1. Shariff N, Alluri K, Saba S. Failure rates of single- versus dual-coil nonrecalled sprint quattro defibrillator leads. Am J Cardiol 2015;115:202e205. 2. Kutyifa V, Huth Ruwald AC, Aktas MK, Jons C, McNitt S, Polonsky B, Geller L, Merkely B, Moss AJ, Zareba W, Bloch Thomsen PE. Clinical impact, safety, and efficacy of single- versus dualcoil ICD leads in MADIT-CRT. J Cardiovasc Electrophysiol 2013;24:1246e1252. 3. Birnie DH, Parkash R, Exner DV, Essebag V, Healey JS, Verma A, Coutu B, Kus T, Mangat I, Ayala-Paredes F, Nery P, Wells G, Krahn AD. Clinical predictors of Fidelis lead failure: report from the Canadian Heart Rhythm Society Device Committee. Circulation 2012;125:1217e1225. 4. Hauser RG, Maisel WH, Friedman PA, Kallinen LM, Mugglin AS, Kumar K, Hodge DO, Morrison TB, Hayes DL. Longevity of Sprint Fidelis implantable cardioverter-defibrillator leads and risk factors for failure: implications for patient management. Circulation 2011;123:358e363. 5. Eckstein J, Koller MT, Zabel M, Kalusche D, Schaer BA, Osswald S, Sticherling C. Necessity for surgical revision of defibrillator leads implanted long-term: causes and management. Circulation 2008;117:2727e2733. 6. Bernstein NE, Karam ET, Aizer A, Wong BC, Holmes DS, Bernstein SA, Chinitz LA. Rightsided implantation and subpectoral position are predisposing factors for fracture of a 6.6 French ICD lead. Pacing Clin Electrophysiol 2012;35:659e664. 7. Valk SD, Theuns DA, Jordaens L. Long-term performance of the St Jude Riata 1580e1582 ICD lead family. Neth Heart J 2013;21:127e134. 8. Epstein LM, Love CJ, Wilkoff BL, Chung MK, Hackler JW, Bongiorni MG, Segreti L, Carrillo RG, Baltodano P, Fischer A, Kennergren C, Viklund R, Mittal S, Arshad A, Ellenbogen KA, John RM, Maytin M. Superior vena cava defibrillator coils make transvenous lead extraction more challenging and riskier. J Am Coll Cardiol 2013;61:987e989. 9. Brunner MP, Cronin EM, Duarte VE, Yu C, Tarakji KG, Martin DO, Callahan T, Cantillon DJ, Niebauer MJ, Saliba WI, Kanj M, Wazni O, Baranowski B, Wilkoff BL. Clinical predictors of adverse patient outcomes in an experience of more than 5000 chronic endovascular pacemaker and defibrillator lead extractions. Heart Rhythm 2014;11:799e805. 10. Lickfett L, Bitzen A, Arepally A, Nasir K, Wolpert C, Jeong KM, Krause U, Schimpf R, Lewalter T, Calkins H, Jung W, Lüderitz B. Incidence of venous obstruction following insertion of an implantable cardioverter defibrillator. A study of systematic contrast venography on patients presenting for their first elective ICD generator replacement. Europace 2004;6:25e31. 11. Rinaldi CA, Simon RD, Geelen P, Reek S, Baszko A, Kuehl M, Gill JS. A randomized prospective study of single coil versus dual coil defibrillation in patients with ventricular arrhythmias undergoing implantable cardioverter defibrillator therapy. Pacing Clin Electrophysiol 2003;26:1684e1690. 12. Aoukar PS, Poole JE, Johnson GW, Anderson J, Hellkamp AS, Mark DB, Lee KL, Bardy GH. No benefit of a dual coil over a single coil ICD lead: evidence from the Sudden Cardiac Death in Heart Failure Trial. Heart Rhythm 2013;10:970e976. http://dx.doi.org/10.1016/j.amjcard.2015.04.037
Readers’ Comments
491
The Necessity of Comprehensive Searching and Quality Assessment in Meta-analyses
of heterogeneity and excessive influence from a single study, unfortunately, the review’s blatant methodologic weaknesses prevent it from being an effective tool for assisting clinical decision making. I hope that for future analyses, the investigators consider these points and the reporting protocols found in the Metaanalysis of Observational Studies in Epidemiology and other valuable guidance statements to improve the quality of their work.
