“Bridging” and Mechanical Heart Valves

The development of heparin-induced thrombocytopenia (HIT) is an antibody-mediated clinicopathologic syndrome. The resultant thrombocytopenia and thrombosis can be severe and life-threatening. Fondaparinux is a parenteral factor Xa inhibitor used for venous thromboembolism prevention and treatment. Fondaparinux has minimal affinity for platelet factor 4, making it an alternative agent to unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) and a plausible consideration for patients with a history of HIT. The use of fondaparinux in patients with mechanical heart valve replacement and a history of HIT has never been discussed in the literature. We report on the case of a patient with a mechanical aortic heart valve replacement and a history of HIT who was successfully bridged postoperatively with fondaparinux. While there is currently no literature to support the use of fondaparinux in patients with mechanical heart valves, this drug may offer an option for management of such patients who cannot use heparin products. However, further clinical investigations are warranted to confirm both the safety and efficacy of this agent in the mechanical heart valve population.

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

Biological versus mechanical heart valve prosthesis during pregnancy in women with congenital heart disease

ObjectiveTo assess different bridging anticoagulation therapies early after mechanical heart valve replacement (MHVR) in Chinese patients.MethodsWe performed a prospective, single-center, observational cohort study of 305 patients who underwent elective MHVR with different bridging anticoagulation regimens. Patients enrolled in the study were divided into three bridging therapy groups: the unfractionated heparin (UFH) group (n = 109), the low-molecular-weight heparin (LMWH) group (n = 97), and the UFH with sequential LMWH (UFH-LMWH) group (n = 99). All patients were followed for 4 weeks.ResultsTwo patients experienced thromboembolic stroke events in the UFH group. The LMWH group was associated with an increase in the incidence of bleeding events compared with the UFH group (10.3% VS 2.8%; P = 0.03). With a comparison of LMWH and UFH group in secondary endpoints, the statistical test for significance indicated a trend of reduced ICU length of stay (P = 0.08), postoperative length of stay (P = 0.08) and time of achieving target INR (P = 0.06). The creatinine level (odds ratio = 1.03; 95% confidence interval = 1.01 to 1.05; P = 0.02) and hypertension (odds ratio = 3.72; 95% confidence interval = 1.35 to 10.28; P = 0.01) were risk factors for bleeding events.ConclusionFor Chinese patients, the LMWH bridging anticoagulation presents the increased the incidence of bleeding events, but enables patients to benefit from achieving an early anticoagulation effect. Close follow-up and personalized management are required in patients with thromboembolic and bleeding risk factors.Trial registrationChinese Clinical Trial Registry ChiCTR1800019841. Registered 2 December 2018 retrospectively.

Antithrombotic therapy in patients with valvular heart disease and prosthetic heart valves

Patients with mechanical heart valves require life-long anticoagulation. We report here the first large and comparative series of consecutive patients anticoagulated with low molecular weight heparin (LMWH) after mechanical heart valve replacement. In this comparative, nonrandomized study, 208 consecutive patients who underwent a single or double heart valve replacement with mechanical prostheses were anticoagulated subcutaneously with unfractionated heparin (UH) in the first period (n=106) and LMWH in the second phase (n=102) of the study. Baseline characteristics were similar in the 2 groups. The mean durations of UH and LMWH treatments were 13.6+/-0.5 and 14.1+/-0.6 days, respectively (not significant). On the second day of treatment, 87% of patients treated with LMWH had an anti-Xa activity within the range of efficacy (0.5 to 1 IU/mL), but only 9% of UH-treated patients had an activated partial-thromboplastin time value within the therapeutic range (1.5 to 2.5 times control, P<0.0001 between the 2 groups). On the last day of prescription, all LMWH-treated patients had anti-Xa activity above 0.5 IU/mL, but 19% were above 1 IU/mL. In the UH group, 27% of patients had an activated partial-thromboplastin time above 1.5 times control, but 62% were overanticoagulated. Two major bleedings occurred in each group, and one stroke occurred in the UH group. In this first comparative study, anticoagulation with LMWHs after mechanical heart valve replacement appears feasible, provides adequate biological anticoagulation, and compares favorably with UH anticoagulation. Randomized studies are now needed to further evaluate this new therapeutic approach.

