The Duke Primary Care Tailored to You (TTY) Blood Pressure Control Pilot Study
Phase: NA
Conditions: Hypertension
Sponsor: Duke University

The Duke Primary Care Tailored to You (TTY) Blood Pressure Control Pilot 
Study
Document Date: 06/14/2022
NCT05141175

The Duke Primary Care Tailored to You (TTY) Blood 
Pressure Control Pilot Study 
Research Summary 
Research Abstract 
Suboptimal blood pressure (BP) lowering therapy is a key reason for failing to reach hypertension 
control targets. Both clinical inertia and patient adherence contribute to suboptimal BP-lowering 
therapy. Impedance cardiography (ICG) is a simple, noninvasive method to assess a person’s 
hemodynamic state and the pathophysiology contributing to high BP. Armed with such an 
understanding, a clinician can tailor medication selection to the individual patient. In this pilot study, we 
will test a protocol and procedures designed to investigate the clinical utility and feasibility of ICG-based 
hypertension therapy in the primary care setting. Twenty patients with uncontrolled hypertension 
(office BP≥140/90 mm Hg) who are taking at least one BP-lowering medication will be enrolled in this 
study and followed for four-months. Participants will undergo ICG in the office setting during their clinic 
visit, and ICG assessment will be used to guide medication selection. Follow-ups with repeat BP 
measurement and ICG-guided medication titration will occur monthly until BP is controlled or four-
months have passed. Outcomes (at four months) will be percent of patients who attain controlled BP 
and mean BP achieved as well as feasibility outcomes (enrollment and completion rates). This study is 
low-risk, carrying the same risks as standard care for patients with hypertension. Participants' BP will 
continue to be monitored in the standard manner in addition to ICG assessment. 
Primary study objectives: To test procedures and gather preliminary data on the potential efficacy of 
incorporating impedance cardiography (ICG) into the assessment of patients with hypertension in the 
primary care setting to provide the clinician guidance on individualizing therapy to improve blood 
pressure (BP) control. Potential efficacy will be assessed as percentage of participants in whom BP 
control is attained. 
Secondary study objectives: Collect preliminary data for informing a larger study. 
Objectives & hypotheses to be tested 
To assess feasibility and potential effectiveness of incorporating impedance cardiography (ICG) 
assessments into the care of patients with uncontrolled hypertension. As a pilot study, we will not be 
testing a hypothesis. 
Background & Significance 
Control of high blood pressure (BP) is one of the most important strategies for prevention of stroke and 
cardiovascular diseases. In addition to the adoption of appropriate lifestyle modifications, from a clinical 
standpoint, achieving BP control requires several steps that culminate in choosing antihypertensive 
medication that is effective for the patient. In practice, BP-lowering medication is chosen empirically or 
based on clinical judgment taking into consideration clinical factors such as age, lifestyle and 
comorbidities. Ideally, however, BP-lowering medication should be matched to the patient’s underlying 

pathophysiology. Our central hypothesis is that hypertension control can be improved by addressing this 
gap. 
In fact, a suboptimal medication regimen is the most common reason for uncontrolled BP. Some 
medications may simply not be effective for certain patients, and some medications can even cause a 
paradoxical BP increase. As opposed to the current strategy of choosing BP-lowering medications largely 
arbitrarily, measurement of hemodynamic parameters using impedance cardiography (ICG) may allow a 
better alignment of medication choice with a patient’s underlying hypertensive pathophysiology. ICG 
provides information on vascular resistance and thoracic fluid status in addition to resting heart rate. A 
systematic review and meta-analysis of five studies suggested that ICG may be valuable as an adjunct to 
therapeutic decision-making in the treatment of hypertension.(Ferrario C, et al. 2010.) The review 
identified two randomized controlled trials (total 268 patients) of ICG-guided treatment with patients 
randomized to ICG-guided therapy about twice as likely to achieve BP control. However, both trials are 
dated, and baseline control rates were low (33% in one trial and 27% in another). Duke Primary Care, 
which uses the attached hypertension medication algorithm, currently has an overall 75.1% BP control 
rate. Our goal is to determine whether a tailored approach using ICG can facilitate an even greater 
proportion of our population attaining control of their BP, thereby reducing their risk for untoward 
cardiovascular events. This pilot study represents a first step in this line of research and quality 
improvement. 
Design & Procedures 
The purpose of this pilot study is to test procedures and gather preliminary data on the potential 
effectiveness of incorporating impedance cardiography (ICG) into the assessment of patients with 
hypertension in the primary care setting to provide the clinician guidance on individualizing therapy to 
improve blood pressure (BP) control. ICG is not an experimental or investigational device; it is a low-
cost, noninvasive technology that easily measures a person’s hemodynamic phenotypic profile. 
This pilot study will take place in the South Durham Duke Primary Care Clinic. The clinic serves 
approximately 15,700 patients, with an estimated hypertension diagnosis prevalence of 28.3%. As a pilot 
study, this will be a non-randomized, single-arm, prospective study. BP and ICG data will be recorded in 
a REDCap database. Data on BP-lowering medications will be collected by abstracting data from the EHR 
and entering it into the REDCap database. 
The ICG system provides a printed report that indicates whether a person's hemodynamic state is 
predominantly one that is vasoconstricted, hyperdynamic, or mixed. The participating clinicians will 
have received teaching on the reports via a presentation delivered by one of the study investigators. 
Participating clinicians can refer to a separate table that provides a list of medication options suited to 
address each of these states based on their mechanism of action. The table was developed by MediSync 
for their MedEngine algorithm that is configured to align medication choices based on the hemodynamic 
findings from the ICG readings.  This decision support tool was created so as to organize these 
medications based on their mechanism of action and is consistent with the evidence-based treatment of 
hypertension. In other words, the table is simply a way to organize BP-lowering medications matched to 
hemodynamic state according to their mechanism of action. The table lists appropriate standard of care 
medication options.  The clinician can use the information to guide selection of the next BP-lowering 
medication. The ultimate decision on therapy rests with the patient's clinician. ICG data will not be put 
into the Duke SOC process. ICG data will not be incorporated in the DPC hypertension algorithm. 

