Authors: Soomal Rafique, Raj Patel, Asad Cheema, Tony DeMartini, Abdul Moiz Hafiz
Categories: Heart Failure and Cardiomyopathies, cardiogenic shock (CS), hemodynamics, Impella, percutaneous left ventricular assist device (LVAD), right heart catheterization (RHC)
Source: JACC Case Reports
Authors: Soomal Rafique, Raj Patel, Asad Cheema, Tony DeMartini, Abdul Moiz Hafiz
Mortality rates for cardiogenic shock (CS) remain high, but the development of percutaneous left ventricular assist devices and the adoption of a shock-team approach, which emphasizes early use of mechanical circulatory support (MCS) devices and hemodynamic monitoring, has been shown to improve outcomes. The introduction of the Impella CP and Impella 5.5 has expanded options for left ventricular temporary MCS. This case series highlights our experience managing patients with CS using a shock protocol escalation strategy from Impella CP to Impella 5.5. Notably, all cases reflect the decision-making process of transitioning to a different MCS modality quickly based on real-time hemodynamic data. We believe our shock protocol can be easily adapted by most US hospitals with cardiac catheterization laboratories and can be replicated in most settings with minimal adjustments.
Visual SummaryEscalation of Impella CP to Impella 5.5 in Cardiogenic Shock
Mortality due to cardiogenic shock (CS) remains high, with rates between 50% and 80% in earlier studies^1^ and 40% to 60% reported by more recent studies.^2^ Many patients first present to hospitals lacking advanced heart failure (HF) treatment capabilities,^3^ including mechanical circulatory support (MCS) options (eg, extracorporeal membrane oxygenation [ECMO], percutaneous left ventricular assist device [pLVAD], transplant), with centralized resources in quaternary centers, which can worsen outcomes. This limits timely access for much of the population. A pLVAD helps decentralize care, being less resource intensive; however, effective use requires clinical expertise. Shock-team models have shown improved CS outcomes,^4^^,^^5^ emphasizing early MCS use and hemodynamic-guided management. Among MCS devices, Impella (Abiomed), is the only widely available pLVAD approved by the US Food and Drug Administration for dedicated left ventricular (LV) or right ventricular (RV) support. Impella CP and Impella 5.5 have broadened temporary LV support options, aiding recovery or bridging patients to advanced heart failure centers.Take-Home Messages•The use of microaxial pumps in CS can provide critical support in resource-limited settings and enable patient stabilization or transfer to advanced HF centers.•Implementing a shock algorithm can possibly provide a guide for better approach with early MCS and hemodynamic monitoring as demonstrated by this single-center case series using a stepwise escalation strategy.
This case series highlights our management experience at a tertiary care center lacking an advanced heart failure program with patients presenting with CS using a shock protocol escalation strategy starting with the Impella CP and proceeding to the Impella 5.5 with or without the Impella RP. This project was reviewed by our local institutional review board and determined as non–human subject research. Table 1 presents the hemodynamics used to guide management, and Table 2 summarizes the case series.Table 1Hemodynamics According to Right Heart CatheterizationCase 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8Pulmonary artery pressures, systolic/diastolic/mean, mm Hg52/32/40—32/18/2329/10/2244/21/3235/20/2827/18/2232/20/25Mixed venous oxygen saturation, %39.6—34.256—69.964.949Pulmonary artery pulsatility index>1.10.750.91.491.3<11.31.4Pulmonary capillary wedge pressure, mm Hg36——16231717—Left ventricle pressures, systolic/diastolic/end-diastolic, mm Hg——61/11/1180/16/17————Cardiac output, L/min34.41.40.4736.23.90.5Cardiac index, L/min/m^2^2.42.511.61.43.42.21.0Cardiac power output0.490.750.190.050.430.700.782.2Systemic vascular resistance, dynes/s/cm^−5^1,5351,1283,6002,7801,147—3,4372,100Table 