EditorWe read with interest the review article entitled Potential value of adenosine 5-triphosphate (ATP) and adenosine in anaesthesia and intensive care medicine'.1 For completeness, we suggest an additional use of adenosine in anaesthesia and surgery.
The authors mentioned its use for supraventricular tachycardia, and for the diagnosis of broad and narrow complex tachycardia at doses of up to 15 mg. Our experience with adenosine is with much larger doses, up to 36 mg i.v. (0.250.5 mg kg1 for thoracic endovascular stent graft placement). This causes transient cardiac asystole for 1520 s.
Although not approved by the Food and Drug Administration for the purpose of inducing cardiac arrest, several articles in the literature support its use in vascular surgery.2 4 In particular, during stent-grafts for thoracic aortic aneurysm (TAA), dissections and transections, in which temporary asystole is used to prevent downward migration of the device during systole. Precision in stent deployment is essential and requires, usually, <20 s of reduced afterload.4
Our experience with endovascular stent surgery encompasses an 11 yr period, both with abdominal and thoracic aortic aneurysms and a recent published study of 100 patients over 3 yr undergoing TAA surgery by the stent method.5 Of these 100 patients, 22 received adenosine boluses of 1836 mg for the purpose of inducing transient cardiac arrest.
While the authors1 mentioned its potential use for blood pressure reduction by i.v. infusion (50350 µg kg1 min1), we, however, acutely reduce arterial pressure by an i.v. bolus. A dramatic decrease in arterial pressure by an i.v. bolus is related to a reduction or brief cessation in heart rate and contractility. This is in contrast to what the authors quoted that 40 mg ATP induced a moderate decrease in arterial pressure without a change in heart rate.
We agree with Skrabanja and colleagues that the haemodynamic effects of adenosine are brief and transient, owing to its rapid metabolism. Since adenosine's action is at the purinergic receptors, drugs that interfere with nucleotide metabolism such as dipyridamole, can markedly enhance its effect. Thus, even usual doses of 612 mg can induce asystole. On the other hand, competitive antagonists of adenosine (i.e. methylxanthones, such as caffeine, theophylline, and amrinone) may demonstrate resistance to its effects and an increased dose may be required.
Finally, patients presenting with TAA frequently have co-morbidities in which adenosine should be used only with caution. Obstructive lung disease not associated with bronchoconstriction does not preclude its use. However, in patients with a history of reactive airways its use should be avoided. We also avoid its use in patients with intrinsic AV nodal block or pharmacologic AV nodal slowing with drugs such as digoxin or calcium channel blockers.
Torrance, CA, USA
EditorWe thank Dr Kazaku and Dr Lippmann for their additional comments. Although we have no personal experience, we believe that adenosine indeed can be a valuable tool in achieving optimal surgical conditions in TAA patients.6 In modern anaesthesia we frequently use the adverse effects of a drug in a specific situation to achieve an effect that would be detrimental in normal clinical practice, for example cardiac arrest.7
If clinically indicated the use of adenosine in patients with intrinsic or pharmacological AV nodal block temporary ventricular pacing could be considered. In patients with asthma, bronchoconstrictive or bronchospasmic disease adenosine remains contraindicated, as adenosine selectively interacts with activated mast cells, with subsequent release of other mediators.8
Maastricht, The Netherlands
References
1 Skrabanja ATP, Bouman EAC, Dagnelie PC. Potential value of adenosine 5'-triphosphate (ATP) and adenosine in anaesthesia and intensive care medicine. Br J Anaesth 2005; 94: 55662
2 Hashimoto T, Young WL, Aagaard B, Joshi S, et al. Adenosine-induced ventricular asystole to induce transient profound systemic hypotension in patients undergoing endovascular therapy. Anesthesiology 2000; 93: 9981001[CrossRef][ISI][Medline]
3 Schwarte L, Hartmann M. Intentional circulatory arrest to facilitate surgical repair of a massively bleeding artery. Anesth Analg 2003; 97: 33940
4 Dorros G, Cohn JM. Adenosine-induced transient cardiac asystole enhances precise deployment of stent-grafts in the thoracic or abdominal aorta. J Endovasc Surg 1996; 3: 2702[CrossRef][ISI][Medline]
5 Kakazu CZ, Lippmann M, Hanson T, Lee J, White RA. Thoracic aortic aneurysm repair in the awake elderly patient: a prospective study on an alternative anesthetic technique. Anesth Analg 2005; 100: S-80
6 Kahn RA, Moskowitz DM, Marin ML, et al. Safety and efficacy of high-dose adenosine-induced asystole during endovascular AAA repair. J Endovasc Therapy 2000; 7: 2926[CrossRef][ISI][Medline]
7 Rankin AC, Oldroyd KG, Chong E et al. Value and limitations of adenosine in the diagnosis and treatment of narrow and broad complex tachycardias. Br Heart J 1989; 62: 195203[Abstract]
8 Pelleg A, Schulman ES. Adenosine 5'-triphosphate axis in obstructive airway diseases. Am J Ther 2002; 9: 45464[CrossRef][Medline]