Evaluation and Management of Mechanical Heart Valve Dysfunction and Thrombosis

PURPOSE OF REVIEW

Dysfunction and thrombosis of mechanical heart valves, although uncommon, represents a challenge that requires multidisciplinary expertise for diagnosis and management. The aim of this review is to summarize strengths and weaknesses of diagnostic methods and therapeutic strategies for this uncommon but potentially life-threatening pathology.

RECENT FINDINGS

Expeditious diagnosis of mechanical valve thrombosis and exclusion of other diagnostic considerations, often with incorporation of multimodality imaging, can inform the best treatment strategy. Presentation of mechanical valve thrombosis can be asymptomatic or can include heart failure, life-threatening embolic events, or cardiogenic shock. Echocardiography, fluoroscopy and computed tomography are important in the evaluation of mechanical valve dysfunction. Therapeutic strategies for thrombosis include anticoagulation, systemic thrombolysis, and surgery. Choice of treatment depends on multiple factors including thrombus size, degree of valve dysfunction, clinical presentation, and available surgical expertise.

Mechanical prosthetic valve thrombosis: A literature review of treatment strategies

Mechanical prosthetic valve thrombosis (MPVT) is a common complication of valvular implantations. This study compared the efficacy and safety of different treatments for MPVT. A systematic search of electronic databases identified studies evaluating surgical, anticoagulant, and thrombolytic therapies. Although several studies of different types have been conducted to evaluate the efficacy of these treatment strategies the lack of randomized controlled trials has resulted in the inability to make a definitive conclusion about the pros and cons of these treatments. Recent treatments, such as slow and ultraslow infusion of thrombolytics, showed comparable efficacy and lower complication rates than traditional methods. Inadequate anticoagulant use is a major risk factor for MPVT, highlighting the importance of prevention. Treatment selection should be individualized based on patient factors and available expertise. Overall, slow and ultraslow infusion of thrombolytics may be a promising treatment option for MPVT.

Dysfunctioning mechanical mitral valve prosthesis: When thrombus over pannus makes hinders diagnosis

Prosthetic valve obstruction is a rare but potentially lethal complication. The most frequent causes are thrombus and pannus formation, in the absence of infectious data. Diagnosis is not always easy using cardiac CT scanning and in 46%-85% of cases thrombus and pannus coexist, complicating the diagnosis. A rapid diagnosis is essential to avoid a fatal outcome of this pathology whose mortality, despite correct treatment, is high.

Mechanical prosthetic mitral valve obstruction: Pannus or thrombus? A case report

Substitution of a defective heart valve with a prosthetic heart valve turns the native disease for prosthesis-related complications. One of the most serious and dreaded complications is prosthetic valve obstruction. It is either the result of a thrombus or pannus formation. For the evaluation of prosthetic valve obstruction, transthoracic echography and fluoroscopy provide functional information but may not provide information about the etiology of the obstruction, unlike multidetector computed tomography (MDCT) which allows a more precise etiological diagnosis to guide the therapeutic attitude. Here, we report a case of a mechanical prosthetic mitral valve obstruction in a 45-year-old patient in whom the diagnosis of pannus was retained on the basis of clinical, biological, and imaging data. The differentiation between thrombus and pannus is crucial because it conditions the therapeutic attitude. Advanced imaging specially MDCT options should be considered whenever mechanical prosthesis valve obstruction is suspected.

Three-dimensional transoesophageal echocardiography: how to use and when to use-a clinical consensus statement from the European Association of Cardiovascular Imaging of the European Society of Cardiology

Three-dimensional transoesophageal echocardiography (3D TOE) has been rapidly developed in the last 15 years. Currently, 3D TOE is particularly useful as an additional imaging modality for the cardiac echocardiographers in the echo-lab, for cardiac interventionalists as a tool to guide complex catheter-based procedures cardiac, for surgeons to plan surgical strategies, and for cardiac anaesthesiologists and/or cardiologists, to assess intra-operative results. The authors of this document believe that acquiring 3D data set should become a 'standard part' of the TOE examination. This document provides (i) a basic understanding of the physic of 3D TOE technology which enables the echocardiographer to obtain new skills necessary to acquire, manipulate, and interpret 3D data sets, (ii) a description of valvular pathologies, and (iii) a description of non-valvular pathologies in which 3D TOE has shown to be a diagnostic tool particularly valuable. This document has a new format: instead of figures randomly positioned through the text, it has been organized in tables which include figures. We believe that this arrangement makes easier the lecture by clinical cardiologists and practising echocardiographers.

