Assessment of the myocardial protective effect of antegrade warm blood cardioplegia by measuring the release of biochemical markers

Intermittent warm blood cardioplegia has been reported as a valuable alternative for myocardial protection in cardiac surgery; however, conflicting experimental data have been published. To assess the clinical effectiveness of intermittent warm cardioplegia, we measured the release of troponin-T (Tn-T), a highly sensitive and specific marker of myocardial damage, and creatine kinase MB isoenzyme (CK-MB), in 12 patients who underwent elective coronary artery bypass grafting (CABG) with antegrade intermittent warm blood cardioplegia (37 degrees C) being the warm group, in comparison with 16 patients who underwent CABG with antegrade intermittent cold blood cardioplegia (4 degrees C) being the cold group. Blood samples were taken to determine the serum concentrations of CK-MB and Tn-T, at the induction of anesthesia, then 3, 6, 12, and 24h after the termination of cardiopulmonary bypass (CPB). The peak increase in serum CK-MB levels, 3h after CPB, was significantly lower in the warm group than in the cold group, at 27.8+/-7.8 IU/l vs. 40.8+/-12.6 IU/l, respectively (P = 0.0042). The serum Tn-T 12 h after CPB was significantly lower in the warm group than in the cold group, at 1.40+/-0.71 ng/ml vs. 2.06+/-0.95 ng/ml, respectively (P = 0.049). In conclusion, intermittent antegrade warm blood cardioplegia showed effective myocardial protection in elective CABG.

Doppler aortic flow pattern in the recovering heart treated by cardiac extracorporeal membrane oxygenation International Society for Artificial Organs

A 39-year-old man was admitted to our hospital because of chest pain and was diagnosed with severe heart failure due to viral myocarditis. Intraaortic balloon pumping (IABP) and cardiac extracorporeal membrane oxygenation (ECMO) were employed. Using Doppler echocardiography, we evaluated the descending aortic blood flow pattern. When cardiac ECMO was initiated from the right femoral artery, a strong backflow of blood generated by the pump was observed in the abdominal aorta because the forward flow from the native heart was weak. Two days later, the blood flow was reversed from the thoracic to abdominal aorta; the natural flow was strengthened because the native heart had improved. The observation of this phenomenon is helpful for determining the recovery of cardiac function under cardiac ECMO support.

Dietary docosahexaenoic acid enhances ferric nitrilotriacetate-induced oxidative damage in mice but not when additional alpha-tocopherol is supplemented

Weaning mice were fed a diet supplemented with beef tallow (BT) or BT plus docosahexaenoic acid (DHA) containing 100 mg alpha-tocopherol/kg (alpha-Toc100) or 500 mg alpha-tocopherol/kg (alpha-Toc500) for 4 wk to modify membrane fatty acid unsaturation, and then were administered ferric nitrilotriacetate (Fe-NTA). The mortality caused by Fe-NTA was higher in the group fed the DHA (alpha-Toc100) diet than in the BT diet groups but the DHA (alpha-Toc500) diet suppressed this increase. Serum and kidney alpha-tocopherol contents were slightly influenced by the dietary fatty acids but not significantly. These results indicate that the increased unsaturation of tissue lipids enhances oxidative damage induced by Fe-NTA in mice fed DHA (alpha-Toc100) but not when additional alpha-tocopherol is supplemented. The apparent discrepancy between the observed enhancement by dietary DHA of oxidative damage and the beneficial effects of dietary DHA on the so-called free radical diseases is discussed in terms of strong bolus oxidative stress and moderate chronic oxidative stress.