Participating clinicians will use clinical judgment, informed by ICG data and a table of standard of care BP 
medications for different hemodynamic states, to adjust medications.  
For participants whose office BP is controlled prior to the 4-month visit, we will conduct a chart review 
to assess last clinic BP obtained, which will be entered into REDCap. 
We will conduct anonymous surveys with both patients and providers who participated in the study to 
better understand acceptability and feasibility. These will be administered using REDCap and will include 
a short implied consent statement. 
Selection of Subjects 
We will recruit 20 patients (18 years or older) for this pilot feasibility study assessing ICG-guided 
hypertension management as an alternative to standard algorithm-based care (see Hypertension 
Medication Algorithm provided as an attachment) for improving BP control. Patients will be eligible if 
they have a documented diagnosis of hypertension (ICD 401.XX) and their most recent office systolic BP 
average measured using automated office BP (AOBP) is ≥140 mmHg systolic or ≥90 mmHg diastolic and 
they are currently prescribed at least one BP-lowering medication. All patients will already be under the 
care of a primary care clinician. AOBP is already the standard form of BP assessment in Duke Primary 
Care. 
Subject Recruitment and Compensation 
Describe recruitment procedures, including who will introduce the study to potential subjects. Describe 
how you will ensure that subject selection is equitable and all relevant demographic groups have access 
to study participation (per 45 CFR 46.111(a) (3)). Include information about approximately how many 
DUHS subjects will be recruited. If subjects are to be compensated, provide specific prorated amounts to 
be provided for expenses such as travel and/or lost wages, and/or for inducement to participate. 
Study staff will attend clinic days. Eligible patients of participating clinicians will be identified and 
informed about the study by the medical assistant. On study days, eligible patients of participating 
clinicians (who will have been trained on protocol) will be approached consecutively until the end of the 
clinic day or until target enrollment is complete. A study coordinator will work with the scheduled study 
clinician(s) and their medical assistant(s) to identify patients who may be eligible before the start of the 
clinic session.  During the vital signs check-in procedures, the medical assistant will inform potentially 
eligible participants about the study  if their check-in BP is ≥140 mmHg systolic or ≥90 mmHg diastolic. If 
an eligible patient is interested in participating, the medical assistant will introduce the patient to the 
study coordinator who will provide more information and obtain informed consent. Based on the 
number of patients with hypertension, it is estimated this pilot study will reach target enrollment in 5 or 
fewer study enrollment days. There is no compensation provided to participants. The ICG assessment 
will be provided free of charge. 
Study Interventions 
If not already presented in #4 above, describe study-related treatment or use of an investigational drug 
or biologic (with dosages), or device, or use of another form of intervention (i.e., either physical 
procedures or manipulation of the subject or the subject’s environment) for research purposes. 

If a patient approached by the medical assistant is interested in participating, the medical assistant will 
“hand-off” the patient to a study coordinator. The study coordinator will obtain informed consent and 
enter study information into a secure Redcap database. An in-office ICG assessment will then be 
performed by either the study coordinator or a trained clinic nurse. The procedure uses four electrodes 
(2 electrodes on the right ankle and 2 electrodes on the left wrist) and takes approximately 5 minutes to 
perform while the participant lies on an exam table. It is painless and completely noninvasive (does not 
even require chest to be bare). The ICG report will be printed and presented to the participant’s 
clinician, who will then see the patient. The report will contain a recommendation for therapy based on 
the result. Participating clinicians will have all been trained about ICG and how to interpret the report. 
Participating patients will be seen in a hypertension follow-up visit 1-month later and have repeat AOBP 
measured in the office. If BP is <140/90 mmHg, they will continue the current BP-lowering medication 
regimen and follow-up per usual care. If AOBP average is ≥140/90 mmHg, the participating patient will 
have repeat ICG and therapy adjustment as above with another one-month follow-up. The four-month 
visit AOBP average will be used as the endpoint for this pilot study. For participants whose office BP is 
controlled prior to the 4-month visit, we will conduct a chart review to assess last clinic BP obtained, 
which will be entered into REDCap. 
Data Analysis 
As this is a pilot study for feasibility, our main outcomes will be enrollment and completion rates. 
Nonetheless, we will assess improvement in BP control (both percent at goal <140/90 mmHg as well as 
average mmHg reduction in BP) at 4-months. For participants whose office BP is controlled prior to the 
4-month visit, we will conduct a chart review to assess last clinic BP obtained, which will be entered into 
REDCap. Characteristics of participants will be tabulated by simple means and percentages. We will also 
tabulate number and categories of anti-hypertensive medications participants are prescribed.