Timing and indications of surgery in stenotic and regurgitant valvular lesions

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

7. 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

9. 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)

13. 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

14. Asymptomatic adult-AS

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

16. 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

17. 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)

18. 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

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

20. 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

22. 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

24. 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

25. 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

26. 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

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

28. 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

29. 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%)

30. 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

31. 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

32. 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

35. 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

36. 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

37. 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

38. 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

40. 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

41. Natural history

42. 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%

43. Survival without surgery in symptomatic patients withAR

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

45. 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)

46. 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

48. 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

49. 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

50. 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