1,329 calculators and references across 60 specialties, with formula confidence shown up front.
6MWD Risk Stratification in Pulmonary Hypertension: Explanation and Clinical Context The 6-minute walk distance (6MWD) is a simple, non-invasive functional test widely used in the assessment of patients with pulmonary arterial hypertension (PAH). It reflects exercise capacity, correlates with hemodynamic severity, and predicts prognosis. Low risk is defined as >440 meters, indicating preserved functional capacity and
Explanation and Clinical Context This calculator helps determine the optimal revascularization approach in acute coronary syndrome based on clinical urgency hemodynamic status ischemic burden and risk features recommended in the 2025 American Heart Association guideline. Revascularization strategies include Immediate reperfusion for ST elevation myocardial infarction or unstable electrical and hemodynamic profiles Ea
ACUITY HORIZONS Score Explanation and Clinical Context The ACUITY HORIZONS risk score is a validated clinical tool that helps estimate the risk of major adverse cardiovascular events in patients presenting with acute coronary syndromes who undergo an early invasive strategy. This score incorporates age, renal function expressed through serum creatinine, hemodynamic status reflected by systolic blood pressure, and the
Aldrete Score Recovery Assessment Explanation and Clinical Context The Aldrete score is a structured bedside tool used to evaluate physiologic recovery after anesthesia or procedural sedation. It grades five domains that reflect the return of baseline neuromuscular function, respiratory stability, hemodynamic stability, level of consciousness and adequate oxygenation. Each domain receives a value from zero to two and
Balloon Pulmonary Angioplasty (BPA) Success Score: Explanation and Clinical Context Balloon Pulmonary Angioplasty (BPA) is an interventional therapy for patients with inoperable or residual chronic thromboembolic pulmonary hypertension (CTEPH). The BPA Success Score estimates the likelihood of achieving hemodynamic normalization (mean pulmonary artery pressure < 25 mmHg) following a series of BPA sessions. The score
: Explanation and Clinical Context Body surface area represents the external surface area of the human body and is widely used in clinical medicine because it correlates more closely with physiological parameters compared to actual body weight. BSA is routinely applied in cardiovascular care, nephrology, oncology, and critical care medicine. In hemodynamics, BSA is essential for calculating cardiac index, which is th
Bova Score: Explanation and Clinical Context Bova Score is a validated clinical tool to stratify early risk in patients with acute pulmonary embolism (PE) and identify those at higher risk of adverse outcomes, including hemodynamic decompensation. The score uses four variables: heart rate >110 bpm (1 point), systolic blood pressure 90–100 mmHg (1 point), elevated cardiac troponin (1 point), and right ventricular dysf
Cardiac Power Output (CPO): Comprehensive Explanation and Clinical Context Cardiac Power Output is a hemodynamic parameter that quantifies the overall pumping capability of the heart by integrating both cardiac output and mean arterial pressure into a single measure. It reflects the amount of hydraulic energy delivered by the heart to circulate blood throughout the body, and it is expressed in Watts. Unlike isolated
Cardiac Power Output Index (CPO Index) Explanation and Clinical Context Cardiac Power Output Index is a hemodynamic parameter that reflects the amount of hydraulic power generated by the heart per unit of body surface area. It is calculated from Cardiac Power Output, which itself is derived from cardiac output and mean arterial pressure. Because it incorporates both flow and pressure components, the CPO Index provide
Cardiohepatic Index (Hepato-renal Risk Composite): Explanation and Clinical Context The Cardiohepatic Index (CHI) is a composite biomarker integrating hepatic and renal dysfunction to predict adverse outcomes in patients with advanced heart failure. It is calculated using serum bilirubin, creatinine, and sodium levels, reflecting the interplay between hepatic congestion, renal impairment, and systemic hemodynamics. E
— Explanation and Clinical Context This algorithm implements a pragmatic, clinic-level approach to interpreting daily pulmonary artery diastolic (PAD) and (optionally) mean pulmonary artery (PAM) pressure readings obtained from an implanted CardioMEMS™ sensor. The logic uses Merlin.net/Abbott default thresholds when available: a narrow "maintenance" band (PAD ±2 mmHg) where no immediate hemodynamic change is usually
Central Aortic Pressure Index (CAPI): Explanation and Clinical Context The Central Aortic Pressure Index (CAPI) represents the ratio of central aortic pressure to peripheral systolic pressure, reflecting the impact of arterial wave reflections and aortic stiffness on central hemodynamics. It is calculated using peripheral systolic pressure (PSP) and augmentation index (AIx), which represents the contribution of refle
CT Pericardial Thickness Index (PTI): Explanation and Clinical Context The CT Pericardial Thickness Index (PTI) is a standardized measure of pericardial thickness adjusted for body surface area (BSA), providing a more individualized assessment of pericardial remodeling or constriction. Pericardial thickening >4 mm/m² is considered abnormal and may indicate constrictive pericarditis or risk for hemodynamic compromise.
