Loss of engagement in controlling chronic anticoagulation therapy during Covid-19 stringency measures. A single center experience of disproportioned increase of stuck mechanical valves

Stuck valve is a very rare and severe complication that occurs in mechanical valve replacement patients with ineffective anticoagulation. However, with COVID-19 restriction measures, it became challenging to regularly assess INR to make sure it falls within the target therapeutic range to prevent this complication. We present a series of 10 patients who either underwent transthoracic echocardiography for a suspected stuck valve or were seen at the outpatient valve clinic with the residual consequences of a stuck valve during the COVID-19 restriction measures in our institute. Stuck prosthetic valves incident has increased significantly during this period, particularly those in the mitral position for which urgent replacement and prolonged hospitalization were necessary. Particularly with the COVID-19 restrictions in place, these cases highlight the need for physicians to be aware of the dramatic increase in the incidence of stuck prosthetic valves in patients on chronic warfarin therapy.

Surgical techniques for aortic valve xenotransplantation

Background Heart valve replacement in neonates and infants is one of the remaining unsolved problems in cardiac surgery because conventional valve prostheses do not grow with the children. Similarly, heart valve replacement in children and young adults with contraindications to anticoagulation remains an unsolved problem because mechanical valves are thrombogenic and bioprosthetic valves are prone to early degeneration. Therefore, there is an urgent clinical need for growing heart valve replacements that are durable without the need for anticoagulation. Methods A human cadaver model was used to develop surgical techniques for aortic valve xenotransplantation. Results Aortic valve xenotransplantation is technically feasible. Subcoronary implantation of the valve avoids the need for a root replacement. Conclusion Aortic valve xenotransplantation is promising because the development of GTKO.hCD46.hTBM transgenic pigs has brought xenotransplantation within clinical reach.

Permanent pacemaker implantation after On-X surgical aortic valve replacement: SWEDEHEART observational study

ObjectiveBioprosthetic aortic valves with an extended subannular component, such as transcatheter valves, exert increased compression on the cardiac conduction system and increase the risk for permanent pacemaker implantation. It is unknown if the On-X mechanical prosthetic valve, which has an elongated subannular valve housing, increases the risk of permanent pacemaker implantation following aortic valve replacement.DesignObservational nationwide cohort study.SettingSwedish population-based study.ParticipantsAll patients aged 18–65 years who underwent primary mechanical aortic valve replacement in Sweden between 2005 and 2018. We used the Swedish Web system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies register and other Swedish national health-data registers.ExposurePatients implanted with an On-X valve versus patients implanted with other bileaflet mechanical valves.Primary and secondary outcome measuresPrimary outcome measure was permanent pacemaker implantation within 30 days of surgery.ResultsA total of 2602 patients were included, and 581 patients received an On-X valve and 2021 patients received a St Jude Masters/Regent (n=945) or Carbomedics Reduced valve (n=1076). In the total study population, 115 (4.4%) permanent pacemaker implantations were performed within 30 days after aortic valve replacement. In the propensity score matched population, there was no significant difference in the rate of permanent pacemaker implantation in the On-X group compared with the control group: 3.6% (95% CI: 2.4% to 5.5%) vs 4.0% (95% CI: 2.7% to 5.9%), p=0.877.ConclusionsThe On-X prosthetic heart valve was associated with a similarly low risk for permanent pacemaker implantation after aortic valve replacement compared with other conventional bileaflet mechanical valves. The On-X elongated subannular valve housing does not interfere with the cardiac conduction system.

Utilization and complications of catheter ablation for ventricular arrhythmias in patients with mechanical valves

Background Catheter ablation (CA) for ventricular arrhythmias (VAs) is increasingly utilized in the recent years. Ablation for VAs in patients with mechanical valves (MVs), can be challenging due to the chronic anticoagulation therapy, limitations in accessing the cardiac chambers, the risk for entrapment of mapping or ablation catheters between the leaflets of MVs and more. Purpose To investigate the nationwide trends in utilization and complications of CA for VAs in patients with prior MVs. Methods We drew data from the US National Inpatient Sample database to identify cases of VA ablations, including premature ventricular contraction (PVC) and ventricular tachycardia (VT) ablations, in patients with MVs between 2003 and 2015. Sociodemographic and clinical data were collected, and incidence of catheter ablation complications, mortality, and length of stay were analyzed. We compared the outcomes to a propensity matched cohort of patients without prior valve surgery. Results The study population included a weighted total of 647 CA cases in patients with prior MVs. The annual number of ablations almost doubled, from 34 ablations on average during the “early years” (2003–2008) to 64 annual ablation procedures on average during the “late years” (2009–2015) of the study (p=0.001). Length of stay at the hospital did not differ significantly between patients with MVs and 649 matched patients without prior MVs (5.4±0.4, 4.7±0.3 days respectively, p=0.12). The incidence of complications was higher among patients with and without MVs (12.6% vs. 7.5% respectively, p=0.14), however, not reaching statistical significance. Moreover, the data revealed a trend toward higher mortality among patients with MVs undergoing CA compared to matched control patients without MVs (3.7% vs. 0.7% respectively, p=0.087). Conclusion The utilization of catheter ablations for ventricular arrhythmias in patients with mechanical valves increased substantially over the years. The data show a trend towards increased incidence of morality and complications in the study population, requiring further investigation in larger population cohort. FUNDunding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Padeh Medical Center Research Fund

