Vol 45, No 3 (2017)

The problem of myocardial protection in cardiac surgery is a challenge due to an increased number of interventions and severity of their complications related to the patient's status, pathophysiology of the artificial circulation and the used techniques for replacement of vital functions. Oxidative stress and formation of active oxygen species, as a consequence of the above mentioned processes, may result in systemic injury, such as acute heart failure, central nervous system dysfunction and acute renal injury. Short ischemic episodes before prolonged hypoxia with subsequent reperfusion can decrease cardiomyocyte injury. This phenomenon has been referred to as ischemic preconditioning. A similar effect is caused by inhalation anesthetics. Experimental and clinical data on anesthetic preconditioning suggest that inhalation anesthesia with halogen-containing agents may be used as a method to protect the myocardium from damage by active oxygen species produced during the periods of oxidative stress in cardiac surgery. Studies analyzed in this review have shown benefits of inhalation anesthetics, compared to total intravenous anesthesia, such as effective cardiac protection and, what is most important, in potential reduction of mortality after coronary bypass grafting. The level of evidence for the effects of anesthetic preconditioning on long-term mortality in these studies was not high enough; therefore, a large multicenter randomized controlled trial is needed to confirm these results.

Background: Timely diagnosis of complex and critical congenital heart defects in neonates can help to avoid fatal complications of their natural history and to establish correct treatment strategies. Therefore, easily available and inexpensive screening methods for their routine diagnostics are important.

Aim: To demonstrate the role of pulse oximetry in the diagnosis of complex and critical congenital heart defects.

Materials and methods: Forty six neonates aged from 1 to 27 days with congenital heart defects, diagnosed after birth, were included into the study. Their diagnoses were verified by expert echocardiography performed after positive pulse oximetry test or due to unexplainable oxygen dependency and/or clinical manifestation of severe heart failure. The pulse oximetry test was considered positive with SaO2 < 95% in any extremity and the difference between the right hand and foot of above 3%.

Results: The pulse oximetry test was positive in all neonates with transposition of the great arteries (n = 5), hypoplastic left heart syndrome (n = 6), total anomalous pulmonary venous collection (n = 2), common arterial trunk (n = 3), pulmonary artery atresia with ventricular septum defect (n = 1). The pulse oximetry test was non-informative in those with obstructive abnormalities of the left heart, such as aortic valve stenosis and aortic coarctation.

Conclusion: The pulse oximetry test can be used for routine screening for complex and critical congenital heart defects in neonates.

Rationale: Ageing of population results in an increase in number of aortocoronary bypass interventions in patients with ischemic heart disease aged 65 years and above. This patient group has an increased risk of complications related to systemic inflammatory response to surgical revascularization of the myocardium by on- pump coronary artery bypass (ONCAB). The off-pump coronary artery bypass (OPCAB) enables to avoid complications related to cardiopulmonary bypass; however, there is no consensus on this technique and no clinical guidelines have been developed.

Aim: To evaluate short-term results of surgical treatment of elderly patients with ischemic heart disease after OPCAB and after ONCAB.

Materials and methods: We performed a retrospective analysis of 61 patients aged above 60 years with multivessel coronary artery disease. The patients from group 1 (n = 31, mean age 72.2 ± 7.3 years) underwent OPCAB, whereas the patients from group 2 (n = 30, mean age 69.3 ± 7.7 years) underwent ONCAB and pharmaco-cold cardioplegia.

Results: In the patient group who had underwent OPCAB, there was a significant decrease in the duration of the surgery (4.15 ± 1.2 vs 4.53 ± 1.3 h, p < 0.05), reduction of the duration of mechanical ventilation (11.8 ± 2.3 vs 15.3 ± 1.4 h, p < 0.05), and the number of the transfused RBC doses (0.36 ± 0.9 vs 2.5 ± 1.1 U, p < 0.05). In the early postoperative period, there was a significant difference in the blood loss volume within the 1st day (280 ± 190 mL in group 1 and 359 ± 270 mL in group 2, p < 0.05). The group 1 patients showed a reduction in frequency of heart arrhythmia (4 (12.9%) vs 11 (36.5%) patients, p < 0.05), shorter duration of stay in the resuscitation unit (1.09 ± 0.3 vs 1.46 ± 0.8 days, p < 0.05) and in the department of cardiac surgery (5.06 ± 0.8 vs 7.3 ± 1.1 days, p < 0.05).

Conclusion: In the elderly patients, OPCAB could be the intervention of choice allowing for an improvement of short-term postoperative outcomes.

Rationale: Carotid endarterectomy is a surgical procedure to prevent acute ischemic cerebrovascular accidents. Neurologic complications can occur after surgery. Multidetector computed tomography (MDCT) is used for their diagnosis in severely ill patients.

Aim: To evaluate the potential of MDCT in the diagnosis of neurologic complications after carotid endarterectomy.

Materials and methods: We analyzed the results of radiologic assessments in 15 patients with early postoperative neurologic complications which occurred after surgery for internal carotid artery occlusion (595 patients underwent surgery). In stable patients, brain magnetic resonance imaging (MRI) was performed (T1, T2, FLAIR, DWI modes) with non-contrast MR angiography. In critically ill patients, brain computed tomography, computed tomographic angiography and perfusion computed tomography were performed.

Results: Ischemic neurologic complications were found in 11 patients. One patient had no clinical manifestation of an ischemic stroke, and acute stage signs were found in his routine brain MDCT. In 9 patients with acute brain ischemia, MDCT (n = 6) and MRI (n = 3) results were specific for this diagnosis, with no diagnostic problems. There were problems with the diagnosis of the hyperacute ischemia in 1 patient. In this patient, the complication occurred against a background of abnormal carotid blood flow before surgery, therefore, differential diagnosis between the hyperperfusion syndrome on the intervention side and the hyperacute phase of ischemic insult on the opposite side was performed. Hyperperfusion syndrome and hemorrhagic strokes were observed in 4 patients.

