Jae Seung Jung

Pulsatile versus nonpulsatile flow to maintain the equivalent coronary blood flow in the fibrillating heart.

How much flow is required by a nonpulsatile pump to match the coronary blood flow equivalent to that of pulsatile pump? A cardiopulmonary bypass circuit from the right atrium to the ascending aorta was constructed in a ventricular fibrillation model using 13 Yorkshire swine. The animals were randomly divided into two groups: CONTROL (pulsatile T-PLS, n = 7) or EXPERIMENTAL (nonpulsatile Biopump, n = 6). The hemodynamic data at mid-LAD level was measured with a flow meter at baseline and every 20 minutes after pump flow initiation. The pump flow was started from 2 L/min in both groups (67 ± 8 in CONTROL and 70 ± 9 ml/kg/min in EXPERIMENTAL; p = NS), and the pump flow of the EXPERIMENTAL group was increased to match the coronary flow of the CONTROL group. To maintain mean velocity and flow in the LAD, the EXPERIMENTAL group required significantly higher pump flow at 20, 40, and 60 minutes (84 ± 17 vs. 67 ± 8, 87 ± 24 vs. 67 ± 8, 85 ± 18 vs. 67 ± 8 ml/kg/min, respectively, p < 0.05). The LAD diameter was substantially smaller in the CONTROL group and the resistance index was significantly lower in the CONTROL group at 80 minutes and 120 minutes after bypass (0.56 ± 0.26 vs. 0.87 ± 0.20 and 0.61 ± 0.23 vs. 0.90 ± 0.06; p < 0.05). In conclusion, we found that the nonpulsatile pump may require 25%–28% higher pump flow than the pulsatile pump to maintain equivalent coronary blood flow.

Comparison of Extracorporeal Cardiopulmonary Resuscitation with Conventional Cardiopulmonary Resuscitation: Is Extracorporeal Cardiopulmonary Resuscitation Beneficial?

Background With improvements in cardiopulmonary resuscitation (CPR) techniques, the quality and the effectiveness of CPR have been established; nevertheless, the survival rate after cardiac arrest still remains poor. Recently, many reports have shown good outcomes in cases where extracorporeal membrane oxygenation (ECMO) was used during prolonged CPR. Accordingly, we attempted to evaluate the impact of extracorporeal cardiopulmonary resuscitation (ECPR) on the survival of patients who experienced a prolonged cardiac arrest and compared it with that of conventional CPR (CCPR). Methods Between March 2009 and April 2014, CPR, including both in-hospital and out-of-hospital CPR, was carried out in 955 patients. The ECPR group, counted from the start of the ECPR program in March 2010, included 81 patients in total, and the CCPR group consisted of 874 patients. All data were retrospectively collected from the patients’ medical records. Results The return of spontaneous circulation (ROSC) rate was 2.24 times better in CPR of in-hospital cardiac arrest (IHCA) patients than in CPR of out-of-hospital CA (OHCA) patients (p=0.0012). For every 1-minute increase in the CPR duration, the ROSC rate decreased by 1% (p=0.0228). Further, for every 10-year decrease in the age, the rate of survival discharge increased by 31%. The CPR of IHCA patients showed a 2.49 times higher survival discharge rate than the CPR of OHCA patients (p=0.03). For every 1-minute increase in the CPR duration, the rate of survival discharge was decreased by 4%. ECPR showed superiority in terms of the survival discharge in the univariate analysis, although with no statistical significance in the multivariate analysis. Conclusion The survival discharge rate of the ECPR group was comparable to that of the CCPR group. As the CPR duration increased, the survival discharge and the ROSC rate decreased. Therefore, a continuous effort to reduce the time for the decision of ECMO initiation and ECMO team activation is necessary, particularly during the CPR of relatively young patients and IHCA patients.

Popliteal Artery Entrapment Syndrome: A Case with Bilateral Different Types

Popliteal artery entrapment syndrome (PAES) is a non-artherosclerotic cause of claudication and acute ischemia of the legs in young athletic individuals. It is classified in terms of the abnormal anatomical relationship between the popliteal artery and surrounding structures. All types of PAES have the same pathophysiology. Repetitive arterial compression by surrounding structures causes progressive vascular injury. Bilateral PAES is reported in about 30% of cases. Bilateral PAES is usually of the same type in each artery; exceptions are rare. We report a case of a young athletic patient who suffered bilateral PAES of two different types.

