Hibernation and congestive heart failure

The Impact of Complete Revascularization in Symptomatic Severe Left Ventricular Dysfunction between Coronary Artery Bypass Graft and Percutaneous Coronary Intervention

Objective

The study aimed to compare the clinical outcomes between the patients receiving coronary artery bypass surgery (CABG) or percutaneous coronary intervention (PCI) for the patients with symptomatic severe left ventricular (LV) dysfunction and coronary artery disease (CAD).

Methods

Between February 2007 and February 2020, a total of 745 patients who received coronary artery angiography for reduced LV ejection fraction (LVEF) < 40% and symptomatic New York Heart Association (NYHA) functional class ≥ 3 were recruited. The patients (N = 236) who were diagnosed with dilated cardiomyopathy or valvular heart disease without coronary artery stenosis, those with prior history of CABG or valvular surgery (N = 59), those who presented ST-segment elevated myocardial infarction (STEMI), those with a CAD and SYNTAX score of  ≦ 22 (N = 175), those who received emergent CABG for coronary perforation (N = 3), and those who had NYHA class ≦ 2 (N = 65) were excluded. Finally, 116 patients with reduced LVEF and those who had a SYNTAX score >22, who received CABG (N = 47) and PCI (N = 69), were recruited for this study.

Results

There was no significant difference in the incidence values of in-hospital course and those of in-hospital mortality, acute kidney injury, and postprocedural hemodialysis. There was no significant difference in the 1-yearfollow-up of recurrent MI, revascularization, or stroke between the groups. The 1-year heart failure (HF) hospitalization rate was significantly lower in the CABG group than in all patients of the PCI group (13.2% vs. 33.3%; p = 0.035); however, there was no significant difference in the same variable between the CABG group and the complete revascularization subgroup (13.2% vs. 28.2%; p = 0.160). The revascularization index (RI) was significantly higher in the CABG group than in all patients of the PCI group or complete revascularization subgroup (0.93 ± 0.12 vs. 0.71 ± 0.25; p < 0.001) and (0.93 ± 0.12 vs. 0.86 ± 0.13; p = 0.019). The 3-year HF hospitalization rate was significantly lower in the CABG group than in all patients of the PCI group (16.2% vs. 42.2%; p = 0.008); however, there was no difference in the same variable between the CABG group and the complete revascularization subgroup (16.2% vs. 35.1%; p = 0.109).

Conclusions

In patients with symptomatic (NYHA class ≥ 3) severe LV dysfunction and CAD, CABG brought less HF admission when compared to patients in the PCI group, but this did not differ when compared to the complete revascularization subgroup. Therefore, an extensive revascularization, achieved by CABG or PCI, is associated with a lower HF hospitalization rate during the 3-yearfollow-up period in such populations.

Distribution of Intraportally Implanted Microspheres and Fluorescent Islets in Mice

The aim of the study was to evaluate the distribution of intraportally transplanted islets in mice. We initially administered 2000 polystyrene microspheres with a diameter of 50 μm intraportally into normoglycemic C57BL/6 mice. In separate experiments other mice were injected similarly with 300 microspheres each with a diameter of 100 or 200 μm. One week later the animals were killed, and the lungs and livers were removed and divided into lobes. The number of microspheres in each individual liver lobe and in the lungs was counted using a stereomicroscope. In other experiments, athymic C57BL/6 mice were similarly implanted with 250 islets isolated from transgenic mice expressing the enhanced yellow fluorescent protein in the islet cells. The distribution of microspheres and islets was independent of size, and fairly homogenous within the liver, with the exception of the caudate lobe, which contained fewer microspheres and islets, respectively. Approximately one third of all microspheres and islets were present as aggregates. Eighty-five to 90% of the implanted microspheres were identified in the liver sections, whereas 60–65% of the implanted islets were recovered. Aggregates or single fluorescent cells were observed in the liver of islet-implanted mice. We conclude that islets and microspheres implanted into the liver distribute fairly homogenously and quite a few of them exist as aggregates or, with respect to islets, as fragments.

Phase analysis of gated myocardial perfusion single-photon emission computed tomography after coronary artery bypass graft surgery: reflection of late reverse remodeling in patients with patent grafts after coronary artery bypass graft surgery

OBJECTIVE

Phase analysis using gated myocardial perfusion single-photon emission computed tomography (GMPS) is a tool used to assess left ventricular (LV) dyssynchrony. We attempted to investigate the role of LV dyssynchrony assessed by GMPS using phase analysis for the late LV function after coronary artery bypass graft surgery (CABG) in patients with patent grafts.

