Does Extracorporeal Shock Wave Lithotripsy Cause Changes In Cardiac Isoenzymes?

Abstract

Occasionally during extracorporeal shock wave lithotripsy (ESWL) treatment, or in the immediate post-treatment period, a person will experience cardiovascular instability which may be manifested as anginal symptoms, as changes in cardiac rate or rhythm, or as altered blood pressure. In order to rule out myocardial ischemia, it is prudent to measure cardiac isoenzymes, creatine phosphokinase (CPK), and lactic dehydrogenase (LDH), in addition to whatever else is deemed appropriate by the clinical setting. With a borderline elevation of the CPK, MB bands or a change in the ratio of LD₁ to LD₂, the physician is faced with disturbing questions, “Is this change due to myocardial ischemia, or is the heart in the blast path of the shock wave and thus subject to injury?” In order to answer these questions, we evaluated patients at risk for coronary artery disease with calculi in the left upper pole and/or left renal pelvis, since F₂ for these patients is closest to the heart. We measured CPK and LDH with isoenzymes and electrocardiograms pre- and post-treatment. Our results in 12 patients show that while there is a significant increase in total CPK, the MB fraction is not significantly changed, nor is there a change in the ratio of LD₁ to LD₂. Our early results indicate that there is no damage to myocardium incurred by the shock wave and no release of cardiac isoenzymes. Therefore, when faced with a patient with changes in cardiac isoenzymes in the face of cardiovascular instability, this should be viewed as evidence of myocardial ischemia, and the patient should be treated accordingly.