Anticoagulation for mechanical heart valves: a role for patient based therapy

Psychological Status and Warfarin Therapy in Patients after Valve Replacement during the COVID-19 Pandemic: A Cross-sectional Study

OBJECTIVE

The standardization of warfarin anticoagulant therapy is the key to lifelong treatment for patients after heart valve replacement. The present study explored the possible risk factors for anxiety and depression during the coronavirus disease 2019 (COVID-19) pandemic and analyzed the influence of psychological state on medication safety.

METHODS

Eligible patients received a web-based questionnaire survey via the Wenjuanxing platform during outpatient visits. Depression was evaluated by the Self-Rating Depression Scale (SDS). Anxiety was evaluated by the Self-Rating Anxiety Scale (SAS). Medication adherence was evaluated by the Morisky scale.

RESULTS

A total of 309 patients (aged 52.2±11.4 years) were included in the present study. The SDS score of all included patients was 36.9±9.4 points, of which 11 (3.6%) patients were diagnosed as having depression. The SAS score of all included patients was 43.1±9.3 points, of which 71 (23%) patients were diagnosed as having anxiety. Seven patients (2.3%) had both anxiety and depression. Logistic regression analysis revealed that only monthly income was an independent influencing factor for depression. Regarding anxiety, patients who underwent repeated operations had a 2.264-fold greater risk, and patients who received combination medication had a 2.140-fold greater risk. More bleeding events and coagulation disorders could be observed in patients with anxiety, depression or both. When anxiety occurred, patients showed worse medication adherence. However, depression had no significant effect on medication adherence.

CONCLUSION

During the COVID-19 pandemic, the detection rate of mental illnesses such as anxiety and depression was high, which seriously affected the medication safety of warfarin. Analysis of its influencing factors will provide a reference for further standardized regulation of warfarin anticoagulant therapy after valve replacement.

Mechanical Valves: Past, Present, and Future-A Review

The mechanical valve was first invented in the 1950s, and since then, a wide variety of prostheses have been developed. Although mechanical valves have outstanding durability, their use necessitates life-long treatment with anticoagulants, which increases the risk of bleeding and thromboembolic events. The current guidelines recommend a mechanical prosthetic valve in patients under 50-60 years; however, for patients aged 50-70 years, the data are conflicting and there is not a clear-cut recommendation. In recent decades, progress has been made in several areas. First, the On-X mechanical valve was introduced; this valve has a lower anticoagulant requirement in the aortic position. Second, a potential alternative to vitamin K-antagonist treatment, rivaroxaban, has shown encouraging results in small-scale trials and is currently being tested in a large randomized clinical trial. Lastly, an innovative mechanical valve that eliminates the need for anticoagulant therapy is under development. We attempted to review the current literature on the subject with special emphasis on the role of mechanical valves in the current era and discuss alternatives and future innovations.

Challenges Faced and Lessons Learned: The Journey of a 22-Year-Old Male with a Mechanical Heart Valve Complicated by Ischemic Stroke in a Developing Country: A Sub-Saharan Africa Prospect

This report reviews an Ethiopian patient who underwent cardiac surgery and had a mechanical heart valve implanted on the mitral valve with tricuspid valve repair for rheumatic heart disease via a local non-profit organization donation later complicated by cardio-embolic stroke, and aims to describe the challenges faced by patients from rural Ethiopia who require cardiac surgery for rheumatic heart disease and narrate the importance of careful follow-up. The lessons to be drawn from this case are that careful follow-up and adherence to prescribed Vitamin K antagonists after surgery for mechanical heart valves are critical and, when such patients are lost to follow-up as was witnessed in this case, it can induce lifelong morbidity. Morbidity that could have been avoided with strict and meticulous follow-up and with standardized patient tracing or contact systems. When patients are lost to follow-up it needs to be top priority to trace them after cardiac surgery and this report highlights the pivotal role of the health education in such populations. Unless we utilize this opportunity to unlock the door and embrace a systemic approach to reforming our risk assessment, referral chain system, and integration of various healthcare professionals in patient follow-up, as well as enhancing health education among our patients in rural Ethiopia and other low-income countries, the consequences could prove to be significant. Preventing such fatal complications is far superior to managing them afterwards, as it not only saves on expenses but also saves lives and enhances quality-of-life.

