| 1. |
- Ahlsson, Anders, 1962-, et al.
(author)
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Positioning of the ablation catheter in total endoscopic ablation
- 2014
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In: Interactive Cardiovascular and Thoracic Surgery. - : Oxford University Press. - 1569-9293 .- 1569-9285. ; 18:1, s. 125-127
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Journal article (peer-reviewed)abstract
- Minimally invasive ablation of atrial fibrillation is an option in patients not suitable for or refractory to catheter ablation. Total endoscopic ablation can be performed via a monolateral approach, whereby a left atrial box lesion is created. If the ablation is introduced from the right side, the positioning of the ablation catheter on the partly hidden left pulmonary veins is of vital importance. Using thoracoscopy in combination with multiplane transoesophageal echocardiography, the anatomical position of the ablation catheter can be established. Our experience in over 60 procedures has confirmed this to be a safe technique of total endoscopic ablation.
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| 2. |
- Arbeus, Mikael, et al.
(author)
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Milrinone Increases Flow in Coronary Artery Bypass Grafts After Cardiopulmonary Bypass : A Prospective, Randomized, Double-Blind, Placebo-Controlled Study
- 2009
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In: Journal of Cardiothoracic and Vascular Anesthesia. - : Elsevier BV. - 1053-0770 .- 1532-8422. ; 23:1, s. 48-53
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Journal article (peer-reviewed)abstract
- Objective: To compare the effects of a bolus of milrinone, 50 mu g/kg, versus placebo on flow in coronary artery bypass grafts after cardiopulmonary bypass (CPB). Design: A prospective, randomized, double-blind study. Setting: A university hospital. Participants: Forty-four patients with stable angina and left ventricular ejection fraction > 30% scheduled for elective coronary artery bypass graft (CABG) surgery were included. Intervention: Patients were randomized to receive 50 mu g/kg of milrinone (n = 22) or placebo (n = 22) after aortic declamping. Measurements and Main Results: The flow in coronary artery bypass grafts was measured with a transit time flow meter at 10 minutes and 30 minutes after termination of CPB. The hemodynamic evaluation included transesophageal echocardiography, mean arterial pressure (MAP), heart rate, and intracavitary measurement of left ventricular end-diastolic pressure (LVEDP). The flow in the saphenous vein grafts was significantly higher in the milrinone group when compared with the placebo group both at 10 and 30 minutes after termination of CPB (p < 0.001). At 10 minutes, the flow was 64.5 +/- 37.4 mL/min (mean +/- standard deviation) and 43.6 +/- 25.7 mL/min in nonsequential vein grafts for milrinone and placebo, respectively. Corresponding values at 30 minutes were 54.8 +/- 29.9 mL/min and 35.3 +/- 22.4 mL/min. The left internal thoracic artery (LITA) flow was higher in the milrinone group but did not reach statistical significance. The fractional area change was higher, and the MAP and calculated pressure gradient (MAP-LVEDP) were lower at 10 minutes in the milrinone group. Conclusion: Milrinone significantly increases the flow in anastomosed saphenous vein grafts after CPB, and has beneficial effects on left ventricular function.
