Pulmonary function monitoring during adenosine myocardial perfusion scintigraphy in patients with chronic obstructive pulmonary disease

Hollow core photonic crystal fiber as a reusable Raman biosensor

We report that a single hollow core photonic crystal fiber (HC-PCF) can be used for repetitive characterization of multiple samples by Raman spectroscopy. This was achieved by integrating the HC-PCF to a differential pressure system that allowed effective filling, draining and re-filling of samples into a HC-PCF under identical optical conditions. Consequently, high-quality and reliable spectral data could be obtained which were suitable for multivariate analysis (partial least squares). With the present scheme, we were able to accurately predict different concentrations of heparin and adenosine in serum. Thus the detection scheme as presented here paves a path for the inclusion of HC-PCFs in point-of-care technologies and environmental monitoring where rapid sample characterization is of utmost importance.

Safety of binodenoson, a selective adenosine A2A receptor agonist vasodilator pharmacological stress agent, in healthy subjects with mild intermittent asthma

BACKGROUND

The pharmacological stress agents adenosine and dipyridamole are contraindicated in asthma patients because of the risk of adenosine receptor-mediated bronchospasm. Binodenoson, a selective adenosine A(2A) receptor agonist, produces maximal coronary hyperemia during pharmacological stress testing yet has a low affinity for the adenosine A(1), A(2B), and A(3) receptors that are probably responsible for bronchospasm. This study was conducted to assess the safety of binodenoson in 87 healthy young adult volunteers with documented mild, intermittent asthma.

METHODS AND RESULTS

This study consisted of a dose-escalating, single-blinded phase and a placebo-controlled, double-blinded phase conducted in healthy, young adults with documented mild, intermittent, asthma. In the single-blinded phase, 3 sequential cohorts of 8 subjects received intravenous binodenoson (0.5, 1.0, and 1.5 microg/kg). In the double-blinded phase, commenced after medical review of results from the single-blinded phase, subjects were randomly assigned 2:1 to either binodenoson 1.5 microg/kg (n=41) or placebo (n=22). The primary end point was clinically significant bronchoconstriction, defined as a decrease in forced expiratory volume in 1 second of >/=20% from the preinjection measure. Secondary safety end points were changes from preinjection measure in forced expiratory volume in 1 second, forced vital capacity, and forced expiratory flow during the middle 50% of the forced vital capacity; vital signs; pulse oximetry; and adverse events. Binodenoson caused no clinically significant bronchoconstriction or alterations in pulmonary function parameters and transiently increased heart rate and systolic blood pressure. The most common treatment-emergent adverse events were tachycardia, dizziness, and flushing.

CONCLUSIONS

Binodenoson was safe, well tolerated, and caused no clinically significant bronchoconstriction or pulmonary responses in a small population of healthy subjects with mild, intermittent asthma.

Pharmacological stress myocardial perfusion scintigraphy: use of a modified adenosine protocol in patients with asthma

BACKGROUND

Stress radionuclide myocardial perfusion scintigraphy (MPS) using adenosine pharmacological vasodilatation is the preferred method in many centres because of its convenience, safety and speed. It can, however, cause bronchospasm and hence its use is avoided in patients with known or suspected bronchospasm. Owing to service pressures, we use technologist-led adenosine stressing for patients referred for MPS studies. We use a modified adenosine infusion protocol under medical supervision for patients with asthma to prevent and minimize adenosine-induced bronchospasm. In this study, we audited our use of this modified protocol in asthmatic patients and compared the side-effect profile with the standard adenosine protocol used in nonasthmatic patients.

METHODS

We audited 50 consecutive patients with asthma attending our department for stress MPS. All patients were taking regular inhalers+/-oral steroids. Patients who had exacerbation of asthma requiring hospital admission during the preceding 6 months were excluded. Before commencing the infusion, two inhaled puffs of salbutamol were administered. A modified adenosine infusion protocol was used, starting initially at a rate of 70 microg/kg/min and increasing to the standard 140 microg/kg/min within 1 min and then maintained for a further 5 min. Technetium-99m tetrofosmin was injected at 3 min. Blood pressure (BP), pulse rate (PR), oxygen saturation and ECG were monitored before, during and at the end of the infusion. All side effects were recorded. Fifty-eight consecutive patients without asthma were included as controls and received the standard 140 microg/kg/min infusion over 6 min.

