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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Cost-effectiveness and Value of Further Research of Treatment Strategies for Cardiovascular Disease

Henriksson, Martin January 2007 (has links)
Economic evaluations provide a tool to estimate costs and health consequences of competing medical technologies, ultimately to aid decision makers when deciding which medical technologies should be funded from available resources. Such decisions inevitably need to be taken under uncertainty and it is not clear how to approach them in health care decision-making. Recent work in economic evaluation has proposed an analytic framework where two related, but conceptually different decisions need to be considered: (1) should a medical technology be adopted given existing evidence; and (2) whether more evidence should be acquired to support the adoption decision in the future. The proposed analytic framework requires a decision-analytic model appropriately representing the clinical decision problem under consideration, a probabilistic analysis of this model in order to determine cost-effectiveness and characterise current decision uncertainty, and estimating the value of additional information from research to reduce decision uncertainty. The main aim of this thesis is to apply the analytic framework on three case studies concerning treatment strategies for cardiovascular disease in order to establish whether the treatment strategies should be adopted given current available information and if more information should be acquired to support the adoption decisions in the future. The implications for policy and methodology of utilising the analytic framework employed in the case studies are also discussed in this thesis. The results of the case studies show that a screening programme for abdominal aortic aneurysm in 65-year-old men is likely to be cost-effective in a Swedish setting and there appears to be little value in performing further research regarding this decision problem; an early interventional strategy in non-ST-elevation acute coronary syndrome is cost-effective for patients at intermediate to high risk of further cardiac events in a UK setting; endarterectomy in patients with an asymptomatic carotid artery stenosis is cost-effective for men around 73 years of age or younger in a Swedish setting and conducting further research regarding this decision problem is potentially worthwhile. Comparing the results of the present analyses with current clinical practice shows a need for changing clinical practice in Sweden regarding screening for abdominal aortic aneurysm and endarterectomy in patients with asymptomatic carotid artery stenosis. Furthermore, employing the analytic framework applied in the case studies can improve treatment guidelines and recommendations for further research. In particular, treatment guidelines ought to consider in which particular subgroups of patients an intervention is cost-effective. The case studies indicate that it is feasible to apply the analytic framework for economic evaluation of health care. Methodological development can improve the accuracy with which cost-effectiveness and value of information is estimated, but may also lead to comprehensive and complex evaluations. The nature of the decision problem should determine the level of comprehensiveness required for a particular evaluation.
12

Μελέτη της αντιδραστικότητας των αιμοπεταλίων σε ασθενείς με STEMI που υποβάλλονται σε πρωτογενή αγγειοπλαστική μετά από δόση φόρτισης με κλοπιδογρέλη

