Intra-aortic balloon pump for oesophageal dilatation.

We read with interest the article by Loubani et al. [1] regarding the use of intra-aortic balloon pumps (IABP) for dilating oesophageal strictures. There are fundamental reasons why IABP is not the instrument of choice for oesophageal dilatation, even in difficult cases. IABP was never designed as a dilator. Its function is to produce diastolic augmentation of coronary and systemic blood flow by using the principle of diastolic counterpulsation. The balloon in the IABP is not calibrated to produce a given diameter for a known pressure; therefore the effect of inflating the IABP on a stricture is unknown. The user of an IABP in this situation does not know what diameter he/she is dilating to. We appreciate that inflation pressure is started in these case reports at a low value. The authors do not quote either a maximum inflation pressure or a maximum inflation diameter. The authors mention a pressure-limiter within the system, which they call a ‘feedback mechanism’. In fact the operator has no feedback about the resistance encountered by the balloon other than an alarm which sounds when a (randomly) set pressure has been reached. There has been no mention of any pressure in the article but the mean pressure to rupture the normal oesophagus is approximately 258 mmHg [2]. The pressure required to dilate peptic strictures vary enormously between 25 and 830 mmHg [3], so how does the operator know what to set as maximum? The IABP catheter is at least four times the cost of a conventional balloon dilator, without considering the cost or availability of the pumping system. The IABP is too large to be passed through a fiberoptic endoscope channel, so the authors have used rigid oesophagoscopy in these patients with the higher risk of perforation which this carries [4]. The use of IABP for oesophageal dilatation is not covered by the manufacturer’s warranty. The mechanism behind oesophageal stricture dilatation is to apply a sufficient force to split the encasing fibrotic tissue in the submucosa and muscularis, allowing expansion of the oesophageal lumen, while maintaining mucosal integrity [5]. In contrast to the IABP, oesophageal balloon dilators such as controlled radial expansion (CRE) balloon (Microvasive Boston Scientific Coorporation) have been designed for the purpose of applying a controlled radial disrupting force. Importantly, the operator knows exactly what diameter the balloon has reached for a given applied pressure so that dilatation can stop when a sufficient size lumen has been reached. The CRE balloon can be deployed through a 2.8 mm working channel of a conventional fibreoptic endoscope, avoiding the need for both general anaesthesia and rigid oesophagoscopy, lowering the potential for iatrogenic perforation. The cost is much less than an IABP, and an inexpensive handheld pressure gun is the only pressure generator needed. This system gives the operator true ‘feedback’ as he/she can move the balloon within the stricture at gradually increasing diameters and assess the tightness of grip before dilating further. We do not believe the use of IABP is warranted in treating oesophageal strictures.