Can I administer Glyceryl Trinitrate (GTN) intraoperatively to a patient with Mitral Regurgitation (MR)?

From the Guidelines

Yes, you can administer glyceryl trinitrate (GTN) intraoperatively for a patient with mitral regurgitation (MR), but careful consideration is necessary. GTN is typically given as an IV infusion starting at 0.5-1 mcg/kg/min, titrated to effect up to 10 mcg/kg/min, or as sublingual tablets (0.3-0.6 mg) for acute management. For patients with MR, GTN can be beneficial as it reduces preload and afterload, potentially decreasing regurgitant volume and improving forward cardiac output 1. However, dosing should be conservative and closely monitored as excessive preload reduction may worsen hemodynamics in patients who are preload-dependent.

Key Considerations

• Continuous hemodynamic monitoring is essential during administration, including blood pressure, heart rate, and if available, pulmonary artery pressures.
• Be prepared to reduce or discontinue GTN if hypotension develops, and have volume support readily available.
• The vasodilatory effects of GTN work by releasing nitric oxide, causing smooth muscle relaxation in blood vessels, which can be particularly helpful in managing hypertension or myocardial ischemia that might exacerbate MR during surgery 1.
• Patients with severe MR may require careful management to optimize forward cardiac output and reduce regurgitant volume, and GTN can be a useful adjunct in this setting.

Monitoring and Management

• Intraoperative and postoperative hemodynamic monitoring is recommended for patients with severe MR undergoing noncardiac surgery 1.
• Patients with MR should be monitored with invasive hemodynamics and echocardiography, and admitted postoperatively to an intensive care unit setting when undergoing surgical procedures with elevated risk 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION NOT FOR DIRECT INTRAVENOUS INJECTION NITROGLYCERIN INJECTION IS A CONCENTRATED, POTENT DRUG WHICH MUST BE DILUTED IN DEXTROSE (5%) INJECTION OR SODIUM CHLORIDE (0. 9%) INJECTION PRIOR TO ITS INFUSION.

The FDA drug label does not answer the question.

From the Research

Intraoperative GTN Administration for Patients with MR

• The use of intraoperative glyceryl trinitrate (GTN) for patients with mitral regurgitation (MR) is a topic of interest in the field of anesthesiology 2.
• Studies have shown that GTN, also known as nitroglycerin, can decrease mitral regurgitant area substantially and almost abolish mitral regurgitation in patients with decompensated chronic heart failure and functional mitral regurgitation 3.
• The administration of GTN has been found to increase forward aortic flow and reduce regurgitant mitral volume, which can be beneficial for patients with MR undergoing noncardiac surgery 3.
• However, the potential benefits of GTN are limited by a decreased vasodilatory response in patients with heart failure, requiring active titration of the drug and the use of high doses 4.
• Additionally, the initial beneficial hemodynamic effect achieved with GTN is associated with neurohumoral activation and limited by an early development of nitrate tolerance 4.

Considerations for Intraoperative GTN Administration

• The decision to administer GTN intraoperatively should be based on individual patient factors, including the severity of MR and the presence of other comorbidities 2, 5.
• Anesthetic management, including preoperative risk evaluation, anesthetic selection, hemodynamic goals, and intraoperative monitoring, is crucial for patients with MR undergoing noncardiac surgery 2.
• The use of GTN should be carefully considered in the context of the patient's overall clinical picture, including the potential benefits and limitations of the drug 3, 4.