Author + information
- Wilco Tanis, MD∗∗ (, )
- Asbjørn Scholtens, MD†,
- Jesse Habets, MD, PhD‡,
- Renee B.A. van den Brink, MD, PhD§,
- Lex A. van Herwerden, MD, PhD||,
- Steven A.J. Chamuleau, MD, PhD∗ and
- Ricardo P.J. Budde, MD, PhD‡
- ∗Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
- †Department of Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands
- ‡Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands
- §Department of Cardiology, Academic Medical Center, Amsterdam, the Netherlands
- ||Department of Cardiothoracic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands
- ↵∗Address for correspondence:
Dr. Wilco Tanis, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, the Netherlands.
IN PROSTHETIC HEART VALVE (PHV) ENDOCARDITIS, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) may occasionally fail to recognize vegetations and periannular extensions (abscesses/mycotic aneurysms) due to acoustic shadowing by the metal PHV ring (1). In approximately 50% of cases, PHV endocarditis is complicated by periannular extensions, which is an indication for urgent surgery in order to improve survival (1). Additional imaging with retrospectively electrocardiogram-gated computed tomography angiography (CTA) or 18F-fluorodeoxyglucose positron emission tomography including low-dose computed tomography (FDG-PET/CT) and a low-carbohydrate diet improve diagnostic accuracy. However, PHV endocarditis may still be missed by both individual diagnostic tools (2,3). Combining or even fusing both diagnostic tools results in state-of-the-art high-resolution anatomic and metabolic imaging of the PHV and its surrounding anatomy, which may be the desired imaging strategy in patients with suspicion of PHV endocarditis. Furthermore, whole-body FDG-PET/CT can detect primary foci or metastatic infections in PHV endocarditis, which may have therapeutic consequences as well.
FDG-PET/CT and CTA imaging independently are promising tools to correctly diagnose PHV endocarditis in patients with a negative or inconclusive routine work-up with TTE and TEE (2,3). FDG-PET with localizing lowdose CT for attenuation correction is able to detect periannular extensions of PHV endocarditis in which standardized uptake value (SUV) ratios may be of additional help. All presented and surgically confirmed cases with periannular extensions had a SUV ratio of more than 3.5 and a SUV maximum of more than 6.8. As reported in the literature and shown in this case series, FDG-PET alone may miss highly mobile vegetations, probably due to its low spatial resolution. Furthermore, the low-dose CT that comes with FDG-PET is not electrocardiogram gated nor contrast enhanced, and therefore unable to detect vegetations. For this reason, an additional CTA may be of complementary value to detect, not only vegetations, but also anatomic aortic root abnormalities and coronary artery obstructions. CTA may sometimes replace invasive coronary angiography, which is desired in aortic PHV endocarditis with vegetations. In conclusion, in addition to echocardiography, the independent, combined, or even fused use of FDG-PET/CT and CTA may have complementary beneficial value in patients with PHV endocarditis and may guide therapeutic strategies (Figs. 1 to 7⇓⇓⇓⇓⇓).
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This work was supported by a grant from the Dutch Heart Foundation (NHS 2009B014). Dr. van Herwerden has been a consultant to and on the review board for St. Jude Medical, for which he received <$10,000. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation