Multimodality imaging for prosthetic valves evaluation: Current understanding and future directions

Mechanical heart valves require anticoagulation to prevent valve-associated thrombosis and thromboembolic stroke. Oral vitamin K antagonists such as warfarin are prescribed universally; however, oral agents do not act immediately and usually require at least 5 days to achieve a therapeutic effect. Article p 564 Measurement of the prothrombin time, which is standardized by reporting the result as the international normalized ratio (INR), assesses the anticoagulant effect of warfarin. For most mechanical heart valves, the target INR ranges between 2.0 and 3.5. In the postoperative cardiac surgical setting, patients are usually started on low doses of warfarin because they tend to have impaired hepatic metabolism and suboptimal nutritional status. Even with low initial doses of warfarin, mechanical heart valve replacement patients are susceptible to excessively high INRs.1 This known exaggerated initial response to warfarin after heart valve replacement can lead to the habitual prescription of such low warfarin doses that warfarin as monotherapy may not achieve a stable and therapeutic INR for weeks after its initiation. To minimize the delay in achieving therapeutic anticoagulation, a “bridging” anticoagulant is prescribed. The “bridge” is administered parenterally, thereby providing an immediate anticoagulant effect. Traditionally, the “bridging” agent has been unfractionated heparin (UFH). More recently, physicians tend to select low-molecular-weight heparin (LMWH), even though few studies exist to validate the efficacy and safety of either LMWH or UFH in this setting. The rationale for shunning UFH has been to avoid the known perils and inconveniences of its use as a continuous peripheral intravenous infusion. UFH is rarely administered in an immediately therapeutic dose because of fear of precipitating bleeding complications. Especially in postoperative mechanical valve replacement patients, there is reluctance to follow the high dosing requirements for initial bolus and infusion regimens published in standardized nomograms. Instead, UFH is usually started in cautious small …

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Intravascular Hemolysis and Acute Renal Failure After Mitral and Aortic Valve Repair

The need for mechanical analyses in heart valve prosthesis development was recognized in the mid-1900s as Dr. Hufnagel began the development and introduction of prosthetic heart valves [1]. It was recognized that the “ball valve” designs diverted the blood flow from a central flow to a flow around the balls. This can cause damage to the blood cells and also may cause the heart to work harder [2]. Tilting disc prosthetic heart valves helped restore the desirable central flow, reducing the damage to blood cells. However one design (the Bjork-Shiley valve) developed a reliability issue which resulted in multiple fatal events; this reliability issue was related to the weld used for the struts, and the valve was removed from the market by 1986. Later some structural finite element analyses were completed in attempts to quantify the stresses related to the failures and to develop differing methods of failure detection [3, 4]. The methods for failure detection involved acoustic and harmonic analyses. Experimentally, the resonant frequencies for intact and fractured struts were measured and were found to be significantly different. A finite element modal analysis of the Bjork-Shiley valve was created [5] and the responses compared favorably to the experimental studies [6, 7]. Chondros (2010) improved on these acoustic methods, and suggested a method of monitoring fatigue crack propagation in the valve strut [7]. Well-validated methods like this would be useful in identification of broken valve struts prior to any clinical symptoms.

