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Improvement of myocardial perfusion and left ventricular function after coronary artery bypass grafting in patients
Insights
Coronary artery bypass surgery improved myocardial perfusion and left ventricular function in unstable angina patients. Improved perfusion correlated with better exercise tolerance, indicating surgery
Area of Science:
- Cardiology
- Cardiac Surgery
- Nuclear Cardiology
Background:
- Unstable angina presents with myocardial perfusion defects and impaired left ventricular function.
- Coronary artery bypass graft (CABG) surgery is a common treatment for severe coronary artery disease.
Purpose of the Study:
- To evaluate changes in myocardial perfusion and left ventricular (LV) function after CABG surgery in patients with unstable angina.
- To assess the relationship between improved perfusion, LV function, angina symptoms, and exercise tolerance post-surgery.
Main Methods:
- Intracoronary and intragraft injections of radiolabeled macroaggregated albumin particles were used to assess myocardial perfusion.
- Left ventriculography was performed to evaluate segmental wall motion.
- Patients were assessed pre- and post-operatively (3-6 months).
Main Results:
- Of 20 preoperative perfusion defects, 13 improved post-CABG.
- 29 of 29 abnormally contracting LV segments showed improved wall motion, with 18 normalizing.
- Improved perfusion correlated with improved LV wall motion and significantly better treadmill exercise tolerance.
- 13 of 14 patients reported reduced angina, but only those with improved perfusion showed enhanced exercise capacity.
Conclusions:
- Coronary artery bypass graft surgery can reverse perfusion defects in patients with unstable angina.
- Reversal of perfusion abnormalities leads to improved left ventricular performance and exercise tolerance.
- Improved myocardial perfusion is a key factor for enhanced functional recovery and exercise capacity post-CABG.
Abstract:
Changes in myocardial perfusion and left ventricular function were evaluated pre- and post-operatively (3--6 months) in 14 patients with unstable angina who underwent coronary artery bypass surgery. Perfusion was studied with intracoronary and intragraft injections of radiolabeled macroaggregated albumin particles. Of 20 abnormal perfusion areas identified preoperatively, 13 demonstrated improved perfusion post-operatively. Segmental analysis of the left ventriculogram demonstrated improved wall motion in 29 abnormally contracting segments; 18 normalized. Areas which showed improvement of left ventricular perfusion were invariably associated with improvement of left ventricular wall motion. Five patients showed improvement in perfusion and contraction in areas of apparent old myocardial infarction. Thirteen of the 14 patients had significantly less angina whether or not there was evidence of improved perfusion. However, only those patients who demonstrated improved perfusion had a significant improvement in their treadmill exercise tolerance postoperatively. Thus, patients with unstable angina have perfusion defects which may be reversed as a result of saphenous vein graft surgery. Reversal of these perfusion abnormalities results in improved left ventricular performance and better exercise tolerance postoperatively.