Patients With Syndrome X Have Normal Transmural Myocardial Perfusion and Oxygenation

Abstract

Background-The pathophysiology of chest pain in patients with cardiac syndrome X remains controversial. Advances in perfusion imaging with cardiovascular magnetic resonance (CMR) now enable absolute quantification of regional myocardial blood flow (MBF). Furthermore, blood oxygen level-dependent (BOLD) or oxygenation-sensitive CMR provides the unprecedented capability to assess regional myocardial oxygenation. We hypothesized that the combined assessment of regional perfusion and oxygenation with CMR could clarify whether patients with syndrome X show evidence of myocardial ischemia (reduced perfusion and oxygenation) during vasodilator stress compared with normal volunteers. Methods and Results-Eighteen patients with syndrome X (chest pain, abnormal exercise treadmill test, normal coronary angiogram without other causes of microvascular dysfunction) and 14 controls underwent CMR scanning at 3 T. Myocardial function, scar, perfusion (2-3 short-axis slices), and oxygenation were assessed. Absolute MBF was measured during adenosine stress (140 g/kg per minute) and at rest by model-independent deconvolution. For oxygenation, using a T2-prepared BOLD sequence, signal intensity was measured at adenosine stress and rest in the slice matched to the midventricular slice of the perfusion scan. There were no significant differences in MBF at stress (

Ischemia and No Obstructive Coronary Artery Disease (INOCA): What Is the Risk?

“…Previously, the term CSX was used to refer to patients with no obstructive CAD but did not require proof of ischemia23, 24 and also included patients with acute coronary syndromes and no obstructive CAD 22, 23, 25. Advanced evaluation can now identify CMD or macrovascular dysfunction by invasive or noninvasive measurements of CFR in a majority of these patients,12, 26 while coronary atherosclerosis and better characterization of plaques can be assessed by intravascular ultrasound, optical coherence tomography, or computed coronary tomography angiography when not evident or appreciated at invasive coronary angiography 27, 28, 29.…”

The head says yes but the heart says no: what is non-cardiac chest pain and how is it managed?

“…Syndrome X was more common in women while NCCP is seen approximately equally in both sexes probably because apparently abnormal ST segment changes are more likely in women. There may be evidence of microvascular dysfunction,36 but stress echocardiography is normal and evidence for subendocardial ischaemia on cardiac magnetic resonance (CMR) is contradictory 37 38. It is impossible to summarise a huge literature within this focused review, but recent papers stress the concept of heightened pain perception39–41 which may be affected by psychological factors41 42 and which may respond to psychological treatments 23 40 41.…”

Cardiac Mri Assessment of Myocardial Perfusion

“…CMR quantitative perfusion data is now available in various populations (syndrome X) [27], various myocardial regions (subepicardium vs subendocardium) [28], using different techniques (manual vs automatic) [29], and with different vasodilator agents (adenosine and regadenoson [30]).…”