2Summary of Case SeriesCase 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8Age, y/sex55/M47/M78/F35/F62/M69/M47/M76/MEtiology of cardiogenic shockSTEMISTEMIPost cardiotomyMyocarditisNonischemic CMP, AFibSTEMISTEMIPost cardiotomyIndication for escalationRefractory shockRefractory shockRefractory shockRefractory shockRefractory shockRefractory shockRefractory shockRefractory shockDevices used, duration, × dImpella CP × 1Impella 5.5 × 14Impella CP × 1Impella 5.5 × 30IABP × 1Impella 5.5 × 5Impella RP × 5Impella CP × 1Impella 5.5 × 13Impella RP × 13Impella CP × <1Impella 5.5 × 1Impella RP × 1Impella CP × <1Impella 5.5 × 1Impella RP × 1Impella CP × <1Impella 5.5 × 6IABP × 1Impella CP × 1Impella 5.5 × 1Impella RP × 1OutcomeTransferred for transplant/VAD evaluation, followed by deathTransferred for transplant/VADImproved, but followed by multiorgan failure and hospiceTransferred for transplant/VAD, followed by recoveryTransferred for transplant/VAD, followed by deathTransferred for transplant/VAD followed by recoveryBridge to recoveryTransferred for transplant/VAD followed by recoveryDevice-related complicationNoneNoneNoneNoneNoneNoneChest wall hematomaNoneAFib = atrial fibrillation; CMP = cardiomyopathy; F = female; IABP = intra-aortic balloon pump; M = male; STEMI = ST-segment elevation myocardial infarction; VAD = ventricular assist device.
A 55-year-old man with hypertension and hyperlipidemia presented to the emergency department (ED) with chest pain 5 days after a percutaneous coronary intervention (PCI) of the left anterior descending coronary artery (LAD) and left circumflex coronary artery. Owing to an anterior ST-segment elevation myocardial infarction (STEMI) and shock, emergent coronary angiography was advised. While en route to the catheterization laboratory, the patient required cardioversion for an episode of ventricular tachycardia. Coronary angiography revealed thrombosed prior stents. Balloon angioplasty was performed on the thrombosed LAD stent, but the left circumflex coronary artery could not be treated. Despite maximal vasopressor support and the Impella CP, a right heart catheterization (RHC) showed severe LV dominant CS necessitating upgrade to an Impella 5.5. Thereafter, vasopressor requirements were reduced with improved hemodynamics. Left ventricular ejection fraction (LVEF) improved to 20% to 25%. Owing to inability to wean the pLVAD after a week, he was transferred to an advanced HF center. The patient was deemed not to be a candidate for advanced HF therapies and subsequently was transitioned to comfort care.
A 47-year-old man with a history of coronary artery disease status post coronary artery bypass graft (CABG) surgery and multiple PCIs, presented to the ED with chest pain. Electrocardiography showed an inferior wall STEMI with elevated high-sensitivity troponin level of 224 ng/mL. Coronary angiography showed severe stenosis in the posterior descending artery and at the saphenous vein graft to obtuse marginal 1 artery anastomosis site, along with a patent left internal mammary artery (LIMA) graft. Transthoracic echocardiography (TTE) showed preserved LVEF with inferior hypokinesis. Owing to the patient's history of medication noncompliance, redo CABG surgery was performed, which was complicated by LIMA damage requiring repair. Postoperatively, he developed persistent hypotension despite intra-aortic balloon pump (IABP) placement and maximal inotropic support. He had worsening lactic acidosis (15 mmol/L) and RV ejection fraction and LVEF (<10%). RHC showed reduced cardiac output and pulmonary artery pulsatility index (PAPi). Coronary angiography showed an occluded LIMA graft, not amenable to revascularization. An Impella 5.5 device was placed for further MCS, a marked reduction in lactic acidosis, and vasopressor requirement. He was transferred to an advanced HF center, where he was supported with the Impella 5.5 for 30 days. Following this period, the received a HeartMate 3 (Abbott) left ventricular assist device (LVAD) as destination therapy.