Pregnancies in women with prosthetic heart valves have historically been associated with an increased incidence of adverse outcomes for both the mother and fetus. These outcomes include miscarriage, thromboembolism, postpartum hemorrhage (PPH), and prenatal complications such as preterm birth (PTB), small for gestational age (SGA), and congenital anomalies. The design of prosthetic heart valves has continued to improve, with highly thrombogenic ball valves and large-style valves being replaced by newer bioprosthetic types. These advancements have significantly reduced the need for anticoagulant regimens during pregnancy, leading to better outcomes. Consequently, alongside improvements in obstetric and medical care, the prognosis for pregnant women with mechanical heart valves has markedly improved. However, this patient group still faces unique challenges due to the necessity of anticoagulation therapy to prevent valve thrombosis while ensuring the safety of both mother and fetus. Introduction: Pregnancy in women with heart disease continues to be a clinical challenge due to the associated significant morbidity and pregnant women with mechanical heart valves has an increased risk of adverse outcome both maternal and fetal [1, 2]. However, the biomedical advancement in the heart valves raises the question if there is difference between the maternal and fetal outcome in the mechanical valves used: Prosthetic and Bioprosthetic heart valves. Therefore, we conducted a retrospective study to identify the maternal and fetal adverse outcome in women with mechanical heart valves and to compare the incidence of the adverse outcome between Prosthetic and Bioprosthetic heart valves pregnant women. Materials and Methods: A retrospective study was conducted in the Obstetrics and Gynecology Department at Royal Hospital, Oman. All pregnant women with mechanical heart valves who were followed and delivered at Royal Hospital over the past 10 years (January 2010 to December 2020) were included. The collected data included maternal, pregnancy, and fetal details based on the literature review. Data was collected from the Alshifa Electronic Medical Record System, and statistical analysis was performed using SPSS software. Fisher Exact test was used for measuring the statistically significant relationship between Prosthetic, Bioprosthetic and the outcome. Result: A total of 301 patients were included. 61 patients (20.3%) were Primi-gravida whereas (79.7 %) were women with multiple pregnancy. Bioprosthetic valve found in 199 patient (66.1%) of the included patients. (82.4%) 248 patient were with single valve replacement. The most common of replacement valve replacement Rheumatic heart disease by (59.5%). Since majority of the patient were with Bioprosthetic valve, (65.8%) were not on anticoagulation therapy. Regarding maternal outcome: Mortality rate was (2%), whereas other complication including valve thrombosis, PIH were (3%), Miscarriage was found in 21.3% of the cases and was seen more with patient who were on warfarin. The rate of cesarean section was (23%) comparing to spontaneous vaginal delivery (77%). Termination was indicated on 5 patient (1.7%) with variable reasons for terminations including maternal and fetal indications. For the Fetal outcome: 193 (64.1%) term, 15 (5%) preterm, out of which 43 (14.3%) required NICU admission. Perinatal mortality was (1.3%). 53 (17.6%) were Low Birth weight newborn. And 3 cases (1%) with fetal anomalies. Conclusions: Women with heart valve experienced highly risk of adverse outcome then expected in general obstetric population. Women with Bioprosthetic have less adverse outcome. Balancing the risks of thrombosis and bleeding complications during pregnancy is critical for optimal maternal and fetal outcomes. Multidisciplinary pre-pregnancy counselling is important.

ObjectiveThis work describes the experimental validation of a cardiac simulator forthree heart rates (60, 80 and 100 beats per minute), under physiologicalconditions, as a suitable environment for prosthetic heart valves testing inthe mitral or aortic position.MethodsIn the experiment, an aortic bileaflet mechanical valve and a mitralbioprosthesis were employed in the left ventricular model. A test fluid of47.6% by volume of glycerin solution in water at 36.5ºC was used as bloodanalogue fluid. A supervisory control and data acquisition systemimplemented previously in LabVIEW was applied to induce the ventricularoperation and to acquire the ventricular signals. The parameters of the leftventricular model operation were based on in vivo and invitro data. The waves of ventricular and systemic pressures, aortic flow,stroke volume, among others, were acquired while manual adjustments in thearterial impedance model were also established.ResultsThe acquired waves showed good results concerning some invivo data and requirements from the ISO 5840 standard.ConclusionThe experimental validation was performed, allowing, in future studies,characterizing the hydrodynamic performance of prosthetic heart valves.

A case of biventricular thrombi in a patient with dilated cardiomyopathy: Utility of multimodality imaging for diagnosis and management of treatment strategy

