Long-term results of valve replacement with the St. Jude Medical prosthesis

Between a rock and a hard place: resumption of oral anticoagulant therapy after intracranial hemorrhage

Intracranial hemorrhage (ICH) is the most feared and lethal complication of oral anticoagulant (OAC) therapy. Resumption of OAC after ICH has long posed a challenge for clinicians, complicated by the expanding range of anticoagulant agents available in modern clinical practice, including direct OACs and, more recently, factor XI and XII inhibitors. A review of the current literature found support for resuming OAC in the majority of patients after ICH based on pooled retrospective data showing that resumption is associated with a lower risk of mortality and thromboembolism without a significantly increased risk of recurrent hemorrhage. The optimal time to resume OAC is less clear; however, the available evidence suggests that the composite risk of both recurrent hemorrhage and thromboembolism is likely minimized, somewhere between 4 and 6 weeks, after ICH in most patients. Specific considerations to guide the optimal resumption time in the individual patient include ICH location, mechanism, and anticoagulant class. Patients with mechanical heart valves and intracerebral malignancy represent high-risk groups who require more nuanced decision making. Here, we appraise the literature with the aim of providing a practical guide for clinicians while also discussing priorities for future investigation.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Outcome of Patients With Both Moderate Aortic Stenosis and Moderate Mitral Stenosis

Aims

This study aimed to investigate the symptoms and prognosis of patients with both moderate aortic stenosis (AS) and mitral stenosis (MS).

Methods and Results

We studied 82 patients with moderate AS and MS diagnosed via transthoracic echocardiography. The patients had a mean age of 79 ± 13 years and 95% of patients had degenerative MS. Out of 82 patients, 34 (41%) had heart failure (HF) symptoms (New York Heart Association class ≥ Ⅱ) or a history of HF admission. Left ventricular ejection fraction, stroke volume index, atrial fibrillation, and right ventricular systolic pressure were independent determinants of HF symptoms. The median follow-up duration was 3.2 (interquartile range, 1.0-4.9) years and clinical events occurred in 48 (59%) patients, including death in 11 (13%) patients, aortic or mitral valve interventions in 22 (27%) patients, and HF hospitalization in 15 (18%) patients. The 5-year survival free of the combined endpoint of aortic or mitral valve interventions, HF hospitalization, or death was 19%. A multivariate predictor of clinical events was HF symptoms (hazard ratio [HR], 2.32; 95% confidence interval [CI], 1.30-4.14; p = 0.0045). Kaplan-Meier survival at 5 years was 61% without intervention and HF symptoms were not associated with mortality.

Conclusions

Among patients with both moderate AS and MS, left ventricular ejection fraction, stroke volume index, atrial fibrillation, and right ventricular systolic pressure were strong determinants of HF symptoms. HF symptoms were independently predictive of clinical events.

Periprocedural Anticoagulation

Management of patients taking anticoagulants around the time of a procedure is a common and complex clinical scenario. Providing evidence-based care requires estimation of risk for thrombosis and bleeding, knowledge of commonly used medications, multidisciplinary communication and collaboration, and patient engagement and education. This review provides a standardized, evidence-based approach to periprocedural management of anticoagulation, based on current evidence and expert clinical guidelines.

PROSE: Prospective Randomized Trial of the On-X Mechanical Prosthesis and the St Jude Medical Mechanical Prosthesis Evaluation: Part 2: Study results-prostheses, positions, and economic development

Objectives

The Prospective Randomized On-X Mechanical Prosthesis Versus St Jude Medical Mechanical Prosthesis Evaluation (PROSE) trial purpose was to investigate whether a current-generation mechanical prosthesis (On-X; On-X Life Technologies/Artivion Inc) reduced the incidence of thromboembolic-related complications compared with a previous-generation mechanical prosthesis (St Jude Medical Mechanical Prosthesis; Abbott/St Jude Medical). This second report documents the valve-related complications by individual prostheses and by Western and Developing populations.

Methods

The PROSE trial study was conducted in 28 worldwide centers and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The study protocol, and analyses of 10 demographic variables and 24 risk factors were published in detail in 2021.

Results

The total patient population (N = 855) included patients receiving an On-X valve (n = 462) and a St Jude Medical valve (n = 393). The overall freedom evaluation showed no differences at 5 years between the prostheses for thromboembolism or for valve thrombosis. There were also no differences in mortality. There were several differences between Developing and Western populations. The freedom relations at 5 years for mortality favored Western over Developing populations. Valve thrombosis was differentiated by position and site: aortic < mitral (P = .007) and Western < Developing (P = .005). In the mitral position there were no cases in Western populations, whereas there were 8 in Developing populations (P = .217).

Conclusions

The On-X valve and St Jude Medical valve performed equally well in the study with no differences found. The only differentiation occurred with valve thrombosis in the mitral position more than the aortic position and occurring in Developing more than Western populations. The occurrence of valve thrombosis was also related to a younger population possibly due to anticoagulation compliance based on record review.