Anticoagulants and antiaggregants in the COVID-19 era

Review of the latest scientific data and the main provisions of clinical guidelines on the use of anticoagulants and antiaggregants in patients with COVID-19 is presented. A separate part of the paper focuses on the use of prasugrel in this group of patients. The main trend in the use of anticoagulants for the prevention of venous thromboembolism in COVID-19 infection can be considered as a decrease in drug activity. Thus, the experts of the American Hematological Society suggest using low doses of oral or parenteral anticoagulants for thromboprophylaxis in hospitalized patients, preferring them to intermediate or high doses. Virtually all experts agree that prophylactic anticoagulant use should be avoided in clinical practice in patients with COVID-19 who are on outpatient treatment (whether it was chosen as an initial tactic or was a continuation of inpatient treatment). The principles for the therapeutic use of anticoagulants in COVID-19 should be based on already existing clinical guidelines for the conditions that require anticoagulants (atrial fibrillation, venous thrombosis or thromboembolism, presence of mechanical valves, etc.). The use of antiaggregants in patients with COVID-19 outside their registered indications is currently continuing to be studied in several clinical trials. That said, as part of dual antiplatelet therapy after percutaneous coronary intervention for COVID-19, it is advisable to continue this treatment without cancelling any of its components without a specific indication. The same is true for prasugrel, which remains one of the first recommended potent P2Y12 inhibitors.

ORAL ANTICOAGULANTS: CHALLENGES IN PAKISTAN. DO WE HAVE A SOLUTION?

