Q1 / 110
A 40-year-old man with nonischemic cardiomyopathy (LVEF 20%) develops worsening cardiogenic shock despite inotropic therapy. He has moderate right ventricular dysfunction but no severe hypoxemia or circulatory collapse. The heart team wishes to stabilize him while evaluating him for transplantation. Which initial strategy is most appropriate?
Correct answer: C — Impella 5.5 for isolated left-sided support
The answer option including either Impella 5.5 or Impella CP would be reasonable. The size of Impella absolutely is not as important as being willing to adjust your flows to the need; for this case it is reasonable to say Impella 5.5 because it is more in line with our unit and a reasonable indication. Impella 5.5 provides temporary LV unloading and bridge-to-decision support while candidacy is assessed. It also has physiologic feedback that is worth recognizing: Impella 5.5 increases preload on the RV, but it also is associated with improvement in interventricular dependence with offloading of the LV. Silkowski et al found that Impella 5.5 on average decreased RAP from 12 to 9 and PCWP from 26 to 20 mmHg at 96 hours. In addition, they found that Impella 5.5 physiologic stress did not predict post-dLVAD RV failure. VA-ECMO provides more cardiopulmonary support than this physiology requires and increases LV afterload, while durable LVAD or total artificial heart implantation is premature before stabilization and reassessment.
Board pearl: The answer option including either Impella 5.5 or Impella CP would be reasonable; the size of Impella absolutely is not as important as being willing to adjust your flows to the need.
The answer option including either Impella 5.5 or Impella CP would be reasonable. The size of Impella absolutely is not as important as being willing to adjust your flows to the need; for this case it is reasonable to say Impella 5.5 because it is more in line with our unit and a reasonable indication. Impella 5.5 provides temporary LV unloading and bridge-to-decision support while candidacy is assessed. It also has physiologic feedback that is worth recognizing: Impella 5.5 increases preload on the RV, but it also is associated with improvement in interventricular dependence with offloading of the LV. Silkowski et al found that Impella 5.5 on average decreased RAP from 12 to 9 and PCWP from 26 to 20 mmHg at 96 hours. In addition, they found that Impella 5.5 physiologic stress did not predict post-dLVAD RV failure. VA-ECMO provides more cardiopulmonary support than this physiology requires and increases LV afterload, while durable LVAD or total artificial heart implantation is premature before stabilization and reassessment.
Board pearl: The answer option including either Impella 5.5 or Impella CP would be reasonable; the size of Impella absolutely is not as important as being willing to adjust your flows to the need.
Source(s): Panuccio et al. Use of Impella device in cardiogenic shock and its clinical outcomes: A systematic review and meta-analysis. Int J Cardiol Heart Vasc. 2022 Mar 25;40:101007. doi: 10.1016/j.ijcha.2022.101007. | Silkowski et al. Effects of Impella 5.5 on right ventricular load and adaptation. The Journal of Heart and Lung Transplantation. 2026 May. doi.org/10.1016/j.healun.2026.05.001.
Q2 / 110
Which characteristic distinguishes the Impella 5.5 from smaller Impella devices?
Correct answer: A — It can provide approximately 5–6 L/min and requires axillary or direct aortic insertion
The Impella 5.5 offers high-flow LV support and is placed through the axillary artery or directly into the aorta. DanGer Shock is one of the main articles currently showing improved mortality in utilization of microaxial flow pumps. DanGer Shock took patients who were in the acute phase of STEMI-related cardiogenic shock and demonstrated a lower risk of death from any cause at 180 days than standard care alone, though it had an increase in adverse events noted as moderate or severe bleeding, limb ischemia, hemolysis, device failure, and worsening of aortic regurgitation. The DanGer Shock microaxial flow intervention was the Impella CP, not the 5.5, although both study groups could escalate to the 5.5. When critically evaluating MCS, evaluate the amount of support needed. While the CP allows less flow, in some cases such as post-STEMI with reasonable assurance that quick recovery could happen, that may be enough to support through certain etiologies of cardiogenic shock.
Board pearl: When critically evaluating MCS, evaluate the amount of support needed; the DanGer Shock microaxial flow intervention was the Impella CP, not the 5.5.
The Impella 5.5 offers high-flow LV support and is placed through the axillary artery or directly into the aorta. DanGer Shock is one of the main articles currently showing improved mortality in utilization of microaxial flow pumps. DanGer Shock took patients who were in the acute phase of STEMI-related cardiogenic shock and demonstrated a lower risk of death from any cause at 180 days than standard care alone, though it had an increase in adverse events noted as moderate or severe bleeding, limb ischemia, hemolysis, device failure, and worsening of aortic regurgitation. The DanGer Shock microaxial flow intervention was the Impella CP, not the 5.5, although both study groups could escalate to the 5.5. When critically evaluating MCS, evaluate the amount of support needed. While the CP allows less flow, in some cases such as post-STEMI with reasonable assurance that quick recovery could happen, that may be enough to support through certain etiologies of cardiogenic shock.
Board pearl: When critically evaluating MCS, evaluate the amount of support needed; the DanGer Shock microaxial flow intervention was the Impella CP, not the 5.5.
Source(s): Moller et al. Microaxial Flow Pump or Standard Care in Infarct-Related Cardiogenic Shock. The New England Journal of Medicine. 2024 Apr;390:1382-1393.
Q3 / 110
Temporary MCS is initiated while a team determines whether a patient should proceed to transplantation, durable LVAD, or myocardial recovery. Which bridge strategy is this?
