Nuclear Cardiology in the COVID-19 pandemic.

SARS-CoV-2 infection has a very important relationship with cardiovascular disease. Since the beginning of the pandemic, a close relationship has been observed between cardiovascular comorbidity and a worse prognosis in COVID-19 patients. The study of the pathophysiology of SARS-CoV-2 infection and cardiovascular disease suggests several concomitant hypotheses: direct myocardial damage by the virus, hypoxemia secondary to respiratory failure, inflammatory response to infection and/or thromboembolic phenomena. Cardiovascular damage can manifest in the acute phase of infection with acute myocardial infarction, myocarditis, arrhythmias…, during this phase Nuclear Cardiology procedures have not played a determining role in the diagnosis and management of these patients. On the other hand, in the subacute phase of the infection and in the post-acute COVID syndrome, Nuclear Cardiology seems to shed light on what happens in the cardiovascular system in this phase of the disease. The COVID-19 pandemic has represented a great challenge for health systems, with a significant reduction in non-urgent diagnostic procedures with the aim of reducing the risk of transmission to patients and health personnel. Nuclear Cardiology has not been an exception. In addition to the prioritization of urgent/non-deferrable procedures and general screening, hygiene and distance measures, the main organizations and scientific societies of Nuclear Medicine and Nuclear Cardiology released recommendations and guidelines for safe practice, introducing significant changes in myocardial perfusion SPECT protocols.

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

PURPOSE: Regadenoson, an A2A 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.

Comparative study of the safety of regadenoson between patients with mild/moderate chronic obstructive pulmonary disease and asthma.

PURPOSE: To compare the safety of regadenoson, a selective agonist of A2A adenosine receptors, combined with low-level exercise, between subjects with mild/moderate chronic obstructive pulmonary disease (COPD) and asthma referred for myocardial perfusion imaging (MPI). METHODS: We studied 116 patients, of whom 67 had COPD and 49 asthma (62 % men, mean age 68.3 ± 11.3 years, range 31 - 87 years). Patient demographics, past medical history, medications, clinical symptoms during stress and changes in blood pressure (BP) and heart rate (HR) were evaluated. RESULTS: Both groups were comparable with regard to hypertension, dyslipidaemia, diabetes and medications with the exception of a higher rate of use of anticholinergics in patients with COPD and of antileukotrienes in asthmatics (58.2 % vs. 28.6 % and 1.5 % vs. 14.3 %, respectively; all p < 0.01). There was a higher incidence of dyspnoea in COPD patients and of headache and feeling hot in asthmatic patients (40.3 % vs. 22.4 %, 6 % vs. 18.4 % and 10.4 % vs. 26.5 %, respectively; all p < 0.05). Although there was no difference in the incidence of other adverse events, we observed a higher frequency in asthmatics of flushing, dry mouth, sweating and fatigue (1.5 % vs. 6.1 %, 14.9 % vs. 24.5 %, 0 % vs. 4.1 % and 37.3 % vs. 49 %, respectively). Adverse events were self-limiting, except in three patients who suffered persistent dyspnoea (2 of 67 COPD patients; 1 of 49 asthma patients) requiring theophylline administration. We observed no significant changes in BP among either group, but there was a tendency towards a higher increase in systolic BP in COPD patients following regadenoson administration (148.3 ± 27.6 vs. 154.6 ± 31.0 mmHg, p = 0.056). CONCLUSION: This study showed a good safety profile in our series of COPD and asthma patients undergoing MPI. Regadenoson was well tolerated by all patients, with dyspnoea, headache and feeling hot showing differences between groups.