Escalation Therapy, AMI Cardiogenic Shock, Surgical Applications
Escalation Strategies in Cardiogenic Shock that Increase Unloading and Survival
Mark Anderson, MD, discusses how cardiac surgery may be able to help move the dial closer to the ≥80% survival to discharge quality measure in the National Cardiogenic Shock Initiative (NCSI) Study. Dr. Anderson is chair of the division of cardiothoracic surgery at Hackensack Meridian Health and professor of surgery at Hackensack-Meridian School of Medicine at Seton Hall.
In this presentation, Dr. Anderson describes how the Impella 2.5®, Impella CP®, and Impella 5.0® heart pumps differ in the amount of hemodynamic support and unloading each provides. While Impella 5.0 provides the most support and unloading, Dr. Anderson notes a reluctance on the part of his surgical colleagues to escalate patients to Impella 5.0. Not all surgeons, he explains, are familiar with the axillary artery cut-down, and the 21Fr Impella 5.0 has a relatively long and stiff motor that is sometimes difficult to pass through the axillary artery into the ascending aorta.
The recent approval of the Impella 5.5® with SmartAssist®, Dr. Anderson explains, provides an “exciting new technology to add to the armamentarium of how we’re dealing with these patients with shock.” Dr. Anderson and his team have already completed four Impella 5.5 with SmartAssist cases. With a motor that is about 50% shorter than the Impella 5.0, the 19Fr Impella 5.5 with SmartAssist delivers up to 5.5 liters per minute and can be implanted in a broader range of patients, including smaller patients with smaller axillary arteries.
Regarding escalating support in patients with cardiogenic shock, Dr. Anderson emphatically states, “I do not consider V-A ECMO as legitimate escalation for these patients.” He shows how the PV loops for a patient in shock receiving ECMO show some improvement in aortic pressure, “but you’re seeing a marked increase in left ventricular pressure and an overall loading of the heart,” Anderson explains, “which is really not what we’re after with respect to, certainly, maximizing cardiac recovery.”
When faced with a patient on V-A ECMO with no Impella, or even a patient with V-A ECMO and an Impella CP, Dr. Anderson explains that his strategy is to implant an axillary Impella 5.0, removing the Impella CP if one is in place, and promptly weaning V-A ECMO in either scenario. He emphasizes that V-A ECMO should not be the knee-jerk response to hypoxemia. “To me, the knee-jerk reflex should be increased unloading,” states Anderson, “because we have found, with that increased unloading, we can skip the V-A ECMO step the vast majority of the time.”
Dr. Anderson then investigates which metrics can guide escalation to an Impella 5.0 or Impella 5.5 with SmartAssist. He mentions both number of inotropes and lactate trends. “I think it’s super critical to trend the lactate,” he states. He also emphasizes the importance of timing as a metric. Citing compelling data from the Inova group, Dr. Anderson remarks, “The thing that is astounding to me is that they had a 10% increase in mortality for every 60 minutes that there wasn’t support.” He thus concludes, “Escalation is something that needs to be considered, basically, immediately.”
Dr. Anderson wraps up his presentation by looking at the prevalence of biventricular failure, which occurs in about half of all patients in shock. He presents some Impella RP® heart pump survival outcomes and discusses the potential of CVP to be a simple metric for triggering further investigation in these patients.