From the Guidelines
Regadenoson (Lexiscan) can be used with caution in patients with severely impaired left ventricular function, including those with an LVEF of 30%. While it is generally considered safer than older vasodilator stress agents like adenosine or dipyridamole in patients with left ventricular dysfunction, close monitoring is essential during the test. The standard dose remains 0.4 mg administered as a rapid intravenous injection over approximately 10 seconds, followed by a saline flush. For patients with severe left ventricular dysfunction, the medical team should be prepared to manage potential adverse effects, including having aminophylline readily available to reverse regadenoson's effects if necessary. Regadenoson is preferred in this population because it causes less reduction in blood pressure and has a more selective A2A adenosine receptor stimulation compared to other vasodilators, resulting in less bronchospasm and less severe hypotension. However, the stress test should be performed in a setting with appropriate cardiac monitoring and resuscitation equipment, with particular attention to hemodynamic parameters throughout the procedure. The benefit of detecting significant coronary artery disease in these high-risk patients often outweighs the risks of the procedure when proper precautions are taken, as supported by guidelines such as those from the American College of Cardiology Foundation/American Heart Association 1.
Some key points to consider when using regadenoson in patients with severely impaired left ventricular function include:
- The importance of close monitoring during the test
- The need for appropriate cardiac monitoring and resuscitation equipment
- The potential for adverse effects and the need for preparedness to manage them
- The benefits of detecting significant coronary artery disease in high-risk patients
It's also important to note that regadenoson has a more favorable side-effect profile compared to other vasodilator stress agents, making it a preferred choice for patients with left ventricular dysfunction, as mentioned in guidelines such as the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery 1.
Overall, the use of regadenoson in patients with severely impaired left ventricular function requires careful consideration and preparation, but can be a valuable tool for detecting significant coronary artery disease in high-risk patients.
From the Research
Safety of Lexiscan in Patients with Severely Impaired Left Ventricular Function
- The safety of Lexiscan (regadenoson) in patients with severely impaired left ventricular function, specifically a left ventricular ejection fraction (LVEF) of 30%, is a concern due to the potential for adverse effects 2.
- A case report published in 2020 described a patient who developed takotsubo cardiomyopathy after undergoing a Lexiscan stress test, with a significantly reduced LVEF of 25% and 30% on subsequent tests 2.
- However, other studies have shown that regadenoson can be safe and effective in patients with heart failure and reduced ejection fraction (HFrEF), with no significant adverse events reported 3.
- A study published in 2016 found that regadenoson stress testing was well tolerated in patients with LVEF <40%, with no significant differences in adverse effects compared to patients with LVEF ≥40% 4.
Comparison with Other Stress Agents
- A study published in 2015 compared the safety of adenosine and regadenoson in patients undergoing outpatient cardiac stress testing, and found that regadenoson was associated with a higher incidence of adverse effects, including arrhythmia, dyspnea, and headache 5.
- However, another study published in 2019 found that transcatheter aortic valve replacement (TAVR) was associated with similar clinical outcomes in patients with low-flow, low-gradient aortic stenosis and LVEF <30% compared to those with LVEF 30-40% 6.