Diagnosis of Left-Sided Mechanical Prosthetic Valve Thrombosis: A Pictorial Review

Although transcatheter valve therapy is rapidly evolving, surgical valve replacement is still required in many patients with severe left-side valve stenosis or regurgitation, the mechanical bi-leaflet heart valve being the standard prosthesis type in younger patients. Moreover, the prevalence of valvular heart disease is steadily increasing, especially in industrialized countries, and the problem of lifelong efficient anticoagulation of these patients remains fundamental, especially in the context where vitamin K antagonists continue to be the current standard of anticoagulation despite a level of oscillating anticoagulation. In this setting, avoiding prosthetic valve thrombosis after surgery is the number one objective for both the patient and the responsible physicians. Although rare, this complication is life threatening, with the sudden onset of acute cardiac failure such as acute pulmonary edema, cardiogenic shock, or sudden cardiac death and inadequate anticoagulation remaining the leading cause of prosthesis thrombosis, along with other risk factors. The availability of multimodal imaging techniques enables and encompasses to a full extent the diagnosis of mechanical valve thrombosis. The gold-standard diagnostic methods are transthoracic and transesophageal echocardiography. Moreover, 3D ultrasound has undoubted value in giving a more accurate description of the thrombus's extension. When transthoracic and transesophageal echocardiography are uncertain, the multidetector computer tomography examination is an important complementary imaging method. Fluoroscopy is also an excellent tool for evaluating the mobility of prosthetic discs. Each method complements the other to differentiate an acute mechanical valve thrombosis from other prosthetic valve pathologies such as pannus formation or infective endocarditis and aids the physician in accurately establishing the treatment method (surgical or pharmaceutical) and its optimal timing. The aim of this pictorial review was to discuss from an imagistic perspective the mechanical prosthetic aortic and mitral valve thrombosis and to provide an overview of the essential role of non-invasive exploration in the treatment of this severe complication.

Management of Mechanical Prosthetic Heart Valve Thrombosis: JACC Review Topic of the Week

Mechanical prosthetic heart valves, though more durable than bioprostheses, are more thrombogenic and require lifelong anticoagulation. Mechanical valve dysfunction can be caused by 4 main phenomena: 1) thrombosis; 2) fibrotic pannus ingrowth; 3) degeneration; and 4) endocarditis. Mechanical valve thrombosis (MVT) is a known complication with clinical presentation ranging from incidental imaging finding to cardiogenic shock. Thus, a high index of suspicion and expedited evaluation are essential. Multimodality imaging, including echocardiography, cine-fluoroscopy, and computed tomography, is commonly used to diagnose MVT and follow treatment response. Although surgery is oftentimes required for obstructive MVT, other guideline-recommended therapies include parenteral anticoagulation and thrombolysis. Transcatheter manipulation of stuck mechanical valve leaflet is another treatment option for those with contraindications to thrombolytic therapy or prohibitive surgical risk or as a bridge to surgery. The optimal strategy depends on degree of valve obstruction and the patient's comorbidities and hemodynamic status on presentation.

Cardiac gated multidetector computed tomography (MDCT) to determine valvular leaflet thrombosis and leaflet restriction

The evaluation of patients following aortic valve replacement has evolved, with multiple imaging modalities available that complement each other and permit better and prompt delineation of specific structural or functional valve complications. Multidetector computed tomography (MDCT) is one of the diagnostic modalities with significant technologic advancements that have made possible to evaluate high detail of the moving heart. The ability to deliver three-dimensional and multiplanar dynamic imaging with fine detail has demonstrated the technique is well suited to investigate valve complications. In this review article, we focus on some of the most contributing roles of MDCT in the diagnosis of complications associated with valvular pathology.

Clinical and Surgical Evaluations of Reoperation After Mechanical Mitral Valve Replacement Due to Different Etiologies

Background:

This study aimed to evaluate the clinical and surgical characteristics of patients who required reoperation after mechanical mitral valve replacement (MVR).

Methods:

We retrospectively identified 204 consecutive patients who underwent reoperation after mechanical MVR between 2009 and 2018. Patients were categorized according the reason for reoperation (perivalvular leakage, thrombus formation, or pannus formation). The patients' medical and surgical records were studied carefully and the rates of in-hospital complications were calculated.

Results:

The mean age was 51±12 years and 44% of the patients were male. The reasons for reoperation were perivalvular leakage (117 patients), thrombus formation (35 patients), and pannus formation (52 patients). The most common positions for perivalvular leakage were at the 6–10 o'clock positions (proportions of ≥25% for each hour position). Most patients had an interval of >10 years between the original MVR and reoperation. The most common reoperation procedure was re-do MVR (157 patients), and 155 of these patients underwent concomitant cardiac procedures. There were 10 in-hospital deaths and 32 patients experienced complications. The 10-year survival rate was 82.2 ± 3.9% in general, and the group of lowest rate was patients with PVL (77.5 ± 5.2%). The independent risk factors were “male” (4.62, 95% CI 1.57–13.58, P = 0.005) and “Hb <9g/dL before redo MV operation” (3.45, 95% CI 1.13–10.49, P = 0.029).

