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Silent ischemia during coronary occlusion produced by balloon inflation: relation to regional myocardial dysfunction
Insights
Silent myocardial ischemia is common during coronary angioplasty. The absence of chest pain does not indicate less heart muscle damage, highlighting the importance of objective monitoring during the procedure.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiovascular Physiology
Background:
- Stable exertional angina is a common condition often treated with percutaneous transluminal coronary angioplasty (PTCA).
- The relationship between anginal symptoms during PTCA and the extent of myocardial ischemia is not fully understood.
Purpose of the Study:
- To investigate the correlation between angina induced by balloon inflation and the severity of myocardial ischemia during PTCA.
- To compare electrocardiographic (ECG) and echocardiographic assessments of ischemia in patients experiencing symptomatic versus asymptomatic balloon inflations.
Main Methods:
- Prospective evaluation of 30 patients with stable exertional angina undergoing PTCA of the proximal left anterior descending artery.
- Continuous 2D echocardiography and 12-lead ECG monitoring during the first two balloon inflation sequences.
- Categorization into symptomatic, asymptomatic, and mixed response groups based on anginal pain reports.
Main Results:
- Seventeen patients were symptomatic, seven asymptomatic, and six had mixed responses to balloon inflations.
- No significant differences in left ventricular dysfunction (echocardiography) or ST-segment changes (ECG) between symptomatic and asymptomatic groups.
- Mixed response group showed comparable ischemia during painful and painless inflations, mirroring findings in the other groups.
Conclusions:
- Silent myocardial ischemia is prevalent during coronary angioplasty.
- Absence of angina during balloon inflation does not preclude significant myocardial ischemia.
- Objective assessments like ECG and echocardiography are crucial for evaluating ischemia, irrespective of patient-reported symptoms.
Abstract:
Thirty patients with stable exertional angina undergoing percutaneous transluminal coronary angioplasty of an isolated obstructive lesion of the proximal left anterior descending artery were prospectively evaluated to investigate the relation between angina induced by balloon inflation and the quantity and severity of myocardial ischemia as determined by electrocardiographic (ECG) monitoring and by echocardiographic assessment of regional and global left ventricular wall motion. Anginal pain interviews, continuous two-dimensional echocardiographic recordings and 12 lead ECG recordings at 10 second intervals were obtained for the first two inflation sequences. Seventeen patients had angina with both inflations (symptomatic group), seven patients had no angina or related symptoms during either inflation (asymptomatic group) and six patients had both painful and painless inflations (mixed response group). Comparison of the three groups revealed that they did not differ in mean age, sex distribution, prior history of angina or the incidence of comorbid conditions. Echocardiographic measurements of global and regional left ventricular dysfunction during balloon inflation were comparable in the symptomatic and asymptomatic groups. Similarly, there were no significant differences in the time to onset or magnitude of ST segment changes. The results of the wall motion and ECG studies in the mixed response group paralleled the results in the symptomatic and asymptomatic groups, with no significant differences in any of the variables measured between the painful and painless inflations. These data demonstrate that silent myocardial ischemia occurs in an appreciable proportion of patients during coronary angioplasty and the absence of angina does not imply that a lesser amount of myocardium is jeopardized than with painful inflations.