scholarly journals Hysteretic device characteristics indicate cardiac contractile state for guiding mechanical circulatory support device use

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Brian Y. Chang ◽  
Zhengyang Zhang ◽  
Kimberly Feng ◽  
Noam Josephy ◽  
Steven P. Keller ◽  
...  
Keyword(s):  
Heart Failure ◽  
Hysteresis Loop ◽  
Mechanical Circulatory Support ◽  
Animal Studies ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Circulatory Support ◽  
Continuous Measure ◽  
Stroke Work ◽  
Maximum Slope

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.

P5735Feasibility and safety of Impella mechanical circulatory support in different clinical scenarios: a single-centre experience

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
C Marini ◽  
V Pazzanese ◽  
M Pagnesi ◽  
M Gramegna ◽  
L F Bertoldi ◽  
...  
Keyword(s):  
Heart Failure ◽  
High Risk ◽  
Mechanical Circulatory Support ◽  
Myocardial Revascularization ◽  
Limb Ischemia ◽  
Left Ventricular ◽  
Circulatory Support ◽  
Acute Limb Ischemia ◽  
Stroke Work ◽  
Hemodynamic Support

Abstract Background The Impella (Abiomed, Danvers, MA) mechanical circulatory support is a catheter-based axial-flow pump. It reduces left ventricular (LV) stroke work and myocardial oxygen demand while increasing systemic and coronary perfusion in the setting of cardiogenic shock (CS), and it provides hemodynamic support during high-risk percutaneous coronary intervention (PCI). Purpose To evaluate the outcomes of Impella-supported patients in the context of CS and protected-PCI. Methods This single-center registry includes all patients implanted with Impella device at our institution between February 2013 and June 2018. Indications for Impella support were CS (hypotension despite adequate filling status with signs of hypoperfusion) and protected-PCI (prophylactic hemodynamic support during non-emergent high-risk PCI). Results A total of 145 patients were implanted with Impella: 130 (89.7%) for CS and 15 (10.3%) for protected-PCI. Among CS patients, mean age was 61.6±12.9, 79.2% males. The prevalence of chronic heart failure (HF) was 26.1%, prior myocardial infarction (MI) 29% and myocardial revascularization 36.6%, chronic kidney disease (CKD) 18.3%. Among protected PCI patients, mean age was 73.4±8.7 years, 86.7% males. The prevalence of HF was 85.7%, prior MI 42.9%, myocardial revascularization 35.7%, CKD 57.1%. In CS group, the indications for Impella implantation were myocarditis in 8 (6.2%) patients, acute coronary syndromes in 77 (59.2%), periprocedural ventricular tachycardia ablation CS in 10 (7.7%), decompensated heart failure in 26.9%. Out of hospital cardiac arrest occurred in 35 (30.4%) patients, INTERMACS I class in 70 (59.3%), mean arterial pressure was 65.4±18.4 mmHg, serum lactate 6.7±5.5 mmol/l, at least 1 inotropic agent use in 73 (66.4%), mean LV EF 21.4±11,7%, right ventricular dysfunction in 53 (48.6%). The rate of device-related complications was not negligible in CS group: 18 (14.5%) patients had limb ischemia and vascular surgery was required in 14, 17 (14.3%) had access-site bleeding. A total of 42 (33.3%) had haemolysis, and 67 (56.8%) acute kidney injury (AKI), half of whom requiring renal replacement therapy. Escalation to other therapies was necessary in 43 cases. Conversely, in the protected-PCI group a low rate of AKI (n=4, 28.6%) and acute limb ischemia (n=1, 7.1%) was observed, whereas no cases of haemolysis nor need of escalation therapy were recorded. Mean Impella support was 135.5±167.21 days for CS group, 60.6±80 for protected-PCI group. Survival at 30 days was 60.33% for CS group and 92.9% for protected-PCI group. One-year all-cause death was 50% for CS group and 13.3% for protected-PCI group. Conclusion Mechanical circulatory support with Impella is associated with good outcomes and reasonable rates of complications in the protected-PCI group, whereas less favorable results were observed in CS population probably due to the greater severity of clinical presentation.

scholarly journals Can mechanical circulatory support be an effective treatment for HFpEF patients?

