Initial experience with telemonitoring in left ventricular assist device patients

Monitoring left ventricular assist device parameters to detect flow- and power-impacting complications: a proof of concept

Aims

The number of patients on left ventricular assist device (LVAD) support increases due to the growing number of patients with end-stage heart failure and the limited number of donor hearts. Despite improving survival rates, patients frequently suffer from adverse events such as cardiac arrhythmia and major bleeding. Telemonitoring is a potentially powerful tool to early detect deteriorations and may further improve outcome after LVAD implantation. Hence, we developed a personalized algorithm to remotely monitor HeartMate3 (HM3) pump parameters aiming to early detect unscheduled admissions due to cardiac arrhythmia or major bleeding.

Methods and results

The source code of the algorithm is published in an open repository. The algorithm was optimized and tested retrospectively using HeartMate 3 (HM3) power and flow data of 120 patients, including 29 admissions due to cardiac arrhythmia and 14 admissions due to major bleeding. Using a true alarm window of 14 days prior to the admission date, the algorithm detected 59 and 79% of unscheduled admissions due to cardiac arrhythmia and major bleeding, respectively, with a false alarm rate of 2%.

Conclusion

The proposed algorithm showed that the personalized algorithm is a viable approach to early identify cardiac arrhythmia and major bleeding by monitoring HM3 pump parameters. External validation is needed and integration with other clinical parameters could potentially improve the predictive value. In addition, the algorithm can be further enhanced using continuous data.

Estimation of Left Ventricular Stroke Work for Rotary Left Ventricular Assist Devices

Continuous monitoring of left ventricular stroke work (LVSW) may improve the medical management of patients with rotary left ventricular assist devices (LVAD). However, implantable pressure-volume sensors are limited by measurement drift and hemocompatibility. Instead, estimator algorithms derived from rotary LVAD signals may be a suitable alternative. An LVSW estimator algorithm was developed and evaluated in a range of in vitro and ex vivo cardiovascular conditions during full assist (closed aortic valve [AoV]) and partial assist (opening AoV) mode. For full assist, the LVSW estimator algorithm was based on LVAD flow, speed, and pump pressure head, whereas for partial assist, the LVSW estimator combined the full assist algorithm with an estimate of AoV flow. During full assist, the LVSW estimator demonstrated a good fit in vitro and ex vivo (R 2 : 0.97 and 0.86, respectively) with errors of ± 0.07 J. However, LVSW estimator performance was reduced during partial assist, with in vitro : R 2 : 0.88 and an error of ± 0.16 J and ex vivo : R 2 : 0.48 with errors of ± 0.11 J. Further investigations are required to improve the LVSW estimate with partial assist; however, this study demonstrated promising results for a continuous estimate of LVSW for rotary LVADs.

Coronavirus disease 2019 and cardiovascular disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus behind the coronavirus disease 2019 (COVID-19) pandemic, is a type of RNA virus that is nonsegmented. Cardiovascular diseases (CVDs) increase the mortality risk of patients. In this review article, we overview the existing evidence regarding the potential mechanisms of myocardial damage in coronavirus disease 2019 (COVID-19) patients. Having a comprehensive knowledge of the cardiovascular damage caused by SARS-CoV-2 and its underlying mechanisms is essential for providing prompt and efficient treatment, ultimately leading to a reduction in mortality rates. Severe COVID-19 causes acute respiratory distress syndrome and shock in patients. In addition, awareness regarding COVID-19 cardiovascular manifestations has increased, including the adverse impact on prognosis with cardiovascular involvement. Angiotensin-converting enzyme 2 receptor may play a role in acute myocardial injury caused by SARS-CoV-2 infection. COVID-19 patients experiencing heart failure may have their condition exacerbated by various contributing factors and mechanisms. Increased oxygen demand, myocarditis, stress cardiomyopathy, elevated pulmonary pressures, and venous thrombosis are potential health issues. The combination of these factors may lead to COVID-19-related cardiogenic shock, resulting in acute systolic heart failure. Extracorporeal membrane oxygenation (ECMO) and left ventricular assist devices (LVADs) are treatment options when inotropic support fails for effective circulatory support. To ensure effective COVID-19-related cardiovascular disease (CVD) surveillance, it is crucial to closely monitor the future host adaptation, viral evolution, and transmissibility of SARS-CoV-2, given the virus's pandemic potential.

