Sluggish flow generally signifies the endothelial vascular lining dysfunction. Normally vessel will dilate when there is requirement of increase flow and constrict when the BP has to maintain. This is called auto regulation. Also sluggish flow denotes higher cholesterol burden in vessel lining.
But as there is no flow limiting luminal obstruction the angioplasty or bypass is not required.
For medication u please visit cardiologist.
Hope this helps.