Obstruction in Hypertrophic Cardiomyopathy
2012; Lippincott Williams & Wilkins; Volume: 126; Issue: 20 Linguagem: Inglês
10.1161/circulationaha.112.144667
ISSN1524-4539
Autores Tópico(s)Cardiovascular Effects of Exercise
ResumoHomeCirculationVol. 126, No. 20Obstruction in Hypertrophic Cardiomyopathy Free AccessEditorialPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessEditorialPDF/EPUBObstruction in Hypertrophic CardiomyopathyHow Often Does It Occur? Should It be Treated? If So, How? Eugene Braunwald, MD Eugene BraunwaldEugene Braunwald From the TIMI Study Group, Division of Cardiovascular Medicine, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA. Originally published17 Oct 2012https://doi.org/10.1161/CIRCULATIONAHA.112.144667Circulation. 2012;126:2369–2370Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 1, 2012: Previous Version 1 Hypertrophic cardiomyopathy (HCM) is the most common monogenic cardiac disorder and has been estimated to occur in 1 of every 500 people in the general population, amounting to a total of ≈600 000 persons in the United States.1 Its pathophysiology and optimal management have been the subject of conjecture and debate for more than a century. The issues surrounding left ventricular outflow tract (LVOT) obstruction in HCM have evoked the most discussion.Article see p 2374In 1907, a German pathologist, A. Schminke, described 2 hearts from women in their mid-50s. Decades before the development of left heart catheterization, and before any pressure gradients had ever been measured in humans, he wrote the following: "Diffuse muscular hypertrophy of the left ventricular outflow tract causes an obstruction. The left ventricle has to work harder to overcome the obstruction. So, the primary hypertrophy will be accompanied by a secondary hypertrophy, causing an incremental (further) narrowing of the outflow tract."2 Thus, Schminke presciently understood the vicious circle of left hypertrophy → obstruction → more hypertrophy, etc. A half century later, Morrow and I, despite having access to left heart catheterization (but not being aware of Schmincke's insight), struggled to explain our findings in 2 patients who had subaortic pressure gradients but no evidence of obstruction in the potassium citrate–arrested heart, a condition which we initially (and awkwardly) termed functional aortic stenosis.3 However, we did conclude "that the obstruction can only be explained by muscular hypertrophy of the left ventricular outflow tract."3As open-heart surgery exploded in the early 1960s, patients with this condition (the name HCM had not yet been agreed on) were encountered with increasing frequency by cardiologists and cardiac surgeons around the world; the British surgeon, Sir Russell Brock provided especially useful insights.4 Indeed, HCM soon became the poster child for the hemodynamic era. Although, by definition, all patients had left ventricular hypertrophy, LVOT obstruction was variable; in some it was always present5; in a second group, LVOT obstruction occurred only on provocation6; and a third group had forms of left ventricular hypertrophy similar to those in the first 2 groups, but did they not exhibit LVOT obstruction even with provocation.5Because LVOT obstruction could be provoked or intensified by β adrenergic stimulation,6 it was logical to try to prevent it with β adrenergic blockers, which had just been developed and which proved helpful to many patients with HCM, perhaps less so to patients with severe LVOT obstruction in the basal state.7 Morrow at the National Institutes of Health8 and Kirklin and Ellis at the Mayo Clinic9 turned their attention to the development of a corrective operation, surgical septal myectomy (SSM). However, in those early years, the operation was found to be technically challenging, the risk was substantial, and it was carried out in only a small number of centers. Some observers even doubted that obstruction ever occurred in HCM and that the pressure differences between the left ventricle and the aorta, on which we based our recommendations about surgery, were artifacts.10,11Now, to fast-forward to 2006, when the Marons and their colleagues12 