Medications which thin the blood to reduce the risk of blood clots may also be needed. In the case of serious disease surgery may be required to repair or replace the heart valves. This is often not available in low-income settings, or when it is available the costs may be too high if not covered as part of national health plans, putting families under increased financial strain. Since rheumatic heart disease results from rheumatic fever, an important strategy is to prevent rheumatic fever from occurring. Treatment of strep throat with appropriate antibiotics will prevent rheumatic fever.