Effects of dietary docosahexaenoic acid on surface molecules involved in T cell proliferation

It is known that n-3 polyunsaturated fatty acids (PUFA) such as docosahexaenoic acid (DHA) suppress immunity as compared with n-6 PUFA such as linoleic acid (LA), but the mechanism involved in this phenomenon is still unclear. The present study was designed to assess the effect of dietary DHA on the surface molecules involved in T cell proliferation. Weanling male C57BL/6 mice were divided into four dietary groups that were fed a 10% fat diet for 4 weeks varying in amounts of DHA and LA. As the dietary DHA concentration increased, the surface expression of CD4 and CD8 on splenic T cells decreased, while that of CD28 increased. The surface expression of CD3, however, was invariable in all dietary groups. DNA synthesis of splenic T cells, induced by CD3 crosslinkage with anti-CD3 epsilon monoclonal antibody in the presence of CD28-mediated costimulation, increased as the DHA concentration was elevated. These observations suggest that diets rich in DHA exert some of their immunomodulatory effects by a downregulation of surface expression of CD4 and CD8 and by an upregulation of CD28-mediated costimulatory signal.

Platelet aggregation during cardiopulmonary bypass evaluated by a laser light-scattering method

BACKGROUND

In regard to postoperative bleeding, the most important consequence of cardiopulmonary bypass (CPB) is the loss of aggregability. However, the mechanism of platelet aggregation loss during CPB is unclear. Newly developed particle-counting methods that use light scattering can be used to quantify changes in the number of platelet aggregates of different sizes after application of an aggregating stimulus. Using a light-scattering method, we investigated changes in platelet aggregation during cardiac operation.

METHODS

Nineteen patients undergoing CPB were evaluated. Blood samples were obtained before the operation, 1 hour after initiation of CPB, at the end of CPB, at the end of the operation, and on day 1 after the operation. Platelet aggregation after stimulation by 2.5 micromol/L adenosine diphosphate and 2.0 microg/mL collagen was determined; small (9 to 25 microm), medium (25 to 50 microm), and large (50 to 70 microm) aggregates were counted.

RESULTS

Generation of medium and large aggregates after stimulation with adenosine diphosphate and collagen were significantly decreased with CPB, whereas, in spite of hemodilution, the quantity of the small aggregates was maintained at the elevated level.

CONCLUSIONS

These results reflect the fact that CPB does not affect the first phase of aggregation. It suggests that platelet dysfunction associated with CPB is mainly caused by an inhibition in the development of small aggregates into larger aggregates.

The hypotensive effect of docosahexaenoic acid is associated with the enhanced release of ATP from the caudal artery of aged rats

Fish oils have been shown to lower blood pressure in hypertensive subjects. To determine the mechanism of this hypotensive effect, we examined the effects of docosahexaenoic acid (DHA), one of the (n-3) polyunsaturated fatty acids in fish oil, on blood pressure and on the release of adenyl purines, such as ATP, ADP, AMP and adenosine, from the caudal arteries of aged rats. Aged female Wistar rats (100 wk) were fed a high cholesterol diet and were administered intragastrically ethyl all-cis-4,7,10,13,16,19-docosahexaenoate [300 mg/(kg.d)] for 12 wk (DHA group) or vehicle alone (control group). Compared with the controls, rats supplemented with DHA had significantly greater (10.1%) DHA concentrations in the caudal arteries. This was associated with more total (n-3) arterial fatty acids, a greater unsaturation index of arterial fatty acids, 43.9% lower plasma noradrenaline levels and the repression of the elevation in blood pressure observed with advancing age. The amount of purines released, both spontaneously and in response to noradrenaline, from arterial segments of DHA-supplemented rats was significantly higher than that released from tissues of control rats. Regression analysis revealed significant negative relationships between the total amount of purines released from the artery and the systolic (SBP) and diastolic (DBP) blood pressures. These results suggest that in aged rats, supplementation with DHA alters the membrane fatty acid composition as well as the amount of ATP released from vascular endothelial cells and decreases plasma noradrenaline, and that these factors may ameliorate the rise in blood pressure normally associated with advancing age.

