Clinical Framework
Perimenopause is the most important cardiovascular prevention window in a woman's life. MERCI is Naviday's clinical framework, currently in development and early testing, designed to detect and track that risk earlier than existing tools allow.
Estrogen is profoundly cardioprotective. It maintains endothelial function, the delicate lining of blood vessels, suppressing inflammatory adhesion molecules and preserving the flexibility that keeps arterial walls healthy. It regulates lipid metabolism, raising HDL cholesterol and lowering LDL. It promotes vasodilation through nitric oxide synthesis, reducing vascular resistance and blood pressure. And it governs calcium handling in vascular smooth muscle, preventing the pathological calcium influx that stiffens arteries and drives calcification.
As perimenopause begins, typically in a woman's 40s, estrogen fluctuates wildly, then falls. These protective effects unravel in sequence. Calcium dysregulation in vascular smooth muscle cells increases vasoconstriction. Vascular calcification risk rises. LDL climbs. HDL falls. Blood pressure elevates. Inflammatory markers spike. Atherosclerosis accelerates along a timeline that mirrors the hormonal transition itself.
This is not a passive consequence of aging. It is an estrogen-driven cardiovascular event unfolding in real time, over years, in women who are still largely asymptomatic by conventional cardiac standards, and largely undetected by conventional cardiac risk tools.
The ASCVD Pooled Cohort Equations, the gold standard for 10-year cardiovascular risk estimation, were built on population data that skews older and predominantly male. They calculate risk from static inputs: age, total cholesterol, HDL, systolic blood pressure, smoking status, diabetes. They do not account for hormonal stage. They do not know where a woman sits in her menopause transition. They cannot see the vasomotor symptoms she experienced last Tuesday, or the HRV decline her wearable captured over the past three months.
MERCI is a clinical framework Naviday has designed and is actively developing within the LUCI platform, currently in clinical review and early testing. It enhances and modernizes the intent of ASCVD risk assessment for the perimenopausal population, applying the same preventive logic to an earlier window, using the real-world data that women are already generating every day. Wearable signals. Logged symptoms. Validated assessment scores. Continuous monitoring between the moments that standard risk tools capture.
The result is earlier signal. A clinician using MERCI is not replacing ASCVD, they are receiving an upstream warning before the ASCVD score has had time to move. That is where prevention lives. That is what MERCI was built for.
“ASCVD tells you the risk. MERCI tells you it's coming, while there is still time to change the trajectory.”
Three interlocking biological mechanisms explain how perimenopause reshapes cardiovascular risk, and why they must be tracked together.
Estrogen stimulates endothelial nitric oxide synthase, keeping arterial walls flexible and resistant to atherosclerotic plaque formation. As estrogen levels fall, nitric oxide availability decreases. Endothelial dysfunction begins , measurable by carotid intima-media thickness and flow-mediated dilation, years before any clinical cardiovascular event manifests. This is the first domino in the vascular cascade.
Estrogen regulates L-type calcium channels in vascular smooth muscle cells. As estrogen declines, calcium influx into arterial walls increases, raising blood pressure, promoting arterial stiffness, and accelerating vascular calcification. Simultaneously, bone calcium that was held in the skeleton by estrogen-driven osteoblast activity begins mobilising into circulation, compounding the vascular calcium load. The result is a form of arterial aging that is hormonally driven, not chronological.
Perimenopause triggers a rapid and clinically significant worsening of lipid profiles. LDL cholesterol rises. HDL falls. Triglycerides increase. The Study of Women's Health Across the Nation (SWAN) documented these changes beginning in the late reproductive stage, years before the final menstrual period, tracking them as a function of hormonal transition rather than age. Standard lipid panels taken during routine primary care miss the rate of change that is the true risk signal.
Research from the SWAN study and the Nurses' Health Study converges on a striking finding: cardiovascular risk doubles within 10 years of menopause. Women who enter menopause early, before age 45, face a 50% higher lifetime CVD risk than those who transition later. The hormonal event is the risk event.
Vasomotor symptoms, hot flashes and night sweats, are not merely discomforts. They are independently associated with subclinical atherosclerosis and greater carotid intima-media thickness, even after controlling for traditional cardiovascular risk factors. A woman reporting frequent vasomotor symptoms at 47 is signalling vascular risk. Current clinical infrastructure has no systematic way to capture and act on that signal.
The window between perimenopause onset and 10 years post-menopause is when lifestyle intervention, clinical monitoring, and, where appropriate, therapeutic decisions change outcomes. After that window, the vascular damage becomes structural. Calcification is irreversible. Atherosclerotic plaques become established. The opportunity to intervene upstream closes.
“Perimenopause is a cardiovascular event as much as it is a reproductive one. We treat it that way.”
Among the data points MERCI draws from are continuous signals that standard point-in-time assessments are not designed to capture. These include, but are not limited to:
01
Frequency and severity of hot flashes and night sweats, logged continuously through LUCI. Vasomotor symptoms are independently predictive of cardiovascular risk, MERCI treats them as a clinical signal, not a nuisance.
02
HRV data pulled from connected wearables and trended over time. Declining HRV is an established early marker of autonomic dysfunction and cardiovascular risk, particularly meaningful when tracked against hormonal staging.
03
Passive and active monitoring of blood pressure trends, capturing the gradual elevation that accompanies estrogen-driven loss of vascular tone, the kind of creeping change that single in-office readings miss entirely.
04
Sleep quality and fragmentation patterns from wearable data. Chronic sleep disruption drives systemic inflammation, dysregulates cortisol, and accelerates cardiovascular risk, a mechanism compounded by night sweats during perimenopause.
05
Establishing where in the menopause transition the patient sits using the Stages of Reproductive Aging Workshop criteria. The clinical meaning of every other data point changes depending on hormonal stage, MERCI accounts for this.
06
The validated Menopause Rating Scale captures somatic, psychological, and urogenital symptom burden. High MRS scores correlate with greater cardiovascular risk trajectory, MERCI integrates this as a composite quality-of-life signal.
MERCI is not a standalone score. It is being developed as an integrated capability within LUCI, designed to be continuously computed, trended, and surfaced to the clinical team before every visit.
LUCI continuously collects data from connected wearables, Apple Health, patient-reported symptoms, and validated clinical assessments. The patient does not have to do anything differently, the signal accumulates passively as she lives her life.
Every data point feeds the MERCI algorithm. The score is recalculated as new data arrives. Trends are plotted longitudinally, so the clinician sees not just where the score is today, but where it has been, and in which direction it is moving, across the full arc of the hormonal transition.
When the MERCI score changes materially, a meaningful shift in risk trajectory, the platform flags it. Not after the appointment. Before it.
Pre-Visit Summary
Before the patient walks in, the practitioner receives the MERCI score, trend, and flagged changes as part of a structured pre-visit summary. No hunting through charts. No incomplete picture.
Score Alerts
If MERCI changes above a clinically meaningful threshold between visits, the system generates an alert. The clinician can decide whether to schedule a proactive check-in or adjust the care plan.
Full Context at a Glance
The practitioner sees the complete picture: vasomotor burden, HRV trend, sleep quality, blood pressure trajectory, hormonal stage, and MRS score, synthesised into a single index with full drill-down available.
MERCI is in active development within the LUCI platform and currently in early clinical review. If you are interested in being part of how this framework evolves, we would like to hear from you.
Talk to Our Clinical Team