Comparison between surgery and fibrinolytic therapy in prosthetic valve thrombosis: A systematic review and meta-analysis

BACKGROUND

Prosthetic valve thrombosis (PVT) is a rare but life-threatening complication. Surgery and fibrinolytic therapy (FT) are the two main treatment options for PVT. The choice between surgery and FT has always been a matter of debate. Previous studies have shown that although the mortality rate is higher in surgery, complications are less frequent than in FT. We aimed to perform a systematic review and meta-analysis to compare the results of surgery and FT in PVT.

METHODS

A systematic review of the literature was performed through Medline, Embase, Scopus, and Web of Science, encompassing all studies comparing surgery and FT in PVT. The rate of each complication and risk ratio (RR) of complications in surgery and FT were assessed using random-effects models.

RESULTS

Fifteen studies with 1235 patients were included in the meta-analysis. The pooled risk of the mortality was not significantly different between FT and surgery in patients with PVT (pooled RR = 0.78, 95% confidence interval [CI]: 0.38-1.60, I² = 61.4%). The pooled risks of thromboembolic events (pooled RR = 4.70, 95% CI: 1.83-12.07, I² = 49.6%) and major bleeding (pooled RR = 2.45, 95% CI: 1.09-5.50, I² = 41.1%) and PVT recurrence (pooled RR = 2.06 95% CI: 1.29-3.27, I² = 0.0%) were significantly higher in patients who received FT.

CONCLUSION

Surgery may be safer and with fewer complications than FT for PVT treatment. However, randomized clinical trials are needed to determine the proper treatment for PVT.

Cardiac Operations after Transcatheter Aortic Valve Replacement

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is now frequently performed for severe aortic stenosis. Data regarding cardiac operations after TAVR are limited, however. Therefore, we investigated patient characteristics, operative timing and indications, and outcomes of these operations in a single-center experience.

METHODS

From 1/2012-7/2020, 59 patients (median age 70) underwent cardiac operations after TAVR, 38 (64%) of the latter performed outside our center. Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) was calculated at time of prior TAVRs and at applicable index cardiac operations.

RESULTS

From 2012-2018, there were fewer than 10 operations after TAVR, but 18 in 2019. Interval between prior TAVR and cardiac surgery decreased exponentially from 7 to less than 1 year over the experience. In applicable cases (n=19; 32%), median STS-PROM was 5.5% (15^th-85th percentiles, 3.1%-25%); 40 (68%) were complex operations with no calculable STS-PROM. The TAVR valve was explanted in 46 (78%); 5 were isolated surgical AVRs. TAVR valve stenosis/regurgitation (n=34; 58%) was the leading indication, followed by paravalvular leak (14; 24%) and endocarditis (n=10/17%). When the TAVR valve was not explanted, mitral regurgitation was the leading indication for operation. Operative mortality was 5 (8.5%), postoperative stroke 2 (3.4%), and postoperative dialysis 6 (10%).

CONCLUSIONS

Cardiac operations after TAVR are increasing and interval between TAVR and operation decreasing. Most cardiac operations are complex, high-risk reoperations and isolated AVR rare. These findings should be considered when TAVR is selected for low-intermediate risk patients, particularly with multiple cardiac pathologies not addressed by TAVR.

Impact of Aortic Valve Replacement for Aortic Stenosis on Coexisting Mitral Stenosis

PURPOSE

The course of coexisting mitral valve stenosis is not clear after aortic valve replacement (AVR) for aortic stenosis (AS). We investigated the effect of AVR for AS on coexisting mitral stenosis (MS).

METHODS

Between January 2002 and December 2019, 1338 consecutive patients underwent surgical AVR at Shiga University of Medical Science. Of them, 34 patients with moderate MS (mitral valve area [MVA]: 1.5-2.0 cm²) were included in the present study. We evaluated the postoperative clinical outcomes in these patients.

RESULTS

Mean MVA in our cohort significantly increased 1 week after operation compared with preoperative values, and the change was maintained for 5 years after surgery. Follow-up was completed in 94.1% (32/34) patients, and mean follow-up duration was 4.0 ± 3.0 years. No patients underwent mitral surgery for remaining MS after AVR during postoperative follow-up.

CONCLUSION

AVR for AS resulted in increased MVA in patients with MS, and the change was maintained during follow-up.

