Wilco Tanis

CT Angiography and 18F-FDG-PET Fusion Imaging for Prosthetic Heart Valve Endocarditis

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)][1]. In

Differentiation of thrombus from pannus as the cause of acquired mechanical prosthetic heart valve obstruction by non-invasive imaging: a review of the literature

AIMS For acquired mechanical prosthetic heart valve (PHV) obstruction and suspicion on thrombosis, recently updated European Society of Cardiology guidelines advocate the confirmation of thrombus by transthoracic echocardiography, transesophageal echocardiography (TEE), and fluoroscopy. However, no evidence-based diagnostic algorithm is available for correct thrombus detection, although this is clinically important as fibrinolysis is contraindicated in non-thrombotic obstruction (isolated pannus). Here, we performed a review of the literature in order to propose a diagnostic algorithm. METHODS AND RESULTS We performed a systematic search in Pubmed and Embase. Included publications were assessed on methodological quality based on the validated Quality Assessment of Diagnostic Accuracy Studies (QUADAS) II checklist. Studies were scarce (n = 15) and the majority were of moderate methodological quality. In total, 238 mechanical PHVs with acquired obstruction and a reliable reference standard were included for the evaluation of the role of fluoroscopy, echocardiography, or multidetector-row computed tomography (MDCT). In acquired PHV obstruction caused by thrombosis, mass detection by TEE and leaflet restriction detected by fluoroscopy were observed in the majority of cases (96 and 100%, respectively). In contrast, in acquired PHV obstruction free of thrombosis (pannus), leaflet restriction detected by fluoroscopy was absent in some cases (17%) and mass detection by TEE was absent in the majority of cases (66%). In case of mass detection by TEE, predictors for obstructive thrombus masses (compared with pannus masses) were leaflet restriction, soft echo density, and increased mass length. In situations of inconclusive echocardiography, MDCT may correctly detect pannus/thrombus based on the morphological aspects and localization. CONCLUSION In acquired mechanical PHV obstruction without leaflet restriction and absent mass on TEE, obstructive PHV thrombosis cannot be confirmed and consequently, fibrinolysis is not advised. Based on the literature search and our opinion, a diagnostic algorithm is provided to correctly identify non-thrombotic PHV obstruction, which is highly relevant in daily clinical practice.

Multimodality Imaging Assessment of Prosthetic Heart Valves

Echocardiography and fluoroscopy are the main techniques for prosthetic heart valve (PHV) evaluation, but because of specific limitations they may not identify the morphological substrate or the extent of PHV pathology. Cardiac computed tomography (CT) and magnetic resonance imaging (MRI) have emerged as new potential imaging modalities for valve prostheses. We present an overview of the possibilities and pitfalls of CT and MRI for PHV assessment based on a systematic literature review of all experimental and patient studies. For this, a comprehensive systematic search was performed in PubMed and Embase on March 24, 2015, containing CT/MRI and PHV synonyms. Our final selection yielded 82 articles on surgical valves. CT allowed adequate assessment of most modern PHVs and complemented echocardiography in detecting the obstruction cause (pannus or thrombus), bioprosthesis calcifications, and endocarditis extent (valve dehiscence and pseudoaneurysms). No clear advantage over echocardiography was found for the detection of vegetations or periprosthetic regurgitation. Whereas MRI metal artifacts may preclude direct prosthesis analysis, MRI provided information on PHV-related flow patterns and velocities. MRI demonstrated abnormal asymmetrical flow patterns in PHV obstruction and allowed prosthetic regurgitation assessment. Hence, CT shows great clinical relevance as a complementary imaging tool for the diagnostic work-up of patients with suspected PHV obstruction and endocarditis. MRI shows potential for functional PHV assessment although more studies are required to provide diagnostic reference values to allow discrimination of normal from pathological conditions.

Imaging of Prosthetic Heart Valve Dysfunction: Complementary Diagnostic Value of TEE and MDCT?

prosthetic heart valves are increasingly implanted worldwide to replace diseased native valves. Prosthetic heart valve (PHV) dysfunction is rare but potentially life-threatening. In clinical practice, transthoracic echocardiography and transesophageal echocardiography, and fluoroscopy for mechanical

Positron Emission Tomography/Computed Tomography for Diagnosis of Prosthetic Valve Endocarditis

Please cite this article as: Tanis W, Scholtens A, Habets J, van den Brink RBA, van Herwerden LA, Chamuleau SAJ, Budde RPJ, Letter to the editor: Positron Emission Tomography/Computed Tomography for Diagnosis of Prosthetic Valve Endocarditis: Increased Valvular 18F-Fluorodeoxyglucose Uptake as a Novel Major Criterion, Journal of the American College of Cardiology (2013), doi: 10.1016/ j.jacc.2013.06.069.

18F-fluorodeoxyglucose positron emission/computed tomography and computed tomography angiography in prosthetic heart valve endocarditis: from guidelines to clinical practice

The timely diagnosis of prosthetic heart valve endocarditis remains challenging yet of utmost importance. 18F-fluorodeoxyglucose (18 F-FDG) positron emission/computed tomography (PET/CT) and cardiac computed tomography angiography (CTA) were recently introduced as additional diagnostic tools in the most recent ESC guidelines on infective endocarditis. However, how to interpret PET/CT findings with regard to what is to be considered abnormal, what the potential confounders may be, as well as which patients benefit most from these additional imaging techniques and how to best perform them in these often-complex patients, remains unclear. This review focusses on factors regarding patient selection and image acquisition that need to be taken into account when employing 18F-FDG PET/CT and CTA in daily clinical practice, and the importance of a multidisciplinary Endocarditis Team herein. Furthermore, it emphasizes the need for standardized acquisition protocols and image interpretation, especially now that these techniques are starting to be widely embraced by the cardiovascular society.