Radical modulation activity of pine cone extracts of Pinus elliottii var. Elliottii

The radical modulation activity of lignins prepared from the cone of Pinus elliottii var. Elliottii was investigated, using ESR spectroscopy. These lignins produced radical(s) under alkaline conditions, and the radical intensity was increased with increasing pH. Lower concentrations of lignins slightly reduced the radical intensity of sodium ascorbate, whereas higher concentrations of lignins enhanced both the radical intensity and cytotoxic activity of sodium ascorbate. Lignins effectively scavenged superoxide anion, produced by hypoxanthine-xanthine oxidase reaction. Elliottii lignins significantly inhibited the human immunodeficiency virus (HIV)-induced cytopathic effect, in similar fashions to other natural, commercial and synthetic lignins. Pretreatment of mice with lignins significantly protected them from the lethal infection with E. coli. Crude alkaline extracts of Elliottii pine cone displayed similar magnitude of activity with lignins. These data further supports the medicinal efficacy of plant extracts.

Usefulness of extracorporeal membrane oxygenation for treatment of fulminant myocarditis and circulatory collapse

Prognosis for fulminant myocarditis with cardiogenic shock refractory to conventional therapy is poor. This report describes mechanical circulatory support with extracorporeal membrane oxygenation as an effective alternative for treating fulminant myocarditis with circulatory collapse.

Successful graft replacement of the descending aorta after an extended reconstruction of the ascending and transverse aorta in a patient with Marfan's syndrome

A 27-year-old man with Marfan's syndrome underwent a total aortic graft replacement in three separate stages. Initially the abdominal aorta was replaced, followed by the ascending aorta and aortic arch, and finally the residual portion. The extensive reconstruction of both the ascending and transverse aorta at the second operation, even though no dissection was present in the aortic arch, reduced the risk of the subsequent operation since the same surgical approach did not have to be used.

Right coronary artery dissection and acute infarction due to blunt trauma: report of a case

Coronary artery dissection occurring after a nonpenetrating chest trauma is extremely rare. We describe herein the case of a 43-year-old man who suffered traumatic myocardial infarction after an intimal tear of the right coronary artery had been inflicted by a horse stepping on his back.

Development of a control algorithm for a rotary blood pump: prediction of recovery from cardiac failure

Under extracorporeal membrane oxygenator (ECMO) support, it is difficult to predict recovery of cardiac function. The authors examined the rotary blood pump function curve and developed a new index of dynamic vascular impedance (DVI) for controlling the ECMO system. The cases of nine patients assisted by ECMO after cardiac surgery were analyzed. The index of DVI was calculated from the pump flow and the pressure difference (delta pressure) between the inlet and outlet of the pump. Seven patients were weaned from support. In the patients with recovery of cardiac function, the index of DVI was high and the delta pressure converged on the specific value. Analysis of the rotary blood pump function curve during ECMO support reflects the pump characteristics and provides data for the management of pump speed. The index of DVI can be used to predict the timing for weaning patients from ECMO support. The authors are developing an automatic control system that uses the index of DVI.

Transventricular mitral valve replacement in a patient with a left ventricular aneurysm: report of a case

Postinfarct left ventricular aneurysm associated with mitral valve regurgitation is resistant to medical treatment and often requires surgical repair. A transventricular approach to the mitral valve in such a patient can enable the surgeon to avoid incision of the right or left atrium, and can provide for safe and reliable surgical intervention. We report herein the case of a patient in whom left ventricular aneurysmectomy and concomitant mitral valve replacement were successfully performed using a transventricular approach via aneurysmectomy.

Effect of replacing a high linoleate oil with a low linoleate, high alpha-linolenate oil, as compared with supplementing EPA or DHA, on reducing lipid mediator production in rat polymorphonuclear leukocytes

