Letter by Poullis Regarding Article, “Visceral Arterial Compromise During Intra-Aortic Balloon Counterpulsation Therapy”
To the Editor:
Rastan et al1 provide valuable insight into the possible implications of the intra-aortic balloon pump position; however, they fail to address a number of key issues.
First, they assume that the tip of the balloon should be just distal to the left subclavian artery. Although this is standard teaching, positioning the balloon halfway around a corner in an early take off subclavian vessel may potentially result in intimal damage, because the balloon straightens out as it expands, impacting the walls of the curved distal arch. This is clearly demonstrated in Figure 4. The distance should, in fact, be from the start of the descending aorta to the tip of the balloon, showing that the balloon was in fact in the correct position in the figure. The position of the balloon can be reliably deduced from either plain x-ray or transesophageal echocardiography.
Second, the authors correctly refer to the ability of transesophageal echocardiography to identify correct proximal positioning, but they fail to mention its role in distal identification of celiac trunk overlap. Transesophageal echocardiography is able to clearly identify the celiac trunk2 in a large number of patients. Transabdominal ultrasound is less reliable.
Third, because the intra-aortic balloon pump is only inflated in diastole, the effect on visceral perfusion may not be detrimental, and in fact may be beneficial. Oscillation of the balloon within the lumen of the aorta further complicates interpretation, meaning that transesophageal echocardiography is better than computer tomography at assuming this complication, especially with the use of Doppler flow. The beneficial effect of intra-aortic balloon pump on blood pressure, cardiac output, and visceral perfusion is difficult to quantify.
Fourth, application of the Virchow law implies that mesenteric flow and blood hypercoagulability may be important factors determining mesenteric perfusion; however, Rastan et al make no mention of inotropic support, cardiac index, and clotting factor utilization. Quantifying intra- and post-operative hypotension is difficult.
The visceral ischemia documented may be secondary to a low cardiac index, which necessitated the intra-aortic balloon pump insertion, in combination with a low cardiac index, high inotropic support, and clotting factor administration.
We congratulate Rastan et al for their documentation of the frequent occurrence of patient balloon mismatch with regard to length, but we believe that further investigation is needed before deducing that the intra-aortic balloon pump should be made shorter to fit patients.
Michael Poullis, BSc(Hons), MBBS, MD, MIEEE, FRCS(CTh)
Liverpool Heart and Chest Hospital
- © 2011 American Heart Association, Inc.
- Rastan AJ,
- Tillmann E,
- Subramanian S,
- Lehmkuhl L,
- Funkat AK,
- Leontyev S,
- Doenst T,
- Walther T,
- Gutberlet M,
- Mohr FW
- Evangelista A,
- Avegliano G,
- Aguilar R,
- Cuellar H,
- Igual A,
- González-Alujas T,
- Rodríguez-Palomares J,
- Mahia P,
- García-Dorado D