Archived case 182 · August 11-August 18, 2015
Critically ill patient in the intensive care unit
Identify the device annotated by the white arrows? What is it? What is its purpose” Is this device appropriately positioned?
Radiologic Findings: Single edge-enhanced AP portable chest radiograph shows a normal sized cardiomediastinal silhouette, mild pulmonary edema and bilateral pleural effusions. Mild left lower lobe volume loss is present. The patient is intubated. The endotracheal tube is appropriately positioned. A gastroenteric tubes and dual left internal jugular approach central venous catheters are also present. The annotated device in question represents an Impella® circulatory assist device. The Impella® is well-positioned. Answer Diagnosis: Impella® Circulatory Assist Device
Impella® Circulatory Assist Device
Answer
Diagnosis: Impella® Circulatory Assist Device
Differential Diagnosis
None
Discussion
The Impella® is a short-term ventricular support device manufactured by Abiomed, Inc. (Danvers, Massachusetts, USA) and designed to be used for a short period of time (i.e., several hours to days). There is a percutaneous (LP) and surgical implantable (LD) version available for left ventricular assistance and a surgical implantable version available for right ventricular assistance (RD). The device use for high risk patients is almost exclusively the LP version. The Impella® is currently available in 3 sizes: LP 2.5, CP, or 5.0 with a 12; 14; and 21-French miniature pump that augments cardiac output by 2.5; 4.0; and 5.0 L/min respectively. The device contains a blood inlet area, located proximal to the pigtail, which should be positioned in the mid-left ventricular cavity and an outlet area that should be positioned in the ascending aorta, just beyond the aortic valve. The outlet area contains a pump motor. Blood is drawn from the left ventricular cavity and expelled into the ascending aorta by a miniaturized rotary pump capable of a maximum rotation of 51,000 rpm.
Clinical indication for the Impella® circulatory assist device may include:
• Bridge to recovery after acute myocardial infarction or post-surgery complicated by myocardial stunning
• Bridge to destiny therapy with LVAD or heart transplant
• Pre-operative stabilization for cardiac surgery
• High risk percutaneous cardiac procedures
• Cardiogenic shock
The hemodynamic benefits of the Impella® circulatory assist device may include:
• Maintenance of cardiac output
• Active left ventricular unloading with reduction of left ventricular filling pressure
• Preservation of vital organ perfusion
Complications
PROTECT I Trial on Impella® 2.5 (2009)
· 30 day incidence of major adverse events (acute MI and death): 20%
· No reported aortic valve injury, cardiac perforation, or limb ischemia
PROTECT II Trial on Impella® 2.5 vs. IABP (2012):
30-day incidence of major adverse events is similar with IABP or Impella® 2.5 hemodynamic support (40.1% vs 35.1% respectively)
Mild, transient hemolysis without clinical sequela in 10%
Rate of bleeding and vascular complications are comparable with IABP with novel Impella® CP
Selected Readings
1. Boudoulas KD, Pederzolli A, Saini U, et al. Acute Card Care 2012; 14(4):120–4.
2. Dixon SR. JACC Cardiovasc Interv. 2009; 2(2):91-6.
3. Meyns B, Dens J, Sergeant P, et al. Thorac Cardiovasc Surg 2003; 51(6): 312–7.
O’Neill WW et al. Circulation 2012; 126(14):1717-27.Original case written by its authors at Virginia Commonwealth University and published at this address as part of a weekly teaching collection. Reproduced here as an archive.