Stress Echocardiography in Valvular Heart Disease Assessment GHA 10 / SHA 24 Joint Scientific Conference 13th-16th February 2013 Riyadh, Saudi Arabia
J Amer Coll cardiol 2008;52(13):e1-142
Eur Heart J 2012;33(19)2451-1496
Acute Response to Dynamic Exercise
Marked increase in CO Marked increase in heart rate Marked increase in SV Marked increase in SBP Mild increase in mean arterial pressure Mild decrease in diastolic BP Marked decrease in total systemic resistance No change in pulmonary vascular resistance Mild increase in mean PA pressure
Exercise testing in Valve Disease Technical Setting! Exercise treadmill More physiological, achieve higher work-load Imaging restricted to baseline and post exercise Need for rapid acquisition of images within 1-2 minutes Bicycle Supine: Recommended Upright Pharmacological Dobutamine: Up to 20 µgm/kg/min Not preferred: Symptoms and BP response
Exercise in Asymptomatic Aortic Stenosis Parameters Checked
Total exercise time Maximum work load Peak heart rate Peak BP Reason for stopping Doppler: Mean gradientAO TVILVOT and TVIAO
What Can Exercise Testing Do?
Identify limited exercise capacity Identify abnormal BP response Hypotension < 20 mm Hg increase in SBP
Identify exercise induced symptoms Provide basis for advice about physical activity Provide information on prognosis
Abnormal Exercise Test Criteria
Symptoms Angina Dyspnoea Syncope / near syncope
Fall in BP or < 20 mm Hg rise in systolic BP during exercise < 80% of normal expected level of exercise > 2 mm ST-segment depression during exercise not attributable to other causes Ventricular arrhythmia
Prognosis!
Abnormal BP response Hypotension Failure to increase SBP
Poor prognostic findings Symptom free survival at 2 years 19% (vs
85%) Annual mortality rate 1.2 % Amato et al. Heart 2001;86:381-6
Independent Predictors of Cardiac Events Increase in mean gradient ≥ 18 mm Hg during exercise AVA < 0.75 cm2 Abnormal exercise test Angina Dyspnea ≥ 2 mm ST-segment depression Fall on systolic BP < 20 mm HG rise in systolic BP
Lancellotti et al. Circulation 2005;112 (Suppl I):I-377-I-382
Aortic Stenosis with LV Dysfunction
Impaired EF of < 20% Mean gradient of 35 mm Hg, with estimated AVA of 0.8 cm2
Severe Aortic Stenosis Definition
Mean gradient > 40 mm HG Normal cardiac output Normal LV systolic function Valve area < 1.0 cm2 * Valve area index < 0.6 cm2 / m2
Bonow et al. J Am Coll Cardiol 2008;52:e1-142
Low Gradient Low Flow Aortic Stenosis Definition At least two of the following haemodynamic Measurements:
Effective AVA
< 1.0 cm2 (0.7-1.2) Mean Trans Ao Gradient < 30 mm Hg LV Ejection fraction < 40%
Low Gradient Low Flow Aortic Stenosis
True aortic stenosis Inability of LV to cope with the greatly increased
after-load Inability of LV to generate high gradient due to low SV
Pseudo-severe aortic stenosis Valve mildly stenotic Concomitant cardiomyopathy with insufficient
force to open the valve
Low Gradient Low Flow Aortic Stenosis Implications!
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True Aortic stenosis: Likely to benefit from AVR Pseudo-severe aortic stenosis: Unlikely to benefit from AVR
Aortic Stenosis: Low Gradient AS With LV Dysfunction Low gradient LV Dysfunction
Severe end-stage AS 2ry LV systolic dysfunction
Mild AS Severe myocardial dysfunction
Aortic Stenosis: Low Gradient AS With LV Dysfunction Resting Hemodynamics: HR, BP, CO, VTILVOT, VTIAO and
gradient, AVA Dobutamine at 5 u / kg / min Increase by 5 u / kg / min every 5-8 min to maximum of 20: maximum inotropic without chronotropic response Repeat hemodynamics each time
Aortic Stenosis: Low Gradient AS With LV Dysfunction Low gradient LV Dysfunction Dobutamine Stress
CO Gradient > 40 mm Hg Fixed AVA
Severe AS
Mild or CO Gradient Increased AVA > 0.3 cm2 Myocardial Dysfunction
Contractile Reserve Definition With dobutamine Stress Test Improvement in trans-valvular flow rate Improvement in SV > 20% Increase of > 20 mm Hg in the mean transvalvular pressure gradient Increase in peak velocity of > 0.6 m/s
Contractile Reserve
Strong predictor of peri-operative mortality: 32% vs 5%* Strong predictor of long term survival Should not be used to preclude AVR: medical therapy is associated with3-year survival of < 15% Does not predict post operative functional class
* Monin et al. Circulation 2003;108:319-324
Quere et al. Cirulation 2006;113:1738-1744
Group I = With Contractile Reserve Group II = Without Contractile Reserve
Median value
Individual Patients
Aortic Stenosis Impaired LV Function
VTILVOT = 12 cm
Baseline
VTILVOT = 14.8 cm
At 20 Âľg Dobutamine
Aortic Stenosis Impaired LV Function
VTIao = 50 cm
Baseline Area = 0.68 cm2
VTIav = 58 cm
At 20 Âľg Dobutamine Area = 0.7 cm2
Aortic Stenosis Impaired LV Function
Exercise Testing in Aortic Regurgitation What Can a Stress Test Do?