DeFeo Score: Explanation and Clinical Context The DeFeo Score is a validated tool to predict the surgical indication in patients with mitral valve disease. It incorporates functional, structural, and hemodynamic parameters: NYHA functional class, left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF), and pulmonary artery pressure (PAP). Each parameter is assigned points based on t
Calculator mode This tool supports two peer-reviewed approaches: 1) CTEPH segmental scoring (Abozeed et al., 2022): Perfusion Defect (PD) Score = number of segmental perfusion defects (0–18). Optional “Combined Score” adds clot-burden points (anatomic thrombus load) for stronger correlation with hemodynamics. 2) Perfusion Defect Percentage (Kim et al., 2014): Mean extent of perfusion defect across three coronal plane
Explanation and Clinical Context Echocardiography hemodynamics integrates Doppler derived flow, structural measurements, and chamber velocities to estimate stroke volume, cardiac output, filling pressure, and right atrial pressure. LVOT VTI with a measured LVOT diameter yields stroke volume using the continuity principle. Inferior vena cava size and respiratory variation provide an estimate of right atrial pressure a
EPIPHANY Index (Pulmonary Embolism in Cancer): Explanation and Clinical Context The EPIPHANY Index is a prognostic tool developed for patients with active cancer who present with pulmonary embolism. It estimates the risk of 30-day serious complications, including mortality, hemodynamic instability, or need for intensive care interventions. The score integrates clinical parameters available at presentation: oxygen sat
ESC/ERS 2022 Pulmonary Arterial Hypertension Risk Table: Explanation and Clinical Context The ESC/ERS 2022 Risk Table provides a multiparametric assessment model for estimating the 1-year mortality risk in patients with pulmonary arterial hypertension (PAH). It integrates clinical, functional, biomarker, and hemodynamic data to categorize patients into Low (<5%), Intermediate (5–20%), or High (>20%) risk groups. Key
ESCAPE Trial Hemodynamic Congestion Index: Rationale, clinical meaning, and evidence The Hemodynamic Congestion Index (HCI) implemented here is the simple sum of right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP): HCI = RAP (mmHg) + PCWP (mmHg). This index was derived from analyses of the ESCAPE trial dataset and related secondary analyses that examined whether a single composite invasive press
EuroSCORE Calculator EuroSCORE: Comprehensive Explanation and Clinical Context The European System for Cardiac Operative Risk Evaluation, or EuroSCORE, is a validated clinical tool designed to estimate operative mortality in patients undergoing cardiac surgery. It incorporates demographic factors, comorbidities, hemodynamic status, and specific cardiac or surgical risk features. The model was originally derived from
Use this tool to estimate readiness for early or operating-room extubation after adult cardiac surgery. It combines evidence-informed bedside criteria (hemodynamics, gas exchange, bleeding, neurological status) with perioperative predictors reported in the literature to categorize eligibility as Eligible now, Borderline—optimize, or Not eligible now. Fast-Track Extubation (Cardiac Surgery): Explanation and Clinical C
Fontan Failure Index: Explanation and Clinical Context The Fontan Failure Index aims to integrate hemodynamic burden (e.g. elevated central venous pressure, reduced cardiac index) and hepatic injury (represented by liver stiffness by elastography and thrombocytopenia as marker of portal hypertension) to stratify risk of clinical Fontan failure. A higher score suggests greater circulatory stress and end‑organ (hepatic
Hestia Criteria (Outpatient Pulmonary Embolism Treatment Eligibility): Explanation and Clinical Context The Hestia criteria provide a validated, simple tool to identify patients with acute pulmonary embolism who may be safely treated as outpatients. The criteria include hemodynamic stability, absence of active or high-risk bleeding, no need for supplemental oxygen to maintain saturation above 90%, no severe comorbidi