showed by echocardiography that LVOT gradients at rest or during exercise occur in 70% of patients with HCM, are frequently associated with symptoms and adverse clinical outcomes,13 and concluded that when these obstructions are not responsive to pharmacological therapy, they require mechanical relief. Two approaches to accomplish this are available today; the first is SSM, sometimes referred to as the Morrow procedure, which has gradually become both more extensive and safer over the years. In 1995, alcohol septal ablation (ASA) was introduced,14 and because it relieved obstruction without requiring open-heart surgery, it quickly became the more frequently used procedure. However, SSM has continued to be carried out, mostly at specialized centers, and it is still considered to be the gold standard.15 The question most frequently asked today is which of these procedures is preferable and for whom?Three major comparisons are available. Argawal et al16 performed a comparison of the results in 8 institutions in which both procedures were used; 326 patients received SSM and 380 ASA. Leonardi et al17 compared the results on 1887 patients who received SSM with those on 2153 patients who received ASA, usually in different hospitals. Several studies found their way into both comparisons. Both analyses concluded that the mortality rates were similarly low with both procedures. However, Agarwal et al16 pointed out that ASA increased the need for implantation of a permanent pacemaker and left patients with low, but significantly higher, LVOT pressure gradients than did SSM.In this issue of Circulation, the excellent study by Sorajja et al18 from the Mayo Clinic, Rochester provides the largest single-center comparison of 177 patients who underwent ASA with an equal number of age- and sex-matched patients who underwent SSM. These 2 groups were not randomized, and the time that these procedures were carried out differed, from 1998 to 2010 for ASA and from 1983 to 2001 for SSM. At baseline, when compared with the SSM patients, the ASA patients had a significantly greater incidence of New York Heart Association class III/IV, and more frequently had a history of coronary artery disease and of treatment with a β-blocker. Quite remarkably, the 8-year survival estimates were identical, at 79% in both groups. However, the ASA patients had a residual gradient averaging 11 mm Hg and early pacemaker dependency in 20% of patients, compared with 5 mm Hg and 2%, respectively for SSM patients. During prolonged follow-up of ASA patients, 5.6% required subsequent SSM and 2.8% repeat SA. The postablation LVOT gradient in ASA patients was an independent predictor of both all-cause mortality and subsequent need for these reinterventions.The American College of Cardiology/American Heart Association Guidelines for the Treatment of HCM published in 2011 recommended, with a Class I indication, that "septal reduction therapy should be performed only by experienced operators … and only for the treatment of patients with severe drug-refractory symptoms and LVOT obstruction." They also provided a IIa recommendation that SSM "is the first consideration for the majority of eligible patients with HCM" and that "when surgery is contraindicated, or the risk is considered unacceptable because of serious comorbidity or advanced age, ASA … can be beneficial in … patients with HCM with LVOT obstruction and severe drug-refractory symptoms."19 The study by Sorajja et al18 provides further support for these recommendations.Ordinarily, when there is a question regarding the choice between 2 competing therapeutic approaches, a randomized clinical trial is used to provide the answer. However, Olivotto et al20 have made the case, and I believe quite convincingly, that such a trial presents logistical hurdles that cannot be surmounted in the foreseeable future.So, where do go from here? The available comparisons between the 2 approaches to septal reduction therapy are largely retrospective, and the risks for bias, both in patient selection and publication, creep in. A prospective multicenter registry that provides detailed baseline characteristics and descriptions of the