Presence and extent of cardiac computed tomography angiography defined coronary artery disease in patients presenting with syncope

Dizziness in an avid cyclist: an unusual presentation of a common problem

Background

Presyncope and syncope are common presentations with a wide range of differential diagnoses; when it occurs primarily on exertion, a cardiovascular cause is more likely. Structural abnormalities and primary rhythm disturbances are the usual culprits in these patients.

Case summary

A 75-year-old gentleman presented with a history of progressive exertional presyncope. His investigations demonstrated normal cardiac structure, function, and rhythm. He underwent an exercise stress test, which demonstrated a significant reduction in peak blood pressure with equivocal electrocardiogram changes and absence of ischaemic symptoms. In view of his age and gender, a computerized tomography coronary angiogram (CTCA) was organized to exclude obstructive coronary artery disease (CAD). Intriguingly, the CTCA demonstrated a severe proximal left anterior descending (LAD) artery stenosis. This stenosis was confirmed to be functionally significant using invasive coronary physiology and was treated with percutaneous coronary intervention. At follow-up, there was no recurrence of exertional presyncope and the patient was continuing to return to his baseline function.

Conclusion

Presyncope and/or syncope as the sole manifestation of obstructive CAD, in the presence of normal ventricular function and valves, has rarely been reported. Myocardial ischaemia-mediated presyncope and/or syncope may be secondary to numerous mechanisms, which are described in this case report. Revascularization of the functionally significant proximal LAD stenosis resulted in cessation of exertional presyncope in our patient. The long-term outcome of revascularization in patients with presyncope and syncope needs to be further investigated.

ACR Appropriateness Criteria® Syncope

Syncope and presyncope lead to well over one million emergency room visits in the United States each year. Elucidating the cause of syncope or presyncope, which are grouped together given similar etiologies and outcomes, can be exceedingly difficult given the diverse etiologies. This becomes more challenging as some causes, such as vasovagal syncope, are relatively innocuous while others, such as cardiac-related syncope, carry a significant increased risk of death. While the mainstay of syncope and presyncope assessment is a detailed history and physical examination, imaging can play a role in certain situations. In patients where a cardiovascular etiology is suspected based on the appropriate history, physical examination, and ECG findings, resting transthoracic echocardiography is usually considered appropriate for the initial imaging. While no imaging studies are considered usually appropriate when there is a low probability of cardiac or neurologic pathology, chest radiography may be appropriate in certain clinical situations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.