After reading the meta-analysis on whole-grain intake and coronary heart disease (CHD) risk by Tang et al1 in the March 2015 issue of the American Journal of Cardiology, I considered the need to provide some constructive feedback. Systematic reviews and meta-analyses are regarded as being crucial to evidencebased practice, and information on protective factors for CHD is highly relevant, given that CHD is the leading cause of death in the United States.2 However, because of several major flaws in its execution, I have serious reservations about the findings of this review. First, the investigators failed to synthesize all available research on the topic into their review. For example, they only used 2 electronic search databases, when additional studies could have been identified through other sources such as the Cochrane Library or EMBASE. Also, the authors only included observational studies (namely prospective cohort and case-control) into the review, providing no explanation as to why they did not include more rigorous designs such as randomized controlled trials. When I performed a search using the authors’ search string on PubMed, one of the databases they used, I managed to find at least 4 trials that may have been eligible for inclusion into this review (citations available on request). Second, the authors did not seem have assessed the scientific quality of the included studies, negatively affecting the transparency of the review process. Thus, readers cannot properly assess its quality as a comprehensive review of the literature or assess the internal validity of the meta-analysis. Given that a number of reporting guidelines for reviews have been produced, these issues are almost inexcusable. In fact, when I applied the checklist for Meta-analysis of Observational Studies in Epidemiology,3 I found that 13 of the list’s 33 elements were not reported adequately in this article (checklist available on request). Despite being considered some of the strongest forms of medical evidence, like any other type of study, meta-analyses greatly vary in quality. Although the investigators successfully addressed issues
Michael Delgado, BA Miami, Florida 17 March 2015
1. Tang G, Wang D, Long J, Yang F, Si L. Meta-analysis of the association between whole grain intake and coronary heart disease. Am J Cardiol 2015;115:625e629. 2. Heart disease factors. Centers for Disease Control and Prevention. Available at: http:// www.cdc.gov/heartdisease/facts.htm. Updated February 19, 2015. Accessed on March 13, 2015. 3. Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, Moher D, Becker BJ, Sipe TA, Thacker SB. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA 2000;283:2008e2012. http://dx.doi.org/10.1016/j.amjcard.2015.04.038
Coronary Embolization in Hypertrophic Cardiomyopathy With Left Ventricular Apical Aneurysm. Does Follow-Up With Cardiac Magnetic Resonance Have a Role? We read the case by Kalra et al1 illustrating an example of coronary embolism originated into an apical aneurysm in a patient with hypertrophic cardiomyopathy (HC). These apical aneurysms are usually seen in severe midapical forms of the disease that can cause dynamic obstruction at the midventricular level and, occasionally, the development of a noncontractile apical aneurysm, which portends increased arrhythmic and cardioembolic risk. Because of the potential source of thrombus that they convey, the investigators emphasize the need for consideration of long-term oral anticoagulation in these patients, although administrated not indiscriminately to all of them, but on the basis of a “case-bycase” basis. As the investigators pointed out, in the largest published review on patients with HC, apical aneurysms were present only in about 2% of them,
492
The American Journal of Cardiology (www.ajconline.org)
but the rate of both cardiac embolism and apical thrombus within the aneurysm was high, as it happened in 4 of 28 patients (14%) with apical aneurysm.2 Thus, these specific forms of HC have potentially a significant risk of thrombus formation. However, controversies exist on whether these patients should be routinely treated with longterm oral anticoagulation. As a consequence, we are concerned about the optimal management of the anticoagulation on this specific group of patients because the consequences of a cardiac embolic event are often devastating. The 2011 American College of Cardiology Foundation/American Heart Association guidelines on HC3 recognize the superior ability of magnetic resonance over echocardiography in the detection of apical aneurysms and highlight that anticoagulation could be considered on the basis of the morphologic appearance of the aneurysm, supposedly in those with a transverse dimension of at least 3 cm, based on the mentioned reference. However, as Kalra et al explain in their report, the size of the apical aneurysm is not always related to the thrombus formation, and thus, caution should be exercised regarding to the recommendation of these guidelines. The recently published 2014 European Society of Cardiology guidelines on HC4 recommend the longterm anticoagulation only if a thrombus is detected within the apical aneurysm. At this point, it seems crucial the early detection of the apical thrombus. For this purpose, the best imaging technique nowadays is the cardiac magnetic resonance, which is able to detect both the transmural enhancement of the thinned apical wall and the thrombus that will warrant the start of long-term oral anticoagulation. The questions we would like to share are, first, whether patients with HC and apical aneurysm should be evaluated routinely by cardiac magnetic resonance instead of the widely available but less powerful echocardiography, to properly rule out the apical thrombus, and second, if these patients should be screened periodically for the detection of apical thrombus, that is at which interval the cardiac magnetic resonance should be repeated. Giving that the investigators of the report are authorized experts in the field, working in representative institutions with a huge experience in HC, we are sure
