Intravenous adenosine: Continuous infusion and low dose bolus administration for determination of coronary vasodilator reserve in patients with and without coronary artery disease

Abstract

To assess the use of adenosine as an alternative agent for determination of coronary vasodilator reserve, hemodynamics and coronary blood flow velocity were measured at rest and during peak hyperemic responses to continuous intravenous adenosine infusion (50, 100 and 150 micrograms/kg per min for 3 min) and intracoronary papaverine (10 mg) in 34 patients (17 without [group 1] and 17 with [group 2] significant left coronary artery disease), and in 17 patients (11 without and 6 with left coronary artery disease) after low dose (2.5 mg) intravenous bolus injection of adenosine. The maximal adenosine dose did not change mean arterial pressure (-10 +/- 14% and -6 +/- 12% for groups 1 and 2, respectively) but increased the heart rate (15 +/- 18% and 13 +/- 16, respectively). For continuous adenosine infusions, mean coronary flow velocity increased 64 +/- 104%, 122 +/- 94% and 198 +/- 59% and 15 +/- 51%, 110 +/- 95% and 109 +/- 86% in groups 1 and 2, respectively for each of the three doses. Mean coronary flow velocity increased significantly after 100 and 150 micrograms/kg of adenosine and 10 mg of intracoronary papaverine (48 +/- 25, 52 +/- 19 and 54 +/- 21 cm/s, respectively; all p less than 0.05 vs. baseline) and was significantly higher than in group 2 (37 +/- 24, 32 +/- 16, 41 +/- 23 cm/s; all p less than 0.05 vs. group 1). The coronary vasodilator reserve ratio (calculated as the ratio of hyperemic to basal mean flow velocity) for adenosine and papaverine was 2.94 +/- 1.50 and 2.94 +/- 1.00, respectively, in group 1 and was significantly and similarly reduced in group 2 (2.16 +/- 0.81 and 2.38 +/- 0.78, respectively; both p less than 0.05 vs. group 1). Low dose bolus injection of adenosine increased mean velocity equivalently to that after continuous infusion of 100 micrograms/kg, but less than after papaverine. There was a strong correlation between adenosine infusion and papaverine for both mean coronary flow velocity and coronary vasodilator reserve ratio (r2 = 0.871 and 0.325; SEE = 0.068 and 0.189, respectively; both p less than 0.0005). No patient had significant arrhythmias or prolongation of the corrected QT (QTc) interval with adenosine, but papaverine increased the QT (QTc) interval from 445 +/- 44 to 501 +/- 43 ms (p less than 0.001 vs. both maximal adenosine and baseline) and produced nonsustained ventricular tachycardia in one patient.(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac purinergic signalling in health and disease

“…Continuous infusion and low-dose bolus injection of adenosine were early approaches to determine coronary vasodilator reserve in patients with CAD [770]. The safety of adenosine infusion during cardiac MRI was confirmed [771].…”

Hyaluronidase treatment of coronary glycocalyx increases reactive hyperemia but not adenosine hyperemia in dog hearts

“…This glycocalyx insensitivity should be taken into account when using adenosine-induced coronary hyperemia as a marker for vasodilating capacity to an ischemic stimulus. coronary circulation; hyaluronidase; dogs TO ASSESS the functional severity of coronary stenoses in the clinic, use of adenosine for inducing maximal coronary hyperemia in patients has been well established (8,10,17,34). Clinical decision-making to intervene is based on intracoronary parameters that are derived during hyperemia, and it is therefore critical that the adenosine-induced hyperemia accurately reflects the coronary hyperemia that can be attained by endogenous stimuli (7).…”

The imbalance between coronary reserve and wall stress explains the severity of ventricular dysfunction in hypertension

“…36 Also, continuous intravenous adenosine appears not to be associated with a substantial flow-mediated increase in the luminal diameter of epicardial coronary arteries. 37 Apart from not controlling for coronary epicardial diameter, the assessment of coronary dynamics by transesophageal Doppler echocardiography precludes the examination of endothelial function in the coronary bed, for which intracoronary studies are required. It is conceivable that a number of patients with normal responses to adenosine might have impaired responses to acetylcholine.…”