The main objective of this proposed study is to examine if oblique projection (20- degrees right anterior oblique (RAO) for right femoral artery access or 20-degree left anterior oblique (LAO) for left femoral artery access) is superior to anterior projection (AP) for femoral artery access in zone 2-4 and thereby resulting in lower risk of access related complications.

The investigators plan to randomize 200 subjects who present for coronary angiography, bypass graph angiography or left heart catheterization via the femoral approach. The investigators will randomly assign them to either oblique projection (20-degree RAO for right femoral artery) or 20-degree LAO (for left femoral artery) versus AP for femoral arterial access in a 1:1 fashion. A trained cardiologist will review the femoral artery angiogram. The investigators will use the scoring system used for the femoral artery access site, as previously reported (10). These predefined locations are as follows: zone 1 denotes femoral artery above the femoral head; zone 2, femoral artery from the superior border of femoral head to the center of the femoral head; zone 3, femoral artery in the center of the femoral head; zone 4, femoral artery from the center of femoral head to the inferior border of the femoral head; and zone 5, femoral artery below the inferior boarder of the femoral head.

The invesigators will use micropuncture access kit for femoral artery access. Micropuncture needle will be advanced to the center of the femoral head and common femoral artery will be punctured guided by fluoroscopy. Those assigned to oblique projection will have fluoroscopic-guided femoral access in RAO 20 degree for right femoral artery and LAO 20 degree for left femoral artery, while those assigned to AP will have femoral artery access in AP 0 degree. For both groups, the investigators will also obtain the other view as a reference to compare results (i.e., in the oblique group, we will save AP and vice versa). If the tip of the micropuncture needle were located in the femoral artery corresponding to the center (zone 3) or bottom third (zone 4) of the femoral head in the 20-degree RAO, 20-degree LAO position or zero-degree AP position, the micropuncture dilator will be advanced into the femoral artery, 0.018" guide wire will be exchanged with a 0.035" guide wire, and a sheath will be placed in the femoral artery, and the femoral angiography will be performed in the 20-degree RAO or 20-degree LAO projection for right and left femoral artery, respectively.

The investigators will also collect data on demographic characteristics including age, race, gender, as well as cardiovascular risk factors such as history of diabetes, hypertension, dyslipidemia, peripheral arterial disease, prior CAD, prior CVA, smoking history, family history of CAD, eGFR. We will also obtain data on medication history to review if they are on antiplatelet or anticoagulants. Those with ipsilateral access within the past 90 days will be excluded.

Inclusion Criteria:

• Patients who are undergoing cardiac catheterization or PCI

Exclusion Criteria:

• Peripheral vascular disease
• Renal failure, Creatinine >2.5 mg/dL
• Hemodynamic instability, acute myocardial infarction
• Heart failure with EF<25%