that their opinion would be of interest for the medical community. We would like to know if in the mentioned “case-by-case” basis for the indication for anticoagulation, the periodical use of cardiac magnetic resonance could play a role, to allow the early detection of the potentially harmful apical thrombus. Eduard Claver, MD Joel Salazar-Mendiguchía, MD Angel Cequier, MD, PhD Barcelona, Spain 26 April 2015
1. Kalra A, Maron MS, Rowin EJ, Colgan TK, Lesser JR, Maron BJ. Coronary embolization in hypertrophic cardiomyopathy with left ventricular apical aneurysm. Am J Cardiol 2015;115:1318e1319. 2. Maron MS, Finley JJ, Bos JM, Hauser TH, Manning WJ, Haas TS, Lesser JR, Udelson JE, Ackerman MJ, Maron BJ. Prevalence, clinical significance, and natural history of left ventricular apical aneurysms in hypertrophic cardiomyopathy. Circulation 2008;118: 1541e1549. 3. Gersh BJ, Maron BJ, Bonow RO, Dearani JA, Fifer MA, Link MS, Naidu SS, Nishimura RA, Ommen SR, Rakowski H, Seidman CE, Towbin JA, Udelson JE, Yancy CW. 2011 ACCF/AHA guideline 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. Developed in collaboration with the 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, and Society of Thoracic Surgeons. J Am Coll Cardiol 2011;58:e212ee260. 4. Elliott PM, Anastasakis A, Borger MA, Borggrefe M, Cecchi F, Charron P, Hagege AA, Lafont A, Limongelli G, Mahrholdt H, McKenna WJ, Mogensen J, Nihoyannopoulos P, Nistri S, Pieper PG, Pieske B, Rapezzi C, Rutten FH, Tillmanns C, Watkins H. 2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: the Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC). Eur Heart J 2014;35:2733e2779. http://dx.doi.org/10.1016/j.amjcard.2015.05.002
Reply Hypertrophic cardiomyopathy (HC) with left ventricular (LV) apical aneurysm is a relatively new subgroup of patients within the broad disease spectrum, best identified and defined by contrast cardiovascular magnetic resonance (CMR).1e4 We agree with and appreciate Drs. Claver, Salazar-Mendiguchia, and
Cequier’s observations and concerns regarding embolization in HC and LV apical aneurysm. The clinical question raised here concerns the frequency and nature of clot formation in the LV apex of these patients and the unpredictability of clinical events. Identification of thrombi situated in the aneurysm in this patient subset is not uncommon (i.e., 20%), and 5% of patients may experience an embolic event. As suggested by our report,1 clot size may be variable and include small thrombi (not always reliably identified by echocardiography) that are nevertheless capable of embolizing. It is apparent that CMR is the most effective imaging test to identify apical thrombi independent of size, and it is our practice to routinely use CMR for surveillance in this patient subgroup.1 However, a limitation to this strategy is that many patients with apical aneurysm will receive primary prevention implantable cardioverter-defibrillators and consequently are no longer eligible for CMR studies. In this circumstance, we may interrogate the apex of the LV using oblique (off-axis) echocardiographic imaging planes, often with the use of contrast, to improve the detection of thrombus over standard echocardiography.4 If clinical concern for thrombus formation remains, we may selectively evaluate patients with computed tomographic angiography. Certainly, any patient with HC with a visible apical thrombus deserves strong consideration for anticoagulation. Whether anticoagulant drugs should be routine in patients with HC and apical aneurysm is an open question, requiring more data for resolution, and therefore presently, those decisions can only be made on a case-by-case basis. Barry J. Maron, MD Minneapolis, Minnesota Ethan J. Rowin, MD Boston, Massachusetts Ankur Kalra, MD Minneapolis, Minnesota John R. Lesser, MD Minneapolis, Minnesota Martin S. Maron, MD Boston, Massachusetts 14 May 2015
1. Kalra A, Maron MS, Rowin EJ, Colgan TK, Lesser JR, Maron BJ. Coronary embolization in hypertrophic cardiomyopathy with left
Readers’ Comments
491
The Necessity of Comprehensive Searching and Quality Assessment in Meta-analyses
of heterogeneity and excessive influence from a single study, unfortunately, the review’s blatant methodologic weaknesses prevent it from being an effective tool for assisting clinical decision making. I hope that for future analyses, the investigators consider these points and the reporting protocols found in the Metaanalysis of Observational Studies in Epidemiology and other valuable guidance statements to improve the quality of their work.
