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Background: Transcatheter aortic valve replacement (TAVR) has proven to be a valuable alternative to conventional surgical aortic valve replacement in high risk and surgically in operable patients who suffer from severe symptomatic aortic stenosis. However, a significant number of complications, associated with both the learning curve and device specificity, have required attention and subsequent improvement. The Symetis transapical TAVR system is a self-positioning bioprosthesis composed of a non-coronary leaflet of surgical quality porcine tissue valve sewn into a self-expanding nitinol stent that iscovered with a PET-skirt. Methods: From June to September 2013 six patients have been operated on severe aortic stenosis using the new TAVR device. All patients have undergone critical assessment of a local Heart Team and have been disqualified from conventional AVR. Five were woman. Mean age was 82.3 ± 2.0 (mean LogEuroScore 23.9 ± 14.3). Four patients suffered from coronary artery disease — two had history of previous percutaneous coronary intervention with intracoronary stents, while the next two had history of coronary artery bypass grafting. Diabetes was frequent (n = 3) as well as chronic obstructive pulmonary disease (n = 4). Carotid artery disease was encountered in three patients similarly to atrial fibrillation. Mean left ventricular ejection fraction (LVEF) was 51.5 ± 11.8%, but one patient had suffered from low-flow-low-gradient aortic stenosis with LVEF of 29%. Results: The procedure was carried out successfully in all six cases. Two patients have received the valve sized L, three — M and one — S. Mean procedure time was 180 ± 19 min, mean cine 7.2 ± 1.2 min. Mean X-ray dose 930 ± 439 mGy, while mean volume of contrast given was 135 ± 61 mL. In all patients but one perivalvular leak (PVL) was not present. One patient had trace of PVL. Also, good LVEF was noted in all patients. Similar findings were obtained 30 days post procedure. No strokes, transient ischaemic attack or other cerebrovascular incidents were observed. Conclusions: This brief clinical communication reports the first Polish experience with the second generation of TAVR device — the Symetis Acurate Transapical Aortic Valve. While it lacks large patient population and longer follow-up, it reveals that TAVR procedure can be performed safely, with minimal X-ray exposure time and contrast given and successfully — with almost nonexistent PVL and no cerebrovascular incidents or heart rhythm disturbances. Heart Team approach is vital, and transapical access should not be treated inferiorly, but rather as an equally appealing TAVR option.

The frozen elephant trunk (FET) technique is a modification of the traditional elephant trunk method, which was introduced by Borst in 1983 in order to treat extensive thoracic aortic aneurysms. The crux of the new method is the different type of aortic prosthesis, consisting of a Dacron part (with or without branches leading to the arterial vessels which exit the aortic arch) and a port for extracorporeal circulation with a self-expanding nitinol stentgraft. This combination enables a complete one-stage treatment of the pathologies within the arch and the proximal segment of the descending aorta; moreover, it facilitates the performance of a two-stage hybrid treatment of extensive thoracic aortic aneurysms involving a significant part of the descending aorta. This article presents the cases of four patients with extensive aortic disease, who were implanted with Thoraflex prostheses (Vascutek, Scotland).

Frozen elephant trunk technique represents a valuable therapeutic option for patients with extensive pathology of thoracic aorta. Thoraflex™ hybrid prosthesis (Vascutek, Terumo, Inchinnan, UK) is one of the commercially available devices in which a stent graft is combined with branched vascular tube mimicking the aortic arch anatomy. Owing to the sewing collar between the stented and unstented portions, this hybrid prosthesis offers a valuable addition to the surgical armamentarium for patients with huge thoracic aorta aneurysms, in whom the aortic diameter exceeds the diameter of available stent grafts. However, the standard factory form of the quadrifurcated arch prosthesis does not always fit to the patient's anatomy and demands a deviation from the anatomical anastomosing of the branches with the respective supra-aortic arteries. A technique of non-anatomical implantation of supra-aortic arteries for customizing the standard form of the Thoraflex prosthesis is described, which facilitates the surgery without limiting the functionality of this hybrid prosthesis.

