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.
Pump thrombosis (PT) is a serious adverse event in patients receiving left ventricular assist devices (LVAD). The study aims to determine whether pump parameters and clinical data may enable early detection of PT. This retrospective study included 88 patients who received an LVAD between 2012 and 2015 among which those with intra-PT were identified. In a propensity score–matched control group observation, time periods were matched with time before thrombosis. International normalized ratio (INR) time in therapeutic range (TTR) and lactate dehydrogenase (LDH) were analyzed for 60 days preceding PT. Furthermore, pump data (power, flow, and speed) in HeartWare ventricular assist devices (HVAD) patients were analyzed 7 days before PT using a mixed-design analysis of variance to investigate temporal changes in pump data. Pump thrombosis occurred in 15 patients (13 males, age 58 ± 10 years, 7 HeartMate II and 8 HVAD). International normalized ratio therapeutic range (2.0–3.0) and acetylsalicylic acid daily doses (100–200 mg) were similar for both groups, but patients with PT had lower TTR (36% vs. 65%; p = 0.025). No significant difference in LVAD power between groups was seen at baseline (p = 0.31), and power did not change in the control group over time (p > 0.99). Lactate dehydrogenase increased already 1 week prior PT and power from 4.4 ± 0.8 W at baseline to 4.9 ± 0.8 W (p = 0.007) 2 days before readmission and to 6.5 ± 1.8 W (p = 0.015) at readmission. Pump thrombosis is associated with a lower percentage of INR TTR and elevated LDH before the event. A better monitoring of pump parameters would enable PT detection already up to 2 days in advance.
Anticoagulation therapy in patients using left ventricular assist device (LVAD) is essential to reduce hemocompatibility related adverse events (HRAEs). Vitamin K-antagonist dosage must be adapted and monitored by INR point-of-care testing (POCT) in outpatients. The study aims to determine if the frequency of INR POCT in LVAD outpatients has an influence on the quality of anticoagulation therapy (ACQ), HRAEs, and outcomes. This retrospective study included n = 48 patients who received LVAD implantation (HMII, HM3, and HVAD) between 2013 and 2017. ACQ (% of INR tests in range, PTR), outcomes and HRAEs using Kaplan–Meier curves were compared in a daily (n = 36) and 3×/week (n = 12) INR POCT group. Further, based on the achieved PTR ranging from 0–60% (poor), 61–70% (acceptable), and 71–100% (well controlled), HRAEs and outcomes were compared. Daily and 3×/week groups were similar in perioperative risk factors and INR target (p = 0.28). Freedom from any HRAE (38.9% vs. 25.0%, p = 0.44), any readmission (72.2% vs. 75.0%, p = 0.97), and 1 year survival (91.7% vs. 91.7%, p = 0.98) were comparable in both groups. The PTR was significantly higher with the daily self-assessments (73.5% vs. 68.4%, p = 0.006). Well vs. poorly controlled INR POCT patients more often had (p = 0.01) a daily POCT frequency (92%) vs. poorly controlled (54%) and significantly higher freedom from neurologic events (96.0 vs. 69.2%, p = 0.024) as well as hemorrhagic strokes (100% vs. 76.9%, p = 0.011). Well-controlled anticoagulation of LVAD outpatients is associated with less neurologic events. The frequency of INR POCT could be one of the key factors in the reduction of HRAEs, so future prospective, large-scale studies should help to clarify the effects.
Ventricular assist devices (VADs) are an established therapeutic option for patients with chronic heart failure. Continuous monitoring of VAD parameters and their adherence to guidelines are crucial to detect problems in an early stage to optimize outcomes. A telephone intervention algorithm for VAD outpatients was developed, clinically implemented and evaluated. During the phone calls, a structured inquiry of pump parameters, alarms, blood pressure, INR, body weight and temperature, exit‐site status and heart failure symptoms was performed and electronically categorized by an algorithm into 5 levels of severity. VAD outpatient outcomes without (n = 71) and with bi‐weekly telephone interviews in their usual care (n = 25) were conducted using proportional hazard Cox regression, with risk adjustment based on a propensity score model computed from demographics and risk factors. From February 2015 through October 2017, 25 patients (n = 3 HeartMate II, n = 4 HeartMate 3 and n = 18 HeartWare HVAD) underwent 637 telephone interventions. In 57.5% of the calls no problems were identified, 3.9% were recalled on the next day because of alarms. In 26.5% (n = 169), the VAD Coordinator had to refer to the physician due to elevated blood pressure (n = 125, >85 mm Hg), INR < 2.0 or > 4.0 (n = 24) or edema (n = 10), 11.9% of the calls led to a follow‐up because of equipment or exit‐site problems. Propensity‐adjusted 2‐year survival (89% vs. 57%, P = 0.027) was significantly higher for the telephone intervention group. Continuous, standardized communication with VAD outpatients is important for early detection of upcoming problems and leads to significantly improved survival.
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