Conclusion:

Perivalvular leakage was the most common reason for reoperation after mechanical MVR, with a low survival rate in long term follow-up relatively.

The Role of Multimodality Imaging in Left-Sided Prosthetic Valve Dysfunction

Prosthetic valve (PV) dysfunction (PVD) is a complication of mechanical or biological PV. Etiologic mechanisms associated with PVD include fibrotic pannus ingrowth, thrombosis, structural valve degeneration, and endocarditis resulting in different grades of obstruction and/or regurgitation. PVD can be life threatening and often challenging to diagnose due to the similarities between the clinical presentations of different causes. Nevertheless, identifying the cause of PVD is critical to treatment administration (thrombolysis, surgery, or percutaneous procedure). In this report, we review the role of multimodality imaging in the diagnosis of PVD. Specifically, this review discusses the characteristics of advanced imaging modalities underlying the importance of an integrated approach including 2D/3D transthoracic and transesophageal echocardiography, fluoroscopy, and computed tomography. In this scenario, it is critical to understand the strengths and weaknesses of each modality according to the suspected cause of PVD. In conclusion, for patients with suspected or known PVD, this stepwise imaging approach may lead to a simplified, more rapid, accurate and specific workflow and management.

Challenging Cases of Aortic Prosthesis Dysfunction, the Importance of Multimodality Imaging, a Case Series

ECG-gated multidetector computed tomography (MDCT) is a promising complementary technique for evaluation of cardiac native and prosthetic structures. MDCT is able to provide a broader coverage with faster scan acquisition times that yield higher spatial and temporal resolution for cardiac structures whose quality may be affected by artifacts on ultrasound. We report a case series about the most challenging complications occurring after prosthetic aortic valve implantation in four patients: pannus, paravalvular leak, prosthesis’ misfolding and subaortic membrane reformation. In all the cases, enhanced MDCT using a retrospective protocol provided accurate 3D morphoanatomic information about cardiac and extracardiac structures, improving and speeding up the correct diagnosis and treatment planning. Integrated imaging, in particular with MDCT, is now the present, and it will increasingly be the future in the assessment of cardiac structural pathology.

Tricuspid Valve Imaging and Right Ventricular Function Analysis Using Cardiac CT and MRI

Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMR) can reveal the detailed anatomy and function of the tricuspid valve and right ventricle (RV). Quantification of tricuspid regurgitation (TR) and analysis of RV function have prognostic implications. With the recently available transcatheter treatment options for diseases of the tricuspid valve, evaluation of the tricuspid valve using CT and CMR has become important in terms of patient selection and procedural guidance. Moreover, CT enables post-procedural investigation of the causes of valve dysfunction, such as pannus or thrombus. This review describes the anatomy of the tricuspid valve and CT and CMR imaging protocols for right heart evaluation, including RV function and TR analyses. We also demonstrate the pre-procedural planning for transcatheter treatment of TR and imaging of postoperative complications using CT.

EACVI recommendations on cardiovascular imaging for the detection of embolic sources: endorsed by the Canadian Society of Echocardiography

Cardioaortic embolism to the brain accounts for approximately 15-30% of ischaemic strokes and is often referred to as 'cardioembolic stroke'. One-quarter of patients have more than one cardiac source of embolism and 15% have significant cerebrovascular atherosclerosis. After a careful work-up, up to 30% of ischaemic strokes remain 'cryptogenic', recently redefined as 'embolic strokes of undetermined source'. The diagnosis of cardioembolic stroke remains difficult because a potential cardiac source of embolism does not establish the stroke mechanism. The role of cardiac imaging-transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), cardiac computed tomography (CT), and magnetic resonance imaging (MRI)-in the diagnosis of potential cardiac sources of embolism, and for therapeutic guidance, is reviewed in these recommendations. Contrast TTE/TOE is highly accurate for detecting left atrial appendage thrombosis in patients with atrial fibrillation, valvular and prosthesis vegetations and thrombosis, aortic arch atheroma, patent foramen ovale, atrial septal defect, and intracardiac tumours. Both CT and MRI are highly accurate for detecting cavity thrombosis, intracardiac tumours, and valvular prosthesis thrombosis. Thus, CT and cardiac magnetic resonance should be considered in addition to TTE and TOE in the detection of a cardiac source of embolism. We propose a diagnostic algorithm where vascular imaging and contrast TTE/TOE are considered the first-line tool in the search for a cardiac source of embolism. CT and MRI are considered as alternative and complementary tools, and their indications are described on a case-by-case approach.

