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Preconditioning of human myocardium with adenosine during coronary angioplasty
M A Leesar1, M Stoddard, M Ahmed
1Division of Cardiology, University of Louisville, Ky 40292, USA.
Insights
Adenosine infusion before percutaneous coronary angioplasty (PTCA) effectively preconditions human heart muscle against ischemia. This adenosine preconditioning offers superior protection compared to traditional ischemic preconditioning during PTCA procedures.
Area of Science:
- Cardiology
- Pharmacology
Background:
- The potential of adenosine to precondition human myocardium against ischemia in vivo remains unestablished.
- Ischemic preconditioning is a known phenomenon that protects the heart muscle from damage during brief periods of reduced blood flow.
Purpose of the Study:
- To investigate whether intracoronary adenosine infusion can precondition human myocardium against ischemia during percutaneous transluminal coronary angioplasty (PTCA).
Main Methods:
- Thirty patients undergoing PTCA were randomized to receive either an intracoronary infusion of adenosine or normal saline.
- Following the infusion, patients underwent three sequential balloon inflations to induce ischemia.
- Intracoronary ECG and chest pain scores were used to assess the degree of ischemia, while echocardiography evaluated regional wall motion.
Main Results:
- Adenosine-treated patients showed significantly smaller ST-segment shifts compared to controls during all balloon inflations.
- Adenosine preconditioning provided greater protection than ischemic preconditioning observed in control patients.
- Chest pain scores mirrored the ST-segment shift findings, indicating reduced ischemic discomfort with adenosine.
- Adenosine did not adversely affect baseline regional wall motion or cause major adverse effects.
Conclusions:
- Adenosine effectively preconditions human myocardium against ischemia in vivo.
- Adenosine pretreatment is a highly effective prophylactic strategy, surpassing ischemic preconditioning in protecting against ischemia during PTCA.
- Further research is needed to establish the safety of adenosine infusion in specific coronary arteries, particularly the right and circumflex, when a temporary pacemaker is in use.
Background:
It is unknown whether adenosine can precondition human myocardium against ischemia in vivo.
Methods And Results:
Thirty patients were randomized to receive a 10-minute intracoronary infusion of adenosine (2 mg/min) or normal saline; 10 minutes later, they underwent percutaneous transluminal coronary angioplasty (PTCA; three 2-minute balloon inflations 5 minutes apart). In control patients, the ST-segment shift on the intracoronary ECG was significantly greater during the first inflation than during the second and third inflations, consistent with ischemic preconditioning. In contrast, in adenosine-treated patients, there were no differences in ST-segment shift during the three inflations. The ST-segment shift was significantly smaller in the adenosine-treated group compared with the control group during all three inflations. The reduction in ST-segment shift afforded by adenosine during the first inflation (-72% versus first inflation in control subjects) was greater than that afforded by ischemic preconditioning in control subjects (-52% during the third versus first inflation). Measurements of chest pain score paralleled those of ST-segment shift. Adenosine had no effect on baseline regional wall motion as determined by quantitative two-dimensional echocardiography. Thus, intracoronary infusion of adenosine before PTCA rendered the myocardium remarkably resistant to subsequent ischemia. Judging from the intracoronary ECG, the protection provided by adenosine was even superior to that provided in control subjects by the ischemia associated with the first two balloon inflations. Infusion of adenosine had no major adverse effects in patients undergoing PTCA of the left anterior descending or circumflex arteries.
Conclusions:
Adenosine preconditions human myocardium against ischemia in vivo. Pretreatment with adenosine is remarkably effective (even more effective than ischemic preconditioning) and could be used prophylactically to attenuate ischemia in selected patients undergoing PTCA of the left anterior descending coronary artery. Whether adenosine can be safely infused into the right or the circumflex coronary artery in the presence of a temporary pacemaker remains to be established.