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| 3. |
- Axelsson, Birger
(author)
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Byggherrekostnadernas utveckling 2015-2020
- 2020
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Reports (other academic/artistic)abstract
- Bakgrunden till denna rapport är de höga priserna och höga hyrorna i nyproducerade bostäder. Debatten fokuserar ofta på markpriser och de direkta byggkostnaderna, men i denna rapport behandlas (delar av) det som kallas byggherrekostnader.Begreppet har ingen enhetlig definition och i denna rapport fokuseras på kommunala planoch bygglovsavgifter som anslutningsavgifter för vatten och avlopp samt el. I byggherrekostnader kan man även räkna in olika skatter och kostnaderna för det egna arbete som byggherren lägger ner, men de behandlas inte här.Data har samlats in från kommuner geografiskt spridda över landet och med olika storlek, rörande avgifterna år 2015 och 2020. Det rör avgifter för styckebyggda småhus i en viss antagen storlek, densamma vid båda tidpunkterna (tomtarea 800 kvm och boyta 160 kvm). Därutöver har kompletterande intervjuer med kommunala tjänstemän och en enklare litteraturstudie genomförts i försök att besvara vad som kan förklara byggherrekostnadernas utveckling.Att jämföra prisutvecklingen med Konsumentprisindex (KPI) kan vara orättvist eftersom fallande importpriser påverkat den senare. Tjänsteprisindex (TPI) bedömdes därför som lämpligare och TPI steg under den aktuella perioden med 7%.I de studerade kommunerna har plan- och bygglovsavgifter ökat med 10% under perioden, från i genomsnitt ca 110 000 kr till ca 120 000 kr. VA-anslutningsavgifter har ökat med 20%, från drygt 140 000 kr till drygt 170 000 kr. Elanslutningsavgifterna har utvecklats på liknande sätt, från knappt 25 000 kr till drygt 35 000 kr. Rapporten visar att byggherrekostnadernas utveckling har varit kraftigt negativ i vissa utvalda kommuner, och på motsatt sätt, kraftigt positiv i andra kommuner. Ett exempel är Sundbybergs kommun, vars plan- och bygglovsavgifter har minskat med 31%. Samtidigt har t.ex. Haninge kommun ökat motsvarande avgifter med 40%. Dessa procentsatser indikerar att avgifterna påverkas av förd politik i den aktuella kommunen.Rapporten visar att det finns flera möjliga rationella skäl bakom ökningen, men att det samtidigt inte går att försumma att ökningarna i kommunernas avgifter skulle kunna bero på ineffektivitet och missbruk av dominerande ställning. Det är tydligt att utformningen av kommunala taxor är komplex till sin natur, där en mängd faktorer behöver tas i beaktning för att motivera taxans storlek. Arbetet med de kommunala taxorna har visat sig vara en kontinuerligt pågående process. Till syvende och sist så ska dock taxans storlek utformas utifrån hur kostnaderna ser ut för kommunen. Det är bevisligen så att flera kommuner uppfattar prissättningen som komplex. Aktörer som SKR bär därför ett stort ansvar för att kunna bistå kommuner i att räkna ut rätt taxa. Av denna anledning så påpekas det i rapporten att själva prissättningsprocessen bör utredas närmare.Därutöver föreslås det i rapporten att SKR, t.ex. genom webbtjänsten Kolada, bör samla och presentera kommunala PBL-taxor över tid. En av anledningarna till varför SKR bör göra detta är de bevisliga svårigheterna i att hämta information om PBL-taxor från kommuner över tid.
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| 4. |
- Axelsson, Birger, 1957-
(author)
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Cardiac effects of non-adrenergic inotropic drugs : clinical and experimental studies
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Background: Myocardial failure and dysfunction is not uncommon during critical illness and following cardiac surgery. For optimal treatment, a better understanding of the effects of inotropic drugs is needed. In this thesis, two non-adrenergic mediated inotropes, milrinone and levosimendan were studied in different models of myocardial dysfunction. The study aims were to assess the following: the effects of milrinone on blood flow in coronary artery bypass grafts during CABG surgery; the effects of milrinone on left ventricular diastolic function during post-ischaemic myocardial dysfunction; whether milrinone or levosimendan are protective or injurious during acute myocardial ischaemia, and if levosimendan potentiates myocardial function when added to milrinone in an experimental model of post-ischaemic (stunned) myocardium.Material and Methods: In Study I, 44 patients undergoing coronary artery bypass surgery(CABG) were included as subjects. Milrinone or saline was administrated in a single dose during cardio-pulmonary bypass (CPB) and coronary graft flow measurements were recorded after 10 and 30 min following CPB. In Study II; 24 patients undergoing CABG had estimations of peak ventricular filling rates made before and after CPB with