Detection of Mechanical Prosthetic Valve Dysfunction

The long-term outcome of mechanical aortic and mitral prosthetic valve (A-PV, M-PV) dysfunction (PVD) remains a serious complication associated with high morbidity and mortality. We sought to evaluate the incremental diagnostic value of combined transthoracic echocardiography (TTE) and fluoroscopy (F) in patients with suspected PVD. A total of 354 patients (178 A-PV, 176 M-PV) were imaged by TTE and F within 5 days of hospital admission. PVD was confirmed by transesophageal echocardiography, computed tomography, effective thrombolysis, or surgical inspection. PVD was confirmed in 101 patients (57%) with M-PV and 99 (55%) with A-PV. Regardless of the mechanism of PVD, TTE shows good sensitivity and specificity, with accuracy of 80% for M-PV and 91% for A-PV. F shows high specificity, but low sensitivity with accuracy of 68% for M-PV and 78% for A-PV. The integration of TTE + F significantly improved accuracy both for M-PV (83%) and A-PV (96%). At ROC analysis, the combined model of TTE + F showed the highest area under the curve for the detection of PVD compared with TTE and F alone (p < 0.001). In conclusion, in patients with a clinical suspicion of PVD, the combined model of TTE + F offers incremental value over TTE or F alone. This multimodality imaging approach overcomes limitations of TTE or F alone and provides prompt identification of patients who may require further imaging assessment and/or closer follow up.

Hemodynamically significant prosthesis-patient mismatch can be predicted and is associated with early prosthetic valve dysfunction in aortic bioprosthesis

OBJECTIVES

To evaluate the accuracy of predicted prosthesis-patient mismatch (PPM) regarding actual PPM measured postoperatively. To assess the association between PPM and prosthetic valve dysfunction.

METHODS

Retrospective cohort study including adult patients after aortic valve replacement surgery with a biological prosthesis. Predicted PPM status was determined using mean reference effective orifice area indexed to total body surface (iEOA), without considering reference standard deviations. Postoperative PPM status was determined by measuring iEOA within the first 60 postoperative days. Prosthetic valve dysfunction was defined as thrombosis, pannus, valve degeneration, and/or disruption.

RESULTS

205 patients were enrolled between January 2003 and June 2017: predicted PPM was absent in 52 patients (25.4%), moderate in 137 patients (66.8%), and severe in 16 patients (7.8%). After surgery, the actual postoperative iEOA was measured: 53 (25.9%) did not have PPM, 73 had moderate PPM (35.6%), and 79 had severe PPM (38.5%). Predicted PPM identified the presence of hemodynamically significant actual postoperative PPM (OR = 2.56; 95%CI 1.30-5.05; P = .006), though not its degree of severity. Prosthetic valve dysfunction was more frequent among patients with hemodynamically significant PPM (53.9% vs. 11.3%; P < .001), compared to those without PPM. The association between PPM and prosthetic valve dysfunction was maintained after adjusting for gender, age, and ever-smoking (OR = 9.03; P < .001). The incidence of thrombosis or pannus was also nonsignificantly higher in patients with moderate or severe PPM.

CONCLUSIONS

Predicted PPM identifies the presence, possibly not the severity, of actual postoperative PPM. Moderate or severe PPM is associated with prosthetic valve dysfunction. Actual postoperative prosthesis-patient mismatch measured within 60 postoperative days showed a distinctive hemodynamic profile and presented a stronger association with prosthetic valve dysfunction than predicted prosthesis-patient mismatch. A. Echocardiographic follow-up in patients according to the actual postoperative PPM measured within 60 postoperative days. B. Prediction of prosthetic valve dysfunction based on preoperative predicted PPM or on actual postoperative PPM within 60 postoperative days. PPM: prosthesis-patient mismatch. OR: Odds ratio.

