{"id":60104,"date":"2017-11-15T17:57:02","date_gmt":"2017-11-15T15:57:02","guid":{"rendered":"https:\/\/wpcalc.com\/?p=60104"},"modified":"2026-10-01T13:17:03","modified_gmt":"2026-10-01T10:17:03","slug":"aortic-valve-area","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/medical\/aortic-valve-area\/","title":{"rendered":"Aortic Valve Area Calculator"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Aortic Valve Area<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"60104\" data-favorite-title=\"Aortic Valve Area\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/medical\/aortic-valve-area\/\" data-favorite-excerpt=\"Estimate aortic valve area from LVOT diameter, LVOT VTI and aortic valve VTI using the continuity equation. Enter the three echocardiographic measurements to get CSA, stroke volume and AVA in cm\u00b2.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-heartbeat\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/en\/medical\/aortic-valve-area\/\" method=\"POST\" class=\"calculator\" id=\"calculator-60104\" data-post=\"60104\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">LVOT Diameter<\/label><div class=\"term\">D<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"lvot_diameter\" id=\"field-1\" aria-describedby=\"calc-unit-1\" placeholder=\"Diameter\" step=\"any\" value=\"2\"\/><div class=\"unit\" id=\"calc-unit-1\">cm<\/div><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">LVOT (VTI)<\/label><div class=\"term\">LVOT<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"lvot_vti\" id=\"field-2\" aria-describedby=\"calc-unit-2\" placeholder=\"LVOT VTI\" step=\"any\" value=\"20\"\/><div class=\"unit\" id=\"calc-unit-2\">cm<\/div><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-3\">Aortic Valve VTI<\/label><div class=\"term\">AV<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"aortic_valve_vti\" id=\"field-3\" aria-describedby=\"calc-unit-3\" placeholder=\"Aortic VTI\" step=\"any\" value=\"40\"\/><div class=\"unit\" id=\"calc-unit-3\">cm<\/div><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"60104\">Calculate<\/button><button type=\"reset\">Reset<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calculate automatically<\/label><small>If enabled, the result will update automatically when you change any value.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Your Results<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>CSA<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"cm\u00b2\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-2\"><span class=\"field-title\"><span>SV<\/span><\/span><span class=\"field-value\" id=\"result-2\" data-unit=\"cm\u00b3\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-3\"><span class=\"field-title\"><span>Aortic Valve Area<\/span><\/span><span class=\"field-value\" id=\"result-3\" data-unit=\"cm\u00b2\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copy link to this calculation<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Leave a Comment<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"60104\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">How did this result make you feel?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Like <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">Helpful <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confused <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Disappointed <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Inaccurate <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>Aortic Valve Area Formula (Continuity Equation)<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">Formula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ AVA = \\frac{CSA_{LVOT} \\times VTI_{LVOT}}{VTI_{AV}} = \\frac{0.785 \\times D^2 \\times VTI_{LVOT}}{VTI_{AV}} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(D\\) \u2014 LVOT diameter, measured in the parasternal long-axis view (cm)<\/li>\n<li>\\(VTI_{LVOT}\\) \u2014 velocity\u2013time integral of flow in the left ventricular outflow tract (cm)<\/li>\n<li>\\(VTI_{AV}\\) \u2014 velocity\u2013time integral of flow across the stenotic aortic valve (cm)<\/li>\n<li>\\(AVA\\) \u2014 aortic valve area (cm\u00b2)<\/li>\n<\/ul>\n<p>The continuity equation states that, in the absence of regurgitation or shunts, the volume of blood passing through the LVOT equals the volume passing through the aortic valve. Since flow volume equals cross-sectional area times VTI, the aortic valve area can be derived by comparing the two sites. The calculator also reports two intermediate values:<\/p>\n<ul>\n<li>LVOT cross-sectional area: \\(CSA = 0.785 \\times D^2\\) (cm\u00b2), where 0.785 approximates \\(\\pi \/ 4\\)<\/li>\n<li>Stroke volume: \\(SV = CSA \\times VTI_{LVOT}\\) (cm\u00b3, i.e. mL)<\/li>\n<\/ul>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-459\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Aortic Valve Area \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a patient with suspected aortic stenosis has an LVOT diameter of 2 cm, an LVOT VTI of 20 cm and an aortic valve VTI of 40 cm on Doppler echocardiography.<\/p>\n<p>\\[ CSA = 0.785 \\times 2^2 = 3.14\\ \\text{cm}^2 \\]<\/p>\n<p>\\[ SV = 3.14 \\times 20 = 62.8\\ \\text{cm}^3 \\]<\/p>\n<p>\\[ AVA = \\frac{62.8}{40} = 1.57\\ \\text{cm}^2 \\]<\/p>\n<p><strong>Result:<\/strong> LVOT cross-sectional area = 3.14 cm\u00b2, stroke volume = 62.8 mL, aortic valve area = 1.57 cm\u00b2, consistent with mild aortic stenosis.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Measure the <strong>LVOT Diameter<\/strong> in the parasternal long-axis view in mid-systole, at the level of the aortic annulus, and enter it in cm.<\/li>\n<li>Obtain the <strong>LVOT (VTI)<\/strong> with pulsed-wave Doppler in the apical five-chamber view, placing the sample volume just proximal to the aortic valve, and trace the spectral envelope to get the VTI in cm.