administration of milrinone or saline as a single dose during CPB, performed by assessment of the rate of change in diastolic cross-sectional left ventricular area. In Study III, energy-metabolic effects of milrinone and levosimendan were measured in an anaesthetized porcine model during 45 minutes of regional myocardial ischemia. Microdialysis sampling of metabolites of local ischemic metabolism allowed assessment of glycolytic activity and the degree of myocardial calcium overload. In Study IV, in a porcine model of postischaemic myocardial stunning, ventricular pressure-volume relationships were analyzed when milrinone or a combination of milrinone and levosimendan were given together.Results: In Study I, there was a clear increase in non-sequential saphenous vein graft blood flow with milrinone at 10 minutes (64.5 ± 37.4 compared to placebo 43.6 ± 25.7 ml/min (mean ± SD).). A decreasing but still measureable flow increase was seen for milrinone at 30 minutes. In Study II, an increase in early left ventricular filling rate (ventricular cross-sectional area rate of change,dA/dt) was seen in the milrinone treated group. Pre-bypass milrinone group dA/dt 22.0 ± 9.5 changed to post-bypass values dA/dt 27.8 ± 11.5 cm2/sec). Placebo group pre-bypass dA/dt was 21.0 ± 8.7 and post-bypass 17.1 ± 7.1 cm2/sec. A milrinone effect was demonstrated in an adjusted regression model (p = 0.001). In Study III, neither milrinone nor levosimendan led to a change in energy-metabolic activity during ischemia as reflected by interstitial glucose, pyruvate, lactate orglycerol. Neither drug exacerbated the relative myocardial calcium overload during ischemia. In Study IV, milrinone improved active relaxation (tau) in post-ischemic stunned myocardium, but did not markedly improve systolic function by preload recruitable stroke work. Levosimendan added to milrinone showed minimal effect on active relaxation but a positive effect on systolic function in combination with milrinone.Conclusions: We conclude that milrinone treatment leads to an increase in blood flow in newly implanted coronary saphenous vein grafts, and improves ventricular relaxation post-cardiopulmonary bypass. Neither milrinone nor levosimendan, in this porcine model, negatively influence myocardial energy metabolism or calcium overload during acute ischaemia. Addition of levosimendan to milrinone treatment during post-ischaemic ventricular dysfunction may provide additive inotropic effects on systolic function but probably not for active relaxation.
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| 5. |
- Axelsson, Birger, 1957-, et al.
(author)
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Effects of Combined Milrinone and Levosimendan Treatment on Systolic and Diastolic Function During Postischemic Myocardial Dysfunction in a Porcine Model
- 2016
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In: Journal of Cardiovascular Pharmacology and Therapeutics. - Thousand Oaks, USA : Sage Publications. - 1074-2484 .- 1940-4034. ; 21:5, s. 495-503
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Journal article (peer-reviewed)abstract
- It is not known whether there are positive or negative interactions on ventricular function when a calcium-sensitizing inotrope is added to a phosphodiesterase inhibitor in the clinical setting of acute left ventricular (LV) dysfunction. We hypothesized that when levosimendan is added to milrinone treatment, there will be synergetic inotropic and lusitropic effects. This was tested in an anesthetized porcine postischemic global LV injury model, where ventricular pressures and volumes (conductance volumetry) were measured. A global ischemic injury was induced by repetitive left main stem coronary artery occlusions. Load-independent indices of LV function were assessed before and after ventricular injury, after milrinone treatment, and finally after addition of levosimendan to the milrinone treatment. Nonparametric, within-group comparisons were made. The protocol was completed in 12 pigs, 7 of which received the inotrope treatment and 5 of which served as controls. Milrinone led to positive lusitropic effects seen by improvement in tau after myocardial stunning. The addition of levosimendan to milrinone further increased lusitropic state. The latter effect could however not be attributed solely to levosimendan, since lusitropic state also improved spontaneously in time-matched controls at the same rate during the corresponding period. When levosimendan was added to milrinone infusion, there was no increase in systolic function (preload recruitable stroke work) compared to milrinone treatment alone. We conclude that in this model of postischemic LV dysfunction, there appears to be no clear improvement in systolic or diastolic function after addition of levosimendan to established milrinone treatment but also no negative effects of levosimendan in this context.