A Rare Case of Partial Aortic Mechanical Valve Thrombosis With Intact Mitral Mechanical Valve Presenting With ST-Elevation Myocardial Infarction Patients

The incidence of mechanical valve thrombosis (MVT) is around 0.4 per 100 patient-years. Mitral valve thrombosis has a higher incidence than aortic valve thrombosis with a nearly 5-fold increase. Various factors contribute to MVT. The most common cause of valve thrombosis is poor adherence/disruption of anticoagulation therapy. Low cardiac output is known to increase the risk of prosthetic valve thrombosis. Other factors such as diabetes, hypertension, and other patient comorbidities might also play a role. Decreased flow promotes hypercoagulability. Lower pressure in the left atrium (and higher velocities in the left ventricle) can partially contribute to the higher incidence of mitral MVT versus aortic MVT. The presenting symptoms usually depend on the severity of the valve thrombosis; nonobstructive valve thrombosis patients have progressive dyspnea, signs of heart failure, and systemic embolization with strokes being the most common complication. In this article, we present a case of a middle-aged woman with a history of mitral and aortic mechanical prosthesis who presented with an ST-segment elevation myocardial infarction and pulmonary edema due to mechanical aortic valve prosthesis thrombosis. She had an isolated mechanical aortic valve prosthesis thrombosis with intact mitral valve, which, to the best of our knowledge, has not yet been described. We performed a literature review by searching PubMed and Embase using the keywords “mechanical valve,” “thrombosis,” “aortic,” and “mitral,” our search did not show similar cases.

Impact of Mitral Stenosis on Survival in Patients Undergoing Isolated Transcatheter Aortic Valve Implantation

This study was performed to investigate the prevalence and impact on survival of baseline mitral stenosis (MS) in patients who underwent transcatheter aortic valve implantation (TAVI) due to the presence of severe symptomatic aortic stenosis. This retrospective study included 928 consecutive patients with severe, symptomatic aortic stenosis who underwent TAVI in 2 institutions, from January 2012 to August 2016. Mean follow-up was 40.8 ± 13.9 months. Based on the mean mitral gradient (MMG) at baseline, 3 groups were identified: MMG <5 mm Hg (n = 737, 81.7%); MMG ≥5 and <10 mm Hg (n = 147, 16.3%); MMG ≥10 mm Hg (n = 17, 1.9%). These latter were more frequently women, with a smaller body surface area, a higher prevalence of atrial fibrillation, chronic obstructive pulmonary disease, and previous history of coronary-artery bypass graft/percutaneous coronary intervention. At baseline, patients with MMG ≥10 mm Hg compared with ≥5 and <10 mm Hg and <5 mm Hg patients had a lower mitral valve area (2.4 ± 0.94 vs 2.1 ± 0.86 vs 1.5 ± 0.44 cm²), a lower prevalence of MR ≥2+ (5.9% vs 28.6% and 15.6%, p <0.0001), a higher prevalence of severe mitral annular calcium (70.6% vs 45.6% and 13.0%, p <0.0001) and a higher systolic pulmonary arterial pressure (50.6 ± 12.1 vs 47.2 ± 14.5 and 41.6 ± 14.4, p <0.0001). Despite the low prevalence of MMG ≥10 mm Hg, these patients had higher 5-year mortality compared with the other groups (adjusted hazard ratio 2.91, 95% confidence interval 1.17 to 7.20, p = 0.02). In conclusion, severe calcific MS is uncommon in patients who underwent TAVI. Its presence is associated with higher long-term mortality whereas moderate MS is not.

Postoperative Anticoagulation After Neurologic Surgery

Management of anticoagulation and antiplatelet medications after neurosurgery can be complex, especially given that these patients have multiple medical comorbidities. In turn, neurosurgical patients are at high risk for the development of venous thromboembolism after surgery, so neurosurgeons must consider the use of pharmacologic prophylaxis. Developments in endovascular neurosurgery have produced therapies that require close management of antiplatelet medications to prevent postoperative complications. Any of these patient populations may need intrathecal access. This article highlights current strategies for managing these issues in the neurosurgical patient population.

Early and Mid-term Outcome of the St. Jude Medical Regent 19-mm Aortic Valve Mechanical Prosthesis. Functional and Haemodynamic Evaluation

BACKGROUND AND OBJECTIVES

The aim of the present study is to report the early and mid-term clinical and haemodynamic results of the St Jude Medical Regent 19-mm aortic mechanical prothesis (SJMR-19).

MATERIALS AND METHODS

Between January 2002 and January 2012, 265 patients with aortic valve disease underwent AVR (Aortic Valve Replacement) with a SJMR-19 (St Jude Medical Regent Nr.19). There were 51 males. Mean age was 67.5±12.72years and mean body surface area (BSA) was 1.67±0.14m2. Thirty-six patients required annulus enlargement. The mean follow-up was 34.5±18.8months (range 6-60 months). All patients underwent echocardiographic examination at discharge and within 1 year after surgery.