Correct answer: C — Bridge to decision
Bridge to decision buys time to clarify prognosis and definitive therapy. It is worth noting that temporary MCS is an ethically challenging situation. This frequently requires reassessment of cardiopulmonary recovery, risk of multiple organ dysfunction, and continued shared decision-making with various possible transition points from tMCS to native cardiopulmonary recovery, heart transplantation, durable LVAD, or palliative discontinuation. Bridge to recovery assumes recovery is expected. Bridge to transplant assumes transplant acceptance. Destination therapy is permanent support without transplant intent. Bridge to candidacy targets reversal of a known contraindication rather than general uncertainty.
Board pearl: Temporary MCS is an ethically challenging situation that frequently requires reassessment and continued shared decision-making.
Bridge to decision buys time to clarify prognosis and definitive therapy. It is worth noting that temporary MCS is an ethically challenging situation. This frequently requires reassessment of cardiopulmonary recovery, risk of multiple organ dysfunction, and continued shared decision-making with various possible transition points from tMCS to native cardiopulmonary recovery, heart transplantation, durable LVAD, or palliative discontinuation. Bridge to recovery assumes recovery is expected. Bridge to transplant assumes transplant acceptance. Destination therapy is permanent support without transplant intent. Bridge to candidacy targets reversal of a known contraindication rather than general uncertainty.
Board pearl: Temporary MCS is an ethically challenging situation that frequently requires reassessment and continued shared decision-making.
Source(s): Olive et al. Bridge to Decision, Bridge to Nowhere: Ethical and Clinical Challenges in Temporary Mechanical Circulatory Support. Journal of Cardiac Failure- Intersection. 2026 Mar 2;2:101016. doi.org/10.1016/j.yjcafi.2025.11.006.
Q4 / 110
Which physiologic effect is primarily responsible for the benefit of Impella support?
Correct answer: B — Direct LV unloading with reduced wall stress
Impella removes blood from the LV and delivers it to the ascending aorta, lowering LV volume, pressure, wall stress, and oxygen demand. ECMO supports circulation; Impella directly unloads the LV. Further improvements as noted by Silkowski et al. include favorable right-sided physiologic responses that accompany LV offloading rather than simple isolated forward flow augmentation.
Board pearl: Impella directly unloads the LV, with further physiologic improvements as noted by Silkowski et al.
Impella removes blood from the LV and delivers it to the ascending aorta, lowering LV volume, pressure, wall stress, and oxygen demand. ECMO supports circulation; Impella directly unloads the LV. Further improvements as noted by Silkowski et al. include favorable right-sided physiologic responses that accompany LV offloading rather than simple isolated forward flow augmentation.
Board pearl: Impella directly unloads the LV, with further physiologic improvements as noted by Silkowski et al.
Source(s): Silkowski et al. Effects of Impella 5.5 on right ventricular load and adaptation. The Journal of Heart and Lung Transplantation. 2026 May. doi.org/10.1016/j.healun.2026.05.001.
Q5 / 110
A patient develops isolated severe RV failure after durable LVAD implantation. Oxygenation and LVAD function are adequate. Which temporary support strategy is most appropriate?
Correct answer: C — Impella RP
Impella RP bypasses the failing RV and returns venous blood to the pulmonary artery. The key study is RECOVER RIGHT, a prospective, nonrandomized, single-arm study of 30 patients with right-heart failure due to status post LVAD implantation, cardiotomy, or myocardial infarction. It was not a randomized trial, but it demonstrated immediate hemodynamic benefit and was designed to establish safety and immediate hemodynamic benefit of the Impella RP (industry-funded by Abiomed). Of note, the FDA issued a safety communication after postmarket use of Impella RP outside the study's inclusion criteria was associated with higher mortality, underscoring the importance of appropriate patient selection. Femoral VA-ECMO is more support than needed when oxygenation is adequate. Impella CP supports the LV, not the RV. Intra-aortic balloon pump provides little support for isolated severe RV failure.
Board pearl: RECOVER RIGHT was a prospective, nonrandomized, single-arm study (not an RCT); the FDA later flagged higher mortality with off-protocol Impella RP use outside the studied population.
Impella RP bypasses the failing RV and returns venous blood to the pulmonary artery. The key study is RECOVER RIGHT, a prospective, nonrandomized, single-arm study of 30 patients with right-heart failure due to status post LVAD implantation, cardiotomy, or myocardial infarction. It was not a randomized trial, but it demonstrated immediate hemodynamic benefit and was designed to establish safety and immediate hemodynamic benefit of the Impella RP (industry-funded by Abiomed). Of note, the FDA issued a safety communication after postmarket use of Impella RP outside the study's inclusion criteria was associated with higher mortality, underscoring the importance of appropriate patient selection. Femoral VA-ECMO is more support than needed when oxygenation is adequate. Impella CP supports the LV, not the RV. Intra-aortic balloon pump provides little support for isolated severe RV failure.
Board pearl: RECOVER RIGHT was a prospective, nonrandomized, single-arm study (not an RCT); the FDA later flagged higher mortality with off-protocol Impella RP use outside the studied population.
Source(s): Anderson et al. Benefits of a novel percutaneous ventricular assist device for right heart failure: The prospective RECOVER RIGHT study of the Impella RP device. J Heart Lung Transplant. 2015 Dec;34(12):1549-60. | Anderson et al. Benefits of a Novel Percutaneous Ventricular Assist Device for Right Heart Failure: The Prospective RECOVER RIGHT Study of the Impella RP Device. J Heart Lung Transplant. 2015 Dec;34(12):1549-60. doi:10.1016/j.healun.2015.08.018.