How is Impella CP with SmartAssist different from Impella CP?

October 28, 2019

Technical advancements with Impella CP SmartAssist compared to Impella CP to improve ease-of use and patient management include1:

  • Faster, Simplified Impella CP Console Set-up of time of less than 90 seconds
  • New optical placement sensor allows for precise positioning of the pump in the aorta and left ventricle and repositioning in the ICU often without the need for catheterization lab or ultrasound imaging
  • Simplified patient management with real-time displays of critical hemodynamic metrics including left ventricular end-diastolic pressure (LVEDP), mean arterial pressure (MAP), and cardiac power output (CPO) directly on the Impella console.

The ability to track relative change in hemodynamic metrics over time to assist in weaning and escalation of therapy

2. How is Impella CP with SmartAssist the same as Impella CP?

Both Impella CP and Impella CP with Smart Assist are an axial flow transaortic cardiac support device mounted to on a 9 Fr catheter with a 14 Fr pump cannula that provides hemodynamic support with sustained peak flows of up to 4.3 L/minute.

3. What can the hemodynamic metrics on the Impella console be used for?

The hemodynamic metrics displayed on the Impella console such as left ventricular end-diastolic pressure (LVEDP), mean arterial pressure (MAP), and cardiac power output (CPO) provide critical information that aids in clinical decision-making. These hemodynamic metrics are useful for monitoring changes in Impella pump performance and patient status, especially during weaning and escalation of therapy.

In addition, these metrics allow the user to spot an issue early (e.g.: a drop in estimated left ventricular pressure due to suction), identify the likely root cause, and confirm resolution easily and quickly (e.g.: confirm with relative change in LVEDP).

4. What is left ventricular end-diastolic pressure (LVEDP)?

Left ventricular end-diastolic pressure (LVEDP) refers to the pressure in the left ventricle (LV) at the end of diastolic filling and immediately before ventricular contraction.2 The normal value for LVEDP is < 12 mmHg and is elevated in patients with acute and chronic LV failure. Thus, relative changes in LVEDP provide a useful measurement to monitor the changing clinical status of a patient.

5. How is LVEDP calculated using Impella CP SmartAssist?

The LVEDP is calculated using the pressure assessed in the aorta from the optical sensor and the pressure derived from the differential sensor from the motor. The Impella CP SmartAssist is designed to run at a constant motor speed in response to the real-time changes in pressures in the aorta and left ventricle. The Impella system varies the amount of current supplied to the motor to maintain a constant motor speed and that variation correlates with the differential pressure (AoP – LVP) across the pump. The reliable measurement of motor current and aortic pressure provides continuous, real-time, and precise determination of the LVEDP.

6. What is cardiac power output (CPO)?

Cardiac power output (CPO) is the product of mean arterial pressure (MAP) and cardiac output (CO), CPO = MAP x CO/451, measured in watts (W) and is a measure of tissue perfusion.3 The pumping ability of the heart can be determined using CPO, an objective measure incorporating metrics of both pressure and flow. The CPO of a normal adult with CO of 5 L/min and MAP of 90 mm Hg is 1 W.3 Klasnja et al. showed that CPO increased to up to 6 W in response to exercise in athletes.4 Likewise, since most of the cardiac pumping potential is harnessed during acute heart failure, measurement of CPO serves as an indicator of severity of acute heart failure and changes in CPO serves as a useful prognostic indicator.3,5

Analysis of patients enrolled in the SHOCK trial registry demonstrated that a CPO of 0.53W to be the strongest predictor of in-hospital mortality. A recent report based on the National Cardiogenic Shock Initiative (NCSI) suggested that CPO measurements along with lactate levels at 12-24 hours post-Impella implantation predicted the overall outcomes and helped guide clinical decisions such as escalation of support early in the course of the disease.6

7. How is CPO calculated using Impella CP SmartAssist?

CPO is the combination of two measurements: cardiac output (CO) and the mean aortic pressure (MAP). The CO is entered from a reference device such as a Swan-Ganz catheter and the MAP is measured based on the location of the fiber-optic sensor on the Impella heart pump within the aorta.7 It is recommended to enter a new CO from a reference device every 8 hours during Impella support.

8. What are the hemodynamic metrics displayed on the Impella controller used for?

The LVEDP screen on the Impella console displays time trends for MAP, LVEDP, and Impella flow. These trends provide information regarding the functioning of the Impella pump and the change in the hemodynamic status of the patient. However, these trends are to be used for informational purposes only and not as diagnostics7.

References:

  1. Abiomed Press Releases. Impella SmartAssist Platform Launches at SCAI, Designed to Further Improve Patient Outcomes. http://investors.abiomed.com/news-releases/news-release-details/impella-smartassist-platform-launches-scai-designed-further. Accessed August 8, 2019.
  2. Chang BY, Keller SP, Bhavsar SS et al. Mechanical circulatory support device-heart hysteretic interaction can predict left ventricular end diastolic pressure. Sci Transl Med. 2018; 10(430): eaao2980.
  3. Fincke R, Hochman JS, Lowe AM, et al. Cardiac power is the strongest hemodynamic correlate of mortality in cardiogenic shock: a report from the SHOCK trial registry. J Am Coll Cardiol. 2004;44(2):340-348.
  4. Klasnja AV, Jakovljevic DG, Barak OF, Popadic Gacesa JZ, Lukac DD, Grujic NG. Cardiac power output and its response to exercise in athletes and non-athletes. Clin Physiol Funct Imaging. 2013;33(3):201-205.
  5. Cotter G, Williams SG, Vered Z, Tan LB. Role of cardiac power in heart failure. Curr Opin Cardiol. 2003;18(3):215-222.
  6. Basir MB, Kapur NK, Patel K, et al. Improved Outcomes Associated with the use of Shock Protocols: Updates from the National Cardiogenic Shock Initiative. Catheter Cardiovasc Interv. 2019;93(7):1173-1183.
  7. Abiomed Product Manual for Impella CP with SmartAssist. June 2019.

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