Gadolinium phosphonates as MR imaging contrast agents: physiologic effects in rabbit hearts

Area of Science:

• Cardiovascular Pharmacology
• Medical Imaging Agents
• Biomedical Engineering

Background:

• New infarct-avid magnetic resonance (MR) imaging agents utilize diphosphonate termini.
• Gadolinium-DTPA-HPDP and HEDP are examples of such agents.
• Understanding their hemodynamic effects is crucial for safe clinical application.

Purpose of the Study:

• To evaluate the hemodynamic effects of diphosphonate-containing MR imaging agents.
• To assess the impact of gadolinium-DTPA-HPDP and HEDP on cardiac function.
• To determine methods for mitigating potential adverse hemodynamic effects.

Main Methods:

• Hemodynamic effects were studied in isolated and intact rabbit hearts.
• Rapid injections of sodium salts of diphosphonates were administered.
• Effects on left ventricular developed pressure, dP/dt, and heart rate were measured.
• Co-administration of calcium ions and slow infusion protocols were tested.

Main Results:

• Rapid injection of diphosphonates reversibly depressed left ventricular pressure and dP/dt.
• In vivo heart rate remained unaffected.
• Hemodynamic depression was prevented by co-administering calcium or using slow infusion.
• Calcium co-administration requirements varied between isolated and intact hearts.

Conclusions:

• Diphosphonate-containing MR imaging agents can cause negative inotropic effects.
• Co-administration of calcium ions or slow infusion can prevent these effects.
• Appropriate measures are necessary for safe use in MR imaging of acute myocardial infarction.