Accuracy of Doppler blood pressure measurement in HeartMate 3 ventricular assist device patients

Left Ventricular Assist Device Emergencies: Diagnosis and Management

Durable left ventricular assist devices (LVADs) are a virtually limitless advanced therapy option for an increasingly growing population of patients with end-stage advanced heart failure. As of 2019, 30% to 40% of all patients diagnosed with heart failure were categorized as New York Heart Association class III or IV. In 2018 more than 3.2 million office visits and 1.4 million emergency department visits carried a primary diagnosis of heart failure. Given the rapid growth of the LVAD population, facility in the diagnosis and management of common perioperative and outpatient LVAD emergencies has become of paramount importance in a variety of clinical settings.

Noninvasive finger plethysmography for continuous blood pressure monitoring in patients with left ventricular assist device

BACKGROUND

Accurate blood pressure (BP) measurement remains challenging in patients with HeartMate 3™ left ventricular assist devices (HM3 LVADs). The Finapres® NOVA is a promising non-invasive continuous BP monitor that uses the volume clamp method via a finger cuff, so here we aimed to validate the instrument in HM3 patients.

METHODS

In a single-center cohort, BP was monitored in 15 patients within 72 h following HM3 implantation. A radial artery catheter quantified arterial blood pressure (ABP), while the NOVA measured finger arterial pressure (fiAP) and reconstructed brachial artery pressure (reBAP). Waveforms were recorded for 10 min, and mean values were calculated in 15-s intervals.

RESUTS

fiAP and ABP were moderately correlated during both the first (ICC 0.61, p = 0.04) and final measurements (ICC 0.66, p = 0.03). reBAP and ABP were strongly correlated during both the first (ICC 0.81, p = 0.002) and final measurements (ICC 0.83, p = 0.001). Both NOVA-derived values may underestimate low BP values while overestimating relatively high BP values. The reBAP was within 5 mm Hg of the ABP in 40% of patients (and within 10 mm Hg in 67%).

CONCLUSIONS

This pilot represents the first evidence in support of the Finapres® NOVA for non-invasive BP measurement in select patients with HM3 LVADs. The instrument may provide useful data during BP medication adjustments or pump titration, but despite the correlation between the non-invasive reBAP and invasive ABP, individual-level inaccuracy may be clinically meaningful. Further investigation is needed to clarify these limitations and optimize accuracy before widespread adoption in this unique patient population.

Validity and success rate of noninvasive mean arterial blood pressure measurements in cf-LVAD patients: A technical review

BACKGROUND

The life expectancy of patients with a continuous flow left ventricular assist device (cf-LVAD) is increasing. Adequate determination and regulation of mean arterial pressure (MAP) is important to prevent adverse events. Given the low pulsatility characteristics in these patients, standard blood pressure equipment is inadequate to monitor MAP and not recommended. We provide an overview of currently available noninvasive techniques, using an extensive search strategy in three online databases (Pubmed, Scopus and Google Scholar) to find validation studies using invasive intra-arterial blood pressure measurement as a reference. Mean differences with the reference values smaller than 5 ± 8 mm Hg were considered acceptable.

OBSERVATIONS

After deduplication, screening, and exclusion of incorrect sources, eleven studies remained with 3139 successful MAP measurements in 386 patients. Four noninvasive techniques, using Doppler, pulse oximetry, finger cuff volume clamp, or slow upper arm cuff deflation, were identified and evaluated for validity and success rate in cf-LVAD patients. Here, a comprehensive technical background of the blood pressure measurement methods is provided in combination with a clinical use comparison. Of the reported noninvasive techniques, slow cuff devices performed most optimally (mean difference 1.3 ± 5.2 mm Hg).

CONCLUSIONS

Our results are encouraging and indicate that noninvasive blood pressure monitoring options with acceptable validity and success rate are available. Further technical development and validation is warranted for the growing population of patients on long-term cf-LVAD support.

