Effect of Left Ventricular Systolic Dysfunction on Response to Warfarin

Area of Science:

• Cardiology
• Pharmacology
• Clinical Medicine

Background:

• Chronic warfarin therapy is common for patients with comorbidities like heart failure.
• Reduced warfarin dose requirements and over-anticoagulation risk are noted in decompensated heart failure.
• The specific impact of left ventricular systolic dysfunction (LVSD) on warfarin response is not well-established.

Purpose of the Study:

• To evaluate the influence of LVSD on warfarin dose requirements.
• To assess the effect of LVSD on anticoagulation control (time in therapeutic range).
• To determine the risk of over-anticoagulation and major hemorrhage in patients with LVSD.

Main Methods:

• Prospective cohort study of 1,354 patients on chronic warfarin therapy.
• Patients were categorized based on the presence or absence of LVSD (left ventricular ejection fraction <40%).
• Multivariate regression analyses were used to assess warfarin dose, anticoagulation control, and hemorrhage risk.

Main Results:

• Patients with LVSD required an 11% lower warfarin dose (p <0.001).
• Anticoagulation control (percent time in target range) was similar between groups (51% vs 53%, p = 0.15).
• LVSD did not significantly increase the risk of over-anticoagulation (HR 1.01) or major hemorrhage (HR 1.11).

Conclusions:

• LVSD is associated with a reduced warfarin dose requirement.
• LVSD does not appear to significantly alter anticoagulation control or major bleeding risk.
• Further research is needed to determine if incorporating LVSD into warfarin dosing algorithms improves patient outcomes.