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| 6. |
- Axelsson, Birger, 1957-, et al.
(author)
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Milrinone and levosimendan during porcine myocardial ischemia : no effects on calcium overload and metabolism
- 2013
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In: Acta Anaesthesiologica Scandinavica. - : John Wiley & Sons. - 0001-5172 .- 1399-6576. ; 57:6, s. 719-728
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Journal article (peer-reviewed)abstract
- Background: Although inotropic stimulation is considered harmful in the presence of myocardial ischaemia, both calcium sensitisers and phosphodiesterase inhibitors may offer cardioprotection. We hypothesise that these cardioprotective effects are related to an acute alteration of myocardial metabolism. We studied in vivo effects of milrinone and levosimendan on calcium overload and ischaemic markers using left ventricular microdialysis in pigs with acute myocardial ischaemia.Methods: Anaesthetised juvenile pigs, average weight 36kg, were randomised to one of three intravenous treatment groups: milrinone 50g/kg bolus plus infusion 0.5g/kg/min (n=7), levosimendan 24g/kg plus infusion 0.2g/kg/min (n=7), or placebo (n=6) for 60min prior to and during a 45min acute regional coronary occlusion. Systemic and myocardial haemodynamics were assessed, and microdialysis was performed with catheters positioned in the left ventricular wall. 45Ca2+ was included in the microperfusate in order to assess local calcium uptake into myocardial cells. The microdialysate was analysed for glucose, lactate, pyruvate, glycerol, and for 45Ca2+ recovery.Results: During ischaemia, there were no differences in microdialysate-measured parameters between control animals and milrinone- or levosimendan-treated groups. In the pre-ischaemic period, arterial blood pressure decreased in all groups while myocardial oxygen consumption remained stable.Conclusions: These findings reject the hypothesis of an immediate energy-conserving effect of milrinone and levosimendan during acute myocardial ischaemia. On the other hand, the data show that inotropic support with milrinone and levosimendan does not worsen the metabolic parameters that were measured in the ischaemic myocardium.
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| 7. |
- Axelsson, Birger, et al.
(author)
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Milrinone improves diastolic function in coronary artery bypass surgery as assessed by acoustic quantification and peak filling rate : a prospective randomized study
- 2010
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In: Journal of Cardiothoracic and Vascular Anesthesia. - : Elsevier BV. - 1053-0770 .- 1532-8422. ; 24:2, s. 244-249
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To compare the effects of a bolus dose of milrinone, 50 microg/kg, to placebo on diastolic function (active relaxation) in patients undergoing on-pump coronary artery bypass grafting (CABG).DESIGN: Prospective, randomized, double-blind, placebo-controlled study.SETTING: University hospital.PARTICIPANTS: Twenty-four patients with stable angina and left ventricular ejection fraction >30%, scheduled for elective CABG using cardiopulmonary bypass (CPB), were included.INTERVENTION: Patients were randomized to receive either 50 microg/kg of milrinone (n = 12) or placebo (n = 12) after aortic declamping.MEASUREMENTS AND MAIN RESULTS: The diastolic function of the left ventricle (LV) was measured as peak filling rate (dA/dt [maximal diastolic area change over time]) with transesophageal echocardiography (TEE) using acoustic quantification (AQ) before CPB and 10 minutes after termination of CPB. The normalized peak filling rate (dA/dt)/EDA was also calculated. Active relaxation was statistically significantly increased in the milrinone group compared with the placebo group after CPB.CONCLUSION: Patients undergoing CABG surgery and treated with milrinone after aortic declamping had better diastolic function following cardiopulmonary bypass.
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| 8. |
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| 9. |
- Axelsson, Birger, et al.
