What are the risks associated with an echocardiogram (echo) with bubble study?

Risks Associated with Echocardiogram with Bubble Study

Echocardiogram with bubble study is an extremely safe procedure with a very low risk profile, with serious adverse events occurring in only 0.005% to 0.015% of cases, placing it in the lowest risk category for contrast procedures. 1

Safety Profile of Contrast Agents Used in Bubble Studies

• Extensive safety data from over 10 years of use in millions of patients has established the excellent safety profile of contrast echocardiography 1
• Ultrasound contrast agents fall into the "low risk" category for severe anaphylaxis, with an incidence of only 0.005%-0.015%, comparable to analgesics, antibiotics, and MRI contrast media 1
• Large retrospective analyses of 18,000 patients showed no significant difference in mortality between patients who received contrast versus those who did not, despite contrast group patients having higher baseline risk 1
• A propensity-matched study of >16,000 patients actually demonstrated lower mortality at 48 hours (1.70% vs. 2.50%) and during hospital stay (14.85% vs. 15.66%) in patients receiving contrast echocardiography compared to non-contrast studies 1

Specific Adverse Events

• Adverse events are rare, occurring in approximately 1 in 1,000 to 1 in 10,000 patients 1
• Most adverse reactions are mild and transient, including:
  • Headache 1
  • Nausea 1
  • Dizziness 1
  • Taste disturbances 1
  • Paresthesia 1
  • Chest discomfort 1
  • Injection site reactions 1
• These mild reactions typically resolve without treatment beyond patient reassurance 1
• Serious anaphylactic reactions are extremely rare but may occur, requiring treatment similar to other immunoglobulin E-mediated allergic reactions 1

Contraindications

• The only absolute contraindications for ultrasound contrast agents are:
  • Known hypersensitivity to the specific contrast agent 1
  • Previously, significant intracardiac shunts were considered a contraindication, but this restriction has been questioned and the FDA has lifted this contraindication for Definity (Luminity in Europe) 1
• Intracoronary administration is not approved and considered contraindicated, although it has been performed without complications in thousands of patients with hypertrophic cardiomyopathy undergoing septal ablation 1

Procedural Complications

• Complications specific to the bubble study procedure itself are exceedingly rare
• One study of 924 patients found only 1 patient (0.1%) suffered a TIA as a complication of a bubble study 2
• For transthoracic echocardiography with bubble study, there are virtually no procedural risks beyond those associated with the contrast agent itself 3, 4

Management of Adverse Events

• Echocardiography laboratories should have protocols in place to manage potential adverse events 1
• Treatment for severe reactions includes:
  • IV antihistamines 1
  • Steroids 1
  • Small doses of epinephrine for symptomatic hypotension 1
• Early diagnosis and treatment can positively affect the severity and course of anaphylactic reactions 1

Clinical Perspective

• The diagnostic benefits of bubble studies typically far outweigh the minimal risks 1, 3
• Bubble studies are essential for detecting intracardiac shunts like patent foramen ovale, which may be crucial in evaluating cryptogenic stroke patients 3, 4
• Transesophageal echocardiography (TEE) with bubble study provides higher sensitivity (51% vs. 32%) for detecting shunts compared to transthoracic echocardiography (TTE) 3
• The procedure's safety profile is so favorable that the European Association of Cardiovascular Imaging recommends its use whenever two or more contiguous myocardial segments are not well visualized 4

In conclusion, echocardiogram with bubble study carries minimal risk with significant diagnostic benefits, making it an extremely safe and valuable diagnostic tool in appropriate clinical scenarios.