The Recovery of Left Ventricular Function after Coronary Artery Bypass Grafting in Patients with Severe Ischemic Left Ventricular Dysfunction: Off-pump Versus On-pump / 대한흉부외과학회지

BACKGROUND: Adverse effects of cardiopulmonary bypass can be avoided by "Off-pump" coronary artery bypass (OPCAB) surgery. Recent studies have reported that OPCAB had the most beneficial impact on patients at highest risk by reducing bypass-related complications. The purpose of this study is to compare the outcome of OPCAB and conventional coronary artery bypass grafting (CCAB) in patients with poor left ventricular (LV) function. MATERIAL AND METHOD: From March 1997 to February 2004, seventy five patients with left ventricular ejection fraction (LVEF) of 35% or less underwent isolated coronary artery bypass grafting at our institute. Of these patients, 33 patients underwent OPCAB and 42 underwent CCAB. Preoperative risk factors, operative and postoperative outcomes, including LV functional change, were compared and analysed. RESULT: Patients undergoing CCAB were more likely to have unstable angina, three vessel disease and acute myocardial infarction among the preoperative factors. OPCAB group had significantly lower mean operation time, less numbers of total distal anastomoses per patient and less numbers of distal anastomoses per patient in the circumflex territory than the CCAB group. There was no difference between the groups in regard to in-hospital mortality (OPCAB 9.1% (n=3) Vs. CCAB 9.5% (n=4)), intubation time, the length of stay in intensive care unit and in hospital postoperatively. Postoperative complication occurred more in CCAB group but did not show statistical difference. On follow-up echocardiography, OPCAB group showed 9.1% improvement in mean LVEF, 4.3 mm decrease in mean left ventricular end-diastolic dimension (LVEDD) and 4.2 mm decrease in mean left ventricular end-systolic dimension (LVESD). CCAB group showed 11.0% improvement in mean LVEF, 5.1 mm decrease in mean LVEDD and 5.5 mm decrease in mean LVESD. But there was no statistically significant difference between the two groups. CONCLUSION: This study showed that LV function improves postoperatively in patients with severe ischemic LV dysfunction, but failed to show any difference in the degree of improvement between OPCAB and CCAB. In terms of operative mortality rate and LV functional recovery, the results of OPCAB were as good as those of CCAB in patients with poor LV function. But, OPCAB procedure was advantageous in shortening of operative time and in decrease of complications. We recommend OPCAB as the first surgical option for patients with severe LV dysfunction.

Changes of Pulmonary Artery Pressure during Liver Transplantation / 대한마취과학회지

BACKGROUND: Pulmonary hypertension (PH) associated with end stage liver disease is rare but the risk of hemodynamic deterioration during liver transplantation may be high. This study was done to characterize the pulmonary hemodynamics during liver transplantation and to seek the relationship between pulmonary artery pressure (PAP) and other hemodynamic variables. METHODS: One hundred patients undergoing liver transplantation were chosen and we divided patients into normal and PH groups (mean pulmonary artery pressure [MPAP] > 25 mmHg). Hemodynamic data was collected throughout the surgery. Studied variables between groups were analyzed with an unpaired t-test. The relationship between MPAP and other hemodynamic variables was analyzed with a linear regression test. Survival analysis was performed by cumulative survival analysis (Logrank test). RESULTS: Incidence of PH during liver transplantation was 34%, and true PH (pulmonary vascular resistance index [PVRI] > 150 dyne.sec/cm5/m2, MPAP > 25 mmHg) was 7%. MPAP, systemic vascular resistance index, cardiac index, right ventricular ejection fraction, maximum elastance, central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), and right ventricular end-diastolic volume index were significantly higher in the PH group. In the PH group, right ventricular function curve was abnormal. MPAP correlated significantly with PAOP, and CVP (P < 0.01). One year survival rate showed no significant difference between groups (Logrank test P = 0.49). CONCLUSIONS: Episodes of increased pulmonary artery pressure during liver transplantation was not infrequent. PAP was more dependent on preloads. In patients with high PAP, RV diastolic dysfunction was usually observed. Early mortality rate after liver transplantation was not associated with PH.

