| 1. |
- Boles, Usama, 1974-
(författare)
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Insight into coronary artery ectasia
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background:Coronary artery ectasia (CAE) is defined as a diffuse dilatation of the epicardial coronary arteries exceeding 1.5 folds the diameter of the normal adjacent arterial segment and/ or the remaining non-dilated part of the same artery. (1) The incidence of CAE has been variably reported between different nations and ranges between 1.4 -10 % (2-5). This wide range of variability is related to many factors including diverse definition of CAE, geographical distribution, association with other conditions (i.e. inflammatory, congenital or atherosclerosis) hence the existent uncertainty about disease burden and prevalence. (6) The main pathophysiology of CAE is initially understood to be part of atherosclerosis, (3) yet others reported the non-atherosclerotic nature of the disease. (2,7) The exact disease pathophysiology, prognosis and clinical outcome are not well studied; particularly the isolated, non-atherosclerotic, form of the disease has not been fully determined nor well identified. Methods:In paper 1, we examined the clinical presentation, prevalence and cardiovascular risk profile of the CAE patients in acute myocardial infarction (MI). We investigated the inflammatory response and short-term outcome in CAE patients of 3,321 acute consecutive MI patients who underwent primary PCI in two different centres in the UK (Royal Free Hospital, London and Norfolk, and Norwich University Hospital) between January 2009 and August 2012.In paper 2, we studied the personalised lipid profile and immune-inflammatory response in CAE patients from two different destinations (16 patients, mean age 64.9 ± 7.3 years, 6 female) Umea, Sweden and Letterkenny, Ireland. The lipidomic profile was compared with 26 control group (mean age 59.2 ± 6.6, 7 female) with normal coronary arteries.In paper 3, the plasma levels of 16 CAE (mean age 64.9 ± 7.3 years, 6 female) were compared with 69 age and gender matched (mean age 64.5 ± 8.7 years, 41 female) subjects with evidence of coronary artery disease and 140 controls with normal coronary arteries (mean age 58.6 ± 4.1 years, 81 female) in order to determine differences in inflammatory markers and cytokines, specific for CAE.In paper 4, we investigated long term follow up data of CAE patients without atherosclerotic burden. This represents follow up data of 66 patients with CAE, among 16,464 patients, who underwent diagnostic coronary angiography in Umea, Sweden and Letterkenny university Hospital, Ireland between 2003 and 2009. Of the 66 patients, long-term follow up (mean 11.3 ± 1.6 years) data was complete in 41 patients (age 66 ± 9 years), 12 Female. All hospital readmissions with Major Acute Cardiac Events (MACE) including mortality and morbidity and hospital readmissions for acute coronary syndrome (ACS) were compared with gender matched 41 controls. No subject had >20% coronary stenosis in any coronary branch. Results:Paper 1: The prevalence of CAE with acute MI was 2.7%. Apart from diabetes mellitus (DM) that was significantly less common in the CAE group (p=0.02), the other conventional cardiovascular risk factors were similar between ectatic and non-ectatic coronary arteries. The RCA and LCx were predominantly involved in patients with CAE (p=0.001 and 0.0001, respectively). CRP was higher (p=0.006) in CAE, but both WCC, neutrophil and neutrophil/lymphocyte ratio (N/L ratio) was lower (p = 0.002, 0.002 and 0.032). The short-term follow-up of 2 years showed no relationship between the inflammatory markers and MACE [(8/28, 28.6%) CAE vs. (13/60, 21.7%) without CAE, (p = 0.42)].Paper 2: We identified 65 different metabolites between CAE group and controls, 27 of them were identifiable using metabolomics library software (15 were fully identified and 12 were identified through the size of the side chains). Sixteen species of phosphatidylcholines (PC); and 11 sphyngomyelins (SM) species had significantly lower intensities in patients with CAE.Paper 3: Systemic levels of IFN-γ, TNF-α, IL-1β, IL-6 and IL-8 were significantly higher in the CAE group compared to the CAD group (p = 0.006, 0.001, 0.001, 0.046 and 0.009, respectively) and the control group (p = 0.032, 0.002, 0.001, 0.049 and 0.007 in the same order), while the levels of IL-2 and IL-4 were lower (P < 0.001 for both) compared to the CAD and the control group. No differences were detected in the systemic levels of cytokines IL-10, IL-12P “subunits IL-12 and IL-23”, and IL-13 between the two patient groupsPaper 4: While CAE patients were slightly older, they had longer follow up period (p<0.001) than controls. The overall mortality in the CAE group was higher (p<0.001) and similarly was CV mortality (p<0.03) compared with controls. MACE was similar in both groups (p=0.18). More patients smoked (p<0.001) and have family history for CAD (p<0.02) than controls but these variables were not different between survivals (36 patients) and non-survivors (5 patients). Females had more MACE than males (p<0.03). Finally, all non-survivors and 12/36 survivors had smoked and had dyslipidemia. Conclusion:Coronary artery ectasia, despite of common association with atherosclerosis, had a lower disease prevalence and dysregulated lipid metabolic profile than atherosclerosis. The pro-systemic inflammatory response in CAE is also different from atherosclerosis with different Cytokines milieu. In the context of CAE with acute coronary syndrome with obstructive atherosclerotic CAD, the management options should follow the standard guidelines for revascularization. CAE may lead to exaggerated inflammatory response in acute settings but the short-term outcome is similar to non-ectatic obstructive CAD. However, long term follow up data showed higher mortalities and hospital readmissions, yet no difference in MACE.
