• Journal of Chest Surgery
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• v.25 no.3
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• pp.307-314
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• 1992

The internal mammary artery has been advocated for use in bypass grafting owing to its superior long-term patency when compared to saphenous vein grafts. Concern exists that the flow through internal mammary artery may be inadequate during periods of peak myocardial demand when the internal mammary artery graft was used for proximal left anterior descending artery stenosis. This flow adequacy was investigated in 13 consecutive patients with a mean proximal left anterior descending artery stenosis of 84.2% who were selected for coronary bypass using internal mammary artery. We checked flow and diameter of left internal mammary artery without intraluminal dilatation just before anastomosis to left anterior descending artery during cardiopulmonary bypass. Clinical results were evaluated postoperatively with clinical symptoms, echocardiographies, stress tests, and coronary angiographies. The mean internal mammary artery flow measured just before anastomosis was 38ml/ min[range of 20 to 80ml /min] and its mean internal diameter 1.4mm. Maximal workload was improved from preoperative value of 6.3$\pm$2.5METS to postoperative value of 9.1$\pm$1.4 METS in 9 patients who Paired-test can be used. Cardiac symptoms recurred in two patients after bypass surgery, but they were not related to left internal mammary artery grafts. All patients were discharged in postoperatively 9.3 days[range of 7 to 20 days] after operation without mortality. Thus, on the basis of these findings, the internal mammary artery is a reasonable graft that we can routinely use for proximal left descending artery stenosis if internal diameter of the internal mammary artery is more than 1.0mm and its flow is more than 20ml /min at mean arterial pressure of 50 to 60mmHg during cardiopulmonary bypass.

• Journal of Chest Surgery
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• v.52 no.3
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• pp.155-161
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• 2019

Background: Coronary artery bypass grafting (CABG) is being offered increasingly frequently to octogenarians. However, old age is known to be an independent risk factor in CABG. The aim of this study was to compare the outcomes of off-pump coronary artery bypass (OPCAB) between octogenarians and septuagenarians. Methods: We retrospectively reviewed the data of 1,289 consecutive patients aged ${\geq}70years$ who underwent OPCAB at a single institution between 2001 and 2016. We compared the outcomes of 115 octogenarians and 1,174 septuagenarians. Using propensity score matching, based on preoperative clinical characteristics, 114 octogenarians were matched with 338 septuagenarians. Results: Propensity score analysis revealed that the incidence of acute kidney injury (14.9% vs. 7.9%, p=0.028) and respiratory complications (8.8% vs. 4.2%, p=0.040) was significantly higher in octogenarians. The early mortality rate (2.6% vs. 1.0%, p=0.240) and 1-year survival rate (89.5% vs. 94.4%, p=0.097) were not statistically significant between the groups. However, the 5-year survival rate (67.3% vs. 79.9%, p<0.001) was significantly lower in octogenarians. Previous myocardial infarction and a left ventricular ejection fraction ${\leq}35%$ were associated with a poor 1-year survival rate. Conclusion: Early and 1-year outcomes of OPCAB in octogenarians were tolerable when compared with those in septuagenarians. OPCAB could be a suitable option for octogenarians.

• Biomedical Science Letters
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• v.17 no.4
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• pp.329-336
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• 2011