Echocardiography- and cardiovascular magnetic resonance (CMR)-based studies have revealed a wide range of phenotypic manifestations in hypertrophic cardiomyopathy (HCM) apart from hypertrophy. This study sought to comprehensively describe a number of structural abnormalities in HCM beyond hypertrophy, by multimodality imaging. A total of 100 HCM patients were prospectively enrolled, undergoing standard and contrast echocardiography, and CMR. Morphological characteristics involving mitral valve leaflets (MVL), subvalvular apparatus, and left ventricular cavity and wall were investigated. Seventy healthy volunteers served as control population. As assessed by echo, MVLs were longer in HCM patients than in controls (anterior method 1: 24[22,28] vs 19[18,20] mm, P<0.01; anterior method 2: 27[24, 29] vs 21[19, 23] mm, P<0.01; posterior: 15[12,19] vs 14[13,15] mm, P<0.01). Abnormal chordal attachment to anterior MVL, anterior papillary muscle displacement, and accessory apical-basal muscle bundle were present in 42 (42%), 61 (61%), and 35 (35%) patients, respectively (P values vs controls <0.01); direct papillary muscle insertion into MVL and hypertrabeculation were found in two and five patients, respectively. Contrast echocardiography (n=94) detected myocardial crypts in 15 patients (16%). Overall, 83% of HCM subjects had at least one of these phenotypic manifestations. Echocardiography and CMR agreement for MVL length was poor, while for structural characteristics was moderate to substantial (Cohen's Kappa: 0.53-1.00). Except for posterior MVL length and hypertrabeculation, the phenotypic characteristics studied had acceptable reproducibility by echocardiography and CMR. Structural abnormalities in HCM beyond hypertrophy are significantly common. Multimodality imaging approach to these HCM facets by echocardiography and CMR is feasible and desirable.

Multimodality imaging in bicuspid aortic valve

Thrombotic and thromboembolic events are important causes of mortality and morbidity in patients with prosthetic heart valve. The aim of this study is to evaluate the factors that may contribute to prosthetic heart valve thrombosis. This was a cross-sectional study in Rajaie Heart Center on patients with prosthetic heart valve malfunction, within a year. According to the echocardiographic and fluoroscopic findings, the patients were divided into two groups (thrombosis and non-thrombosis groups). The patients' demographic, clinical and laboratory data were recorded and analyzed with SPSS software. A total of 142 patients participated in this study. Ninety-four patients (66.2%) were diagnosed with thrombosis. There was a significant relationship between thrombosis and inadequate anti-coagulation (international normalized rati [INR] <2.5) (odds ratio [OR]: 4.15, 95% CI: 1.98-9.87, P = 0.003), history of infection (OR: 12.81, 95% CI: 3.52-19.02, P<0.001), prothrombin time (PT) check interval (OR: 2.38, 95% CI: 1.63-8.47, P = 0.019), atrial fibrillation (AF) rhythm (OR: 3.96, 95% CI: 1.75-8.09, P = 0.019), and plasma fibrinogen level (OR: 6.90, 95% CI: 2.58-14.69). Based on this study, inadequate anti-coagulation, AF rhythm, recent infection and plasma fibrinogen level were the factors most contributing to prosthetic valve thrombosis. As there were many cases of thrombosis in patients with history of infection, this factor can be considered for risk assessment in prosthetic valve.

ACC/AATS/AHA/ASE/ASNC/HRS/SCAI/SCCT/SCMR/STS 2017 Appropriate Use Criteria for Multimodality Imaging in Valvular Heart Disease: A Report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic

ACC/AATS/AHA/ASE/ASNC/HRS/SCAI/SCCT/SCMR/STS 2017 Appropriate Use Criteria for Multimodality Imaging in Valvular Heart Disease: A Report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic

Commentary: Greater risk of infective endocarditis after biologic valve replacement: A word of caution before expanding the indications to younger patients

Role of Multimodal Cardiac Imaging in Low-Flow, Low-Gradient Aortic Stenosis

In the recent years, there has been significant transformation in the management of valvular heart disease (VHD), as a result of new minimally invasive technologies, such as the transcatheter aortic valve implantation (TAVI). Conventionally, mechanical heart valves require anticoagulation with warfarin to prevent thrombogenic events. Lately, there has been an uptrend in the usage of direct-acting oral anticoagulants (DOACs) in both mechanical and bioprosthetic heart valves. In clinical practice, there has shown to be notable heterogeneity in the antithrombotic regimen for patients. Recommendations from clinical guidelines and emerging data on DOAC use in these settings will be critically reviewed here. Future large, randomized-controlled trials are warranted to delineate the role of DOACs in patients receiving a bioprosthetic valve/TAVI or mechanical heart valve, with and without a baseline indication for anticoagulation or antiplatelets. Until clinical trial data from well-designed studies are available, providers must remain vigilant about DOAC use in patients with VHD, especially in patients with a bioprosthetic or mechanical heart valve.