Why should isosorbide be started in a patient with chest pain on exertion a month after cardiac catheterization with percutaneous coronary intervention (PCI) to the ramus?

From the Guidelines

I strongly recommend starting this patient on isosorbide mononitrate or dinitrate to alleviate chest pain with exertion one month after cardiac catheterization with PCI to the ramus branch, as this will help reduce myocardial oxygen demand and improve blood flow to ischemic areas. The recurrence of angina symptoms after PCI suggests either restenosis at the stent site, incomplete revascularization, or progression of coronary artery disease in other vessels, as noted in the guidelines for the diagnosis and management of patients with stable ischemic heart disease 1.

Key Considerations

• The typical starting dose for isosorbide mononitrate is 30-60mg once daily in the morning, while isosorbide dinitrate is usually started at 10-20mg three times daily with the last dose no later than 7pm.
• Isosorbide, a nitrate medication, works by dilating coronary arteries and reducing preload, which decreases myocardial oxygen demand and improves blood flow to ischemic areas.
• This patient should also be on optimal medical therapy including aspirin, a P2Y12 inhibitor, statin, and possibly a beta-blocker, as recommended by the American College of Cardiology/American Heart Association task force on practice guidelines 1.
• Additionally, the patient should be referred for prompt cardiac evaluation, possibly including stress testing or repeat angiography, as recurrent symptoms after PCI warrant investigation, according to the guidelines for the diagnosis and management of patients with stable ischemic heart disease 1.
• Nitrate tolerance can develop with continuous exposure, so a nitrate-free interval of 10-14 hours daily is recommended if using isosorbide dinitrate.

Management and Follow-Up

• The patient's symptoms and response to treatment should be closely monitored, with adjustments to the treatment plan as needed.
• Regular follow-up appointments with a cardiologist are essential to assess the patient's condition and make any necessary changes to their treatment plan.
• The patient should be educated on the importance of adhering to their medication regimen and attending follow-up appointments to ensure optimal management of their condition.

From the FDA Drug Label

PRECAUTIONS General Nitrate therapy may aggravate the angina caused by hypertrophic cardiomyopathy. Information for Patients Patients should be told that the anti-anginal efficacy of isosorbide dinitrate is strongly related to its dosing regimen, so the prescribed schedule of dosing should be followed carefully.

The patient should be started on isosorbide because nitrate therapy can help with angina pectoris, and the patient is experiencing chest pain with exertion. However, it is crucial to consider the patient's recent cardiac catheterization with PCI to ramus and potential underlying conditions that may be affected by nitrate therapy 2.

• The patient should be closely monitored for signs of severe hypotension and hypotension-induced bradycardia.
• It is also essential to educate the patient on the importance of following the prescribed dosing regimen to maintain the anti-anginal efficacy of isosorbide dinitrate.

From the Research

Chest Pain Management

• Chest pain with exertion a month after cardiac catheterization with PCI to ramus may be a sign of angina pectoris, which is defined as substernal chest pain, pressure, or discomfort that is typically exacerbated by exertion and/or emotional stress 3.
• Angina is a serious morbidity that impedes quality of life and should be treated, with pharmacologic therapy including β-blockers, nitrates, calcium channel blockers, and the late sodium current blocker ranolazine 3.
• Isosorbide, a nitrate, is commonly used to treat angina by relieving chest pain and reducing the frequency of angina attacks, making it a suitable option for managing chest pain with exertion 3.
• The patient's symptoms, such as chest pain with exertion, are consistent with angina, which is often provoked by exertion and relieved by rest 4.

Treatment Options

• Revascularization is indicated in certain high-risk individuals and also has been shown to improve angina, but even after revascularization, a substantial percentage of patients return with recurrent or continued angina, requiring newer and better therapies 3.
• Treatment for refractory angina not amenable to usual pharmacologic therapies or revascularization procedures, includes enhanced external counterpulsation, transmyocardial revascularization, and stem cell therapy 3.
• The choice of treatment should be geared not only to treating the risk factors for atherosclerotic disease and improving survival but should also be aimed at eliminating or reducing the occurrence of angina and improving the ability of patients to be active 3.

Differential Diagnosis

• Chest pain can arise from any structure located in the thoracic cavity, and cardiac causes of chest pain usually have anginal symptoms, while noncardiac causes have a variety of chest pain characteristics 5.
• Diseases that require immediate attention and intervention are myocardial infarction/unstable angina, dissecting aortic aneurysm, pericarditis, pulmonary embolism, pneumothorax, pneumonia, and acute chest syndrome 5.