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| 2. |
- Calcutteea, Avin, 1978-
(författare)
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New insights in the assessment of right ventricular function : an echocardiographic study
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The right ventricle (RV) is multi-compartmental in orientation with a complex structural geometry. However, assessment of this part of the heart has remained an elusive clinical challenge. As a matter of fact, its importance has been underestimated in the past, especially its role as a determinant of cardiac symptoms, exercise capacity in chronic heart failure and survival in patients with valvular disease of the left heart. Evidence also exists that pulmonary hypertension (PH) affects primarily the right ventricular function. On the other hand, previous literature suggested that severe aortic stenosis (AS) affects left ventricular (LV) structure and function which partially recover after aortic valve replacement (AVR). However, the impact of that on RV global and segmental function remains undetermined. Objectives: We sought to gain more insight into the RV physiology using 3D technology, Speckle tracking as well as already applicable echocardiographic measures. Our first aim was to assess the normal differential function of the RV inflow tract (IT), apical and outflow tract (OT) compartments, also their interrelations and the response to pulmonary hypertension. We also investigated the extent of RV dysfunction in severe AS and its response to AVR. Lastly, we studied the extent of global and regional right ventricular dysfunction in patients with pulmonary hypertension of different aetiologies and normal LV function.Methods: The studies were performed on three different groups; (1) left sided heart failure with (Group 1) and without (Group 2) secondary pulmonary hypertension, (2) severe aortic stenosis and six months post AVR and (3) pulmonary hypertension of different aetiologies and normal left ventricular function. We used 3D, speckle tracking echocardiography and conventionally available Doppler echocardiographic transthoracic techniques including M-mode, 2D and myocardial tissue Doppler. All patients’ measurements were compared with healthy subjects (controls). Statistics were performed using a commercially available SPSS software.Results:1- Our RV 3D tripartite model was validated with 2D measures and eventually showed strong correlations between RV inflow diameter (2D) and end diastolic volume (3D) (r=0.69, p<0.001) and between tricuspid annular systolic excursion (TAPSE) and RV ejection fraction (3D) (r=0.71, p<0.001). In patients (group 1 & 2) we found that the apical ejection fraction (EF) was less than the inflow and outflow (controls: p<0.01 & p<0.01, Group 1: p<0.05 & p<0.01 and Group 2: p<0.05 & p<0.01, respectively). Ejection fraction (EF) was reduced in both patient groups (p<0.05 for all compartments). Whilst in controls, the inflow compartment reached the minimum volume 20 ms before the outflow and apex, in Group 2 it was virtually simultaneous. Both patient groups showed prolonged isovolumic contraction (IVC) and relaxation (IVR) times (p<0.05 for all). Also, in controls, the outflow tract was the only compartment where the rate of volume fall correlated with the time to peak RV ejection (r = 0.62, p = 0.03). In Group 1, this relationship was lost and became with the inflow compartment (r = 0.61, p = 0.01). In Group 2, the highest correlation was with the apex (r=0.60, p<0.05), but not with the outflow tract.2- In patients with severe aortic stenosis, time to peak RV ejection correlated with the basal cavity segment (r = 0.72, p<0.001) but not with the RVOT. The same pattern of disturbance remained after 6 months of AVR (r = 0.71, p<0.001). In contrast to the pre-operative and post-operative patients, time to RV peak ejection correlated with the time to peak outflow tract strain rate (r = 0.7, p<0.001), but not with basal cavity function. Finally in patients, RVOT strain rate (SR) did not change after AVR but basal cavity SR fell (p=0.04).3- In patients with pulmonary hypertension of different aetiologies and normal LV function, RV inflow and outflow tracts were dilated (p<0.001 for both). Furthermore, TAPSE (p<0.001), inflow