Characteristic localization patterns of thrombus on various brands of bileaflet mitral mechanical heart valves as assessed by three-dimensional transesophageal echocardiography and their relationship with thromboembolism

Three-dimensional transesophageal echocardiography (3D-TEE) provides detailed images of prosthetic valve thrombosis (PVT). However, data regarding PVT localization patterns based on 3D-TEE and their association with clinical findings among various bileaflet mitral prosthetic valve brands is lacking. The locations of thrombi were classified into 4 groups according to hinge and annulus involvement based on 3D-TEE: ring-like PVT involving entire mitral annulus (type-1), PVT involving peri-hinge(s) region and extends through some part of the annulus (type-2), PVT involving mitral annulus without involving hinge(s) region (type-3), and PVT involving only (peri)hinge(s) area (type-4). This study was conducted in 265 patients (male: 71, mean age: 46.3 ± 12.7 years) with mitral PVT, including 150 St Jude Medical (SJM), 65 Carbomedics, 29 Medtronic ATS open-pivot, and 21 Sorin bileaflet mechanical valves. There was a significant difference in most common PVT localization patterns between different prosthetic valves (type-1 for Carbomedics and Sorin; type-2 for SJM and type-3 for ATS valves; p < 0.001). Additionally, PVT involving only (peri)hinge region(s) (type-4) was mostly observed in patients with SJM valves (18%). (Peri)hinge(s) area involvement was observed in the majority of study patients (78.1%). In patients who presented with thromboembolism, the most common PVT localization pattern was type-1 (53%). Increased age, low international normalized ratio on admission, PVT with a mobile part > 2 mm, type-1 and type-4 PVT were associated with thromboembolic events. In conclusion, thrombus can be displayed in distinct locations in several types of bileaflet mechanical valves due to different design, hinge and pivot mechanisms, which can be complicated with thromboembolic events.

Fluorodeoxyglucose Applications in Cardiac PET: Viability, Inflammation, Infection, and Beyond

With its high temporal and spatial resolution and relatively low radiation exposure, positron emission tomography (PET) is increasingly being used in the management of cardiac patients, particularly those with inflammatory cardiomyopathies such as sarcoidosis. This review discusses the role of PET imaging in assessing myocardial viability, inflammatory cardiomyopathies, and endocarditis; describes the different protocols needed to acquire images for specific imaging tests; and examines imaging interpretation for each image dataset-including identification of the mismatch defect in viability imaging, which is associated with significant improvement in LV function after revascularization. We also review the role of fluorodeoxyglucose PET in cardiac sarcoidosis diagnosis, the complementary role of magnetic resonance imaging in inflammatory cardiomyopathy, and the emerging use of cardiac PET in prosthetic valve endocarditis.

Distinguishing aortic valve thrombus from Libman-Sacks endocarditis in antiphospholipid syndrome: imaging and management

Aortic valve (AV) thrombus, a rare complication of antiphospholipid syndrome (APLS), is important to distinguish from Libman-Sacks endocarditis because of its responsiveness to anticoagulation. This may be attributed to immunopathologic differences underpinning their development. We present the case of a 45-year-old woman with high-risk primary APLS who developed an AV mass and was taken for valvular repair surgery but found to have pure thrombus and normal valve leaflets. In such cases, a trial of conservative management with anticoagulation may be adequate. Echocardiography, computed tomography and MRI findings suggestive of thrombus without endocarditis are presented. A literature review of histopathologic, imaging and treatment implications of pure AV thrombus in the context of APLS is included.

Case report of successful low-dose, ultra-slow infusion thrombolysis of prosthetic mitral valve thrombosis in a high risk patient after redo-mitral valve replacement

Background

An increase in transvalvular pressure gradient of prosthetic valve should always raise suspicion for obstructive valve thrombosis. A multimodality diagnostic approach including transthoracic echocardiography, transoesophageal echocardiography (TOE), cinefluoroscopy, or computed tomography (CT) is necessary for a prompt diagnosis. The management of mechanical prosthetic valve thrombosis (PVT) is high risk in any therapeutic option taken. Emergency valve replacement is recommended for critically ill patients. Fibrinolysis is an alternative for patients with contraindication to surgery or if surgery is not immediately available.

Case summary

A 52-year-old woman presented with symptoms and signs of cardiac congestion. On laboratory, brain natriuretic peptide was elevated and international normalized ratio (INR) was in subtherapeutic range. She underwent a mitral valve replacement with mechanical prosthesis 7 months before, because of a significant residual regurgitation after repair on the same year. TOE revealed severe stenosis of the prosthesis with immobile anterior disc but there was no mass present. CT revealed a minor lesion at the hinge points of the prosthesis without involvement of the ring, suggestive for thrombus. The initial fruitless management with intravenous (i.v) heparin in high therapeutic range was followed by a successful 'low-dose, ultra-slow' fibrinolysis.

Discussion

CT may help differentiate thrombus vs. pannus. The acute onset of symptoms, inadequate anticoagulation, and restricted leaflet motion increased the suspicion for PVT. The current European guidelines propose normal dose fibrinolysis. We performed 'low-dose, ultra-slow' fibrinolysis due to lower bleeding risk with successful results. Low dose should be considered as alternative to normal dose fibrinolysis or urgent surgery.