Coronavirus disease 2019 and mechanical circulatory support devices: A comprehensive review

Coronavirus disease (COVID-19) can cause circulatory shock refractory to medical therapy. Such patients can be managed with mechanical circulatory support (MCS) devices like IABP, Impella, VA ECMO, and Left Ventricular Assist Devices (LVADs). Moreover, patients on long-term durable LVADs are a special population having increased susceptibility and mortality to COVID-19 infection. In this narrative review, we searched PubMed and Medline for studies on COVID-19 patients on short-term MCS devices. We found 36 papers with 110 patients who met our review criteria, including 89 LVAD patients and 21 COVID-19 patients who needed MCS device therapy. These studies were used to extract patient demographics, clinical presentation, MCS device details, management, and outcomes. Mean age of patients with COVID-19 infection on LVADs was 60, 73% were male, and HeartMate 3 was the most common device (53%). Most patients (77.5%) needed hospitalization, and mortality was 23.6%. Among the 21 reported cases of critically ill COVID-19 patients who required MCS, the mean age was 49.8 years, 52% were women, and the most common MCS device used was VA ECMO (62%) in conjunction with an Impella for LV venting. Comorbidities were not present in 43%, but 71% had abnormal ventricular function on echocardiography. MCS is a viable option for managing severe COVID-19 infection with shock, with many reported cases of favorable outcomes.

Validation of Intrinsic Left Ventricular Assist Device Data Tracking Algorithm for Early Recognition of Centrifugal Flow Pump Thrombosis

Advanced stage heart failure patients can benefit from the unloading effects of an implantable left ventricular assist device. Despite best clinical practice, LVADs are associated with adverse events, such as pump thrombosis (PT). An adaptive algorithm alerting when an individual’s appropriate levels in pump power uptake are exceeded, such as in the case of PT, can improve therapy of patients implanted with a centrifugal LVAD. We retrospectively studied 75 patients implanted with a centrifugal LVAD in a single center. A previously optimized adaptive pump power-tracking algorithm was compared to clinical best practice and clinically available constant threshold algorithms. Algorithm performances were analyzed in a PT group (n = 16 patients with 30 PT events) and a thoroughly selected control group (n = 59 patients, 34.7 patient years of LVAD data). Comparison of the adaptive power-tracking algorithm with the best performing constant threshold algorithm resulted in sensitivity of 83.3% vs. 86.7% and specificity of 98.9% vs. 95.3%, respectively. The power-tracking algorithm produced one false positive detection every 11.6 patient years and early warnings with a median of 3.6 days prior to PT diagnosis. In conclusion, a retrospective single-center validation study with real-world patient data demonstrated advantageous application of a power-tracking algorithm into LVAD systems and clinical practice.

Treatment of Advanced Heart Failure-Focus on Transplantation and Durable Mechanical Circulatory Support: What Does the Future Hold?

Heart transplantation (HTx) is the treatment of choice in patients with late-stage advanced heart failure (Advanced HF). Survival rates 1, 5, and 10 years after transplantation are 87%, 77%, and 57%, respectively, and the average life expectancy is 9.16 years. However, because of the donor organ shortage, waiting times often exceed life expectancy, resulting in a waiting list mortality of around 20%. This review aims to provide an overview of current standard, recent advances, and future developments in the treatment of Advanced HF with a focus on long-term mechanical circulatory support and HTx.

