The single nucleotide polymorphism (SNP) NOS3 894GT located in exon 7 (also known as Glu298Asp, rs1799983) is a genetic marker that has been specifically linked to an increased risk of IHD, hypertension, coronary spasms, and stent re-stenosis [8,14,15]. This evidence concerns the gene NOS3 and myocardial ischemia.