ACC 2006 ANNUAL SESSION HIGHLIGHTS
Valvular Heart Disease/Cardiac Surgery
Shahbudin H. Rahimtoola, MB, FRCP, MACP, MACC, DSc (Hon)*
Griffith Center, Division of Cardiovascular Medicine, Department of Medicine, LAC + USC Medical Center, Keck School of Medicine at University of Southern California, Los Angeles, California.
* Address correspondence to: Dr. Shahbudin H. Rahimtoola, University of Southern California, 2025 Zonal Avenue, Los Angeles, California 90033.
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Abbreviations and Acronyms
| | AS = aortic stenosis | | AV = atrial valve | | AVC = aortic valve calcification | | AVR = aortic valve replacement | | EVEREST = Endovascular Valve Edge-to-Edge Repair Study | | IE = infective endocarditis | | IMR = ischemic mitral regurgitation | | MESA = Multi-Ethnic Study of Atherosclerosis | | MetS = metabolic syndrome | | MR = mitral regurgitation | | MV = mitral valve | | PHV = prosthetic heart valve | | VHD = valvular heart disease |
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This review contains the conclusions from the published abstracts with or without additions.
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Mortality and morbidity attributable to valvular heart disease (VHD)
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The annual National Hospital Discharge Survey showed that VHD is a significant cause of morbidity and mortality in the U.S. Mortality and hospitalization for VHD have increased since 1980, especially in women and the elderly (1). The causes of these trends and the implications for clinical and public health practice deserve further study.
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Newer issues in valve disease
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Immunochemistry studies were performed to study cellular mechanisms (2). These show that VHD in humans involves an endochondral bone process that is expressed as cartilage in the mitral valve (MV) and bone in the atrial valve (AV). This process may be regulated by the Lrp5 (low-density lipoprotein receptor pathway; a chondrocytic differentiation pathway), which may contribute to the pathophysiology of valve degeneration.
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Aortic stenosis (AS)
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- 1 The Euro Heart Survey (3) showed that: 1) women with severe AS present at an older age and with more severe symptoms, whereas men have more frequent comorbidity and coronary disease; 2) the severity of AS did not differ according to gender when considering indexed valve area; 3) gender had no impact on the decision to operate, even when adjusting for differences in patient characteristics; and 4) one-year survival tended to be higher in women.
- 2 The hypothesis that aortic valve replacement (AVR) prevents arteriovenous malformation bleeding in AS patients was not supported in this study (4).
- 3 In patients with severe AS, comorbidities, particularly renal dysfunction, significantly impacted long-term outcome (5). Early diagnosis and treatment of comorbidities may help to improve the prognosis in this patient population.
- 4 The combination of high levels of high sensitivity C-reactive protein indicating systemic inflammation plus low fetuin-A serum levels indicating systemic calcification inhibitor deficiency were associated with pronounced aortic valve calcification (6).
- 5 In the Multi-Ethnic Study of Atherosclerosis (MESA) cohort, metabolic syndrome (MetS) and diabetes were associated with an increased risk of aortic valve calcification (AVC) and AVC prevalence was increased with increasing number of MetS components (7). These findings suggest that MetS is a risk factor for AVC and raises the possibility that interventions targeting MetS might decrease AVC progression.
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Selected clinical issues in valve disease
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- 1 In this community study of patients with bicuspid aortic valve and no or minimal hemodynamic abnormality, long-term mortality is low but the incidence of cardiovascular events and AVR is high and is predicted by baseline valve degeneration point score (8).
- 2 The largest echocardiographic study to date in patients with systemic lupus erythematosus indicated that antiphospholipid antibodies are associated with mitral valve nodules and significant mitral regurgitation (MR) but not with aortic valve abnormalities, atherosclerosis, arterial stiffness, or left ventricular structure or function (9).
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Mitral regurgitation
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- 1 In patients with ruptured chordae and partially flail MV, most patients had a nonmyxomatous etiology that was associated with older age, degenerative changes such as mitral annular calcification and aortic sclerosis, and short-term symptoms (10).
- 2 In patients with ischemic mitral regurgitation (IMR), survival after coronary artery bypass graft surgery was influenced favorably by the presence of viable myocardium (11). By contrast, adding MV repair to coronary artery bypass graft did not affect survival except in patients without viable myocardium, in whom it increased early mortality.
- 3 The Euro Heart Survey (12) showed that significant differences exist between men and women with severe MR: 1) women were referred at a more advanced clinical state than men, although left ventricular function does not differ; 2) overall, the decision for surgery did not differ according to gender; however, a decision to operate was made less frequently in women with few or no symptoms; 3) in women, MV repair is less frequently performed and operative mortality tends to be higher than in men.