Useful to detect early latent systolic dysfunction Provide prognostic information Assess situation in patients with symptoms but mild to moderate disease
Exercise Testing in Aortic Regurgitation Parameters
LVESV at rest and with exercise LVEDV at rest and with exercise EF at rest and with exercise Annular systolic velocities and indices of longitudinal function could be measured by tissue Doppler
Vinereanu et al. Heart 2001;85:30-60
Exercise Testing in Aortic Regurgitation Guidelines! Class IIA / Level of Evidence B Exercise stress testing for chronic AR is reasonable for assessment of functional capacity and symptomatic response in patients with a history of equivocal symptoms Exercise stress testing for chronic AR is reasonable for the evaluation of symptoms and functional capacity before participation in athletic activities Class IIB / Level of evidence B Exercise testing in patients with radionuclide angiography may be considered for assessment of LV function in asymptomatic or symptomatic patients with chronic AR
Exercise Testing in Asymptomatic Mitral Stenosis Who Needs Stress Echo?
Significant MS (MVA < 1.5 cm2) especially in sedentary patients Patients with apparently non-significant MS but with limiting symptoms Follow-up of patients post commissurotomy and MBV because of re-stenosis
Exercise Testing in Asymptomatic Mitral Stenosis What Test?
Dynamic exercise is more physiological Upright treadmill Supine bicycle Dobutamine stress echo
Doppler echocardiography Should not stop treatment
Exercise Testing in Asymptomatic Mitral Stenosis Parameters
Exercise tolerance Trans-mitral mean pressure gradient TR velocity to estimate PA systolic pressure MVA more accurately estimated by the CE rather than the pressure half-time
Braveman et al. Am J cardiol 1991;68:1485-1490 Nakatani et al. Circulation 1988;77:78-85
Exercise Testing in Asymptomatic Mitral Stenosis What to Look For!
Objective limitation of exercise tolerance Rise in mitral mean pressure gradient > 15 mm Hg Rise of PA systolic pressure > 60 mm Hg
Exercise Testing in Asymptomatic Mitral Stenosis Guidelines! Class I / Level of Evidence C ď&#x201A;&#x17E; Echocardiography should be performed for assessment of the hemodynamic response of the mean gradient and pulmonary artery pressure by exercise Doppler echocardiography in patients with MS when there is discrepancy between resting Doppler echcardiographic findings, clinical findings, symptoms and signs
Exercise Testing in Asymptomatic Mitral Stenosis Guidelines for Management! Class I / Level of Evidence C ď&#x201A;&#x17E; Percutaneous MBV is effective for asymptomatic patients with moderate or severe MS and valve morphology that is favorable who have PHT (PASP > 50 mm Hg at rest or > 60 mm HG with exercise in the absence of LA thrombus or moderate to severe MR
Exercise Testing in Symptomatic Mitral Stenosis Guidelines for Management! Class IIb / Level of Evidence C ď&#x201A;&#x17E; Percutaneous MBV may be considered for symptomatic patients (NYHA functional class II, III, or IV) with MVA > 1.5 cm2 if there is evidence of hemodynamically significant MS based on PASP > 60 mm Hg, PA wedge pressure > 25 mm Hg , or mean MV gradient > 15 mm hg during exercise
Asymptomatic Mitral Stenosis!
750058
Transmitral Gradients At Rest: Rate 55 bpm
Post Exercise: Rate 116 bpm
Gradients: 16 and 8 mm Hg
Gradients: 27 and 20 mm Hg
TR Velocity At Rest: Rate 55 bpm
Post Exercise: Rate 116 bpm
PASP = 38 + RAP
PASP = 109 + RAP
Exercise Testing in Organic Mitral Regurgitation What Can Stress Echo Do?
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Unmask latent LV contractile reserve Predict post-operative EF
Exercise Testing in Organic Mitral Regurgitation Parameters
Exercise tolerance Exertional symptoms LVESV at rest and with exercise LVEDV at rest and with exercise EF at rest and with exercise TR velocity to estimate PA systolic pressure Change in severity of MR
Exercise Testing in Organic Mitral Regurgitation Guidelines for Management! Class IIa / Level of Evidence C ď&#x201A;&#x17E; Exercise Doppler echocardiography is reasonable in asymptomatic patients with severe MR to assess exercise tolerance and effect of exercise on PASP and MR severity ď&#x201A;&#x17E; Elective surgery might be proposed in patients with a high likelihood of valve repair and exercise-induced systolic PASP > 60 mm hg
Left ventricular function after valve repair for chronic mitral regurgitation: predictive value of preoperative assessment of contractile reserve by exercise echocardiography DY Leung, BP Griffin, WJ Stewart, DM Cosgrove 3rd, JD Thomas, and TH Marwick
CONCLUSIONS: In minimally symptomatic patients with mitral regurgitation, latent ventricular dysfunction may be indicated by a limited contractile reserve, manifest at exercise as an inadequate increase in ejection fraction and a larger end-systolic volume. These variables may also be used to predict left ventricular function after repair.
Asymptomatic Mitral Regurgitation
Asymptomatic Mitral Regurgitation At Rest: Rate 60 bpm
Post Exercise: Rate 89 bpm
Gradients: 14 and 4 mm Hg
Gradients: 19 and 11 mm Hg
Asymptomatic Mitral Regurgitation At Rest: Rate 60 bpm
PASP = 22 + RAP
Post Exercise: Rate 134 bpm
PASP = 76 + RAP