcome measurements. The available data indicate a significant influence of recent caffeine intake on cardiac perfusion measurements during adenosine and dipyridamole induced hyperemia. These effects have the potential to affect the clinical decision making by re-classification to different risk-categories.

Multi-modality imaging: Bird's eye view from the 2017 American Heart Association Scientific Sessions

This review summarizes key imaging studies that were presented in the American Heart Association Scientific Sessions 2017 related to the fields of nuclear cardiology, cardiac computed tomography, cardiac magnetic resonance, and echocardiography. The aim of this bird's eye view is to inform readers about multiple studies reported at the meeting from these different imaging modalities. While such a review is most useful for those that did not attend the conference, we find that a general overview may also be useful to those that did since it is often difficult to get exposure to many abstracts at large meetings. The review, therefore, aims to help readers stay updated on the newest imaging studies presented at the meeting and will hopefully stimulate new ideas for future research in imaging.