What imaging studies are recommended for an 82-year-old male with a history of coronary artery bypass grafting and pacemaker placement presenting with dizziness, lightheadedness, and hypotension?

From the Guidelines

For an 82-year-old male with a history of coronary artery bypass grafting and pacemaker placement presenting with dizziness, lightheadedness, and hypotension, the most appropriate initial imaging study is an echocardiogram, as recommended by the European Association of Cardiovascular Imaging 1. This recommendation is based on the patient's presentation with hypotension, which is a key indicator for the use of echocardiography in emergency settings, as outlined in the European Heart Journal study 1. The echocardiogram will help evaluate cardiac structure and function, including valve function, wall motion abnormalities, and ejection fraction, which are crucial in assessing the cause of hypotension in this patient.

Some key points to consider in the evaluation of this patient include:

• The patient's history of coronary artery bypass grafting and pacemaker placement, which increases the risk of cardiac complications
• The presentation with dizziness and lightheadedness, which may be indicative of orthostatic hypotension or other cardiac issues
• The importance of evaluating pacemaker function and assessing for arrhythmias, which can be done using an electrocardiogram (ECG)
• The potential for carotid stenosis as a cause of dizziness, which may be assessed using carotid ultrasound

Given the patient's symptoms and medical history, the following imaging studies are recommended:

• Echocardiogram to evaluate cardiac structure and function
• Electrocardiogram (ECG) to evaluate pacemaker function and assess for arrhythmias
• Chest X-ray to verify pacemaker lead position and assess for pulmonary congestion or other cardiopulmonary abnormalities
• Carotid ultrasound to assess for carotid stenosis as a cause of dizziness

It is essential to note that MRI is generally contraindicated in patients with pacemakers unless the device is MRI-compatible. If pacemaker malfunction is suspected, a pacemaker interrogation should be performed immediately. Laboratory tests, including complete blood count, electrolytes, renal function tests, and cardiac enzymes, should accompany these imaging studies to rule out other potential causes of the patient's symptoms.

From the Research

Imaging Recommendations

The patient's symptoms of dizziness, lightheadedness, and hypotension, particularly with a history of coronary artery bypass grafting and pacemaker placement, suggest the possibility of coronary-subclavian steal syndrome. The following imaging studies are recommended:

• Computed Tomography Angiography (CTA) of the chest to evaluate the subclavian arteries and the coronary artery bypass grafts 2
• Subclavian angiography to assess the severity of subclavian artery stenosis or occlusion 2
• Doppler ultrasound to evaluate blood flow in the subclavian and vertebral arteries 3
• Aortography to demonstrate proximal left subclavian artery occlusion 4
• Nuclear stress testing to assess for areas of ischemia 2
• Coronary angiography to evaluate the native coronary arteries and the bypass grafts 2, 5

Rationale

The coronary-subclavian steal syndrome is a rare complication of coronary artery bypass grafting surgery, characterized by retrograde flow from the left internal mammary artery graft to the left subclavian artery due to a proximal left subclavian artery stenosis or occlusion 6, 2, 5. The recommended imaging studies will help to diagnose and assess the severity of the condition, guiding further management and treatment.

Diagnostic Considerations

The diagnosis of coronary-subclavian steal syndrome requires a high index of suspicion, particularly in patients with a history of coronary artery bypass grafting and symptoms of cardiac ischemia or arm claudication 6, 2, 5. The imaging studies recommended will help to confirm the diagnosis and guide further management.