Calculator Explanation and Clinical Context This calculator provides noninvasive echocardiographic estimates that support interpretation of pulmonary artery pressures and pulmonary vascular resistance in clinical practice. Systolic pulmonary artery pressure is estimated from the peak tricuspid regurgitation velocity using the modified Bernoulli equation and an estimate of right atrial pressure. Use this estimate as o
Modified Shock Index (MSI): Explanation and Clinical Context The Modified Shock Index (MSI) is a refinement of the traditional Shock Index (SI), which is defined as the ratio of heart rate (HR) to systolic blood pressure (SBP). MSI replaces SBP with mean arterial pressure (MAP) in the denominator, thereby improving sensitivity and specificity in detecting hemodynamic instability. It is calculated as: MSI = Heart Rate
Paravalvular Leak (PVL) Severity Score: Rationale, Calculations, and Clinical Use This tool consolidates validated catheter-based hemodynamic indices to grade PVL severity immediately after transcatheter aortic valve replacement (TAVR). The core metric is the Aortic Regurgitation Index (ARI), defined as ((DBP − LVEDP) / SBP) × 100. Lower values imply greater diastolic run-off into the LV and more severe PVL. In the s
PARIS Bleeding Risk Score: Comprehensive Explanation and Clinical Context The PARIS Bleeding Risk Score is a validated clinical tool developed to estimate the risk of major bleeding in patients undergoing dual antiplatelet therapy after percutaneous coronary intervention. It incorporates simple bedside variables that reflect age related vulnerability, hemodynamic reserve, underlying comorbidities, and previous bleedi
PDA Severity Score (PDAsc) — Explanation and Clinical Context The PDA Severity Score (PDAsc) is a multivariable echocardiography-based prognostic index developed to quantify early hemodynamic significance of a patent ductus arteriosus in very preterm infants and predict the composite outcome of chronic lung disease or death before discharge. The score combines gestational age, echocardiographic PDA diameter (pulmonar
CRISP Pediatric Cardiac Catheterization Risk Score: Explanation and Clinical Context The CRISP (Catheterization RISk Score for Pediatrics) model is a validated risk tool to predict serious adverse events (SAEs) in pediatric patients undergoing cardiac catheterization. } It incorporates multiple pre‑procedural variables (age, procedure risk level, hemodynamic vulnerability, use of inotropes or mechanical support, emer
Pediatric Pulmonary Hypertension Risk Index: Explanation and Clinical Context The Pediatric Pulmonary Hypertension Risk Index is a validated scoring system to estimate prognosis in children with pulmonary arterial hypertension (PAH). It combines clinical (WHO Functional Class), biomarker (NT-proBNP), exercise capacity (6-minute walk distance), hemodynamic parameters (right atrial pressure and cardiac index) to strati
Penn Classification (Aortic Dissection Outcome): Explanation and Clinical Context The Penn Classification is a prognostic tool for patients with Type A aortic dissection, focusing on the presence of organ malperfusion and circulatory collapse. It stratifies patients into four categories: - Penn Aa: No evidence of ischemia; patient hemodynamically stable. - Penn Ab: Localized organ ischemia; hemodynamically stable. -
Pericardial Effusion Tamponade Index (PETI): Explanation and Clinical Context The Pericardial Effusion Tamponade Index (PETI) is a quantitative echocardiographic score designed to assess the hemodynamic significance of pericardial effusion and predict the risk of cardiac tamponade. It combines the durations of right atrial and right ventricular collapse observed during echocardiography with the maximum width of the p
Pheochromocytoma Perioperative Cardiac Risk Index (P-PCRI): Explanation and Clinical Context This tool estimates the perioperative risk of significant intraoperative hemodynamic instability during adrenalectomy for pheochromocytoma by integrating preoperative clinical and CT-based predictors. Variables include age, BMI, tumor laterality, tumor shape, MAP score, necrosis, planned surgical technique, CHD status, and pr