(author)
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The effect of quantitative easing and quantitative tightening on U.S. equity REIT returns
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Other publication (other academic/artistic)abstract
- The Federal Reserve (the Fed) has implemented several quantitative easing (QE) programmes to stimulate the U.S. economy and increase the inflation rate after the great financial crisis (GFC) and the COVID-19 crisis. However, when the inflation rate started to increase steeply in 2021, the Fed instead begun to implement quantitative tapering (QT) to cool down the U.S. economy and bring back inflation to it target rate. This study seeks to estimate the effect of the QE and QT programmes on the U.S. equity Real Estate Investment Trusts (REITs) index returns, while controlling for several other important macro-financial factors. The estimations show that the QE programmes significantly contributed to a long period of positive REIT returns, while the recent 2022 QT efforts has contributed significantly to the recent period of negative REIT returns. We also find that the increases in the key macro-financial factors Baa Corporate Bond Yield ad the CBOE volatility index of the U.S. stock market (VIX) result in lower REIT returns, while increases in total bank equity capital of FDIC-Insured Commercial Banks and Savings Institutions contribute to positive REIT returns. We also find that the negative initial REIT return reaction to the COVID-19 outbreak was likely outperformed by the positive impacts of the large combined monetary (QE) and fiscal stimulus packages implemented after the outbreak of the COVID-19 crisis. The findings of this study show that REIT returns are highly sensitive to profound QE and QT programmes through important monetary transmission mechanisms channels such as the interest rate, asset price and risk-taking channels. This research supports REIT investors to understand how the Fed's monetary policy actions, particularly QE and QT programmes, impact the returns of the REIT index, and to adjust their investment strategies accordingly based on their expectations of future monetary policy actions and macro-financial conditions.
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| 10. |
- Axelsson, Birger, et al.
(author)
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Univariate Forecasting for REITs with Deep Learning: A Comparative Analysis with an ARIMA Model
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Other publication (other academic/artistic)abstract
- This study aims to investigate whether the newly developed deep learning-based algorithms, specifically Long-Short Term Memory (LSTM), outperform traditional algorithms in forecasting Real Estate Investment Trust (REIT) returns. The empirical analysis conducted in this research compares the forecasting performance of LSTM and Autoregressive Integrated Moving Average (ARIMA) models using out-of-sample data. The results demonstrate that in general, the LSTM model does not exhibit superior performance over the ARIMA model for forecasting REIT returns. While the LSTM model showed some improvement over the ARIMA model for shorter forecast horizons, it did not demonstrate a significant advantage in the majority of forecast scenarios, including both recursive multi-step forecasts and rolling forecasts. The comparative evaluation reveals that neither the LSTM nor ARIMA model demonstrated satisfactory performance in predicting REIT returns out-of-sample for longer forecast horizons. This outcome aligns with the efficient market hypothesis, suggesting that REIT returns may exhibit a random walk behavior. While this observation does not exclude other potential factors contributing to the models' performance, it supports the notion of the presence of market efficiency in the REIT sector. The error rates obtained by both models were comparable, indicating the absence of a significant advantage for LSTM over ARIMA, as well as the challenges in accurately predicting REIT returns using these approaches. These findings emphasize the need for careful consideration when employing advanced deep learning techniques, such as LSTM, in the context of REIT return forecasting and financial time series. While LSTM has shown promise in various domains, its performance in the context of financial time series forecasting, particularly with a univariate regression approach using daily data, may be influenced by multiple factors. Potential reasons for the observed limitations of our LSTM model, within this specific framework, include the presence of significant noise in the daily data and the suitability of the LSTM model for financial time series compared to other problem domains. However, it is important to acknowledge that there could be additional factors that impact the performance of LSTM models in financial time series forecasting, warranting further investigation and exploration. This research contributes to the understanding of the applicability of deep learning algorithms in the context of REIT return forecasting and encourages further exploration of alternative methodologies for improved forecasting accuracy in this domain.
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