1130 Correspondence
REFERENCES 1. Jenni R, Oechslin E, Schneider J, Attenhofer Jost C, Kaufmann PA. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart 2001;86:666-71. 2. Wessels A, Sedmera D. Developmental anatomy of the heart: a tale of mice and man. Physiol Genomics 2003;15:165-76. 3. Paterick TE, Gerber TC, Pradhan SR, Lindor NM, Tajik AJ. Left ventricular noncompaction cardiomyopathy: what do we know? Rev Cardiovasc Med 2010;11:92-9. 4. Arbustini E, Narula N, Dec GW, Reddy KS, Greenberg B, Kushwaha S, et al. The MOGE(S) classification for a phenotype-genotype nomenclature of cardiomyopathy: endorsed by the World Heart Federation. J Am Coll Cardiol 2013;62:2046-72. 5. Chin TK, Perloff JK, Williams RG, Jue K, Mohrmann R. Isolated noncompaction of left ventricular myocardium. A study of eight cases. Circulation 1990;82:507-13. 6. St€ ollberger C, Finsterer J, Blazek G. Left ventricular hypertrabeculation/noncompaction and association with additional cardiac abnormalities and neuromuscular disorders. Am J Cardiol 2002;90: 899-902. 7. Paterick TE, Umland MM, Jan MF, Ammar KA, Kramer C, Khandheria BK, et al. Left ventricular noncompaction: a 25-year odyssey. J Am Soc Echocardiogr 2012;25:363-75. 8. Kohli SK, Pantazis AA, Shah JS, Adeyemi B, Jackson G, McKenna WJ, et al. Diagnosis of left-ventricular non-compaction in patients with leftventricular systolic dysfunction: time for a reappraisal of diagnostic criteria? Eur Heart J 2008;29:89-95. 9. St€ ollberger C, Finsterer J. Left ventricular hypertrabeculation/noncompaction. J Am Soc Echocardiogr 2004;17:91-100. 10. Stanton C, Bruce C, Connolly H, Brady P, Syed I, Hodge D, et al. Isolated left ventricular noncompaction syndrome. Am J Cardiol 2009;104: 1135-8. 11. Burke A, Mont E, Kutys R, Virmani R. Left ventricular noncompaction: a pathological study of 14 cases. Hum Pathol 2005;36:403-11. 12. Freedom RM, Yoo SJ, Perrin D, Taylor G, Petersen S, Anderson RH. The morphological spectrum of ventricular noncompaction. Cardiol Young 2005;15:345-64. 13. Kansal S, Roitman D, Sheffield LT. Interventricular septal thickness and left ventricular hypertrophy. An echocardiographic study. Circulation 1979; 60:1058-65. 14. Epstein SE, Henry WL, Clark CE, Roberts WC, Maron BJ, Ferrans VJ, et al. Asymmetric septal hypertrophy. Ann Intern Med 1974;81:650-80. 15. Williams LK, Frenneaux MP, Steeds RP. Echocardiography in hypertrophic cardiomyopathy diagnosis, prognosis, and role in management. Eur J Echocardiogr 2009;10:iii9-14. 16. Henry WL, Clark CE, Epstein SE. Asymmetric septal hypertrophy. Echocardiographic identification of the pathognomonic anatomic abnormality of IHSS. Circulation 1973;47:225-33. 17. Paterick TE, Tajik AJ. Left ventricular noncompaction. Circ J 2012;76: 1556-62. 18. St€ ollberger C, Gerecke B, Finsterer J, Engberding R. Refinement of echocardiographic criteria for left ventricular noncompaction. Int J Cardiol 2013;165:463-7. 19. Willemsen HM, van den Berg MP. A few more pieces in the puzzle of noncompaction cardiomyopathy. Eur J Heart Fail 2011;13:127-9. 20. Attenhofer Jost CH, Connolly HM. Left ventricular non-compaction: dreaming of the perfect diagnostic tool. Eur J Heart Fail 2012;14:113-4. 21. Peters F, Khandheria BK. Isolated left ventricular noncompaction: what do we really know? Curr Cardiol Rep 2012;14:381-8. 22. Habib G, Charron P, Eicher JC, Giorgi R, Donal E, Laperche T, et al. Isolated left ventricular non-compaction in adults: clinical and echocardiographic features in 105 patients. Results from a French registry. Eur J Heart Fail 2011;13:177-85.