Improved stacking ensemble learning based on feature selection to accurately predict warfarin dose

Background

With the rapid development of artificial intelligence, prediction of warfarin dose via machine learning has received more and more attention. Since the dose prediction involve both linear and nonlinear problems, traditional machine learning algorithms are ineffective to solve such problems at one time.

Objective

Based on the characteristics of clinical data of Chinese warfarin patients, an improved stacking ensemble learning can achieve higher prediction accuracy.

Methods

Information of 641 patients from southern China who had reached a steady state on warfarin was collected, including demographic information, medical history, genotype, and co-medication status. The dataset was randomly divided into a training set (90%) and a test set (10%). The predictive capability is evaluated on a new test set generated by stacking ensemble learning. Additional factors associated with warfarin dose were discovered by feature selection methods.

Results

A newly proposed heuristic-stacking ensemble learning performs better than traditional-stacking ensemble learning in key metrics such as accuracy of ideal dose (73.44%, 71.88%), mean absolute errors (0.11 mg/day, 0.13 mg/day), root mean square errors (0.18 mg/day, 0.20 mg/day) and R2 (0.87, 0.82).

Conclusions

The developed heuristic-stacking ensemble learning can satisfactorily predict warfarin dose with high accuracy. A relationship between hypertension, a history of severe preoperative embolism, and warfarin dose is found, which provides a useful reference for the warfarin dose administration in the future.

Current Therapeutic Options in Aortic Stenosis

Aortic stenosis is the most common valvular disease requiring valve replacement. Valve replacement therapies have undergone progressive evolution since the 1960s. Over the last 20 years, transcatheter aortic valve replacement has radically transformed the care of aortic stenosis, such that it is now the treatment of choice for many, particularly elderly, patients. This review provides an overview of the pathophysiology, presentation, diagnosis, indications for intervention, and current therapeutic options for aortic stenosis.

Effects of a Personalized Nurse-Led Educational Program for New Patients Receiving Oral Anticoagulant Therapy after Mechanical Heart Valve Prosthesis Implantation on Adherence to Treatment

Background

Life-long anticoagulant therapy is mandatory for patients who undergo heart valve replacement with implantation of a mechanical prosthesis. The aim of this study was to investigate the effects of a nurse-led patient educational program concerning oral anticoagulant therapy intake after heart valve replacement surgery on patients’ knowledge of important parameters of anticoagulant administration.

Methods

In this single-center study, 200 patients who underwent surgical implantation of a mechanical prosthesis were divided into 2 groups. The control group received the basic education concerning oral anticoagulants, while the intervention group received a personalized educational program.

Results

Personalized education was correlated with a better regulation of therapeutic international normalized ratio (INR) levels and adequate knowledge among patients. Therapeutic levels of INR were achieved in 45% of the patients during the first month, 71% in the third month, and 89% in the sixth month after discharge in the intervention group, compared to 25%, 47%, and 76% in the control group, respectively. Patients’ satisfaction with the information was higher in the intervention group than in the control group. The percentage of satisfaction reached 80% for the intervention group versus 37% for the patients of the control group.

Conclusion

The implementation of the nurse-led educational programs was associated with improved clinical results and increased adherence to oral anticoagulant treatment.

Thirty-year experience with a bileaflet mechanical valve prosthesis

BACKGROUND

The objective was to evaluate the long-term outcomes of the St Jude Medical (Saint Paul, Minn) mechanical valve prosthesis implantation.

METHODS

Since 1979, every patient receiving this prosthesis has been followed annually.