A pilot clinical trial of a self-management intervention in patients with a left ventricular assist device

Self-management is a health behavior known to predict treatment outcomes in patients with multiple co-morbidities and/or chronic conditions. However, the self-management process and outcomes in the left-ventricular assist device (LVAD) population are understudied. This pilot randomized control trial (RCT) evaluated the feasibility of a novel "smartphone app-directed and nurse-supported self-management intervention" in patients implanted with durable LVADs. Assessments included behavioral (self-efficacy and adherence), clinical (complications), and healthcare utilization (unplanned clinic, emergency room (ER) visits, and re-hospitalization) outcomes, completed at baseline (pre-hospital discharge) and months 1, 3, and 6 post-hospital discharge. Intervention patients (n = 14) had favorable patterns/trends of results across study outcomes than control patients (n = 16). Notably, intervention patients had much lower complications and healthcare utilization rates than controls. For example, intervention patients had 2 (14.3%) driveline infections in 6 months while control patients had 3 (19.0%). Additionally, at month 3, intervention patients had 0% ER visits versus 36% of control patients. At month 6, the mean cumulative number of re-hospitalizations for the control group was higher (0.9 ± 0.93) than intervention (0.3 ± 0.61) group. Despite the small sample size and limitations of feasibility/pilot studies, our outcomes data appeared to favor the novel intervention. Lessons learned from this study suggest the intervention should be implemented for 6 months post-hospital discharge. Further research is needed including large and rigorous multi-center RCTs to generate knowledge explaining the mechanism of the effect of self-management on LVAD treatment outcomes.

Telemonitoring and Care Program for Left Ventricular Assist Device Patients During COVID-19 Outbreak: A European Experience

Coronavirus disease 2019 (COVID-19) radically modified the organization of healthcare systems with shutdown of routine activities and outpatient clinics. Herein, we report our institutional experience with a Telemonitoring and Care Program (TC-Program) to monitor and support left ventricular assist device (LVAD) patients during COVID-19 outbreak. This single-arm cohort study analyzed 156 patients who entered the TC-Program at our institution between April and August 2020. The TC-Program was based on routine phone calls to patients and a 24/7 emergency line. In November 2020, patients were asked for feedback on the TC-Program and checked for survival, transplant, or explant. The primary endpoint was the rate of TC-Program-driven interventions. Patients (males: 82.8%) were 61 years old (interquartile range [IQR]: 53.0-67.5) and on LVAD support for 1,266 days (IQR: 475-2,211). Patients were included in the TC-Program for a median time of 99 days (min:15, max:120) and received a median number of six phone calls (min:1, max:14). Twenty-three patients (14.7%) were referred for clinical evaluation after phone contact. Two patients (1.27%) were diagnosed with COVID-19: one of them died after intensive care, and one remained paucisymptomatic and recovered. Three patients asked to exit the program considering it not useful while the others gave high rates in terms of usefulness (median: 9, IQR: 8-10), information (median: 9, IQR: 8-10), good medical care (median: 9, IQR: 8-10), and psychologic support (median: 8, IQR: 7-10). A TC-Program based on the four ICSA principles (Inform, Care, Support, and Adapt) is feasible in LVAD patients and can be rapidly implemented during the COVID-19 pandemic.

Patient-Reported Issues Following Left Ventricular Assist Device Implantation Hospitalization

The purpose of this study was to explore the information reported by patients via a smartphone application (VAD Care App) used for left ventricular assist device (LVAD) self-care monitoring and reporting post hospital discharge. Specific aims were to examine the type and frequency of issues reported by patients through the app during months 1, 3, and 6 postdischarge. An exploratory-descriptive research design was used with 17 patients (12 males and 5 females) with durable LVADs, mean age of 48.6 ± 16 years. Data generated by the patients' daily smartphone app usage more than 6 months were extracted from the server. Data were coded and clustered according to issues reported by patients via the app and analyzed with descriptive statistics. Three clusters of issues were found: physiologic, behavioral (self-care), and signs and symptoms. LVAD flows and pulsatility indices, hypertension, driveline care, and heart failure symptoms were worse at month 1, and then appeared to improve at months 3-6. However, abnormal levels of the international normalization ratio were common at all assessment points. Further research is needed to understand the mechanism of the reported issues on treatment outcomes, then develop and test interventions to inform evidence-based practice and clinical guidelines for smartphone apps used in LVAD self-care monitoring.