RESULTS

There were 14 (5.3%) hospital deaths. Six of the hospital deaths were identified in patients undergoing reoperation, significantly higher than patients undergoing first time operation (p=0.0001). Also the postoperative mortality was significantly higher in patients undergoing annulus enlargement versus patients not requiring annulus enlargement (p=0.02). The mean transprosthesis gradient at discharge was 19±9mmHg. At 6 months follow-up the mean NYHA FC class was 1.6±0.5 significantly lower than preoperatively 2.4±0.75 (p <0.0001). The M-TPG was 15.2±6.5mmHg within 1 year after surgery. Left ventricular mass (LVM) and indexed left ventricular mass (LVM_i) were significantly lower than preoperatively The actuarial survival and cumulative freedom from reoperation at 1, 2 and 3 years follow-up were 99.5%, 97.5%, 96.7% and 99.2%, 96.5%, 94.5% respectively. The cumulative actuarial free-events survival at 4 years was 92%. The Cox model identified age (p=0.015), LVEF≤35% (p=0.043), reoperation (p=0.031), combined surgery (p=0.00002), and annulus enlargement (p=0.015) as strong predictors for poor actuarial free-major events survival.

CONCLUSIONS

The SJMR-19 offers excellent postoperative clinical, haemodynamic outcome and LVM_i reduction in patients with small aortic annulus. These data demonstrate that the modern St Jude small mechanical protheses do not influence the intermediate free-reoperation survival.

Hemodynamic Performance and Thrombogenic Properties of a Superhydrophobic Bileaflet Mechanical Heart Valve

In this study, we explore how blood-material interactions and hemodynamics are impacted by rendering a clinical quality 25 mm St. Jude Medical Bileaflet mechanical heart valve (BMHV) superhydrophobic (SH) with the aim of reducing thrombo-embolic complications associated with BMHVs. Basic cell adhesion is evaluated to assess blood-material interactions, while hemodynamic performance is analyzed with and without the SH coating. Results show that a SH coating with a receding contact angle (CA) of 160° strikingly eliminates platelet and leukocyte adhesion to the surface. Alternatively, many platelets attach to and activate on pyrolytic carbon (receding CA = 47), the base material for BMHVs. We further show that the performance index increases by 2.5% for coated valve relative to an uncoated valve, with a maximum possible improved performance of 5%. Both valves exhibit instantaneous shear stress below 10 N/m² and Reynolds Shear Stress below 100 N/m². Therefore, a SH BMHV has the potential to relax the requirement for antiplatelet and anticoagulant drug regimens typically required for patients receiving MHVs by minimizing blood-material interactions, while having a minimal impact on hemodynamics. We show for the first time that SH-coated surfaces may be a promising direction to minimize thrombotic complications in complex devices such as heart valves.

3D velocity field characterization of prosthetic heart valve with two different valve testers by means of stereo-PIV

BACKGROUND

Prosthetic heart valves can be associated to mechanical loading of blood, potentially linked to complications (hemolysis and thrombogenicity) which can be clinically relevant. In order to test such devices in pulsatile mode, pulse duplicators (PDs) have been designed and built according to different concepts. This study was carried out to compare anemometric measurements made on the same prosthetic device, with two widely used PDs.

METHODS

The valve (a 27-mm bileaflet valve) was mounted in the aortic section of the PD. The Sheffield University PD and the RWTH Aachen PD were selected as physical models of the circulation. These two PDs differ mainly in the vertical vs horizontal realization, and in the ventricular section, which in the RWTH PD allows for storage of potential energy in the elastic walls of the ventricle. A glassblown aorta, realized according to the geometric data of the same anatomical district in healthy individuals, was positioned downstream of the valve, obtaining 1:1 geometric similarity conditions. A NaI-glycerol-water solution of suitable kinematic viscosity and, at the same time, the proper refractive index, was selected. The flow field downstream of the valve was measured by means of the stereo-PIV (Particle Image Velocimetry) technique, capable of providing the complete 3D velocity field as well as the entire Reynolds stress tensor. The measurements were carried out at the plane intersecting the valve axis.

RESULTS

A three-jet profile was clearly found in the plane crossing the leaflets, with both PDs. The extent of the typical recirculation zone in the Valsalva sinus was much larger in the RWTH PD, on account of the different duration of the swirling motion in the ventricular chamber, caused by the elasticity of the ventricle and its geometry.

CONCLUSION

The comparison of the hemodynamical behaviour of the same bileaflet valve tested in two PDs demonstrated the role of the mock loop in affecting the valve performance.

Ultrananocrystalline Diamond Integration with Pyrolytic Carbon Components of Mechanical Heart Valves

In this report, an idea of integrating ultrananocrystalline diamond (UNCD) with pyrolytic carbon (PyC) -based mechanical heart valves, has been demonstrated. The report addresses the strategies to avoid graphitization and film delamination during the diamond coating. Raman and scratch tests showed that a UNCD film with high purity could adhere to the PyC substrate strongly. A thrombin generation study demonstrated an excellent biocompatibility of UNCD towards fresh human platelets. These results suggest that UNCD could be a good candidate of surface material for next generation heart valves and other implantable devices.

Prolonged use of fondaparinux for perioperative bridging: a case report of a patient with mechanical heart valve and heparin-induced thrombocytopenia

WHAT IS KNOWN AND OBJECTIVES

Current guidelines provide no recommendations on perioperative bridging for patients after mechanical heart valve replacement (MHVR) who also have a history of heparin-induced thrombocytopenia (HIT). We present a successful case of prolonged bridging with fondaparinux in a 69-year-old Chinese woman.

