Phenotyping of Stable Left Ventricular Assist Device Patients Using Noninvasive Pump Flow Responses to Acute Loading Transients

doi:10.1016/j.cardfail.2021.01.009

Journal of Cardiac Failure

Volume 27, Issue 6, June 2021, Pages 642-650

https://doi.org/10.1016/j.cardfail.2021.01.009 Get rights and content

Abstract

Background

Although it has been established that continuous flow left ventricular assist devices are sensitive to loading conditions, the effect of acute load and postural changes on pump flow have not been explored systematically.

Methods and Results

Fifteen stable outpatients were studied. Patients sequentially transitioned from the seated position to supine, passive leg raise, and standing with transition effects documented. A modified Valsalva maneuver, consisting of a forced expiration with an open glottis, was performed in each position. A sustained, 2-handed handgrip was performed in the supine position. The pump flow waveform was recorded continuously and left ventricular end-diastolic diameter measured during each stage using transthoracic echocardiography. Transitioning from seated to supine posture produced a significant increase in the flow and the ventricular end-diastolic diameter, consistent with an increased preload. The transition from supine to standing produced a transient increase in the mean flow and decreased the flow pulsatility index. At steady state, these changes were reversed with a decrease in the mean and trough flow and increased pulsatility index, consistent with venous redistribution and possible baroreflex compensation. Four distinct patterns of standing-induced flow waveform effects were identified, reflecting varying preload, afterload, and individual compensatory effects. A sustained handgrip produced a significant decrease in flow and increase in flow pulsatility across all patients, reflecting an increased afterload pressure. A modified Valsalva maneuver produced a decrease in the flow pulsatility while seated, supine, and standing, but not during leg raise. Five patterns of pulsatility effect during Valsalva were observed: (1) minimal change, (2) pulsatility recovery, (3) rapid flatline, (4) slow flatline with delayed flow recovery, and (5) primary suction.

Conclusions

Acute disturbances in loading conditions produce heterogeneous pump flow responses reflecting their complex interactions with pump and ventricular function as well as reflex compensatory mechanisms. Differences in responses and individual variabilities have significant implications for automated pump control algorithms.

Section snippets

Methods

After obtaining informed consent, stable outpatients supported with the HeartWare HVAD (Medtronic LLC, Minneapolis, MN) were studied. Pump flow waveforms were recorded continuously at 50Hz using proprietary software (Medical University of Vienna, Vienna, Austria). Patients sequentially transitioned from the seated position to supine, passive leg raise and standing. Sustained, maximal 2-handed handgrip was performed in the supine position. Transitions between stages were defined as the first 5

Results

Fifteen patients were studied, with baseline characteristics outlined in Table 1. Steady-state measurements are displayed in Fig. 1 and transition measurements in Fig. 2, with all postural data presented in Supplementary Table S1. Transitioning from seated to supine posture produced a transient, significant increase in flow (4.3 ± 0.9 L/min vs 5.1 ± 1.0 L/min, P < .0001), consistent with increased preload, and persisting to a diminished degree at steady state (4.8 ± 0.9 L/min, P = .0002 vs

Discussion

It has been demonstrated in silico that pump flow varies in a predictable fashion according to isolated changes in loading conditions and ventricular contractility, and this variation can potentially provide insights into patient hemodynamics.⁶^,⁹ However, use of the flow waveform in vivo is complicated by a constant interplay between loading conditions, ventricular performance, pump function, and compensatory mechanisms.¹⁰ This study is the first to assess these interactions systematically,

Conclusions

Dynamic maneuvers can have dramatic effects on the pump flow waveform via changes in loading conditions and secondary compensatory responses. Assessment of these effects may allow more individualized, patient-centered care. Automated pump speed algorithms must account for the wide variability in responses across different patients.

Disclosures

Professor Hayward: Medtronic - Speakers' Bureau, Consultancy to individual, Research grant to Hospital, Patent Holder (owned by hospital, Licenced by Medtronic). There are no other relevant disclosures.

References (21)

UP Jorde et al.
Results of the destination therapy post-food and drug administration approval study with a continuous flow left ventricular assist device: a prospective study using the INTERMACS registry (Interagency Registry for Mechanically Assisted Circulatory Support)
J Am Coll Cardiol
(2014)
CA Milano et al.
HVAD: the ENDURANCE Supplemental Trial
JACC Heart Fail
(2018)
P Jain et al.
Dynamic flow responses to expiratory maneuvers in left ventricular assist device patients
J Heart Lung Transplant
(2019)
K Addetia et al.
3D morphological changes in LV and RV during LVAD ramp studies
JACC Cardiovasc Imaging
(2018)
MR Mehra et al.
A fully magnetically levitated left ventricular assist device - final report
N Engl J Med
(2019)
JG Rogers et al.
Intrapericardial left ventricular assist device for advanced heart failure
N Engl J Med
(2017)
J Stehlik et al.
Patient-reported health-related quality of life is a predictor of outcomes in ambulatory heart failure patients treated with left ventricular assist device compared with medical management: results from the ROADMAP Study (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management)
Circ Heart Fail
(2017)
Muthiah K, Gupta S, Otton J, Robson D, Walker R, Tay A, et al. Body position and activity, but not heart rate, affect...
RF Salamonsen et al.
Response of rotary blood pumps to changes in preload and afterload at a fixed speed setting are unphysiological when compared with the natural heart
Artif Organs
(2011)
R Clifford et al.
Beat-to-beat detection of aortic valve opening in HeartWare left ventricular assist device patients
Artif Organs
(2019)

There are more references available in the full text version of this article.