The female has previously been shown to be an independent risk factor for mortality and morbidity after coronary artery bypass grafting surgery (CABG). The aim of this retrospective study is to evaluate gender differences of the perioperative outcomes in elderly patients underwent CABG. Data for seventy elderly patients (>70 years) that underwent CABG (between January 2005 and July 2011) were divided into two groups: male patients (n=33, male group) and female patients group (n=37, female group). Heights, body weights, body surface area and coronary artery obstruction rate (right coronary artery territory) in the female group were lower than those of the male group ($P$ <0.05). History of hypertension, hyperlipidemia, congestive heart failure and percutaneous coronary artery intervention in the female group was higher than that of the male group ($P$ <0.05). Total cholesterol and brain natriuretic peptide levels in the female group were higher than those of the male group ($P$ <0.05). Platelet count in the female group was higher than the male group at preoperative (Pre-OP) period ($P$ <0.05). Erythrocyte count, hematocrit and hemoglobin levels in the female group were lower than those of the male group at Pre-OP period ($P$ <0.05). But, erythrocyte count, hematocrit and hemoglobin levels in the female group were higher than those of the Male group at postoperative (Post-OP) period ($P$ <0.05). Left ventricular ejection fraction in the female group was higher than the male group at Post-OP period ($P$ <0.05). Hospital stay length in the female group was higher than the male group ($P$ <0.05). Post-OP bleeding volume and incidence of ventricular premature contraction in the female group were lower than those of the male group ($P$ <0.05). These results suggest that despite female gender have a greater risk factors and require a longer hospitalization than male, there was no significant difference incidence of mortality and complication.

• Biomedical Science Letters
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• v.17 no.4
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• pp.337-345
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• 2011

It is well recognized that conventional coronary artery bypass grafting (ONCAB) often leads to major organ dysfunction including renal injury. Diabetes mellitus is a major cause of nephropathy and poor clinical outcomes. The aim of this retrospective study was to evaluate the occurrence of adverse outcomes including renal impairment between diabetic (n=75, DM group) and non-diabetic patients (n=72, Non-DM group) underwent off-pump coronary artery bypass grafting surgery (OPCAB). Fasting glucose, hemoglobin A1c, fructosamine, fibrinogen and serum osmolality levels in the DM group were higher than those of the Non-DM group at pre-operative (Pre-OP) period ($P$ <0.05). History of hypertension and renal impairment in the DM group was higher than that of the Non-DM group ($P$ <0.05). Potassium ($K^+$), blood urea nitrogen and creatinine levels were higher, whereas sodium ($Na^+$) and glomerular filtration rate (GFR) levels were lower in the DM group than the Non-DM group at peri-operative period ($P$ <0.05). Fasting glucose levels at Pre-OP period had positive correlations with blood urea nitrogen and creatinine levels at peri-operative period, but negative correlations with GFR levels at peri-operative period in the DM group ($P$ <0.05). Incidences of renal impairment, diuretic therapy or continuous renal replacement therapy and fever in the DM group were higher than those of the Non-DM group at post-operative period ($P$ <0.05). These results suggest that blood glucose level should be tightly controlled at peri-operative period to avoid renal dysfunction in diabetic patients.

• Journal of Chest Surgery
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• v.51 no.1
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• pp.8-14
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• 2018

Background: Minimally invasive direct coronary artery bypass grafting (MIDCAB) has the advantage of allowing arterial grafting on the left anterior descending artery without a sternotomy incision. We present our single-center clinical experience of 66 consecutive patients. Methods: All patients underwent MIDCAB through a left anterior small thoracotomy between August 2007 and July 2015. Preoperative, intraoperative, postoperative and follow-up data - including major adverse cardiovascular and cerebrovascular events (MACCE), graft patency, and the need for re-intervention - were collected. Results: The mean age of the patients was $69.4{\pm}11.1years$ and 73% were male. There was no conversion to an on-pump procedure or a sternotomy incision. The 30-day mortality rate was 1.5%. There were no cases of stroke, although 2 patients had to be re-explored for bleeding, and 81.8% were extubated in the operating room or on the day of surgery. The median stay in the intensive care u nit and in the hospital were 1.5 and 9.6 days, respectively. The median follow-up period was 11 months, with a 5-year overall survival rate of $85.3%{\pm}0.09%$ and a 5-year MACCE-free survival rate of $72.8%{\pm}0.1%$. Of the 66 patients, 32 patients with 36 grafts underwent a postoperative graft patency study with computed tomography angiography or coronary angiography, and 88.9% of the grafts were patent at $9.7{\pm}10.8months$ postoperatively. Conclusion: MIDCAB is a safe procedure with low postoperative morbidity and mortality and favorable mid-term MACCE-free survival.