velocities (p<0.001), basal and mid-cavity strain rate (SR) and longitudinal displacement (p<0.001 for all) were all reduced. The time to peak systolic SR at basal, mid-cavity (p<0.001 for both) and RVOT (p=0.007) was short as was that to peak displacement (p<0.001 for all). The time to peak pulmonary ejection correlated with time to peak SR at RVOT (r=0.7, p<0.001) in controls, but with that of the mid cavity in patients (r=0.71, p<0.001). Finally, pulmonary ejection acceleration (PAc) was faster (p=0.001) and RV filling time shorter in patients (p=0.03) with respect to controls.Conclusion: RV has distinct features for the inflow, apical and outflow tract compartments, with different extent of contribution to the overall systolic function. In PH, RV becomes one dyssynchronous compartment which itself may have perpetual effect on overall cardiac dysfunction. In addition, critical aortic stenosis results in RV configuration changes with the inflow tract, rather than outflow tract, determining peak ejection. This pattern of disturbance remains six month after valve replacement, which confirms that once RV physiology is disturbed it does not fully recover. The findings of this study suggest an organised RV remodelling which might explain the known limited exercise capacity in such patients. Furthermore, in patients with PH of different aetiologies and normal LV function, there is a similar pattern of RV disturbance. Therefore, we can conclude that early identification of such changes might help in identifying patients who need more aggressive therapy early on in the disease process.
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| 3. |
- Charisopoulou, Dafni, 1972-
(författare)
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Myocardial electromechanical function in long QT syndrome
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- AIM: The aim of this thesis is to assess, in LQTS and according to genotype, the myocardial electromechanical (EM) function response to exercise, its relation to symptoms and its response to b-blocker therapy. To achieve this aim, we conducted 4 studies with the following specific objectives: i. To study the ventricular repolarization (QTc interval) behaviour during stress and its potential haemodynamic effects, as reflected in left ventricular filling and stroke volume response to exercise.ii. To access the exercise response of electromechanical coupling, expressed by the electromechnical window (EMW), and its relation to symptoms.iii. To access for potential mechanical disturbances during stress by studying the myocardial contraction response to exercise, its effects on myocardial diastolic function and their relation to co-existent ventricular repolarization disturbances.iv. To investigate the myocardial behaviour during early relaxation an most particularly the longitudinal apico-basal relaxation sequence, its synamic response to exercise and any potentia contribution to the development of symptoms.v. To investigate the effect of b-blocker therapy on the above electromechanical parameters at rest and during exercise. METHODS: Forty seven (age 45±15yrs, 25 female, 20 symptomatic) LQTS mutation carriers and 35 healthy individuals (matched for age and sex) underwent an exercise test (Bruce protocol). ECG and doppler and speckle-tracking echo parameters were recorded at rest, peak exercise and recovery. RESULTS: We found that abnormal ventricular repolarization in LQTS carriers was related to marked LV mechanical dispersion and to abnormally reversed LV end-systolic electromechanical relationship and longitudinal early relaxation sequence. These phenomena worsened at peak exercise, especially in LQT1 carriers, and were related to impaired LV daistolic function and attenuated stroke volume response to exercise. Such abnormal electromechanical responses to exercise were more pronounces in LQTS subjects with previous adverse cardiac events and could better identigy these subjects than QTc interval alone. These disturbances were also less pronounced in LQTS carriers treated with b-blockers. CONCLUSION: Incorporating stress-echocardiograhic evaluation of electromechanical parameters in the routine assessment of LQTS individuals may help better stratification, symptom interpretation and management.
