This is a phase 3, multicenter, open-label, blinded, crossover trial in which each participant will undergo a randomized sequence of ASI-02 and agitated saline standard of care (SoC) via a saline contrast transthoracic echocardiogram (TTE) study.

The primary objective is to determine the safety of ASI-02 and its agreement with agitated saline SoC for detection of right-to-left shunt in saline contrast studies utilizing TTE in the intended setting of use (opacifying the right heart). The investigation will be conducted in up to 8 investigational sites in the U.S. and Canada. Participants will receive n=2 ASI-02, n=4 agitated saline SoC injections as part of a single-day imaging session, with the overall duration for study participation of 24 to 48 hours.

Inclusion Criteria:

1. Patient is clinically indicated for a saline contrast TTE study with a suspected right-to-left shunt
2. Patient must be at least 18 years of age inclusive, at the time of signing the informed consent
3. Able to communicate effectively with trial personnel

Exclusion Criteria:

1. Female patients who are pregnant or lactating. All women of child-bearing potential (WOCBP) must have a negative urine pregnancy test at screening regardless of contraceptive use history

2. WOCBP are excluded unless they have been using an adequate and medically approved method of contraception to avoid pregnancy for at least 1 month prior to ASI-02 dose administration

3. Allergy to polysorbate 80 (PS-80)

4. American Society of Anesthesiologists (ASA) physical status classification IV, V, or VI, except that participants with ASA physical status IV due solely to recent suspected transient ischemic attack or cerebrovascular accident are eligible for inclusion

5. Current illness or pathology that in the opinion of the investigator would prevent undergoing investigational product administration due to a significant safety risk to the patient

6. Uncontrolled arterial hypertension (defined as systolic blood pressure ≥ 200 mmHg or diastolic blood pressure ≥ 110 mmHg) or arterial hypotension (defined as systolic blood pressure ≤ 90 mmHg)

7. Unstable cardiovascular status defined as:

   1. myocardial infarction or unstable angina pectoris within 6 months prior to procedure day
   2. symptomatic valvular heart disease or moderate to severe stenotic valvular heart disease
   3. clinically significant congenital heart defects (excluding an atrial septal defect [ASD], patent foramen ovale [PFO], or pulmonary arteriovenous malformation [PAVM])
   4. current uncontrolled cardiac arrhythmias causing clinical symptoms requiring medical intervention or hemodynamic compromise
   5. acute pulmonary embolus or pulmonary infarction
   6. acute myocarditis or pericarditis
   7. acute aortic dissection
   8. untreated atrial fibrillation

8. Any major surgery within 30 days prior to screening

9. Participation in any investigational drug, device, or placebo study within 30 days prior to screening

10. Vulnerable adult participant populations (e.g., incarcerated or cognitively challenged adults)

Due to the potential risks to participant privacy, the possibility of re-identification, concerns about data misuse for commercial purposes, and the potential harm to participants due to sensitive health information, IPD will not be available to other researchers.

This is an open-label study; therefore, blinding procedures are not necessary for site personnel or participants. Blinded assessment of the primary efficacy endpoint will be completed by the core lab.