In designing any causal study, steps must be taken to address both internal and external threats its validity. Researchers tend focus primarily on dealing with However, once they have conducted an internally valid analysis, that analysis yields established set of findings for the specific case in question. As future usefulness result, however, what matters is degree this paper we provide a form...

a 73-year-old woman who had undergone coronary artery bypass grafting for coronary artery stenosis six years ago, presented with right lower extremity claudication. angiography revealed right external artery stenosis. elective external iliac ptca was performed complicated with simultaneous external iliac artery and vein rupture that was an exceedingly rare event. retroperitoneal laparotomy with...