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| 2. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Evaluation of continuous and intermittent myocardial topical negative pressure.
- 2008
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Ingår i: Journal of Cardiovascular Medicine. - 1558-2027. ; 9:8, s. 813-819
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Topical negative pressure, commonly used in wound therapy, has been shown to increase blood flow and stimulate angiogenesis in subcutaneous tissue and skeletal muscle. In wound therapy, intermittent negative pressure is often preferred to continuous negative pressure as tissue exposed to intermittent therapy shows twice as much granulation tissue formation than that exposed to continuous pressure after 2 weeks of therapy. The present study was designed to elucidate the differences in microvascular blood flow in the left anterior descending artery area between continuous and intermittent myocardial topical negative pressure of -50 mmHg. METHODS: Six pigs underwent median sternotomy. Laser Doppler probes were inserted horizontally into the heart muscle in the left anterior descending artery area at depths of approximately 5-6 mm. Measurements of microvascular blood flow were performed in normal myocardium and ischemic myocardium during 20 min of countinuous and intermittent topical negative pressure at -50 mmHg. RESULTS: Both continuous and intermittent topical negative pressure of -50 mmHg significantly increased microvascular blood flow in the underlying myocardium: from 56.2 +/- 13.1 perfusion units (PU) before to 132.8 +/- 7.4 PU during countinuous topical negative pressure application (P < 0.05) and from 75.8 +/- 12.1 PU before to 153.6 +/- 4.7 PU during intermittent topical negative pressure application (P < 0.05). CONCLUSION: No statistically significant difference was found between microvascular blood flow during 20 min of continuous and intermittent topical negative pressure at -50 mmHg in this porcine model.
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| 3. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Impact of different topical negative pressure levels on myocardial microvascular blood flow.
- 2008
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Ingår i: Cardiovascular Revascularization Medicine. - : Elsevier BV. - 1878-0938 .- 1553-8389. ; 9:1, s. 29-35
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We have previously shown that a myocardial topical negative pressure (TNP) of -50 mmHg significantly increases microvascular blood flow in the underlying myocardium in normal, ischemic, and reperfused porcine myocardium. The present study was designed to elucidate the effect of different TNP levels between -50 and -150 mmHg on microvascular flow in normal and ischemic myocardium. MATERIALS AND METHODS: Seven pigs underwent median sternotomy. The microvascular blood flow in the myocardium was recorded, before and after the application of TNP, using laser Doppler velocimetry. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 min of LAD occlusion (ischemic myocardium). RESULTS: A TNP of -50 mmHg significantly increased microvascular blood flow in both normal (from 320.0+/-56.1 PU before TNP application to 435.7+/-65.5 PU after TNP application, P=.028) and ischemic myocardium (from 110.0+/-36.7 PU before TNP application to 194.3+/-56.2 PU after TNP application, P=.012). TNP between -75 and -150 mmHg showed no significant increase in microvascular blood flow in normal or ischemic myocardium. CONCLUSIONS: Of pressures between -50 and -150 mmHg, a TNP of -50 mmHg seems to be the most effective negative pressure concerning significant increase in microvascular blood flow in both normal and ischemic myocardium.
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| 4. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Topical negative pressure effects on coronary blood flow in a sternal wound model.
- 2008
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Ingår i: International Wound Journal. - 1742-481X. ; 5:4, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have suggested that mediastinitis is a strong predictor for poor long-term survival after coronary artery bypass surgery (CABG). In those studies, several conventional wound-healing techniques were used. Previously, we have shown no difference in long-term survival between CABG patients with topical negative pressure (TNP)-treated mediastinitis and CABG patients without mediastinitis. The present study was designed to elucidate if TNP, applied over the myocardium, resulted in an increase of the total amount of coronary blood flow. Six pigs underwent median sternotomy. The coronary blood flow was measured, before and after the application of TNP (-50 mmHg), using coronary electromagnetic flow meter probes. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 minutes of LAD occlusion (ischaemic myocardium). Normal myocardium: 171.3 +/- 14.5 ml/minute before to 206.3 +/- 17.6 ml/minute after TNP application, P < 0.05. Ischaemic myocardium: 133.7 +/- 18.4 ml/minute before to 183.2 +/- 18.9 ml/minute after TNP application, P < 0.05. TNP of -50 mmHg applied over the LAD region induced a significant increase in the total coronary blood flow in both normal and ischaemic myocardium.
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| 5. |
- Malmsjö, Malin, et al.
(författare)
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Negative-pressure wound therapy using gauze or open-cell polyurethane foam: similar early effects on pressure transduction and tissue contraction in an experimental porcine wound model.