The left ventricular assist device as a patient monitoring system

Technological progress of left ventricular assist devices (LVADs) towards rotary blood pumps and the optimization of medical management contributed to the significant improvements in patient survival as well as LVAD support duration. Even though LVAD therapy is now well-established for end-stage heart failure patients, the long-term occurrence of adverse events (AE) such as bleeding, infection or stroke, still represent a relevant burden. An early detection of AE, before onset of major symptoms, can lead to further optimization of patient treatment and thus mitigate the burden of AE. Continuous patient monitoring facilitates identification of pathophysiological states and allows anticipation of AE to improve patient management. In this paper, methods, algorithms and possibilities for continuous patient monitoring based on LVAD data are reviewed. While experience with continuous LVAD monitoring is currently limited to a few centers worldwide, the pace of developments in this field is fast and we expect these technologies to have a global impact on the well-being of LVAD patients.

Surgery and the Smartphone: Can Technology Improve Equitable Access to Surgical Care?

Unfortunately, many patients in the United States experience disparities in access to surgical care, including geographic constraints, limited transportation and time, and financial hardships. Living in a "surgical care desert" results in a delay in care, driving up health care costs and reducing quality of care. In the age of COVID-19, patient access to health care has been further diminished by physical distancing guidelines, naturally increasing the need for innovative telehealth solutions. In this review, we focus on using smartphones for mobile health technology (mHealth) in the delivery of surgical care. This study is aimed at a general surgical audience that may be interested in exploring how mHealth can improve both access and health care quality for surgical patients and their families. We review the current uses of mHealth by surgeons for surgical site infection, new models of the perioperative surgical home, acute care surgical triage, remote patient monitoring devices, and evaluation and management of surgical consultations in the patient's home. We also review institutional and governmental barriers to the adoption of mHealth and offer some preliminary solutions that may aid the surgeon who wishes to implement this technology in their day-to-day practice.

Electromagnetic interference between implantable cardiac devices and continuous-flow left ventricular assist devices: a review

Many patients with continuous-flow left ventricular assist devices (CF-LVAD) have other, co-existing implantable cardiac devices. While such devices often function appropriately, there is potential for electromagnetic interference (EMI). A literature review was performed to identify cases of EMI between CF-LVAD and other implanted cardiac devices to better understand their etiology, outcomes, and the strategies used to overcome such interference. The cases identified included interference between CF-LVAD and pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy. The EMI reported in the current literature can be broken down into two general categories: interference leading to difficulty establishing telemetry and interference leading to impaired electrical signal sensing. Such interference led to inappropriate shock delivery in some cases. The type of interference, and thus treatments, differed and were device dependent. The strategies employed to reduce interference included metal shielding, physical manipulation to increase the distance between devices, and even exchange of the implanted device with another brand of the same class. To avoid such EMI in the future, physicians must be aware of the reported interference between certain devices, and manufacturers must work more closely to increase the compatibility of implanted cardiac devices.

Mobile Health Monitoring of Cardiac Status

Cardiovascular diseases (CVDs) are responsible for more deaths than any other cause, with coronary heart disease and stroke accounting for two-thirds of those deaths. Morbidity and mortality due to CVD are largely preventable, through either primary prevention of disease or secondary prevention of cardiac events. Monitoring cardiac status in healthy and diseased cardiovascular systems has the potential to dramatically reduce cardiac illness and injury. Smart technology in concert with mobile health platforms is creating an environment where timely prevention of and response to cardiac events are becoming a reality.