Θεοδωρόπουλος, Κωνσταντίνος 07 June 2013 (has links)
Με δεδομένο το γεγονός ότι η αιμοπεταλιακή αναστολή είναι θεμελιώδους σημασίας σε ασθενείς με οξύ έμφραγμα του μυοκαρδίου με ανάσπαση του ST τμήματος που υποβάλλονται σε πρωτογενή αγγειοπλαστική (PPCI), η αναγνώριση παραγόντων που σχετίζονται με την εμφάνιση στην οξεία φάση υψηλής αντιδραστικότητας των αιμοπεταλίων (HTPR) παρά τη θεραπεία με κλοπιδογρέλη μπορεί να είναι σημαντική. Σε ασθενείς με STEMI και επακόλουθη PPCI εκτιμήθηκε η αιμοπεταλιακή αντιδραστικότητα 2 ώρες μετά τη φόρτιση με 600mg κλοπιδογρέλης με τη χρήση της παρακλίνιας μεθόδου VerifyNow P2Y12. Το όριο ≥235 P2Y12 μονάδων αντιδραστικότητας (PRU) θεωρήθηκε ενδεικτικό HTPR. Από τους 92 ασθενείς με STEMI, 63 (68,5%) βρέθηκαν να έχουν υψηλή αιμοπεταλιακή αντιδραστικότητα στις 2 ώρεςμετά τη φόρτιση. Οι ασθενείς με την υψηλή αντιδραστικότητα είχαν λάβει ‘πρώιμη φόρτιση’ με κλοπιδογρέλη πιο συχνά, είχαν χαμηλότερη τιμή αιμοσφαιρίνης και έτειναν να έχουν επηρεασμένη νεφρική λειτουργία σε σε σχέση με αυτούς που είχαν ικανοποιητική απάντηση στην κλοπιδογρέλη. Στην πολυπαραγοντική ανάλυση, η ‘πρώιμη φόρτιση’ και η κάθαρση κρεατινίνης <60ml/min είχαν ανεξάρτητη συσχέτιση με υψηλότερο κίνδυνο εμφάνισης HTPR (σχετικός κίνδυνος [RR]=1,55 95% διάστημα εμπιστοσύνης [CI]:1,11-2,17 P=0,01 και RR=1,31 95% CI: 1,008-1,71 P=0,04 αντίστοιχα). Επομένως σε ασθενείς με STEMI που υποβάλλονται σε PPCI, η ‘πρώιμη φόρτιση’ με κλοπιδογρέλη και η επηρεασμένη νεφρική λειτουργία αποτελούν ανεξάρτητους προβλεπτικούς παράγοντες εμφάνισης υψηλής υπολειπόμενης αντιδραστικότητας των αιμοπεταλίων (εκτιμούμενης με τη μεθοδο VerifyNow) 2 ώρες μετά την αρχική φόρτιση με 600mg κλοπιδογρέλης / Given that platelet inhibition is crucial when ST-elevation myocardial infarction (STEMI) patients undergo primary PCI (PPCI), the identification of factors associated with early high on-treatment platelet reactivity may be important. Consecutive STEMI patients admitted for PPCI were considered for platelet reactivity assessment 2 h after loading with 600 mg clopidogrel using the VerifyNow point-of-care P2Y12 assay. A cut-off of ≥235 P2Y12 reaction units indicated high on-treatment platelet reactivity. Out of 92 STEMI patients, 63 (68.5%) were found to have high on-treatment platelet reactivity. Patients with high on-treatment platelet reactivity had received upstream clopidogrel loading more frequently, had lower admission hemoglobin and tended to have an impaired renal function compared to those with an adequate response to clopidogrel. On multivariate analysis, upstream clopidogrel loading and creatinine clearance <60 ml/min were independently associated with higher risk for high on-treatment platelet reactivity (relative risk [RR]=1.55, 95% confidence interval [CI]: 1.11–2.17, P=0.01; RR=1.31, 95% CI: 1.008–1.71, P=0.04, respectively). In patients with STEMI undergoing PPCI, use of upstream clopidogrel and impaired renal function independently predict high on-treatment platelet reactivity assessed as early as 2 h following 600 mg of clopidogrel loading dose on point-of-care P2Y12 function assay.
13

Prognosis after ST-elevation myocardial infarction: a study on cardiac magnetic resonance imaging versus clinical routine