2021 ◽  
Author(s):  
Einar Gude ◽  
Arnt E. Fiane
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Mechanical Circulatory Support ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Cavity ◽  
Circulatory Support ◽  
Left Ventricular Assist Devices ◽  
Mechanical Pressure ◽  
Entry Points

AbstractHeart failure with preserved ejection fraction (HFpEF) is increasing in prevalence and represents approximately 50% of all heart failure (HF) patients. Patients with this complex clinical scenario, characterized by high filling pressures, and reduced cardiac output (CO) associated with progressive multi-organ involvement, have so far not experienced any significant improvement in quality of life or survival with traditional HF treatment. Left ventricular assist devices (LVAD) have offered a new treatment alternative in terminal heart failure patients with reduced ejection fraction (HFrEF), providing a unique combination of significant pressure and volume unloading together with an increase in CO. The small left ventricular cavity in HFpEF patients challenges left-sided pressure unloading, and new anatomical entry points need to be explored for mechanical pressure and volume unloading. Optimized and pressure/volume-adjusted mechanical circulatory support (MCS) devices for HFrEF patients may conceivably be customized for HFpEF anatomy and hemodynamics. We have developed a long-term MCS device for HFpEF patients with atrial unloading in a pulsed algorithm, leading to a significant reduction of filling pressure, maintenance of pulse pressure, and increase in CO demonstrated in animal testing. In this article, we will discuss HFpEF pathology, hemodynamics, and the principles behind our novel MCS device that may improve symptoms and prognosis in HFpEF patients. Data from mock-loop hemolysis studies, acute, and chronic animal studies will be presented.

scholarly journals Altered LV inotropic reserve and mechanoenergetics early in the development of heart failure

2000 ◽  
Vol 278 (3) ◽  
pp. H698-H705 ◽  
Author(s):  
Sumanth D. Prabhu ◽  
Gregory L. Freeman
Keyword(s):  
Heart Failure ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Stroke Work ◽  
Short Term ◽  
Before And After ◽  
Autonomic Blockade ◽  
Anesthetized Dogs ◽  
Rapid Ventricular Pacing ◽  
Volume Relation

To test the hypothesis that alterations in left ventricular (LV) mechanoenergetics and the LV inotropic response to afterload manifest early in the evolution of heart failure, we examined six anesthetized dogs instrumented with LV micromanometers, piezoelectric crystals, and coronary sinus catheters before and after 24 h of rapid ventricular pacing (RVP). After autonomic blockade, the end-systolic pressure-volume relation (ESPVR), myocardial O2 consumption (MV˙o 2), and LV pressure-volume area (PVA) were defined at several different afterloads produced by graded infusions of phenylephrine. Short-term RVP resulted in reduced preload with proportionate reductions in stroke work and the maximum first derivative of LV pressure but with no significant reduction in baseline LV contractile state. In response to increased afterload, the baseline ESPVR shifted to the left with maintained end-systolic elastance ( E es). In contrast, after short-term RVP, in response to comparable increases in afterload, the ESPVR displayed reduced E es ( P < 0.05) and significantly less leftward shift compared with control ( P< 0.05). Compared with the control MV˙o 2-PVA relation, short-term RVP significantly increased the MV˙o 2 intercept ( P< 0.05) with no change in slope. These results indicate that short-term RVP produces attenuation of afterload-induced enhancement of LV performance and increases energy consumption for nonmechanical processes with maintenance of contractile efficiency, suggesting that early in the development of tachycardia heart failure, there is blunting of length-dependent activation and increased O2requirements for excitation-contraction coupling, basal metabolism, or both. Rather than being adaptive mechanisms, these abnormalities may be primary defects involved in the progression of the heart failure phenotype.

Left ventricular spherical dilation and regional contractile dysfunction in dogs with heart failure

1997 ◽  
Vol 273 (3) ◽  
pp. H1058-H1067 ◽  
Author(s):  
M. Suzuki ◽  
C. P. Cheng ◽  
N. Ohte ◽  
W. C. Little
Keyword(s):  
Heart Failure ◽  
Structural Changes ◽  
Contractile Function ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Stroke Work ◽  
End Diastolic Volume ◽  
Work Area ◽  
Rv Pacing ◽  
Volume Relation

Left ventricular (LV) short- and long-axis contractile function and LV structural changes were serially measured in eight instrumented dogs during the development of congestive heart failure (CHF) induced by rapid right ventricular (RV) pacing. After 10 days of pacing, LV end-diastolic volume (VED) had not increased; however, the slope of LV end-systolic pressure-volume relation had decreased from 7.4 +/- 2.6 to 4.9 +/- 1.1 mmHg/ml (P < 0.05), and the slope of LV stroke work-VED relation had fallen from 78.4 +/- 9.1 to 64.2 +/- 7.2 mmHg (P < 0.05). The slopes of end-systolic pressure-dimension relation and the stroke work area-end-diastolic dimension relation in the short axes (i.e., anteroposterior and septal-lateral) had decreased by 30% (P < 0.05), whereas the slopes of the long-axis (i.e., apical-basal) relations were unchanged (not significant). After 20 days of pacing, VED had significantly increased by 14% due to selective dilation of the short axes by 7%, and LV global contractility had further declined with a 40% contractile depression in the short axes and a 25% contractile depression in the long axis. After 30 days, the long-axis dimension at end diastole was also significantly increased with a further increase in the short-axis dimensions. In contrast to the spherical dilation occurring during CHF, acute volume loading of normal animals produced symmetrical LV dilation. These observations suggest that heterogeneous contractile depression initiates the spherical end-diastolic chamber dilation in pacing-induced CHF.

