Team Approach to the Management of Shock: AMI Cardiogenic Shock Cases and Discussion (Part 2)

Case 1: Hemodynamics and Escalation

Presentation

Jeffrey Marbach, MD, an interventional cardiologist and cardiac critical care fellow at Tufts Medical Center in Boston, opens this portion of the TAMS event by presenting the first case. The patient is a 72-year-old patient with anterior STEMI who developed VF arrest during PCI. Due to cardiogenic shock, Impella CP® heart pump was placed and the patient was transferred to Tufts for further management.

Dr. Marbach explains that the patient was on 3 pressors and Impella® support at P-6 on arrival to Tufts with a lactate of 12.4. At this point in the presentation, Dr. Marbach presents three potential next steps:

• Should the patient continue with medical therapy to give the LV time to recover?
• Should the team upgrade LV support?
• Does the patient require initiation of RV support?

The patient showed very little improvement in lactate trends after 6 to 8 hours of medical management post-PCI. Dr. Marbach discusses lactate washout data, and the importance of lactate washout/clearance, or lack thereof, as a surrogate for mortality in cardiogenic shock. With evidence of failure to clear lactate with initial strategies, he emphasizes, “we really need to look at escalating support.”

The patient’s PAPi level (0.67) and RA/PCWP (0.87) indicated severe right ventricular failure. Given these parameters of RV dysfunction and the elevated lactate, the team decided to place this patient on venoarterial (VA) extracorporeal membrane oxygenation (ECMO). Within a few hours the patient was taken off levophed, phenylephrine, and vasopressin, and lactate returned to normal within 24 hours of arrival. The patient was decannulated from ECMO on day 6, Impella heart pump was removed on day 7 and on day 21 TTE showed normal size LV with LVEF 30%, normal size RV and function, and no significant valve disease. “A very good outcome in this patient who was critically ill,” Dr. Marbach concludes.

Discussion

In the ensuing discussion, Dr. O’Neill and Dr. Kapur discuss the importance of hemodynamics and the impact of Impella to ECMO escalation on heart recovery. Notably, Dr. Kapur discusses the importance of upfront LV unloading prior to initiation of VA ECMO, as compared to initiating VA ECMO and then bailout LV unloading. He also emphasizes the significant difference between “LV venting” (reducing LV filling pressure) and “LV unloading” (reduction in LV pressure and volume). 

Case 2: Vascular Access and Team Collaboration

Presentation

Haval Chweich, MD, a CCU intensivist pulmonary and critical care attending physician at Tufts Medical Center, offers the case of a 71-year-old patient presenting to an outside hospital with chest pain. The patient was placed on intra-aortic balloon pump (IABP) and transferred to Tufts Medical Center for surgical consult. Overnight, he was overactive and pulled out the balloon pump and his condition deteriorated. At this point, Dr. Chweich notes that potential next steps were inotropes, IABP, Impella CP®, or ECMO.

This patient had significant peripheral vascular disease with a very tight left iliac artery and a spiral dissection in his right iliac from pulling out the IABP. Given these access concerns and the patient’s unstable hemodynamics, the team took the patient to the cath lab and replaced the IABP, although they had a high degree of suspicion that it might not provide adequate support. They monitored hemodynamics and within a couple hours returned to the cath lab, placing Impella CP heart pump with an external fem-fem bypass. With adequate hemodynamic support the patient returned to the CCU and the team was able to defer revascularization and consult cardiac surgery. While the patient’s hemodynamics improved significantly, he was deemed too high risk for CABG and returned to the cath lab for PCI and stenting.

Dr. Chweich notes that this case highlights the need for close collaboration between cardiac, ICU, vascular, and cardiac surgery teams in complex cardiogenic shock patients.

Discussion

Following this case presentation, Dr. O’Neill and Dr. Kapur discuss issues of vascular management and alternate access techniques. Dr. O’Neill explains that his approach would be to think about how to get the patient supported with the largest support device in a safe manner. Dr. Kapur reflects on how the case illustrates that AMI shock is probably not the place for IABP utilization and he emphasizes the importance of uniformly following algorithms and protocols. He also discusses the importance of shock operators and interventionalists being comfortable with a broad range of vascular access techniques. 

Case 3: Heart Failure Shock

Presentation

Dr. Marbach presents a second case, this time a 49-year-old patient with heart failure shock, which has different hemodynamic and hemometabolic profiles than AMI shock. This patient had been decompensating and came in for a right heart cath and evaluation for transplant. Dr. Marbach emphasizes that recent data supports the use of PA catheters in shock patients and he mentions a 2020 paper by Garan et al. from J Am Coll Cardiol HF showing that across all SCAI stages, patients with complete hemodynamic profiling have lower overall mortality.

The patient was admitted to the hospital and started on milrinone. Following frequent ventricular ectopy and a sustained VT episode on milrinone, along with the need to increase cardiac index, the team evaluated the patient for MCS. The team placed an IABP but over the next 24 hours RA pressure began to rise, PCWP ticked up, and CI didn’t budge. Given that this patient had chronic heart failure and was being evaluated for transplant, the team determined that he needed longer duration support. They placed an axillary Impella 5.5® with SmartAssist® heart pump which provided more support, unloaded the left ventricle, and allowed the patient to ambulate and participate in rehab as he awaited heart transplant.

Discussion

Dr. Kapur followed this case with a brief discussion of the use of Impella 5.0® and Impella 5.5 with SmartAssist heart pumps as a means of bridging patients to transplant, decision, or to a lesser degree now, a durable device. “In our practice,” Dr. Kapur notes, “we’re now further embolden to use Impella 5.5 because now we can leave these patients on support for a period of months… ambulating, engaged in rehab, becoming optimal candidates for transplant.” Dr. Kapur also emphasizes that unloading the LV is one of the most effective ways to unload the RV.

Dr. O’Neill addresses approaches to AMI shock versus heart failure shock, stating that it still comes down to hemodynamics. “If you still have a CPO < 0.5 and you have elevated lactate, whatever support device you’re using is inadequate.” He explains that while there is still a place for IABP in decompensated heart failure and mild shock, it is becoming less frequently used. He concludes by emphasizing that members of the shock team need to be familiar with multiple techniques “so that you can tailor the technique to the patient, not the other way around.”