We describe the case of a 54-year-old patient after renal and heart transplantation in whom uncontrolled hypertension was diagnosed. Despite combined antihypertensive therapy, no significant therapeutic effect was achieved. Clinical assessment of ambulatory blood pressure monitoring (ABPM) revealed the ineffectiveness of a bisoprolol, nitrendypin, klonidyn, ramipryl, furosemide, and doxasosine combination used at high doses. High blood pressure levels with their effect on a hypertrophic transplanted heart (left ventricular mass 254 g) and poor renal graft function (39 mL/kg/min) posed an extremely high risk of future cardiovascular complications, and were the reason to perform a native renal arteries denervation. The procedure was carried out through the right femoral artery with the use of a 6F guiding catheter. During a 1-year observation, significant decreases in ABPM systolic and diastolic blood pressures were observed after the procedure (168/88 mm Hg vs 154/77 mm Hg, respectively). Moreover a significant regression of left ventricular mass (215 g/m2) and stable renal graft function were noted. The presented case shows that native renal arteries denervation may be successful and safe in kidney and heart transplant recipients. Moreover, during the 1-year follow-up, the reduction in blood pressure was followed by a reduction in transplanted heart hypertrophy, both leading to regression of cardiovascular risk for the patient.

The evaluation of prognosis and determination of a long-term treatment strategy is an important element of management in patients with heart failure (HF).The aim of the study was to determine the prognostic value of the Model for End-Stage Liver Disease (MELD) and its modifications, MELD and serum sodium (MELD-Na) and MELD excluding the international normalized ratio (MELD-XI), as well as other independent risk factors for death during a 4-year follow-up. We analyzed retrospectively 143 patients with advanced HF, evaluated for heart transplant between 2009 and 2011. Patients using warfarin were excluded from the study. The long-term follow-up data were obtained during follow-up visits and/or phone contact with the patients or their families.The age of the patients was 54 (48-59) years and 88.1% of patients were male. Mortality rate during the follow-up period was 49%. The MELD scores (hazard ratio [HR], 1.12; P .001), as well as serum high-sensitivity C-reactive protein (hs-CRP; HR, 1.01; P .01) and N-terminal pro-brain natriuretic peptide (NT-proBNP; HR, 1.01; P .05) levels, were independent risk factors for death. Receiver operator characteristic analysis indicated that a MELD cutoff of 10 (area under the curve [AUC], 0.756; P .0001], MELD-XI cutoff of 13.0 (AUC, 0.720; P .0001), MELD-Na cutoff of 13.0 (AUC, 0.813; P .0001), hs-CRP cutoff of 4.02 (AUC, 0.686; P .001), and NT-proBNP cutoff of 1055 (AUC, 0.722; P .001) were the best predictive values as predictors of death.MELD, MELD-Na, and MELD-XI scores are prognostic factors for death during a 4-year follow-up. A high MELD score is an independent prognostic factor for death. NT-proBNP and hs-CRP serum concentrations are other independent factors influencing death.