CASE SUMMARY

The patient presented to our department with the aim for radical resection of oesophageal cancer. Fondaparinux has been administered alone at 2·5 mg subcutaneously once daily for 24 days during the interruption of warfarin perioperatively. There were no signs or symptoms of thromboembolic or bleeding throughout and after her hospitalization.

WHAT IS NEW AND CONCLUSION

Fondaparinux may offer an option for management of the patients with MHVR who cannot use heparin products, but further clinical investigations are warranted.

Early postoperative bridging anticoagulation after mechanical heart valve replacement: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis of studies evaluating anticoagulation during the early postoperative period following mechanical heart valve implantation.

METHODS

Five literature databases were searched to assess the rates of bleeding and thromboembolic events among patients receiving oral anticoagulation (OAC), both with and without bridging anticoagulation therapy with unfractionated heparin (UFH) or subcutaneous low molecular weight heparin (LMWH). The studies' results were pooled via a mixed effects meta-analysis. Heterogeneity (I(2) ) and publication bias were both evaluated.

RESULTS

Twenty-three studies including 9534 patients were included. The bleeding rates were 1.8% (95% confidence interval CI 1.0-3.3) in the group receiving OAC, 2.2% (95% CI 0.9-5.3) in the OAC + UFH group, and 5.5% (95% CI 2.9-10.4) in the OAC + LMWH group (P = 0.042). The thromboembolic event rate was 2.1% (95% CI 1.5-2.9) in the group receiving OAC, as compared with 1.1% (95% CI 0.7-1.8) when the bridging therapy groups were combined as follows: OAC + UFH and OAC + LMWH (P = 0.035). Most of the analyses showed moderate heterogeneity and negative test results for publication bias.

CONCLUSIONS

Bridging therapy following cardiac valve surgery was associated with a lower thromboembolic event rate, although the difference was small, with considerable overlap of the CIs. Direct comparisons are missing. Bridging therapy with UFH appears to be safe; however, this observation has a risk of bias. Early bridging therapy with LMWH appears to be associated with consistently high bleeding rates across multiple analyses. On the basis of the quality of the included studies, more trials are necessary to establish the clinical relevance of bridging therapy and the safety of LMWH.

Long-Term Comparison of Three Types of Aortic St. Jude Medical Mechanical Prosthesis in Japanese Patients

BACKGROUND

The long-term results achieved with aortic St. Jude Medical (SJM) mechanical prostheses in various age groups of Japanese patients have not been previously compared or reported.

METHODS AND RESULTS

Since 1981, a total of 240 SJM valves were implanted in 79 patients using the Standard model, in 58 patients with the Hemodynamic Plus model, and in 103 patients with the Regent model for aortic valve replacement (AVR). Follow-up was completed for 2,397 patient-years in 97.5% of the patients, among whom the effect of age was compared, and the subjects were divided into younger (<65 years) and older (≥65 years) groups. Hospital mortality rate was 2.5%. No structural valve deterioration was observed during the follow-up period. In addition, no significant differences were observed in long-term survival between the 3 models. In contrast, significantly better rates of freedom from all-cause death (P<0.0001), valve-related death (P=0.0018) and valve-related morbidity (P=0.0021), including bleeding events (P=0.0007), were observed in the younger group (n=157, 50.6±1.0 years old) than in the older group (n=83, 72.5±0.7 years old).

CONCLUSIONS

All types of SJM valve used for single AVR achieved satisfactory early and long-term results in each age group even 25 years after surgery. When selecting this prosthesis for elderly patients, however, relatively worse performance may be expected compared with that observed in younger patients.

Effect of hinge gap width of a St. Jude medical bileaflet mechanical heart valve on blood damage potential--an in vitro micro particle image velocimetry study

The hinge regions of the bileaflet mechanical heart valve (BMHV) can cause blood element damage due to nonphysiological shear stress levels and regions of flow stasis. Recently, a micro particle image velocimetry (μPIV) system was developed to study whole flow fields within BMHV hinge regions with enhanced spatial resolution under steady leakage flow conditions. However, global velocity maps under pulsatile conditions are still necessary to fully understand the blood damage potential of these valves. The current study hypothesized that the hinge gap width will affect flow fields in the hinge region. Accordingly, the blood damage potential of three St. Jude Medical (SJM) BMHVs with different hinge gap widths was investigated under pulsatile flow conditions, using a μPIV system. The results demonstrated that the hinge gap width had a significant influence during the leakage flow phase in terms of washout and shear stress characteristics. During the leakage flow, the largest hinge gap generated the highest Reynolds shear stress (RSS) magnitudes (~1000 N/m²) among the three valves at the ventricular side of the hinge. At this location, all three valves indicated viscous shear stresses (VSS) greater than 30 N/m². The smallest hinge gap exhibited the lowest level of shear stress values, but had the poorest washout flow characteristics among the three valves, demonstrating propensity for flow stasis and associated activated platelet accumulation potential. The results from this study indicate that the hinge is a critical component of the BMHV design, which needs to be optimized to find the appropriate balance between reduction in fluid shear stresses and enhanced washout during leakage flow, to ensure minimal thrombotic complications.

