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Goffer EM, Lamberti KK, Spognardi AM, Edelman ER, Keller SP. Steady Flow Left Ventricle Unloading Is Superior to Pulsatile Pressure Augmentation Venting During Venoarterial Extracorporeal Membrane Oxygenation Support. ASAIO J 2024:00002480-990000000-00460. [PMID: 38588597 DOI: 10.1097/mat.0000000000002208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024] Open
Abstract
Venoarterial extracorporeal membrane oxygenation (VA-ECMO) shunts venous blood to the systemic arterial circulation to provide end-organ perfusion while increasing afterload that may impede left ventricle (LV) ejection and impair cardiac recovery. To maintain flow across the aortic valve and reduce risk of lethal clot formation, secondary mechanical circulatory support (MCS) devices are increasingly used despite limited understanding of their effects on cardiac function. This study sought to quantify the effects of VA-ECMO and combined with either intraaortic balloon pump (IABP) or percutaneous ventricular assist device (pVAD) on LV physiologic state and perfusion metrics in a porcine model of acute cardiogenic shock. Shock was induced through serial left anterior descending artery microbead embolization followed by initiation of VA-ECMO support and then placement of either IABP or pVAD. Hemodynamic measurements, LV pressure-volume loops, and carotid artery blood flow were evaluated before and after institution of combined MCS. The IABP decreased LV end-diastolic pressure by a peak of 15% while slightly increasing LV stroke work compared with decreases of more than 60% and 50% with the pVAD, respectively. The pVAD also demonstrated increased coronary perfusion and systemic pressure gradients in comparison to the IABP. Combined support with VA-ECMO and pVAD improves cardiovascular state in comparison to IABP.
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Affiliation(s)
- Efrat M Goffer
- From the Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Kimberly K Lamberti
- From the Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | | | - Elazer R Edelman
- From the Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Steven P Keller
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
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Lamberti KK, Keller SP, Edelman ER. Dynamic load modulation predicts right heart tolerance of left ventricular cardiovascular assist in a porcine model of cardiogenic shock. Sci Transl Med 2024; 16:eadk4266. [PMID: 38354226 DOI: 10.1126/scitranslmed.adk4266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/24/2024] [Indexed: 02/16/2024]
Abstract
Ventricular assist devices (VADs) offer mechanical support for patients with cardiogenic shock by unloading the impaired ventricle and increasing cardiac outflow and subsequent tissue perfusion. Their ability to adjust ventricular assistance allows for rapid and safe dynamic changes in cardiac load, which can be used with direct measures of chamber pressures to quantify cardiac pathophysiologic state, predict response to interventions, and unmask vulnerabilities such as limitations of left-sided support efficacy due to intolerance of the right heart. We defined hemodynamic metrics in five pigs with dynamic peripheral transvalvular VAD (pVAD) support to the left ventricle. Metrics were obtained across a spectrum of disease states, including left ventricular ischemia induced by titrated microembolization of a coronary artery and right ventricular strain induced by titrated microembolization of the pulmonary arteries. A sweep of different pVAD speeds confirmed mechanisms of right heart decompensation after left-sided support and revealed intolerance. In contrast to the systemic circulation, pulmonary vascular compliance dominated in the right heart and defined the ability of the right heart to adapt to left-sided pVAD unloading. We developed a clinically accessible metric to measure pulmonary vascular compliance at different pVAD speeds that could predict right heart efficiency and tolerance to left-sided pVAD support. Findings in swine were validated with retrospective hemodynamic data from eight patients on pVAD support. This methodology and metric could be used to track right heart tolerance, predict decompensation before right heart failure, and guide titration of device speed and the need for biventricular support.