Explanation and Clinical Context This score is designed for patients resuscitated from cardiac arrest presenting with ST elevation myocardial infarction who achieve return of spontaneous circulation. Early prognostic insight provides clinical value in guiding revascularization timing and post arrest intensive care strategy including ventilation sedation temperature target management and hemodynamic support. Factors i
Postpartum Hemodynamic Stress Index (PHSI): Explanation and Clinical Context The Postpartum Hemodynamic Stress Index (PHSI) is a validated metric to assess cardiovascular stress in the early postpartum period, reflecting the balance between heart rate and mean arterial pressure. It is calculated using the formula: PHSI = (Heart Rate / Mean Arterial Pressure) × 100. Mean Arterial Pressure (MAP) is derived from: MAP =
Pre-op Hemodynamic Optimization Index (PHOI): Rationale, Use, and Evidence The PHOI provided here is a pragmatic composite to help clinicians summarize the patient’s immediate pre-operative hemodynamic state and identify modifiable targets before anesthesia induction. It is not a published or validated score; to our knowledge there is no original “Pre-op Hemodynamic Optimization Index” in the literature. The componen
Pulmonary Capillary Wedge Pressure Calculator: Explanation and Clinical Context Pulmonary capillary wedge pressure is a hemodynamic parameter that reflects left atrial pressure and is widely used as an indirect measure of left ventricular filling pressure. In clinical practice, PCWP plays an essential role in the evaluation of patients with suspected heart failure, assessment of hemodynamic congestion, and differenti
Pulmonary Vascular Resistance Calculator Explanation and Clinical Context Pulmonary vascular resistance describes the afterload that the right ventricle must overcome to eject blood into the pulmonary circulation. It is derived from a hemodynamic relationship that integrates pressure gradients across the pulmonary vasculature and the magnitude of pulmonary blood flow. PVR reflects the degree of vasoconstriction, remo
Pulmonary Vascular Resistance Calculator Explanation and Clinical Context Pulmonary vascular resistance describes the afterload that the right ventricle must overcome to eject blood into the pulmonary circulation. It is derived from a hemodynamic relationship that integrates pressure gradients across the pulmonary vasculature and the magnitude of pulmonary blood flow. PVR reflects the degree of vasoconstriction, remo
Pulmonary-to-Systemic Flow Ratio (Qp/Qs): Explanation and Clinical Context The Pulmonary-to-Systemic Flow Ratio (Qp/Qs) is a hemodynamic index derived from the Fick principle that quantifies the relative blood flow between the pulmonary and systemic circulations. It is essential for the assessment of cardiac shunts such as atrial septal defect (ASD), ventricular septal defect (VSD), and patent ductus arteriosus (PDA)
REVEAL 2.0: Explanation and Clinical Context REVEAL 2.0 is a validated, weighted risk model for pulmonary arterial hypertension (PAH) that integrates demographics, hemodynamics, and biomarkers to estimate 1-year mortality. Each parameter contributes positive or negative points depending on risk direction. The final score stratifies patients into low (0–6), intermediate (7–8), and high (=9) risk. The calculator above
Rockall Upper GI Bleeding Score Explanation and Clinical Context The Rockall score estimates risk of adverse outcome after an acute upper gastrointestinal bleeding episode. It combines three clinical variables available at admission that form the pre endoscopic score and two endoscopic variables that produce the complete score. Age contributes up to two points depending on age group. Hemodynamic status is captured by