Hemocompatibility and Hemodynamics of Novel Hyaluronan-Polyethylene Materials for Flexible Heart Valve Leaflets

Polymeric heart valves (PHVs) hold the promise to be more durable than bioprosthetic heart valves and less thrombogenic than mechanical heart valves. We introduce a new framework to manufacture hemocompatible polymeric leaflets for HV (PHV) applications using a novel material comprised of interpenetrating networks (IPNs) of hyaluronan (HA) and linear low density polyethylene (LLDPE). We establish and characterize the feasibility of the material as a substitute leaflet material through basic hemodynamic measurements in a trileaflet configuration, in addition to demonstrating superior platelet response and clotting characteristics. Plain LLDPE sheets were swollen in a solution of silylated-HA, the silylated-HA was then crosslinked to itself before it was reverted back to native HA via hydrolysis. Leaflets were characterized with respect to (1) bending stiffness, (2) hydrophilicity, (3) whole blood clotting, and (4) cell (platelet and leukocyte) adhesion under static conditions using fresh human blood. In vitro hemodynamic testing of prototype HA/LLDPE IPN PHVs was used to assess feasibility as functional HVs. Bending stiffness was not significantly different from natural fresh leaflets. HA/LLDPE IPNs were more hydrophilic than LLDPE controls. HA/LLDPE IPNs caused less whole blood clotting and reduced cell adhesion compared to the plain LLDPE control. Prototype PHVs made with HA/LLDPE IPNs demonstrated an acceptable regurgitation fraction of 4.77 ± 0.42%, and effective orifice area in the range 2.34 ± 0.5 cm2. These results demonstrate strong potential for IPNs between HA and polymers as future hemocompatible HV leaflets. Further studies are necessary to assess durability and calcification resistance.

Antithrombotic therapy in cardiac embolism

Anticoagulation is indicated in most cardioembolic ischemic strokes for secondary prevention. In many cardiac conditions, anticoagulation is also indication for primary stroke prevention, mainly when associated to vascular risk factors. Anticoagulation should be started as soon as possible, as it is safe even in moderate acute strokes. The efficacy of early anticoagulation after cardioembolic stroke in relation to outcome has not been assessed adequately, but there is evidence from animal models and clinical studies that anticoagulation with unfractionated heparin is associated with a better outcome mediated in part by its anti-inflammatory properties.

GRADE guidelines: 9. Rating up the quality of evidence

The most common reason for rating up the quality of evidence is a large effect. GRADE suggests considering rating up quality of evidence one level when methodologically rigorous observational studies show at least a two-fold reduction or increase in risk, and rating up two levels for at least a five-fold reduction or increase in risk. Systematic review authors and guideline developers may also consider rating up quality of evidence when a dose-response gradient is present, and when all plausible confounders or biases would decrease an apparent treatment effect, or would create a spurious effect when results suggest no effect. Other considerations include the rapidity of the response, the underlying trajectory of the condition, and indirect evidence.

Antithrombotic medication for cardioembolic stroke prevention

Embolism of cardiac origin accounts for about 20% of ischemic strokes. Nonvalvular atrial fibrillation is the most frequent cause of cardioembolic stroke. Approximately 1% of population is affected by atrial fibrillation, and its prevalence is growing with ageing in the modern world. Strokes due to cardioembolism are in general severe and prone to early recurrence and have a higher long-term risk of recurrence and mortality. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardioembolism and no contraindications for anticoagulation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke. Anticoagulation therapy's associated risk of hemorrhage and monitoring requirements have encouraged the investigation of alternative therapies for individuals with atrial fibrillation. New anticoagulants being tested for prevention of stroke are low-molecular-weight heparins (LMWH), unfractionated heparin, factor Xa inhibitors, or direct thrombin inhibitors like dabigatran etexilate and rivaroxaban. The later exhibit stable pharmacokinetics obviating the need for coagulation monitoring or dose titration, and they lack clinically significant food or drug interaction. Moreover, they offer another potential that includes fixed dosing, oral administration, and rapid onset of action. There are several concerns regarding potential harm, including an increased risk for hepatotoxicity, clinically significant bleeding, and acute coronary events. Therefore, additional trials and postmarketing surveillance will be needed.