Rapid Left ventricular Training after Arterial Switch Operation in Transposition of Great Arteries with Left Ventricular Outflow Tract Obstruction and ventricular Septal Defect: 1 case report / 대한흉부외과학회지

There have been few reports documenting the outcome of arterial swich operations(ASO) in selected patients with transposition of great arteries(TGA) and with left ventricular outflow tract obstruction(LVOTO). In the case of TGA with LVOTO, if the atrial septal defect(ASD) is large and the ventricular septal defect(VSD) is restricive, this deprives the left ventricle(LV) of approporiate preload and could lead to underdevelopment of the ventircular mass and lead poor LV performance after the arterial switch operation, dspite a high pressure in the LV preoperatively. Because an increase in the systolic ventricular pressure is not necessarily paralleled by an increase in ventricular mass, which is also essential for optimal ventricular performance after the operation. We report here a case of rapid LV training after ASO in TGA with unprepared LV (because of large ASD and restrictive VSD) despite a high pressure in the LV(due to LVOTO) preoperatively.

Assessment of Right Ventricular Function During Orthotopic Liver Transplantation / 대한마취과학회지

BACKGROUND: Patients undergoing orthotopic liver transplantation(OLT) may develop significant hemodynamic instability. This study was performed to assess the role of right ventricular function in the hemodynamic alteration during 23 cases of OLT. METHODS: A thermodilution ejection fraction catheter was used to measure ejection fraction(EFrv), allowing for calculation of right ventricular(RV) end-diastolic volume index(EDVIrv), end-systolic volume index(ESVIrv), stroke volume index(SVIrv). RV stroke work index(SWIrv), maximum elastance (Emaxrv) and performance index(PIrv) as the functions of contractility were also calculated. Those RV hemodynamic measures were taken during preanhepatic phase(stage I), anhepatic phase (stage II), after reperfusion of the grafted liver and postanhepatic phase (stage III). All of measures in each surgical stage were statistically analyzed for their differences by repeated measured ANOVA. And correlation between changes from baseline of RV hemodynamic variables was determined by polynomial regression analysis. RESULTS: EFrv, SVIrv, SWIrv appeared to be well preserved throughout the prdegrees Cedure during stage I, II, III and much higher 5 min after reperfusion. No correlation was observed between right atrial pressure(Pra) and EDVIrv. There were significant correlation between EDVIrv and SVIrv, SWIrv and EFrv, Emaxrv and EFrv. CONCLUSION: RV function was well preserved during uncomplicated OLT using venovenous bypass. EDVIrv were more reliable determinants of RV preload than Pra for assessing RV contractility under conditions of this operation.

Analysis of the Right Ventricular Pressure/Volume Relationship and Contractility During Liver Transplantation / 대한마취과학회지

BACKGROUND: Hemodynamic instability is one of the main concerns for anesthesiologists during orthotopic liver transplantation (OLTX). The most troublesome event would be an increase of central venous pressure associated with sudden right ventricular (RV) filling without any change in heart contractility. An acute increase in RV outflow pressure depresses RV contractility and eventually causes overt RV failure. To avoid such disaster, it would be wise to evaluate right heart pressure/volume relationship and assess contractility when anticipating acute increase of pressure in right heart chamber. METHODS: RV function was assessed in 15 patients undergoing OLTX. RV function was monitored using an ejection fraction catheter and a monitor. Complete hemodynamic profile was obtained on regular intervals. Statistical analysis was performed using ANOVA for repeated measures. Correlation between variables were determined by simple regression analysis and ANCOVA. RESULTS: RV end-diastolic volume was in the range of supranormal values. No correlation was observed between right atrial pressure and RV end-diastolic volume index (RVEDVI). There was a significant correlation between stroke index and RVEDVI. RV ejection fraction and E-single were relatively constant throughout the procedure. There was weak negative correlation between E-signle and RVEDVI. CONCLUSION: RV function appeared to be well preserved during OLTX. However, RV contractility tends to decrease in response to RVEDV increase because RVEDV of endstage liver disease might increase to their maximal value. Right heart filling pressure was less reliable clinical indicator of RV preload.