Follow-up
The New York Heart Association (NYHA) class, percentage of systolic
anterior motion (SAM), and LVOTO were significantly improved after the
surgery. There were no differences in the incidences of LVOTO and SAM
among the four groups. Detailed information is presented in Table 3. In
addition, coronary artery computed
tomography was performed in 49 patients 1 year after the surgery (15 in
the CABG with LIMA, 19 in the CABG with SVG group, and 15 in the
myocardial unroofing group). The graft remained patent in only 2
(13.3%) patients in the LIMA group and 16 (84.2%) patients in the SVG
group. However, no MB was detected in the myocardial unroofing group.
The mean follow-up period was 34.2±17.2 months. A total of 31 events
occurred: 24 patients died (20 patients without MB, 1 patient in the
CABG group, 1 patient in the unroofing group, and 2 patients in the
untreated group) and 7 patients (2 patients in the CABG group, 1 patient
in the unroofing group, and 4 patients in the untreated group) had a
non-fatal MI. Of the aforementioned deaths, 4 were due to cancer, 10 due
to sudden cardiac death, 8 due to heart failure, 1 due to MI, and 1 due
to infective endocarditis. The 3-year cumulative event-free survival of
all-cause death (p=0.89) and cardiovascular death (p=0.63) were similar
among the four groups (Figure 3 A and B). However, compared with the
other three groups, the 3-year cumulative event-free survival of
nonfatal MI (p<0.001) and combined endpoints of all 3 events
(including all-cause death, cardiovascular death, and nonfatal MI)
(p=0.02) were significantly lower in the no-treatment MB group (Figure 3
C and D).
Univariable and multivariable Cox regression analysis were performed to
investigate the predictors of combined endpoints in the follow-up period
(Table 4). Cox regression analysis indicated that non-treated MB was a
significant independent predictor of combined endpoints (HR: 4.06, 95%
CI: 1.60–10.32, p<0.001). In addition, the NYHA class III or
IV (HR: 4.72, 95% CI: 1.12–19.92, p=0.04) and postoperative hospital
stays (HR: 1.07, 95% CI: 1.03–1.11, p=0.001) were also independent
predictors of combined endpoints of all three events.