Scherman J Chris Barnard Division of Cardio-Thoracic Surgery

1. The Aortic valve and Cardiac Failure Aortic stenosis Scherman J Chris Barnard Division of Cardio-Thoracic Surgery U n i v e r s i t y o f C a p e T o w n Hannes Meyer Symposium 12 April 2008

2. Aortic valve and Cardiac Failure Tight AS and impaired LVEF - Options and outcomes • Prognostic indicators: Stenosis and pseudo-stenosis • Associated coronary artery disease • The role of MIBI scanning •

3. Pathophysiology of AS¹ Afterload LV wall stress Concentric LVH Symptomatic patients: mortality rates up to 90% in a 2 year natural history of the disease² • ¹Cardiac Surgery in the adult 2008: 825-840. Mihaljevic T, Sayeed M, Stamou Set al ²Ann Thor Surg 2004; 78: 90-95. Sharma UC, Barenbrug B, Pokharel S et al

4. Aortic valve and Cardiac Failure What is tight/severe AS?¹ • • Transvalvular gradient (TVG) • Aortic valve area (AVA) • Maximum Aortic velocity > 40mm Hg < 1cm² > 4m/s Why measure stenosis severity? • ¹Circulation 2006; 114; e84-e231. Bonow RO et al

5. Surgery for severe AS and low LVEF Historically: Impaired LVEF is considered a predictor of poor outcome after AVR • Variation in long term outcomes¹ • Patient Categories² • • High gradient • Low gradient (‘afterload mismatch’) • Low gradient (cardiomyopathy) ¹Eur J Cardiothorac Surg 2006; 29: 133-138. Chukwuemeka A, Rao V, Armstrong S et al ²Circulation 2007; 115;2799-2800. Carabello BA.

6. Severe AS and low LVEF: Prognostic indicators Dobutamine stress echocardiography • • True aortic stenosis • Pseudo-stenosis Preoperative LVESVI¹ ≤ 90ml/m² • • cardiac mortality & LV recovery Preoperative LVESDI² ≤ 27.5mm/m² • Role of valve choice in LV mass reduction • ¹Eur J Cardiothorac Surg 2003; 24: 879-885. Tarantini G, Bujo P, Scognanamiglio R et al ²Int J Cardiol Article in press Ding W, Lam Y, Kaya MG et al

7. Options for Aortic valve replacement • Mechanical AVR • Bioprosthesis • Homograft • Autograft • Aortic valve repair • Percutaneous balloon valvotomy • Apico-aortic valved conduit • Percutaneous transcatheter valve insertion • Transapical AVR

8. Options for Aortic valve replacement • Considerations • Durability and Structural valve deterioration (Age) • Risk of thromboembolism and haemorrhagic complications • Patient preference • Pregnancy

9. Major criteria for Aortic valve selection Class I 1. A mechanical prosthesis is recommended for AVR in patients with a mechanical valve in the mitral or tricuspid position. (Level of Evidence: C) 2. A bioprosthesis is recommended for AVR in patients of any age who will not take warfarin or who have major medical contraindications to warfarin therapy. (Level of Evidence: C) Class IIa 1. Patient preference is a reasonable consideration in the selection of aortic valve operation and valve prosthesis. A mechanical prosthesis is reasonable for AVR in patients under 65 years of age who do not have a contraindication to anticoagulation. A bioprosthesis is reasonable for AVR in patients under 65 years of age who elect to receive this valve for lifestyle considerations after detailed discussions of the risks of anticoagulation versus the likelihood that a second AVR may be necessary in the future. (Level of Evidence: C) 2. A bioprosthesis is reasonable for AVR in patients aged 65 years or older without risk factors for thromboembolism. (Level of Evidence: C) 3. Aortic valve re-replacement with a homograft is reasonable for patients with active prosthetic valve endocarditis. (Level of Evidence: C) Class IIb A bioprosthesis might be considered for AVR in a woman of childbearing age. (Level of Evidence: C) ACC/AHA Guidelines for the management of patients with valvular heart disease, 2006

10. Mechanical Aortic valve prosthesis Caged ball Durable Easy insertion, redo Anticoagulation Tilting disk Bileaflet

11. Stented and Non-stented bioprosthesis • Low thromboembolism rates without Warfarin Freedom from structural valve deterioration is age-specific • • Stented bioprosthesis vs Porcine Pericardial • Stentless bioprosthesis • Enhanced hemodynamic efficiency • Less TVG •

12. Stented and Non-stented bioprosthesis • Low thromboembolism rates without Warfarin Freedom from structural valve deterioration is age-specific • Impact of age on structural valve dysfunction ¹Ann Thorac Surg 2001: 72; 753-757, Banbury MK, Cosgrove DM, White JA et al.

13. Stented and Non-stented bioprosthesis • Low thromboembolism rates without Warfarin Freedom from structural valve deterioration is age-specific • • Stented bioprosthesis vs Porcine Pericardial • Stentless bioprosthesis • Enhanced haemodynamic efficiency • Less TVG •

14. Aortic valve Homografts • Excellent haemodynamic efficiency • Low risk of thromboembolism • Structural valve deterioration • Potential difficult redo surgery

15. Pulmonary valve autotransplantation • Advantages Excellent hemodynamic efficiency Low risk of thrombo-embolism Growth potential Low risk of endocarditis Disadvantages • 2 Valves at risk More complex surgery Potential aortic root dilatation Homograft – Structural valve deterioration

16. Aortic valve repair Limited expertise • High rates of restenosis and recalcification •

17. Percutaneous balloon aortic valvotomy Class IIb 1. Aortic balloon valvotomy might be reasonable as a bridge to surgery in hemodynamically unstable adult patients with AS who are at high risk for AVR. (Level of Evidence: C) 2. Aortic balloon valvotomy might be reasonable for palliation in adult patients with AS in whom AVR cannot be performed because of serious comorbid conditions. (Level of Evidence: C) Class III Aortic balloon valvotomy is not recommended as an alternative to AVR in adult patients with AS; certain younger adults without valve calcification may be an exception. (Level of Evidence: B) Bridge to surgery Comorbidities Not a alternative to AVR ACC/AHA Guidelines for the management of patients with valvular heart disease, 2006

18. LV-to-Descending Aortic shunt • Favourable short term outcomes • Unknown long term hemodynamics and complication rates

19. Percutaneous transcatheter valve insertion ¹J Am Coll Cardiol. 2004; 43: 698-703. Cribier A, Eltchaninoff H, Tron C et al.

