[Changes in Pulmonary Hemodynamics Resulted From Long-Term Mechanical Heart Support].

Aim      To study the dynamics of right ventricular function and pulmonary hemodynamics in patients with pulmonary hypertension during mechanical circulatory support of the heart.Material and methods  A retrospective analysis was performed for 25 implantations of left ventricular assist device performed in the Meshalkin National Medical Research Center from 2006 through 2021. Mechanical assist devices were implanted in 21 men and 4 women (median age, 37.5 [29; 48] years). All patients had severe, NYHA functional class III-IV chronic heart failure refractory to the optimal drug therapy. Invasive measurements showed that mean pulmonary arterial pressure (MPAP) was 50 [44.5; 60] mm Hg, transpulmonary pressure gradient (TPG) was 16 [14; 19] mm Hg, and calculated pulmonary vascular resistance was 5.4 [4.9; 9] Wood units, which is an absolute contraindication (TPG >15 mm Hg or pulmonary vascular resistance >5 Wood units) for heart transplantation (HT).Results Duration of left ventricular support was from 17 to 948 days. For 12 (48 %) patients, the HT was performed at 180-948 days following the implantation of left ventricular assist device; 3 patients are presently waiting for HT; 10 patients died from various complications, 6 of them died during the hospital stage. Already during the early stage after the implantation of the mechanical assist device, pulmonary hemodynamics significantly improved. Thus, in one week, MPAP decreased from 50 [44.5; 60] mm Hg to 36 [33; 38] mm Hg (р=0.012) whereas pulmonary vascular resistance decreased from 5.4 [4.9; 9] to 2.9 [2.4; 3.6] Wood units (р=0.008). Follow-up showed further improvement of pulmonary hemodynamics; at 1 month, MPAP was 29 [27; 30] mm Hg and by the time of HT, MPAP was 2.0 [24.8; 26.3] mm Hg (р=0.01), i.e., reached a normal level, which made it possible to perform HT. Similar dynamics was observed for other variables that reflected pulmonary hemodynamics.Conclusion      Mechanical support of the heart is able to alleviate manifestations of pulmonary hypertension in most patients with end-stage heart failure. It is necessary to develop an algorithm for identifying the category of patients with a high risk of progression of right ventricular failure.

Stimulation of angiogenesis in rat ischemic limb by intramuscular implantation of mononuclear fraction cells from autologous bone marrow.

We studied angiogenic effects of two variants of indirect revascularization (transplantation of mononuclear fraction cells from autologous bone marrow alone or in combination with laser tunneling) after modeled ischemia of the lower limbs in rats. Doppler sonography and immunofluorescence studies showed that intramuscular implantation of isolated fraction of autologous bone marrow mononuclear cells in combination with laser tunneling of the muscles is most effective and can be recommended as a method of angiogenesis stimulation in non-reconstructable distal vascular pathology of the extremities.

Angiomatosis and ectopic ossification in the dog myocardium after intramyocardial implantation of autologous bone marrow mononuclears in experimental coronary disease.

Disseminated ossification of the myocardium and severe angiomatosis were detected in sites of implantation of unseparated bone marrow mononuclear fraction cells in dogs with experimental chronic coronary disease. Minor immunocytochemical differences in cells of the mononuclear fraction adhering and not adhering to plastic were found. Significant differences in the expression of mRNA of chondro-osteogenesis genes (aggrecan, lumican, and osteopontin) in adherent and nonadherent cells were detected. The expression of aggrecan gene mRNA was 3-fold lower, of lumican gene 6-fold, and of osteopontin gene 11-fold lower in nonadherent cells compared to adherent fraction.

Cardiomyocyte regeneration in pericicatricial zone of the myocardium after laser tunneling and implantation of bone marrow mononuclear cells.

Using canine model of chronic postinfarction myocardial ischemia we evaluated angiogenesis and cardiomyogenesis after combined revascularization by laser tunneling of the pericicatricial zone followed by implantation of bone marrow mononuclear cells into the channels. It was shown that the numerical density of arterioles and capillaries considerably increased 1 month after revascularization. We also observed a considerable increase in the density of cardiomyocyte nuclei in the test area, a 2-fold increase in the total area of nuclei, and an increase in the mean area of cardiomyocyte nuclei. The number of PNCA-positive cardiomyocytes significantly increased after combined revascularization. Our findings suggest that combined revascularization of the pericicatricial zone of the myocardium promoted angiogenesis and stimulates regeneration of cardiomyocytes.

Ultrastructural analysis of secretory granules of myocardial capillary endothelium in cardiosurgical stress.

In patients with chronic myocardial tissue hypoxia irrespective of the disease (Fallot's tetralogy, coronary disease) factors of cardiosurgical stress initiate a drop of secretory production in coronary capillary endothelium and obstruction of the intravascular space by blood cells. In children the peak of exocytosis of secretory granules coincides with the period of aortic occlusion, while in adults it is attained at the stage of reperfusion.