- 4 Angiotensin blockade by candesartan (n = 44) or ramipril (n = 47) at maximum tolerated dose was compared with placebo (n = 44) in a randomized trial with moderate or severe organic MR, and changes in regurgitant volume were determined. At one year, there were no significant changes in regurgitant volume (13).
- 5 Preoperative exercise duration was directly associated with outcome after MV surgery among patients with nonischemic MR; it predicted survival and symptom persistence better than commonly documented clinical variables (14). Thus, MV surgery is indicated not only in patients reporting symptoms but in those with markedly subnormal exercise duration even if symptoms are not reported.
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Infective endocarditis (IE)
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- 1 Clinically unapparent acute brain infarction, including large and multiple acute brain infarctions, seems to be common in patients with left-sided IE. Routine brain magnetic resonance imaging of all patients with left-sided IE may be indicated (15).
- 2 Echocardiography-guided risk stratification for surgery was shown to be a cost-attractive treatment strategy for IE; it improved outcome for an incremental cost of <$50,000/quality-adjusted life years (16). The echocardiography-guided strategy remains economically attractive across a broad range of assumptions.
- 3 Patients with type II diabetes mellitus had a significantly higher prevalence of IE independent of chronic and acute renal failure or valvular abnormalities (17). This result is consistent with the increased vulnerability of patients with diabetes mellitus to serious infections.
- 4 Among individuals with IE, a history of stroke and polymicrobial infection were significantly associated with risk for embolism (18).
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Percutaneous procedures
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- 1 The Percutaneous Septal Sinus Shortening (PS3 system) was effective in the amelioration of functional MR in an ovine model (19). The procedure uses standard catheter techniques and can be deployed largely under fluoroscopic guidance. In addition, the bridge element allows direct and precise septal-lateral mitral annular shortening to a diameter optimal for MR reduction.
- 2 Percutaneous edge-to-edge mitral valve repair with the Evalve MitraClip was accomplished successfully in patients with functional MR in the Endovascular Valve Edge-to-Edge Repair Study (EVEREST 1) trial. In this study, MR was reduced without major adverse events (20).
- 3 Pulmonary hypertension with an excessive transpulmonary gradient is not uncommon in patients with mitral stenosis; women seem to have a much greater risk of developing this problem (21). Despite higher right-sided pressures and worse symptoms, mitral valvuloplasty is equally successful and provided sustained benefit in this population of patients.
- 4 "Significant (3+ or 4+) aortic regurgitation is common after Cribier-Edwards prosthetic heart valve (PHV) implantation. It is noteworthy that aortic regurgitation >1+ was seen with a larger diameter PHV. Appropriate device sizing and advanced device designs may reduce the incidence and degree of aortic regurgitation after PHV implantation" (22).
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Surgery
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Valvular Regurgitation.
- 1 Survival after annuloplasty for IMR was adversely affected by global left ventricular dysfunction and postinfarct remodeling (23). Mitral regurgitation returns in a substantial proportion of patients, emphasizing the ventricular rather than valvar nature of this disease.
- 2 Surgical repair of IMR with the novel, asymmetric Carpentier-McCarthy-Adams IMR ET Logix Annuloplastic Ring provides "excellent early results" with effective reduction of anteroposterior dimension, leaflet tethering, and left ventricular volume (24). "This novel, etiology-specific strategy may result in improved outcomes in IMR patients, including lower incidence of recurrent MR."
- 3 Mitral valve repair is associated with lower long-term incidence of cardiovascular thromboemboli than mechanical PHV and with a smaller benefit compared with bioprosthetic PHV (25). However, there is a high rate of cardiovascular thromboemboli in all types of surgeries, including mitral valve repair, within the first postoperative month, and this extends to the first six months after surgery of MR and requires relatively prolonged anticoagulation for cardiovascular thromboemboli prevention in the first six postoperative months.
- 4 Tricuspid valve annuloplasty with the Edward MC3 ring was effective in the treatment of functional tricuspid regurgitation (26). This new surgical treatment may result in improved outcomes in patients with functional tricuspid regurgitation with the potential to preserve right ventricular function.
Prosthetic Heart Valve.
- 1 In a large observational study of Medicare beneficiaries that accounted for patient and hospital-level factors with follow-up extending to 13 years, patients receiving bioprosthetic valves had a modestly lower risk of death and lower rates of subsequent stroke, embolism, and hemorrhage, but a higher risk of repeat AVR. Given the low rate of repeat AVR, these data support broader use of bioprosthetic valves in older patients (27).
- 2 Inadequate anticoagulation was the predominant cause of prosthetic valve thrombosis. Successful thrombolysis was achieved at low risk of complications with intravenous thrombolytic therapy for both mitral and aortic valve thrombosis and in all types of prosthesis (28). Hence, we recommend thrombolytic therapy as a safe and effective nonsurgical method of treatment for prosthetic valve thrombosis.
