[Abdominal complications in patients with implanted mechanical cardiac support]

Patients with implanted mechanical cardiac support are exposed to the risk of various complications in the early postoperative period. Although thromboembolic and bleeding events occur most frequently in these patients, we cannot disregard other complications that can have a significant impact on the further development of the implanted patients condition. These include abdominal complications. Literature data show clearly that mortality in implanted patients who developed an abdominal complication is significantly higher than that in patients without postoperative abdominal complications.

[Cardiosurgical procedures in patients refusing blood transfusions: IKEM outcomes]

INTRODUCTION

Jehovah's Witnesses who require cardiac operation represent a specific challenge to the physicians. Members of this faith will not accept blood or blood products under any circumstances on the basis of religious grounds. Nevertheless cardiac operations belong to surgical interventions with potential severe bleeding and necessity of blood transfusions.

THE AIM OF THE STUDY

The aim of this retrospective study was to analyze clinical data, operative and postoperative courses of patients operated at IKEM who refused blood transfusions.

METHODS AND RESULTS

From January 1995 to August 2010, 73 Jehovah's Witnesses ranging in age from 19 to 82 years underwent cardiac surgery at our institute. Aortocoronary bypass were performed in 34 patients, valve surgery in 25 patients, 6 patients underwent concomitant aortocoronary bypass and valve surgery, 2 patients underwent aortocoronary bypass and resection of the left ventricle aneurysm and 2 patients underwent atrial septal defect repair and tricuspid valve anuloplasty. Ventricular septal sefect repair, atrial septal defect repair, Cor Cap device implantation and left ventricular epicardial electrodes implantation were performed in the other patients. Early 30-days mortality was 2.8 % (2 patients).

CONCLUSION

We can conclude that cardiac surgery in Jehovah's Witnesses can be performed safety without blood transfusion and belongs to standard operating procedures at our institution.

[Outcomes of combined mitral valve repair surgery and aortic valve replacement in IKEM Praha]

AIM OF THE STUDY

We retrospectively analyzed long-term outcome of concomitant mitral valve repair and aortic valve replacement.

METHODS

From 1996 to 2009 we performed mitral valve plasty with aortic valve replacement in 50 patients. Clinical and echocardiographic data were obtained from computer database and hospital records. Missing data were obtained through mailed questionnaire. We evaluated hospital mortality, long-term survival, thromboembolic and hemorrhagic complications and TR of 3+ on follow up echocardiography.

RESULTS

Four patients who had previously undergone aortic valve surgery were excluded from the study. Aortic valve pathology was stenosis in 21 patients, regurgitation in 20 and 4 patients presented with mixed aortic disease. The etiology of mitral regurgitation was rheumatic in 6, non-rheumatic in 31 and infective in 6 patients. Aortic valve was replaced with mechanical prosthesis in 22 (mean age 59) and tissue prosthesis in 24 (mean age 71) patients. Additional surgical procedure was performed in 26 patients. Follow-up was 94% complete, with a mean duration of 51 months. Hospital mortality was 13%. Two and five year survival was 79% and 64% respectively. We noted one case of retroperitoneal hemorrhage and one stroke. We recorded 9 (19.6%) patients with residual TR of more than 3+ grade on follow up echocardiography. Out of 9 patients with residual TR, 3 were operated for rheumatic and 6 for non-rheumatic mitral valve disease. One patients underwent successful mitral valve replacement with mechanical prosthesis, 3 died and 5 are treated expectantly.

CONCLUSION

We conclude that concomitant mitral valve repair with aortic valve replacement has high hospital mortality, excellent long-term survival and low complication rate. The durability of mitral valve repair in patients with rheumatic mitral valve disease is limited and replacement, rather that repair should be considered in this patient group.

[Vascular complications in transcatheter aortic valve implantation in IKEM]

AIM

Retrograde transfemoral arterial approach is the most common technique of transcatheter aortic valve implantation. Diameter of available catheters is the limiting factor for percutaneous usage. We currently use 18 French third generation Medtronic Core Valve system. We retrospectively analyzed procedure related complications in our patient cohort.

MATERIAL AND METHODS

Transcatheter aortic vale implantation with 18 French Medtronic Core Valve was performed in 35 patients (23 females, 12 males) in between 12/2008 and 7/2010.

RESULTS

Mean age was 81.4 +/- 6.1 years (range 69-92), mean logistics EuroSCORE was 19.3 +/- 8.9% (range 8-42), mean aortic valve gradient 59.8 +/- 19.8 mm Hg (range 30-86 mm Hg (mean indexed aortic valve area 0.37 +/- 0.11 cm.