The common public health problem in thromboembolic disorders (TED) are venous thromboembolism (VTE) and stroke caused by Atrial Fibrillation (AF).1 The main stay of treatment among oral anticoagulants are Vit K antagonist (VKAs) like warfarin and acenocoumarin, warfarin has been the most commonly used drug particularly in Pakistan. However now Non Vitamin K dependent oral anticoagulants (NOACs) such as dabigatrin, rivaroxaban and apixaban have come in to use.2 Till now VKAs are most extensively used in developing countries like India3 & Pakistan because of their effects can easily be reversed, and they are safe in impaired renal function besides being cost effective. The problems encountered with VKAs relate to dietary patterns in the region resulting in drug interaction, over usage of non-steroidal anti-inflammatory drugs (NSAIDs) and most important the lack of lab facilities to monitor international normalized ratio (INR), and finally the lack of awareness of target INR levels by physicians & patients. Oral anticoagulants are the main stay in the prevention of stroke in patients with valvular and non valvular Atrial Fibrillation.4 The preferred oral anticoagulants with mechanical heart valves and severe mitral stenosis are the VKAs while for others stroke risk stratification is done by CHADS2-VASC score.5 If CHADS2-VASC score is of 3 in non valvular AF NOACS can be initiated. The main challenge for stroke prevention is in pregnant women with AF who have either mechanical valve or severe valvular disease (Mitral Valve disease) in adjusting VKAs dose. Low molecular weight Heparin (LMWH) is considered to be safe option6 in first trimester and before delivery. The recommended dose of warfarin in women with or without mechanical valves is ≤ 5 mg/day throughout pregnancy, however during the first trimester dose adjusted LMWH is given to avoid teratogenic effects. Warfarin is continued in second and third trimesters and I/V unfractionated Heparin / LMWH in the peripartum period.7 The gynecologists being primary care givers should be trained in this respect to avoid any kind of complications. Another problem is to bridge antithrombin therapy in VHD patient schedule for surgery. The clinicians deciding factor for temporary stoppage of VKAs therapy is the type of heart valve prosthesis.8 Surgeon and anesthetist posted in rural health center in Pakistan should be provided management guidelines in the form of small printed cards in simple language. Knowledge of management of prosthetic valve complication9 and stroke management10 needs to be addressed especially in public hospitals. In conclusion vitamin K antagonists such as warfarin is most commonly used in the Pakistan for valid reasons as mentioned. Awareness of PT/INR level to a therapeutic range to be made to patients and physicians by establishing anticoagulation clinics in all public hospitals throughout the country. NOACs to be initiated with appropriate use of CHADS2-VASC score with their appropriate indication and contraindication. Information leaflets on Anticogulation benefits, complications and interactions should be provided in local languages to the patients and they should keep a record of their INR values. Efforts should be made by various agencies in particular Ministry of NHS TO ensure uninterrupted availability of anticoagulants and cheap lab tests. Although international evidence based guidelines do exist, they do not address specific goals required by ours patients. To enhance knowledge of our clinician regarding Vit K antagonist and NOACS its important to set local guidelines for various case-based scenarios. References Amin A, Marrs JC. Direct oral anticoagulants for the management of thromboembolic disorders: the importance of adherence and persistence in achieving beneficial outcomes. Clin Appl Thromb Hemost. 2016;22(7):605-16. Mekaj YH, Mekaj AY, Duci SB, Miftari EI. New oral anticoagulants: their advantages and disadvantages compared with vitamin K antagonists in the prevention and treatment of patients with thromboembolic events. Ther Clin Risk Manag. 2015;11:967. Menon A, Thomas J, Ichaporia NR, Sahoo PK, Unni TG. Oral anticoagulation therapy: current challenges in Indian scenario. Int J Adv Med 2020;7:1044-52. Asinger RW, Shroff GR, Simegn MA, Herzog CA. Anticoagulation for Nonvalvular atrial fibrillation: influence of epidemiologic trends and clinical practice patterns on risk stratification and net clinical benefit. Circ Cardiovasc Qual Outcom. 2017;10(9):e003669. Alshawabkeh L, Economy KE, Valente AM. Anticoagulation during pregnancy: evolving strategies with a focus on mechanical valves. J Am Coll Cardiol. 2016;68(16):1804-13. Kirchhof P, Benussi S, Kotecha D, Ahlsson A, Atar D, Casadei B, et al. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J. 2016;50(5):e1-88. Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP, Fleisher LA, et al. 2017 AHA/ACC focused update of the 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017;70(2):252-89. Saksena D, Muralidharan S, Mishra YK, Kanhere V, Mohanty BB, Srivastava CP, et al. Anticoagulation Management in Patients with Valve Replacement. J Assoc Physicians India. 2018;66(1):59-74. Powers WJ, Rabinstein AA, Ackerson T, Adeoye OM, Bambakidis NC, Becker K, et al. 2018 guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2018;49(3):e46-99. Morgenstern LB, Hemphill III JC, Anderson C, Becker K, Broderick JP, Connolly Jr ES, et al. Guidelines for the management of spontaneous intracerebral hemorrhage: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2010;41(9):2108-29.

Predictors of Use and Outcomes of Mechanical Valve Replacement in the United States (2008–2017)

Background Contemporary nationwide data on the use, predictors, and outcomes of mechanical valve replacement in patients less than 70 years of age are limited. Methods and Results We identified hospitalizations for aortic valve replacement (AVR) or mitral valve replacement (MVR) in the Nationwide Inpatient Sample between January 1, 2008, and December 31, 2017. The study's end points included predictors of mechanical valve replacement and risk‐adjusted in‐hospital mortality. Among 253 100 hospitalizations for AVR, the use rate of mechanical prosthesis decreased from 45.3% in 2008 to 17.0% in 2017. Among 284 962 hospitalizations for MVR, mechanical prosthesis use decreased from 59.5% in 2008 to 29.2% in 2017 ( P for trend<0.001). In multilogistic regression analyses, female sex, prior sternotomy, prior defibrillator, and South/West geographic location were predictive of mechanical valve use. The presence of bicuspid valve was a negative predictor of mechanical AVR (odds ratio [OR], 0.68; 95% CI, 0.66–0.69; P <0.001), whereas mitral stenosis was associated with higher mechanical MVR (OR, 1.28; 95% CI, 1.22–1.33; P <0.001). Unadjusted in‐hospital mortality decreased over time with AVR but not with MVR, regardless of prosthesis choice. Using years 2008 and 2009 as a reference, risk‐adjusted mortality also decreased over time with AVR but did not decrease after MVR. Conclusions There is a substantial decline in the use of mechanical valve replacement among patients aged ≤70 years in the United States. Long‐term durability data on bioprosthetic valve replacement are needed to better define the future role of mechanical valves in this age group.