Low Blood Pressure Threshold for Adverse Outcomes During Left Ventricular Assist Device Support

It has been suggested that maintaining low mean arterial pressure (MAP) in left ventricular assist device (LVAD) recipients is associated with a reduced risk of stroke/death. However, the lower limit of the optimal MAP range has not been established. We aimed to identify this lower limit in a contemporary cohort of LVAD recipients with frequent longitudinal MAP measurements. We analyzed 86,651 MAP measurements in 309 patients with an LVAD (32% LVADs with full magnetic levitation of the impeller) at a tertiary medical center during a mean follow-up of 1.7 ± 1.1 years. Cox proportional hazards regression modeling was used to study the association of serial MAP measurements with stroke/death within 3 years after index discharge. Multivariate analysis identified MAP ≤75 mm Hg, compared with MAP >75 mm Hg, as the low MAP threshold associated with increased risk of death (hazard ratio [HR] 4.74, 95% confidence interval [CI] 2.85 to 7.87, p <0.001), stroke (HR 2.72;, 95% CI 1.39 to 5.33, p = 0.01), and stroke/death (HR 4.45, 95% CI 2.83 to 6.99, p <0.001). The risk associated with MAP ≤75 mm Hg was consistent in subgroups categorized by age, gender, race, device type, renal function, right-sided heart failure, and blood pressure medications. In conclusion, our findings suggest that maintaining MAP ≤75 mm Hg during long-term follow-up in LVAD recipients is associated with increased risk of stroke/death regardless of risk factors or medical management.

Rethinking Rehabilitation: A REVIEW OF PATIENT POPULATIONS WHO CAN BENEFIT FROM CARDIAC REHABILITATION

Although cardiac rehabilitation (CR) is safe and highly effective for individuals with various cardiovascular health conditions, to date there are only seven diagnoses or procedures identified by the Centers for Medicare & Medicaid Services that qualify for referral. When considering the growing number of individuals with cardiovascular disease (CVD), or other health conditions that increase the risk for CVD, it is important to determine the extent for which CR could benefit these populations. Furthermore, there are some patients who may currently be eligible for CR (spontaneous coronary artery dissection, left ventricular assistant device) but make up a relatively small proportion of the populations that are regularly attending and participating. Thus, these patient populations and special considerations for exercise might be less familiar to professionals who are supervising their programs. The purpose of this review is to summarize the current literature surrounding exercise testing and programming among four specific patient populations that either do not currently qualify for (chronic and end-stage renal disease, breast cancer survivor) or who are eligible but less commonly seen in CR (sudden coronary artery dissection, left ventricular assist device). While current evidence suggests that individuals with these health conditions can safely participate in and may benefit from supervised exercise programming, there is an immediate need for high-quality, multisite clinical trials to develop more specific exercise recommendations and support the inclusion of these populations in future CR programs.

Accuracy of Doppler blood pressure measurement in HeartMate 3 ventricular assist device patients

Aims

Optimal blood pressure (BP) control is imperative to reduce complications, especially strokes, in continuous flow ventricular assist device (VAD) patients. Doppler BP has been shown to be an accurate and reliable non‐invasive BP measurement method in HeartMate II and HVAD patients. We examined whether Doppler BP is also accurate in patients with the HeartMate 3 VAD.

Methods and results

In a prospective, longitudinal cohort of HeartMate 3 patients, arterial line BP and simultaneously measured Doppler opening pressure were obtained. Correlation and agreement between Doppler opening pressure and arterial line mean arterial pressure (MAP) versus systolic blood pressure (SBP) were analysed, as well as the effect of pulse pressure on the accuracy of Doppler opening pressure.

A total of 589 pairs of simultaneous Doppler opening pressure and arterial line pressure readings were obtained in 43 patients. Doppler opening pressure had good correlation with intra‐arterial MAP (r = 0.754) and more closely approximated MAP than SBP (mean error 2.0 vs. −8.6 mmHg). Pulse pressure did not have a clinically significant impact on the accuracy of the Doppler BP method. These results in HeartMate 3 patients are very similar to previous results in HeartMate II and HVAD patients.

Conclusions

Doppler BP method should be the default non‐invasive BP measurement method in continuous flow VAD patients including patients implanted with the HeartMate 3.