Influence of body mass index and type of low-level exercise on the side effect profile of regadenoson

PURPOSE

Regadenoson, an A_2A adenosine receptor pharmacologic stress agent for radionuclide myocardial perfusion imaging (MPI), is administered as a single, fixed dose. We studied the side effect profile of regadenoson combined with two types of low-level exercise, according to body mass index (BMI).

METHODS

Three hundred and fifty-six patients (46.1% men, mean age 67.7±10.7 years, range 31-90 years) underwent regadenoson stress testing combined with low-level exercise. Subjects were classified according to BMI as normal, overweight, or obese, and the type of low-level exercise performed as walking on the treadmill (TE group, n=190) or forcefully swinging legs while sitting (SS group, n=166). Patients' demographics, medical history, clinical symptoms during stress, changes in ECG, oxygen saturation (SatO₂), systolic blood pressure (SBP), and heart rate (HR) were evaluated.

RESULTS

Groups were comparable (p=ns) with regard to cardiovascular risks factors. The incidence of side effects was similar across BMI (p=ns), although the TE patients showed improved profiles over those with SS exercise, with a significantly lower incidence of flushing, dizziness and nausea/gastrointestinal discomfort (12.9% vs. 28.4%; 19.9% vs. 33.4%; 11.4% vs. 19.2%, respectively; all p<0.05). Regarding the hemodynamic response, we did not observe significant changes in SBP and HR after regadenoson administration across BMI categories. Comparing the TE and SS groups, no significant changes were observed in SBP, but there was a higher increase in HR in the TE group (p<0.05).

CONCLUSIONS

Regadenoson in combination with low-level exercise is safe and well tolerated over a wide range of BMI, with TE exercise showing a better side effect profile than SS.

Relation of Fasting Triglyceride-Rich Lipoprotein Cholesterol to Coronary Artery Calcium Score (from the ELSA-Brasil Study)

Although low-density lipoprotein cholesterol (LDL-C) is widely accepted as the principal lipid fraction associated with atherosclerosis, emerging evidence suggests a causal relation between lifelong elevations in triglyceride-rich lipoprotein cholesterol (TRL-C) and cardiovascular disease (CVD) in genetic studies. To provide further evidence for the potential relevance of TRL-C and atherosclerosis, we have evaluated the relation between TRL-C and coronary artery calcium (CAC) score. We included 3,845 subjects (49.9 ± 8.4 years, 54% women) who had no history of CVD, were not using lipid-lowering medications, and underwent CAC evaluation. We assessed the relation between increasing fasting TRL-C and the graded increase in CAC and to what extent TRL-C were independently associated with CAC over and above LDL-C using logistic regression models. Overall, 973 (25%) of the participants had a CAC >0 and 308 (8%) had a CAC >100. The median TRL-C level was 22 mg/dL (IQR 16 to 32). Subjects with CAC >0 had higher TRL-C levels than those with CAC = 0 (p <0.001). Similarly, subjects with CAC >0 had higher levels of LDL-C, non-high-density lipoprotein cholesterol, and lower high-density lipoprotein cholesterol (all p <0.001). After multivariate adjustment, log-transformed TRL-C remained associated with the presence and severity of CAC (all p <0.05). When TRL-C was added to models that contained demographic factors and conventional lipids, it significantly improved the model to predict the presence of CAC >0 (p = 0.01). In conclusion, in a large cohort of asymptomatic subjects, TRL-C was associated with subclinical atherosclerosis supporting a potentially causal role in CVD.