Response to Letter Regarding Article, “Unreliable Assessment of Necrotic Core by Virtual Histology Intravascular Ultrasound in Porcine Coronary Artery Disease”
2010; Lippincott Williams & Wilkins; Volume: 3; Issue: 5 Linguagem: Inglês
10.1161/circimaging.110.958652
ISSN1942-0080
AutoresTroels Thim, Mette K. Hagensen, David Wallace-Bradley, Juan F. Granada, Greg L. Kałuża, Ludovic Drouet, William P. Paaske, Hans Erik Bøtker, Erling Falk,
Tópico(s)Acute Myocardial Infarction Research
ResumoHomeCirculation: Cardiovascular ImagingVol. 3, No. 5Response to Letter Regarding Article, "Unreliable Assessment of Necrotic Core by Virtual Histology Intravascular Ultrasound in Porcine Coronary Artery Disease" Free AccessReplyPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReplyPDF/EPUBResponse to Letter Regarding Article, "Unreliable Assessment of Necrotic Core by Virtual Histology Intravascular Ultrasound in Porcine Coronary Artery Disease" Troels Thim, Mette Kallestrup Hagensen, David Wallace-Bradley, Juan F. Granada, Greg L. Kaluza, Ludovic Drouet, William P. Paaske, Hans Erik Bøtker and Erling Falk Troels ThimTroels Thim , Mette Kallestrup HagensenMette Kallestrup Hagensen , David Wallace-BradleyDavid Wallace-Bradley , Juan F. GranadaJuan F. Granada , Greg L. KaluzaGreg L. Kaluza , Ludovic DrouetLudovic Drouet , William P. PaaskeWilliam P. Paaske , Hans Erik BøtkerHans Erik Bøtker and Erling FalkErling Falk Originally published1 Sep 2010https://doi.org/10.1161/CIRCIMAGING.110.958652Circulation: Cardiovascular Imaging. 2010;3:e5We appreciate this opportunity to respond to the comments provided by Drs Gregg Stone and Gary Mintz. They question the conclusion of our study, in which no correlation was found between the size of the necrotic core determined by virtual histology intravascular ultrasound (VH IVUS) and real histology in a porcine model of coronary artery disease.1First, Drs Stone and Mintz stress the importance of reliable alignment and matching of corresponding images and state that " … it is inappropriate to align a given histological section to an IVUS frame and expect high correlation in quantification of individual tissue components." We acknowledge the potential limitations of such alignment, but we do not agree that the method is inappropriate, because this approach forms the general base for validation of VH IVUS for quantitative tissue mapping.2,3Second, Drs Stone and Mintz argue that our result is driven primarily by 1 point in Figure 1A (absolute values), called an outlier. Because the data were not normally distributed, even after transformation, we used Spearman's rho and not Pearson's r. If the data point in question is removed, the correlation between the absolute values becomes just statistically significant (Spearman's rho 0.50, P=0.04), but it becomes nonsignificant again if the next "outlier" (data point to the far right) is removed. We used an unbiased approach in our analyses and found no reason to exclude any data points. More important, the relative and not absolute necrotic core size is used to detect vulnerable plaques by VH IVUS, and removal of any potential outliers in Figure 1B (relative values) does not change our conclusion.Third, the reliability of histologic assessment by "highly experienced cardiac pathologists" is questioned. High reproducibility, even among experts, requires accurate and unambiguous definitions and appropriate methods that are not always appreciated. In the unpublished study mentioned by Drs Stone and Mintz, we do not know how the necrotic core was defined, but the method used to detect it (Movat stain alone) was not appropriate. We defined the necrotic core accurately (total loss of collagen, which is the reason for instability) and used an appropriate histologic stain to detect it (picrosirius red).Fourth, Drs Stone and Mintz state that necrotic cores, characterized by a total loss of collagen, are often hyperechoic. Here we come to the core of the matter, and not a single reference is provided