The Effect of Fluid Viscosity on the Hemodynamic Energy Changes During Operation of the Pulsatile Ventricular Assist Device

Blood viscosity during operation of ventricular assist device (VAD) can be changed by various conditions such as anemia. It is known generally that the blood viscosity can affect vascular resistance and lead to change of blood flow. In this study, the effect of fluid viscosity variation on hemodynamic energy was evaluated with a pulsatile blood pump in a mock system. Six solutions were used for experiments, which were composed of water and glycerin and had different viscosities of 2, 2.5, 3, 3.5, 4, and 4.5 cP. The hemodynamic energy at the outlet cannula was measured. Experimental results showed that mean pressure was increased in accordance with the viscosity increase. When the viscosity increased, the mean pressure was also increased. However, the flow was decreased according to the viscosity increase. Energy equivalent pressure value was increased according to the viscosity-induced pressure rise; however, surplus hemodynamic energy value did not show any apparent changing trend. The hemodynamic energy made by the pulsatile VAD was affected by the viscosity of the circulating fluid.

Measurement of hemodynamic energy at different vessels in an adult swine model

Extra hemodynamic energy is one of the major benefits of pulsatile flow, improving blood flow to vital organs. But most (80%) of the hemodynamic energy generated from pulsatile flow is damped by the extracorporeal circuit. Most models devised to minimize hemodynamic energy loss have been in vitro pediatric models. The purpose of this study was to measure hemodynamic energy in different vessels of different organs with an in vivo adult swine model. An extracorporeal circuit was constructed for seven Yorkshire swine using a pulsatile pump (Twin-Pulse Life Support). The mean arterial pressure (MAP), energy equivalent pressure (EEP), and surplus hemodynamic energy (SHE) at the renal artery, carotid artery, aortic cannula site, and postoxygenator site were measured simultaneously before starting the pump and at the pump rates of 25, 35, and 45 bpm. The MAP of the renal or carotid artery was 40.0%–51.2% of the postoxygenator site. The EEP and SHE of both arteries were 11.6%–13.0% and 5.5%–7.4% of the postoxygenator site, respectively. The MAP and EEP of both arteries after starting the pump were lower than at baseline. The SHE of the renal artery after starting the pump was significantly higher than at baseline. The SHE of the carotid artery increased substantially after starting the pump although not statistically significantly. There was a significant hemodynamic energy loss in both arterial sites compared with the postoxygenator site. Also, a difference in hemodynamic energy loss was observed in vessel-to-vessel or vessel-to-circuit site comparison. This difference creates a bias in studying pulsatility and its effects. Therefore, the measurement method of hemodynamic energy must be standardized and the measurement site clarified to yield accurate study results.

Effects of Angiotensin-II Receptor Blocker on Inhibition of Thrombogenicity in a Canine Atrial Fibrillation Model

Background and Objectives Angiotensin-II receptor blockers (ARBs) are known to reduce the development of atrial fibrillation (AF) through reverse-remodeling. However, the effect of ARBs on thrombogenicity in AF remains unknown. Materials and Methods Twelve dogs were assigned to control (n=4), ARB (candesartan cilexitil 10 mg/kg/day p.o., 12 weeks; n=4), or sham (n=4) groups. Sustained AF was induced by rapid atrial pacing. Both arterial and venous serum levels of tissue inhibitor of matrix metalloproteinase-1, von Willebrand factor, P-selectin, and vascular cell adhesion molecule-1 (VCAM-1) were measured at baseline and during AF (0, 4, and 12 weeks) with enzyme-linked immunosorbent assay. Biopsies from both atria including the appendages were performed to semi-quantitatively assess endocardial and myocardial fibrosis after 12 weeks. Results The serum levels of bio-markers were not significantly different at baseline or during AF between the control and the candesartan groups. The levels were not significantly different over time, but there was a trend toward a decrease in arterial VCAM-1 from 4 to 12 weeks in the candesartan group compared to the control group. The grades of endocardial fibrosis after 12 weeks but not those of myocardial fibrosis were slightly reduced in the candesartan group compared to the control group. Conclusion This study did not show that the ARB candesartan significantly reverses thrombogenicity or fibrosis during AF. Future studies using a larger number of subjects are warranted to determine the therapeutic effect of renin-angiotensin-aldosterone system blockade on prothrombogenic processes in AF.