Journal of the American Society of Echocardiography October 2014
23. Aras D, Tufekcioglu O, Ergun K, Ozeke O, Yildiz A, Topaloglu S, et al. Clinical features of isolated ventricular noncompaction in adults long-term clinical course, echocardiographic properties, and predictors of left ventricular failure. J Card Fail 2006;12:726-33. 24. Belanger AR, Miller MA, Donthireddi UR, Najovits AJ, Goldman ME. New classification scheme of left ventricular noncompaction and correlation with ventricular performance. Am J Cardiol 2008;102:92-6. 25. Fazio G, Novo G, Casalicchio C, Di Gesaro G, Sutera L, Grassedonio E, et al. Left ventricular non-compaction cardiomyopathy in children: is segmental fibrosis the cause of tissue Doppler alterations and of EF reduction? Int J Cardiol 2009;132:278-80. 26. Nucifora G, Aquaro GD, Pingitore A, Masci PG, Lombardi M. Myocardial fibrosis in isolated left ventricular non-compaction and its relation to disease severity. Eur J Heart Fail 2011;13:170-6. 27. Gebhard C, St€ahli BE, Greutmann M, Biaggi P, Jenni R, Tanner FC. Reduced left ventricular compacta thickness: a novel echocardiographic criterion for non-compaction cardiomyopathy. J Am Soc Echocardiogr 2012;25:1050-7. 28. Peters F, Khandheria BK, Libhaber E, Maharaj N, Dos Santos C, Matioda H, et al. Left ventricular twist in left ventricular noncompaction. Eur Heart J Cardiovasc Imaging 2014;15:48-55. 29. Captur G, Muthurangu V, Cook C, Flett AS, Wilson R, Barison A, et al. Quantification of left ventricular trabeculae using fractal analysis. J Cardiovasc Magn Reson 2013;15:36. 30. Thavendiranathan P, Dahiya A, Phelan D, Desai MY, Tang WH. Isolated left ventricular non-compaction controversies in diagnostic criteria, adverse outcomes and management. Heart 2013;99:681-9. http://dx.doi.org/10.1016/j.echo.2014.06.015
Beware of Life-Threatening Activation of Air Bubble Detector during Contrast Echocardiography in Patients on Venoarterial Extracorporeal Membrane Oxygenator Support To the Editor: Venoarterial extracorporeal membrane oxygenation (ECMO) is a temporizing therapy for patients with refractory cardiogenic shock, and it may also be a bridge to destination therapy or cardiac transplantation. Patients requiring venoarterial ECMO are, by definition, on the verge of cardiopulmonary collapse. Acute disruption of forward flow in ECMO-dependent patients will result in severe hypoperfusion and must be avoided at all costs.1 It is common practice to use contrast transthoracic echocardiography to improve the visualization of endocardial borders and allow more accurate assessments of ventricular function.2-4 This information is used clinically to determine whether to wean patients from ECMO support. The ECMO system used at our institution (CARDIOHELP; MAQUET Medical Systems USA, Wayne, NJ) has an integrated sensor that uses ultrasound to detect changes in flow dynamics associated with the presence of air bubbles or thrombi >5 mm in dimension. Activation of the bubble detector results in an alarm, followed by pump shutdown. If the alarm is not overridden within 6 sec, ‘‘zero-flow mode’’ is engaged. This mode applies sufficient revolutions per minute to prevent backflow from the arterial cannula into the venous cannula and prevents forward flow as well, hence the name zero-flow mode. This safety feature is designed to prevent deleterious cardiovascular and neurologic sequelae associated with air embolism during ECMO. Nevertheless, although this is a safety feature, stopping the ECMO circuitry and therefore the blood flow may be followed by deleterious consequences such as hypotension or the occurrence of thrombi.