procedure, as well as careful and systematic follow-up, could be very helpful. Much of the early work on HCM was conducted at the National Heart, Lung, and Blood Institute, which has had extensive favorable experience with prospective registries—on cardiac transplantation, pulmonary hypertension, and assisted circulation, to name a few. It would now be quite appropriate for the institute to organize a comparison of these 2 techniques of septal reduction, which would be relatively inexpensive and cost-effective at a time of fiscal stringency.DisclosuresNone.FootnotesThe opinions expressed in this article are not necessarily those of the editors or of the American Heart Association.Correspondence to Eugene Braunwald, MD, TIMI Study Group, 350 Longwood Avenue, Boston, MA 02115. E-mail [email protected]orgReferences1. Maron BJ, Maron MS. Hypertrophic cardiomyopathy.Lancet.2012; Aug3. [Epub ahead of print].MedlineGoogle Scholar2. Schmincke A. Ueber linkseitige muskulose conustenosen. Deutsche Med Wochenschr. 1907; 33:2082–2085.CrossrefGoogle Scholar3. Morrow AG, Braunwald E. Functional aortic stenosis: a malformation characterized by resistance to left ventricular outflow without anatomic obstruction. Circulation. 1959; 20:181–189.LinkGoogle Scholar4. Brock R. Functional obstruction of the left ventricle (acquired aortic subvalvar stenosis). Guys Hosp Reports. 1959; 108:126–143.MedlineGoogle Scholar5. Braunwald E, Brockenbrough EC, Morrow AG. Hypertrophic subaortic stenosis – a broadened concept. [Editorial]. Circulation. 1962; 26:161–165.LinkGoogle Scholar6. Braunwald E, Ebert PA. Hemodynamic alterations in idiopathic subaortic stenosis induced by sympathomimetic drugs. Am J Cardiol. 1962; 10:489–495.CrossrefMedlineGoogle Scholar7. Harrison DC, Braunwald E, Glick G, Mason DT, Chidsey CA, Ross J. Effects of beta adrenergic blockade on the circulation with particular reference to observations in patients with hypertrophic subaortic stenosis.Circulation. 1964; 29:84–98.LinkGoogle Scholar8. Morrow AG, Brockenbrough EC. Surgical treatment of idiopathic hypertrophic subaortic stenosis. Ann Surg. 1961; 154:181–189.CrossrefMedlineGoogle Scholar9. Kirklin JW, Ellis FH. Surgical relief of diffuse subvalvular aortic stenosis. Circulation. 1961; 24:739–742.LinkGoogle Scholar10. Criley JM, Lewis KB, White RI, Ross RS. Pressure gradients without obstruction: a new concept of "hypertrophic subaortic stenosis."Circulation. 1964; 32:881–887.LinkGoogle Scholar11. Murgo JP. Does outflow obstruction exist in hypertrophic cardiomyopathy? N Engl J Med. 1982; 307:1008–1009.CrossrefMedlineGoogle Scholar12. Maron MS, Olivotto I, Zenovich AG, Link MS, Pandian NG, Kuvin JT, Nistri S, Cecchi F, Udelson JE, Maron BJ. Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction. Circulation. 2006; 114:2232–2239.LinkGoogle Scholar13. Maron MS, Olivotto I, Betocchi S, Casey SA, Lesser JR, Losi MA, Cecchi F, Maron BJ. Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy. N Engl J Med. 2003; 348:295–303.CrossrefMedlineGoogle Scholar14. Sigwart U. Non-surgical myocardial reduction for hypertrophic obstructive cardiomyopathy. Lancet. 1995; 346:211–214.CrossrefMedlineGoogle Scholar15. Maron BJ. Commentary and re-appraisal: Surgical septal myectomy vs. alcohol ablation: After a decade of controversy and mismatch between clinical practice and guidelines. Prog Cardiovasc Dis. 2012; 54:523–528.CrossrefMedlineGoogle Scholar16. Agarwal S, Tuzcu EM, Desai MY, Smedira N, Lever HM, Lytle BW, Kapadia SR. Updated meta-analysis of septal alcohol ablation versus myectomy for hypertrophic cardiomyopathy. J Am Coll Cardiol. 2010; 55:823–834.CrossrefMedlineGoogle Scholar17. Leonardi RA, Kransdorf EP, Simel DL, Wang A. Meta-analysis of septal reduction therapies for obstructive hypertrophic cardiomyopathy: comparative rates of overall mortality and sudden cardiac death after treatment. Circ Cardiovasc Interv. 