NEW YORK (Reuters Health) – Intravenous vitamin C before elective percutaneous coronary intervention (PCI) improves microcirculatory reperfusion, new research shows.
This suggests oxidative stress is to blame for the impaired myocardial reperfusion that follows up to 40% of PCI cases, according to lead author Dr. Stefania Basili of the University of Rome “La Sapienza” and colleagues.
In earlier research, Dr. Basili and her associates found lipid peroxidation by-products – evidence of oxidative stress — in coronary sinus blood samples from patients who had PCI, but not from patients who had diagnostic angiography only.
Based on that work, the researchers undertook the current study, in which they randomly assigned 56 patients with stable angina undergoing elective PCI to receive 1 g vitamin C, infused at 16.6 mg/min during the hour before the procedure, or placebo.
In the February issue of JACC: Cardiovascular Interventions, the authors report rates of Thrombolysis in Myocardial Infarction (TIMI) myocardial perfusion grade < 2 were 89% in the placebo group and 86% in the intervention group at baseline. After PCI, however, rates were 32% in the placebo group vs 4% in the vitamin C group (p < 0.01).
Also, 79% of vitamin C patients achieved TIMI perfusion grade 3 – or complete microcirculatory perfusion – compared to 39% of placebo patients (p < 0.01).
To confirm the antioxidant effect of vitamin C, the authors also monitored plasma levels of 8-hydroxy-2-deoxyguanosine and 8-iso-prostaglandin F-2-alpha as markers of oxidative stress and inflammation. At 60 minutes after balloon inflation, levels had increased significantly in the placebo group but had decreased significantly in the patients who received vitamin C.
No patient had post-infusion side effects.
The authors point out that vitamin C has a short half-life, which means that any impact on reperfusion “would probably be a consequence of a short-term effect on arterial dilation.”
But, they add, their data cannot prove a cause and effect relationship, “as no biological markers of arterial dilation were investigated.”
At this point, the researchers conclude, they have established a rationale for further testing of the clinical efficacy of vitamin C infusion.
J Am Coll Cardiol Intv 2010;3:221-229.