Pneumatosis Intestinalis, a Dreaded Complication of Intra-Aortic Balloon Pump Use

Dear Editor:

In current international guidelines, intra-aortic balloon pump (IABP) use is recommended in cardiogenic shock complicating acute myocardial infarction on the basis of registry data. Although IABP did not reduce 12-month all-cause mortality in patients undergoing early revascularization for myocardial infarction complicated by cardiogenic shock,¹ it is still used in patients with multivessel disease, low ejection fraction, and hemodynamic stability prior coronary artery bypass surgery (CABG). We had a patient who required IABP support and later developed a grim complication of pneumatosis intestinalis despite smaller-size IABP use. We think this complication should be taken into consideration in females with small size and diseased aortas.

Case Presentation. A 56-year-old white female with a past medical history of hypertension presented to the local ER with sudden onset shortness of breath, chest pain, and diaphoresis. The patient had a pulseless electrical activity (PEA) cardiac arrest on arrival to the emergency room and was successfully revived with cardiopulmonary resuscitation (CPR) within 10 minutes. Electrocardiogram (ECG) done after successful CPR showed anterolateral ischemia but no ST elevation and troponin was 1.7 ng/mL. She was started on low-dose intravenous (IV) norepinephrine and was transferred to our hospital’s intensive care unit for further management of mechanical ventilation. Chest x-ray revealed right lower-lobe consolidation and leukocyte count was 25,000. Troponin level peaked at 6.43 ng/mL.  Echocardiogram revealed depressed systolic function with an ejection fraction of 35%-40% and regional wall-motion abnormality suggestive of ischemic heart disease. She was weaned off norepinephrine and extubated after 48 hours of presentation and continued on heparin, aspirin, metoprolol, rosuvastatin, and IV levofloxacin. The third day, she had another PEA cardiac arrest, which responded to CPR with spontaneous return of circulation within 5 minutes. ECG showed similar changes and she was taken to the cardiac catheterization laboratory emergently. A coronary angiogram was done that showed significant ostial, proximal, and mid long left anterior descending (LAD) artery lesions, significant right coronary artery lesion, and chronic occlusion of the left circumflex artery with elevated left ventricular filling pressure of 35 mm Hg. Cardiothoracic surgery was consulted for coronary artery bypass graft and a 7.5 Fr 30 mL (Arrow); intra-aortic balloon pump (IABP) was placed without difficulty. A 30 mL size was chosen based on the patient’s height of 5 feet 4 inches. Patient’s weight was 55 kg and body surface area (BSA) was 1.6 m². Intravenous heparin was continued. After 2 days, the day she was planned to undergo CABG, the patient developed abdominal distension and later on hypotension requiring IV fluids and IV norepinephrine. Up until that day, she had been tolerating tube feeds well. Lactate that had previously been normal was noted to be elevated to 10.4 mmol/L. Abdominal radiogram showed radiolucent sign of air between intestinal contents and colonic wall suggestive of pneumatosis intestinalis (Figure 1). CT scan of the abdomen without IV contrast confirmed the findings with pneumatosis of ascending colon and distal small bowel, ileocolic venous gas, small-bowel dilatation, and ascites. There was also calcium note in the abdominal aorta on the CT scan. The outer aortic wall was measured at 1.8 x 2 cm axially at the level of superior mesenteric artery, which was also calcified. The patient underwent and exploratory laparotomy followed by extensive resection of necrotic bowel including the distal jejunum, the entire ileum, and the right and proximal two-thirds of the transverse colon. However, the patient did not recover from shock after surgery and care was withdrawn as per wishes of family in accordance with the patient’s will. Surgical pathology confirmed pneumatosis of small bowel, colon, and appendix (Figure 2).

