SHA24/076003

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!

ď&#x201A;&#x17E; ď&#x201A;&#x17E;

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?

ď&#x201A;&#x17E; ď&#x201A;&#x17E;

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