Correspondence 1131
Journal of the American Society of Echocardiography Volume 27 Number 10
Although the administration of contrast agents has been deemed safe, we have had two instances at our institution in which the peripheral administration of a microbubble contrast agent, namely, Definity (perflutren lipid microsphere; Lantheus Medical Imaging, North Billerica, MA) during contrast transthoracic echocardiography resulted in activation of the ECMO bubble detector alarm and subsequent engagement of zero-flow mode, resulting in hemodynamic instability.5 Expedient restoration of flow is necessary to avoid grave hemodynamic consequences in patients who are already refractory to maximum inotropic and vasopressor therapy, as well as organ ischemia and circuit thrombosis. However, the need to restore forward flow must be balanced with the need to detect and prevent arterial embolization. We believe that the cause of the air bubble alarm in these cases was the administration of a contrast medium specifically designed to enhance ultrasonographic imaging, which magnified the signal perceived by the air bubble detector. It seems intuitive that the administration of echocardiographic contrast could create an ultrasonographic pattern consistent with turbulent flow that may be interpreted by the sensor as an embolus or a similar occurrence. In any case, it is detected as an event worthy of alarm that requires immediate clinical evaluation to prevent a shutdown for safety reasons. An unexpected alarm of this level of clinical significance should not be haphazardly silenced or overridden. Further investigation into the circumstances surrounding these incidents revealed several learning points that may be helpful in anticipating and avoiding similar events in the future. Safely proceeding with contrast echocardiography in an ECMO patient requires that the provider anticipate and plan for potential sensor alarms and their downstream consequences, including engaging a zero-flow state. We recommend that the circuit be inspected visually before contrast administration, to minimize the chance of a true embolic event being disregarded as an artifact. An experienced team should be present during the study and should include, if possible, the attending cardiothoracic surgeon, the intensivist, and the perfusionist in addition to the
echocardiography team. If possible, contrast transthoracic echocardiography in ECMO patients should be performed during regular working hours, when an abundance of resources and personnel are readily available to aptly handle such occurrences; other possible approaches are to completely avoid the use of contrast agents in ECMO patients and to temporarily disconnect the bubble alarm while a study is under way. In any event, further data are needed before a valid decision can be made on the best way to proceed in these circumstances.
Loreta Grecu, MD Michael A. Fishman, MD, MBA Yale University School of Medicine, Department of Anesthesiology New Haven, Connecticut REFERENCES 1. Allen S, Holena D, McCunn M, Kohl B, Sarani B. A review of the fundamental principles and evidence base in the use of extracorporeal membrane oxygenation (ECMO) in critically ill adult patients. J Intensive Care Med 2011;26:13-26. 2. Bhatia VK, Senior R. Contrast echocardiography: evidence for clinical use. J Am Soc Echocardiogr 2008;21:409-16. 3. Shah BN. Echocardiography in the era of multimodality cardiovascular imaging. Biomed Res Int 2013;2013:310483. 4. Wei K, Mulvagh SL, Carson L, Davidoff R, Gabriel R, Grimm RA, et al. The safety of Definity and Optison for ultrasound image enhancement: a retrospective analysis of 78,383 administered contrast doses. J Am Soc Echocardiogr 2008;21:1202-6. 5. Platts D, Fraser JF, Mullany D, Burstow D. Left ventricular endocardial definition enhancement using perflutren microsphere contrast echocardiography during peripheral venoarterial extracorporeal membranous oxygenation. Echocardiography 2010;27:E112-4. http://dx.doi.org/10.1016/j.echo.2014.06.010