20. Transapical Aortic valve implantation Cribier Edwards prosthesis: Balloon expandible pericardial xenograft Transapical aortic valve implantation Eur J Card Surg. 2008. Article in press. Walther T, Falk V, Kempfert J et al

21. Management strategy for severe AS ¹Circulation 2006; 114; e84-e231. Bonow RO et al

22. AS associated with coronary artery disease In patients with AS, prevalence of CAD is 40-50% in those with typical angina, 25% in those with atypical chest pain, and 20% in those without chest pain¹ • In patients with severe AS, angina is a common symptom in young patients with normal coronaries. CAD is a common finding in older symptomatic men with AS • Angina is a less specific indicator of CAD in patients with valvular heart disease than in the general population • ¹Circulation 2006; 114; e84-e231. Bonow RO et al

23. Outcomes: AS associated with CAD Coexisting CAD is a complex risk factor for premature death after operation • Concomitant CABG carries a higher earlier mortality (6.3%) than either AVR alone (3.9%) or CABG alone (2.8%) • Patients with both aortic valve and CAD who undergo only AVR have lower survival than patients who undergo concomitant CABG • The number of bypass grafts does not adversely affect survival. The patient’s preoperative risk factors is a better predictor of outcome¹ • ¹Ann Thorac Surg 2007; 83: 969-978. Kobayashi KJ, Williams JA, Nwakanma L et al

24. AS associated with coronary artery disease Indications for catheterization • Class I 1. Coronary angiography is indicated before valve surgery (including infective endocarditis) or mitral balloon commissurotomy in patients with chest pain, other objective evidence of ischemia, decreased LV systolic function, history of CAD, or coronary risk factors (including age). Patients undergoing mitral balloon valvotomy need not undergo coronary angiography solely on the basis of coronary risk factors. (Level of Evidence: C) 2. Coronary angiography is indicated in patients with apparently mild to moderate valvular heart disease but with progressive angina (Canadian Heart Association functional class II or greater), objective evidence of ischemia, decreased LV systolic function, or overt congestive heart failure. (Level of Evidence: C) 3. Coronary angiography should be performed before valve surgery in men aged 35 years or older, premenopausal women aged 35 years or older who have coronary risk factors, and postmenopausal women. (Level of Evidence: C) History Symptoms Risk Factors Age ACC/AHA Guidelines for the management of patients with valvular heart disease, 2006

25. When to do CABG in patients undergoing AVR Treatment of CAD at the time of AVR • Class I Patients undergoing AVR with significant stenoses (greater than or equal to 70% reduction in luminal diameter) in major coronary arteries should be treated with bypass grafting. (Level of Evidence: C) Class IIa 1. In patients undergoing AVR and coronary bypass grafting, use of the left internal thoracic artery is reasonable for bypass of stenoses of the left anterior descending coronary artery greater than or equal to 50% to 70%. (Level of Evidence: C) 2. For patients undergoing AVR with moderate stenosis (50% to 70% reduction in luminal diameter), it is reasonable to perform coronary bypass grafting in major coronary arteries. (Level of Evidence: C) Significant stenosis Moderate stensosis ACC/AHA Guidelines for the management of patients with valvular heart disease, 2006

26. When to do AVR in patients undergoing CABG Class I AVR is indicated in patients undergoing CABG who have severe AS who meet the criteria for valve replacement. (Level of Evidence: C) Class IIa AVR is reasonable in patients undergoing CABG who have moderate AS (mean gradient 30 to 50 mm Hg or Doppler velocity 3 to 4 m per second). (Level of Evidence: B) Class IIb AVR may be considered in patients undergoing CABG who have mild AS (mean gradient less than 30 mm Hg or Doppler velocity less than 3 m per second) when there is evidence, such as moderate severe valve calcification, that progression may be rapid. (Level of Evidence: C) Severe aortic stenosis Moderate stensosis Mild stensosis ACC/AHA Guidelines for the management of patients with valvular heart disease, 2006

27. Cardiac Radionuclide Imaging Assessment of LV Function Assessment of CAD (MIBI) Assessment of myocardial viability • Screening for CAD in patients with severe aortic stenosis with angina • Coronary angiography remains the gold standard in the preoperative work-up of patients with aortic stenosis presenting with angina¹ • ¹Circulation. 2006; 108; 1404 – 1418. Klocke FJ, Baird MJ, Lorell BH et al

28. Conclusion Most patients with AS and depressed LVEF will benefit from AVR • Favourable Prognostic factors: • • True aortic stenosis • LVESVI ≤ 90ml/m² • LVESDI ≤ 27.5mm/m² • Replacement valves with low TVG’s Severe AS with associated mod-severe CAD: Ø for both CAD with associated severe AS: Ø for both CAD with associated mild-mod AS: Ø for CAD, Ø for AS reasonable • Cardiac radionuclide imaging – some use in screening, but not the gold standard •

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