RESULTS

From January 1979 to December 2014, 1023 patients were accrued. Patients' ages ranged from 18 to 85 years. Aortic valve replacement was performed in 584 patients, and mitral valve replacement was performed in 439 patients. Follow-up was 95% complete. Operative mortality was 3% (17/584, aortic valve replacement) and 4% (18/439, mitral valve replacement). In patients undergoing aortic valve replacement, late actuarial survival was 62% ± 2%, 32% ± 2%, and 14% ± 3% at 10, 20, and 30 years, respectively. Thirty-year freedom from reoperation, thromboembolism, valve thrombosis, bleeding, and endocarditis was 92% ± 2%, 79% ± 3%, 96% ± 1%, 56% ± 5%, and 92% ± 2%, respectively. In patients undergoing mitral valve replacement, late actuarial survival was 64% ± 3%, 28% ± 3%, and 14% ± 3% at 10, 20, and 30 years, respectively. Thirty-year freedom from reoperation, thromboembolism, valve thrombosis, bleeding, and endocarditis was 85% ± 5%, 55% ± 6%, 99% ± 1%, 57% ± 6%, and 95% ± 2%, respectively. The incidence of bleeding was 2.5% and 2.0% per patient-year for aortic valve replacement and mitral valve replacement, respectively. The incidence of thromboembolism was 1.6% and 2.9% per patient-year for aortic valve replacement and mitral valve replacement, respectively.

CONCLUSIONS

Annual follow-up of all of our patients receiving a St Jude Medical mechanical valves prosthesis has allowed better identification valve-related issues and events. After 3 decades of observation with close follow-up, the St Jude Medical mechanical valve continues to be a reliable prosthesis.

Anticoagulant independent mechanical heart valves: viable now or still a distant holy grail

Valvular heart disease remains a large public health problem for all societies; it attracts the attention of public health organizations, researchers and governments. Valve substitution is an integral part of the treatment for this condition. At present, the choice of valve prosthesis is either tissue or mechanical. Tissue valves have become increasingly popular in spite of unresolved problems with durability, hemodynamics, cost and need for anticoagulation therapy. As a consequence, mechanical valve innovation has virtually ceased; the last successful mechanical design is 25 years old. We postulate that with improved technology, knowledge and experience gained over the last quarter century, the best possible solution to the problem of valve substitution can be achieved with a mechanical valve that is anticoagulant independent, durable, hemodynamically and cost efficient. At present, it is possible to design, test and produce a valve that can accomplish these goals.

Longest Event-Free Survival without Anticoagulation in a Mechanical Aortic Valve Replacement

Sixty percent of the patients going for valve replacement opt for mechanical valves and the remaining 40% choose bioprosthetics. Mechanical valves are known to have a higher risk of thrombosis; this risk further varies depending on the type of valve, its position, and certain individual factors. According to current guidelines, long-term anticoagulation is indicated in patients with metallic prosthetic valve disease. We report two unique cases of patients who survived 27 and 37 years event free, respectively, after mechanical aortic valve replacement (AVR) without being on any form of anticoagulation. The latter case described the longest survival in a human with a prosthetic aortic valve without anticoagulation. A review of literature demonstrated few cases of prosthetic valves with no anticoagulation in the long term without significant embolic events reported as case reports. These cases have been summarized in this article. Some cases of long-term survival (in the absence of anticoagulation) were attributed to good luck, and others as the result of genetic variations. New mechanical prosthetic valves can be promising, such as microporus-surfaced valves that may be used without full anticoagulation. The use of dual antiplatelet agents alone can be currently recommended only when a patient cannot take oral anticoagulation after AVR, and it should be followed with measuring and monitoring of platelet reactivity.

Comparison of the occurrence of thromboembolic and bleeding complications in patients with mechanical heart valve prosthesis with one and two leaflets in the mitral position

INTRODUCTION

Patients with mechanical heart valve prostheses must continuously be treated with oral anticoagulants to prevent thromboembolic events related to prosthetesis. These patients should be continually evaluated for the control of oral anticoagulation.

OBJECTIVE

To compare the occurrence of thromboembolic and hemorragic complications in patients with mechanical heart valve prosthesis with one (mono) and two (bi) leaflets in the mitral position in anticoagulant therapy.

METHODS

We studied the 10-year interval, 117 patients with prosthesis in the mitral position, 48 with prosthetic single leaflet and 69 with two leaflets. We evaluated the occurrence of thromboembolic and hemorrhagic major and minor degree under gravity. The results are presented in an actuarial study and the frequency of occurrence of linear events.

