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Troubleshooting and treating the balloon that fails to deflate

Equipment entrapment in the coronary tree can occur under a variety of circumstances. Primary manufacturing defects are extremely rare and the vast majority of events usually arise when devices are used beyond the control of the manufacturer. A classic source of misadventures is the heavily calcified artery that either entraps the balloon material or causes the operator to exceed bursting pressures resulting in unexpected outcomes. Applying excessive torque especially if there is anchoring of the distal wire that tethers the device is a set up for wire fracture and similar device misadventure. Failure of a balloon to deflate is a very rare situation. This can occur if either there is kinking or closure of the lumen supplying the fluid for balloon inflation or plugging of the lumen with solid material such as foreign bodies or crystallized contrast. Prevention is clearly preferable. Care in not kinking catheters by rushed catheter insertion and, otherwise, replacement of damaged catheters is preferable to hope that the kink will not be noticed. Absorbent gauze or powder from gloves should not make contact with the contrast mixture used for balloon inflation as these could form a nidus for a plug. When using a large volume balloon, contrast can be further diluted to enhance deflation by lowering the fluid viscosity. Unfortunately, once a balloon fails to deflate, it is too late for prevention and a solution must be found. Girish et al. in this issue [1] describe their approach when prevention failed. Attempts at dilution and flushing the lumen did not resolve the dilemma. Controlled puncture was chosen rather than risking the uncontrolled rupture of the balloon with high-inflation pressure. Uncontrolled rupture can result in further issues with entrapment of deflated balloon material in the vessel wall or vessel wall rupture itself. To protect the vessel proximal to the balloon in this case, the guiding catheter was inserted deep into the coronary artery before advancement of the stiff, back-end of a 0.18-inch wire that successfully perforated the balloon. Another option would have been to advance a second coronary catheter or microsheath through the guiding catheter up to the inflated balloon and used that device to protect the proximal vessel wall from the potential trauma of inadvertent contact with the stiff end of the puncture wire. That approach might have eliminated the risk of guide tip trauma. In any case, a controlled puncture of the end of the balloon then allows removal. Care must be taken to prevent balloon tearing as this may cause further entrapment or failure to be able to fully retrieve the broken balloon through the sheath. Reviewing the US Food and Drug Administrations MAUDE database [2] using ‘‘deflation issue’’ and ‘‘stent coronary’’ as search terms, one can find a multitude of reports. Common to most reports is a lack of information confirming the mode of failure. Most report ‘‘Device Not Returned To Manufacturer.’’ This is unfortunate, as the ultimate cause of failure is never really discovered. Unusual modes of failure due to design faults such as seen at one point with the Boston Scientific device [3] would never have been discovered without mode of failure evaluation. Cardiologists are a curious but impatient group, but they are not engineers. Rather than further destroying the device once removed, devices that fail should be preserved for expert evaluation and not be subjected to the physician or staff’s destructive curiosity. Equipment may malfunction when used beyond its engineered limits and this is avoided by not expecting more than the equipment can deliver. A manufacturing or design error is far more unusual, given the rigor of the medical device industry, but failure of physicians to provide these devices to industry may allow further mishaps to occur before the root cause is discovered.