REFERENCES 1. Jenni R, Oechslin E, Schneider J, Attenhofer Jost C, Kaufmann PA. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart 2001;86:666-71. 2. Wessels A, Sedmera D. Developmental anatomy of the heart: a tale of mice and man. Physiol Genomics 2003;15:165-76. 3. Paterick TE, Gerber TC, Pradhan SR, Lindor NM, Tajik AJ. Left ventricular noncompaction cardiomyopathy: what do we know? Rev Cardiovasc Med 2010;11:92-9. 4. Arbustini E, Narula N, Dec GW, Reddy KS, Greenberg B, Kushwaha S, et al. The MOGE(S) classification for a phenotype-genotype nomenclature of cardiomyopathy: endorsed by the World Heart Federation. J Am Coll Cardiol 2013;62:2046-72. 5. Chin TK, Perloff JK, Williams RG, Jue K, Mohrmann R. Isolated noncompaction of left ventricular myocardium. A study of eight cases. Circulation 1990;82:507-13. 6. St€ ollberger C, Finsterer J, Blazek G. Left ventricular hypertrabeculation/noncompaction and association with additional cardiac abnormalities and neuromuscular disorders. Am J Cardiol 2002;90: 899-902. 7. Paterick TE, Umland MM, Jan MF, Ammar KA, Kramer C, Khandheria BK, et al. Left ventricular noncompaction: a 25-year odyssey. J Am Soc Echocardiogr 2012;25:363-75. 8. Kohli SK, Pantazis AA, Shah JS, Adeyemi B, Jackson G, McKenna WJ, et al. Diagnosis of left-ventricular non-compaction in patients with leftventricular systolic dysfunction: time for a reappraisal of diagnostic criteria? Eur Heart J 2008;29:89-95. 9. St€ ollberger C, Finsterer J. Left ventricular hypertrabeculation/noncompaction. J Am Soc Echocardiogr 2004;17:91-100. 10. Stanton C, Bruce C, Connolly H, Brady P, Syed I, Hodge D, et al. Isolated left ventricular noncompaction syndrome. Am J Cardiol 2009;104: 1135-8. 11. Burke A, Mont E, Kutys R, Virmani R. Left ventricular noncompaction: a pathological study of 14 cases. Hum Pathol 2005;36:403-11. 12. Freedom RM, Yoo SJ, Perrin D, Taylor G, Petersen S, Anderson RH. The morphological spectrum of ventricular noncompaction. Cardiol Young 2005;15:345-64. 13. Kansal S, Roitman D, Sheffield LT. Interventricular septal thickness and left ventricular hypertrophy. An echocardiographic study. Circulation 1979; 60:1058-65. 14. Epstein SE, Henry WL, Clark CE, Roberts WC, Maron BJ, Ferrans VJ, et al. Asymmetric septal hypertrophy. Ann Intern Med 1974;81:650-80. 15. Williams LK, Frenneaux MP, Steeds RP. Echocardiography in hypertrophic cardiomyopathy diagnosis, prognosis, and role in management. Eur J Echocardiogr 2009;10:iii9-14. 16. Henry WL, Clark CE, Epstein SE. Asymmetric septal hypertrophy. Echocardiographic identification of the pathognomonic anatomic abnormality of IHSS. Circulation 1973;47:225-33. 17. Paterick TE, Tajik AJ. Left ventricular noncompaction. Circ J 2012;76: 1556-62. 18. St€ ollberger C, Gerecke B, Finsterer J, Engberding R. Refinement of echocardiographic criteria for left ventricular noncompaction. Int J Cardiol 2013;165:463-7. 19. Willemsen HM, van den Berg MP. A few more pieces in the puzzle of noncompaction cardiomyopathy. Eur J Heart Fail 2011;13:127-9. 20. Attenhofer Jost CH, Connolly HM. Left ventricular non-compaction: dreaming of the perfect diagnostic tool. Eur J Heart Fail 2012;14:113-4. 21. Peters F, Khandheria BK. Isolated left ventricular noncompaction: what do we really know? Curr Cardiol Rep 2012;14:381-8. 22. Habib G, Charron P, Eicher JC, Giorgi R, Donal E, Laperche T, et al. Isolated left ventricular non-compaction in adults: clinical and echocardiographic features in 105 patients. Results from a French registry. Eur J Heart Fail 2011;13:177-85.
