Long-term (5 year) effects of transient (silent) ischaemia on left ventricular systolic function in stable angina. Clinical and radionuclide study

Clinical outcomes in patients with primary stable microvascular angina: is the jury still out?

Several studies have demonstrated that angina chest pain in presence of normal or near normal coronary arteries (NCAs) is mainly related to coronary microvascular dysfunction (CMD). However, controversial findings exist about clinical outcome of these patients. In this article, we critically review characteristics and results of the main clinical studies reporting clinical outcome of stable patients with angina chest pain and non-obstructive coronary artery disease (NO-CAD). Published data indicate that clinical outcomes of these patients are heterogeneous, but those with strict criteria for primary stable microvascular angina (MVA, i.e. typical angina with NCAs mainly related to efforts) do not appear to have an increased mortality or risk of major coronary events. A major determinant of outcome in patients with MVA and NO-CAD seems instead related to non-critical atherosclerotic disease, the presence of which should suggest a more aggressive management of cardiovascular risk factors and preventive management. Future studies should assess whether CMD may have a relevant prognostic role in the latter clinical context and/or in other clinical settings of NO-CAD different from primary stable MVA.

[Prevalence and prognostic significance of silent myocardial ischemia in patients after myocardial infarction]

BACKGROUND/AIM

Silent myocardial ischemia (MI) can be detected in subjects with any symptoms, in patients after myocardial infarction and in coronary patients who have episodes of symptomatic, as well as of silent MI. This study was carried out to evaluate the frequency, characteristics and prognostic significance of silent MI detected in stress echocardiography test in patients after myocardial infarction.

METHODS

In 210 patients within three months after myocardial infarction exercise test was performed. In those patients with ischemic ST depression on exercise electrocardiogram, in order to confirm MI stress echocardiography was additionally performed. To assess the incidence of major cariovascular events, all the patients were followed at least five years after the first myocardial infraction.

RESULTS

Out of 210 patients 88 (42%) had ischemic response during stress echocardiography test. Out of 88 patients with MI 54 (61%) had anginal pain (patients with symptomatic MI), while 34 (39%) were free of symptoms (patients with silent MI). Level of exercise test, heart rate, time to the onset of ST segment depression, and the magnitude of ST segment depression were similar in both subgroups of the patients with MI. Duration of exercise test was longer in patients with silent MI (p < 0.05). Wall motion score index during stress echocardiography was higher in patients with symptomatic MI (p < 0.05). Coronary angiography findings were similar in patients with silent and those with symptomatic MI. During a five-yearsfollow-up period the occurrence of major cardic events (cardiac mortality and recurrent myocardial infarction) was similar in both subgroups of the patients with MI.

CONCLUSION

In more than one third of patients after myocardial infarction silent MI during stress echocardiography was detected. The patients with silent ischemia had longer duration of exercise test and smaller wall motion score index on stress echocardiography. There was no difference in coronary angiography finding between patients with silent and those with symptomatic MI. The incidence of major cardiac events during a five- years- follow-up was similar in the patients with silent and those with symptomatic MI.

The development of heart failure in patients with stable angina pectoris

BACKGROUND

To describe the clinical characteristics of patients with stable angina pectoris who develop heart failure and the events preceding its onset.

METHODS AND RESULTS

Of 7665 patients with stable angina in the ACTION trial, which compared long-acting nifedipine to placebo, 207 (2.7%) developed heart failure (HF) during a mean follow-up of 4.9 years. Those who developed HF were significantly (P<0.05) older, more often had diabetes, had a more extensive history of cardiovascular disease, lower ejection fractions, a higher serum creatinine and glucose, a lower haemoglobin, and were more often on blood pressure lowering drugs. A cardiac event or an intervention (n=155), a significant non-cardiac infection (n=19) or poor control of hypertension (n=12) preceded the development of HF in 186/207 cases (90%). There was no obvious precipitating factor in the remaining 21 patients (10%). Myocardial infarction increased the risk of the development of new HF within one week more than 100-fold. Nifedipine reduced the incidence of HF by 29% (P=0.015).

CONCLUSIONS

The development of heart failure is uncommon in patients with stable angina, and even less so in the absence of an obvious precipitating factor.

Treatment of stable angina

Severe atherosclerotic narrowing of one or more coronary arteries is responsible for myocardial ischemia and angina pectoris in most patients with stable angina pectoris. The coronary arteries of patients with stable angina also contain many nonobstructive plaques, which are prone to fissures or rupture resulting in presentation of acute coronary syndromes (unstable angina, myocardial infarction, sudden ischemic death). In addition to symptomatic relief of symptoms and an increase in angina-free walking time with antianginal drugs or revascularization procedures, the recent emphasis of treatment has been to reduce adverse clinical outcomes (coronary death and myocardial infarction). The role of smoking cessation, aspirin, treatment of elevated lipids, and treatment of high blood pressure in all patients and of beta-blockers and angiotensin-converting enzyme inhibitors in patients with diminished systolic left ventricular systolic function in reducing adverse outcomes has been well established. What is unknown, however, is whether any anti-anginal drugs (beta-blockers, long-acting nitrates, calcium channel blockers) effect adverse outcomes in patients with stable angina pectoris. Recent trials evaluated the usefulness of suppression of ambulatory ischemia in patients with stable angina pectoris, but it remains to be established whether suppression of ambulatory myocardial ischemia with antianginal agents or revascularization therapy is superior to pharmacologic therapy targeting symptom relief. Patients who have refractory angina despite optimal medical treatment and are not candidates for revascularization procedures may be candidates for newer techniques of transmyocardial revascularization, enhanced external counterpulsation, spinal cord stimulation, or sympathectomy. The usefulness of these techniques, however, needs to be confirmed in large randomized clinical trials.