2010; 3:97–104.LinkGoogle Scholar18. Sorajja P, Ommen SR, Holmes DR, Dearani JA, Rihal CS, Gersh BJ, Lennon RJ, Nishimura RA. Survival after alcohol septal ablation for obstructive hypertrophic cardiomyopathy. Circulation.2012; 126:2374–2380.LinkGoogle Scholar19. Gersh BJ, Maron BJ, Bonow RO, Derani JA, Fifer MA, Link MS, Naidu SS, Nishimura RA, Ommen SR, Rakowski H, Seidman CE, Towbin JA, Udelson JE, Yancy CW. American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines; American Association for Thoracic Surgery; American Society of Echocardiography; American society of Nuclear Cardiology; Heart Failure Society of America; Heart Rhythm Society; Society for Cardiovascular Angiography and Interventions; Society of Thoracic Surgeons.2011 ACC/AHA guidelines for the diagnosis and treatment of hypertrophic cardiomyopathy: a report of the American College of Cardiology Foundation; American Heart Association Task Force on Practice Guidelines.Circulation.2011; 124: e-783– e-831.Google Scholar20. Olivotto I, Ommen SR, Maron MS, Cecchi F, Maron BJ. Surgical myectomy versus alcohol septal ablation for obstructive hypertrophic cardiomyopathy: will there ever be a randomized trial? J Am Coll Cardiol. 2007; 50:831–834.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Ji Q, Wang Y, Yang Y, Xia L, Qi X and Wang C (2021) Septuagenarians with hypertrophic obstructive cardiomyopathy undergoing myectomy: the experience of a single center, Surgery Today, 10.1007/s00595-021-02272-y, 51:9, (1471-1479), Online publication date: 1-Sep-2021. Ji Q, Wang Y, Yang Y, Xia L, Ding W, Song K, Wang C and Sciarra L (2020) Characteristics and Surgical Results of Patients with Hypertrophic Obstructive Cardiomyopathy without Intrinsic Mitral Valve Diseases Undergoing Mitral Subvalvular Procedures during Myectomy, Cardiology Research and Practice, 10.1155/2020/8875405, 2020, (1-9), Online publication date: 9-Dec-2020. Cui H, Schaff H, Abel M, Helder M, Frye R, Ommen S and Nishimura R (2020) Left ventricular ejection hemodynamics before and after relief of outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy and valvular aortic stenosis, The Journal of Thoracic and Cardiovascular Surgery, 10.1016/j.jtcvs.2019.03.071, 159:3, (844-852.e1), Online publication date: 1-Mar-2020. Zhu C, Tang B, Cui H, Wang S, Xiao M, Chen Z, Meng Y, Zhao S, Song Y, Yu Q and Wang S (2019) Predictors of long‐term outcome after septal myectomy in symptomatic hypertrophic obstructive cardiomyopathy patients with previous alcohol septal ablation and residual obstruction, Journal of Cardiac Surgery, 10.1111/jocs.14072, 34:7, (533-540), Online publication date: 1-Jul-2019. Badran H, Alamin A, Ahmed N and Abdel Kareem T (2019) Left ventricular mechanics before and after myectomy in patients with hypertrophic obstructive cardiomyopathy, Menoufia Medical Journal, 10.4103/mmj.mmj_35_17, 32:3, (836), . Braunwald E (2019) Hypertrophic Cardiomyopathy: The Past, the Present, and the Future Hypertrophic Cardiomyopathy, 10.1007/978-3-319-92423-6_1, (1-8), . Varma P, Raman S, Neema P and Shekar P (2015) Hypertrophic cardiomyopathy, Indian Journal of Thoracic and Cardiovascular Surgery, 10.1007/s12055-015-0364-7, 31:2, (153-161), Online publication date: 1-Jun-2015. Braunwald E (2015) Hypertrophic Cardiomyopathy: The Past, the Present, and the Future Hypertrophic Cardiomyopathy, 10.1007/978-1-4471-4956-9_1, (1-8), . Gersh B and Nishimura R (2014) Tratamiento de la miocardiopatía hipertrófica sintomática: ¿pastillas, alcohol o bisturí?, Revista Española de Cardiología, 10.1016/j.recesp.2014.01.007, 67:5, (341-344), Online publication date: 1-May-2014. Gersh B and Nishimura R (2014) Management of Symptomatic Hypertrophic Cardiomyopathy: Pills, Alcohol, or the Scalpel?, Revista Española de Cardiología (English Edition), 10.1016/j.rec.2014.01.006, 67:5, (341-344), Online publication date: 1-May-2014. Varma P and Neema P (2014) Hypertrophic cardiomyopathy: Part 1 - Introduction, pathology and pathophysiology, Annals of Cardiac Anaesthesia, 10.4103/0971-9784.129841, 17:2, (118), . November 13, 2012Vol 126, Issue 20 Advertisement Article InformationMetrics © 2012 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.112.144667PMID: 23076969 Originally publishedOctober 17, 2012 Keywordsablation techniquesEditorialsPDF download Advertisement SubjectsCatheter Ablation and Implantable Cardioverter-Defibrillator
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