Outcomes of Patients with a Mechanical Heart Valve and Poor Anticoagulation Control on Warfarin

Prosthetic valve dysfunction in patients with mechanical heart valves: Results from the Emergency Salam Centre cohort

INTRODUCTION

Mechanical heart valve (MHV) replacement requires long-life anticoagulation due to the risk of Prosthetic Valve Dysfunction (PVD) and cardioembolism.

METHODS

We report data from a prospective observational study conducted on MHV patients in the Khartoum Salam Centre for Cardiac Surgery built by 'Emergency,' an Italian Non-Governmental Organization, to evaluate the occurrence of PVD and associated risk factors.

RESULTS

We prospectively followed 3647 patients, and 38 patients (rate 1.04 × 100 pt-years) had PVD during follow-up. The time in therapeutic range (TTR) among patients without PVD was 53 % (IQR 37-67), and it was 43 % (IQR 19-58) among patients with PVD (p = 0.04). Twenty-three over 38 patients (60.5 %) were symptomatic, 18 (47.4 %) had obstructive valvular stenosis, 24 patients (63.2 %) had INR <2.0 at diagnosis, and 21 patients (55.3 %) had been off warfarin for a long time: 3 patients for 1 week, 1 patient for 2 weeks, and 17 patients for >4 weeks (6 patients were off warfarin from 3 to 12 months). Ten were uncompliant to treatment, and 8 were pregnant women. Ten patients (26.3 %) with PVD had had a previous episode of PVD, and 14 patients (36.8 %) had 2 or more associated risk factors. Only in 6 cases were no associate risk factors found.

CONCLUSIONS

Among MHV patients on warfarin treatment with a sub-optimal quality of anticoagulation, the rate of PVD is 1.04 % pt-years, and the most frequent associated risk factor for PVD occurrence is warfarin withdrawal lasting more than one week.

Long-Term Risk of Hospitalization and Death in Patients With Mechanical Prosthetic Heart Valves

Mechanical prosthetic heart valves (MPHVs) are commonly used for valvular heart disease in patients with a long life expectancy. Few longitudinal data on the specific causes of hospitalization in patients with MPHV are available. We investigated the risk of all-cause hospitalization and mortality in patients with MPHV. We performed a prospective, observational, ongoing study including consecutive patients with MPHVs who were referred to the atherothrombosis outpatient clinic of the Policlinico Umberto I of Rome for the vitamin K antagonist management. Study end points were all-cause, cardiovascular hospitalization, and overall mortality. We included 305 patients with MPHV (38.4% women, median age 60.2 years). The site of MPHV was aortic in 53.5%, mitral in 29.5%, and mitroaortic in 17%. During a median follow-up of 57.3 months, 142 hospitalizations occurred (8.16 per 100 person-years). The most common causes of hospitalization were cardiovascular disease (3.62 per 100 person-years), infections, surgery, and bleeding. The predictors of cardiovascular hospitalization were atrial fibrillation (hazard ratio [HR] 1.75, 95% confidence interval [CI] 1.04 to 2.95, p = 0.035), previous stroke/transient ischemic attack (HR 2.96, 95% CI 1.59 to 5.48, p = 0.001), and peripheral artery disease (HR 2.42, 95% CI 1.09 to 5.36, p = 0.030). During a median follow-up of 97.2 months, 61 deaths occurred (2.43 per 100 person-years). Age was directly associated with the risk of death (HR 1.088, 95% CI 1.054 to 1.122, p <0.001), whereas the time in therapeutic range higher than the median was inversely associated (HR 0.436, 95% CI 0.242 to 0.786, p = 0.006). In conclusion, patients with MPHV had a high incidence of hospitalizations, especially cardiovascular-related. The incidence of death is high; however, it may be decreased by maintaining a good quality of anticoagulation.

Association between gene polymorphisms and initial warfarin therapy in patients after heart valve surgery

BACKGROUND

Warfarin is widely used for the prevention and treatment of thrombotic events. This study aimed to examine the influence of gene polymorphisms on the early stage of warfarin therapy in patients following heart valve surgery.

METHODS

Nine single nucleotide polymorphisms were genotyped using microarray chips, categorizing patients into three groups: normal responders (Group I), sensitive responders (Group II), and highly sensitive responders (Group III). The primary clinical outcomes examined were time in therapeutic range (TTR) and international normalized ratio (INR) variability. To investigate potential influencing factors, a generalized linear regression model was employed.

RESULTS

Among 734 patients, the prevalence of CYP2C9*3-1075A > C, CYP2C19*3-636G > A, and CYP2C19*17-806C > T variants were 11.2%, 9.9%, and 1.9% of patients, respectively. VKORC1-1639G > A or the linked -1173C > T variant was observed in 99.0% of the patients. Generalized linear model analysis revealed an impact of sensitivity grouping on INR variability. Compared to Group I, Group II showed higher TTR values (p = 0.023), while INR variability was poorer in Group II (p < 0.001) and Group III (p < 0.001). Individual gene analysis identified significant associations between CYP2C9*3-1075A > C (p < 0.001), VKORC1-1639G > A or the linked -1173 C > T (p = 0.009) and GGCX-3261G > A (p = 0.019) with INR variability.

CONCLUSION

The genotypes of CYP2C9, VKORC1, and GGCX were found to have a significant impact on INR variability during the initial phase of warfarin therapy. However, no significant association was observed between TTR and gene polymorphisms. These findings suggest that focusing on INR variability is crucial in clinical practice, and preoperative detection of gene polymorphisms should be considered to assist in the initiation of warfarin therapy.