Stroke prevention in the high-risk atrial fibrillation patient: Medical management

Medical management of patients with atrial fibrillation (AF) at high risk for stroke is limited by problems of imperfect tools for assessment of thromboembolism and bleeding risks. Improved instruments, such as the CHA₂DS₂VASc and HAS-BLED risk stratification scores, have been incorporated into European practice guidelines. Until recently, the most effective therapy for stroke prevention has been anticoagulation with a vitamin K antagonist, but new oral anticoagulants in development, antiarrhythmic drugs that reduce adverse cardiovascular events in patients with AF, and interventional techniques for occlusion of the left atrial appendage represent promising options for stroke prevention. These new strategies will need focused evaluation in the most challenging AF patients-those with a high risk of bleeding, prior thromboembolism, or thrombosis-prone surfaces such as mechanical heart valve prostheses or drug-eluting coronary stents, for whom the limitations of currently available treatment options and a paucity of data are particularly acute.

Antithrombotic therapies in patients with prosthetic heart valves: guidelines translated for the clinician

Patients with prosthetic heart valves require chronic oral anticoagulation. In this clinical scenario, physicians must be mindful of the thromboembolic and bleeding risks related to chronic anticoagulant therapy. Currently, only vitamin K antagonists are approved for this indication. This paper reviews the main heart valve guidelines focusing on the use of oral anticoagulation in these patients.

Anticoagulation in the Elderly

Management of anticoagulation in elderly patients represents a particularly challenging issue. Indeed, this patient population is at high thromboembolic risk, but also at high hemorrhagic risk. Assessment of the benefit-risk balance of anticoagulation is the key point when decisions are made about introducing and/or continuing such treatments in the individual elderly patient. In order to maximise the safety of anticoagulation in the elderly, some specific considerations need to be taken into account, including renal insufficiency, modified pharmacodynamics of anticoagulants, especially vitamin K antagonists, and the presence of multiple comorbidities and concomitant medications. New anticoagulants could greatly simplify and possibly increase the safety of anticoagulation in the elderly in the near future.

A clinician's guide to perioperative bridging for patients on oral anticoagulation

Updates in recent clinical guidelines have led to a change in the management of perioperative anticoagulation for patients on oral anticoagulant therapy. No standardized bridging consensus exists in the literature. The necessity for bridging therapy is determined based on careful consideration of the thrombosis risk versus the bleeding risk of the procedure. Risk stratification will aid the decision to bridge or not to bridge. Patients are bridged with agents with appropriate kinetics to allow for their elimination prior to the time of the procedure in order to decrease the risk of hemorrhage during invasive procedures. This intent of this article is to discuss perioperative bridging therapy and provide a practical guide for the clinician.

Antithrombotic management of patients with prosthetic heart valves: current evidence and future trends

Over 4 million people worldwide have received a prosthetic heart valve, and an estimated 300,000 valves are being implanted every year. Prosthetic heart valves improve quality of life and survival of patients with severe valvular heart disease, but the need for antithrombotic therapy to prevent thrombotic complications in valve recipients poses challenges for clinicians and patients. Here, we review antithrombotic therapies for patients with prosthetic heart valves and management of thromboembolic complications. Advances in antithrombotic therapy and valve technologies are likely to improve the management of patients with prosthetic heart valves in developed countries, but the most important unmet need and potential for benefit from these new therapies is in developing countries where a massive and rapidly increasing burden of valvular heart disease exists.

Use of anticoagulants in elderly patients: practical recommendations

Elderly people represent a patient population at high thromboembolic risk, but also at high hemorrhagic risk. There is a general tendency among physicians to underuse anticoagulants in the elderly, probably both because of underestimation of thromboembolic risk and overestimation of bleeding risk. The main indications for anticoagulation are venous thromboembolism (VTE) prophylaxis in medical and surgical settings, VTE treatment, atrial fibrillation (AF) and valvular heart disease. Available anticoagulants for VTE prophylaxis and initial treatment of VTE are low molecular weight heparins (LMWH), unfractionated heparin (UFH) or synthetic anti-factor Xa pentasaccharide fondaparinux. For long-term anticoagulation vitamin K antagonists (VKA) are the first choice and only available oral anticoagulants nowadays. Assessing the benefit-risk ratio of anticoagulation is one of the most challenging issues in the individual elderly patient, patients at highest hemorrhagic risk often being those who would have the greatest benefit from anticoagulants. Some specific considerations are of utmost importance when using anticoagulants in the elderly to maximize safety of these treatments, including decreased renal function, co-morbidities and risk of falls, altered pharmacodynamics of anticoagulants especially VKAs, association with antiplatelet agents, patient education. Newer anticoagulants that are currently under study could simplify the management and increase the safety of anticoagulation in the future.

Fluid dynamics studies of cardiovascular medical devices and blood damage prediction

The implantation of cardiovascular devices such as prosthetic heart valves, even though very common in the clinical domain, is still not free from complications. Thromboembolic events and hemolysis are the major clinical problems that can occur, upon implantation. In this paper, we analyze the role of the particular fluid dynamics associated to such devices, in relation to the clinical outcome. A major issue, still debated, is the way to correlate the experimental findings with blood damage. The availability of advanced techniques such as LDA or PIV is necessary to evaluate the hemodynamical performance of a given implantable device at the local level and to draw reliable conclusions about potentially adverse clinical effects.