Background: Coronary artery bypass graft (CABG) surgery is rarely performed in very young patients. The purpose of our study is to compare the characteristics, treatments, in-hospital, and long-term outcomes of two groups of patients less than 40 years of age who had CABG in two successive decades: 1990-2000 and 2001-2011. Methods: We identified 145 consecutive patients who underwent primary isolated CABG. Group 1 consisted of 78 patients operated between 1990-2000 and group 2 consisted of 67 patients operated between 2001-2011. Composite end point assessed at follow-up period involved death or recurrence of symptoms, which we defined as myocardial infarction, a need for percutaneous coronary intervention (PCI), reoperation, or congestive heart failure (CHF). Results: Smoking and hypercholesterolemia before CABG were noted as more frequent in group 1 than in group 2: 96.1% versus 83.6%, P = .011; 88.5% versus 61.2%, P = .0001, respectively. Patients from group 2 more frequently received one graft (29.8% versus 11.5%, P = .0059), were operated with off-pump (41.8% versus 0%, P < .0001) or MIDCAB (28.4% versus 0%, P = .0008) techniques, and had complete arterial revascularization (58.2% versus 23.1%, P < .0001). Group 1 patients had a higher prevalence of composite end point (33.9% versus 17.9%, P = .035), with no significant difference in mortality (11.5% versus 10.4%, P = .83).Conclusion: Patients operated between 1990-2000 had a higher prevalence of smoking and hypercholesterolemia and higher frequency of composite-end point during folow-up period without significant difference in mortality.

The Model for End-Stage Liver Disease (MELD) scoring system incorporating a combination of hepatic and renal laboratory parameters does not adequately reflect the degree of multi-organ dysfunction in patients with heart failure, who need oral anticoagulation. In order to exclude the impact of oral anticoagulation on the international normalized ratio (INR), we used the MELD excluding INR (MELD-XI) score. The aims of the study were to calculate the individual preoperative MELD-XI score and its ability to predict 1-year mortality after heart transplantation and to identify other preoperative laboratory prognostic parameters.We retrospectively analysed data of 87 consecutive adults undergoing heart transplantation between 2011 and 2014. Clinical data and laboratory parameters for the calculation of the MELD-XI score were obtained at the time of admission for the heart transplantation.The average age of the patients was 48.8 ± 13.3 years and 68.9% of them were male. During the observation period, the mortality rate was 18.4%. Multivariate analysis of Cox proportional hazard confirmed that the pretransplantation MELD-XI score (hazard ratio [HR] = 1.625 [1.286-2.053]; P .001), sodium serum concentration (HR = 0.824 [0.677-1.001]; P .05) and highly sensitive C-reactive protein (hs-CRP) serum concentration (HR = 1.045 [1.008-1.083]; P .02) were independent predictors of death during the first year after heart transplantation. Area under the receiver operating characteristic (ROC) curve (AUC) indicated a good discriminatory power of MELD-XI (AUC 0.997; P .04) and plasma sodium concentration (AUC 0.901; P .01) in death prediction.Our study confirms that the pretransplantation MELD-XI score, as well as serum sodium and hsCRP concentrations, may be used to estimate postoperative risk in heart transplant recipients during a 1-year follow-up.

Cardiac allograft vasculopathy (CAV) still remains to be one of the most important limiting factors for heart transplant recipients' long-term survival. The aim of our study was to identify the perioperative risk factors impacting the occurrence of CAV during the long-term follow-up.We retrospectively analysed the data from 198 consecutive adult patients, who underwent heart transplantation between 2007 and 2012, in whom at least one routine coronarography (CAG) was performed. CAV onset was defined as any lesion seen at least at one routine CAG.The average follow-up was 63.6 ± 14.7 months. The frequency of CAV in the analysed population was 36 (18.1%). Multivariate stepwise logistic regression analysis confirmed that NT-proBNP plasma concentration directly before heart transplant [logNT-proBNP OR = 16.455 (4.587-31.036), P .0001], fibrinogen plasma concentration a month after heart transplant [OR = 1.022 (1.009-1.035), P .001] and occurrence of diabetes [OR = 12.355 (1.417-35.750), P .001], were independent predictors of CAV. Area under the ROC curves (AUC) indicated a well discriminatory power of plasma fibrinogen [AUC 0.9278, P .001] and plasma NTproBNP concentration [AUC 0.9514, P .001] in CAV prediction. The optimal cut-off value of fibrinogen was 509 mg/dL, and of NT-proBNP was 10080 pg/mL.Our data show that NT-proBNP and fibrinogen plasma concentrations as well as occurence of diabetes, both preexisting and new onset after heart transplant can be used to identify patients at risk of developing CAV.

