Contraindications Relative contraindications to PCI include Coagulopathy A single diseased vessel providing all perfusion to the myocardium Critical left main coronary stenosis without collateral flow from a native vessel or previous bypass graft to the left anterior descending artery Diffusely diseased vessels without focal stenoses Hypercoagulable states Lack of cardiac surgical support Stenosis < 50% Total occlusion of a coronary artery Although lack of cardiac surgical support is sometimes considered an absolute contraindication to PCI, many experts advocate that when revascularization is required urgently in STEMI, experienced operators in approved catheterization laboratories should proceed with PCI even if surgical backup is not available.