scholarly journals Hemodynamic Adaptation of Heart Failure to Percutaneous Venoarterial Extracorporeal Circulatory Supports

2020 ◽  
pp. 739-757
Author(s):  
P Hála ◽  
O Kittnar
Keyword(s):  
Heart Failure ◽  
Life Support ◽  
Extracorporeal Life Support ◽  
High Volume ◽  
Left Ventricular ◽  
Circulatory Support ◽  
Stroke Work ◽  
Atrial Septostomy ◽  
Active Venting ◽  
Myocardial Oxygen Supply

Extracorporeal life support (ECLS) is a treatment modality that provides prolonged blood circulation, gas exchange and can partially support or fully substitute functions of heart and lungs in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Due to high-volume bypass, the extracorporeal flow is interacting with native cardiac output. The pathophysiology of circulation and ECLS support reveals significant effects on arterial pressure waveforms, cardiac hemodynamics, and myocardial perfusion. Moreover, it is still subject of research, whether increasing stroke work caused by the extracorporeal flow is accompanied by adequate myocardial oxygen supply. The left ventricular (LV) pressure-volume mechanics are reflecting perfusion and loading conditions and these changes are dependent on the degree of the extracorporeal blood flow. By increasing the afterload, artificial circulation puts higher demands on heart work with increasing myocardial oxygen consumption. Further, this can lead to LV distention, pulmonary edema, and progression of heart failure. Multiple methods of LV decompression (atrial septostomy, active venting, intra-aortic balloon pump, pulsatility of flow) have been suggested to relieve LV overload but the main risk factors still remain unclear. In this context, it has been recommended to keep the rate of circulatory support as low as possible. Also, utilization of detailed hemodynamic monitoring has been suggested in order to avoid possible harm from excessive extracorporeal flow.

scholarly journals Clinical Outcomes Associated with Acute Mechanical Circulatory Support Utilization in Heart Failure Related Cardiogenic Shock

2021 ◽  
Author(s):  
Jaime Hernandez-Montfort ◽  
Shashank S. Sinha ◽  
Katherine L. Thayer ◽  
Evan H. Whitehead ◽  
Mohit Pahuja ◽  
...  
Keyword(s):  
Heart Failure ◽  
Hospital Mortality ◽  
Cardiogenic Shock ◽  
Clinical Outcomes ◽  
Mechanical Circulatory Support ◽  
Left Ventricular ◽  
Right Atrial ◽  
Circulatory Support ◽  
Hospital Death ◽  
Acute Mechanical Circulatory Support

Background : Cardiogenic shock occurring in the setting of advanced heart failure (HF-CS) is increasingly common. However, recent studies have focused almost exclusively on acute myocardial infarction related cardiogenic shock. We sought to define clinical, hemodynamic, metabolic, and treatment parameters associated with clinical outcomes among HF-CS patients, using data from the Cardiogenic Shock Working Group (CSWG) Registry. Methods : Patients with HF-CS were identified from the multi-center CSWG registry and divided into 3 outcome categories assessed at hospital discharge: mortality, heart replacement therapy (HRT: durable ventricular assist device [VAD] or orthotopic heart transplant [OHT]), or native heart survival (NHS). Clinical characteristics, hemodynamic, laboratory parameters, drug therapies, acute mechanical circulatory support device (AMCS) utilization, and Society of Cardiovascular Angiography and Intervention (SCAI) stages were compared across the 3 outcome cohorts. Results : Of the 712 HF-CS patients identified, 180 (25.3%) died during their index admission, 277 (38.9%) underwent HRT (durable VAD or OHT), and 255 (35.8%) experienced NHS without HRT. Patients who died had the highest right atrial pressure and heart rate and the lowest mean arterial pressure of the 3 outcome groups (p<0.01 for all). Biventricular and isolated left-ventricular congestion were common among patients who died or underwent HRT, respectively. Lactate, blood urea nitrogen, serum creatinine, and aspartate aminotransferase were highest in HF-CS patients experiencing in-hospital death. Intra-aortic balloon pump (IABP) was the most commonly used AMCS device in the overall cohort and among patients receiving HRT. Patients receiving more than one AMCS device had the highest in-hospital mortality rate irrespective of the number of vasoactive drugs used. Mortality decreased with deteriorating SCAI stages (stage B: 0%, stage C: 10.7%, stage D: 29.4%, stage E: 54.5%, 1-way ANOVA = <0.001). Conclusions : Patients with HF-CS experiencing in-hospital mortality had a high prevalence of biventricular congestion and markers of end-organ hypoperfusion. Substantial heterogeneity exists with use of AMCS in HF-CS with IABP being the most common device used and high rates of in-hospital mortality after exposure to more than one AMCS device.

