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[Angina due to microvascular pathology]
1Istituto di Cardiologia, Università degli Studi, Milano.
Insights
Syndrome X, a heart condition causing angina with normal coronary arteries, involves issues in the small coronary vessels. Treatments like beta-blockers and calcium-antagonists are effective, leading to good long-term outcomes.
Area of Science:
- Cardiology
- Vascular Biology
- Ischemic Heart Disease
Context:
- Most ischemic heart disease stems from severe coronary atherosclerosis.
- A subset of patients experience angina despite normal coronary arteries and no inducible spasm.
- Coronary microcirculation is identified as the critical factor in these patients.
Purpose:
- To explore the pathophysiology of ischemic heart disease in patients with normal coronary arteries.
- To investigate the role of coronary microcirculation abnormalities in Syndrome X.
- To evaluate treatment efficacy and long-term outcomes.
Summary:
- Syndrome X presents with effort-induced angina, ST-segment changes, and reduced coronary reserve.
- Pathogenesis may involve pre-arteriolar hypersensitivity to vasoconstrictors and reduced vasodilator capacity.
- Treatment with beta-blockers and calcium-antagonists shows effectiveness.
- Long-term follow-up indicates a favorable prognosis with high survival rates and low cardiovascular event incidence.
Impact:
- Highlights the significance of coronary microcirculation in ischemic heart disease.
- Provides insights into the mechanisms underlying Syndrome X.
- Supports the use of specific medications for managing this condition.
- Offers a positive outlook for patients with this form of heart disease.
Abstract:
Most ischemic heart disease in associated with severe coronary atherosclerosis. A small subset of patients, however, had angina pectoris despite angiographically normal coronary arteries and absence of inducible coronary spasm. Coronary microcirculation (i.e. arteries too small to be visualized by current angiographic techniques) has been identified as the weak point of these patients. Small coronary vessel involvement may be due to organic conditions (such as diabetes, vasculitis, systemic collagen-vascular diseases, infectious processes) that act through coronary thrombosis or embolism and related alteration in coronary vasomotion; alternatively, the vascular abnormality appears to be entirely functional (no ultrastructural myocardial changes) such as the case of hypertension, hypertrophic cardiomyopathy and syndrome X. Whatever the cause(s) and mechanism(s) of the small coronary artery involvement, this leads to myocardial ischemia and to the related complications as in classic atherosclerotic heart disease. Syndrome X is characterized by effort-induced angina pectoris, ST-segment changes during exercise testing, negative ergonovine test and reduced coronary reserve. A pre-arteriolar hypersensitivity to vasoconstrictor influences (elicited by cold pressor test or ergonovine) and a reduced vasodilator capacity (unmasked by metabolic and pharmacological studies) have been proposed as potential pathogenetic substrate. This dynamic alteration in vasomotion would answer for both symptoms and signs of myocardial ischemia, that, however, appear to be contemporarily elicitable in a minority of patients. Treatment with beta-blockers and calcium-antagonists has been found to be effective. The long-term follow-up shows favorable outcome with a high survival rate and a low incidence of cardiovascular events.