Late effect of early hypoxic disturbance in the rat heart: gender differences

Perinatal hypoxemia may have serious long-term effects on the adult cardiovascular system and may lead to sex-dependent changes in cardiac tolerance to acute ischemia in adult life. The aim of the study was to answer the question whether gonadectomy of the male and female rats in the early phase of ontogenetic development affects the late effect of perinatal hypoxia. Pregnant Wistar rats were placed into a normobaric hypoxic chamber (12 % O(2)) 7 days before the expected date of delivery. Newborn pups were kept in the chamber with their mothers for another 5 days after birth. After hypoxic exposure all animals were kept for 3 months in room air. Some of the pups were gonadectomized right after removal from the hypoxic chamber. Ventricular arrhythmias were assessed on isolated perfused hearts. Castration did not influence arrhythmogenesis in the adult normoxic or perinatally hypoxic female hearts. Nevertheless, the number of arrhythmias was decreased in perinatally hypoxic gonadectomized males. In conclusion, we have shown that perinatal normobaric hypoxia increased cardiac tolerance to acute ischemia in adult male rats; however, it had no late effect in females. Gonadectomy did not affect arrhythmogenesis in both normoxic and hypoxic female hearts, whereas in males significantly decreased the number of arrhythmias.

[Management of deep device related infection in patient implanted with mechanical cardiac support device using V.A.C. system]

Infection remains the most significant cause of morbidity and mortality in pacients implanted with mechanical circulatory support devices (MCSD), reaching prevalence of 40-60% according various authors. Successful treatment of the whole spectrum of infectious complications is the basic determinant in archieving good results in MCSD patients. The treatment involves standard surgical procedures, as well as the use of vacuum assisted closure (V.A.C.) therapy in the last few years. We demonstrate successful management of deep device related infection using V.A.C therapy in a patient with MCSD, giving him the opportunity to heart transplantation, and thereafter successful treatment of poststernotomy mediastinitis in this imunosupressed pacient after heart transplantation.

[Transmyocardial laser revascularization]

AIM OF THE STUDY

The study looked at our results with transmyocardial laser revascularization. We also tried to ascertain the role of TMLR in current cardiothoracic surgical practice.

METHODS

Twenty patients underwent TMLR at IKEM Praha in a period from 1999 to 2007. Patients were categorized into two separate groups. The first included patients who had TMLR as a single procedure. Second group comprised patients who underwent combined TMLR and direct bypass revascularization. Outcome measures were reduction of angina, improvements in exercise tolerance and left ventricular systolic function.

RESULTS

Improvement in CCS classification of two and more classes has been achieved in almost half the patients who underwent TMLR combined with CABG, but only in 20% of patients after isolated TMLR. There was no change in left ventricular systolic function either in group of patients after TMLR or in group with hybrid procedure. There was also no change detected in myocardial perfusion in thallium scintigraphy studies.

CONCLUSION

The study confirmed that TMLR has minimal perioperative complication rate and is safe. On the other hand our results failed to demonstrate any significant improvement in quality of life following TMLR. In our opinion TMLR should be reserved for symptomatic patients in CCS IV class when all other conventional treatment options have been exhausted.

Effect of acute and chronic simvastatin treatment on post-ischemic contractile dysfunction in isolated rat heart

Statins are powerful lipid-lowering drugs, widely used in patients with hyperlipidemia and coronary artery disease. It was found, however, that statins appear to have a pleiotropic effect beyond their lipid-lowering ability. They exert anti-inflammatory, antithrombotic and antioxidant effects, increase nitric oxide production and improve endothelial dysfunction. The aim of our study was to examine the effect of chronic and acute treatment with simvastatin on the contractile function of the isolated perfused rat heart after ischemia/reperfusion injury. Contractile function was measured on isolated rat hearts, perfused according to Langendorff under constant pressure. The hearts were subjected to 20 min of global ischemia, followed by 40 min of reperfusion. To investigate the acute effect, simvastatin at a concentration of 10 micromol/l was added to the perfusion solution during reperfusion. In chronic experiments the rats were fed simvastatin at a concentration of 10 mg/kg for two weeks before the measurement of the contractile function. Acute simvastatin administration significantly increased reparation of the peak of pressure development [(+dP/dt)(max)] (52.9+/-8.2 %) after global ischemia, as compared with the control group (28.8+/-5.2 %). Similar differences were also observed in the time course of the recovery of [(+dP/dt)(max)]. Chronic simvastatin was without any protective effect. Our results reveal that the acute administration of simvastatin during reperfusion, unlike the chronic treatment, significantly reduced contractile dysfunction induced by ischemia/reperfusion injury. This supports the idea of possible cardioprotective effect of statin administration in the first-line therapy of the acute coronary syndrome.