- 3 In a randomized trial, rapid fibrinolytic therapy (large initial dose of streptokinase of 1.5 million U followed if required by 0.1 million U/h) was more efficacious in achieving a complete clinical response (p = 0.047) than the standard protocol (0.25 million U given 30 min followed by 0.1 million U/h) for treatment of a first episode of PHV thrombosis (29).
- 4 Severe valve prosthesis-patient mismatch, valve area
 0.65 cm2/m2, was a strong predictor of the worst long-term survival (47.4% at a mean follow-up of 6.7 years) among patients undergoing mechanical AVR (30). Valve prosthesis-patient mismatch was most likely to occur in small valve sizes and can be avoided at the time of surgery.
Hypertrophic Cardiomyopathy.
- 1 Intrinsic mitral valve pathology is commonly observed in hypertrophic cardiomyopathy patients with symptomatic obstruction undergoing myectomy. Echocardiography can identify MV features predictive of MV repair (31). The relative contribution of MV replacement and comorbidities on outcome needs further evaluation.
- 2 "Isolated septal myectomy is an extremely safe operation with little morbidity and no mortality and should be considered the first choice in the treatment of symptomatic patients with hypertropic obstructive cardiomyopathy" (32).
Other Surgery.
- 1 The Euro Heart Survey (33) showed: 1) surgery was denied in as many as one-half of patients with severe, symptomatic MR; 2) older age and comorbidity might be valid ground for deciding against surgery in certain cases; and 3) conversely, moderately decreased left ventricular ejection fraction, congestive heart failure, and moderate symptoms (New York Heart Association functional class II) should not lead to denial of surgery according to current guidelines.
- 2 Major patient risk factors for postoperative dialysis after coronary artery bypass graft were identified and were converted into a simple, accurate bedside risk tool that may facilitate improved assessment regarding risks of postoperative dialysis (34).
- 3 Population-based observational study quantified the long-term prognosis of patients with severe left ventricular dysfunction (grade 4 left ventricle) out to 10 years after surgical revascularization (35). Adjunctive therapies to revascularization may be needed.
- 4 The International Registry of Acute Aortic Dissection risk model predicts in-hospital mortality using a mathematical model and may be useful for considering risks and benefits of high-risk surgery (36).
- 5 Observant Jehovah’s Witnesses who underwent cardiac surgery without blood transfusion compared with non-Jehovah’s Witness patients returned to the operating room for bleeding more often but had a similar incidence of in-hospital and long-term death (37).
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References
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Comorbidities in severe aortic valve stenosisdo renal dysfunction, anemia or diabetes mellitus predict long-term outcome?. (abstr) J Am Coll Cardiol 2006;47(Suppl A):287A. 6. Koos R, Kuehl H, Manken A, et al. Association of low fetuin-A and inflammation with the severity of aortic valve calcification (AVC)(abstr) J Am Coll Cardiol 2006;47(Suppl A):287A. 7. Katz R, Wong N, Budoff M, et al. Features of the metabolic syndrome and diabetes mellitus as predictors of aortic valve calcifications as detected by electron beam computed tomography in the multi-ethnic study of atherosclerosis(abstr) J Am Coll Cardiol 2006;47(Suppl A):287A. 8. Michelena H, Nkomo V, Desjardins V, Tajik A, Enriquez-Sarano M. Long-term outcome of asymptomatic bicuspid aortic valve in the community(abstr) J Am Coll Cardiol 2006;47(Suppl A):276A. 9. Farzaneh-Far A, Roman M, Lockshin M, Devereux R, Paget S, Crow M. Impact of antiphospholipid antibodies on cardiovascular disease in systemic lupus erythematosus(abstr) J Am Coll Cardiol 2006;47(Suppl A):277A. 10. Adawi S, Aviram S, Lewis B, Shiran A. Is myxomatous mitral valve disease the leading cause of partially flail mitral valve leaflet and ruptured chordae?