Over the last twenty years, minimally invasive aortic valve replacement (MIAVR) has evolved into a safe, well-tolerated and efficient surgical treatment option for aortic valve disease. It has been shown to reduce postoperative morbidity, providing faster recovery and rehabilitation, shorter hospital stay and better cosmetic results compared with conventional surgery. A variety of minimally invasive accesses have been developed and utilized to date. This concise review demonstrates and discusses surgical techniques used in contemporary approaches to MIAVR and presents the most important results of MIAVR procedures.Przez ostatnie 20 lat małoinwazyjna wymiana zastawki aortalnej (MIAVR) stała się bezpieczną, dobrze tolerowaną i skuteczną opcją leczenia chorób zastawki aortalnej. W porównaniu z tradycyjną sternotomią wykazano, że małoinwazyjna chirurgia zastawki aortalnej zmniejsza liczbę powikłań pooperacyjnych, zapewniając szybszą rehabilitację i powrót do zdrowia, krótszą hospitalizację jak również lepsze efekty kosmetyczne. Do chwili obecnej powstało wiele technik operacyjnych z małego dostępu. Poniższy artykuł przedstawia metody operacyjne oraz najbardziej istotne wyniki współczesnej małoinwazyjnej wymiany zastawki aortalnej.

Objective: Postinfarction ventricular septal defect (PIVSD) is a rare and life-threatening complication with high risk of both surgical and medical treatment. Another option available now is transcatheter closure. The purpose of this paper is to report the results of such treatment with Amplatzer occluders. Method: Seven patients aged from 51 to 71 years were included. The procedure was performed between 2 and 10 weeks after myocardial infarction. One patient had double residual VSD (2 months after previous surgery) and another, coexisting critical stenosis of right coronary artery (RCA). All patients were in III/IV NYHA class, on intropes, one patient on aortic balloon counterpulsation. Venous jugular approach was used to close the VSD in six patients, venous transfemoral in one patient. Implantation of six Ampaltzer atrial septal occluders (ASO) and one muscular Amplatzer VSD occluder (VSO) were performed. Results: All procedures but two were finished successfully. In one patient, the defect could not be entered neither from the venous nor the arterial side due to unusual oblique course (which was confirmed during subsequent operation). In the second patient (2 weeks after MI), the reason was unstable position of 24 mm ASO (probably due to necrotic borders of VSD). Immediate significant clinical improvement was achieved in all patients, in whom PIVSD was closed with Amplatzer occluders. In one postsurgical patient, two ASO were used; in another patient, prior to VSD closure, PTCA and stent implantation to RCA was performed. The stretched diameter of PIVSD ranged from 8 to 22 mm, the size of implanted Amplatzer occluders from 12 to 24 mm. Fluoroscopy time was 60 min (18-120). During the procedure, ventricular fibrillation requiring defibrillation was observed in three patients. One patient died 1 week after the procedure because of multiorgan failure and increasing mitral incompetence (MI). Conclusions: Despite some technical problems, implantation of Amplatzer occluders, is an attractive option of treatment of patients with subacute PIVSD.

Aims The aim of the present study was to isolate mesenchymal stromal cells (MSC) with CD105+CD34- phenotype from human hearts, and to investigate their therapeutic potential in a mouse model of hindlimb ischemia and myocardial infarction (MI). The study aimed also to investigate the feasibility of xenogeneic MSCs implantation. Methods and Results MSC isolated from human hearts were multipotent cells. Separation of MSC with CD105+CD34- phenotype limited the heterogeneity of the originally isolated cell population. MSC secreted a number of anti-inflammatory and proangiogenic cytokines (mainly IL-6, IL-8, and GRO). Human MSC were transplanted into C57Bl/6NCrl mice. Using the mouse model of hindlimb ischemia it was shown that human MSC treated mice demonstrated a higher capillary density 14 days after injury. It was also presented that MSC administrated into the ischemic muscle facilitated fast wound healing (functional recovery by ischemic limb). MSC transplanted into an infarcted myocardium reduced the post-infarction scar, fibrosis, and increased the number of blood vessels both in the border area, and within the post-infarction scar. The improvement of left ventricular ejection fraction was also observed. Conclusion In two murine models (hindlimb ischemia and MI) we did not observe the xenotransplant rejection. Indeed, we have shown that human cardiac mesenchymal stromal cells with CD105+CD34- phenotype exhibit therapeutic potential. It seems that M2 macrophages are essential for healing and repair of the post-infarcted heart.