A 78-year-old woman with a bicuspid aortic valve, severe aortic stenosis, and ascending aortic aneurysm was admitted for elective bioprosthetic aortic valve replacement and ascending aorta replacement, complicated by biventricular failure and shock requiring multiple vasopressors and IABP immediately postoperatively. Advanced CS with cardiometabolic derangements had set in before the shock team was activated the day after surgery. RHC revealed CS, and coronary angiography showed iatrogenic left main coronary artery (LMCA) occlusion, not amenable to PCI. TTE showed severely reduced LVEF at 18% from 59%, when Impella CP was placed. Owing to worsening PAPi (from 1.7 to 0.2) and rising lactate (peak 19 mmol/L), an Impella RP was inserted, and the Impella CP was upgraded to Impella 5.5. Post–biventricular Impella placement, mean arterial pressure improved. The postoperative course was complicated by refractory multiorgan failure, atrial fibrillation, and seizures. The patient died shortly after the family opted for comfort measures.
A 35-year-old woman with recent COVID-19 infection presented to the ED with dyspnea and was diagnosed with septic shock secondary to COVID-19 pneumonia requiring pressors. TTE revealed an ejection fraction of 25% to 30%, with multiple wall motion abnormalities and a dilated RV. RHC revealed hemodynamics consistent with CS. Cardiomyopathy was thought to result from sepsis or COVID-19-related myocarditis. Coronary angiography was unremarkable. Given severe CS, an Impella CP was inserted without any improvement in cardiac index and lactic acidosis requiring escalation to an Impella 5.5. An Impella RP was placed for RV failure. Post–biventricular Impella placement, the vasopressor requirements were reduced, urine output improved, and lactate levels decreased from 7.3 to 2.4 mmol/L. The patient was transferred to another facility for possible venoarterial ECMO, which was deemed unnecessary on arrival. She was discharged after a 2-week hospital stay, making a full recovery.
A 62-year-old man presented to the ED with shortness of breath and was found to have new-onset atrial fibrillation with rapid ventricular response. After undergoing emergent cardioversion, his condition deteriorated into CS. RHC showed biventricular failure. Coronary angiography revealed nonobstructive disease. An Impella CP was inserted but had to be upgraded in the same session to an Impella 5.5 owing to worsening lactic acidosis and hemodynamics. Secondary to severe RV failure, an Impella RP was inserted. He required intubation, continuous renal replacement therapy for anuria and acidosis (peak lactate 8.8 mmol/L), and vasopressors. The patient remained intubated and was transferred to another facility for advanced support, where he died after his family transitioned him to comfort care per the patient’s advance directive to avoid life support measures.
A 69-year-old man with diabetes mellitus, hypertension, and hyperlipidemia presented to the ED with chest pain, and electrocardiography showed an anterior STEMI. Coronary angiography revealed 90% proximal LAD stenosis and 80% proximal right coronary artery stenosis. He underwent emergent high-risk PCI to the LAD; later on in the intensive care unit, complications occurred including complete heart block, ventricular fibrillation, and cardiac arrest requiring approximately 60 minutes of cardiopulmonary resuscitation. Repeat angiography showed nonocclusive in-stent LAD thrombosis requiring aspiration thrombectomy. Post-procedure, he remained in CS (LVEF <10%), requiring vasopressors, a transvenous pacer, and an Impella CP, which was escalated to Impella 5.5 owing to persistent hypotension and inability to maximize Impella CP flows. Given PAPi <1, an Impella RP was also inserted. With volume resuscitation, Impella flows improved, and lactic acidosis decreased from 13.3 to 6.9 mmol/L. The patient was transferred to an advanced heart failure center, where he recovered completely and LVEF normalized.
A 47-year-old man with hypertension and hyperlipidemia presented with anterior STEMI. Coronary angiography revealed severe obstructive multivessel disease. He developed ventricular fibrillation arrest in the catheterization laboratory, requiring defibrillation; Impella CP placement for shock; and PCI to LMCA, LAD, and obtuse marginal 1 artery. RHC showed low cardiac index and elevated filling pressures; TTE demonstrated LVEF <20%. As a result of persistent shock and rising lactate (peak 7.8 mmol/L), the Impella CP was escalated to an Impella 5.5, complicated by chest wall hematoma requiring evacuation. The patient gradually improved with weaning of vasoactive support, normalization of lactate (1.0 mmol/L), central venous pressure of 6 cm H2O, and PA saturation of 68%. The Impella 5.5 was removed on day 6. The patient was transferred to the floor and later discharged home in stable condition.