(abstr) J Am Coll Cardiol 2006;47(Suppl A):278A. 11. Polain de Waroux J, Pouleur AN, Benedicte B, et al. Survival after coronary revascularization, with and without mitral valve repair, in patients with ischemic mitral regurgitation. Importance of pre-operative myocardial viability(abstr) J Am Coll Cardiol 2006;47(Suppl A):278A. 12. Cachier A, Iung B, Messika-Zeitoun D, Tornos P, Himbert D, Butchart E. Clinical presentation and management of patients with severe mitral regurgitationare there differences between men and women?. (abstr) J Am Coll Cardiol 2006;47(Suppl A):279A. 13. Enriquez-Sarano M, Messika-Zeitoun D, Detain D, Avierinos J, Nkomo V, Tajik J. Effect of angiotensin blockade on the degree of organic mitral regurgitationa randomized clinical trial. (abstr) J Am Coll Cardiol 2006;47(Suppl A):279A. 14. Supino P, Borer J, Hocheiter C, Herrold E McM, Preibisz J, Kligfield P. Preoperative exercise capacity predicts survival and persistent symptoms after surgery for chronic nonischemic mitral regurgitation(abstr) J Am Coll Cardiol 2006;47(Suppl A):279A. 15. Thompson E, Goldstein S, Fuisz A, Mark A, Laureno R, Lin M. Prospective determination of the prevalence of clinically unapparent cerebral embolization in patients with left-sided infective endocarditis(abstr) J Am Coll Cardiol 2006;47(Suppl A):280A. 16. Liao L, Kong D, Samad Z, et al. Echocardiographic risk-stratification for early surgery in patients with endocarditis is a cost-attractive alternative to standard care(abstr) J Am Coll Cardiol 2006;47(Suppl A):280A. 17. Movahed M, Hashemzadeh M, Jamal M. Infectious endocarditis is independently associated with type II diabetes mellitus(abstr) J Am Coll Cardiol 2006;47(Suppl A):281A. 18. Anavekar NS, Anavekar NS, Tleyjeh I, et al. Baseline characteristics associated with embolism in infective endocarditis(abstr) J Am Coll Cardiol 2006;47(Suppl A):281A. 19. Rogers J, Macoviak J, Takeda P, Rahdert D, Low R. Percutaneous Septal Sinus Shortening (the PS3 System) ameliorates functional mitral regurgitation(abstr) J Am Coll Cardiol 2006;47(Suppl A):282A. 20. Block P, Hermann H, Whitlow P, et al. Percutaneous edge-to-edge mitral valve repair using the Evalve MitraClipinitial experience with functional mitral regurgitation in the EVEREST I trial. (abstr) J Am Coll Cardiol 2006;47(Suppl A):283A. 21. Krasuski R, Wang A, Kisslo K, Harrison K, Bashore T. Pulmonary hypertension with excessive transpulmonary gradients among mitral stenoticsprevalence and clinical outcome following percutaneous balloon mitral commissurotomy. (abstr) J Am Coll Cardiol 2006;47(Suppl A):283A. 22. Hanzel G, Abbas A, Dixon S, et al. The incidence of aortic regurgitation after percutaneous aortic valve implantation(abstr) J Am Coll Cardiol 2006;47(Suppl A):283A. 23. Dumont E, Gillinor AM, Blackston EH, Rajeswaran J, Colafranceshi S, Mihaljeric T. Functional ischemic mitral regurgitationimpact of left ventricular function on outcome. (abstr) J Am Coll Cardiol 2006;47(Suppl A):272A.[Free Full Text] 24. Daimon M, Fukuda S, Adams D, et al. Mitral valve repair with a novel etiology-specific annuloplasty ring for ischemic mitral regurgitationearly echocardiography results from a multi-center study. (abstr) J Am Coll Cardiol 2006;47(Suppl A):272A.[Free Full Text] 25. Russo A, Freeman M, Sundt T, Brown Jr R, Sarano M. Cerebrovascular thromboembolic events after mitral valve repairimplication for treatment of patients with mitral regurgitation. (abstr) J Am Coll Cardiol 2006;47(Suppl A):273A. 26. Fukuda S, Gillinov M, McCarthy P, et al. Initial experience of new three-dimensional annuloplasty ring for functional tricuspid regurgitation(abstr) J Am Coll Cardiol 2006;47(Suppl A):273A. 27. Schelbert E, Vaughan-Sarrazin M, Welke K, Rosenthal G. Valve type and long term outcomes after aortic valve replacement in older patients(abstr) J Am Coll Cardiol 2006;47(Suppl A):281A. 28. Omar Sr. AK. Thrombolytic therapy for left-sided prosthetic valve thrombosis(abstr) J Am Coll Cardiol 2006;47(Suppl A):285A. 29. Karthikevan G, Mathew N, Kalaivani M, Singh S, Math R, Shankar B. A prospective randomized trial of a rapid fibrinolytic protocol for left-sided prosthetic valve thrombosisinterim analysis. (abstr) J Am Coll Cardiol 2006;47(Suppl A):277A. 30. Mohan S, Kohsaka S, Contreras A, et al. Prosthesis-patient mismatch affects long-term survival after mechanical aortic valve replacement(abstr) J Am Coll Cardiol 2006;47(Suppl A):282A. 31. Kaple R, Murphy R, York A, et al. 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Mortality and morbidity...
Newer issues in valve...