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Affiliation(s)
- Kimberly K Lamberti
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Steven P Keller
- Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MA 21205, USA
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Aslam MI, Gruslova AB, Almomani A, Nolen D, Elliott JJ, Jani VP, Kottam A, Porterfield J, Heighten C, Anderson AS, Valvano JW, Feldman MD. Modification of a Transvalvular Microaxial Flow Pump for Instantaneous Determination of Native Cardiac Output and Volume. J Card Fail 2023; 29:1369-1379. [PMID: 37105397 DOI: 10.1016/j.cardfail.2023.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 04/10/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023]
Abstract
BACKGROUND The current Impella cardiopulmonary (CP) pump, used for mechanical circulatory support in patients with cardiogenic shock (CS), cannot assess native cardiac output (CO) and left ventricular (LV) volumes. These data are valuable in facilitating device management and weaning. Admittance technology allows for accurate assessment of cardiac chamber volumes. OBJECTIVES This study tested the ability to engineer admittance electrodes onto an existing Impella CP pump to assess total and native CO as well as LV chamber volumes in an instantaneous manner. METHODS Impella CP pumps were fitted with 4 admittance electrodes and were placed in the LVs of adult swine (n = 9) that were subjected to 3 different hemodynamic conditions, including Impella CP speed adjustments, administration of escalating doses of dobutamine and microsphere injections into the left main artery to result in cardiac injury. CO, according to admittance electrodes, was calculated from LV volumes and heart rate. In addition, CO was calculated in each instance via thermodilution, continuous CO measurement, the Fick principle, and aortic velocity-time integral by means of echocardiography. RESULTS Modified Impella CP pumps were placed in swine LVs successfully. CO, as determined by admittance electrodes, was similar by trend to other methods of CO assessment. It was corrected for pump speed to calculate native CO, and calculated LV chamber volumes trended as expected in each experimental protocol. CONCLUSIONS We report, for the first time, that an Impella CP pump can be fitted with admittance electrodes and used to determine total and native CO in various hemodynamic situations. CONDENSED ABSTRACT Transvalvular mechanical circulatory support devices such as the Impella CP do not have the ability to provide real-time information on native cardiac output (CO) and left ventricular (LV) volumes. This information is critical in device management and in weaning in patients with cardiogenic shock. We demonstrate, for the first time, that Impella CP pumps coupled with admittance electrodes are able to determine native CO and LV chamber volumes in multiple hemodynamic situations such as Impella pump speed adjustments, escalating dobutamine administration and cardiac injury from microsphere injection.
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Affiliation(s)
- M Imran Aslam
- Department of Medicine, Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Aleksandra B Gruslova
- Department of Medicine, Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Ahmed Almomani
- Department of Medicine, Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Drew Nolen
- Department of Medicine, Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - James J Elliott
- Department of Laboratory Animal Resources, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Vivek P Jani
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Anil Kottam
- BridgeSource Medical Corporation, Austin, Texas
| | | | | | - Allen S Anderson
- Department of Medicine, Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Jonathan W Valvano
- Department of Electrical Engineering, University of Texas at Austin, Austin, Texas
| | - Marc D Feldman
- Department of Medicine, Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
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Chang BY, Zhang Z, Feng K, Josephy N, Keller SP, Edelman ER. Hysteretic device characteristics indicate cardiac contractile state for guiding mechanical circulatory support device use. Intensive Care Med Exp 2021; 9:62. [PMID: 34928472 PMCID: PMC8688616 DOI: 10.1186/s40635-021-00426-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 12/10/2021] [Indexed: 11/10/2022] Open
Abstract
Background Acute heart failure and cardiogenic shock remain highly morbid conditions despite prompt medical therapy in critical care settings. Mechanical circulatory support (MCS) is a promising therapy for these patients, yet remains managed with open-loop control. Continuous measure of cardiac function would support and optimize MCS deployment and weaning. The nature of indwelling MCS provides a platform for attaining this information. This study investigates how hysteresis modeling derived from MCS device signals can be used to assess contractility changes to provide continuous indication of changing cardiac state. Load-dependent MCS devices vary their operation with cardiac state to yield a device–heart hysteretic interaction. Predicting and examining this hysteric relation provides insight into cardiac state and can be separated by cardiac cycle phases. Here, we demonstrate this by predicting hysteresis and using the systolic portion of the hysteresis loop to estimate changes in native contractility. This study quantified this measurement as the enclosed area of the systolic portion of the hysteresis loop and correlated it with other widely accepted contractility metrics in animal studies (n = 4) using acute interventions that alter inotropy, including a heart failure model. Clinical validation was performed in patients (n = 8) undergoing Impella support. Results Hysteresis is well estimated from device signals alone (r = 0.92, limits of agreement: − 0.18 to 0.18). Quantified systolic area was well correlated in animal studies with end-systolic pressure–volume relationship (r = 0.84), preload recruitable stroke work index (r = 0.77), and maximum slope of left ventricular pressure (dP/dtmax) (r = 0.95) across a range of inotropic conditions. Comparable results were seen in patients with dP/dtmax (r = 0.88). Diagnostic capability from ROC analysis yielded AUC measurements of 0.92 and 0.90 in animal and patients, respectively. Conclusions Mechanical circulatory support hysteretic behavior can be well modeled using device signals and used to estimate contractility changes. Contractility estimate is correlated with other accepted metrics, captures temporal trends that elucidate changing cardiac state, and is able to accurately indicate changes in inotropy. Inherently available during MCS deployment, this measure will guide titration and inform need for further intervention.