de Waha, Suzanne, Eitel, Ingo, Desch, Steffen, Fuernau, Georg, Lurz, Philipp, Stiermaier, Thomas, Blazek, Stephan, Schuler, Gerhard, Thiele, Holger January 2014 (has links)
Background: This study aimed to evaluate the incremental prognostic value of infarct size, microvascular obstruction (MO), myocardial salvage index (MSI), and left ventricular ejection fraction (LV-EFCMR) assessed by cardiac magnetic resonance imaging (CMR) in comparison to traditional outcome markers in patients with ST-elevation myocardial infarction (STEMI) reperfused by primary percutaneous intervention (PCI). Methods: STEMI patients reperfused by primary PCI (n = 278) within 12 hours after symptom onset underwent CMR three days after the index event (interquartile range [IQR] two to four). Infarct size and MO were measured 15 minutes after gadolinium injection. T2-weighted and contrast-enhanced CMR were used to calculate MSI. In addition, traditional outcome markers such as ST-segment resolution, pre- and post-PCI Thrombolysis In Myocardial Infarction (TIMI)-flow, maximum level of creatine kinase-MB, TIMI-risk score, and left ventricular ejection fraction assessed by echocardiography were determined in all patients. Clinical follow-up was conducted after 19 months (IQR 10 to 27). The primary endpoint was defined as a composite of death, myocardial reinfarction, and congestive heart failure (MACE). Results: In multivariable Cox regression analysis, adjusting for all traditional outcome parameters significantly associated with the primary endpoint in univariable analysis, MSI was identified as an independent predictor for the occurrence of MACE (Hazard ratio 0.94, 95% CI 0.92 to 0.96, P <0.001). Further, C-statistics comparing a model including only traditional outcome markers to a model including CMR parameters on top of traditional outcome markers revealed an incremental prognostic value of CMR parameters (0.74 versus 0.94, P <0.001). Conclusions: CMR parameters such as infarct size, MO, MSI, and LV-EFCMR add incremental prognostic value above traditional outcome markers alone in acute reperfused STEMI.
14

A prospective observational study to investigate the effect of prehospital airway management strategies on mortality and morbidity of patients who experience return of spontaneous circulation post cardiac arrest and are transferred directly to regional Heart Attack Centres by the Ambulance Service

Edwards, Timothy Robin January 2017 (has links)
Introduction: The most appropriate airway management technique for use by paramedics in out-of-hospital cardiac arrest is yet to be determined and evidence relating to the influence of airway management strategy on outcome remains equivocal. In cases where return of spontaneous circulation (ROSC) occurs following out-of-hospital cardiac arrest, patients may undergo direct transfer to a specialist heart attack centre (HAC) where the post resuscitation 12 lead ECG demonstrates evidence of ST elevation myocardial infarction. To date, no studies have investigated the role of airway management strategy on outcomes in this sub-set of patients. The AMICABLE (Airway Management In Cardiac Arrest, Basic, Laryngeal mask airway, Endotracheal intubation) study therefore sought to investigate the influence of prehospital airway management strategy on outcomes in patients transferred by the ambulance service directly to a HAC post ROSC. Methods: Adults with ROSC post out-of-hospital cardiac arrest who met local criteria for transfer to a HAC were identified prospectively. Ambulance records were reviewed to determine prehospital airway management approach and collect physiological and demographic data. HAC notes were obtained to determine in-hospital course and quantify neurological outcome via the Cerebral Performance Category (CPC) scale. Neurologically intact survivors were contacted post discharge to assess quality of life via the SF-36 health survey. Statistical analyses were performed via Chi-square, Mann Whitney U test, odds ratios, and binomial logistic regression. Results: A total of 220 patients were recruited between August 2013 and August 2014, with complete outcome data available for 209. The age of patients ranged from 22-96 years and 71.3% were male (n=149). Airway management was undertaken using a supraglottic airway (SGA) in 72.7% of cases (n=152) with the remainder undergoing endotracheal intubation (ETI). There was no significant difference in the proportion of patients with good neurological outcome (CPC 1&2) between the SGA and ETI groups (p=.286). Similarly, binomial logistic regression incorporating factors known to influence outcome demonstrated no significant difference between the SGA and ETI groups (Adjusted OR 0.725, 95% CI 0.337-1.561). Clinical and demographic variables associated with good neurological outcome included the presence of a shockable rhythm (p < .001), exposure to angiography (p < .001), younger age (p < .001) and shorter time to ROSC (p < .001). Due to an inadequate response rate (25.4%, n=15) analysis of SF36 data was limited to descriptive statistics. Limitations: The study only included patients who achieved ROSC and met the criteria for direct transfer to a HAC. Results are therefore not generalisable to more heterogenous resuscitation populations. Accuracy of clinical decision making and ECG interpretation were not assessed and therefore some patients included in the study may have been inappropriately transferred to a HAC. The low SF-36 survey response rate limited the level of neurological outcome analysis that could be undertaken. Conclusion: In this study, there was no significant difference in the proportion of good neurological outcomes in patients managed with SGA versus ETI during cardiac arrest. Further research incorporating randomised controlled trials is required to provide more definitive evidence in relation to the optimal airway management strategy in out-of-hospital cardiac arrest.
15

