In recent years, it has become apparent that coronary microvascular dysfunction plays a pivotal pathogenic role in angina pectoris. Functional and structural mechanisms can affect the physiological function of the coronary microvasculature and lead to myocardial ischemia in people without coronary atheromatous disease and also in individuals with obstructive coronary artery disease. Abnormal dilatory responses of the coronary microvessels, coronary microvascular spasm, and extravascular compressive forces have been identified as pathogenic mechanisms in both chronic and acute forms of ischemic heart disease. The condition characterized by anginal symptoms and evidence of myocardial ischemia triggered by coronary microvascular dysfunction, in the absence of obstructive coronary disease, is known as microvascular angina. The concept of microvascular angina, however, may extend further to include patients with obstructive coronary artery disease and individuals with angina after coronary revascularization or heart transplantation because coronary microvascular dysfunction contributes to myocardial ischemia in many such patients. Patients with microvascular angina constitute a sizeable proportion of all cases of stable angina undergoing diagnostic coronary angiography and of those with persisting angina after successful coronary revascularization. Coronary microvascular dysfunction is also often responsible for angina in individuals with cardiomyopathy and heart valve disease as well as acute coronary syndrome cases such as Takotsubo syndrome and myocardial infarction with no obstructive coronary artery disease. Patients with stable microvascular angina present typically with effort or rest chest pain and a reduced coronary flow reserve or microvascular spasm. This condition, which affects women and men, can markedly impair quality of life and prognosis and represents a substantial cost burden to healthcare systems and individuals alike. In recent years, progress in the diagnosis of myocardial ischemia and the use of tests to investigate functional and structural causes for a reduced coronary flow reserve and microvascular spasm have allowed the identification of an increased number of cases of microvascular angina in everyday clinical practice. Although some of the available anti-anginal drugs may be helpful, treatment of coronary microvascular dysfunction remains a major challenge. The present article discusses the fundamental role that coronary microvascular dysfunction plays in the pathogenesis of ischemic heart disease, the clinical characteristics of patients presenting with microvascular angina, and possible diagnostic and therapeutic strategies.

Objectives— Thiazolidinediones, such as rosiglitazone, have been shown to retard atherosclerosis disease progression in diabetic subjects. These agents may have anti-atherosclerotic effects through direct inhibition of inflammatory processes in the vessel wall, and so their benefit may extend to patients with atherosclerotic disease, even in the absence of diabetes. In this study, we assessed the effect of rosiglitazone on common carotid intima-media thickness (IMT) progression in nondiabetic coronary artery disease (CAD) patients. Methods and Results— Consecutive subjects (n=92) with clinically stable, angiographically documented CAD and without diabetes mellitus were randomized in a double-blind manner to receive placebo or rosiglitazone for 48 weeks. They received single-dose placebo and rosiglitazone 4 mg daily for the initial 8 weeks, and the doses were doubled for the remainder of the study. Common carotid IMT together with fasting glucose, insulin, and lipid profile were measured at baseline and repeated after 24 and 48 weeks. Rosiglitazone-treated patients showed reduced IMT progression compared with the placebo group, −0.012 mm/48 weeks versus 0.031 mm/48 weeks ( P =0.03). Rosiglitazone treatment significantly reduced insulin resistance, estimated by homeostasis model of insulin resistance index, compared with placebo ( P =0.01). Conclusions— Rosiglitazone reduces common carotid IMT progression in nondiabetic CAD patients, and insulin-sensitization may be one contributory mechanism.

Background— Both endothelial cell activation and macrophage activation play a significant role in atherogenesis and atheromatous plaque vulnerability and may determine rapid coronary artery disease (CAD) progression. We sought to assess the association between serum inflammatory markers and rapid CAD progression in patients with chronic stable angina pectoris. Methods and Results— We studied 124 chronic stable angina pectoris patients (84 men; mean age, 61±10 years) who were on a waiting list for coronary angioplasty for a mean time of 4.8±2.4 months. CAD progression was defined as ≥10% diameter reduction of a pre-existing stenosis ≥50%, ≥30% diameter reduction of a stenosis <50%, development of a new stenosis ≥30% in a previously normal segment, or progression of any stenosis to total occlusion. CAD progression occurred in 35 patients (28%). After adjustment with binary logistic regression, neopterin ( P <0.001), high-sensitivity C-reactive protein ( P =0.017), matrix metalloproteinase-9 ( P =0.002), soluble intercellular adhesion molecule 1 ( P <0.001), and previous history of unstable angina ( P =0.01) were independent predictors of rapid CAD progression. The association between rapid disease progression and inflammatory markers remained significant even when presence of complex lesions was introduced into the multivariate model. Conclusions— Rapid CAD progression in patients with stable angina pectoris is associated with increased C-reactive protein levels and raised concentrations of biochemical markers of endothelial and macrophage activation.

