RESUMEN
Spinal cord stimulation (SCS) is a well-established treatment for chronic neuropathic pain. However, over- or underdelivery of the SCS may occur because the spacing between the stimulating electrodes and the spinal cord is not fixed; spacing changes with motion and postural shifts may result in variable delivery of the SCS dose and, in turn, a suboptimal therapy experience for the patient. The evoked compound action potential (ECAP)-a measure of neural activation-may be used as a control signal to adapt SCS parameters in real time to compensate for this variability. In this prospective, multicenter, randomized, single-blind, crossover trial, reduction in overstimulation intensity was used as a perceptual measure to evaluate a novel ECAP-controlled, closed-loop (CL) SCS algorithm relative to traditional open-loop (OL) SCS. The primary outcome used a Likert scale to assess sensation during activities of daily living with CL versus OL SCS. Of the 42 subjects in the intent-to-treat analysis set, 97.6% had a reduction in sensation with CL versus OL SCS. The primary objective was met as the lower confidence limit (87.4%) exceeded the performance goal of 50% (P < .001). A total of 88.1% (37/42) of subjects preferred CL and 11.9% (5/42) preferred OL SCS. SCS dose consistency during CL SCS was demonstrated by the reduced variability in ECAP amplitude with CL SCS (standard deviation: 8.72 µV) relative to OL SCS (standard deviation: 19.95 µV). Together, these results demonstrate that the ECAP-controlled, CL algorithm reduces or eliminates unwanted sensation, and thereby provides a more preferred and consistent SCS experience. PERSPECTIVE: Patients with chronic pain need durable and dependable options for pain relief. SCS is an important therapy option, and new technology advancements could improve long-term therapy use. CL SCS offers a preferred and more consistent therapy experience for patients that could lead to increased therapy utilization and reliable therapy outcomes.
RESUMEN
BACKGROUND: Heart failure disproportionately affects Black patients. Whether differences among race influence outcomes in advanced heart failure with use of a fully magnetically levitated continuous-flow left ventricular assist device remains uncertain. METHODS: We included 515 IDE (Investigational Device Exemption) clinical trial patients and 500 Continued Access Protocol patients implanted with the HeartMate 3 left ventricular assist device in the MOMENTUM 3 study (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3). Outcomes were compared between Black and White left ventricular assist device recipients for the primary end point of survival free of disabling stroke or reoperation to replace or remove a malfunctioning device at 2 years, overall survival, adverse events, 6-minute walk distance, and quality of life scores. RESULTS: Of 1015 HeartMate 3 patients, 675 were self-identified as White and 285 as Black individuals. The Black patient cohort was younger, more obese and with a history of hypertension, and more nonischemic cause of heart failure, relative to the White patient group. Black and White patients did not experience a difference in the primary end point (81.1% versus 77.9%; hazard ratio, 1.08 [95% CI, 0.76-1.54], P=0.6568). Black patients were at higher risk of adverse events (calculated as events per 100 patient-years), including bleeding (75.4 versus 63.5; P<0.0001), stroke (9.5 versus 7.2; P=0.0183), and hypertension (10.1 versus 3.2; P<0.0001). The 6-minute walk distance was not different at baseline and 6 months between the groups, however, the absolute change from baseline was greater for White patients (median: +183.0 [interquartile range, 42.0-335.3] versus +163.8 [interquartile range, 42.3-315.0] meters, P=0.01). The absolute quality of life measurement (EuroQoL group, 5-dimension, 5-level instrument visual analog scale) at baseline and 6 months was better in the Black patient group, but relative improvement from baseline to 6 months was greater in White patients (median: +20.0 [interquartile range, 5.0-40.0] versus +25.0 [interquartile range, 10.0-45.0]; P=0.0298). CONCLUSIONS: Although the survival free of disabling stroke or reoperation to replace/remove a malfunctioning device at 2 years with the HM 3 left ventricular assist device did not differ by race, Black HeartMate 3 patients experienced a higher morbidity burden and smaller gains in functional capacity and quality of life when compared with White patients. These findings require efforts designed to better understand and overcome these gaps through systematic identification and tackling of putative factors. Registration: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02224755 and NCT02892955.