Ann Thorac Surg 2009;87:359-360. doi:10.1016/j.athoracsur.2008.10.094
© 2009 The Society of Thoracic Surgeons
Editorials
Guidelines for Reporting Mortality and Morbidity After Cardiac Valve Interventions—Need for a Reappraisal? (Response)
Cary W. Akins, MDa,*,
Eugene H. Blackstone, MDb,
D. Craig Miller, MDc,
Nicholas T. Kouchoukos, MDd,
Marko I. Turina, MDe
a Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts
b Department of Thoracic and Cardiovascular Surgery, Heart and Vascular Institute, The Cleveland Clinic Foundation, Cleveland, Ohio
c Department of Cardiovascular and Thoracic Surgery, Stanford University School of Medicine, Stanford, California
d Cardiac, Thoracic and Vascular Surgery Inc, St. Louis, Missouri
e Department of Surgery, University Hospital Zurich, Zurich, Switzerland
* Address correspondence to Dr Akins, Massachusetts General Hospital, Cardiac Surgery - White 503, 55 Fruit St, Boston, MA 02114 (Email: cakins{at}partners.org).
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Introduction
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Piazza and colleagues have provided a thoughtful and thought-provoking response to our recently published "Guidelines for Reporting Mortality and Morbidity After Cardiac Valve Interventions" [1] that focuses particularly on their application to the burgeoning field of percutaneous valve interventions. They listed four points that they believe require further discussion: (1) morbidity definitions, (2) approach-specific outcome measures, (3) composite end points, and (4) implications for transcatheter therapy. We will try to address their concerns about each of these issues.
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Morbidity Definitions
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As a general comment: For what we thought were valid reasons, the current guidelines intentionally do not provide rigorous, complete definitions of each complication. Definitions that are too specific risk becoming rapidly antiquated in the face of both advancing technology and ongoing work of other bodies that establish standards, such as the Society of Thoracic Surgeons National Database Committee, charged with such definitions. For example, Piazza and colleagues mention the new definition of myocardial infarction [2]. If that document had been written when the best available enzyme determination was the myocardial fraction of creatine kinase, how would they have adapted to the newer and better measurement of troponin? Definitions that are too strict fail to keep pace with advances in medicine and are useful for only a brief period of time. They become exclusive, not inclusive.
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Approach-Specific Outcome Measures
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The guidelines are meant to focus on complications and outcomes occurring after cardiac valve interventions, not complications of the procedure itself. The editorial writers list other outcomes, such as renal or respiratory failure and length of stay, that apply to any cardiac intervention and are not heart valve-specific. These general outcomes have less to do with the valve intervention itself and more to do with patient-specific variables [3].
Although the guidelines list complications that need to be addressed, they do not limit authors from adding additional end points. These guidelines are meant to be comprehensive of all valve-related adverse events.
The editorialists then ask three specific questions about outcomes, which we will answer:
- 1 New onset coronary ischemia from coronary ostial obstruction that occurs after the intervention is not a problem due to deterioration of the prosthesis and thus is not structural valve deterioration; that is, it is not directly related to a change in intrinsic properties of the prosthesis itself.
- 2 Clinically important hemolytic anemia is anemia that results in transfusion, heart failure, or hospitalization.
- 3 Interventional manipulation is any open, but more likely transcatheter, intervention that in any way directly changes a prosthesis or valve repair.
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Composite End Points
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The use of actuarial event-free rates of complications is more of a patient-related approach in contrast to a device-related approach. The issue of composite end points is broader than this, however. Composite end points give each factor included equal importance. We strongly disagree with that general concept. Transfusion of a unit of blood to correct anticoagulant-related gastrointestinal bleeding that yields no sequelae would not be comparable to a large thromboembolic stroke that results in permanent physical impairment.
Nevertheless, for example, although thrombosis, embolism, and bleeding events need to be reported separately, we have suggested reporting the composite of thrombosis, embolism, and bleeding because it represents a way to view two sides of the same coin, namely, heart valve thrombogenicity and the requirement for anticoagulation. Further, these guidelines are meant to help clinicians investigate differences among prostheses or therapeutic approaches, not to attempt to make those devices or techniques appear similar. Composite end points can blur distinctions between devices or techniques.
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Implications for Transcatheter Therapy
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Our guidelines, which are now in their third iteration, represent decades of surgical experience with cardiac valve interventions. Transcatheter valve therapies are currently only nascent, experimental techniques. We would suggest that if transcatheter valve therapies are to replace standard surgical treatments, proof of their safety and efficacy is imperative. They also should be held to the existing standards to which surgical procedures and implanted prostheses are subjected. For example, the writers point out that a mild degree of paravalvular leakage is often observed after percutaneous valve insertion, and reporting this "may give a wrong impression of the functional performance of the prosthesis."
We strongly disagree with this position. If there were ever a time that we should pay particular attention to real or potential problems, it is when new devices or techniques are introduced. There should be no "blanking periods" or blinders to findings, even if they are thought to be benign—and it is far too early to claim they are benign [4]! Although experience suggests that the prevalence of complications associated with early implants will be reduced as technology advances, that does not mean that experimental technologies should be held to lesser standards.
As a final note, the authors remind us of details that never appear in guidelines: hours of work, wrestling with issues, arriving at compromise and consensus, making decisions about what should and should not be included in the guidelines, considering how the guidelines might be interpreted by regulatory organizations such as the Food and Drug Administration, attempting to clarify items that have proved to be confusing, and keeping the guidelines current with advances, not only of the devices themselves but also of statistical methods for analyses of outcomes. Feedback such as this letter is important in crystallizing our thoughts and providing guidance for the next round of guidelines construction.
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Footnotes
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For related article, see page 357
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References
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- Akins CW, Miller DC, Turina MI, et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions Ann Thorac Surg 2008;85:1490-1495.[Free Full Text]
- Thygesen K, Alpert JS, White HD, et al. Universal definition of myocardial infarction Circulation 2007;116:2634-2653.[Free Full Text]
- Silber JH, Rosenbaum PR, Schwartz JS, Ross RN, Williams SV. Evaluation of the complication rate as a measure of quality of care in coronary artery bypass graft surgery JAMA 1995;274:317-323.[Abstract/Free Full Text]
- Akins CW, Bitondo JM, Hilgenberg AD, Vlahakes GJ, Madsen JC, MacGillivray TE. Early and late results of the surgical correction of cardiac prosthetic paravalvular leaks J Heart Valve Dis 2005;14:792-799discussion 799-800.[Medline]
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Guidelines for Reporting Mortality and Morbidity After Cardiac Valve Interventions—Need for a Reappraisal?
- Nicolo Piazza, Yoshinobu Onuma, Peter de Jaegere, and Patrick W. Serruys
Ann. Thorac. Surg. 2009 87: 357-358.
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L. H. Edmunds Jr
Editor's Note.
Ann. Thorac. Surg.,
February 1, 2009;
87(2):
360 - 360.
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Introduction
Morbidity Definitions