- 2009
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Ingår i: Wound Repair and Regeneration. - 1524-475X. ; 17:2, s. 200-205
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Tidskriftsartikel (refereegranskat)abstract
- Negative-pressure wound therapy (NPWT), also known as topical negative-pressure therapy, is widely used to manage wounds and accelerate healing. NPWT has so far been delivered mainly via open-cell polyurethane foam, but increasing interest has been directed toward delivering NPWT via gauze. In the present study, the early effects of NPWT on pressure transduction and wound contraction were examined in wounds filled with either polyurethane foam or gauze. An experimental setup of a porcine wound model was used, in which the animals were anesthetized for 12-14 hours. Negative pressures between -50 and -175 mmHg were applied in -25 mmHg increments. Wound bed pressure was measured using a saline filled catheter sutured to the bottom of the wound. The contraction of the wound edges was also determined. The recordings were performed upon reaching steady state, which typically occurred within 1 minute. For both fillers, wound bed negative pressure increased linearly with delivered vacuum with little deviation from set pressure (correlation coefficient 0.99 in both cases). Similar tissue contraction was observed when using foam and gauze. The most prominent contraction was observed in the range of 0 to -50 mmHg with greater vacuum only producing minor further movement of the wound edge. In conclusion, the present experimental study shows that gauze and foam are equally effective at delivering negative pressure and creating mechanical deformation of the wound.
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| 6. |
- Mokhtari, Arash, et al.
(författare)
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The cost of vacuum-assisted closure therapy in treatment of deep sternal wound infection.
- 2008
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 42:1, s. 85-89
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Surgical sites infections are very expensive and the total costs for coronary artery bypass grafting (CABG) surgery followed by deep sternal wound infection (DSWI) with conventional therapy are estimated to be 2.8 times that for normal, CABG surgery. Promising results have been reported with vacuum-assisted closure (VAC) therapy in patients with DSWI. This study presents the cost of VAC therapy in patients with DSWI after CABG surgery. Design. Thirty-eight CABG patients with DSWI, between 2001 and 2005, were treated with VAC therapy. The cost of surgery, intensive care, ward care, laboratory tests and other costs were analyzed. Results. No three-month mortality or recurrent infection was observed. The average cost of CABG procedure and treatment of DSWI was 2.5 times higher than the mean cost of CABG alone. No significant correlations were found between the preoperative EuroSCORE and the cost of DSWI therapy. Conclusions. VAC therapy for patients who underwent CABG surgery followed by DSWI seems to be cost effective, and has low mortality rate.
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| 7. |
- Sjögren, Johan, et al.
(författare)
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Vakuumassisterad sår- behandling ger goda kliniska resultat God läkning vid komplicerade sår--djupa sternuminfektioner ett exempel.
- 2008
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Ingår i: Läkartidningen. - 0023-7205. ; 105:40, s. 2773-2776
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Tidskriftsartikel (refereegranskat)abstract
- acuum-assisted closure (V.A.C.®) is a novel treatment for wound healing, which has been used extensively during the last years in a growing number of clinical applications. This wound-healing technique is based on the application of local negative pressure to a wound. During treatment with vacuum-assisted closure, several beneficial wound healing mechanisms are initiated. Topical negative pressure increases the microvascular blood flow in the surrounding tissue and reduces wound tissue oedema and wound size. Furthermore, the stimulation of growth factors and neoangiogenesis facilitates the formation of granulation tissue in the wound. Vacuum-assisted closure has been widely adopted as a standard treatment for deep sternal wound infections following cardiac surgery since topical negative pressure combines several advantageous features from conventional surgical techniques. However, although it is effective, vacuum-assisted closure must always be used in combination with proper surgical revision and adequate antibiotic therapy in order to obtain optimal results.
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| 8. |
- Torbrand, Christian, et al.
(författare)
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Pressure transduction to the thoracic cavity during topical negative pressure therapy of a sternotomy wound.
- 2008
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Ingår i: International Wound Journal. - 1742-481X. ; 5:4, s. 579-584
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Tidskriftsartikel (refereegranskat)abstract
- The present study was performed to examine pressure transduction to the thoracic cavity during topical negative pressure (TNP) therapy of a sternotomy wound. Seven pigs underwent median sternotomy. Pressure transduction catheters were placed on the anterior surface of the heart (under the foam), in the pericardium (under the heart), in the left pleura and in the oesophagus at the level of the heart. The wound was sealed as for TNP therapy. The vacuum source was set to deliver negative pressures between -50 and -200 mmHg. The pressure on the anterior surface of the heart changed in a linear relationship with the applied negative pressure and was slightly lower than the applied negative pressure (-102 +/- 9 mmHg at delivered -125 mmHg). Further down in the thoracic cavity, in the pericardium (under the heart), in the left pleura and in the oesophagus, the wound pressure was only slightly affected by TNP therapy. In conclusion during TNP therapy, negative pressure is effectively transmitted to anterior portions of the heart. This may explain our recent findings that TNP increases microvascular blood flow in the myocardium. The pressure difference between the anterior and the posterior portions of the heart causes the right ventricle to be sucked up towards the posterior parts of the sternum, where it might be exposed to the sharp edges of the sternal bone, which may result in heart injury.
