Relationship of left atrial expansion index to exercise tolerance, pretest probability of restenosis, and positive predictive value of treadmill test in coronary artery disease.

Background Whether left atrial (LA) expansion index is associated with coronary restenosis, and exercise capacity (EC) reduction in coronary artery disease has not been established. Methods This study analyzed 342 consecutive patients who had received a coronary stent implant. A treadmill exercise test (TET) was administered in all participants. The LA expansion indices were measured immediately before and after TET. Maximal EC measured on a breath-by-breath basis by a metabolic cart with gas analyzers and recorded as metabolic equivalent task. All patients with positive TET results received angiography, and those with restenosis received complete revascularization by either percutaneous coronary intervention (PCI) or bypass surgery. The LA expansion index and EC before and 1 month after PCI were then compared. Results Out of 342 patients, 74 had positive TET results, and 54 had restenosis in angiography. Low LA expansion index was associated with poor EC. In patients with LA expansion index > 200%, only 5% had restenosis with 38.5% positive predictive value (PPV) of TET. In patients with LA expansion index < 100%, however, 64.3% had restenosis with 94.7% PPV of TET. Restenosis induced low pre-TET LA expansion index and further decline during TET. The LA expansion index significantly (P .001) improved from 133 +/- 64% before PCI to184 +/- 86% after PCI, and the improvement corresponded with EC recovery. A 10% reduction in LA expansion index was associated with a 15% increase in pretest probability of restenosis. Conclusion The LA expansion index is associated with EC, pretest probability of restenosis, and PPV of TET. Revascularization improves both EC and LA expansion index.