742-6 Prognostic Significance of Change in Resting Left Ventricular Ejection Fraction Early After Successful Coronary Artery Bypass Surgery: A Long-term Follow-up Study

Although resting left ventricular ejection fraction (LVEF) is routinely determined as part of the preoperative evaluation of patients undergoing coronary artery bypass graft (CABG) surgery, the value of repeating the LVEF determination after the surgery has not been established. To investigate whether the change in LVEF between pre- and early post-CABG had long-term prognostic significance, records for all 303 patients who underwent successful CABG surgery (no peri- or 30 day post-operative mortality) between 1982–1984 at our institution (WR) and had both pre- and postoperative first-pass radionuclide ventriculography were reviewed. The survival status of 255 patients (254 male) was determined from responses to mailed questionnaires, telephone interviews, and reviews of medical records and computerized death registries. Pre-CABG (mean 8.8 days) and predischarge (mean 7.4 days postCABG) LVEFs were tabulated, with an absolute change of ≥5% (increased or decreased) considered significant. Long-term survival probability was examined using Kaplan-Meier curves for three patient groups based upon preCABG LVEF: Normal (Nil: ≥ 47% (long-established value with camera used); Moderately reduced (Mod): 35–46%; Severely reduced (Sev):  l35%. Results were as follows: Pre-CABG LVEF Number of Patients with Change in lVEF (Mean ± 1 std dev) Increased No Change Decreased Total Nl(52.8 ± 8.1%) 66 46 18 130(52%) Mod (40.9 ± 3.6%) 54 34 5 93(36%) Sev (30.0 ± 3.6%) 20 11 1 32(12%) Tolal 140(55%) 91(36%) 24(9%) 255 Patients ranged in age from 34–77 (mean 58), with no difference in mean age for the nine subgroups. Ten-year survival probabilities relative to preCABG LVEF were: Pre-CABG LVEF lVEF Increased LVEF No Change lVEF Decreased Nl 79.2% 77.3% 70.8% Mod 69.2% * 42.8% 40.0% Sev 47.6% 36.4% - * p l 0.05 versus ModlNo Change or Decreased Conclusion Among patients with Mod LVEF pre-CABG, early postoperative improvement was associated with a significant long-term survival advantage, a finding not seen among patients with NI and Sev pre-CABG LVEF. Early post-CABG LVEF determination appears of value in patients with Mod LVEF to identify the two prognostic groups as an aid for planning follow-up monitoring.