Heavy Metal Exposure Cardiac Toxicity Index (Lead & Arsenic) Calculator

Heavy Metal Exposure Cardiac Toxicity Index (HM-CTI, Lead & Arsenic): Explanation and Clinical Context The HM-CTI is an evidence-informed, pragmatic index summarizing cardiovascular toxicity risk from two established environmental cardiotoxins: lead and inorganic arsenic. It uses two biomarkers—blood lead level (BLL, µg/dL) and urinary inorganic-related arsenic (iAs+MMA+DMA, µg/L)—to generate a 0–10 score, categorizing risk as Low, Mild, Moderate, or High. Thresholds are derived from epidemiologic data showing cardiovascular harm even at low exposure levels, linked to hypertension, atherosclerosis, ischemic heart disease, stroke, and heart failure.

Rationale for thresholds Lead: Evidence shows adverse effects at BLL <10 and even <5 µg/dL. Cohort data (NHANES) reveal graded increases in cardiovascular mortality across low BLL ranges, supporting targets near background (<2 µg/dL). Arsenic: Urinary inorganic arsenic correlates with heart disease mortality, with risk apparent from low-to-moderate levels.

HM-CTI adopts conservative targets: BLL <2 µg/dL, urinary arsenic <20 µg/L, with escalating points at 2–4.9, 5–9.9, and ≥10 (lead), and 20–49, 50–99, and ≥100 (arsenic). These are literature-guided, not validated thresholds. Interpretation 0–1 (Low): Maintain exposure minimization.

2–3 (Mild): Counsel on exposure sources; repeat biomonitoring in 3–6 months. 4–6 (Moderate): Control exposure source, coordinate assessment, and intensify CV prevention. 7–10 (High): Prioritize urgent mitigation, short-interval follow-up, and possible toxicology referral.

Clinical caveats This is a research prototype, not a validated clinical tool. Prefer arsenic speciation over total arsenic. Account for seafood-derived organic arsenic.

Use consistent laboratory protocols and local thresholds.