Anticoagulant bridging in left-sided mechanical heart valve patients

BACKGROUND In preparation for an invasive procedure with a high bleeding risk, patients with a mechanical heart valve temporarily have to discontinue their anticoagulant therapy and are usually bridged with either intravenous unfractionated heparin (UFH) or subcutaneous low-molecular-weight heparin (LMWH). In this study we retrospectively analyzed the safety of UFH versus LMWH as bridging strategy in left-sided mechanical heart valve patients. METHODS We performed a retrospective multicenter study in four surgical centers in The Netherlands. Patients with a mechanical heart valve implantation bridged from January 2010 until January 2015 were included. The cumulative incidence of adverse events in the 30days following the procedure was recorded. Main outcomes were major bleeding according to International Society on Thrombosis and Haemostasis (ISTH) criteria, symptomatic thromboembolism, and mortality. RESULTS In total, 238 (174 aortic, 42 mitral, 22 aortic+mitral) bridging episodes were included. The incidence of major bleeding was 16 (19%) events in the UFH group versus 29 (19%) events in the LMWH group (p=0.97). Incidences of thromboembolism were 2 (2.4%) versus 1 (0.6%). The incidence of death was 1 (1.2%) patient in the UFH group versus 3 (1.9%) patients in the LMWH group. More than 50% of all bleeding complications were categorized as a major bleeding. CONCLUSIONS Bridging anticoagulation in patients with aortic and mitral mechanical valves is associated with considerable risk, but no difference was apparent between UFH and LMWH strategy. The rate of thromboembolism and death was low with either strategy and the vast majority of adverse events were bleedings.

The Silence of the Leaflets

A 63-year-old man with a bileaflet mechanical aortic-valve replacement presented with a 3-week history of no audible leaflet clicks. Since he had undergone valve placement 6 years earlier, the clicks had always been clearly audible.

Improving the diagnostic performance of 18F-FDG PET/CT in prosthetic heart valve endocarditis

Background: 18F-Fluorodeoxyglucose (FDG) positron-emission tomography/computed tomography (PET/CT) was recently introduced as a new tool for the diagnosis of prosthetic heart valve endocarditis (PVE). Previous studies reporting a modest diagnostic accuracy may have been hampered by unstandardized image acquisition and assessment, and several confounders, as well. The aim of this study was to improve the diagnostic performance of FDG PET/CT in patients in whom PVE was suspected by identifying and excluding possible confounders, using both visual and standardized quantitative assessments. Methods: In this multicenter study, 160 patients with a prosthetic heart valve (median age, 62 years [43–73]; 68% male; 82 mechanical valves; 62 biological; 9 transcatheter aortic valve replacements; 7 other) who underwent FDG PET/CT for suspicion of PVE, and 77 patients with a PV (median age, 73 years [65–77]; 71% male; 26 mechanical valves; 45 biological; 6 transcatheter aortic valve replacements) who underwent FDG PET/CT for other indications (negative control group), were retrospectively included. Their scans were reassessed by 2 independent observers blinded to all clinical data, both visually and quantitatively on available European Association of Nuclear Medicine Research Ltd–standardized reconstructions. Confounders were identified by use of a logistic regression model and subsequently excluded. Results: Visual assessment of FDG PET/CT had a sensitivity/specificity/positive predictive value/negative predictive value for PVE of 74%/91%/89%/78%, respectively. Low inflammatory activity (C-reactive protein <40 mg/L) at the time of imaging and use of surgical adhesives during prosthetic heart valve implantation were significant confounders, whereas recent valve implantation was not. After the exclusion of patients with significant confounders, diagnostic performance values of the visual assessment increased to 91%/95%/95%/91%. As a semiquantitative measure of FDG uptake, a European Association of Nuclear Medicine Research Ltd–standardized uptake value ratio of ≥2.0 was a 100% sensitive and 91% specific predictor of PVE. Conclusions: Both visual and quantitative assessments of FDG PET/CT have a high diagnostic accuracy in patients in whom PVE is suspected. FDG PET/CT should be implemented early in the diagnostic workup to prevent the negative confounding effects of low inflammatory activity (eg, attributable to prolonged antibiotic therapy). Recent valve implantation was not a significant predictor of false-positive interpretations, but surgical adhesives used during implantation were.Laurens E. Swart, MD; Anna Gomes, MD, PhD; Asbjørn M. Scholtens, MD; Bhanu Sinha, MD, PhD; Wilco Tanis, MD, PhD; Marnix G.E.H. Lam, MD, PhD; Maureen J. van der Vlugt, MD, PhD; Sebastian A.F. Streukens, MD; Erik H.J.G. Aarntzen, PhD; Jan Bucerius, MD, PhD; Sander van Assen, MD, PhD; Chantal P. Bleeker-Rovers, MD, PhD; Peter Paul van Geel, MD, PhD; Gabriel P. Krestin, MD, PhD; Joost P. van Melle, MD, PhD, Jolien W. Roos-Hesselink, MD, PhD; Riemer H.J.A. Slart, MD, PhD; Andor W.J.M. Glaudemans, MD, PhD; Ricardo P.J. Budde MD PhD

UNFRACTIONATED HEPARIN VERSUS LOW-MOLECULAR-WEIGHT HEPARIN ANTICOAGULANT BRIDGING IN LEFT-SIDED MECHANICAL HEART VALVE PATIENTS: THE HI-LOW STUDY

In anticipation of an invasive procedure with a high bleeding risk, patients with a mechanical heart valve are bridged with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). However, there is no consensus regarding the ideal strategy, and prospective studies are lacking.