Early detection of HVAD pump thrombosis based on technical analysis and power consumption measurements.

BACKGROUND: Continuous-flow left ventricular assist devices (LVADs) have been extensively used in a strategy of bridge to orthotopic heart transplant and destination therapy. The usage of LVAD, however, is not free from limitations such as device-related adverse events, including pump thrombosis (PT). We aimed to develop an algorithm of early PT detection based on the maintenance parameters monitored by the implanted device. METHODS: We analyzed log files of 101 patients implanted with HeartWare pump (HVAD) with 18 PT events among them. For signal processing, we used the open-high-low-close format transformation and typical price (TP) technical analysis indicator. Model parameters were tuned with 5-fold cross-validation, and the final performance was measured on a separate group of patients. RESULTS: Our algorithm achieved 100% sensitivity and 100% specificity of indications. In the final evaluation, alarms preceded the clinical acknowledgement of events by 2 days and 20 h on average. In the worst-case scenario, an alarm was raised 1 day and 8 h prior to the event. CONCLUSIONS: The proposed algorithm could be installed to work directly with the device controller and provide clinicians with automatic readings analysis, raising an alarm when there is a high probability of thromboembolism. Early event detection could enable better thrombosis management and improve prognosis in patients implanted with HVAD.

Oxidative Stress Markers and Modified Model for End-Stage Liver Disease Are Associated with Outcomes in Patients with Advanced Heart Failure Receiving Bridged Therapy with Continuous-Flow Left Ventricular Assist Devices.

Left ventricular assist device (LVAD) is well established as an alternative treatment for end-stage heart failure (HF) patients. The aim of the study was to determine the prognostic value of oxidative stress markers and the modified Model for End-Stage Liver Disease (modMELD) in patients receiving bridged therapy with continuous-flow LVAD. We prospectively analyzed 36 end-stage HF patients who received LVAD therapy between 2015 and 2018. The total antioxidant capacity (TAC) and total oxidant status (TOS) were measured by the methods described by Erel. The oxidative stress index (OSI) was defined as the ratio of the TOS to TAC levels. The modMELD scores were calculated based on the serum bilirubin, creatinine, and albumin levels. The patients' median age was 58 (50-63.0) years. During the 1.5-years follow-up, a major adverse cardiac event-MACE (death, stroke, or pump thrombosis) was observed in 17 patients (47.2%). The area under the receiver operating characteristics curves (AUCs) indicated a good prognostic power of TAC (AUC 0.7183 (0.5417-0.8948)), TOS (AUC 0.9149 (0.8205-0.9298)), OSI (AUC 0.9628 (0.9030-0.9821)), and modMELD (AUC 0.87 (0.7494-0.9905)) to predict a MACE. Oxidative stress markers serum concentrations, as well as the modMELD score, allow the identification of patients with a risk of MACE.

Short- and long-term outcomes of continuous-flow left ventricular assist device therapy in 79 patients with end-stage heart failure.

INTRODUCTION: An increasing number of patients with end­stage heart failure, along with a shortage of heart donors, necessitates the use of mechanical circulatory support. OBJECTIVES: This single­center retrospective study evaluated short- and long term outcomes of continuous­flow left ventricular assist device (CF LVAD) therapy in patients with end stage heart failure. PATIENTS AND METHODS: We collected and assessed data of 79 patients (77 men, 2 women; mean age, 50.3 years; mean INTERMACS profile, 3.1) implanted with a CF­LVAD between 2009 and 2017 (HeartMate 3 in 19 patients [24%]; HeartMate 2 in 9 [11.4%]; and HeartWare in 51 [64.6%]). RESULTS: The mean time on CF-LVAD support was 604 days (range, 1­1758 days). There were 2 device exchanges due to pump thrombosis and 1 explantation due to heart regeneration; 9 patients (11.4%) underwent heart transplant. Stroke (nondisabling, 48%) occurred in 27.8% of patients (ischemic in 9 patients; hemorrhagic, in 14; both types, in 1) despite the standardized anticoagulation regimen. Major gastrointestinal bleeding and pump thrombosis were reported in 13 patients (16.5%), while 18 patients (22.8%) developed driveline infections (recurrent in 15 patients [19%]). Hemorrhagic stroke and bacteremia had a negative impact on survival. Hemorrhagic stroke was the main cause of death. Survival probability was 0.9 at 1 month and 0.81, 0.71, 0.61, and 0.53 at 1, 2, 3, and 4 years, respectively. CONCLUSIONS: Although CF­LVAD support is associated with substantial adverse events, they do not significantly affect mortality (except hemorrhagic stroke and bacteremia). Novel devices seem to overcome these limitations, but larger studies are needed to support these findings.

Simplified, less-invasive left ventricular assist device implantation in patients with post-coronary artery bypass grafting.

Less-invasive left ventricular assist device implantation is becoming the technique of choice for implementation of new-generation heart pumps. The less-invasive technique is particularly useful for patients with a history of cardiac surgical procedures, such as coronary artery bypass grafting. Yet, in redo cases, severe pericardial adhesions may force experienced operators to opt for alternative outflow graft placement, such as in the descending aorta. We propose a surgical technique in which the left ventricular device is implanted through a limited thoracic incision, with the outflow graft anastomosed to the ascending aorta, avoiding collision with coronary bypass grafts. The key element of the proposed technique is a tunnel connecting 2 pleural cavities, in which the outflow graft is placed, entirely bypassing the pericardium.

Mechanical circulatory support is effective to treat pulmonary hypertension in heart transplant candidates disqualified due to unacceptable pulmonary vascular resistance.

INTRODUCTION: High pulmonary vascular resistance (PVR) in orthotopic heart transplantation (OHT) candidates is a risk factor of right ventricle failure after the procedure. However, the increase of PVR may be a consequence of the life-threatening deterioration of the left ventricle function. The use of mechanical circulatory support (MCS) seems to be the best solution, but it is reimbursed only in active OHT candidates. AIM: We performed a retrospective analysis of MCS effectiveness in maintaining PVR at values accepted for OHT. MATERIAL AND METHODS: Starting from the year 2008 we identified 6 patients (all males, 42.8 ±17 years old) with dilated (n = 3), ischemic (n = 2), and restrictive cardiomyopathy (n = 1) in whom MCS - pulsatile left ventricle assist device (LVAD, n = 4), continuous flow LVAD (n = 1), and pulsatile biventricular assist device (BIVAD, n = 1) - was used at a time when PVR was unacceptable for OHT, and the reversibility test with nitroprusside was negative. After an average time of support of 261 ±129 days they were all transplanted. RESULTS: Right heart catheterization (RHC) results before MCS implantation were as follows: pulmonary artery systolic, diastolic, and mean pressure (PAPs/d/m) 60 ±20/28 ±7/40 ±11 mm Hg, pulmonary capillary wedge pressure (PCWP) 21 ±7 mm Hg, transpulmonary gradient (TPG) 19 ±7 mm Hg, cardiac output (CO) 3.6 ±0.8 l/min, PVR 5.7 ±2.1 Wood units (WU). Right heart catheterization results during MCS therapy were as follows: PAPs/d/s 27 ±11/12 ±4/17 ±6 mm Hg, PCWP 10 ±4 mm Hg, TPG 7 ±4 mm Hg, CO 5.1 ±0.7 l/min, PVR 1.4 ±0.6 WU. None of the patients experienced right ventricle failure after OHT with only one early loss due to multiorgan failure. CONCLUSIONS: Mechanical circulatory support is an effective method of pulmonary hypertension treatment for patients disqualified for OHT due to high PVR.

Emergency HeartWare Ventricular Assist Device (HVAD) exchange due to pump thrombosis using minimally invasive technique.

Left ventricular assist device (LVAD) thrombosis remains a dreadful complication of mechanical circulatory support, with an incidence of 8-12% depending on the pump type and patient's comorbidities. Fibrinolysis may be considered early in pump thrombosis, but when contraindicated a pump exchange remains the only alternative. This short report documents an emergency LVAD exchange in a 55-year-old man who underwent LVAD (HeartWare Inc) implantation in 2013 as a bridge to transplantation. Four months after the initial surgery, he suffered from a hemorrhagic stroke despite properly managed anticoagulation. On February 17th, 2017 he was re-admitted with LVAD pump thrombosis. As fibrinolysis was contraindicated, an emergency pump exchange was performed via a limited thoracic incision in order to minimize surgical trauma, reduce intraoperative complications and facilitate immediate post-operative recovery. This report documents the very first LVAD pump exchange as well as the first one performed via a minimally invasive approach in Poland.