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| 4. |
- Holmgren, Anders, 1956-
(författare)
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Metabolic risk markers and relative survival in patients with aortic stenosis requiring surgery
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Aortic stenosis (AS) is the most common valve disorder requiring surgery in developed countries. The etiology of AS is only partly known. Identification of new biomarkers in prospective studies could lead to novel insights in the etiology of AS, and possibly lead to improved clinical management. Long term observed survival after aortic valve surgery has improved over the last decades despite an ageing population presenting with more comorbidities. Whether this is reflected in improved relative survival is not known. We evaluated if biomarkers associated prospectively with AS requiring surgery, and if these associations differed between genders, time to surgery and the presence of coronary artery disease (CAD). We also assessed long term observed and relative survival after aortic valve surgery with and without concomitant coronary artery by-pass surgery (CABG).Methods and results: Study I: We prospectively studied the impact of lipoprotein (a)(Lp[a]) and apolipoproteins (Apo) in subgroups of AS. During a 20-year period, 336 patients with prior participation in large population-based surveys in northern Sweden were operated due to AS plus CABG when indicated. For each case two referents were matched. Data from the baseline survey were collected and included data on cardiovascular risk factors, health history, measurements of anthropometry, blood pressure, blood glucose and blood lipid levels were retrieved. Data from pre- and perioperative assessments were also collected. The presence of CAD was determined from the coronary angiogram. Elevated levels of Lp(a) and an elevated Apo B/Apo A 1 ratio were independently associated with future surgery for AS, but only in patients with concomitant CAD (OR 1.29, 95 % CI 1.07-1.55 and 1.43, 95 % CI 1.16-1.76 respectively). Study II: The same patient cohort as in study I was used. A panel of 92 cardiovascular candidate proteins were analysed with the multiplex proximity extension assay in samples obtained at baseline. Six circulating proteins (growth differentiation factor 15[GDF-15], galectin-4, von Willebrand factor [vWF], interleukin 17 receptor A, transferrin receptor protein 1, and proprotein convertase subtilisin/kexin type 9, [PCSK9]) were associated with future surgery for AS in patients with concurrent CAD (ORs ranged from 1.25 to 1.37 per SD increase in the protein signal). In the validation study with 106 additional cases, the association of all but one, (interleukin 17 receptor A), of these proteins were replicated in patients with AS and concurrent CAD but not in those without concurrent CAD. Study III: In the same patient cohort as in study I and II we evaluated if troponin T (TnT) and C-reactive protein (CRP) associated prospectively with future surgery for AS. TnT was independently associated with surgery for AS in patients both with (OR 1.22, 95 % CI 1.02-1.46) and without concomitant CAD (1.39, 95% CI 1.05-1.84). CRP was not associated with surgery for AS (OR 1.06, 95 % CI 0.92-1.23). Study IV: 4970 patients between 2005 and 2016 from three Swedish heart surgery centres, undergoing aortic valve replacement (AVR) due to either AS or aortic regurgitation in conjunction with CABG when indicated, were followed up. All-cause mortality, as well as both observed and relative survival, was analysed with focus on age, sex, type of valve prosthesis and the impact of concomitant CABG. Median follow-up was 4.7 years (2.3-7.6). 30-day mortality was 2.3 %. Long-term survival with 30-day mortality excluded was 96.6 %, 82.7 %, 57.6 % after 1, 5 and 10 years respectively. Relative survival rates (adjusting for the background mortality in the general Swedish population based on age, sex and year) were 99.6 %, 99.5 % and 90.6 % after 1, 5 and 10 years respectively. Age had a negative influence on observed survival (p<0.001) but was associated with better relative survival (relative mortality rate [RMR] 0.74, 95 % CI 0.71 - 0.77). Women had a lower observed mortality than men (p<0.001) but a lower relative survival (RMR 1.17, 95 % CI 1.02-1.35). Combined surgery (AVR+CABG) was not significantly associated with higher mortality (p=0.43) in a multivariable adjusted analysis. The presence of bicuspid morphology was associated with lower observed mortality compared with tricuspid valve, and a relative survival matching that in the general population.Conclusion: I. Plasma levels of Lp(a) and the Apo B/Apo A 1 ratio were independently associated with future surgery for AS but only in patients with concomitant CAD. This finding suggests that patients with AS have different phenotypes and may open a new avenue of research on targeted risk factor interventions in this population. II. Five circulating proteins – GDF-15, galectin-4, vWF, transferrin receptor protein 1, and PCSK9 – were associated with the need for aortic valve surgery several years later. The role of these proteins should be investigated in future studies. III. Elevated plasma levels of TnT were independently associated with future surgery for AS, irrespective of the presence of concomitant CAD, which could indicate that the myocardium is subject to mechanical stress already in the subclinical stage of AS. This may be used as a clinical tool for identification of patients with subclinical AS who could benefit from early intervention. Elevated CRP levels did not associate with future AVR. IV. Relative survival following AVR was particularly good in the elderly matching that in the general population underlining the benefits of aortic valve surgery in properly selected patients. Women had decreased relative survival compared to men. This should be explored in future studies. Adding CABG to an AVR procedure was not associated with increased risk. Bicuspid valve morphology was associated with lower observed mortality compared with tricuspid valve morphology, and with a relative survival matching that of the general population.