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| 9. |
- Hou, Mingyan, et al.
(författare)
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Increase in cardiac P2X1-and P2Y2-receptor mRNA levels in congestive heart failure
- 1999
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Ingår i: Life Sciences. - 1879-0631. ; 65:11, s. 1195-1206
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Tidskriftsartikel (refereegranskat)abstract
- We wanted to study the expression of P2-receptors at the mRNA-level in the heart and if it is affected by congestive heart failure (CHF). To quantify the P2 receptor mRNA-expression we used a competitive RT-PCR protocol which is based on an internal RNA standard. The P2 receptor mRNA-expression was quantified in hearts from CHF rats and compared to sham-operated rats. Furthermore, the presence of receptor mRNA was studied in the myocardium from patients with heart failure. In the sham operated rats the G-protein coupled P2Y-receptors were expressed at a higher level than the ligand gated ion-channel receptor (P2X1). Among the P2Y-receptors the P2Y6-receptor was most abundantly expressed (P2Y6 > P2Y1 > P2Y2 = P2Y4 > P2X1). A prominent change was seen for the P2X1- and P2Y2-receptor mRNA levels which were increased 2.7-fold and 4.7-fold respectively in the myocardium from the left ventricle of CHF-rats. In contrast, the P2Y1-, P2Y4- and P2Y6-receptor mRNA levels were not significantly altered in CHF rats. In human myocard the P2X1-, P2Y1-, P2Y2-, P2Y6- and P2Y11-receptors were detected by RT-PCR in both right and left atria and ventricles, while the P2Y4-receptor band was weak or absent. In conclusion, most of the studied P2-receptors were expressed in both rat and human hearts. Furthermore, the P2X1- and P2Y2-receptor mRNA were upregulated in CHF, suggesting a pathophysiological role for these receptors in the development of heart failure.
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| 10. |
- Malmsjö, Malin, et al.
(författare)
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Characterization of contractile P2 receptors in human coronary arteries by use of the stable pyrimidines uridine 5'-O-thiodiphosphate and uridine 5'-O-3-thiotriphosphate
- 2000
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - 1521-0103. ; 293:3, s. 755-760
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Tidskriftsartikel (refereegranskat)abstract
- The present study was designed to evaluate the relative contribution of the different contractile P2 receptors in endothelium-denuded human coronary arteries by use of extracellular nucleotides, including the stable pyrimidines uridine 5'-O-3-thiotriphosphate (UTPgammaS) and uridine 5'-O-thiodiphosphate (UDPbetaS). The isometric tension of isolated vessel segments was recorded in vitro, and P2 receptor mRNA expression was examined by reverse transcription-polymerase chain reaction. alphabeta-Methylene-adenosine triphosphate (alphabeta-MeATP) elicited contractions at a low concentration (pEC(50) = 5.2), indicating the presence of contractile P2X receptors. The P2Y responses were analyzed after P2X receptor desensitization with 10 microM alphabeta-MeATP. The stable nucleotides UTPgammaS and adenosine 5'-O-3-thiotriphosphate (ATPgammaS), which are agonists of P2Y(2) or P2Y(4) receptors, were approximately 2 log units more potent than the endogenous UTP and ATP (pEC(50) = 4.6 and 3.8 for UTPgammaS and ATPgammaS). The efficacy of these responses were approximately double that of the P2X agonist alphabeta-MeATP (E(max) = 125% for UTPgammaS, 126% for ATPgammaS, and 68% for alphabeta-MeATP), suggesting a primary role for contractile P2Y(2/4) receptors. The P2Y(2) receptor agonist diadenosine tetraphosphate also stimulated contraction, whereas the selective P2Y(1) agonist adenosine 5'-O-thiodiphosphate and the selective P2Y(6) agonist UDPbetaS had no effect. Reverse transcription-polymerase chain reaction analysis of mRNA from endothelium-denuded human coronary arteries demonstrated strong bands for P2Y(2) and P2X(1), although bands for P2Y(1), P2Y(4), and P2Y(6) receptor mRNA could also be detected. In conclusion, the stable pyrimidines UDPbetaS and UTPgammaS are important tools for P2 receptor subtype characterization in intact tissues with ectonucleotidase activity. Extracellular nucleotides elicit contraction of human coronary arteries primarily by activation of P2Y(2) and P2X receptors, whereas a role for P2Y(1) and P2Y(6) receptors can be excluded. Antagonists of P2Y(2) and P2X receptors may be useful in the treatment of coronary vasospastic disorders.
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