Fokussierte transthorakale Echokardiographie bei Patienten mit akutem Koronarsyndrom (ACS) in der präklinischen Notfallmedizin / Focused transthoracic echocardiography in patients with acute coronary syndrome (ACS) in preclinical emergency medicine

Teut, Elena Dominique Maria 11 May 2020 (has links)
No description available.
16

Automatická detekce infarktu myokardu v signálu EKG / Automatic detection of myocardial infarction in ECG

Nejedlý, Lukáš January 2018 (has links)
This master’s thesis deals with the automatic detection of myocardial infarction in ECG. Semester work consists of two parts. The theoretical part provides a description of the electrical conduction system of the heart, spreading of electrical activity through the heart muscle, the methods of ECG scanning and the ECG curve. There are also mentioned the causes of myocardial ischemia and various methods of its detection. Another part is devoted to high-frequency ECG, analysis of HFQRS and clinical studies which describe the use of high-frequency ECG in diagnosis of myocardial infarction. In the practical part is proposed an algorithm using low-frequency components ECG and an algorithm using high-frequency components ECG for automatic detection of myocardial infarction. The proposed algorithms are implemented in programming environment MATLAB and tested on signals from the PTB database. The final part of the master‘s thesis is devoted to the comparison of the success of myocardial infarction by means of low frequency and high frequency components of ECG and comparison of achieved results with results from clinical studies.
17

Širina QRS kompleksa kao elektrokardiografski prediktor reperfuzije nakon primarne perkutane koronarne intervencije i veličine akutnog infarkta miokarda sa ST elevacijom / The Duration Of QRS Complex As Electrocardiographic Predictor Of Reperfusion After Primary Percutaneous Coronary Intervention And The Size Of Acute St-Elevation Myocardial Infarction