The fatty acid composition of rat polymorphonuclear leukocytes (PMN) was modified by diets supplemented with a high linoleate (LA) safflower oil (76% LA), mixtures of eicosapentaenoate (EPA) and safflower oil (EPA(20) containing 20% EPA and 61% LA, EPA(40) containing 40% EPA and 46% LA), mixtures of docosahexaenoate (DHA) and safflower oil (DHA(20) containing 20% DHA and 61% LA, DHA(40) containing 40% DHA and 46% LA) or a high alpha-linolenate (alpha-LNA) perilla oil (57% alpha-LNA and 13% LA), and then lipid mediator production in casein-induced peritoneal PMN were compared. EPA and DHA were relatively ineffective in reducing platelet-activating factor (PAF) production; a statistically significant reduction was observed only in the DHA(40) group. In contrast, perilla oil reduced PAF production by 50% as compared with safflower oil. Arachidonate (AA) in the PAF precursor, 1-alkyl-2-acyl-glycerophosphocholine, was roughly correlated with PAF production, but EPA and DHA in the precursor lipid were relatively unrelated. On the other hand, both PGE2 and LTB4 production correlated positively with AA and negatively with EPA and DHA in PMN phospholipids; EPA tended to be somewhat more effective than DHA in reducing PGE2 and LTB4 formation; the activity of perilla oil was no less than EPA(20). Thus, replacing safflower oil with perilla oil was no less effective than supplementing safflower oil with EPA or DHA (at 40% of total fatty acids) in reducing lipid mediator production in rat PMN.

Effect of dietary docosahexaenoic acid on in vitro thermogenesis and fatty acid compositions of brown adipose tissue

Brown adipose tissue (BAT) is a major organ of nonshivering thermogenesis during cold acclimation, overfeeding, and nonthermal restraint stress. An increased unsaturation of fatty acids of membrane phospholipid in BAT has been shown to be closely associated with an enhanced function of this tissue as reported in other tissues. In the previous study, we found that among fatty acids detected, the n-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) in BAT phospholipid is the only fatty acid that altered concomitantly with a change in the in vitro thermogenic capacity for nonshivering thermogenesis of BAT from cold acclimated and restrained rats. To examine the effect of dietary DHA on fatty acid composition of phospholipid and in vitro BAT thermogenic activity, rats were fed a standard diet supplemented with purified DHA for 4 or 16 weeks. Dietary DHA for 4 or 16 weeks increased DHA level in BAT phospholipid, and it also decreased arachidonic acid. The unsaturation index increased and remained unchanged under DHA feeding for 4 and 16 weeks, respectively. In vitro thermogenic activity of BAT remained unchanged and decreased under dietary DHA for 4 and 16 weeks, respectively. These findings indicate that dietary DHA could increase DHA level in phospholipid of BAT, but it could not improve in vitro BAT thermogenic response.

Growth potential and left ventricular diastolic function in cardiomyoplasty

BACKGROUND

Dynamic cardiomyoplasty is an experimental operation for advanced heart failure. Current clinical results bring the possibility of its application to children. This study was designed to obtain information about the relationship between cardiomyoplasty and growth of the heart.

METHODS

Six beagles, 9 to 10 weeks old, underwent cardiomyoplasty without electric stimulation (cardiomyoplasty group), and another 5 beagles underwent median sternotomy and pericardiotomy (control group). Six months later, weights of hearts, wrapped latissimus dorsi muscles, and unwrapped right latissimus dorsi muscles and pressure-volume relationships were obtained.

RESULTS

Wrapped latissimus dorsi muscles weighed 33 +/- 3 g (mean +/- standard deviation), and unwrapped muscles weighed 68 +/- 5 g. The heart weight was 82 +/- 3 g in the cardiomyoplasty group and 89 +/- 7 g in the control group. Left ventricular maximum elastance was 3.8 +/- 0.8 mm Hg/mL in the cardiomyoplasty group and 3.9 +/- 0.9 mm Hg/mL in the control group. End-diastolic pressure versus end-diastolic volume ratios were 0.52 +/- 0.03 and 0.54 +/- 0.05, respectively. Pathologic examination showed fat infiltration and muscle fiber atrophy in the cardiomyoplasty group.

CONCLUSIONS

The wrapped latissimus dorsi muscle flaps were growing and the diastolic function was not impaired. This indicates a potentially safe clinical application of dynamic cardiomyoplasty for children.