The concept of a hybrid approach, combining the most effective techniques of surgical and endocardial catheter ablation has resulted in the creation of the convergent ablation procedure. This novel, pericardioscopic, hybrid approach can be an effective option for highly symptomatic patients with persistent atrial fibrillation (PSAF) and longstanding persistent atrial fibrillation (LSPAF) for whom standalone surgical or endocardial ablation procedures offer sometimes unsatisfactory outcomes.To assess the safety, efficacy and effectiveness of a hybrid epicardial and endocardial radiofrequency ablation for the treatment of PSAF and LSPAF.Single-centre, prospective, non-randomised clinical study. Between August 2009 and December 2011, 27 patients with PSAF (n = 5) and LSPAF (n = 22) underwent hybrid ablation (HABL). Mean age was 52.52 ± 11.27 years, and the mean EHRA class was 2.5; 14 (51.8%) patients had a history of electrical cardioversion (n = 6) or catheter ablation (n = 8). Five patients had left ventricular ejection fraction (LVEF) of less than 35%. Mean AF duration for all patients was 3.46 ± 2.5 years. All patients were on antiarrhythmic drugs (AAD) and oral anticoagulation. Patients were scheduled for three, six and 12 month follow-up with seven day Holters, REVEAL® XT and ECHO measurements.The HABL procedure was feasible in all patients. At six months post procedure, 72.2% (13/18) of patients were in SR, and 66.5% (12/18) were off class I/III AADs. Four patients were in AF and one patient developed right atrial flutter. At one year post procedure, 80% (8/10) of patients were in SR and off class I/III AADs. At two year post procedure, 100% (6/6) of patients were in SR and off class I/III AADs. Rapid change in left ventricular function was noted in patients with low LVEF (≤ 35%) prior to the procedure. Patients with LVEF +40% had less apparent improvement.Hybrid, epicardial and endocardial, radiofrequency ablation is feasible and safe, effectively restoring sinus rhythm in the vast majority of patients with PSAF and LSPAF.

The concept of hybrid room is to combine capabilities of cardiosurgery operating room and fully equipped cathlab. Since May 2011, an ultramodern hybrid room has been working, in our center. The cases reported in this article show the possibilities of cooperation of cardiosurgeons, anaesthesiologists and invasive cardiologists in performing difficult, complex cardiovascular interventions. In near future the capabilities of hybrid room will allow to perform simultaneously a number of complex cardiovascular procedures. It should not only shorten the time of hospitalisation but also substantially improve the patients comfort.