Porcine dermal collagen (permacol) for sternal reconstruction.

In chest wall reconstruction after wide chest wall resection, the use of a musculocutaneous flap or prosthetic materials is inevitable for maintaining thoracic movement and a closed pleural cavity. We report a case of a 63-year-old male with a large invasive thymic carcinoma in the anterior mediastinum. The mass measured 6.8 cm and involved the sternum, left side of the parasternal area, ribs, and intercostal muscles. The patient underwent subtotal sternectomy, radical thymectomy, and reconstruction with biological mesh (Permacol). Successful chest wall reconstruction without any other complications was achieved, demonstrating the effectiveness of Permacol.

Thoracic duct embolization with lipiodol for chylothorax due to thoracic endovascular aortic repair with debranching procedure

Chylothorax is a rare postoperative complication of a thoracic surgical procedure. Here, we report a case of chylothorax after thoracic endovascular aortic repair with debranching for the distal arch aneurysm of the aorta. First, the patient was treated by a medical method (nil per os, fat-free diet, and octreotide), but this method failed. The patient strongly refused surgical treatment. Therefore, we tried to occlude the thoracic duct by lymphangiography Lipiodol, and this line of treatment was successful.

Transient limb ischaemia during extracorporeal membrane oxygenation: inappropriate venous cannula location

Percutaneous placement of extracorporeal membrane oxygenation (ECMO) cannulas has many benefits. However, limb ischaemia still remains as an unresolved problem. We experienced an interesting case of limb ischaemia that was caused by external compression of the superficial femoral artery by the venous cannula. A 73-year old woman underwent veno-arterial ECMO due to sudden cardiac arrest with percutaneous femoral cannulations at the right common femoral vein and the left common femoral artery. Three hours after cannulation, the patients right lower extremity was cool and pale, and the arterial pulses of dorsalis pedis artery and posterior tibial artery were not palpable. After confirming the absence of blood flow at the peripheral arteries of the lower extremity through colour Doppler ultrasonography, we explored the right femoral cannulation area. The venous cannula, which was approaching the common femoral vein from the lateral side, was passing between the bifurcation area of the superficial and deep femoral arteries, directly compressing the superficial femoral artery from beneath. We rapidly removed the inappropriately placed venous cannula, and then re-inserted it at another location of the femoral vein. Although it was an unusual case where arterial occlusion was due to external compression of the venous cannula, successful limb reperfusion could be obtained through rapid identification and correction.

Current Status of Off-pump Coronary Artery Bypass Grafting in Patients with Multiple Coronary Artery Disease Compared with On-pump Coronary Artery Bypass Grafting: The Korean National Cohort Study

Background Despite advance in off‐pump coronary artery bypass (OPCAB) grafting, there are large debating issues regarding survival benefit between OPCAB and on‐pump coronary artery bypass grafting (CABG). The aim of this study is to address appropriateness of OPCAB approach in patients with ischemic heart disease having multiple vessels using South Korea national cohort data. Methods To evaluate the safety and efficacy of OPCAB, we accessed all causes of death, late repeat revascularization, hospitalization for cerebrovascular accident (CVA), and new renal replacement therapy in patients who underwent isolated CABG with multiple grafting (≥2 grafts) and who were registered in the Korean Health Insurance Review and Assessment Service Database between April 2011 and September 2014. Results OPCAB was performed in 4,692 patients and on‐pump CABG in 2,999 patients from 82 hospitals in South Korea. On multivariable analysis, on‐pump CABG was associated with a significantly higher adjusted risk of overall all‐cause death (hazard ratio [HR]: 1.876, 95% confidence interval [CI]: 1.587‐2.216, p < 0.001) and initiation of new renal replacement therapy (HR: 1.618, 95% CI: 1.124‐2.331, p = 0.009). However, we observed no significant difference in repeat revascularization and hospitalization for CVA between the two groups. In propensity score matching, matched patients (2,940 pairs) showed results similar to multivariable analysis that on‐pump CABG was associated with a higher overall mortality and initiation of new renal replacement therapy (p < 0.001). Conclusion In this study, we found that OPCAB was associated with better survival rates and renal preservation compared with on‐pump CABG.