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| 5. |
- Ibrahimi, Pranvera, 1986-
(författare)
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Patterns of non-invasive imaging of carotid atherosclerosis
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerosis is an inflammatory disease that can be generalized, affecting more than one arterial bed simultaneously, or localized, manifested in one system. Ultrasound based measurements of plaque textural features, such as low grey scale median (GSM), echolucent (hypoechoic) plaque types and juxtaluminal black (hypoechoic) area (JBA) are manifestation of potentially unstable lesions. Conventional carotid IMT (intima media thickness) and the recently introduced IM-GSM (echogenicity of the intima media complex) are important measures of subclinical atherosclerosis and are used to predict future ischemic events.The aims of this thesis were to study, in detail, the systemic nature of atherosclerosis by evaluating the carotid disease burden contralateral to symptomatic arteries, determining the relationship between proximal (subclinical atherosclerosis) and distal segments (well established disease) of the same artery and comparing local plaque features with systemic burden of atherosclerosis disease. In addition, the effect of statins on carotid plaque echogenicity was evaluated in a systematic review and meta-analysis.Methods:We have measured ultrasound-based textural carotid plaque features (GSM, JBA, entropy, coarseness), surface morphology, as well as IMT and IM-GSM. An in-house custom developed research software package was used for plaque feature extraction. For the meta-analysis we used Comprehensive Meta-Analysis version 3 software.Results:Study 1. In 39 patients, the carotid plaques contralateral to symptomatic arteries had similar morphological and textural features to those in the symptomatic arteries and are more vulnerable than those in asymptomatic arteries; more often mildly or markedly irregular with more vulnerable textural plaque features (lower GSM and larger JBA).Study 2. In 87 asymptomatic patients, an increased IMT in CCA correlated with plaque irregularities in the bifurcation and ICA while IM-GSM was closely related to plaque echogenicity (GSM), and other textural plaque features.Study 3. In the same cohort in study 2, patients with previous disease in the coronary arteries had higher IMT and lower IM-GSM and those with prior stroke had lower IM-GSM. Neither IMT nor IM-GSM was different between patients with and without previous lower extremity disease. IM-GSM decreases significantly with increasing number of arterial territories p<0.001 (asymptomatic vs symptoms in one vs multiple arterial systems) but conventional IMT was not different between groups p=0.49.Study 4. In a meta-analysis of 9/580 identified studies including 566 patients with 7.2 months follow-up, a consistent increase in the carotid plaques echogenicity after statin therapy, was reported. The perpetual (over 12 months) effects of which were shown in a meta-regression analysis to be related to changes in hsCRP.Conclusion: Symptomatic patients have similar plaque morphology and textural features of vulnerability in the contralateral carotid system, compared with asymptomatic ones. In the latter, measurements of proximal disease reflect distal pathology and the number of affected arteries. Finally, statin therapy and the drop of LDL cholesterol result in better plaque stability and optimum control of arterial inflammation, shown by arterial wall echogenicity and hsCRP changes, respectively.