Discussion. Pneumatosis intestinalis is a radiological sign characterized by presence of gas in the wall of the gastrointestinal tract. It is an uncommon finding that can be benign in etiology, but could be a manifestation of a severe problem, ie, necrotizing enterocolitis from bowel ischemia. While limb ischemia, a well-known complication of IABP and most common reason of premature IABP discontinuation is easy to identify, visceral ischemia can be difficult to recognize. In a study by Rastan et al of 63 patients who had IABP and a CT scan, visceral artery compromise was seen in a staggering 61 patients (96.8%).² Ferguson et al reported female sex, peripheral artery disease, BSA <1.65 m², and age >75 years as independent predictors of major complications with IABP use.³ In a study by Sirbu et al, 59% of patients who developed ischemic vascular complications with IABP use had fatal outcomes.⁴ Anatomic landmarks on plain chest radiography have been established to define correct proximal IABP position, and standard balloon lengths have been developed to avoid coverage of the visceral arteries during balloon inflation. The most commonly used balloon pumps are 40 cc balloon, with balloon length of 258 mm (Datascope) or 260 mm (Arrow) and diameter of 15 mm. Anatomic and device length mismatch is common as reported by Rastan et al. In their study, up to 87.3% superior mesenteric artery and 66.6% of renal arteries were compromised with IABP use.² Perhaps better tailoring of balloon pumps with availability of balloon pumps in various sizes can be a solution to this problem of “one size fits all.” It has also been suggested that balloon pump placement should be avoided in the setting of a heavily calcified aorta.² A small aortic caliber also increases complication rates. The mean ascending and descending thoracic aortic diameters for females are 31.4 ± 3.2 mm and 22.6 ± 2.2 mm, respectively and for males are 33.5 ± 3.6 mm and 25.1 ± 2.5 mm, respectively.⁵ However, we don’t know the exact diameter at which routine sizes of IABP should be avoided. Most balloons come in sizes of 25 cc, 30 cc, 34 cc, 40 cc, and 50 cc with a catheter diameter of 7 Fr, 7.5 Fr, or 8 Fr, and smaller balloons are available for pediatric use. The diameter of the balloon, when fully expanded, ideally should not exceed 80%-90% of the diameter of the patient’s descending thoracic aorta. There is only one prior report of pneumatosis intestinalis in the setting of IABP use in an 83-year-old female after acute myocardial infarction that also had a fatal outcome. Obviously, the smaller-size descending aorta in females may predispose increased complications with IABP. We should also mention that most patients who get a balloon pump are severely ill and in shock. They are predisposed to visceral ischemia due to episodes of hypotension, poor perfusion in general, and etiology of visceral ischemia could be multifactorial.

Conclusion. Our case shows visceral compromise with IABP use in a female patient with a small-caliber aorta. Prolonged IABP support (especially with larger balloons) should be avoided in patients with diseased, narrow-caliber aorta, and when there is anatomic length mismatch. Since visceral ischemia can be difficult to recognize, patients who require prolonged IABP support should be monitored with daily abdominal exams and abdominal x-rays.

References

1. Thiele H, Zeymer U, Neumann FJ, et al; on behalf of the intra-aortic balloon Pump in cardiogenic shock II (IABP-SHOCK II) trial investigators. Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): final 12 month results of a randomized, open-label trial. Lancet. 2013;382(9905):1638-1645. Epub 2013 Sep 3.
2. Rastan AJ, Tillmann E, Subramanian S, et al. Visceral arterial compromise during intra-aortic balloon counterpulsation therapy. Circulation. 2010;122(11 Suppl):S92-S99.
3. Ferguson JJ 3rd, Cohen M, Freedman RJ Jr, et al. The current practice of intra-aortic balloon counterpulsation: results from the Benchmark Registry. J Am Coll Cardiol. 2001;38(5):1456-1462.
4. Sirbu H, Busch T, Aleksic I, Friedrich M, Dalichau H. Ischaemic complications with intra-aortic balloon counter-pulsation: incidence and management. Cardiovasc Surg. 2000;8(1):66-71.
5. Wolak A, Gransar H, Thomson LE, et al. Aortic size assessment by noncontrast cardiac computed tomography: normal limits by age, gender, and body surface area. JACC Cardiovasc Imaging. 2008;1(2):200-209.

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From the Louisiana State University Health Sciences Center, Shreveport, Louisiana.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Address for correspondence: Assistant Prof Nuri I. Akkus, MD, LSU Health Sciences Center, Shreveport Cardiology, 1501 Kings Highway, Shreveport, LA 71111. Email: iakkus@hotmail.com