Cited by (4)

HeartMate 3 Snoopy: Noninvasive cardiovascular diagnosis of patients with fully magnetically levitated blood pumps during echocardiographic speed ramp tests and Valsalva maneuvers
2024, Journal of Heart and Lung Transplantation
The HeartMate 3 (HM3) left ventricular assist device (LVAD) has demonstrated excellent clinical outcomes; however, pump speed optimization is challenging with the available HM3 monitoring. Therefore, this study reports on clinical HM3 parameters collected with a noninvasive HM3 monitoring system (HM3 Snoopy) during echocardiographic speed ramp tests and Valsalva maneuvers.
In this prospective, single-center study, the HM3 data communication between the controller and pump was recorded with a novel data acquisition system. Twelve pump parameters sampled every second (1 Hz) and clinical assessments (echocardiography, electrocardiogram (ECG), and blood pressure measurement) during speed ramp tests were analyzed using Pearson’s correlation (r, median [IQR]). The cause for the occurrence of pulsatility index (PI)-events during ramp speed tests and valsalva maneuvers was investigated.
In 24 patients (age: 58.9 ± 8.8 years, body mass index: 28.1 ± 5.1 kg/m², female: 20.8%), 35 speed ramp tests were performed with speed changes in the range of ±1000 rpm from a baseline speed of 5443 ± 244 rpm. Eight HM3 pump parameters from estimated flow, motor current, and LVAD speed together with blood pressure showed positive collinearities (r = 0.9 [0.1]). Negative collinearities were observed for pump flow pulsatility, pulsatility index, rotor noise, and left ventricular diameters (r = −0.8 [0.1]), whereas rotor displacement and heartrate showed absence of collinearities (r = −0.1 [0.08]).
In this study, the HM3 Snoopy was successfully used to acquire more parameters from the HM3 at a higher sampling rate. Analysis of HM3 per-second data provide additional clinical diagnostic information on heart-pump interactions and cause of PI-events.
Global best practices consensus: Long-term management of patients with hybrid centrifugal flow left ventricular assist device support
2022, Journal of Thoracic and Cardiovascular Surgery
Citation Excerpt :
As shown in Figure 1, different portions of the flow waveform can be examined to assess each of these aspects of cardiac and vascular function.33 The importance of changes in physiological conditions contributing dynamic changes in the pump flow waveform can be in response to position,31 and physiological intervention such as straining, or Valsalva maneuver.34,35 Three immediately useful waveform characteristics to recognize are flow pulsatility (peak flow minus trough flow), evidence of ventricular suction, and changes associated with systemic hypertension because each of these can rapidly direct therapy (Figure 2).
Six months after withdrawal of the HeartWare HVAD System (HVAD; Medtronic) from sale, approximately 4000 patients continue ongoing support with this device. In light of the diminishing experience, this global consensus document summarizes key management recommendations.
International experts with experience in the management of patients with ongoing HVAD support were invited to summarize key aspects of patient and pump management and highlight differences in the current HeartMate 3 (Abbott Laboratories) ventricular assist device. Clinicians from high-implanting HVAD sites reviewed current literature and reported experience to generate a consensus statement.
Specific guidelines to assist in the management of ongoing HVAD patients are developed. Key management protocols and helpful techniques developed from experienced clinicians are combined into a short guideline document. As experience with HeartMate 3 increases, key differences in approach to management are highlighted, where appropriate.
With decreasing worldwide experience in the ongoing management of HVAD-supported patients, this consensus guideline provides a summary of best practice techniques from international centers. Differences in HeartMate 3 management are highlighted.
Using pulsatility responses to breath-hold maneuvers to predict readmission rates in continuous-flow left ventricular assist device patients
2024, Artificial Organs
A Sensorless Modular Multiobjective Control Algorithm for Left Ventricular Assist Devices: A Clinical Pilot Study
2022, Frontiers in Cardiovascular Medicine

View full text

Phenotyping of Stable Left Ventricular Assist Device Patients Using Noninvasive Pump Flow Responses to Acute Loading Transients

Abstract

Background

Methods and Results

Conclusions

Section snippets

Methods

Results

Discussion

Conclusions

Disclosures

J Am Coll Cardiol

JACC Heart Fail

J Heart Lung Transplant

JACC Cardiovasc Imaging

A fully magnetically levitated left ventricular assist device - final report

N Engl J Med

Intrapericardial left ventricular assist device for advanced heart failure

N Engl J Med

Circ Heart Fail

Response of rotary blood pumps to changes in preload and afterload at a fixed speed setting are unphysiological when compared with the natural heart

Artif Organs

Beat-to-beat detection of aortic valve opening in HeartWare left ventricular assist device patients

Artif Organs