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Maciej Kolowca

Publications and source records attributed to Maciej Kolowca.

10 recordsLinked to original sources
PubMed2006

Plasma ANP and renin-angiotensin-aldosterone system as new parameters describing the hemodynamics of the circulatory system after implantation of stented or stentless aortic valves.

BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement (AVR) in patients with a small aortic root involves the occurrence of patient-prosthesis mismatch (PPM). Recent reports have shown that a reduced effective orifice area index (EOAI) may not be the sole factor responsible for this complication. The study aim was to analyze the activity of atrial natriuretic peptide (ANP)/renin-angiotensin-aldosterone (RAA) after implantation of stented or stentless valves. METHODS: Between 2001 and 2003, a total of 30 patients operated on at the authors' institution received either a stentless Freestyle bioprosthesis (group A; n = 15) or a stented Mosaic bioprosthesis (group B; n = 15). The demographics of both groups were similar, and all patients underwent echocardiography preoperatively, and at one, six and 12 months postoperatively. The activity of the RAA system and plasma ANP level were measured in all patients preoperatively and at one and six months postoperatively. RESULTS: At one month after AVR, statistically significant inter-group differences were noted in plasma renin activity (group A, 3.7 +/- 2.1 ng/ml/h; group B, 5.6 +/- 0.8 ng/ml/h; p <0.05; control value 0.3-5.3 ng/ml/h). For ANP, statistically significant differences were present at one month after surgery (group A, 36.3 +/- 5.1 pg/ml; group B, 62.9 +/- 9.2 pg/ml; p <0.005; control value 27.3-37.2 pg/ml). On echocardiography, the ejection fraction, aortic valve gradient, EOAI and left ventricular mass index (LVMI) were assessed. A statistically significant difference was identified for the LVMI at 12 months postoperatively (group A, 216 +/- 13 g/m2; group B, 240 +/- 18 g/m2; p <0.05). In terms of other parameters both groups were similar. CONCLUSION: The implantation of an aortic valve prosthesis affects the hemodynamics of the entire circulatory system, and thus the activity of natriuretic systems. Whilst stentless valves allowed much more rapid normalization of circulatory system hemodynamics (one month), no difference compared to preoperative was identified after six months. Natriuretic peptides appear to provide more sensitive (long-term) but less specific (short-term) assessment of circulatory system behavior than echocardiography.

Aged↗
PubMed2005

Angiotensin-converting enzyme inhibitors reveal non-NO-, non-prostacycline-mediated endothelium-dependent relaxation in internal thoracic artery of hypertensive patients.

BACKGROUND: We have shown that treatment of hypertension with ACE inhibitors (ACE-I) enhances relaxation to acetylcholine in human internal thoracic artery (ITA) above this in nonhypertensive patients receiving no ACE-I. Present study assesses the endothelium-dependent responses mediated by neither NO nor prostacyclin in human ITA. METHODS: We compared isolated ITA rings from hypertensive patients treated with ACE-I (ACE-I group) with those from normotensive patients on no ACE-I (control group). Relaxation to acetylcholine was assessed before and after inhibition of NO synthase and cyclooxygenase with L-NMMA and indomethacin, respectively. RESULTS: The maximal relaxation in ACE-I group was 79+/-3.3% and was depressed by incubation with L-NMMA and indomethacin to 41+/-2.7% (p<0.001); pD(2)=7.7+/-0.1 vs. 7.4+/-0.8 (p=0.265). The maximal relaxation to acetylcholine was lower in the control group: 65+/-3.3% (p=0.01); pD(2)=7.5+/-0.1 (p=0.07). Incubation with L-NMMA and indomethacin produced contraction to acetylcholine with a maximum of 43+/-7% (p<0.001); pD(2)=5.3+/-0.3 (p<0.001). The area under the concentration-response curve for acetylcholine-induced relaxation in ACE-I group equaled [arbitrary units] 596+/-71 and after incubation with L-NMMA and indomethacin 281+/-40 (p=0.002). Estimated LNMMA- and indomethacin-resistant relaxation, absent in control group, accounted for 47+/-4% of relaxation to acetylcholine in ACE-I group. Estimated NO- and prostacyclin-mediated relaxation was higher in control group than ACE-I group: 628+/-74 vs. 315+/-47 (p=0.009). CONCLUSIONS: The results suggest that therapy with ACE-I improves endothelial function of hypertensive patients mainly by enhancing the endothelium-derived hyperpolarizing factor (EDHF) (and not NO)-mediated responses. It seems that it reveals measurable non-NO- non-PGI-mediated endothelium-dependent relaxation otherwise absent in conduit arteries.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2005

Skeletonization of internal thoracic artery affects its innervation and reactivity.