• Biomedical Science Letters
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• v.15 no.3
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• pp.207-215
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• 2009

We carried out this study to investigate differences of physiological variables between patients with (DM group) and without type II diabetes mellitus (Non-DM group) undergoing off-pump coronary artery bypass grafting (OPCABG). Postoperative $Mg^{++}$ and $Ca^{++}$ levels were lower, whereas $Na^+$ level was higher in DM group than those in Non-DM group. ICU (intensive care unit) stay time in DM group was longer than that of Non-DM group. Postoperative platelet counts tended to decrease, whereas C-reactive protein (CRP) and cardiac troponin-I (cTNI) levels tended to increase in DM group compared with Non-DM group. Postoperative albumin level was lower, while blood urea nitrogen (BUN) and creatinine levels were greater in DM group than those in Non-DM group. DM group had higher incidence of post-operative arrhythmias than Non-DM group. These results reveal that type II DM patients undergoing OPCAB may have higher incidences of postoperative hypomagnesemia, hypocalcemia and arrhythmias, and increases of CRP, cTNI, BUN, and creatinine levels than in Non-DM patients undergoing OPCAB. The perioperative check and control (supplement) of $Mg^{++}$ levels should be considered in cardiovascular surgery combined with DM.

• Journal of Chest Surgery
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• v.52 no.1
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• pp.16-24
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• 2019

Background: Optimal graft selection for coronary artery bypass grafting (CABG) in patients with severe left ventricular (LV) dysfunction remains debatable. We report an analysis of our experiences of isolated CABG in patients with severe LV dysfunction and the impact of graft strategy on long-term outcomes. Methods: We analyzed 209 patients with severe LV dysfunction (ejection fraction [EF] <30%) who underwent primary isolated CABG. Of these, 169 were revascularized with a bilateral internal thoracic arterial (ITA) graft (BITA group) and 40 were revascularized with a single ITA graft (SITA group). The mean follow-up duration was $22{\pm}32$ months. Results: There were 18 early deaths (8.6%). Overall survival at 5 years was 66.7%. The rate of freedom from cardiac-related death at 5 years was 74.1%, and was significantly higher in patients who underwent off-pump CABG (p=0.005) and in the BITA group (p=0.023). Multivariate analysis demonstrated that old age (hazard ratio [HR], 2.548; 95% confidence interval [CI], 1.134-5.762; p=0.024), off-pump CABG (HR, 0.245; 95% CI, 0.090-0.661; p=0.006), and BITA grafts (HR, 0.333; 95% CI, 0.146-0.757; p=0.009) were correlated with cardiac mortality. Conclusion: CABG in patients with severe LV dysfunction (EF <30%) showed reasonable long-term outcomes. The rate of freedom from cardiac-related death was significantly higher in patients who underwent off-pump CABG and in the BITA group. Off-pump BITA grafting strategies can be accepted as a viable primary option in patients with severe LV dysfunction if performed by an experienced surgeon.

• Journal of Chest Surgery
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• v.54 no.2
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• pp.117-126
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• 2021

Background: Several factors, such as the degree of target vessel stenosis, are known to be associated with radial artery (RA) graft patency in coronary artery bypass grafting (CABG). There is a lack of data regarding the effect of the RA proximal configuration (aortic anastomosis versus T-anastomosis). This study evaluated the effects of the RA proximal configuration on the patency rate and clinical outcomes after CABG. Methods: We conducted a retrospective study, analyzing 328 patients who had undergone CABG with an RA graft. We divided the patients into 2 groups. The primary endpoint was RA patency and the secondary endpoints were overall mortality and major adverse cardiac and cerebrovascular events (MACCE). We performed a propensity score-matched comparison. Results: Aorta-RA anastomosis was performed in 275 patients, whereas the rest of the 53 patients received T-RA anastomosis. The mean age was 67.3±8.7 years in the T-RA anastomosis group and 63.8±9.5 years in the aorta-RA anastomosis group (p=0.02). The mean follow-up duration was 5.13±3.07 years. Target vessel stenosis ≥70% (hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.20-0.91; p=0.03) and T-RA anastomosis configuration (HR, 2.34; 95% CI, 1.01-5.19; p=0.04) were significantly associated with RA occlusion in the multivariable analysis. However, T-RA anastomosis was not associated with higher risks of overall mortality and MACCE following CABG (p=0.30 and p=0.07 in the matched group, respectively). Conclusion: Aorta-RA anastomosis showed a superior patency rate compared to T-RA anastomosis. However, the RA proximal anastomosis configuration was not associated with mortality or MACCE.