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| 6. |
- Lisi, Matteo, 1982-
(författare)
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Insights into left atrial response to pressure and volume overload
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general purpose of this thesis is to establish the ability of Speckle Tracking Echocardiography (STE) in assessing left atrial (LA) response to pressure and volume overload respectively in aortic stenosis (AS) and mitral regurgitation (MR), and to evaluate its accuracy in predicting LA and right ventricular (RV) fibrosis in patients with end-stage heart failure (HF) undergoing heart transplantation (HTx).I demonstrated that assessment of left ventricular (LV) long axis systolic velocity and amplitude of excursion is more sensitive than simple determination of ejection fraction (EF) for revealing the beneficial impact of MR surgery on overall LV systolic performance.Severe symptomatic AS is associated with LA enlargement and compromised mechanical function with a high incidence of peri-operative atrial fibrillation (AF). Valve replacement reverses these abnormalities and regains normal atrial function, a behaviour which is directly related to the severity of pre-operative LV outflow tract obstruction. Early identification of LA size and function disturbances, as shown by myocardial strain measurements might contribute to better patient’s recruitment for a safe valve replacement.In late stage HF patients, the right ventricle is enlarged, with reduced systolic function due to significant myocardial fibrosis. RV free wall myocardial deformation is the most accurate function measure that correlates with the extent of RV myocardial fibrosis and functional capacity.In patients with preserved EF, severe MR masks LV and LA myocardial dysfunction and correlates with symptoms and post-operative cavity function instability. Three months after MVR, the underlying myocardial disturbances are unmasked suggesting that most pre-operative measurements are subject to loading conditions. Finally LA volume and PALS remain the main predictors of post-operative AF, thus should be used for stratifying surgical risk.STE has been shown to accurately determine the severity of impairment of LA myocardial function shown by suppressed PALS which was the strongest predictor of the presence and extent of fibrosis, over and above other structure and function parameters. These findings may assist in better stratifying patients with end stage HF and identifying particularly those requiring HTx.
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| 7. |
- Nicoll, Rachel, 1955-
(författare)
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Insights into the relationship between coronary calcification and atherosclerosis risk factors
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction Coronary artery disease (CAD) is the most common cause of death in Europe and North America and early detection of atherosclerosis is a clinical priority. Diagnosis of CAD remains conventional angiography, although recent technology has introduced non-invasive imaging of coronary arteries using computed tomographic coronary angiography (CTCA), which enables the detection and quantification of coronary artery calcification (CAC). CAC forms within the arterial wall and is usually found in or adjacent to atherosclerotic plaques and is consequently known as sub-clinical atherosclerosis. The conventional cardiovascular (CV) risk factors used to quantify the estimated 10-year coronary event risk comprise dyslipidaemia, hypertension, diabetes mellitus, obesity, smoking and family history of CAD. Nevertheless, their relationship with significant (>50%) stenosis, their interaction with the CAC score and their predictive ability for CAC presence and extent has not been fully determined in symptomatic patients. Methods For Papers 1-4 we took patients from the Euro-CCAD cohort, an international study established in 2009 in Umeå, Sweden. The study data gave us the CAC score and the CV risk factor profile in 6309 patients, together with angiography results for a reduced cohort of 5515 patients. In Papers 1 and 2 we assessed the risk factors for significant stenosis, including CAC as a risk factor. Paper 2 carried out this analysis by geographical region: Europe vs USA and northern vs southern Europe. Paper 3 investigated the CV risk factors for CAC presence, stratified by age and gender, while Paper 4 assessed the CV risk factors for CAC extent, stratified by gender. In paper 5 we carried out a systematic review and meta-analysis of all studies of the risk factor predictors of CAC presence, extent and progression in symptomatic patients. From a total of 884 studies, we identified 10 which fitted our inclusion criteria, providing us with a total of 15,769 symptomatic patients. All 10 were entered in the systematic review and 7 were also eligible for the meta-analysis. ResultsPaper 1: Among risk factors alone, the most powerful predictors of significant coronary stenosis were male gender followed by diabetes, smoking, hypercholesterolaemia, hypertension, family history of CAD and age; only obesity was not predictive. When including the log transformed CAC score as a risk factor, this proved the most powerful predictor of >50% stenosis, but hypercholesterolaemia and hypertension lost their predictive ability. The conventional risk factors alone were 70% accurate in predicting significant stenosis, the log transformed CAC score alone was 82% accurate but the combination was 84% accurate and improved both sensitivity and specificity. Paper 2: Despite some striking differences in profiles between Europe