Evaluation of platelet damage in two different centrifugal pumps based on measurements of alpha-granule packing proteins

Mechanical trauma caused by centrifugal pumps is usually evaluated in terms of hemolysis. However, platelet damage caused by centrifugal pumps has not been studied well. We evaluated platelet damage in 2 different centrifugal pumps, the Medtronic BioMedicus BP-80 and the Terumo Capiox, in vitro and compared the results in terms of hemolysis. To evaluate platelet damage, the rate of increase (RI) for beta-thromboglobulin (beta-TG) and platelet factor-4 (PF-4) were measured by enzyme immunoassay. RI was defined as follows: RI for beta-TG is deltabeta-TG/deltaN and RI for PF-4 is deltaPF-4/deltaN where deltabeta-TG is the increase in beta-TG, deltaPF-4 is the increase in PF-4, and deltaN is the increase of the passing number, which is defined in the following equation: N = Qt/V (t, time; V, priming volume; Q, flow rate). Each pump was tested in a mock circuit for 3 h under a flow rate of 5 L/min and a pressure head of 100 mm Hg using fresh human heparinized blood (n = 5). For comparison, the normalized index of hemolysis (NIH) values were calculated for both pumps. The NIH values did not indicate a significant difference between the Capiox and the BP-80 pumps (Capiox vs. BP-80, 0.0021 +/- 0.0004 vs. 0.0034 +/- 0.0007, NS). However, the RI values for beta-TG and PF-4 in the Capiox were significantly lower than in the BP-80 (beta-TG, 0.198 +/- 0.047 vs. 0.376 +/- 0.049; PF-4, 0.080 +/- 0.014 vs. 0.268 +/- 0.043, p < 0.05). In conclusion, although there was no significant difference between the 2 pumps in terms of hemolysis, the Capiox centrifugal pump induced less platelet damage than the BP-80. The results suggest that measurements of RI for beta-TG and PF-4 are more sensitive parameters than NIH values for evaluating blood cell damage.

Platelet protective effect of TAK-029, a novel glycoprotein IIb/IIIa antagonist: an in vitro study

Previous studies have indicated that exposure of fibrinogen receptors associated with the glycoprotein IIb/IIIa complex contributes to platelet loss during cardiopulmonary bypass. TAK-029 is a newly developed reversible, nonpeptide inhibitor of platelet glycoprotein IIb/IIIa receptors. In this study, we tested the platelet preserving effect of TAK-029 in an in vitro model. The methods included the comparison of the release of beta-thromboglobulin (beta-TG) between a TAK-029 group (n = 5) and a control group (n = 5) in a mock circulation under a shear force generated by a centrifugal pump. To evaluate the degree of beta-TG release, deltabeta-TG/deltaT was calculated where deltabeta-TG is the increase in beta-TG and deltaT is the time. The results showed that the value of deltabeta-TG/deltaT in the TAK-029 group was significantly lower than it was in the control group (4.22 +/- 0.27 x 10(2) ng/ml vs. 7.33 +/- 0.66 x 10(2) ng/ml, respectively). In conclusion, TAK-029 reduced the platelet activation under the shear forces of an in vitro model, suggesting that TAK-029 is a potential candidate for platelet protection during cardiopulmonary bypass.

Mechanisms of cardiomyoplasty: comparative effects of adynamic versus dynamic cardiomyoplasty

BACKGROUND

The apparent paradox seen in patients who have undergone dynamic cardiomyoplasty and shown substantial clinical and functional improvements with only modest hemodynamic changes may be due to inappropriate end points chosen for study, a result of incomplete understanding of mechanisms involved. The purpose of this study was to compare the relative role of the passive "girdling effect" and the dynamic "systolic squeezing effect" of the wrapped muscle in cardiomyoplasty.

METHODS

The control group of 6 dogs underwent 4 weeks of rapid pacing (250 beats/min) to induce severe heart failure followed by 8 weeks of observation without rapid pacing. The trajectory of recovery in hemodynamics and cardiac dimensions was followed with echocardiography and Swan-Ganz catheters. In the "adynamic" cardiomyoplasty group (n=4), the left latissimus dorsi muscle was wrapped around the ventricles and allowed to stabilize and mature for 4 weeks. This was followed by rapid pacing and recovery as in the control group. In the "dynamic" cardiomyoplasty group (n=3), the same protocol for the adynamic group was followed except that a synchronizable cardiomyostimulator was attached to the thoracodorsal nerve of the muscle wrap. This allowed the latter to be transformed during the rapid-pacing phase and permitted dynamic squeezing of the muscle wrap to be generated by burst stimulation synchronized with cardiac contraction in a 1:2 ratio.