Hybrid coronary artery revascularisation (HCR) is a combination of minimally invasive left internal mammary artery bypass grafting to the left anterior descending artery (LAD) and percutaneous coronary interventions (PCI) with drug eluting stent implantation to other coronary arteries. Due to the paucity of data from large, prospective randomised trials comparing HCR to standard surgical revascularisation, the POLMIDES study has been designed to assess the safety and efficacy of HCR in patients with multivessel coronary artery disease (CAD) referred for standard coronary artery bypass grafting (CABG).The primary objective is evaluating the feasibility and safety of HCR.Feasibility has been defined by means of the percentage of patients with a complete hybrid procedure according to the study protocol and a percentage of conversion to standard CABG. Safety has been defined as the occurrence of major adverse cardiac events such as death, myocardial infarction, stroke, repeat revascularisation and major bleeding within the 12 month period after randomisation. All consecutive patients with angiographically confirmed multivessel CAD involving LAD and a critical (70%) lesion in at least one major epicardial vessel (except LAD) amenable to both PCI and CABG referred for conventional surgical revascularisation, will be randomised in a 1:1 fashion for HCR or standard surgical revascularisation.The POLMIDES is a prospective, randomised pilot trial designed to determine whether HCR in patients with multivessel CAD referred for conventional CABG is safe, feasible and efficacious (ClinicalTrials.gov number, NCT01035567). Kardiol Pol 2011; 69, 5: 460-466.

According to current guidelines surgical revascularisation is a gold standard of treatment in patients with multivessel and left main coronary disease. Hybrid revascularisation, in two stages: first - minimally invasive direct coronary artery bypass grafting procedure with left internal mammary artery conduit to left anterior descending artery and second stage - percutaneus coronary intervention with drug eluting stent in non-left anterior descending vessels may be safe and effective alternative in patients with multivessel and left main coronary disease.

We report a case of a 70-year-old woman admitted with symptoms of decompensated heart failure. Magnetic resonance imaging revealed lipomatous hypertrophy of the interatrial septum with partial upper right atrial inflow obstruction, partial obstruction of the right ventricular outflow tract, and excessive accumulation of adipose tissue in the pericardial space. The patient underwent excision of the septal lipomatous mass, which relieved the right ventricular outflow obstruction.

Objectives Extracorporeal circulation is associated with the systemic inflammatory response syndrome. The objective of this study was to measure plasma and myocardial matrix metalloproteinase 2 and 9 levels in patients undergoing off-pump coronary artery bypass and coronary artery bypass grafting. Methods Twenty patients subjected to coronary artery bypass grafting and 20 subjected to off-pump coronary artery bypass surgery were included in this study. In both procedures blood was collected in 7 equivalent time points up to 12 hours after grafting. The myocardial biopsy specimens were collected before and after extracorporeal circulation in the coronary artery bypass grafting group and after harvesting and completion of proximal anastomoses in the off-pump coronary artery bypass group. Matrix metalloproteinase levels were measured by means of zymography. Myeloperoxidase and tissue inhibitor of metalloproteinase 1 and 2 levels were measured with an enzyme-linked immunosorbent assay. Results Coronary artery bypass grafting but not off-pump coronary artery bypass led to a 700- to 900-fold increase of plasma matrix metalloproteinase 9 levels. A small but significant increase in matrix metalloproteinase 2 levels was detected in both procedures. Myocardial matrix metalloproteinase 9 levels significantly increased at the end of coronary artery bypass grafting and off-pump coronary artery bypass. Increased matrix metalloproteinase 9 activity at the end of extracorporeal circulation was accompanied by augmentation of the endogenous matrix metalloproteinase inhibitors tissue inhibitor of metalloproteinase 1 and 2 in plasma, but its magnitude was unable to balance the plasma matrix metalloproteinase 9 increase. The matrix metalloproteinase 9 content in plasma at the end of extracorporeal circulation correlated with the myeloperoxidase plasma concentration ( r 2 = 0.8212, P Conclusion We propose that release of matrix metalloproteinase 9 might contribute to the extracorporeal circulation–induced inflammatory reactions.