and the USA, the most important risk factors for >50% stenosis in both groups were male gender followed by diabetes. When the log CAC score was included as a risk factor, it became by far the most important predictor of >50% stenosis in both continents, followed by male gender. In the northern vs southern Europe comparison the result was similar, with the log CAC score being the most important predictor of >50% stenosis in both regions, followed by male gender. Paper 3: Independent predictors of CAC presence in males and females were age, dyslipidaemia, hypertension, diabetes and smoking, with the addition of family history of CAD in males; obesity was not predictive in either gender. The most important predictors of CAC presence in males were dyslipidaemia and diabetes, while among females the most important predictors of CAC presence were diabetes followed by smoking. When analysed by age groups, in both males and females aged <70 years, diabetes, hypertension and dyslipidaemia were predictive, with diabetes being the strongest; in females aged <70 years, smoking was also predictive. Among those aged ≥70 years, the results are completely different, with only dyslipidaemia being predictive in males but smoking and diabetes were predictive in females. Paper 4: In the total cohort, age, male gender, diabetes, obesity, family history of CAD and number of risk factors predicted an increasing CAC score, with the most important being male gender and diabetes. In males, hypertension and dyslipidaemia were also predictive, although diabetes was the most important predictor. Diabetes was similarly the most important risk factor in females, followed by age and number of risk factors. Among patients with CAC, hypertension, dyslipidaemia and diabetes predicted CAC extent in both males and females, with diabetes being the strongest predictor in males followed by dyslipidaemia, while diabetes was also the strongest predictor in females, followed by hypertension. Quantile regression confirmed the consistent predictive ability of diabetes. Paper 5: In the systematic review, age was strongly predictive of both CAC presence and extent but not of CAC progression. The results for CAC presence were overwhelmed by data from one study of almost 10,000 patients, which found that white ethnicity, diabetes, hypertension and obesity were predictive of CAC presence but not male gender, dyslipidaemia, family history or smoking. With respect to CAC extent, only male gender and hypertension were clearly predictive, while in the one study of CAC progression, only diabetes and hypertension were predictive. In the meta-analysis, hypertension followed by male gender, diabetes and age were predictive of CAC presence, while for CAC extent mild-moderate CAC was predicted by hypertension alone, whereas severe CAC was predicted by hypertension followed by diabetes. ConclusionOur investigation of the Euro-CCAD cohort showed that the CAC score is far more predictive of significant stenosis than risk factors alone, followed by male gender and diabetes, and there was little benefit to risk factor assessment over and above the CAC score for >50% stenosis prediction. Regional variations made little difference to this result. Independent predictors of CAC presence were dyslipidaemia and diabetes in males and diabetes followed by smoking in females. The risk factor predictors alter at age 70. The most important risk factor predictors of CAC extent were male gender and diabetes; when analysed by gender, diabetes was the most important in both males and females. Our studies have consistently shown the strong predictive ability of male gender in the total cohort and diabetes in males and females and this is reflected in the meta-analysis, which also found hypertension to be independently predictive. Interestingly, dyslipidaemia does not appear to be a strong risk factor.
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| 8. |
- Ramzy Guirguis, Ihab, 1963-
(författare)
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Insights into the effect of myocardial revascularisation on electrical and mechanical cardiac function
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Acute coronary syndrome is known for its effect on cardiac function and can lead to impaired segmental and even global myocardial function. Evidence exists that myocardial revascularisation whether pharmacological, interventional or surgical results in improvement of systolic and diastolic left ventricular (LV) function, particularly that of the long axis which represents the sub-endocardial function, known as the most sensitive layer to ischaemia. Objective: We sought to gain more insight into the early effect of pharmacological and interventional myocardial revascularisation on various aspects of cardiac function including endocrine, electrical, segmental, twist, right ventricular (RV) and left atrial (LA) function. In particular, we aimed to assess the response of ventricular electromechanical function to thrombolysis and its relationship with peptides levels. We also investigated the behaviour of RV function in the setting of LV inferior myocardial infarction (IMI) during the acute insult and early recovery. In addition, we aimed to assess in detail LA electrical and mechanical function in such patients. Finally, we studied the early effect of surgical revascularisation on the LV mechanics using the recent novel of speckle tracking echocardiography technology to assess rotation, twist and torsion and the strain deformation parameters as a tool of identifying global ventricular function. Methods: We used conventionally Doppler echocardiographic transthoracic techniques including M-mode, 2-Dimentional, myocardial tissue Doppler, and speckle tracking techniques. Commercially available SPSS as a software was used for statistical analysis. Results: 1-The elevated peptide levels at 7 days post-myocardial infarction correlated with the reduced mechanical activity of the adjacent non-infarcted segment thus making natriuretic peptides related to failure of compensatory hyperdynamic activity of the non-infarcted area rather than the injured myocardial segments. 