Comparison of INR stability between self-monitoring and standard laboratory method: preliminary results of a prospective study in 67 mechanical heart valve patients

INTRODUCTION

Thromboembolic accidents and haemorrhage are the main complications observed during long-term follow-up of mechanical heart valve patients. Several suggestions for improving anticoagulation quality have been made, including international normalised ratio (INR) self-monitoring.

OBJECTIVES

We report the preliminary results of a single-centre, open, randomised study (scheduled population of 200 patients), which compares monthly laboratory monitoring (group A) versus weekly self-monitoring of INR (group B). The primary aim is INR stability improvement within the target range, and the secondary aim is adverse events reduction.

PATIENTS AND METHODS

Between May 2004 and June 2005, 67 patients with an average age of 56.6 years (+/-9.6), were enrolled in the study (group A: 34 patients, group B: 33 patients). The mean follow-up was 47 weeks (+/-11.5). The two groups differed only in the sex ratio (44.1 and 21.2% of women in groups A and B respectively, p=0.0459). Mechanical heart valves were aortic in 73% of patients, mitral in 13.5%, and multiple in 13.5%. Sixty-five patients (97%) were treated with fluindione, the others with acenocoumarol. The intraclass correlation coefficient between the self- and laboratory-monitored INR was 0.75.

RESULTS

The time spent in the INR target range (group A: 53+/-19%, group B: 57+/--19%, p=0.45) and the time spent in the INR therapeutic range, between 2 and 4.5, (group A: 86+/-14%, group B: 91+/-7%, p=0.07) are longer in group B, but not significantly so. For patients outside the range, the absolute mean deviation of INR from the target or therapeutic range (range standardized between 0 and 100) is lower for the self-monitoring group (41.1+/-39.3 and 11.27+/-11.2) than for the control group (62.4+/-72.6 and 39.2+/-52.8). This difference is significant (p=0.0004 and p=0.0005). Eighteen adverse events were reported: 17 haemorrhages, 13 in group A (9 mild, 4 serious) and four in group B (all mild), and one sudden death in group B, two days after the patient's discharge. No thromboembolic events were reported. Six patients (8.8 %), 3 in each group, dropped out of the study.

CONCLUSION

This first study evaluating INR self-monitoring in France shows that this method leads to better stability of the INR within the target range. On the basis of these preliminary data, this appears to be related to a decrease in serious haemorrhages (11.8% serious haemorrhage cases in group A versus 0% in group B, p=0.06, NS).

Incidence of thromboembolic complications in patients with mechanical heart valves with a subtherapeutic international normalized ratio

OBJECTIVE

Subtherapeutic international normalized ratios are frequently encountered in clinical practice, and patients with mechanical heart valves with inadequate anticoagulation may be exposed to an increased risk of thromboembolic events. There are no data on thromboembolic event risk for these patients.

METHODS

We assessed the current practice patterns in the management of patients with mechanical heart valves with subtherapeutic international normalized ratios and assessed the risk of thromboembolic complications in this setting. The charts of patients with mechanical heart valves followed up in two anticoagulation clinics were reviewed. Patients with a history of stable, therapeutic anticoagulation but with a subtherapeutic international normalized ratio were included. Patients who underwent invasive procedures requiring temporary suspension of antithrombotic therapy were excluded. Data on use and dose of low-molecular weight heparin bridging therapy were collected.

RESULTS

The incidence of objectively confirmed thromboembolic events within 90 days after obtaining the index international normalized ratio was assessed. Two hundred ninety-four patients with mechanical heart valves were included (mean age 63.3 years, 47.3% male). Low-molecular weight heparin was prescribed in 14 cases (4.8%). At 90 days, 1 patient had a thromboembolic complication (0.3%, 95% confidence interval 0%-1.9%).

CONCLUSION

Patients with previously stable, therapeutic anticoagulation with a subtherapeutic international normalized ratio have a low risk of thromboembolic events. Withholding low-molecular weight heparin bridging therapy is a reasonable therapeutic option in these cases.

Guideline on antiplatelet and anticoagulation management in cardiac surgery

This document presents a professional view of evidence-based recommendations around the issues of antiplatelet and anticoagulation management in cardiac surgery. It was prepared by the Audit and Guidelines Committee of the European Association for Cardio-Thoracic Surgery (EACTS). We review the following topics: evidence for aspirin, clopidogrel and warfarin cessation prior to cardiac surgery; perioperative interventions to reduce bleeding including the use of aprotinin and tranexamic acid; the use of thromboelastography to guide blood product usage; protamine reversal of heparin; the use of factor VIIa to control severe bleeding; anticoagulation after mechanical, tissue valve replacement and mitral valve repair; the use of antiplatelets and clopidogrel after cardiac surgery to improve graft patency and reduce thromboembolic complications and thromboprophylaxis in the postoperative period. This guideline is subject to continuous informal review, and when new evidence becomes available. The formal review date will be at 5 years from publication (September 2013).