Contrast Echoes Detected During Percutaneous Mitral Balloon Commissurotomy with Inoue Balloons and Their Relation to Cerebral Microembolic Signals

The aim of this study was to find out the mechanism of genesis of contrast echoes detected with echocardiography during percutaneous mitral balloon commissurotomy (PMBC) procedures with Inoue balloons and to assess their association with cerebral microembolic signals with transcranial Doppler examinations. Ten Inoue balloons (Toray Instruments) were used in 10 patients (mean age 36 ± 10 years). In all patients transesophageal echocardiographies with a multiplane 5 MHz probe were performed immediately before and during the PMBC procedure. None of the patients had left atrial thrombus during the PMBC. All of the balloons were inflated within the left atriums and left ventricles and were tested in saline to see whether there was a visible air leak after the PMBC procedures. Transcranial Doppler examinations were done with 2 MHz probes from the middle cerebral artery. Contrast echoes were detected in all patients during inflation and/or deflation, independent of the intracardiac sites. After a few cardiac cycles there was a very intense shower of microembolic signals detected with the transcranial Doppler examination, which persisted for all inflations and/or deflations. All balloons yielded visible air leaks from the two small holes at the waist of the balloons in saline. There were a few contrast echoes recorded in some of the patients during the exchange of equipment, and one patient had a transient neurologic and coronary ischemic event following the introduction of the stretcher tube of the Inoue balloon. Intracardiac contrast echoes and transcranial microembolic signals during the PMBC procedure were detected in all PMBC procedures and were due to air that was entrapped between the two latex layers of the Inoue balloons and air introduced from outside during the exchange of the equipment.