Tolerance to acute ischemia in adult male and female spontaneously hypertensive rats

Clinical and experimental studies have repeatedly indicated that overloaded hearts have a higher vulnerability to ischemia/reperfusion injury. The aim of the present study was to answer the question whether the degree of tolerance to oxygen deprivation in hearts of spontaneously hypertensive rats (SHR) may be sex-dependent. For this purpose, adult SHR and their normotensive control Wistar Kyoto (WKY) rats were used. The isolated hearts were perfused according to Langendorff at constant pressure (proportionally adjusted to the blood pressure in vivo). Recovery of contractile parameters (left ventricular systolic, diastolic and developed pressure as well as the peak rate of developed pressure) was measured during reperfusion after 20 min of global no-flow ischemia in 5 min intervals. Mean arterial blood pressure was measured by direct puncture of carotid artery under light ether anesthesia in a separate group of animals. The degree of hypertension was comparable in both sexes of SHR. The recovery of contractile functions in SHR males and females was significantly lower than in WKY rats during the whole investigated period. There was no sex difference in the recovery of WKY animals; on the other hand, the recovery was significantly better in SHR females than in SHR males. It may be concluded that the hearts of female SHR are more resistant to ischemia/reperfusion injury as compared with male SHR. This fact could have important clinical implications for the treatment of cardiovascular disease in women.

Effects of melatonin on ischemia and reperfusion injury of the rat heart

Effects of melatonin on various manifestations of ischemia/reperfusion injury of the isolated perfused rat heart were examined. Ischemia- and reperfusion-induced ventricular arrhythmias were studied under constant flow in hearts subjected to 10, 15 or 25 min of regional ischemia (induced by LAD coronary artery occlusion) and 10-min reperfusion. Melatonin was added to the perfusion medium 5 min before ischemia at concentrations of 10 micromol/l or 10 nmol/l and was present throughout the experiment. Recovery of the contractile function was evaluated under constant perfusion pressure after 20-min global ischemia followed by 40-min reperfusion. Hearts were treated with melatonin at a high concentration (10 micromol/l) either 5 min before ischemia only (M1) or 5 min before ischemia and during reperfusion (M2) or only during reperfusion (M3). At the high concentration, melatonin significantly reduced the incidence of reperfusion-induced ventricular fibrillation and decreased arrhythmia score (10% and 2.2+/-0.3, respectively) as compared with the corresponding untreated group (62% and 4.1+/-0.3, respectively); the low concentration had no effect. This substance did not affect the incidence and severity of ischemic arrhythmias. Melatonin (M2, M3) significantly improved the recovery of the contractile function as compared with the untreated group; this protection did not appear if melatonin was absent in the medium during reperfusion (Ml). Our results show that melatonin, in accordance with its potent antioxidant properties, effectively protects the rat heart against injury associated with reperfusion. It appears unlikely that melatonin is cardioprotective at physiological concentrations.

Effects of adaptation to intermittent high altitude hypoxia on ischemic ventricular arrhythmias in rats

We compared the effects of adaptation to intermittent high altitude (IHA) hypoxia of various degree and duration on ischemia-induced ventricular arrhythmias in rats. The animals were exposed to either relatively moderate hypoxia of 5000 m (4 or 8 h/day, 2-3 or 5-6 weeks) or severe hypoxia of 7000 m (8 h/day, 5-6 weeks). Ventricular arrhythmias induced by coronary artery occlusion were assessed in isolated buffer-perfused hearts or open-chest animals. In the isolated hearts, both antiarrhythmic and proarrhythmic effects were demonstrated depending on the degree and duration of hypoxic exposure. Whereas the adaptation to 5000 m for 4 h/day decreased the total number of premature ventricular complexes (PVCs), extending the daily exposure to 8 h and/or increasing the altitude to 7000 m led to opposite effects. On the contrary, the open-chest rats adapted to IHA hypoxia exhibited an increased tolerance to arrhythmias that was even more pronounced at the higher altitude. The distribution of PVCs over the ischemic period was not altered by any protocol of adaptation. It may be concluded that adaptation to IHA hypoxia is associated with enhanced tolerance of the rat heart to ischemic arrhythmias unless its severity exceeds a certain upper limit. The opposite effects of moderate and severe hypoxia on the isolated hearts cannot be explained by differences in the occluded zone size, heart rate or degree of myocardial fibrosis. The proarrhythmic effect of severe hypoxia may be related to a moderate left ventricular hypertrophy (27 %), which was present in rats adapted to 7000 m but not in those adapted to 5000 m. This adverse effect can be overcome by an unknown protective mechanism(s) that is absent in the isolated hearts.