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Timing and indications of surgery in stenotic and regurgitant valvular lesions

Timing and indications of surgery in stenotic and regurgitant valvular lesions. Dr.Deepak Raju. Aortic stenosis. Pathophysiology Assessment of severity Natural history Management strategy Role of exercise test,EBCT Recommendations . Concept of afterload mismatch.

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Timing and indications of surgery in stenotic and regurgitant valvular lesions

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  1. Timing and indications of surgery in stenotic and regurgitantvalvular lesions Dr.DeepakRaju

  2. Aortic stenosis • Pathophysiology • Assessment of severity • Natural history • Management strategy • Role of exercise test,EBCT • Recommendations

  3. Concept of afterload mismatch • Term coined by Ross et al (1976) • Increasing aortic pressure increased LV contractility,LV volume and mass kept constant • At a particular level contractility started decreasing-mismatch b/w afterload and contractile state

  4. AS-pathophysiology • Increasing severity of AS-matched by increasing LV mass and contractility • Compensation by hypertrophy fails to sustain afterload • Clinical afterload mismatch occurs • LV utilizes preload reserve-mechanism by which stroke volume is maintained by increasing preload • Preload reserve is not a good compensatory mechanism in AS(LV on steep portion of diastolic pressure volume loop) • Systolic pump function fails once preload reserve is no longer adequate • Earliest stage of LV dysfunction in severe AS

  5. LV systolic dysfunction • Afterload mismatch and/or impaired contractility • LV diastolic dysfunction • Laplace equation • Stress =pressure .radius/2.wall thickness • Increased wall thickness compensates for pressure overload • Impaired relaxation&altered compliance-Diastolic dysfunction • Atrial booster pump maintains LV filling

  6. Assessment of severity • Jet velocity-reproducible,strongest predictor of clinical outcome • Aortic valve area-continuity equation • Velocity ratio- • suboptimal image of LVOT • effectively indexed for BSA • Ratio <0.25 indicates severe stenosis

  7. Other measures of severity • Stroke work loss • Ratio of mean PG to mean LV pressure • >26% predictive of probability of cardiac death or AVR • Energy loss index • Calculated from aortic valve area and area of aorta at sinotubular junction • Severe AS <0.55 cm2/m2 • Valvulo arterial impedance • Reflects degree of valve obstruction,ventricular response and systemic vascular impedance • survival lower in patients with Zva >4.5 mmHg/ml/m2 (Zeineb et al JACC 2009)

  8. Natural history • Prolonged latent period • Rate of progression of stenosis of moderate severity • Jet velocity 0.3 m/s/yr • Gradient 7 mmHg/yr • Area 0.1 cm2/yr

  9. Asymptomatic adult-AS

  10. Pellikka et al .circulation 2005,622 pts,mean follow up 5.4 yr

  11. Other findings(Pellikka et al ) • Patients with jet velocity >4.5 m/s had greater likelihood of develpoing symptoms(relative risk 1.34) • Incidence of sudden cardiac death was 1% /yr

  12. Asymptomatic patient-AS • Patients with asymptomatic severe AS require frequent monitoring for devt.of symptoms • In a meta analysis of seven studies the risk of sudden cardiac death was found to be 0.4%/yr(375 pts,mean follow up 2.1 yr)

  13. Follow up • Clinical • frequent monitoring for devt of symptoms • every year for mild • 6 mth for moderate and severe • TTE • Every year for severe AS • 1-2 year for moderate AS • 3-5 year for mild AS • Patient education regarding devt of symptoms

  14. Exercise testing • May be considered in asymptomatic patients with unclear symptoms to elicit(IIb) • limited exercise capacity • exercise induced symptoms • Abnormal BP response

  15. Amato et al 2001,Heart 2001 • 66pts,14 mth follow up • Positive stress rest • Horizontal or downsloping ST dep>1 mm (men ) &2mm (women)or upsloping ST>3mm in men • Angina ,near syncope • Ventricular arrhythmia • SBP fails to rise by 20 mmHg • Grp with Abnormal exercise response • 19% symptom free survival at 2 yrs • Normal • 85% symptom free survival at 2 yrs • 6% experienced SCD;all had positive stress test

  16. Das P et al, Eur Heart J,2005 • 125 pts,12 mth follow up • Positive test • Limiting symptoms(chest tightness,breathlessness,dizziness) • Abnormal BP response(BP at peak exercise same or below baseline) • ST dep >2mm • Exercise limiting symptoms independent predictor of outcome • Exercise brought out symptoms in 37% pts • In this group spontaneous symptoms developed in 51% compared to 11% in others

  17. Management strategy • In most asymptomatic patients with aortic stenosis,risk of surgery(3-4% for AVR-STS database) is higher than risk of watchful waiting • Early surgery • older pts to higher mortality(8.8% in >65 yr, US medicare data) • Younger pts-morbidity and mortality of prosthetic valve

  18. Early AVR may be considered • Severe valve calcification • Rapid progression • Increase in jet velocity >0.3 m/s/yr • Decrease in valve area >0.1 cm2 /yr • Expected delays in surgery

  19. Symptomatic AS • Critical point in natural history of AS • Average survival is 2-3 years • High risk of sudden cardiac death • AVR improves symptoms and survival

