Does shock wave lithotripsy of renal stones cause cardiac muscle injury? A troponin I-based study

Objectives. To investigate whether shock wave lithotripsy (SWL) causes cardiac muscle injury that alters the levels of troponin I plasma, a cardio-specific enzyme shown to be useful in diagnosing cardiac muscle injury because of its high specificity. Methods. Patients treated by SWL for renal stones participated in the study. They had undergone a baseline 12-lead electrocardiogram (ECG) a few days earlier. One day after SWL, they were queried about any chest discomfort, blood was drawn for evaluation of troponin I and creatine kinase with isoenzymes (CK-MB), and an ECG was carried out. Results. Thirty-two patients (21 men and 11 women, mean age ± SD 51.0 ± 10.6 years) comprised the study group. Fourteen SWL treatments were on the right side and 18 on the left. The mean number of shock waves was 2859 ± 202. The mean time to evaluation after SWL was 22.3 ± 1.3 hours. None of the patients reported chest discomfort. The mean value was 6.6 ± 9.2 mU/mL for CK-MB and 0.02 l ± 0.04 ng/mL for troponin I. No ECG changes suggestive of myocardial injury were evident. None of the 5 patients who experienced ventricular extrasystoles during SWL had any evidence of cardiac muscle injury. Conclusions. We evaluated the symptoms, perioperative ECG changes, and cardiac troponin I and CK-MB plasma levels in patients who underwent SWL for renal stones and did not identify any myocardial damage. Troponin I plasma levels were not elevated after this procedure and, therefore, remain suitable for evaluation of patients complaining of chest pain after SWL.