Shock Index (HR/SBP Ratio): Explanation and Clinical Context The Shock Index (SI) is a simple, bedside physiological ratio calculated by dividing the heart rate (HR) by the systolic blood pressure (SBP). It serves as a rapid and sensitive indicator of hemodynamic compromise and circulatory shock. A normal Shock Index typically ranges from 0.5 to 0.7. Values above 0.9 are considered abnormal and have been strongly cor
Stroke Volume Index (SVi): Explanation and Clinical Context Stroke Volume Index is a hemodynamic parameter that describes the amount of blood ejected by the left ventricle during each cardiac contraction, adjusted to body surface area. This index refines the interpretation of stroke volume by incorporating patient size, making it a more accurate indicator of forward flow in individuals with significantly different bo
Stroke Volume Index (SVi) for RV Failure Prediction: Explanation and Clinical Context Stroke Volume Index (SVi) is a hemodynamic parameter that represents the stroke volume normalized to body surface area. It is calculated as cardiac output divided by heart rate and then indexed to BSA, providing a load-adjusted measure of cardiac performance. In the context of right ventricular (RV) failure prediction, SVi has been
STRONG-HF Risk Framework — explanation and clinical context This calculator implements a transparent prototype points system that aggregates commonly reported prognostic features relevant to patients hospitalized for acute heart failure (age, hemodynamics at discharge, NT-proBNP, renal function, potassium, LVEF, recent HF hospitalization, and intensity of guideline-directed medical therapy achieved at discharge). It
Swedish PAH Registry Risk Model: Explanation and Clinical Context The Swedish PAH Registry Risk Model is a validated prognostic tool for patients with pulmonary arterial hypertension (PAH), developed from the Swedish Pulmonary Arterial Hypertension Registry (SPAHR). It integrates six key clinical and hemodynamic variables: WHO Functional Class (FC), 6-Minute Walk Distance (6MWD), NT-proBNP, Right Atrial Pressure (RAP
Systolic Pressure Recovery Index (Post-Pulmonary Embolism Healing): Explanation and Clinical Context The Systolic Pressure Recovery Index (SPRI) is a hemodynamic ratio used to evaluate right ventricular and pulmonary arterial recovery after acute pulmonary embolism (PE). It quantifies the degree of pressure normalization across the pulmonary circulation, specifically reflecting how systolic and diastolic pressures re
Target Cardiac Output (CO): Explanation and Clinical Context Target cardiac output represents the estimated cardiac output required to maintain adequate systemic perfusion in relation to an individual's body surface area. The formula uses a standard cardiac index value of 2.2 liters per minute per square meter, which reflects the minimal cardiac index associated with preserved organ perfusion in hemodynamically stabl
Tropical Myocarditis Severity Index (TMSI): Explanation and Clinical Context The Tropical Myocarditis Severity Index (TMSI) is a pragmatic bedside score tailored for use in tropical, resource-limited healthcare settings where myocarditis frequently presents secondary to infections such as dengue, rickettsioses, Chagas disease, and leptospirosis. The index prioritizes clinically accessible variables—hemodynamics, arrh
Explanation and Clinical Context This tool is designed for patients with non ST segment elevation acute coronary syndrome and helps clinicians identify situations in which an immediate invasive strategy with urgent coronary angiography is appropriate. The 2025 American guideline on acute coronary syndromes states that patients with NSTE ACS who have refractory angina or hemodynamic or electrical instability should un
Vaccine-Related Myocarditis Severity Triage Score (VRMST): Explanation and Clinical Context This calculator estimates bedside severity for suspected vaccine-associated myocarditis using routinely available clinical data. The proposed VRMST score prioritizes factors that consistently track with worse short-term outcomes in myocarditis—hemodynamic instability/shock, depressed left ventricular function, malignant ventri