RESULTS

One hundred and eight patients, 50 with asthma and 58 without asthma, were entered into the study. The test was stopped early in two patients (4%) with asthma and 11 patients (19%) without asthma (chi=5.679; P=0.017). Proportionally, more nonasthmatics developed shortness of breath (SOB) (47 of 58, 81% without asthma vs. 35 of 50, 70% with asthma); however, this did not reach statistical significance (chi=1.788, P=NS). Three out of 50 (6%) patients in the asthma group experienced severe SOB but only one of those 50 patients (2%) developed bronchospasm, manifesting as wheeze. In the nonasthma group, five of 58 patients (8.6%) experienced severe SOB but none developed a wheeze. Less flushing (16 of 50, 32% vs. 36 of 58, 62%; P=0.002), dizziness (12 of 50, 24% vs. 26 of 58, 45%; P=0.023) and neck/throat pain (5 of 50, 10% vs. 16 of 58, 28%; P=0.021) was observed in the modified infusion group with asthma compared with the standard infusion group without asthma. Statistical significance was observed in these three side effects. No significant difference in other side effects was noted. A similar decrease in mean diastolic BP, and an increase in mean PR were observed during the infusion in both asthmatic and nonasthmatic groups. The mean systolic BP decreased significantly in nonasthmatic patients (P<0.001) but not in the asthmatic group. No significant change in oxygen saturation was seen during infusion in the asthmatic group.

CONCLUSION

The modified adenosine infusion protocol with salbutamol premedication can be used in patients with asthma. This protocol resulted in fewer side effects and changes in BP and PR in asthmatic patients compared with nonasthmatic patients who received the standard adenosine infusion.

Safety of regadenoson, a selective adenosine A2A agonist, in patients with chronic obstructive pulmonary disease: A randomized, double-blind, placebo-controlled trial (RegCOPD trial)

BACKGROUND

Patients with reactive airways are at risk for adenosine-induced bronchoconstriction, mediated via A(2B) and/or A(3) adenosine receptors.

METHODS AND RESULTS

In this randomized, double-blind, placebo-controlled crossover trial, we examined the safety of regadenoson, a selective adenosine A(2A) receptor agonist, in patients with moderate chronic obstructive pulmonary disease (COPD) (n = 38) and patients with severe COPD (n = 11) with a baseline mean forced expiratory volume in 1 second (FEV(1)) of 1.74 +/- 0.50 L and 1.0 +/- 0.35 L, respectively, 37% of whom had dyspnea during activities of daily living. Patients receiving glucocorticoids or oxygen and those with pretreatment wheezing were included. Short-acting bronchodilators were withheld for at least 8 hours before treatment. No differences emerged between regadenoson and placebo on multiple lung function parameters, including repeated FEV(1) and forced vital capacity, respiratory rate, pulmonary examinations, and oxygen saturation. The mean maximum decline in FEV(1) was 0.11 +/- 0.02 L and 0.12 +/- 0.02 L (P = .55) in patients after regadenoson and placebo, respectively, and new-onset wheezing was observed in 6% and 12%, respectively (P = .33). No patient required acute treatment with bronchodilators or oxygen.

CONCLUSIONS

This pilot study showed the overall safety of regadenoson in 49 compromised outpatients with clinically stable moderate and severe chronic obstructive pulmonary disease.

Side effect profile and tolerability of adenosine myocardial perfusion scintigraphy in patients with mild asthma or chronic obstructive pulmonary disease

BACKGROUND

Adenosine may cause bronchoconstriction in subjects with asthma or chronic obstructive pulmonary disease (COPD). Recent evidence suggests that this effect may be dependent on the severity of disease. This study investigates the tolerability of adenosine stress in patients with mild asthma or COPD undergoing myocardial perfusion scintigraphy.

METHODS AND RESULTS

In this case-control study patients with known or suspected mild asthma or COPD were pretreated with an inhaled beta(2)-adrenergic agonist and adenosine titrated up to the maximal dose of 140 microg x kg(-1) x min(-1) over a period of 6 minutes. The occurrence of side effects and test tolerability were compared between the airway disease group and 72 control subjects. Of 1261 patients, 124 had known or suspected airway disease; of these, 72 (58%) were suitable for adenosine stress. The proportion of tests completed as per protocol in the asthma/COPD group was similar to that of control subjects (93% vs 100%, P = .06). Dyspnea (n = 38 [53%] in asthma/COPD group vs n = 25 [35%] in control group, P = .03) and chest pain (n = 14 [19%] in asthma/COPD group vs n = 16 [22%] in control group, P = .7) were the most common side effects, and these were mostly mild and well tolerated. Bronchospasm occurred in 5 patients with asthma/COPD but reverted shortly after discontinuation of the adenosine infusion. Aminophylline was not required in any case.

CONCLUSIONS

A stepwise 6-minute adenosine infusion with prophylactic beta(2)-adrenergic agonist is safe and well tolerated in patients with mild asthma or COPD.