Implantable Telehealth
MEDICAL DEVICES
Implantable Telehealth
Cardiovascular Telemonitoring
Overview
One of the largest financial burdens of healthcare is readmission following hospital discharge. Patients with complicated problems are often discharged when barely stabilized, to environments that are less easily controlled than hospital settings, often on new and multiple medications. For relatively common and serious illnesses like congestive heart failure (CHF)(1), with it’s thin margin for optimized control, this is a recipe for frequent relapses and hospital returns or increased mortality. Telehealth can address these concerns by maintaining contact with patients, measuring daily metrics, and making appropriate decisions to improve the patient’s condition before requiring a hospital visit.
In a meta-analysis of 25 studies, the use of non-invasive telemonitoring (blood pressure, pulse, weight, ECG analysis) was associated with a 21% relative risk reduction in CHF readmission and 34% for all cause mortality (p<0.01 for both).(2)
However, subsequent randomized prospective trials of non-invasive monitoring versus standard care showed no benefit to non-invasive monitoring of CHF (3,4). One drawback of non-invasive monitoring is that it depends on “patient-activation” and both of these studies showed progressively decreased adherence to monitoring and phone calls among participants (down to about 50% by the end of the studies).
So herein lies the major advantage of smart implantable devices, which can perform very frequent if not continuous assessment, store the information for future transmission and study, or optimally provide “closed-loop” rapid analysis and treatment, without any human intervention.
Devices
Implantable defibrillators and pacemakers: These are perfect examples of classic closed-loop systems, necessary in this case because there is no time for human intervention. Detected arrhythmias like asystole and ventricular fibrillation are fatal in minutes so the devices need to reliably detect and deliver appropriate therapy. These devices can also store important non-fatal information that can be wirelessly transmitted at prescribed intervals, with analysis leading to indicated medication and device changes. ICDs have been proven beyond doubt to save lives from arrhythmia, but beyond delivering prompt electrical therapy, they can also pass along important telemonitoring information. Identifying non-fatal rhythm changes that can predict worsening heart failure, readmissions and death were significantly reduced in the IN-TIME trial (5).
CardioMEMS HF System: This is a novel pressure sensor that can be implanted inside a pulmonary artery branch during a relatively simple and low risk outpatient percutaneous procedure. The device can wirelessly transmit pressure data which is uploaded to servers that physicians and staff can access and make adjustments prior to the patient developing overt heart failure. In patients with moderate to severe CHF, the single-blinded prospective randomized CHAMPION trial (6) demonstrated a 37% decrease in CHF readmissions.
Benefits
-More passive data acquisition (less patient participation) than non-invasive monitoring and in the case of closed-loop systems, self-contained to deliver immediate therapies which have been shown to be life-saving in selected patients).
-Reduction in CHF readmissions from use of tele-monitoring functions
Disadvantages
-Cost (although there is some evidence that this technology may be actually cost-saving overall due to the decreased morbidity, the strength of evidence is weak.)
-Risks associated with the invasive procedure, implanting and maintaining a foreign material (somewhat accounted for in the study results)
-Many health systems are not technically capable of properly integrating or administering such a program; employing additional personnel and purchasing additional equipment, licenses, etc.
-Reimbursement remains an issue, and selection of which patients are best served by invasive monitoring has not yet been optimized
-Mixed data on telehealth in general, and it isn’t clear where invasive monitoring fits on this rapidly growing sector.
Future Directions
-Reproducing results and refining patient selection and intervention algorithms
-Refining cost/benefit analyses
-Patients are their own worst enemies. There will be a continued effort toward removing active patient participation from diagnostic and treatment algorithms. Ultimately, the role of medical staff providing synchronous or nearly synchronous care will be reduced as much as possible (for example, adding a diuretic delivery to the pulmonary artery sensor system much like an insulin pump responds real time to measured blood glucose.)
1 - Fraiche A.M., Eapen Z.J., McClellan M.B. (2017) Moving Beyond the Walls of the Clinic. JACC: Heart Failure 5(4):297-304.
2 - Inglis S.C., Clark R.A., McAlister F.A., et al. (2010) Structured telephone support or telemonitoring programmes for patients with chronic heart failure. Cochrane Database Syst Rev (8):CD007228.
3 - Chaudhry S.I., Mattera J.A., Curtis J.P., et al. (2010) Telemonitoring in patients with heart failure. N Engl J Med 363:2301–2309.
4 - Ong M.K., Romano P.S., Edgington S., Aronow H.U. (2016) Effectiveness of remote patient monitoring of hospitalized patients with heart failure: the Better Effectiveness After Transition-Heart Failure (BEAT-HF) randomized clinical trial. JAMA Intern Med 176:310–318.
5 - Hindricks G., Taborsky M., Glikson M., et al. (2014) Implant-based multiparameter telemonitoring of patients with heart failure (IN-TIME): a randomised controlled trial. Lancet 384:583–590.
6 - Abraham W.T., Adamson P.B., Bourge R.C., et al. (2011) Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: a randomised controlled trial. Lancet 377:658–666.
Submitted by Dave Boston
