Rivaroxaban in Rheumatic Heart Disease-Associated Atrial Fibrillation

BACKGROUND

Testing of factor Xa inhibitors for the prevention of cardiovascular events in patients with rheumatic heart disease-associated atrial fibrillation has been limited.

METHODS

We enrolled patients with atrial fibrillation and echocardiographically documented rheumatic heart disease who had any of the following: a CHA2DS2VASc score of at least 2 (on a scale from 0 to 9, with higher scores indicating a higher risk of stroke), a mitral-valve area of no more than 2 cm2, left atrial spontaneous echo contrast, or left atrial thrombus. Patients were randomly assigned to receive standard doses of rivaroxaban or dose-adjusted vitamin K antagonist. The primary efficacy outcome was a composite of stroke, systemic embolism, myocardial infarction, or death from vascular (cardiac or noncardiac) or unknown causes. We hypothesized that rivaroxaban therapy would be noninferior to vitamin K antagonist therapy. The primary safety outcome was major bleeding according to the International Society of Thrombosis and Hemostasis.

RESULTS

Of 4565 enrolled patients, 4531 were included in the final analysis. The mean age of the patients was 50.5 years, and 72.3% were women. Permanent discontinuation of trial medication was more common with rivaroxaban than with vitamin K antagonist therapy at all visits. In the intention-to-treat analysis, 560 patients in the rivaroxaban group and 446 in the vitamin K antagonist group had a primary-outcome event. Survival curves were nonproportional. The restricted mean survival time was 1599 days in the rivaroxaban group and 1675 days in the vitamin K antagonist group (difference, -76 days; 95% confidence interval [CI], -121 to -31; P<0.001). A higher incidence of death occurred in the rivaroxaban group than in the vitamin K antagonist group (restricted mean survival time, 1608 days vs. 1680 days; difference, -72 days; 95% CI, -117 to -28). No significant between-group difference in the rate of major bleeding was noted.

CONCLUSIONS

Among patients with rheumatic heart disease-associated atrial fibrillation, vitamin K antagonist therapy led to a lower rate of a composite of cardiovascular events or death than rivaroxaban therapy, without a higher rate of bleeding. (Funded by Bayer; INVICTUS ClinicalTrials.gov number, NCT02832544.).

The INVICTUS rheumatic heart disease research program: Rationale, design and baseline characteristics of a randomized trial of rivaroxaban compared to vitamin K antagonists in rheumatic valvular disease and atrial fibrillation

BACKGROUND

Rheumatic heart disease (RHD) is a neglected disease affecting 33 million people, mainly in low and middle income countries. Yet very few large trials or registries have been conducted in this population. The INVICTUS program of research in RHD consists of a randomized-controlled trial (RCT) of 4500 patients comparing rivaroxaban with vitamin K antagonists (VKA) in patients with RHD and atrial fibrillation (AF), a registry of 17,000 patients to document the contemporary clinical course of patients with RHD, including a focused sub-study on pregnant women with RHD within the registry. This paper describes the rationale, design, organization and baseline characteristics of the RCT and a summary of the design of the registry and its sub-study. Patients with RHD and AF are considered to be at high risk of embolic strokes, and oral anticoagulation with VKAs is recommended for stroke prevention. But the quality of anticoagulation with VKA is poor in developing countries. A drug which does not require monitoring, and which is safe and effective for preventing stroke in patients with valvular AF, would fulfill a major unmet need.

METHODS

The INVestIgation of rheumatiC AF Treatment Using VKAs, rivaroxaban or aspirin Studies (INVICTUS-VKA) trial is an international, multicentre, randomized, open-label, parallel group trial, testing whether rivaroxaban 20 mg given once daily is non-inferior (or superior) to VKA in patients with RHD, AF, and an elevated risk of stroke (mitral stenosis with valve area ≤2 cm2, left atrial spontaneous echo-contrast or thrombus, or a CHA2DS2VASc score ≥2). The primary efficacy outcome is a composite of stroke or systemic embolism and the primary safety outcome is the occurrence of major bleeding. The trial has enrolled 4565 patients from 138 sites in 23 countries from Africa, Asia and South America. The Registry plans to enroll an additional 17,000 patients with RHD and document their treatments, and their clinical course for at least 2 years. The pregnancy sub-study will document the clinical course of pregnant women with RHD.

CONCLUSION

INVICTUS is the largest program of clinical research focused on a neglected cardiovascular disease and will provide new information on the clinical course of patients with RHD, and approaches to anticoagulation in those with concomitant AF.

Serum choline esterase and liver function among a group of organophosphorus pesticides sprayers in Egypt

This study was initiated to investigate the long term effect of exposure to organophosphorus pesticides (O.P), with consideration to bilharziasis (an endemic parasitic disease in Egypt, usually associated with liver fibrosis). Serum levels of choline esterase (Ch E), glutamic pyruvic transaminase (SGPT), alkaline phosphatase (Alk. Ph.) and proteins were estimated among 100 (O.P.) sprayers with various duration of exposure (3 to 15 years) and among 60 controls. O.P. sprayers showed significantly higher, SGPT and Alk. Ph. and lower Ch E and serum proteins than the controls. Among sprayers, duration of exposure to O.P. was significantly correlated with their levels of Ch E, SGPT, and Alk. Ph. but not with serum proteins. Compared to other parameters, SGPT seems to be a good indicator of the hepatic effect of long term exposure to O.P. Bilharzial infection did not modify the effect of O.P. pesticides on the above mentioned parameters. Ch E of smoker sprayers was significantly less than that of non smokers. This was attributed to increased absorbtion of O.P. during smoking at work places.

In vivo platelet activity and serum albumin concentration in nephrotic syndrome

To clarify the relationship between serum albumin concentration and in vivo platelet activity in nephrotic syndrome, Beta-thromboglobulin (B-TG) levels and circulating platelet aggregation ratio (PAR) were determined in 25 nephrotic patients. PAR levels were significantly decreased compared with the controls and showed a positive correlation with serum albumin concentrations. The values of B-TG were high in all nephrotic patients and showed an inverse relationship with serum albumin levels. In addition, increased B-TG levels correlated with decreased PAR values. Therefore serum albumin plays a regulatory role in the activity of circulating platelets in the nephrotic syndrome. Prospective longitudinal studies must be done to elucidate the usefulness of platelet inhibitors as a prophylactic therapy of intravascular thrombosis in nephrotic patients.

In vivo platelet activity and lipoprotein patterns in coronary artery disease

In order to determine the effect of hyperlipoproteinemia on the in vivo formation of circulating platelet aggregates (CPA) in patients with coronary artery disease, CPA ratios, lipoprotein pattern, serum cholesterol and triglycerides were determinated in 80 male patients with stable coronary artery disease and hyperlipoproteinemia. Similar studies were performed in 30 male age-matched patients with stable coronary artery disease without hyperlipoproteinemia and 60 male age-matched healthy volunteers; the latter group served as controls. CPA ratios were significantly lowered; i.e. an increase was observed in circulating platelet aggregates in 24 patients without hyperlipoproteinemia as compared with the values in the control group. All the cardiac patients with hyperlipoproteinemia had a significantly lower CPA ratio than the patients without hyperlipoproteinemia. Moreover, the lowering in CPA ratio was more marked among patients with type II a hyperlipoproteinemia than in those with type IV. We think that this in vivo test for platelet function may throw more light on the effect of hyperlipoproteinemia on the in vivo aggregation of circulating platelets in patients with coronary artery disease.