Value of Computed Tomography Radiomic Features for Differentiation of Periprosthetic Mass in Patients With Suspected Prosthetic Valve Obstruction

Background:

We aimed to determine whether quantitative computed tomography radiomic features can aid in differentiating between the causes of prosthetic valve obstruction (PVO) in patients who had undergone prosthetic valve replacement.

Methods:

This retrospective study included 39 periprosthetic masses in 34 patients who underwent cardiac computed tomography scan from January 2014 to August 2017 and were clinically suspected as PVO. The cause of PVO was assessed by redo-surgery and follow-up imaging as standard reference, and classified as pannus, thrombus, or vegetation. Visual analysis was performed to assess the possible cause of PVO on axial and valve-dedicated views. Computed tomography radiomic analysis of periprosthetic masses was performed and radiomic features were extracted. The advantage of radiomic score compared with visual analysis for differentiation of pannus from other abnormalities was assessed.

Results:

Of 39 masses, there were 20 cases of pannus, 11 of thrombus, and 8 of vegetation on final diagnosis. The radiomic score was significantly higher in the pannus group compared with nonpannus group (mean, −0.156±0.422 versus −0.883±0.474; P <0.001). The area under the curve of radiomic score for diagnosis of pannus was 0.876 (95% CI, 0.731–0.960). Combination of radiomic score and visual analysis showed a better performance for the differentiation of pannus than visual analysis alone.

Conclusions:

Compared with visual analysis, computed tomography radiomic features may have added value for differentiating pannus from thrombus or vegetation in patients with suspected PVO.

A Novel Multiparametric Score for the Detection and Grading of Prosthetic Mitral Valve Obstruction in Cases With Different Disc Motion Abnormalities

Prosthetic mechanical valves are the elective choice in mitral valve (MV) replacement, because of their reliability and easiness of implantation. However, these prostheses can suffer from complications, the major one being prosthetic mitral valve thrombosis (PMVT). In these cases, transthoracic doppler echocardiogram (TDE) is the standard diagnostic workup for diagnosis of valve malfunction. The American Society of Echocardiography (ASE) indicates the possible TDE-derived indexes, which can help in identifying insurgence of MV replacement complications. Unfortunately, in some cases, it is not possible to detect PMVT based on these criteria. In these cases, we speak of Doppler silent thrombosis and only more accurate and invasive analyses, such as fluoroscopy, allow for a correct diagnosis. In this work, computational fluid dynamic models were implemented to simulate valve fluid dynamics in different clinical scenarios in order to improve the reliability of PMVT diagnosis based on TDE. In detail, seven mechanical valve configurations, associated to different potential thrombotic conditions (symmetric and asymmetric stenosis), were designed and tested using five pathologic transmitral velocity profile, extracted from real TDE images; to obtain the flow rate profiles, each TDE velocity profile was scaled to yield a mean flow rate (MFR) of 4, 5 and 6 L/min, respectively. As a result, 105 (7 × 5 × 3) synthetic cases, accounting for different velocity profiles, MFRs and valve configurations, were simulated. TDE-derived indexes were calculated according to the ASE guidelines that were extracted. Advanced statistical methods were applied to propose a new diagnostic algorithm for detecting PMVT. Our results showed that there isn't any significant difference between symmetric and asymmetric stenosis, probe location and flow rate waveform and confirmed that the single modality diagnostic is not able to predict thrombosis in a relevant number of cases, referable to mild and mild-severe stenosis cases. To overcome the problem, a novel multi-parametric discrete score based on the designed diagnostic algorithm was attained and tested; the percentage of stenosis (POS) was predicted with an accuracy rate of 90.5%. Even more interestingly, the error rate of 9.5% is related to four false positive cases corresponding to mild stenosis (POS = 15%) which were erroneously classified as mild-severe stenosis. No false negatives were obtained. Our results suggest that a reliable estimation must take into account the mean flow rate as well as the transmitral velocity profile in order to provide a correct diagnosis.

Prosthetic aortic valve thrombosis: To fibrinolyse or not to fibrinolyse? That is the question!

Prosthetic heart valve (PHV) dysfunction is a rare but serious complication whose optimal management may be challenging and requires a multidisciplinary approach. Treatment success ultimately depends on determining the underlying mechanism of valve dysfunction by echocardiography. However, being able to establish the main etiology is not always straightforward. We present a difficult case of obstructive PHV dysfunction and discuss clinical and echocardiographic parameters to help differentiate thrombus from pannus formation.