Čanković Milenko 24 June 2020 (has links)
<p>Ishemijska bolest srca najče&scaron;će nastaje kao posledica razvoja aterosklerotskih promena na koronarnim krvnim sudovima koji dovode do suženja lumena i posledičnog pada protoka arterijske krvi u području vaskularizacije. Akutni oblik koronarne bolesti koji zahteva hitnu primenu reperfuzione terapije je ST elevirani infarkt miokarda. EKG ima veliki značaj u postavljanju dijagnoze ali i u proceni uspe&scaron;nosti same reperfuzije. &Scaron;irina QRS kompleksa jedan je od EKG parametara čija dinamika promena može ukazati na uspe&scaron;nost pPKI i veličinu infarktne zone. Evaluacija &scaron;irine QRS kompleksa kao prediktora veličine infarkta miokarda i reperfuzije nakon pPKI kod pacijenata sa STEMI. Ispitivanje je sprovedeno kao prospektivna, opservaciona klinička studija na Klinici za kardiologiju, Instituta za kardiovaskularne bolesti Vojvodine u periodu od januara 2016. do decembra 2018. godine. U isptivanje je uključeno 200 pacijenata sa STEMI kod kojih je urađena pPKI. Na osnovu dužine trajanja tegoba formirane su dve grupe od po 100 pacijenata. Grupa A kod kojih je totalno ishemijsko vreme bilo &lt;6h i grupa B kod kojih je totalno ishemijsko vreme između 6 i 12h. . Sprovedeno je EKG praćenje radi procene &scaron;irine QRS kompleksa intrahospitalno (pre procedure, odmah nakon pPKI kao i posle 1h i 72h) i na dve vizite ambulantno tokom &scaron;estomesečnog praćenja (nakon mesec dana i &scaron;est meseci). Ehokardiografija je urađena kod svih pacijenata intrahospitalno i na &scaron;estomesečnom ambulantnom pregledu. &Scaron;irine QRS kompleksa su korelirane sa rezultatima interventne procedure procenjene TIMI protokom i TMPG, dinamikom kardiospecifičnih enzima i ehokardiografskim nalazima. U istraživanje je uključeno 71% mu&scaron;karaca i 29% žena, prosečna starost uzorka iznosila je 60.6&plusmn;11.39. Dužina trajanja tegoba značajno se razlikovala između grupa. U grupi A tegobe su trajale prosečno 120 minuta (90-180), dok su u grupi B trajale 420 minuta (360-600) (p&lt;0.0005). DTB nije se značajno razlikovao, 42 minuta (31-54.5) u odnosu na 40.5 minuta (34.5-55) (p=0.818). Prosečna &scaron;irina QRS kompeksa na EKG-u pre pPKI nije se značajno razlikovala između grupa, 100 msec (90-110) u odnosu na 100 msec (93-110) (p=0.308). Nakon reperfuzije uočena je značajna razlika u &scaron;irini QRS kompleksa između grupa na svim intrahospitalnim kao i EKG-ima načinjenim tokom perioda praćenja. QRS kompleks je &scaron;iri kod pacijenata iz grupe B (p&lt;0.0005). Pacijenti iz grupe A koji su imali prohodnu infarktnu arteriju sa TIMI 3 protokom pre implantacije stenta imali su značajno uži QRS kompleks na incijilanom EKG-u u odnosu na pacijente kod kojih je IRA bila sub/okludirana sa TIMI protokom &le;2 (p=0.001). U grupi B prohodna infarktna arterija sa TIMI 3 protokom nije značajno uticala na &scaron;irinu QRS kompleksa na inicijalnom EKG-u (p=0.144). Na EKG-ima nakon procedure QRS kompleks bio je značajno &scaron;iri kod pacijenata kod kojih je TIMI protok &le;2, ali samo za grupu pacijenata koja se javila unutar 6h od početka tegoba (p=0.001). QRS kompleks kod pacijenata koji su se javili nakon 6h od početka tegoba jeste bio uži, ali bez statistički značajne razlike (p=0.336). Pearsonovim testom registrovano je postojanje negativne korelacije &scaron;irine QRS kompleksa i istisne frakcije leve komore, ali i pozitivne korelacije sa WMSI i indeksiranim end sistolnim i end dijastolnim volumenom. ROC analizom pokazano je da ukoliko je QRS kompleks &scaron;iri od 89 msec nakon mesec dana, 8.5 puta je veći rizik od snižene EF na &scaron;estomesečnoj kontroli (p&lt;0.0005, AUC=0.808, cut-off=89msec.). ROC analiza pokazala je i da ukoliko je QRS kompleks &scaron;iri od 99msec 1h nakon procedure, 5 puta je veći rizik od pojave MACE (p&lt;0.0005, AUC=0.744, cut-off=99msec). Izvedena su dva matematička modela zasnovana na &scaron;irini QRS kompleksa koja vr&scaron;e predikciju snižene EF i pojave MACE tokom perioda praćenja. &Scaron;irina QRS kompleksa je pokazatelj reperfuzije kod pacijenata sa STEMI kod kojih se načini revaskularizacija unutar 6h od nastanka tegoba. &Scaron;irina QRS kompleksa mesec dana nakon STEMI predstavlja nezavisni prediktor snižene EF. Pro&scaron;irenje preko 89msec 8.5 povećava rizik od snižene EF. &Scaron;irina QRS kompleksa jedan sat nakon pPKI predstavlja nezavisni prediktor za MACE. Pro&scaron;irenje preko 99msec 5 puta povećava rizik od neželjenog kardiolo&scaron;kog događaja. Izvedena su dva matematička modela koja koriste &scaron;irinu QRS kompleksa i sa visokom precizno&scaron;ću vr&scaron;e predikciju MACE-a, odnosno snižene EF nakon &scaron;est meseci.