A 76-year-old man with hypertension and hyperlipidemia was referred from clinic for ischemic evaluation following new-onset left bundle branch block. Coronary angiography revealed multivessel obstructive disease including the LMCA. He subsequently underwent CABG surgery, complicated by intraoperative shock, requiring an Impella CP, later upgraded to Impella 5.5 owing to persistently low mixed venous oxygen saturation despite maximum support (P8). The patient then developed complete heart block with loss of capture from epicardial leads, requiring resuscitation with brief cardiopulmonary resuscitation. An Impella RP was placed for right ventricular failure that preceded cardiac arrest, and a temporary transvenous pacemaker was inserted for bradycardia. Post–biventricular support, repeat angiography showed patent grafts. Despite slight improvement in lactate levels (4.7-2.7 mmol/L), cardiac power output of 0.4 W, and a PAPi of 0.3, the patient was transferred to a higher-level facility, where venopulmonary ECMO was initiated, facilitating as of last update extubation with the patient sitting upright.
Previous data have suggested that most patients with CS in the United States are treated at hospitals without LVAD or transplant availability, and patients treated at centers lacking LVADs have worse outcomes.^3^^,^^6^ This underscores the critical role of temporary mechanical circulatory devices that provide time for recovery or transfer. A survey published a few years ago found that approximately 44% of centers used MCS for CS, of which 92% had access to IABP, 78% had access to Impella, and 60% had access to ECMO.^7^ In contrast to ECMO, which provides oxygenation, Impella is particularly popular owing to ease of use, being less resource intensive, and decreasing myocardial oxygen demand by reducing LV afterload. Patients with an Impella 5.5 can ambulate, an option not easily available with use of femoral cannulated MCS devices. Escalation from the Impella CP to Impella 5.5 is essential for patients unresponsive to initial CP treatment. Our institutional protocol was drafted based on contemporary data in 2020, iterated, and finally approved by consensus in February 2022 by all credentialed interventional cardiologists at our institution, based on best understanding of CS data available then. We drew inspiration from the National Cardiogenic Shock Initiative protocol,^8^ the only standardized registry-based protocol at that time, and adapted it to our local infrastructure and expertise. Our protocol for use and escalation of Impella devices is shown in Figure 1. We employ a multidisciplinary team including intensivists, interventional cardiologists, and cardiothoracic surgeons, supported by experienced critical care staff for hemodynamic monitoring and decision making. Our protocol prioritizes early CS recognition, classification, and intervention in patients with acute myocardial infarction and is extended to most patients with CS when applicable. The Impella CP is typically the initial MCS, followed by hemodynamic assessment to guide escalation and coronary revascularization when feasible. Continuous monitoring informs timely MCS escalation or de-escalation. Frequent tracking of acidosis, lactate level, and end-organ damage is performed. Optimal outcomes occurred in cases in our experience when rapid MCS transitions based on real-time data were made.Figure 1Memorial Hospital Cardiogenic Shock AlgorithmCPO = cardiac power output; ECMO = extracorporeal membrane oxygenation; LV = left ventricular; LVAD = left ventricular assist device; PAPi = pulmonary artery pulsatility index; PCI = percutaneous coronary intervention; RV = right ventricular.
Our shock protocol was a voluntary protocol and not mandated, which made adoption nonuniform. Only cases that followed the protocol were included in this case series. Replicability in other settings is unknown, and objective outcome data are not yet available.
A rapid escalation strategy driven by a predefined hemodynamic algorithm using various Impella devices in above-described case series involves significant clinical judgment and objective identification of CS type. This helps create a structured framework to effectively manage and navigate these complex clinical scenarios. Outcomes in this small case series varied based on presentation, underlying etiology, and timing of intervention. Adherence to the protocol supported consistent clinical decision making in this case series.
Dr Hafiz is a consultant for ReCor Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.