Use of Computational Fluid Dynamics to Analyze Blood Flow, Hemolysis and Sublethal Damage to Red Blood Cells in a Bileaflet Artificial Heart Valve

Artificial heart valves may expose blood to flow conditions that lead to unnaturally high stress and damage to blood cells as well as issues with thrombosis. The purpose of this research was to predict the trauma caused to red blood cells (RBCs), including hemolysis, from the stresses applied to them and their exposure time as determined by analysis of simulation results for blood flow through both a functioning and malfunctioning bileaflet artificial heart valve. The calculations provided the spatial distribution of the Kolmogorov length scales that were used to estimate the spatial and size distributions of the smallest turbulent flow eddies in the flow field. The number and surface area of these eddies in the blood were utilized to predict the amount of hemolysis experienced by RBCs. Results indicated that hemolysis levels are low while suggesting stresses at the leading edge of the leaflet may contribute to subhemolytic damage characterized by shortened circulatory lifetimes and reduced RBC deformability.

Computed Tomography of Cardiac Valves: Review

Valvular heart disease is a common clinical problem. Although echocardiography is the standard technique for the noninvasive evaluation of the valves, cardiac CT has evolved to become a useful tool in the evaluation of the cardiac structures as well. Importantly, CT allows for improved quantification of valvular calcification due to its superior spatial resolution. It may improve the detection of small valvular or perivalvular pathology or the characterization of valvular masses and vegetations. This review describes the assessment of normal and diseased heart valves by cardiac CT and discusses its strengths and weaknesses.

Novel imaging strategies for the detection of prosthetic heart valve obstruction and endocarditis

Prosthetic heart valve (PHV) dysfunction remains difficult to recognise correctly by two-dimensional (2D) transthoracic and transoesophageal echocardiography (TTE/TEE). ECG-triggered multidetector-row computed tomography (MDCT), 18-fluorine-fluorodesoxyglucose positron emission tomography including low-dose CT (FDG-PET) and three-dimensional transoesophageal echocardiography (3D-TEE) may have additional value. This paper reviews the role of these novel imaging tools in the field of PHV obstruction and endocarditis.

For acquired PHV obstruction, MDCT is of additional value in mechanical PHVs to differentiate pannus from thrombus as well as to dynamically study leaflet motion and opening/closing angles. For biological PHV obstruction, additional imaging is not beneficial as it does not change patient management. When performed on top of 2D-TTE/TEE, MDCT has additional value for the detection of both vegetations and pseudoaneurysms/abscesses in PHV endocarditis. FDG-PET has no complementary value for the detection of vegetations; however, it appears more sensitive in the early detection of pseudoaneurysms/abscesses. Furthermore, FDG-PET enables the detection of metastatic and primary extra-cardiac infections. Evidence for the additional value of 3D-TEE is scarce.

As clinical implications are major, clinicians should have a low threshold to perform additional MDCT in acquired mechanical PHV obstruction. For suspected PHV endocarditis, both FDG-PET and MDCT have complementary value.

Dysfunction of mechanical heart valve prosthesis: experience with surgical management in 48 patients

BACKGROUND

Dysfunction of mechanical heart valve prostheses is an unusual but potentially lethal complication after mechanical prosthetic valve replacement. We seek to report our experience with mechanical valve dysfunction regarding etiology, surgical techniques and early outcomes.

METHODS

Clinical data of 48 patients with mechanical valve dysfunction surgically treated between October 1996 and June 2011 were analyzed.

RESULTS

Mean age was 43.7±10.9 years and 34 were female (70.8%). The median interval from primary valve implantation to dysfunction was 44.5 months (range, 1 hour to 20 years). There were 21 emergent and 27 elective reoperations. The etiology was thrombosis in 19 cases (39.6%), pannus in 12 (25%), thrombosis and pannus in 11 (22.9%), improper disc orientation in 2 (4.1%), missing leaflet in 1 (2.1%), excessively long knot end in 1 (2.1%), endogenous factor in 1 (2.1%) and unidentified in 1 (2.1%). Surgical procedure was mechanical valve replacement in 37 cases (77.1%), bioprosthetic valve replacement in 7 (14.9%), disc rotation in 2 (4.2%) and excision of excessive knot end in 1 (2.1%). Early deaths occurred in 7 patients (14.6%), due to low cardiac output in 3 (6.3%), multi-organ failure in 2 (4.2%) and refractory ventricular fibrillation in 2 (4.2%). Complications occurred in 10 patients (20.8%).

CONCLUSIONS

Surgical management of mechanical valve dysfunction is associated with significant mortality and morbidity. Earlier identification and prompt reoperation are vital to achieving better clinical outcomes. The high incidence of thrombosis in this series highlights the need for adequate anticoagulation and regular follow-up after mechanical valve replacement.