Background: Diagnosis of cardiac ischaemia in patients attending emergency departments (ED) with symptoms of acute coronary syndromes is often difficult. Cardiac troponin (cTn) is sensitive and specific for the detection of myocardial damage but may not rise during reversible myocardial ischaemia. Ischemia Modified Albumin (IMA) has recently been shown to be a sensitive and early biochemical marker of ischaemia. Methods and Results: This study evaluated IMA in conjunction with ECG and cTn in 208 patients presenting to the ED within three hours of acute chest pain. At presentation, a 12-lead ECG was recorded and blood taken for IMA and cardiac troponin T (cTnT). Patients underwent standardised triage, diagnostic procedures, and treatment. Results of IMA, ECG, and cTnT, alone and in combination, were correlated with final diagnoses of non-ischaemic chest pain, unstable angina, ST segment elevation, and non-ST segment elevation myocardial infarction. In the whole patient group, sensitivity of IMA at presentation for an ischaemic origin of chest pain was 82%, compared with 45% of ECG and 20% of cTnT. IMA used together with cTnT or ECG, had a sensitivity of 90% and 92%, respectively. All three tests combined identified 95% of patients whose chest pain was attributable to ischaemic heart disease. In patients with unstable angina, sensitivity of IMA used alone was equivalent to that of IMA and ECG combined. Conclusions: IMA is highly sensitive for the diagnosis of myocardial ischaemia in patients presenting with symptoms of acute chest pain.

Far more extensive than the epicardial coronary vasculature that can be visualized angiographically is the coronary microcirculation, which foregoes routine imaging. Probably due to the lack of techniques able to provide tangible evidence of its crucial role, the clinical importance of coronary microvascular dysfunction is not fully appreciated. However, evidence gathered over the last several decades indicates that both functional and structural abnormalities of the coronary microvasculature can lead to myocardial ischaemia, often comparable with that caused by obstructive coronary artery disease. Indeed, a marked increase in coronary microvascular resistance can impair coronary blood flow and trigger angina pectoris, ischaemic ECG shifts, and myocardial perfusion defects, and lead to left ventricular dysfunction in patients who otherwise have patent epicardial coronary arteries. This condition—often referred to as ‘chest pain with normal coronary arteries’ or ‘cardiac syndrome X’—encompasses several pathogenic mechanisms involving the coronary microcirculation. Of importance, coronary microvascular dysfunction can occur in conjunction with several other cardiac disease processes. In this article, we review the pathogenic mechanisms leading to coronary microvascular dysfunction and its diagnostic assessment, as well as the different clinical presentations and prognostic implications of microvascular angina. As such, this review aims to remove at least some of the mystery surrounding the notion of coronary microvascular dysfunction and to show why it represents a true clinical entity.

Background Proinflammatory cytokines play a role in acute coronary events. However, the potential role of antiinflammatory cytokines in the modulation of the atherosclerotic process remains unknown. Interleukin (IL)-10, which is expressed in human atherosclerotic plaques, has potent deactivating properties in macrophages and T cells. The aim of this study was to assess whether serum concentrations of IL-10 differed between patients with unstable and stable angina pectoris. Methods and Results A total of 95 patients with angina pectoris and angiographically documented coronary artery disease were studied. Of these, 50 patients had chronic stable angina (with stable symptoms over 3 months), and 45 patients had Braunwald class IIIB unstable angina with ST-segment changes. Serum IL-10 and IL-6 concentrations were measured on admission using commercially available immunoassays. Serum IL-10 concentrations were lower in unstable angina patients compared with those who had chronic stable angina (28.4 versus 14.0 pg/mL; 95% CI, 9.8 to 19.0; P <0.0001), even after adjustment for variables that were significantly different on univariate analysis. IL-6 concentrations were higher in the unstable angina group (20.9 versus 11.4 pg/mL; 95% CI, 1.0 to 12.6; P =0.04). Conclusions Patients with unstable angina had significantly lower serum IL-10 concentrations than did patients with chronic stable angina. This important finding is in keeping with previous data from animal model studies that suggest that IL-10 has a protective role in atherosclerosis.