After reading the meta-analysis on whole-grain intake and coronary heart disease (CHD) risk by Tang et al1 in the March 2015 issue of the American Journal of Cardiology, I considered the need to provide some constructive feedback. Systematic reviews and meta-analyses are regarded as being crucial to evidencebased practice, and information on protective factors for CHD is highly relevant, given that CHD is the leading cause of death in the United States.2 However, because of several major flaws in its execution, I have serious reservations about the findings of this review. First, the investigators failed to synthesize all available research on the topic into their review. For example, they only used 2 electronic search databases, when additional studies could have been identified through other sources such as the Cochrane Library or EMBASE. Also, the authors only included observational studies (namely prospective cohort and case-control) into the review, providing no explanation as to why they did not include more rigorous designs such as randomized controlled trials. When I performed a search using the authors’ search string on PubMed, one of the databases they used, I managed to find at least 4 trials that may have been eligible for inclusion into this review (citations available on request). Second, the authors did not seem have assessed the scientific quality of the included studies, negatively affecting the transparency of the review process. Thus, readers cannot properly assess its quality as a comprehensive review of the literature or assess the internal validity of the meta-analysis. Given that a number of reporting guidelines for reviews have been produced, these issues are almost inexcusable. In fact, when I applied the checklist for Meta-analysis of Observational Studies in Epidemiology,3 I found that 13 of the list’s 33 elements were not reported adequately in this article (checklist available on request). Despite being considered some of the strongest forms of medical evidence, like any other type of study, meta-analyses greatly vary in quality. Although the investigators successfully addressed issues
Michael Delgado, BA Miami, Florida 17 March 2015
1. Tang G, Wang D, Long J, Yang F, Si L. Meta-analysis of the association between whole grain intake and coronary heart disease. Am J Cardiol 2015;115:625e629. 2. Heart disease factors. Centers for Disease Control and Prevention. Available at: http:// www.cdc.gov/heartdisease/facts.htm. Updated February 19, 2015. Accessed on March 13, 2015. 3. Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, Moher D, Becker BJ, Sipe TA, Thacker SB. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA 2000;283:2008e2012. http://dx.doi.org/10.1016/j.amjcard.2015.04.038
Coronary Embolization in Hypertrophic Cardiomyopathy With Left Ventricular Apical Aneurysm. Does Follow-Up With Cardiac Magnetic Resonance Have a Role? We read the case by Kalra et al1 illustrating an example of coronary embolism originated into an apical aneurysm in a patient with hypertrophic cardiomyopathy (HC). These apical aneurysms are usually seen in severe midapical forms of the disease that can cause dynamic obstruction at the midventricular level and, occasionally, the development of a noncontractile apical aneurysm, which portends increased arrhythmic and cardioembolic risk. Because of the potential source of thrombus that they convey, the investigators emphasize the need for consideration of long-term oral anticoagulation in these patients, although administrated not indiscriminately to all of them, but on the basis of a “case-bycase” basis. As the investigators pointed out, in the largest published review on patients with HC, apical aneurysms were present only in about 2% of them,
492
The American Journal of Cardiology (www.ajconline.org)
but the rate of both cardiac embolism and apical thrombus within the aneurysm was high, as it happened in 4 of 28 patients (14%) with apical aneurysm.2 Thus, these specific forms of HC have potentially a significant risk of thrombus formation. However, controversies exist on whether these patients should be routinely treated with longterm oral anticoagulation. As a consequence, we are concerned about the optimal management of the anticoagulation on this specific group of patients because the consequences of a cardiac embolic event are often devastating. The 2011 American College of Cardiology Foundation/American Heart Association guidelines on HC3 recognize the superior ability of magnetic resonance over echocardiography in the detection of apical aneurysms and highlight that anticoagulation could be considered on the basis of the morphologic appearance of the aneurysm, supposedly in those with a transverse dimension of at least 3 cm, based on the mentioned reference. However, as Kalra et al explain in their report, the size of the apical aneurysm is not always related to the thrombus formation, and thus, caution should be exercised regarding to the recommendation of these guidelines. The recently published 2014 European Society of