&nbsp;</p> / <p>Ischemic heart disease most commonly occurs as a result of the atherosclerotic changes in the coronary vessels that lead to the narrowing of the lumen and consequent fall in arterial blood flow in the vascularization area. An acute form of coronary artery disease requiring immediate reperfusion therapy is ST-elevation myocardial infarction. The ECG is of great importance not only in making the diagnosis but also in evaluating the success of the reperfusion itself. The duration of the QRS complex is one of the ECG parameters whose change in dynamics can indicate the success of pPCI as well as the size of the infarct zone. Evaluation of the width of the QRS complex as a predictor of myocardial infarction size and reperfusion after pPCI in patients with STEMI. The study was conducted as a prospective, observational clinical study at the Cardiology Clinic of the Institute of Cardiovascular Diseases of Vojvodina between January 2016 and December 2018. The study included 200 patients with STEMI in whom pPCI was performed. Based on the length of discomforts two groups with 100 patients were formed. Group A had a total ischemic time &lt;6h and the total ischemic time in group B was between 6-12h. To assess the duration of the QRS complex, the ECG monitoring was performed intrahospital (before the procedure, immediately after pPCI as well as 1h and 72h after the procedure) and on two outpatient visits during the six-month follow-up period (after one month and six months). Echocardiography was performed in all patients intrahospital and at a six-month outpatient visit. The duration of the QRS complex correlated with the results of the interventional procedure that was evaluated by the TIMI flow and TMPG, the dynamics of cardiospecific enzymes and echocardiography findings. The survey included 71% of men and 29% of women with an average age of 60.6 &plusmn; 11.39. The duration of the discomforts varied significantly between the groups. In group A the discomforts lasted 120 minutes in an average (90-180), while they lasted 420 minutes in group B (360-600) (p &lt;0.0005). DTB did not differ significantly, 42 minutes (31-54.5) versus 40.5 minutes (34.5-55) (p = 0.818). The average duration of the QRS complex on the ECG before pPCI did not differ significantly between the groups, 100 msec (90-110) versus 100 msec (93-110) (p = 0.308). After the reperfusion, a significant difference in the duration of the QRS complex was observed between the groups at all intrahospital ECGs and the ECGs performed during the follow-up period. The QRS complex was broader in group B patients (p &lt;0.0005). Group A patients who had a patent infarct artery with TIMI 3 flow before the stent implantation had a significantly narrower QRS complex on the initial ECG compared to the patients whose IRA was sub / occluded with TIMI flow &le;2 (p = 0.001). In group B, the patent infarct artery with TIMI 3 flow did not significantly affect the duration of the QRS complex at the initial ECG. (p = 0.144). At the post-procedural ECGs the QRS complex was significantly broader in patients with TIMI flow &le;2, but only in the group of patients who arrived within 6 h from the onset of discomforts (p = 0.001). The QRS complex in patients who arrived 6 h after the onset of discomforts was narrower but without statistically significant difference (p = 0.336). The Pearson test registered the existence of a negative correlation of the QRS complex width and the left ventricular ejection fraction, but also a positive correlation with the WMSI and index end-systolic and end-diastolic volumes. The ROC analysis showed that if the QRS complex was wider than 89 msec after one month, there was an 8.5 times higher risk of decreased EF at the six-month control examination (p &lt;0.0005, AUC = 0.808, cut-off = 89msec.). The ROC analysis also showed that if the QRS complex was wider than 99msec 1h after the procedure, there was a 5 times higher risk of MACE (p &lt;0.0005, AUC = 0.744, cut-off = 99msec). Two mathematical models based on the width of the QRS complex were derived that predicted the lowered EF and the occurrence of MACE during the monitored period. The width of the QRS complex is an indicator of reperfusion in patients with STEMI who undergo revascularization within 6 hours from the onset of discomforts. The width of the QRS complex one month after STEMI is an independent predictor of decreased EF. Broadening over 89msec increases the risk of lowered EF for 8.5 times. The width of the QRS complex one hour after pPCI represents an independent predictor of MACE. Broadening over 99msec increases the risk of an adverse cardiac event 5 times. Two mathematical models have derived that use the width of the QRS complex and predict MACE with high precision as well as reduced EF after six months.</p>

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