Conclusion: The most difficult for diagnosis by MDCT is the hyperacute phase of brain ischemia. Further studies are necessary in the area of diagnosis of postoperative complications, with the search for potential specific diagnostic criteria.

Rationale: Endovascular implantation may lead to mechanical injury of the vessel walls, their inflammation and subsequent formation of a thrombus in the stented portion of the vessel, as well as to endothelial growth and restenosis. Intimal injury changes the potential of the damaged area from negative to positive.

Aim: To demonstrate the efficacy of corrective negative charge on the stent surface after its endovascular implantation in the reduction of the risk of vessel thrombosis and restenosis.

Materials and methods: With a terminal element technique we created a model for distribution of electrostatic potentials in a healthy and in a partially injured vessel, as well as in a vessel with a negatively charged electret stent. Trials of experimental and serial stents in animals were performed with stent placement into the pig neck arteries with subsequent (at day 21) histological examination of the areas of stent placement. Morphological abnormalities and vessel wall reactions after endovascular carotid stent implantation, such as clot formation and endothelial reaction were assessed.

Results: Negatively charged electret cover of the stent produces corrective electrostatic field to prevent thrombus formation and vascular intima reaction with subsequent restenosis. The use of the stent with negatively charged electret cover ensures a significant reduction of the risk for positive potential inside the injured vessel, thereby dramatically reducing the risk of vessel thrombosis and restenosis. After placement of stents with negatively charged electret cover to animals, there was very mild proliferation of endothelial cells of the vessel wall neointima, compared to that after placement of the reference stents; no thrombus formation was observed. If the reference uncovered stents were placed, there was a dramatic narrowing of the arterial lumen due to proliferation of endothelial neointimal cells, as well as full thrombotic closure of the vessel.

Conclusion: The suggested technology allows for improvement of endovascular stent placement, for reduction of the risk of thrombosis and restenosis after endovascular interventions aimed at revascularization of arterial stenosis.

Rationale: More than half of patients with chronic heart failure have a preserved left ventricular ejection fraction. It has been found that sudden cardiac death is more frequent in this patient category. A reliable and easily available marker is needed that would predict the death outcome with a high probability. The use of the late ventricular potentials for this purpose could be reasonable.

Aim: To assess the prevalence of the late ventricular potential and their association with the structural and functional parameters of the myocardium in patients with early stages of chronic heart failure with preserved ejection fraction.

Materials and methods: We examined 77 patients with chronic heart failure (grade I to IIА, functional class I to III) with preserved ejection fraction (> 50%), aged 47 to 77 years (mean ± SD, 59.7 ± 7.8 years). Echocardiography (SonoScape 8000 and Vivid 3) at М-, В- and Doppler modes was performed in all patients. Ventricular ectopic activity and late ventricular potentials were registered during 24- hour ECG monitoring (Cardiotekhnika, INKART, St. Petersburg).

Results: Late ventricular potentials were found in 13% (10 of 77) of patients. The following correlations were found in patients with concentric hypertrophy (n = 53): between the duration of the filtered QRS (TotORSF) and the left ventricular end diastolic diameter (r = 0.27, p = 0.049), TotORSF and the interventricular septum thickness (r = 0.28, p = 0.04), TotORSF and the left ventricular myocardial mass (r = 0.35, p = 0.01), mean square magnitude of fluctuations within the last 40 ms of ORS (RMS40) and the left ventricular end diastolic diameter (r = -0.42, p < 0.01), RMS40 and the left ventricular end-systolic diameter (r = -0.37, p < 0.01). In the patients with eccentric hypertrophy (n = 14), the following correlations were found: between RMS40 and the left ventricular myocardial mass index (r = -0.77, p < 0.01), between duration of the low amplitude signal (< 40 μV) at the end of QRS (LAS40) and the left ventricular myocardial mass index (r = 0.76, p < 0.01), as well as between LAS40 and RMS40 with the end diastolic diameter of the left ventricle adjusted to the body surface area (r = 0.76, p < 0.01 and r = -0.83, p < 0.01, respectively). The patients with a pseudo normal type of diastolic dysfunction (n = 27) showed an association between their NT-proBNP levels and TotORSF (r = 0.56, p < 0.01).

Conclusion: The prevalence of late ventricular potentials among patients with early stage chronic heart failure and preserved left ventricular ejection fraction is not high. The parameters of electrophysiological myocardial instability in patients with concentric hypertrophy are mostly influenced by the size of heart chambers, whereas in those with the eccentric one, by the myocardial mass and volume parameters. The risk of sudden cardiac death is higher in patients with a pseudo normal type of diastolic dysfunction.

Pulmonary artery agenesis combined with tetralogy of Fallot is the most rarely seen congenital heart disease. Children with this anomaly are an especially problematic category of patients undergoing staged surgical repair. The postoperative period quite often is complicated with shunt thrombosis while a redo open surgery is associated with a very high risk; therefore, endovascular repair is a preferred procedure. We describe a case of right ventricular outflow tract stenting in a 8 month old girl with tetralogy of Fallot and right pulmonary artery agenesis. The patient was admitted at 3 month after performing of a left-sided modified Blalock-Taussig shunt with severe signs of heart failure and desaturation caused by shunt thrombosis. Assessments performed at 2 months after stenting of the outflow tract demonstrated good oxygen saturation in arterial blood (80% and above) and improvement of heart failure symptoms to NYHA II class.

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