Is contrast administered during left heart catheterization (left heart cath)?

From the Guidelines

Yes, contrast is typically given during a left heart catheterization (cath) to visualize the coronary arteries and left ventricle, with the standard contrast dose ranging from 50-150 mL depending on the complexity of the procedure and patient factors, as recommended by the most recent guidelines 1. The procedure uses iodinated contrast media to identify stenoses or blockages and assess left ventricular function through ventriculography. Before the procedure, patients should be screened for:

• Contrast allergies
• Kidney function, with those having impaired kidney function (eGFR <30 mL/min) potentially receiving lower contrast volumes or alternative imaging approaches, as suggested by the 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention 1. Patients with previous contrast reactions might receive pre-medication with:
• Corticosteroids (like prednisone 50 mg orally 13,7, and 1 hour before)
• Diphenhydramine (50 mg IV/orally) 1 hour before the procedure. Adequate hydration before and after the procedure helps reduce the risk of contrast-induced nephropathy, with the 2012 ACCF/AHA focused update of the guideline for the management of patients with unstable angina/non-ST-elevation myocardial infarction recommending calculation of the contrast volume to creatinine clearance ratio to predict the maximum volume of contrast media that can be given without significantly increasing the risk of contrast-associated nephropathy 1. The use of contrast media is supported by various guidelines, including the 2013 ACCF/AHA guideline for the management of heart failure, which recommends left-heart catheterization or coronary angiography for patients with heart failure and angina, and may be useful for those without angina but with left ventricular dysfunction 1. In terms of minimizing the risk of contrast-induced AKI, efforts should be made to:
• Avoid nephrotoxic agents
• Use adequate hydration before and after the administration of iodinated contrast-agent
• Minimize the volume of contrast media, as recommended by the KDIGO 2024 clinical practice guideline for the evaluation and management of CKD, with commentary by the KDOQI US 1. Overall, the use of contrast media during left heart catheterization is essential for visualizing coronary anatomy and assessing left ventricular function, and its benefits outweigh the risks when proper precautions are taken to minimize the risk of contrast-induced nephropathy.

From the Research

Contrast Agents in Left Heart Catheterization

• The choice of contrast agent in left heart catheterization is crucial, with various options available, including iso-osmolar and low-osmolar agents 2, 3, 4, 5, 6.
• Iodixanol is an iso-osmolar non-ionic dimeric hydrophilic contrast agent that has been shown to have fewer side effects and similar image quality compared to low-osmolar contrast media 2, 3.
• Studies have demonstrated that iodixanol is a safe contrast medium for use in cardioangiography, with good diagnostic efficacy and low adverse events 3.
• The use of iodixanol has been compared to low-osmolar contrast agents, with results indicating that it may be a cost-effective option, especially in patients at high risk of acute kidney injury 5.
• Guidelines for the selective use of contrast agents in the cardiac catheterization laboratory have been proposed, taking into account the patient's risk profile and the specific procedure being performed 4, 6.

Characteristics of Contrast Agents

• Iodixanol has a higher viscosity than monomeric agents and is the only FDA-approved iso-osmolar agent in the United States 2.
• Low-osmolar contrast agents have been shown to produce less perturbation of the homeostatic state, resulting in a lessened incidence of side effects 4.
• Non-ionic agents, such as iodixanol, have been found to be superior to ionic dimers and have a lower risk of thromboembolism 4.

Clinical Implications

• The choice of contrast agent should be based on the individual patient's needs and risk profile, with consideration given to the potential benefits and risks of each agent 4, 6.
• The use of iodixanol may be particularly beneficial in patients at high risk of acute kidney injury or those undergoing complex cardiac procedures 5.