OBJECTIVE: The studies showing the superior characteristics of ITA graft and its impact on the clinical results of coronary artery surgery were performed with ITA harvested almost exclusively as a pedicle. This study assesses the impact of ITA skeletonization on its innervation and reactivity. METHODS: Segments of skeletonized and non-skeletonized ITA were stained with antibodies against protein S-100 to look for the presence of sympathetic nerve fibers. The functional studies were performed on segments of discarded human pedicled ITA that were divided into two 3mm rings, one skeletonized and another non-skeletonized. We compared concentration-effect relationships for the contraction to norepinephrine and endothelium-dependent relaxation to acetylcholine and bradykinin, as well as endothelium-independent relaxation to sodium nitroprusside in skeletonized and non-skeletonized segments of the same ITA. RESULTS: Skeletonized ITA was devoid of protein S-100 positive nerve fibers. It contracted stronger (maximal response 37.0+/-2.04 vs. 25.4+/-1.83mN (P<0.001)) and was twice as sensitive to norepinephrine: pD(2) 6.03+/-0.10 vs. 5.70+/-0.12 (P=0.035). The endothelium-dependent relaxation responses did not differ between skeletonized and non-skeletonized ITA rings. The skeletonized ITA rings appeared over 10 times more sensitive to sodium nitroprusside: pD(2) 6.66+/-0.20 vs. 5.59+/-0.37 (P=0.012)-potency ratio 11.61. The maximal responses did not differ significantly: 112.0+/-6.71 vs. 129.4+/-16.4% (P=0.33). CONCLUSIONS: Skeletonization results in sympathectomy of ITA. It has no effect on endothelium-dependent relaxation but increases reactivity of ITA to norepinephrine. This augmented response to alpha-agonist is small, in comparison with over a ten-fold increase in sensitivity to sodium nitroprusside. Pedicled and skeletonized ITA are functionally significantly different vessels when studied in vitro.

Acetylcholine↗
PubMed2004

Diazoxide provides protection to human myocardium in vitro that is concentration dependent.

BACKGROUND: Diazoxide has been shown to confer significant myocardial protection in many experiments. This study was designed to assess its influence on the structural injury and functional recovery of human myocardium subjected to hypoxia/reoxygenation in vitro. METHODS: The isolated electrically driven human right atrial trabeculae, obtained during cardiac surgery, were studied. The tissue bath was oxygenated with 95% oxygen and 5% carbon dioxide, hypoxia being obtained by replacing oxygen with argon. The influence of diazoxide on atrial contractility was studied first. Next, the two trabeculae from one atrial appendage were studied simultaneously, adding diazoxide to the tissue bath 10 minutes before hypoxia in one, with another serving as a control. We tested 10(-4.5) mol/L and 10(-4) mol/L diazoxide in three sets of experiments testing 30, 60, and 90 minutes of hypoxia. We continued reoxygenation for 120 minutes (in 60-minute and 90-minute hypoxia experiments) and subsequently tested reaction to 10(-4) mol/L norepinephrine. Apart from continuous recording of the contraction force, we measured the troponin I release into the tissue bath after ischemia and reoxygenation. RESULTS: Diazoxide exerted a negative inotropic effect in human atrial muscle (pD(2)=3.96 +/- 0.18). Both concentrations of diazoxide studied resulted in better functional recovery of atrial trabeculae subjected to 30 minutes of hypoxia. With longer hypoxia, only the higher diazoxide concentration provided significant protection as assessed by contractility. After 120 minutes of reoxygenation, only diazoxide-treated muscle was viable enough to respond to norepinephrine. Only 10(-4) mol/L diazoxide resulted in lower troponin I release during hypoxia and reoxygenation. CONCLUSIONS: This study shows that diazoxide provides significant concentration-dependent protection against hypoxia/reoxygenation injury to human myocardium in vitro.

Cell Hypoxia↗
PubMed2004

Minimally invasive mitral valve surgery -- first experience in Poland.

BACKGROUND: Minimally invasive cardiac surgery has been introduced to treat various cardiac disorders, predominantly ischaemic heart disease. Its usage in valvular disorders has been only recently proposed. AIM: To assess safety and efficacy of minimally invasive mitral valve surgery. METHODS: The procedure was performed in 10 patients (6 females, 4 males, mean age 59+/-7 years). All but one had preserved left ventricular ejection fraction. Two patients underwent mitral valvuloplasty, and mitral valve replacement was performed in all remaining cases. One procedure was a redo surgery following mitral commisurotomy. RESULTS: In all patients the procedure was effective. Prolongation of cardiopulmonary bypass and aorta cross-clamping time did not increase the complication rate which included one wound infection, one repeated cannulation of the femoral vessels and one minor stroke. Rehabilitation process seemed to be shorter than after standard procedures. CONCLUSIONS: Minimally invasive mitral valve surgery is a safe and alternative method of treatment, and is associated with excellent cosmetic results.

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