Vascular endothelial growth factor (VEGF-A) is one of the most important proangiogenic factors. It has many isoforms encoded by one gene. The occurrence of these isoforms is associated with the process of alternative splicing of mRNA. Some of the splice forms are perceived as tissue specific. The aim of this study was to determine the alternative splicing of VEGF-A mRNA in dilated cardiomyopathy, especially at the level of particular myocardial layers. The assessment of post-transcriptional modifications of VEGF-A mRNA was made on specimens taken from the explanted hearts of patients undergoing cardiac transplantation. Molecular and histopathological studies were perfomed on particular layers of the myocardial muscle (endocardium, myocardium, epicardium). A molecular analysis of cardiac samples was performed by quantitative analysis of the mRNA of the studied VEGF-A isoforms (VEGF121, -145, -165, -183, -189, and -206) using QRTPCR with an ABI-PRISM 7700-TaqMan sequence detector. 72 cardiac specimens taken from the explanted hearts were analyzed. Each of the studied VEGF-A splice forms was present in the evaluated hearts, but the types of alternative splicing of mRNA were different in particular layers. Quantitative analysis revealed different amounts of the studied isoforms. Generally, significantly increased expression of the VEGF-A isoforms was observed in samples taken from hearts with post-inflammatory etiology of cardiomyopathy. Our conclusions are: 1. All the studied VEGF-A isoforms were found in the human hearts, including those thusfar considered characteristic for other tissues. 2. Significant differences were observed in the expression of the VEGF-A splice forms with respect to the myocardial layers and the location of the cardiac biopsy. 3. Repetitive and comparable results for samples with post-inflammatory etiology were obtained, and they revealed considerably higher amounts of VEGF-A isoforms compared to specimens with idiopathic etiology.

Purpose Treatment using of short-term pulsatile mechanical circulatory support (MSC) is often realized in units that are common for all patients undergoing cardiac surgery (CS), including orthotopic heart transplantation (OHT). Aim of the study was to compare the etiology of surgical wound infection among patients receiving MCS treatment, OHT, or standard CS procedure. Methods and Materials A retrospective analysis of wound infections was performed in 8998 patients undergoing CS in years 2007-2012: 5 patients treated with MCS (23M/2F, 41.2±15y/o, 21LVAD/4BIVAD), 195 OHT recipients (128M/67F, 44.4±17y/o), and 8778 patients undergoing remaining CS procedures (6116M/2662F, 62.0±12y/o). A comparison of wound infection frequency as well as specific pathogens occurrence among MSC, OHT and CS patients was performed for the whole period of observation and for each year separately. Results Superficial wound infections were found in 6(24%) MCS patients, 8(4.1%) OHT recipients, and 97(1.1%) CS patients (p Conclusions Despite localization in the same hospital unit MCS and other CS patients don’t share the same etiology of wound infections. Gram-negative flora is predominant in MCS patients, while typical Gram-positive skin flora is more frequent source of infection in OHT and CS patients.

According to literature data, self-renewing, multipotent, and clonogenic cardiac c-Kit(+) progenitor cells occur within human myocardium. The aim of this study was to isolate and characterize c-Kit(+) progenitor cells from explanted human hearts. Experimental material was obtained from 19 adult and 7 pediatric patients. Successful isolation and culture was achieved for 95 samples (84.1%) derived from five different regions of the heart: right and left ventricles, atrium, intraventricular septum, and apex. The average percentage of c-Kit(+) cells, as assessed by FACS, ranged between 0.7 and 0.9%. In contrast to published data we do not observed statistically significant differences in the number of c-Kit(+) cells between disease-specific groups, parts of the heart or sexes. Nevertheless, c-Kit(+) cells were present in significant numbers (11-24%) in samples derived from three explanted pediatric hearts. c-Kit(+) cells were also positive for CD105 and a majority of them was positive for CD31 and CD34 (83.7 ± 8.6 and 75.7 ± 11.4%, respectively). Immunohistochemical analysis of the heart tissue revealed that most cells possessing the c-Kit antigen were also positive for tryptase, a specific mast cell marker. However, flow cytometry analysis has shown cultured c-Kit(+) cells to be negative for hematopoietic marker CD45 and mast cell marker CD33. Isolated c-Kit(+) cells display mesenchymal stem cell features and are thought to differentiate into endothelial cells.