A substantial body of published, peer-reviewed, trial and cohort study-based evidence, institutional data sets and expert clinical experience/opinion supports the safe and effective use of enoxaparin for anticoagulation management of non-pregnant patients with prosthetic mechanical heart valves. A comparable body of data and trial results exists, also supported by a significant and authoritative base of expert opinion, for enoxaparin-based VTE prevention and treatment of at-risk pregnant patients who do not have mechanical heart valves. In pregnant women with prosthetic mechanical heart valves, no recommendations on the use of LMWHs can be made until the availability of more data (Lovenox Injection (package insert). Available at www.aventis-us.com/PIs/lovenox. Accessed July 30, 2003. Aventis Pharmaceuticals 2003).

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

Background Prosthetic heart valve thrombosis (PHVT) represents a dangerous postoperative complication following prosthetic heart valve replacement. Incidence varies according to different data from 0.5–4 % per year following mitral or aortic valve replacement in spite of adequate oral anticoagulation with coumarins. Case report We are presenting a case of prosthetic mitral valve thrombosis as a result of 6-month lowmolecular-weight heparin (LMWH) (nadroparine) treatment failure. Our patient presented with clinical picture of massive and recurrent bilateral pleural effusions and sub sequent development of acute left-sided heart failure. Diagnosis was made with transesophageal ultrasound examination. The patient underwent surgical thrombectomy and recovered completely. He died a month later because of pneumonia with septic complications and multiorgan failure. Conclusions Our case raises suspicion that the use of LMWHs as an alternative anticoagulant for long-term antithrombotic prophylaxis in patients with prosthetic heart valves carries an increased risk of PHVT. There is a lack of larger randomised trials comparing the safety of LMWH and coumarin anticoagulation in patients with prosthetic heart valves.

Background and Purpose—It has been shown previously that cerebral microemboli may occur frequently in patients with a normal mechanical heart valve (MHV) without prior history of stroke. Some arguments strongly suggest that these microemboli have a gaseous origin. In other circumstances such as extracorporeal circulation or decompression in divers, it has been demonstrated that cerebral microbubbles could lead to some deterioration in cognitive functions. Therefore, we have studied attention and memory, which are among the most impaired cognitive functions as demonstrated in previous studies, in patients with an MHV. Methods—Three groups of 12 volunteers each were composed of patients with an MHV and embolic signals in the cerebral circulation (group 1), patients with biological prostheses (group 2), and healthy subjects (group 3). Groups were carefully matched for age and verbal intellectual abilities. For each group, a transcranial Doppler examination was performed and a set of cognitive tests assessing...

Anticoagulation therapy with combined low dose aspirin and warfarin following mechanical heart valve replacement

BackgroundThe optimal choice of the valve prosthesis in mitral valve replacement (MVR) for infective endocarditis (IE) is controversial and challenging, particularly for younger patients.HypothesisThe postoperative outcomes of mechanical and biological MVR in IE patients aged 50 to 69 years are different.MethodsAll IE patients aged 50 to 69 years with primary MVR in Hubei province hospitals from 2002 to 2018 were retrospectively reviewed. The median duration of follow‐up was 8.7 years (IQR, 6.8‐10.9 years). Propensity score matching (1:3 ratio) was used to yield 492 patients with comparable baseline features between bioprostheses and mechanical prosthetic valve groups. Outcomes were postoperative mid‐ to long‐ term survival, mitral valve reoperation, prosthetic valve endocarditis (PVE), stroke, and major bleeding events.ResultsFifteen‐year survival after MVR was 80.6% in the mechanical valve group and 69.3% in the bioprostheses group (HR 0.545, P = .040). The cumulative incidence of mitral valve reoperation was 8.8% with mechanical valves and 21.4% with bioprostheses (HR 0.260, P = .002). The cumulative incidence of PVE was 5.6% with mechanical valves and 7.2% with bioprostheses (HR 0.629, P = .435). The cumulative incidence of stroke was 12.9% with mechanical valves and 10.5% with bioprostheses (HR 1.217, P = .647). The cumulative incidence of major bleeding was 12.0% with mechanical valves and 6.75% with bioprostheses (HR 1.579, P = .268).ConclusionsMechanical valve prostheses were associated with better survival, lower rates of reoperation compared with bioprostheses within 15 years after MVR in IE patients aged 50 to 69. These findings suggest mechanical valve prostheses may be a more reasonable alternative to bioprostheses in this patient group.

Mechanical prosthetic heart valves: Quality of anticoagulation and thromboembolic risk. The observational multicenter PLECTRUM study

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.

Invited commentary