METHODS

A total of 45 patients who received off-pump CABG with patent graft 1 year after CABG and preserved perfusion reserve were enrolled retrospectively. All patients underwent GMPS before and 3 months and 1 year after CABG. Using the Emory Cardiac Toolbox, both phase histogram bandwidth (PBW) and phase SD derived by phase analysis were used for the analysis, in addition to the conventional perfusion parameters. For the evaluation of LV function, transthoracic echocardiography was also performed.

RESULTS

All of the patients showed perfusion improvement (paired t-test, P<0.05) after CABG. Nonetheless, 30 of 45 patients showed LV dyssynchrony 3 months after CABG. One year after CABG, however, 25 out of 45 patients showed reverse remodeling. Among those patients with reverse remodeling, 19 patients had shown LV 3 months after CABG. Using stepwise logistic regression with forward selection, PBW 3 months after CABG could predict reverse remodeling 1 year after CABG (odds ratio 1.03, P<0.05). Using receiver operating characteristic analysis, PBW 3 months after CABG had the largest area under the curve to detect reverse remodeling 1 year after CABG with a cut-off value of 82 (sensitivity 0.95, specificity 0.56, P<0.001).

CONCLUSION

Postoperative LV dyssynchrony assessed by GMPS using phase analysis may reflect late reverse remodeling and potential of further functional improvement in patients with patent grafts and preserved perfusion reserve after CABG.

The presence of electromechanical mismatch in nonischemic dilated cardiomyopathy is associated with ventricular repolarization instability

BACKGROUND

We analyzed electromechanical mismatch (EMM) and its relationship to ventricular repolarization in patients with nonischemic dilated cardiomyopathy (DCM).

METHODS AND RESULTS

In 39 DCM patients with left ventricular ejection fraction (LVEF) <40% and New York Heart Association functional class ≥III, electroanatomic mapping was used to quantify areas of EMM. High-resolution electrocardiograph was used to measure heart rate variability (HRV) and QT variability index (QTVI). EMM was present in 22 patients (56%, group 1), whereas 17 patients presented no mismatched segments (44%, group 2). The groups did not differ in age (56 ± 10 years in group 1 vs 57 ± 7 years in group 2; P = .82), sex (male: 82% vs 94%; P = .40), LVEF (27 ± 8% vs 25 ± 6%; P = .18), or N-terminal pro-B-type natriuretic peptide (2,350 pg/mL vs 2,831 pg/mL; P = .32). Although heart rate and HRV were similar in both groups (rate: 80 ± 20 beats/min in group 1 vs 74 ± 19 beats/min in group 2 [P = .47]; standard deviation of normal-to normal RR intervals: 106 ± 79 vs 88 ± 115 [P = .61]), we found significantly higher QTVI values in patients from group 1 (-1.15 ± 0.46 vs -1.62 ± 0.51 in group 2; P = .005). In patients with implantable cardioverter-defibrillators, ventricular arrhythmias recorded ≤1 year before enrollment were more frequent in group 1 than in group 2 (58% vs 13%; P = .02).

CONCLUSIONS

EMM is present in a majority of patients with DCM and is associated with ventricular repolarization instability.

Impaired myocardial oxidative metabolism in the remote normal region in patients in the chronic phase of myocardial infarction and left ventricular remodeling

BACKGROUND

Left ventricular (LV) remodeling occurs in the remote normal region in the LVs after myocardial infarction (MI) and is closely involved in heart failure.

METHODS

We assessed myocardial oxygen consumption using a clearance rate constant K (mono) for the time activity curves of (11)C-acetate in 15 patients with a prior anterior wall MI, 8 with a prior inferior wall MI, and 10 age-matched normal control subjects. LV end-systolic volume index (ESVI) was determined by echocardiography.

RESULTS

The LVESVI was significantly greater in patients with an anterior and inferior MI than in control subjects. The heart rate systolic pressure product did not differ among the groups. K (mono) in the remote normal region in patients with an anterior MI was significantly less than that in the corresponding area in control subjects (0.055 +/- 0.005 vs 0.065 +/- 0.008 min(-1), P < .001). K (mono) in the remote normal region in those with an inferior MI was also significantly less compared with controls (0.054 +/- 0.007 vs 0.069 +/- 0.010 min(-1), P < .01).

CONCLUSION

In patients with a prior MI and LV remodeling, myocardial oxidative metabolism is apparently impaired in the remote normal region where augmented myocardial energy production is needed against the increased end-systolic wall stress caused by LV dilatation.