Pannus-related prosthetic valve dysfunction. Case report

Pannus-related prosthetic valve dysfunction, a complication of mechanical prosthetic valve replacement, is rare, with a slowly progressive evolution, but it can be acute, severe, requiring surgical reintervention. We present the case of a patient with a mechanical single disc aortic prosthesis, with moderate prosthesis-patient mismatch, minor pannus found on previous ultrasound examinations, who presented to our service with angina pain with a duration of 1 hour, subsequently interpreted as non-ST segment elevation myocardial infarction (NSTEMI) syndrome. Coronarography showed normal epicardial coronary arteries, an ample movement of the prosthetic disc, without evidence of coronary thromboembolism, and Gated Single-Photon Emission Computerized Tomography (SPECT) with Technetium (Tc)-99m detected no perfusion defects. Transthoracic echocardiography (TTE) evidenced a dysfunctional prosthesis due to a subvalvular mass; transesophageal echocardiography (TOE) showed the interference of this mass, with a pannus appearance, with the closure of the prosthetic disc. Under conditions of repeated angina episodes, under anticoagulant treatment, surgery was performed, with the intraoperative confirmation of pannus and its removal. Postoperative evolution was favorable. This case reflects the diagnostic and therapeutic management problems of pannus-related prosthetic valve dysfunction.

Editorial to: Baseline MDCT findings after prosthetic heart valve implantation provide important complementary information to echocardiography for follow-up purposes by Suchá et al

Over the last years a growing number of prosthetic heart valve (PHV) implantation procedures have been performed in sequence with the aging of the population and improving surgical techniques. Currently, echocardiography is the most important tool in the follow-up and evaluation of complications associated with the PHV (pannus, thrombus, endocarditis). However, echocardiographic examination of PHV associated disease may be hampered by poor acoustic window or scatter artefacts caused by the PHV. PHV related disease such as endocarditis is related with a poor prognosis, especially when complications such as periannular abcess formation occurs. Early treatment of PHV associated disease improves prognosis. Therefore, an unmet clinical need for early detection of complications exists. In the evaluation of PHV (dys)function, multidetector-row computed tomography (MDCT) has shown to be of additive value. A necessity for MDCT to be implemented in daily practice is to be able to distinguish between normal and pathological features. Key Points • Early detection of PHV related complications improves prognosis • MDCT has additive value to echocardiography in the evaluation of PHV • RCTs for MDCT evaluation of PHV are required for clinical implementation.

Prosthetic mitral valve obstruction: role of real-time three-dimensional transesophageal echocardiography in diagnosis

Acute prosthetic valve thrombosis is a potentially serious complication with an incidence as high as 6% per patient-year for prostheses in the mitral position. Accurate diagnosis of the degree of obstruction and differentiation of pannus versus thrombus is critical in determination of the best mode of therapy. We discuss a case of a patient with multiple comorbidities who presented with mechanical mitral valve obstruction where both transthoracic and two-dimensional transesophageal echocardiography (TEE) were limited in making an accurate diagnosis regarding the mechanism of obstruction. Real-time 3D-TEE (RT-3DTEE) was critical in identifying a partial thrombus on the mechanical valve and guided the choice of thrombolysis as the most appropriate intervention, thus avoiding high-risk surgery in this patient with significant multiple comorbidities.

The year 2014 in the European Heart Journal--Cardiovascular Imaging: part II

The European Heart Journal-Cardiovascular Imaging, created in 2012, has become a reference for publishing multimodality cardiovascular imaging scientific and review papers. The impressive 2014 impact factor of 4.105 confirms the important position of our journal. In this part, we summarize the most important studies from the journal's third year, with specific emphasis on cardiomyopathies, congenital heart diseases, valvular heart diseases, and heart failure.

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.

A reoperation of thrombosed On-X valve detected by multidetector-row computed tomography

A 62-year-old female patient underwent mitral valve replacement with a 31/33-mm On-X valve for ischemic mitral valve regurgitation. Three months later, transthoracic echocardiography incidentally showed a blocked leaflet with 6 mmHg of mean pressure gradient and 2.4 cm(2) of mitral valve orifice area. Transesophageal echocardiography could not detect thrombus. Electrocardiographically gated multidetector-row computed tomography (MDCT) clearly demonstrated a blocked leaflet in the close position and thrombus (2 cm in length, 0.4 cm(2) in area) attached onto the atrial aspect of the leaflet. These findings observed by MDCT were confirmed at reoperation. MDCT was useful diagnostic method for visualizing prosthetic valve thrombosis.