Atherothrombotic complications are frequently seen in patients undergoing heart transplantation. These patients have high plasma total homocysteine concentrations associated with lower folate and vitamin B6 levels. The relation between these metabolic abnormalities and the development of vascular complications, however, remains unclear. Fasting plasma total homocysteine, folate, vitamin B12, vitamin B6, and creatinine were measured in 160 cardiac transplant recipients who were followed for a mean duration of 28 ± 9 months after blood draw (mean 59 ± 28 months after transplant). Cardiovascular events and causes of mortality were determined and Cox proportional-hazards regression analysis was used to identify the independent predictors for cardiovascular events and mortality. Twenty-five patients developed cardiovascular events and 17 died (11 cardiovascular deaths). Mean ± SD total homocysteine value was 18.4 ± 8.5 (range 4.3 to 63.5 μmol/L). Hyperhomocysteinemia (≥15 μmol/L) was seen in 99 patients (62%). Levels were no different in patients with or without cardiovascular complications/death (16.8 ± 6.2 vs 18.9 ± 9 μmol/L, p = 0.4). However, vitamin B6 deficiency was seen in 21% of recipients with and in 9% without cardiovascular complications/death (p = 0.05). The relative risk for cardiovascular events, including cardiovascular death, increased 2.7 times (confidence interval 1.2 to 5.9) for B6 levels ≤20 nmol/L compared with those with normal B6 levels (p = 0.02). Thus, hyperhomocysteinemia is common in transplant recipients but may have no causal role in the atherothrombotic vascular complications of transplantation. Deficiency of vitamin B6, however, may predict adverse outcomes, suggesting a possible role for supplementation with this vitamin.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine