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Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, the Netherlands
* Address correspondence to Dr Serruys, Department of Cardiology, Erasmus Medical Center, Thoraxcenter, Ba583a, Erasmus MC, 's-Gravendijkwal 230, Rotterdam, 3015 CE, the Netherlands (Email: p.w.j.c.serruys{at}erasmusmc.nl).
The published guidelines by Akins and colleagues for reporting mortality and morbidity after cardiac valvar intervention represent an important update since they were last published in 1996 [1]. Novel techniques and methods to treat valvar heart disease have emerged recently, in particular, transcatheter valve therapies. The updated guidelines are intended to apply "uniformly" to conventional open operation, minimally invasive (video-assisted or robotic) surgical procedures, and transcatheter valve therapies. The Councils of the American Association for Thoracic Surgery, The Society of Thoracic Surgeons, and The European Association for Cardio-Thoracic Surgery decided upon an Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity. The authors of the guidelines are key experts in the field of cardiac surgery.
According to the authors, the guidelines are to facilitate the analysis and reporting of clinical studies of various therapeutic approaches to valvar heart disease such that meaningful comparisons can be made and inferences drawn from these studies. In its present context, the guidelines are limited to fulfill their intended purpose. The following points require further discussion: (1) refinement of the definitions of heart valve morbidity, (2) an extension of the list of outcome measures, including outcome measures particular to each therapeutic approach, (3) consideration to the reporting of device-oriented and patient-oriented composite end points, and (4) the implications of applying these guidelines to transcatheter valve therapies.
The collaborative works on the universal definitions of stent thrombosis and myocardial infarction exemplify the importance of guidelines to be clear, consistent, and objective for the purposes of collecting and interpreting the results of clinical trials [2, 3]. To maintain their integrity and validity, guidelines need to be updated frequently. Vaguely defined outcome measures can be an important source of misinterpretation of results and conclusions of studies. The definitions of morbidity outcomes used in the present guidelines tend to generate many questions. Amongst others:
In the absence of definitions, references to the literature could have been made.
Despite the existence of these guidelines, significant variability still exists in the reporting of morbidity and mortality after surgical aortic valve replacement. This heterogeneous reporting of results can also make comparison of studies quite challenging [4–10].
Conspicuously missing from the current guidelines are the definitions of stroke from causes other than embolism (eg, thrombosis, hemorrhage, or watershed), myocardial infarction from causes other than coronary arterial obstruction (eg, thrombosis, embolism, or low perfusion pressure), renal failure, respiratory failure, sepsis, arrhythmia/conduction abnormalities, and length of hospital stay. In particular to transcatheter aortic valve therapies, morbidity outcomes such as aortic dissection from delivery catheter systems, ventricular perforation and cardiac tamponade, valve embolization, and peripheral vascular complications (associated major and minor bleeding) should be included. These complications can affect the quality of life of patients after the procedure and should be encapsulated in the guidelines. Similar considerations would be required for transcatheter therapies of the pulmonary and mitral valve.
Outcome measures of safety and effectiveness are crucial for the short- and long-term evaluation of heart valve devices. Measures of safety should reflect any adverse outcome whether or not directly related to the device. The incorporation of device-oriented and patient-oriented composite end points can be useful to provide greater statistical power to detect potentially meaningful statistical differences between therapies [2]. Device-oriented composite end points can include cardiac death, myocardial infarction, and stroke related to the procedure or device, and a repeat procedure during the index hospitalization. Patient-oriented composite end points can include all-cause mortality, and myocardial infarction, and stroke from any cause.
Application of the current guidelines to transcatheter aortic valve therapies can have a negative effect on the perception of the technology despite the recent, encouraging clinical results. According to the guidelines, nonstructural dysfunction was defined as any abnormality not intrinsic to the valve itself that results in stenosis or regurgitation, and for transcatheter approaches to implantation of the aortic valve, also includes paravalvular aortic regurgitation. Currently available literature would suggest that nonstructural dysfunction of percutaneous aortic valves would be in excess of 50% [11–13]. Aortic regurgitation has been reported in 6% to 48% of patients after surgical aortic valve replacement [14, 15]. Ionescu and colleagues [14] noted, "small paraprosthetic leaks are common, are related to surgical factors, are not associated with increased subclinical hemolysis, and are benign during the first year after heart valve replacement." Similarly, Rallidis and colleagues [15] concluded, "paraprosthetic aortic leaks are common, are usually small, and have a benign course." Reporting the occurrence of aortic regurgitation and its associated adverse effects is unquestionably important.
In another instance, reintervention was defined as any surgical or percutaneous interventional catheter procedure that repairs, otherwise alters or adjusts or replaces a previously implanted prosthesis or repaired valve. Included in this definition is balloon redilatation, interventional manipulation, repositioning, or retrieval. The combination of balloon redilatation and implantation of a second valve can be seen in up to 30% to 35% of patients after transcatheter implantation of the aortic valve [16]. Furthermore, certain second-generation transcatheter valve designs are now presenting the luxury of being "repositionable" or "retrievable," and associating this luxury with a negative label such as "reintervention" would appear unjust.
Despite being in its infancy stages, recent reports are disclosing implantation success rates of 90% to 100% and 30-day mortality rate of approximately 8% [11]. To date, more than 3000 transcatheter aortic valve procedures have been performed worldwide. Application of the proposed guidelines to transcatheter aortic valve therapies would yield rates of nonstructural valve dysfunction of 50% to 100% and rates of reintervention of 30% to 35%. Instead, we may want to continue to individually report rates of paravalvular regurgitation, need for redilatation, implantation of a second valve, and repositioning/retrieval for the sake of clarity.
Finally, estimates indicate the percentage of overall heart valve procedures performed by a transcatheter approach will increase from 0.2% in 2007 to approximately 40% by 2012 [17]. Thus, it would seem reasonable that the development of universal guidelines for the reporting of mortality and morbidity after cardiac valvar interventions should be undertaken by the joint effort of cardiac surgeons and interventional cardiologists. As an extension to this, we would like to introduce the concept of the "heart team," whereby the cardiac surgeon and interventional cardiologist play a complementary role and work as a team in the decision-making process of patients referred for the treatment of aortic stenosis.
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  L. H. Edmunds Jr Editor's Note. Ann. Thorac. Surg., February 1, 2009; 87(2): 360 - 360. [Full Text] [PDF]
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