for this view. Clinically, vulnerable coronary plaques tend to be echolucent on gray-scale IVUS.4 We are aware that the authors have previously reported that echolucent areas on gray-scale IVUS never appear red (necrotic core) by VH IVUS,5 which is in agreement with our findings. However, in contrast to the prevailing view, red on VH IVUS did not correspond to the necrotic core by real histology.Fifth, Drs Stone and Mintz question the relevance of our porcine model. This potential limitation was acknowledged and discussed in our article. Regarding the necrotic core, it is difficult to understand why and how a total loss of collagen, replaced by lipid-rich necrosis and detected by IVUS, should differ substantially between patients and adult swine with the same disease.Sixth, the significance and reliability of so-called "geometric transformation" remain elusive. It is reassuring that our conclusion is based on both absolute and relative necrotic core measures.Last, although our study did not test the prognostic utility of the color-coded tissue maps provided by VH IVUS in humans, it does question the current interpretation of such maps.Troels Thim, MD Atherosclerosis Research Unit, Department of Cardiology Aarhus University Hospital Skejby, Denmark Institute of Clinical Medicine Aarhus University Aarhus, Denmark Jack H. Skirball Center for Cardiovascular Research Cardiovascular Research Foundation New York, NYMette Kallestrup Hagensen, MSc Atherosclerosis Research Unit, Department of Cardiology Aarhus University Hospital Skejby, Denmark Institute of Clinical Medicine Aarhus University Aarhus, DenmarkDavid Wallace-Bradley, MScJuan F. Granada, MDGreg L. Kaluza, MD, PhD Jack H. Skirball Center for Cardiovascular Research Cardiovascular Research Foundation New York, NYLudovic Drouet, MD, PhD Institut des Vaisseaux et du Sang Paris, FranceWilliam P. Paaske, MD, DMSc Department of Cardiothoracic and Vascular Surgery Aarhus University Hospital (Skejby) Aarhus, DenmarkHans Erik Bøtker, MD, PhD, DMSc Department of Cardiology Aarhus University Hospital (Skejby) Aarhus, DenmarkErling Falk, MD, DMSc Atherosclerosis Research Unit, Department of Cardiology Aarhus University Hospital Skejby, Denmark Institute of Clinical Medicine Aarhus University Aarhus, DenmarkDisclosuresNone.References1. Thim T, Hagensen MK, Wallace-Bradley D, Granada JF, Kaluza GL, Drouet L, Paaske WP, Botker HE, Falk E. Unreliable assessment of necrotic core by virtual histology intravascular ultrasound in porcine coronary artery disease. Circ Cardiovasc Imaging. 2010; 3:384–391.LinkGoogle Scholar2. Nair A, Kuban BD, Tuzcu EM, Schoenhagen P, Nissen SE, Vince DG. Coronary plaque classification with intravascular ultrasound radiofrequency data analysis. Circulation. 2002; 106:2200–2206.LinkGoogle Scholar3. Nair A, Margolis M, Kuban B, Vince D. Automated coronary plaque characterisation with intravascular ultrasound backscatter: ex vivo validation. EuroIntervention. 2007; 3:113–120.MedlineGoogle Scholar4. Yamagishi M, Terashima M, Awano K, Kijima M, Nakatani S, Daikoku S, Ito K, Yasumura Y, Miyatake K. Morphology of vulnerable coronary plaque: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary syndrome. J Am Coll Cardiol. 2000; 35:106–111.CrossrefMedlineGoogle Scholar5. Maehara A. Virtual histology 2: interesting observations from registries. Available at: http://www.tctmd.com/txshow.aspx?tid=938870&id=82802&trid=938634. Last accessed June 16, 2010.Google Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Abudayyeh I, Tran B and Tobis J (2017) Optimizing Coronary Angioplasty with FFR and Intravascular Imaging, Current Cardiovascular Risk Reports, 10.1007/s12170-017-0534-9, 11:2, Online publication date: 1-Feb-2017. September 2010Vol 3, Issue 5 Advertisement Article InformationMetrics © 2010 American Heart Association, Inc.https://doi.org/10.1161/CIRCIMAGING.110.958652 Originally publishedSeptember 1, 2010 PDF download Advertisement
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