• Journal of Chest Surgery
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• v.55 no.6
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• pp.442-451
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• 2022

Background: This meta-analysis was conducted to evaluate the effect of fractional flow reserve (FFR) on clinical outcomes after coronary artery bypass grafting (CABG). Methods: Five online databases were searched for studies that (1) enrolled patients who underwent isolated CABG or CABG with aortic valve replacement and (2) demonstrated the effect of an FFR-guided strategy on major adverse cardiac events (MACE) after surgery based on a randomized controlled trial or adjusted analysis. MACE included cardiac death, acute myocardial infarction (MI), and repeated revascularization. The primary outcomes were all MACE outcomes and a composite of all-cause death and MI, and the secondary outcomes were the individual MACE outcomes. Publication bias was assessed using a funnel plot and the Egger test. Results: Six articles (3 randomized and 3 non-randomized studies: n=1,027) were selected. MACE data were extracted from 4 studies. The pooled analyses showed that the risk of MACE was not significantly different between patients who underwent FFR-guided CABG and those who underwent angiography-guided CABG (hazard ratio [HR], 0.80; 95% CI, 0.57-1.12). However, the risk of the composite of death or MI was significantly lower in patients undergoing FFR-guided CABG (HR, 0.62; 95% CI, 0.41-0.94). The individual MACE outcomes were not significantly different between FFR-guided and angiography-guided CABG. Conclusion: FFR-guided CABG might be beneficial in terms of the composite outcome of death or MI compared with angiography-guided CABG although data are limited.

• Journal of Chest Surgery
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• v.56 no.5
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• pp.313-321
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• 2023

Background: This study evaluated the early, 1-year, and 3-year graft patency rates and mid-term clinical outcomes after no-touch saphenous veins (NT-SVs) were used as aortocoronary grafts in coronary artery bypass grafting (CABG). Methods: In total, 101 patients who underwent CABG using NT-SVs as aortocoronary grafts were included. The 2 most common indications for performing aortocoronary grafting with NT-SVs were unavailability of the left internal thoracic artery (n=36) and moderate lesions where flow competition was expected (n=27). Early (median, 1 day; interquartile range [IQR], 1-2 days), 1-year (median, 13 months; IQR, 11-16 months), and 3-year (median, 34 months; IQR, 27-41 months) graft angiography was performed in 98 (97.0%), 84 (83.2%), and 40 patients (39.6%), respectively. The median follow-up duration was 43 months (IQR, 13-76 months). Overall survival rates and the cumulative incidence of major adverse cardiac events were evaluated. Results: The operative mortality rate was 2% (2 of 101 patients). Early postoperative patency rates for overall and aortocoronary NT-SV grafts were 98.2% (223 of 227 distal anastomoses) and 98.2% (164 of 167), respectively. The 1- and 3-year patency rates for aortocoronary SV grafts were 94.9% (131 of 138) and 90.6% (58 of 64), respectively. The overall survival rates at 5 and 10 years were 81.7% and 59%, respectively. The cumulative incidence of major adverse cardiac events at 5 and 10 postoperative years was 20.7% and 39%, respectively. Conclusion: The feasibility of using NT-SVs as aortocoronary grafts in CABG was shown in this study, based on the graft patency rates up to 3 years and the mid-term clinical outcomes.