Cardiology guidelines on HC4 recommend the longterm anticoagulation only if a thrombus is detected within the apical aneurysm. At this point, it seems crucial the early detection of the apical thrombus. For this purpose, the best imaging technique nowadays is the cardiac magnetic resonance, which is able to detect both the transmural enhancement of the thinned apical wall and the thrombus that will warrant the start of long-term oral anticoagulation. The questions we would like to share are, first, whether patients with HC and apical aneurysm should be evaluated routinely by cardiac magnetic resonance instead of the widely available but less powerful echocardiography, to properly rule out the apical thrombus, and second, if these patients should be screened periodically for the detection of apical thrombus, that is at which interval the cardiac magnetic resonance should be repeated. Giving that the investigators of the report are authorized experts in the field, working in representative institutions with a huge experience in HC, we are sure
that their opinion would be of interest for the medical community. We would like to know if in the mentioned “case-by-case” basis for the indication for anticoagulation, the periodical use of cardiac magnetic resonance could play a role, to allow the early detection of the potentially harmful apical thrombus. Eduard Claver, MD Joel Salazar-Mendiguchía, MD Angel Cequier, MD, PhD Barcelona, Spain 26 April 2015
1. Kalra A, Maron MS, Rowin EJ, Colgan TK, Lesser JR, Maron BJ. Coronary embolization in hypertrophic cardiomyopathy with left ventricular apical aneurysm. Am J Cardiol 2015;115:1318e1319. 2. Maron MS, Finley JJ, Bos JM, Hauser TH, Manning WJ, Haas TS, Lesser JR, Udelson JE, Ackerman MJ, Maron BJ. Prevalence, clinical significance, and natural history of left ventricular apical aneurysms in hypertrophic cardiomyopathy. Circulation 2008;118: 1541e1549. 3. Gersh BJ, Maron BJ, Bonow RO, Dearani JA, Fifer MA, Link MS, Naidu SS, Nishimura RA, Ommen SR, Rakowski H, Seidman CE, Towbin JA, Udelson JE, Yancy CW. 2011 ACCF/AHA guideline 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. Developed in collaboration with the 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, and Society of Thoracic Surgeons. J Am Coll Cardiol 2011;58:e212ee260. 4. Elliott PM, Anastasakis A, Borger MA, Borggrefe M, Cecchi F, Charron P, Hagege AA, Lafont A, Limongelli G, Mahrholdt H, McKenna WJ, Mogensen J, Nihoyannopoulos P, Nistri S, Pieper PG, Pieske B, Rapezzi C, Rutten FH, Tillmanns C, Watkins H. 2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: the Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC). Eur Heart J 2014;35:2733e2779. http://dx.doi.org/10.1016/j.amjcard.2015.05.002
Reply Hypertrophic cardiomyopathy (HC) with left ventricular (LV) apical aneurysm is a relatively new subgroup of patients within the broad disease spectrum, best identified and defined by contrast cardiovascular magnetic resonance (CMR).1e4 We agree with and appreciate Drs. Claver, Salazar-Mendiguchia, and
Cequier’s observations and concerns regarding embolization in HC and LV apical aneurysm. The clinical question raised here concerns the frequency and nature of clot formation in the LV apex of these patients and the unpredictability of clinical events. Identification of thrombi situated in the aneurysm in this patient subset is not uncommon (i.e., 20%), and 5% of patients may experience an embolic event. As suggested by our report,1 clot size may be variable and include small thrombi (not always reliably identified by echocardiography) that are nevertheless capable of embolizing. It is apparent that CMR is the most effective imaging test to identify apical thrombi independent of size, and it is our practice to routinely use CMR for surveillance in this patient subgroup.1 However, a limitation to this strategy is that many patients with apical aneurysm will receive primary prevention implantable cardioverter-defibrillators and consequently are no longer eligible for CMR studies. In this circumstance, we may interrogate the apex of the LV using oblique (off-axis) echocardiographic imaging planes, often with the use of contrast, to improve the detection of thrombus over standard echocardiography.4 If clinical concern for thrombus formation remains, we may selectively evaluate patients with computed tomographic angiography. Certainly, any patient with HC with a visible apical thrombus deserves strong consideration for anticoagulation. Whether anticoagulant drugs should be routine in patients with HC and apical aneurysm is an open question, requiring more data for resolution, and therefore presently, those decisions can only be made on a case-by-case basis. Barry J. Maron, MD Minneapolis, Minnesota Ethan J. Rowin, MD Boston, Massachusetts Ankur Kalra, MD Minneapolis, Minnesota John R. Lesser, MD Minneapolis, Minnesota Martin S. Maron, MD Boston, Massachusetts 14 May 2015
1. Kalra A, Maron MS, Rowin EJ, Colgan TK, Lesser JR, Maron BJ. Coronary embolization in hypertrophic cardiomyopathy with left
