Pulsatility and flow patterns across macro- and microcirculatory arteries of continuous-flow left ventricular assist device patients

https://doi.org/10.1016/j.healun.2023.04.002Get rights and content

Background

Reduced arterial pulsatility in continuous-flow left ventricular assist devices (CF-LVAD) patients has been implicated in clinical complications. Consequently, recent improvements in clinical outcomes have been attributed to the "artificial pulse" technology inherent to the HeartMate3 (HM3) LVAD. However, the effect of the "artificial pulse" on arterial flow, transmission of pulsatility into the microcirculation and its association with LVAD pump parameters is not known.

Methods

The local flow oscillation (pulsatility index, PI) of common carotid arteries (CCAs), middle cerebral arteries (MCAs) and central retinal arteries (CRAs-representing the microcirculation) were quantified by 2D-aligned, angle-corrected Doppler ultrasound in 148 participants: healthy controls, n = 32; heart failure (HF), n = 43; HeartMate II (HMII), n = 32; HM3, n = 41.

Results

In HM3 patients, 2D-Doppler PI in beats with "artificial pulse" and beats with "continuous-flow" was similar to that of HMII patients across the macro- and microcirculation. Additionally, peak systolic velocity did not differ between HM3 and HMII patients. Transmission of PI into the microcirculation was higher in both HM3 (during the beats with "artificial pulse") and in HMII patients compared with HF patients. LVAD pump speed was inversely associated with microvascular PI in HMII and HM3 (HMII, r2 = 0.51, p < 0.0001; HM3 "continuous-flow," r2 = 0.32, p = 0.0009; HM3 "artificial pulse," r2 = 0.23, p = 0.007), while LVAD pump PI was only associated with microcirculatory PI in HMII patients.

Conclusions

The "artificial pulse" of the HM3 is detectable in the macro- and microcirculation but without creating a significant alteration in PI compared with HMII patients. Increased transmission of pulsatility and the association between pump speed and PI in the microcirculation indicate that the future clinical care of HM3 patients may involve individualized pump settings according to the microcirculatory PI in specific end-organs.

Section snippets

Study population

Four groups of volunteers were enrolled: (1) HF patients, (2) HF patients implanted with the HMII LVAD, (3) HF patients implanted with HM3 LVAD and (4) healthy volunteers. Healthy individuals were included if they did not have any known/diagnosed chronic diseases including hypertension and diabetes, were not taking any regular medication and did not report a current illness. Heart failure patients were included if they were diagnosed with HF for at least 6 months and had a left ventricular

Baseline characteristics

Our final cohort included a total of 148 participants: HF: n = 43; HMII: n = 32; HM3: n = 41; healthy controls: n = 32. Baseline demographics and clinical characteristics are shown in Table 1. INTERMACS profile at the time of LVAD implant did not differ between HMII and HM3 patients. Healthy subjects were younger and had a lower BMI. Pump power, flow, and pulsatility index were higher in HMII than HM3. Due to the consecutive recruitment, duration of LVAD support was longer in HMII compared with

Discussion

Our study provides several novel findings. First, the artificial pulsatility of the HM3 is clearly detectable in the central and medium-sized arteries as well as in the microcirculation. Second, in HM3 patients, the 2D-Doppler PI was higher in beats with "artificial pulse" than in beats with "continuous flow" throughout these vascular compartments; however, although nominally higher, the "artificial pulse" PI of the HM3 was not statistically different from the PI of the HMII. Third,

Disclosure statement

This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 705219. This study was also supported by the Lisa and Mark Schwartz Program to Reverse Heart Failure at New York − Presbyterian Hospital/ Columbia University, NIH grant P30 EY019007 and an unrestricted grant to the Department of Ophthalmology of Columbia University from Research to Prevent Blindness.

The authors have no conflicts of interest

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  • Cited by (0)

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    Now: COR-HELIX (CardiOvascular Regulation and Human Exercise Laboratory – Integration and Xploration), Institute of Sports Science, Leibniz Universität Hannover, 30167 Hannover, Germany

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    Now: Department of Anesthesiology, Yodogawa Christian Hospital, Osaka, Japan

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