Chest pain with normal coronary angiograms: is the heart innocent or guilty?

Structural and functional abnormality of systemic microvessels in cardiac syndrome X

BACKGROUND AND AIM

Microvascular damage of coronary bed has been considered the main pathogenetic factor of cardiac syndrome X (chest pain, exercise-induced ischemic ST-segment changes and angiographically normal coronary arteries). Previous studies have demonstrated that vascular abnormalities are not confined to the heart, suggesting a peripheral vascular dysfunction. On the hypothesis of a generalized microvascular disturbance in cardiac syndrome X, we performed a morphologic and functional study of systemic microcirculation in patients with syndrome X compared to normal subjects.

METHODS AND RESULTS

Microvessels were evaluated with intravital videocapillaroscopy (VCP) executed in peripheral and conjunctival observation sites which explore micro and paramicrocirculation; biohumoral study included markers of inflammation and of endothelial function, coagulative-fibrinolytic system and lipid metabolism. Videocapillaroscopy showed several morphologic changes (present in high percent of patients with syndrome X and not in controls) and significant quantitative alterations (capillary density, granular flow score, alterations of vessel profile, length of capillary loop branches and of arteriole/venule diameter) which indicated a severe alteration of whole vessel structure and an important rearrangement of microvascular disposition. In a similar way, the humoral study showed some significant changes of endothelial (vWF, ICAM-1, E-sel, PAI-1), inflammatory (C-reactive protein (CRP), fibrinogen) and metabolic factors (HDL-chol) which are commonly associated with inflammatory response.

CONCLUSIONS

We conclude that patients with cardiac syndrome X exhibited some structural and functional alterations of systemic microvasculature; the pattern is similar to that detected in systemic inflammatory diseases and suggests a vascular lesion of inflammatory type. The same changes could be operating also in coronary microvessels of patients with syndrome X.

Cardiac syndrome X: clinical characteristics and left ventricular function. Long-term follow-up study

OBJECTIVES

Our aim was to study the clinical characteristics and evolution of symptoms and left ventricular function in a clinically homogeneous group of patients with syndrome X (angina pectoris, positive exercise test results and normal coronary arteriograms).

BACKGROUND

The syndrome of angina with normal coronary arteriograms is heterogeneous and encompasses different pathogenetic entities. These characteristics may contribute to the existing controversy concerning the cause of syndrome X.

METHODS

We studied 99 patients with syndrome X (78 women, 21 men; mean age +/- SD 48.5 +/- 8 years). All underwent clinical characterization, ambulatory electrocardiographic (ECG) monitoring and echocardiographic assessment of left ventricular function during a follow-up period of 7 +/- 4 years.

RESULTS

The syndrome was more common in women than in men. Of the women, 61.5% were postmenopausal before the onset of chest pain. All 99 patients had exertional angina, and 41 also had rest angina. The average duration of episodes of chest pain was > 10 min in 53% of patients. Sublingual nitrate was effective for relief of pain in 42% of patients. Transient ST segment depression was observed during ambulatory ECG monitoring in 64 patients and myocardial perfusion abnormalities in 22. During the first stage of the exercise test, 32 patients had an increase > 20 mm Hg in systolic blood pressure and showed an earlier onset of ST depression and shorter exercise time than did patients whose blood pressure increased < or = 20%. During follow-up, no deaths or myocardial infarctions occurred, ventricular function was unchanged (shortening fraction 35.4 +/- 4% vs. 35.6 +/- 3%; heart failure developed in only one patient), systemic hypertension occurred in eight patients and conduction disturbances in four. Symptoms lessened in 11 patients, were variable or unchanged in 64 and worsened in 24.

CONCLUSIONS

Syndrome X, as defined in this study, occurs predominantly in postmenopausal women. Patients usually have chest pain typical for angina, but conventional antianginal treatment is not often successful. Myocardial perfusion abnormalities occur in a small proportion of patients. Long-term survival is not adversely affected, and deterioration of cardiac function rarely occurs.