The IMPULSE Study: Pilot

Study Summary

Continuous-flow (CF) left ventricular assist devices (LVADs) are an important tool in the treatment of end-stage heart failure, affording patients significantly improved quantity and quality of life. In recent years, tens of thousands of LVADs have been implanted worldwide, with nearly 1,000 at the Texas Heart Institute (THI). Despite the benefits from LVAD therapy, one major weakness is the high frequency of late strokes, reported up to 19%. CF LVADs minimize or remove the pulsatility within the blood system, introducing a new and incompletely understood physiology. Increased sympathetic ("fight or flight" nervous system) tone secondary to lack of pulse in the blood system can cause high blood pressure, with subsequent hemorrhaging strokes (bleeding into the brain) are one possible explanation for this high adverse event rate in CF LVAD patients. A simple intervention to decrease the increased sympathetic tone is called "ischemic conditioning"; a sphygmomanometer (blood pressure cuff) is placed on the patient's arm to compress a major artery (ischemia) with subsequent release of the cuff (reperfusion) for set periods of time. This has been shown to reduce blood pressure and major adverse cardiovascular events in other patient populations. We plan to conduct a trial to evaluate this intervention, ischemic conditioning, in patients with CF LVADs. We hypothesize that IC will cause a reduction in blood pressure and strokes in this patient population.

Primary Outcome

Patients will follow a standard, validated protocol for this non-invasive technique for 6 weeks, followed by 6 weeks in the control phase (or vice versa based on randomization of order). Each week, they will have Doppler blood pressure measurements and blood samples drawn for analysis.

Interventions

• OTHER Remote Ischemic Conditioning (using Sphygmomanometer)