A head-to-head comparison of infusion and bolus doses of adenosine for stress myocardial contrast echocardiography

Real-time myocardial contrast stress echocardiography using bolus application

In myocardial contrast echocardiography (MCE), power modulation technique may quantify myocardial perfusion in real-time. However, constant infusion of the contrast agent (CA) complicates handling. This pilot study sought for the clinical feasibility of quantitative MCE by a CA bolus application during Adenosine stress echocardiography to diagnose coronary artery disease (CAD). Twenty-four consecutive patients (pts) with contemporary coronary angiography underwent rest and maximum Adenosine stress. Signal intensity could be calculated in 316/348 left ventricular (LV) segments (91%) (18-segment model). At rest, gamma-variate (alpha) as well as saturation function (beta) was not significantly different in healthy men (n = 268) as well as CAD pts (n = 48) (alpha: 0.34 s(-1) versus 0.40 s(-1), n.s.; beta: 0.31 s(-1) versus 0.35 s(-1), n.s.). During Adenosine infusion both values increased in healthy men (alpha: 0.34 +/- 0.37 s(-1) versus 0.44 +/- 0.45 s(-1), p < 0.05; beta: 0.31 +/- 0.33 s(-1) versus 0.40 +/- 0.40 s(-1), p < 0.01), but not in CAD (alpha: 0.40 +/- 0.35 s(-1) versus 0.29 +/- 0.29 s(-1), n.s.; beta: 0.35 +/- 0.32 s(-1) versus 0.27 +/- 0.30 s(-1), n.s.). Sensitivity of alpha/beta reserve <or=1 was 65%/67% (specificity 66%/67%) and improved to 88% in both if also wall motion analysis was considered (specificity 59%/65%). A very high negative predictive value of 96%/97% favours the method for excluding CAD. Bolus administration of CA is feasible in quantitative real-time MCE. However, additional consideration of wall motion analysis is required for reasonable sensitivity. Very high negative predictive values favour the potential of the method in excluding the diagnosis. Further need of research work may be encouraged by those findings.

Intravenous ATP infusions can be safely administered in the home setting: a study in pre-terminal cancer patients

The aim of the study was to investigate the safety of adenosine 5′-triphosphate (ATP) administration at home in pre-terminal cancer patients. Included were patients with cancer for whom medical treatment options were restricted to supportive care, who had a life expectancy of less than 6 months, a World Health Organization performance status 1 or 2, and suffered from at least one of the following complaints: fatigue, anorexia or weight loss >5% over the previous 6 months. Side effects were registered systematically on a standard form according to the National Cancer Institute (NCI) Common Toxicity Criteria. Fifty-one patients received a total of 266 intravenous ATP infusions. Of these, 11 infusions (4%) were given at the lowest dose of 20 μg kg⁻¹ min⁻¹, 85 infusions (32%) at 25–40 μg kg⁻¹ min⁻¹, and 170 (64%) at the highest dose of 45–50 μg kg⁻¹ min⁻¹ ATP. The majority of ATP infusions (63%) were without side effects. Dyspnea was the most common side effect (14% of infusions), followed by chest discomfort (12%) and the urge to take a deep breath (11%). No symptoms of cardiac ischemia occurred in any of the infusions. All side effects were transient and resolved within minutes after lowering the ATP infusion rate. Side effects were most frequent in the presence of cardiac disorders. We conclude that ATP at a maximum dose of 50 μg kg⁻¹ min⁻¹ can be safely administered in the home setting in patients with pre-terminal cancer.