<\/li>\n<li>Obtain the <strong>Aortic Valve VTI<\/strong> with continuous-wave Doppler from the window that yields the highest-velocity signal (apical, suprasternal or right parasternal), and enter it in cm.<\/li>\n<li>Read the results: <strong>CSA<\/strong> (cm\u00b2), <strong>SV<\/strong> (cm\u00b3) and <strong>Aortic Valve Area<\/strong> (cm\u00b2).<\/li>\n<li>Interpret the AVA together with the dimensionless severity index (the ratio \\(VTI_{LVOT}\/VTI_{AV}\\)), mean transvalvular gradient, jet velocity and left ventricular function.<\/li>\n<\/ol>\n<h2>What is the aortic valve area and why it matters<\/h2>\n<p>The aortic valve area (AVA) is the effective opening through which the left ventricle ejects blood into the aorta. In <strong>aortic stenosis<\/strong>, the valve narrows \u2014 usually due to calcific degeneration, a bicuspid valve or rheumatic disease \u2014 and the heart must generate higher pressures to maintain cardiac output. The AVA is one of the cornerstones of stenosis grading, alongside the mean pressure gradient and peak jet velocity.<\/p>\n<p>Because direct planimetry of the aortic valve is often difficult with transthoracic echocardiography, the <strong>continuity equation<\/strong> is used instead. It rests on the principle of conservation of mass: the stroke volume flowing through the LVOT must equal the stroke volume crossing the stenotic valve. The LVOT is assumed to be circular, so its cross-sectional area is \\(0.785 \\times D^2\\). Multiplying this area by the LVOT VTI gives the stroke volume, and dividing that by the aortic valve VTI gives the valve area.<\/p>\n<p>Typical interpretation ranges for adults are: <strong>normal<\/strong> valve area 2.5\u20133.5 cm\u00b2, <strong>mild<\/strong> stenosis 1.5\u20132.0 cm\u00b2, <strong>moderate<\/strong> stenosis 1.0\u20131.5 cm\u00b2, and <strong>severe<\/strong> stenosis below 1.0 cm\u00b2. Severe stenosis becomes clinically decisive when it coincides with symptoms (angina, syncope, dyspnoea) or a mean gradient above 40 mmHg. Decisions about valve intervention are never made on the AVA alone but on the full clinical picture.<\/p>\n<p>Since stroke volume is computed along the way, this calculator also complements other hemodynamic assessments such as <a href=\"https:\/\/wpcalc.com\/en\/medical\/ejection-fraction\/\">ejection fraction<\/a> and <a href=\"https:\/\/wpcalc.com\/en\/medical\/cardiac-output\/\">cardiac output by the Fick method<\/a>. For a broader cardiovascular work-up you may also find the <a href=\"https:\/\/wpcalc.com\/en\/medical\/mean-arterial-pressure\/\">mean arterial pressure calculator<\/a> useful.<\/p>\n<h2>Reference values by stenosis severity<\/h2>\n<table>\n<thead>\n<tr>\n<th>Severity<\/th>\n<th>Aortic valve area (cm\u00b2)<\/th>\n<th>AVA index (cm\u00b2\/m\u00b2)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Normal<\/td>\n<td>2.5\u20133.5<\/td>\n<td>&gt; 0.85<\/td>\n<\/tr>\n<tr>\n<td>Mild stenosis<\/td>\n<td>1.5\u20132.0<\/td>\n<td>0.60\u20130.85<\/td>\n<\/tr>\n<tr>\n<td>Moderate stenosis<\/td>\n<td>1.0\u20131.5<\/td>\n<td>0.50\u20130.60<\/td>\n<\/tr>\n<tr>\n<td>Severe stenosis<\/td>\n<td>&lt; 1.0<\/td>\n<td>&lt; 0.50<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Assumptions, limitations and practical tips<\/h2>\n<ul>\n<li><strong>The LVOT is assumed circular.<\/strong> Because the diameter is squared, small measurement errors are amplified: a 1 mm error in a 20 mm LVOT changes the AVA by roughly 10%. Measure the diameter at the same level as the pulsed-wave sample volume, from inner edge to inner edge in mid-systole, over several beats.<\/li>\n<li><strong>No significant aortic or mitral regurgitation.<\/strong> The continuity equation assumes all LVOT flow crosses the aortic valve. Significant regurgitation or intracardiac shunts invalidate the calculation.<\/li>\n<li><strong>Accurate VTI tracing matters.<\/strong> Trace the outer edge of the dense spectral envelope. Use multiple windows for the aortic signal to capture the true maximal velocity, and average LVOT measurements over at least three beats (five to ten in atrial fibrillation).<\/li>\n<li><strong>Low-flow, low-gradient states.<\/strong> In patients with reduced stroke volume, the AVA may suggest severe stenosis despite a low gradient. Dobutamine stress echocardiography or other confirmatory imaging should be considered.<\/li>\n<li><strong>Index for body size.<\/strong> In very small or large patients, the indexed AVA (cm\u00b2\/m\u00b2 of body surface area) gives a fairer assessment.<\/li>\n<li>This calculator is intended for educational and clinical-support use by trained professionals; results should always be interpreted in the context of the full echocardiographic and clinical evaluation, not in isolation.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Estimate aortic valve area from LVOT diameter, LVOT VTI and aortic valve VTI using the continuity equation. Enter the three echocardiographic measurements to get CSA, stroke volume and AVA in cm\u00b2.<\/p>\n","protected":false},"author":70,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[8],"tags":[15],"class_list":["post-60104","post","type-post","status-publish","format-standard","hentry","category-medical","tag-cardiology"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/60104","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/users\/70"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=60104"}],"version-history":[{"count":3,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/60104\/revisions"}],"predecessor-version":[{"id":66300,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/60104\/revisions\/66300"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=60104"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=60104"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=60104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}