Out of hospital management of LVAD patients during COVID-19 outbreak

Coronavirus disease 2019 (COVID‐19) is a pandemic touching thousands of people all around the world. Patients supported with left ventricular assist devices (LVADs) are affected by long‐standing cardiovascular diseases and subjected to variations of the normal cardiovascular physiology, thus requiring an even closer monitoring during the COVID‐19 outbreak. Nevertheless, the COVID‐19 pandemic led to a drastic reduction in routine clinical activities and a consequent risk of looser connections between LVAD patients and their referring center. Potential deleterious effects of such a situation can be a delayed recognition of LVAD‐related complications, misdiagnosis of COVID‐19, and impaired social and psychological well‐being for patients and families. As one of the largest LVAD programs worldwide, we designed a sustainable and enforceable telemonitoring algorithm which can be easily adapted to every LVAD center so as to maintain optimal quality of care for LVAD patients during the COVID‐19 pandemic.

Telemonitoring in Heart Failure Management

Telemonitoring (TM) aims to predict and prevent worsening heart failure (HF) episodes and improve self-care, patient education, treatment adherence and survival. There is a growing number of TM options for patients with HF, but there are numerous challenges in reaching positive outcomes. Conflicting evidence from clinical trials may be the result of the enormous heterogeneity of TM devices tested, differences in selected patient populations and variabilities between healthcare systems. This article covers some basic concepts of TM, looking at the recent advances in the most frequently used types of TM and the evidence to support its use in the care of people with HF.

Continuous LVAD monitoring reveals high suction rates in clinically stable outpatients

Suction of the left ventricle can lead to potentially life‐threatening events in left ventricular assist device (LVAD) patients. With the resolution of currently available clinical LVAD monitoring healthcare professionals are unable to evaluate patients’ suction occurrences in detail. This study investigates occurrences and durations of suction events and their associations with tachycardia in stable outpatients. Continuous high‐resolution LVAD data from HVAD patients were analyzed in the early outpatient period for 15 days. A validated suction detection from LVAD signals was used. Suction events were evaluated as suction rates, bursts of consecutive suction beats, and clusters of suction beats. The occurrence of tachycardia was analyzed before, during, and after suction clusters. Furthermore, blood work, implant strategy, LVAD speed setting, inflow cannula position, left ventricular diameters, and adverse events were evaluated in these patients. LVAD data of 10 patients was analyzed starting at 78 ± 22 postoperative days. Individuals’ highest suction rates per hour resulted in a median of 11% (range 3%‐61%). Bursts categorized as consecutive suction beats with n = 2, n = 3‐5, n = 6‐15, and n > 15 beats were homogenously distributed with 10.3 ± 0.8% among all suction beats. Larger suction bursts were followed by shorter suction‐free periods. Tachycardia during suction occurred in 12% of all suction clusters. Significant differences in clinical parameters between individuals with high and low suction rates were only observed in left ventricular end‐diastolic and end‐systolic diameters (P < .02). Continuous high‐resolution LVAD monitoring sheds light on outpatient suction occurrences. Interindividual and intraindividual characteristics of longitudinal suction rates were observed. Longer suction clusters have higher probabilities of tachycardia within the cluster and more severe types of suction waveforms. This work shows the necessity of improved LVAD monitoring and the implementation of an LVAD speed control to reduce suction rates and their concomitant burden on the cardiovascular system.

Remote monitoring for better management of LVAD patients: the potential benefits of CardioMEMS

Left ventricular assist devices (LVAD) are frequently used in the treatment of end-stage heart failure (HF), and due to the shortage of heart donors and destination programs, it is likely to keep on growing. Still, LVAD therapy is not without complications and morbidity and rehospitalization rates are high. New ways to improve LVAD care both from the side of the patient and the physician are warranted. Remote monitoring could be a tool to tailor treatment in these patients, as no feedback exists at all about patient functioning on top of the static pump parameters. We aim to provide an overview and evaluation of the novel remote monitoring strategies to optimize LVAD management and elaborate on the opportunities of remote hemodynamic monitoring with CardioMEMS, at home in these patients as the next step to improve care.