Journal of the American Society of Echocardiography October 2014
23. Aras D, Tufekcioglu O, Ergun K, Ozeke O, Yildiz A, Topaloglu S, et al. Clinical features of isolated ventricular noncompaction in adults long-term clinical course, echocardiographic properties, and predictors of left ventricular failure. J Card Fail 2006;12:726-33. 24. Belanger AR, Miller MA, Donthireddi UR, Najovits AJ, Goldman ME. New classification scheme of left ventricular noncompaction and correlation with ventricular performance. Am J Cardiol 2008;102:92-6. 25. Fazio G, Novo G, Casalicchio C, Di Gesaro G, Sutera L, Grassedonio E, et al. Left ventricular non-compaction cardiomyopathy in children: is segmental fibrosis the cause of tissue Doppler alterations and of EF reduction? Int J Cardiol 2009;132:278-80. 26. Nucifora G, Aquaro GD, Pingitore A, Masci PG, Lombardi M. Myocardial fibrosis in isolated left ventricular non-compaction and its relation to disease severity. Eur J Heart Fail 2011;13:170-6. 27. Gebhard C, St€ahli BE, Greutmann M, Biaggi P, Jenni R, Tanner FC. Reduced left ventricular compacta thickness: a novel echocardiographic criterion for non-compaction cardiomyopathy. J Am Soc Echocardiogr 2012;25:1050-7. 28. Peters F, Khandheria BK, Libhaber E, Maharaj N, Dos Santos C, Matioda H, et al. Left ventricular twist in left ventricular noncompaction. Eur Heart J Cardiovasc Imaging 2014;15:48-55. 29. Captur G, Muthurangu V, Cook C, Flett AS, Wilson R, Barison A, et al. Quantification of left ventricular trabeculae using fractal analysis. J Cardiovasc Magn Reson 2013;15:36. 30. Thavendiranathan P, Dahiya A, Phelan D, Desai MY, Tang WH. Isolated left ventricular non-compaction controversies in diagnostic criteria, adverse outcomes and management. Heart 2013;99:681-9. http://dx.doi.org/10.1016/j.echo.2014.06.015
Beware of Life-Threatening Activation of Air Bubble Detector during Contrast Echocardiography in Patients on Venoarterial Extracorporeal Membrane Oxygenator Support To the Editor: Venoarterial extracorporeal membrane oxygenation (ECMO) is a temporizing therapy for patients with refractory cardiogenic shock, and it may also be a bridge to destination therapy or cardiac transplantation. Patients requiring venoarterial ECMO are, by definition, on the verge of cardiopulmonary collapse. Acute disruption of forward flow in ECMO-dependent patients will result in severe hypoperfusion and must be avoided at all costs.1 It is common practice to use contrast transthoracic echocardiography to improve the visualization of endocardial borders and allow more accurate assessments of ventricular function.2-4 This information is used clinically to determine whether to wean patients from ECMO support. The ECMO system used at our institution (CARDIOHELP; MAQUET Medical Systems USA, Wayne, NJ) has an integrated sensor that uses ultrasound to detect changes in flow dynamics associated with the presence of air bubbles or thrombi >5 mm in dimension. Activation of the bubble detector results in an alarm, followed by pump shutdown. If the alarm is not overridden within 6 sec, ‘‘zero-flow mode’’ is engaged. This mode applies sufficient revolutions per minute to prevent backflow from the arterial cannula into the venous cannula and prevents forward flow as well, hence the name zero-flow mode. This safety feature is designed to prevent deleterious cardiovascular and neurologic sequelae associated with air embolism during ECMO. Nevertheless, although this is a safety feature, stopping the ECMO circuitry and therefore the blood flow may be followed by deleterious consequences such as hypotension or the occurrence of thrombi.