  20. Ross J Jr, Braunwald E: Aortic stenosis. Circulation 38:61, 1968

  21. Low flow low gradient aortic stenosis • Dobutamine stress echocardiography(IIa) • TransvalvularPG,valve area calculated in baseline and low dose dobutamine stress • Severe AS-fixed valve area,increase in stroke volume and gradient • AS not severe-valve area increases >0.2 cm2 ,increase stroke volume ,no change in gradient • Lack of contractile reserve-increase in stroke volume <20%-poor prognosis with medical or surgical therapy

  22. Cardiac biomarkers • Berger klein et al(circulation 2004) • 130 pts with severe AS • NT-BNP < 80 pmol/L predicted symptom free survival in asymptomatic patients followed up for one year(69% vs 18%)

  23. EBCT • Messika et al (circulation 2004) • Valve calcification assessed by EBCT • Event-free survival at 5 years was 92% Vs 40% comparing grps above and below 500 Agatston units

  24. Recommendations for AVR Class I • Severe AS and symptoms • Severe AS (with or without symptom) need for CABG,valve replacement or aortic surgery • Severe AS and LV systolic dysfunction(EF <50 %) Class IIa • Moderate AS and need for other cardiac surgery

  25. Class II b • asymptomatic severe AS • With abnormal exercise response(devt.ofsymptoms,hypotension) • Likelihood of rapid progression,expected delays at symptom onset • Extremely severe AS(area <0.6cm2,gradient>60mmHg,jet velocity>5 m/s) with expected mortality<1% • Mild AS undergoing CABG,evidence of rapid progression • Not useful for prevention of SCD in asymptomatic severe AS without above criteria

  26. Aortic balloon valvotomy • Class II b • Bridge to surgery in hemodynamically unstable patient who are at high risk for AVR • Palliation in whom AVR cannot be performed

  27. Indications of BAV in adolescents and young adults • Class I • Symptomatic AS(angina,syncope,DOE),PSG>50 mmHg,valve not heavily calcified • Asymptomatic,PSG >60 mmHg • Asymptomatic,PSG >50mmHg,with ST or T wave changes in left precordial leads at rest or with exercise • Class II a • Asymptomatic,PSG > 50mmHg,wants to play competitive sports or planning pregnancy • When possible BAV preferred over surgery in adolescent or young adult

  28. AR-Pathophysiology • AR –volume overload and pressure overload • Volume overload • ↑ EDV • ↑ chamber compliance • Combination concentric and eccentric hypertrophy • Pressure overload • ↑ chamber size- ↑ wall stress-elevates afterload • Preload reserve and compensatory hypertrophy maintain ejection performance-asymptomatic patient

  29. Latent phase of AR, like AS, may last decades • Decompensation • Preload reserve exhausted • Hypertrophy inadequate • Impaired contractility • LV systolic dysfunction-initially reversible-afterload excess • Impaired contractility predominates later-irreversible • Chamber enlargement • Spherical geometry • LV systolic function and ESD-most important predictors of postoperative survival and recovery of LV function

  30. Natural history • Asymptomatic patient with normal LV function • 9 published studies,593 patients,mean follow up of 6.6 yrs • 25% of patients who die or develop LV dysfunction do so before the onset of symptoms • Quantitative evaluation of LV function indispensable

  31. Natural history

  32. End systolic dimension in relation to devt of symptoms,LV Dysfunction or death • Bonow et al,circulation 1991 • ESD>50mm-19% /yr • ESD 40-50 mm-6% /yr • ESD <40- 0%

  33. Survival without surgery in symptomatic patients withAR

  34. Symptomatic patients • Poor outcome with medical therapy • Mortality 10% /yr in patients with angina • Mortality 20% /yr in heart failure

  35. Indications for AVR or aortic valve repair • Class I • Symptomatic severe AR • Asymptomatic • severe AR with LVD(EF<0.50 at rest) • CABG ,valve surgery,aortic surgery • Class II a • Asymptomatic severe AR with severe LV dilatation(EDD>75mm,ESD>55mm)

  36. Class II b • Asymptomatic severe AR with borderline LV dilatation(EDD 70-75,ESD 50-55) • abnormal hemodynamic response to exercise • progressive LV dilatation • Declining exercise tolerance • Moderate AR undergoing CABG or aortic surgery

  37. Bicuspid aortic valve with dilated ascending aorta • Class I • Surgery to repair aortic root or replacement of ascending aorta • Diameter of ascending aorta or root >5cm • Rate of increase in size >0.5 cm/yr • Diameter>4.5 cm undergoing AVR

  38. Mitral stenosis • Narrowing of valve area to < 2.5 cm2 occurs before devt.of symptoms • Symptoms at rest occur when valve area <1.5 cm2 • Developed countries- • Long latent period from RF to symptoms (20-40 years) • A decade from symptom onset to disabling symptoms • Rpted streptococcal infection and recurrent carditis-rapid progression in poor countries

  39. Asymptomatic-10 yr survival-80% • Symptomatic-0-15 % 10 yr survival • Devt of PAH-mean survival <3 years • annual loss of mtral valve area-0.09 cm2

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