• Participants With Successful Common Femoral Artery Cannulation, as Determined by Femoral Angiography [ Time Frame: Immediately, during procedure. ] [ Designated as safety issue: Yes ]

  Femoral angiography was performed in 490 control patients and 499 ultrasound patients. In 11 control and 4 ultrasound patients, femoral angiography was either not performed or was inadequate for analysis. These patients were excluded from the primary outcome analysis but included for other analyses.

  Successful common femoral artery cannulation was defined as sheath insertion above the bifurcation of the common femoral artery and below the origin of the inferior epigastric artery. Unsuccessful sheath insertion was defined as sheath insertion outside of these markers.

  
  

• Time to Successful Sheath Insertion. [ Time Frame: Immediate ] [ Designated as safety issue: No ]

  Time was measured from first fluoroscopy of the femoral head (control group), or first application of the ultrasound probe (ultrasound group), until successful sheath insertion.

  Time was not recorded for 1 control patient, and 1 ultrasound patient, these patients were excluded from this analysis but included for other analyses.

  
  
• Number of Patients With Accidental Femoral Venipunctures. [ Time Frame: Immediate ] [ Designated as safety issue: Yes ]

  Number of patients with any femoral venipunctures where an insertion was not intended, i.e. excluding patients with planned right heart catheterization. Multiple accidental venipunctures were not double counted.

  Number of attempts and venipunctures were not recorded in 1 control and 1 ultrasound patient, so the denominator is 500 control patients and 502 ultrasound patients.

  
  
• Number of Participants With Vascular Complications [ Time Frame: Immediate and up to 1 month after procedure. ] [ Designated as safety issue: Yes ]

  Vascular complications were defined as vessel thrombosis, dissection, blood transfusion, hematoma > 5cm diameter, unexplained bleeding with a drop in Hgb >4 g/dL, or access site bleeding with drop in Hgb >3 g/dL.

  Outcome was assessed by chart review, and clinical or telephone followup at 30 days. Medical records were adjudicated by a blinded independent review committee.

  
  

Cardiac catheterization is conventionally performed with femoral arterial access using a combination of arterial pulse palpation, anatomical landmarks, and fluoroscopic landmarks to guide needle insertion. Vascular access complications including hematoma formation, retroperitoneal bleeding, and arterial dissection are the most common types of adverse events associated with cardiac catheterization, and have been associated with insertions above and below the level of the common femoral artery. Real-time ultrasound assistance for central venous catheter placement has been proven in multiple studies to reduce complications, and has been recommended by the Agency for Healthcare Research and Quality as a "Top 11 Highly Proven" patient safety practice. This recommendation has not yet been extended to arterial access, due to a lack of studies to date. However, ultrasound assistance is licensed for and commonly utilized for arterial access, especially in difficult patients.

In a pilot study of 71 procedures performed by the lead researcher, ultrasound guidance was associated with an improved 1st pass success rate (83% vs 47%, p=0.002), reduced risk of accidental venipunctures (0% vs 25%, p=0.002), and greater overall success in common femoral artery cannulation (89% vs 69%, p=0.048) as compared with the fluoroscopic control.

This study is a multicenter prospective randomized trial to generalize the above findings with more patients studied, a larger number of operators, and across several centers. Similar to the previous study, the ultrasound will be used real-time to visualize the femoral vein, femoral artery, and needle tract as the needle is inserted, to guide the needle towards the appropriate location in the artery. The time for insertion, number of passes, complications, and position of the insertion catheter on the femoral angiogram will be analyzed in the setting of patient factors including age, body mass index, and presence of peripheral vascular disease.