RESULTS

Baseline data were comparable in all groups prior to rapid pacing. After 4 weeks of rapid pacing, the left ventricular ejection fraction was higher in the adynamic (27.0%+/-3.9%; p < 0.05) and dynamic (33.3%+/-2.3%; p < 0.02) cardiomyoplasty groups compared with controls (18.8%+/-8.3%). Similarly, ventricular dilatation in both systole and diastole was less in the adynamic (51.8+/-8.7 mL, [p < 0.002] and 38.2+/-7.2 mL [p < 0.001], respectively) and dynamic (62.0+/-7.2 [p < 0.02] and 41.3+/-3.5 mL [p < 0.005], respectively) cardiomyoplasty groups compared with controls. In the dynamic group, on and off studies were carried out after cessation of rapid pacing while the heart was still in severe failure, and they demonstrated a systolic squeezing effect in stimulated beats. Only this group recovered fully to baseline after 8 weeks.

CONCLUSIONS

By reducing myocardial stress, both the passive girdling effect and the dynamic systolic squeezing effect have complementary roles in the mechanisms of dynamic cardiomyoplasty.

Saphenous vein graft pseudoaneurysm rupture after coronary artery bypass grafting

An elderly woman underwent coronary artery bypass grafting, which was followed 1 month later by pseudoaneurysmal rupture at the distal anastomosis of a saphenous vein graft. Emergency repair of the suture line dehiscence was made, and the postoperative course was uneventful. Pseudoaneurysm formation of a saphenous vein graft after coronary artery bypass grafting is a rare but potentially lethal complication requiring urgent operative intervention.

Infectious mediastinitis after cardiac operations: computed tomographic findings

BACKGROUND

Infectious mediastinitis after cardiac operations is of great concern to cardiac surgeons because of its poor prognosis. Prompt surgical interventions such as debridement and irrigation are the key to treatment of infectious mediastinitis.

METHODS

We surveyed retrospectively the cases of 722 consecutive cardiac surgery patients at our hospital. Mediastinitis developed in 21 patients after the cardiac operation. We performed computed tomography in 11 of these patients before resternotomy and in 10 patients as the control 2 to 3 weeks after the cardiac operation.

RESULTS

Mediastinal soft tissue swelling was seen in 7 patients, bilateral pleural effusion was found in 9 patients, sternal dehiscence or sternal erosion was observed in 8 patients, and subcutaneous fluid accumulation was found in 7 of the mediastinitis group. Unilateral pleural effusion was seen in 6 and bilateral effusion in 1, and mediastinal soft tissue swelling was seen in 1 patient of the control group.

CONCLUSIONS

Our study showed that mediastinal soft tissue mass combined with bilateral pleural effusion can be a characteristic computed tomography finding in poststernotomy infectious mediastinitis, and that chest computed tomography is more sensitive to detecting sternal dehiscence, sternal erosion, and subcutaneous fluid accumulation.

Recovery from lymphocytopenia and prognosis after adult extracorporeal membrane oxygenation

Extracorporeal circulation severely impairs the host immune system. Also decreases in circulatory lymphocytes correlate with greater degrees of surgical damage. In this study, the pattern of recovery from lymphocytopenia after extracorporeal membrane oxygenation was retrospectively evaluated from a prognostic viewpoint. The results showed that the circulatory lymphocyte count of survivors returned to normal levels within 5 days after their being weaned from extracorporeal membrane oxygenation, while the circulatory lymphocyte count of nonsurvivors remained at low levels. Because it is easy to measure the number of peripheral lymphocytes, the changing pattern of the circulatory lymphocytes might be a simple and reliable prognostic factor after extracorporeal membrane oxygenation.