RESULTS

The actuarial survival curves showed that over time, patients with prosthetic heart valve with one leaflet were less free of thromboembolic complications than patients with two leaflet prosthetic valve, while the latter (two leaflet) were less free of hemorrhagic accidents. The linearized frequency of occurrence of thromboembolism were higher in patients with mono leaflet prosthesis. Bleeding rates were higher for patients with bi leaflet prosthetic valve.

CONCLUSION

Patients with mono leaflet prosthetic heart valve showed that they are more prone to the occurrence of serious thromboembolic events compared to those with bi leaflet prosthetic valve. Patients with bi leaflet prosthetic valve had more bleeding than patients with mono leaflet prosthetic valve, however this difference was restricted to the bleeding of minor nature.

Twenty-year single-center experience with the medtronic open pivot mechanical heart valve

BACKGROUND

Since May 1992 the Medtronic Open Pivot mechanical heart valve has been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 20-year clinical results of the valve.

METHODS

Between May 1992 and December 2011 a total of 1,520 valves was inserted into 1,382 consecutive patients (1,012 aortic, 473 mitral, 26 tricuspid, 9 pulmonary). The mean age of the patients was 61±13.2 years. Preoperatively, 65% of the patients were in New York Heart Association (NYHA) class III or greater. Frequent comorbidities included atrial fibrillation (n=419), coronary disease (n=357), and diabetes (n=255). The 99% complete follow-up totaled 10,527 patient-years (range 12 to 244 months).

RESULTS

Ninety-day mortality was 5.2% (n=73, 8 valve related). Of the 550 total deaths, 240 were cardiac and 56 valve related. Multivariate analysis selected age, NYHA III or greater, concomitant coronary revascularization, and respiratory insufficiency as risk factors for death. Renal failure was considered a risk factor in the aortic and atrial fibrillation in the mitral subgroup. Erratic international normalized ratio (INR), NYHA class III or greater, and non-sinus rhythm were risk factors for thromboembolism; likewise redo operations in the aortic subgroup. Erratic INR and age were risk factors for bleeding as were over-coagulation and coronary revascularization in the aortic subgroup and redo operations and renal failure in mitral patients.

CONCLUSIONS

This 20-year experience demonstrated excellent clinical outcomes with no structural valve failure. Odds ratio defined aortic patients as the lowest risk for adverse events. By contrast atrial fibrillation and elderly age, in combination with instable anticoagulation, yielded the worst long-term results.

Effect of hypertension on the closing dynamics and Lagrangian blood damage index measure of the b-datum regurgitant jet in a bileaflet mechanical heart valve

We hypothesize that the formation of the closing vortex and subsequent b-datum regurgitation jet in bileaflet mechanical heart valves is governed by the magnitude of the driving mean aortic pressure (MAP), and that this sensitivity does impact the blood damage index (BDI) corresponding to platelet activation and lysis. High spatial resolution time resolved (1 kHz) as well as phase locked particle image velocimetry techniques captured the dynamic leaflet closure and regurgitation jet of a model 25 mm St. Jude Medical BMHV. Cell trajectories were estimated using Lagrangian particle tracking analysis while the leaflet kinematics was quantified by tracking the leaflet tip-position throughout closure. The non-principal as well as principal shear stress loading histories along each cell trajectory revealed BDI for platelet activation and lysis as a function of cell initial position, release time-point, and blood pressure. Results show that the leaflet closing time reduces by roughly 10 ms, in response to an increase in MAP by 40 mmHg. We report that higher MAP leads to a stronger b-datum vortex and jet formation. Platelet activation BDI lowers with a higher MAP due to reduction in exposure times despite an increase in principal shear stress experienced. Platelet lysis BDI however increases with higher MAP. Maximum BDI may occur for cells initially in the b-datum zone during the onset of leaflet closure. Our results provide a better understanding of BDI of the regurgitant b-datum jet and sheds light on the potential importance of blood damage testing under hypertensive conditions.