Abstract 14613: Preclinical Animal Model of Doxorubicin-induced Left Ventricular Dysfunction: Echocardiography and Pressure-volume Analysis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Petr Kala ◽  
Zuzana Honetschlagerova ◽  
Zuzana Huskova ◽  
Zdenka Vanourkova ◽  
Petra Škaroupková ◽  
...  
Keyword(s):  
Heart Failure ◽  
Animal Model ◽  
Left Ventricle ◽  
Left Ventricular Dysfunction ◽  
Ventricular Dysfunction ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Stroke Work ◽  
Cardiac Efficiency ◽  
Volume Analysis

Introduction: There is a need to implement a preclinical model in addition to the well established ischemic or volume-overload models that would mimic the clinical course of patients with chemotherapy-induced heart failure. Doxorubicin is an anthracycline chemotherapeutic that is widely used in oncology, although its cardiotoxicity. Hypothesis: Doxorubicin-induced left ventricular dysfunction in rats fulfills echocardiography and hemodynamic characteristics of chemotherapy-induced heart failure. Methods: We randomly assigned Ren-2 transgenic hypertensive (TGR, n = 17) and normotensive rats (HanSD, n = 22), at the age of 8 weeks to doxorubicin (2.5 mg/kg in 0.5 ml of normal saline) or placebo in 6 intraperitoneal doses within two weeks (cumulative doxorubicin dose 15 mg/kg). Two weeks later, we performed echocardiography study, pressure-volume analysis (PV), and we weighed the organs. Results: In doxorubicin groups, there was a decrease in the left ventricle weight (1,22 vs. 0,85 g in TGR), while an increase in wall stress (22036 vs. 29754 μL*mmHg/g in TGR). Echocardiography suggested heart remodeling with a decrease in relative wall thickness - RWT (1.02 vs. 0.65 mm in TGR), and together with PV analysis showed a decrease in systolic parameters - left ventricle ejection fraction - LVEF (71.41 vs. 59.96 % in TGR), end-systolic pressure-volume ratio - ESPVR (0.82 vs. 0.45 mmHg/uL in TGR) and preload recruitable stroke work - PRSW (75.71 vs. 60.98 mmHg in TGR). Ventricular-arterial coupling (VAC = Ea/Ees, a measure of cardiac efficiency) was worsened in the doxorubicin groups (1.69 vs. 2.52 in TGR). For all the above p < 0.05, in HanSD, the results were similar (all p < 0.05). Conclusions: Our results suggest that systolic dysfunction and decrease of cardiac efficiency in this model could be caused by heart atrophy, and such an animal model could potentially be an easily reproducible model of chemotherapy-induced heart failure in preclinical cardio-oncology studies.

scholarly journals Muscle metaboreflex-induced increases in effective arterial elastance: effect of heart failure

2020 ◽  
Vol 319 (1) ◽  
pp. R1-R10 ◽  
Author(s):  
Joseph Mannozzi ◽  
Jasdeep Kaur ◽  
Marty D. Spranger ◽  
Mohamed-Hussein Al-Hassan ◽  
Beruk Lessanework ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Dynamic Exercise ◽  
Stroke Work ◽  
Arterial Elastance ◽  
Muscle Metaboreflex ◽  
Effective Arterial Elastance

Dynamic exercise elicits robust increases in sympathetic activity in part due to muscle metaboreflex activation (MMA), a pressor response triggered by activation of skeletal muscle afferents. MMA during dynamic exercise increases arterial pressure by increasing cardiac output via increases in heart rate, ventricular contractility, and central blood volume mobilization. In heart failure, ventricular function is compromised, and MMA elicits peripheral vasoconstriction. Ventricular-vascular coupling reflects the efficiency of energy transfer from the left ventricle to the systemic circulation and is calculated as the ratio of effective arterial elastance ( Ea) to left ventricular maximal elastance ( Emax). The effect of MMA on Ea in normal subjects is unknown. Furthermore, whether muscle metaboreflex control of Ea is altered in heart failure has not been investigated. We utilized two previously published methods of evaluating Ea [end-systolic pressure/stroke volume ( EaPV)] and [heart rate × vascular resistance ( EaZ)] during rest, mild treadmill exercise, and MMA (induced via partial reductions in hindlimb blood flow imposed during exercise) in chronically instrumented conscious canines before and after induction of heart failure via rapid ventricular pacing. In healthy animals, MMA elicits significant increases in effective arterial elastance and stroke work that likely maintains ventricular-vascular coupling. In heart failure, Ea is high, and MMA-induced increases are exaggerated, which further exacerbates the already uncoupled ventricular-vascular relationship, which likely contributes to the impaired ability to raise stroke work and cardiac output during exercise in heart failure.

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