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Affiliation(s)
- Brian Y Chang
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.,Program in Health Sciences and Technology, Harvard Medical School, Boston, MA, USA
| | - Zhengyang Zhang
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kimberly Feng
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Noam Josephy
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.,Abiomed, Danvers, MA, USA
| | - Steven P Keller
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.,Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA, USA.
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The author replies. Crit Care Med 2021; 48:e332-e333. [PMID: 32205625 DOI: 10.1097/ccm.0000000000004265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chang BY, Moyer C, Katerji AE, Keller SP, Edelman ER. A Scalable Approach to Determine Intracardiac Pressure From Mechanical Circulatory Support Device Signals. IEEE Trans Biomed Eng 2020; 68:905-913. [PMID: 32784129 DOI: 10.1109/tbme.2020.3016220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Effective mechanical circulatory support (MCS) relies on cardiac function measures to guide titration. Left ventricular end diastolic pressure (LVEDP) is a useful measure that is indirectly estimated using pulmonary artery catheters (PACs). PACs require additional intervention and provide intermittent and unreliable estimations. MCS device signals can estimate LVEDP but are prone to inter-device variability and require rigorous specialized characterization. We present a scalable and implementable approach to calculate LVEDP continuously using device signals. METHODS LVEDP was calculated from MCS device measured aortic pressure and motor current, which approximates the pressure head between the aorta and left ventricle. This motor current-pressure head relationship is device-specific but approximated using existing flow calibration and assumed physiologic relationships. Performance was evaluated with comparison from direct measurement of LVEDP in a series of acute animal models. RESULTS LVEDP measures (n = 178,279) from 18 animals had good correlation (r = 0.84) and calibration (Bland-Altman limits of agreement -7.77 to 7.63 mmHg; mean bias -0.07 ± 0.02 mmHg). The total mean error prediction interval was -3.42 to 3.32 mmHg and RMS error was 3.85 mmHg. CONCLUSION LVEDP can be continuously calculated using device signals without specialized characterization. Calculated LVEDP values improved upon PAC estimations and were found using a scalable and manufacturer-accessible method. SIGNIFICANCE This method improves upon existing LVEDP measures without the need for rigorous characterization, external calibration, or additional intervention; this allows widescale deployment of continuous LVEDP measurement for patients on MCS and demonstrates key considerations necessary to translate research-grade technologies.
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Keller SP, Chang BY, Tan Q, Zhang Z, El Katerji A, Edelman ER. Dynamic Modulation of Device-Arterial Coupling to Determine Cardiac Output and Vascular Resistance. Ann Biomed Eng 2020; 48:2333-2342. [PMID: 32285344 DOI: 10.1007/s10439-020-02510-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/07/2020] [Indexed: 11/24/2022]
Abstract
Clinical adoption of mechanical circulatory support for shock is rapidly expanding. Achieving optimal therapeutic benefit requires metrics of state to guide titration and weaning of support. Using the transvalvular positioning of a percutaneous ventricular assist device (pVAD), device:heart interactions are leveraged to determine cardiac output (CO) and systemic vascular resistance (SVR) near-continuously without disrupting therapeutic function. An automated algorithm rapidly alternates between device support levels to dynamically modulate physiological response. Employing a two-element lumped parameter model of the vasculature, SVR and CO are quantified directly from measurements obtained by the pVAD without external calibration or invasive catheters. The approach was validated in an acute porcine model across a range of cardiac (CO = 3-10.6 L/min) and vascular (SVR = 501-1897 dyn s/cm5) states. Cardiac output calculations closely correlated (r = 0.82) to measurements obtained by the pulmonary artery catheter-based thermodilution method with a mean bias of 0.109 L/min and limits of agreement from - 1.67 to 1.89 L/min. SVR was also closely correlated (r = 0.86) to traditional catheter-based measurements with a mean bias of 62.1 dyn s/cm5 and limits of agreement from - 260 to 384 dyn s/cm5. Use of diagnostics integrated into therapeutic device function enables the potential for optimizing support to improve outcomes for cardiogenic shock.
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Affiliation(s)
- Steven P Keller
- Institute for Medical Engineering and Science, Massachusetts Institutes of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Brian Y Chang
- Institute for Medical Engineering and Science, Massachusetts Institutes of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Qing Tan
- Abiomed Inc., Danvers, MA, 01923, USA
| | - Zhengyang Zhang
- Institute for Medical Engineering and Science, Massachusetts Institutes of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | | | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institutes of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
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