Correspondence 1131
Journal of the American Society of Echocardiography Volume 27 Number 10
Although the administration of contrast agents has been deemed safe, we have had two instances at our institution in which the peripheral administration of a microbubble contrast agent, namely, Definity (perflutren lipid microsphere; Lantheus Medical Imaging, North Billerica, MA) during contrast transthoracic echocardiography resulted in activation of the ECMO bubble detector alarm and subsequent engagement of zero-flow mode, resulting in hemodynamic instability.5 Expedient restoration of flow is necessary to avoid grave hemodynamic consequences in patients who are already refractory to maximum inotropic and vasopressor therapy, as well as organ ischemia and circuit thrombosis. However, the need to restore forward flow must be balanced with the need to detect and prevent arterial embolization. We believe that the cause of the air bubble alarm in these cases was the administration of a contrast medium specifically designed to enhance ultrasonographic imaging, which magnified the signal perceived by the air bubble detector. It seems intuitive that the administration of echocardiographic contrast could create an ultrasonographic pattern consistent with turbulent flow that may be interpreted by the sensor as an embolus or a similar occurrence. In any case, it is detected as an event worthy of alarm that requires immediate clinical evaluation to prevent a shutdown for safety reasons. An unexpected alarm of this level of clinical significance should not be haphazardly silenced or overridden. Further investigation into the circumstances surrounding these incidents revealed several learning points that may be helpful in anticipating and avoiding similar events in the future. Safely proceeding with contrast echocardiography in an ECMO patient requires that the provider anticipate and plan for potential sensor alarms and their downstream consequences, including engaging a zero-flow state. We recommend that the circuit be inspected visually before contrast administration, to minimize the chance of a true embolic event being disregarded as an artifact. An experienced team should be present during the study and should include, if possible, the attending cardiothoracic surgeon, the intensivist, and the perfusionist in addition to the
echocardiography team. If possible, contrast transthoracic echocardiography in ECMO patients should be performed during regular working hours, when an abundance of resources and personnel are readily available to aptly handle such occurrences; other possible approaches are to completely avoid the use of contrast agents in ECMO patients and to temporarily disconnect the bubble alarm while a study is under way. In any event, further data are needed before a valid decision can be made on the best way to proceed in these circumstances.
Loreta Grecu, MD Michael A. Fishman, MD, MBA Yale University School of Medicine, Department of Anesthesiology New Haven, Connecticut REFERENCES 1. Allen S, Holena D, McCunn M, Kohl B, Sarani B. A review of the fundamental principles and evidence base in the use of extracorporeal membrane oxygenation (ECMO) in critically ill adult patients. J Intensive Care Med 2011;26:13-26. 2. Bhatia VK, Senior R. Contrast echocardiography: evidence for clinical use. J Am Soc Echocardiogr 2008;21:409-16. 3. Shah BN. Echocardiography in the era of multimodality cardiovascular imaging. Biomed Res Int 2013;2013:310483. 4. Wei K, Mulvagh SL, Carson L, Davidoff R, Gabriel R, Grimm RA, et al. The safety of Definity and Optison for ultrasound image enhancement: a retrospective analysis of 78,383 administered contrast doses. J Am Soc Echocardiogr 2008;21:1202-6. 5. Platts D, Fraser JF, Mullany D, Burstow D. Left ventricular endocardial definition enhancement using perflutren microsphere contrast echocardiography during peripheral venoarterial extracorporeal membranous oxygenation. Echocardiography 2010;27:E112-4. http://dx.doi.org/10.1016/j.echo.2014.06.010