2-RV segmental and global functions were impaired in acute IMI, and recovered in 87% of patients following thrombolysis. In the absence of clear evidence for RV infarction the disturbances in the remaining 13% may represent stunned myocardium with its known delayed recovery. 3-LA electromechanical function was impaired in acute inferior STEMI and improved after thrombolysis. The partial functional recovery suggests either reversible ischaemic pathology or a response to a non-compliant LV segment. The residual LA electromechanical and pump dysfunction suggest intrinsic pathology, likely to be ischaemic in origin. 4-LV function was maintained in a group of patients with multivessel coronary artery disease who underwent coronary artery bypass graft (CABG) surgery. Surgical myocardial revascularisation did not result in any early detectable change in the three functional components of the myocardium, including twist and torsion, as opposite to conventional percutaneous coronary intervention (PCI). Conclusion: The studied different materials in this thesis provide significant knowledge on various aspects of acute ischaemic cardiac pathology and early effect of revascularisation. The use of non-invasive imaging, particularly echocardiography with its different modalities, in studying such patients should offer immediate thorough bed-side assessment and assist in offering optimum management.
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| 9. |
- Shenouda, Rafik B., 1971-
(författare)
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Insight into Coro-Carotid atherosclerotic disease in patients with acute coronary syndrome
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: the arterial tree branches in different parts of human body are sharing the histological and physiological features. Atherosclerosis is a systemic arterial disease, hence is expected to affect to affect more than one arterial system with similar pathologic manifestations.Aim: the aim of this thesis is to highlight the relationship between the two arterial systems involved in common acute ischemia, the carotid and coronary arteries, and to focus on the diagnostic tools that could be of help in estabilishing accurate diagnosis.Methods: we conducted five studies, the first three looked into the acute coronary syndrome and the different echocardiographic imaging modalities, including 2-Dimentional wall motion abnormalities, M-mode measurments, and myocardial deformation parameters measurment (Strain and Strain rate) in identifying the culprit coronary lesion (study 1), early recovery of left ventricular function after acute coronary syndrome (study 2) and the third study is a comparison between conventional 2-D dobutamine stress echocardiography and dobutamine stress echocardiography analysis using speckle tracking technique. The fourth and fifth studies are analyzing the relationship between the carotid calcifications measured by conventional computed tomogaphy based on Agatston calcium scoring and that of the coronary arteries (study 4) and the fifth study looked at the carotid and coronary atherosclerosis manifestation in a systematic review and mata-analysis.Results: Left ventricular myocardial strain rate was the most sensetive peridictor of the culprit artery lesion in the setting of acute coronary syndrome, measurment of deformation parameters are more sensetive than those of conventional echo in detecting early recovery of left ventricular function after acute coronary syndrome. Myocardial deformation parameters messured by speckle traching technique during dobutamine stress echo cardiography are more senstive than convetional 2-D measurments in detecting the stenosed arteries. Coronary calcifications is 10 times higher than carotid calcifications in acute coronary syndrome patients. There was moderate relationship between Carotid intima media thickness and the degree of stenosis of the coronary arteries.Conclusions: resting echocardiographic measurments are accurate in predicting the culprit coronary artery lesions in patients presenting with acute coronary syndrome. myocardial deformation measurments are the most accurate parameter that identify culprit lesion and left venticular segmental recovery and also are more sensetive than conventioal 2-D dobutamine stress echo in redicting stenosed coronaries in patients post acute coronary syndrome and with low ejection fraction. atherosclerosis parameters of the carotid arteriescorrelates with those of the coronary circulation, despite different phenotypic presentation. this finding highlights the importance of measuring the carotid intima media thickness in suspected high risk patients with acute coronary syndrome.
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- Tossavainen, Erik, 1977-
(författare)
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In the hands of ohm : hemodynamic aspects in pulmonary hypertension
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Congestive heart failure (CHF) is one of the most challenging diseases in terms of health care demand and mortality, in the western world. Despite major breakthroughs in the fields of diagnosis and treatment over the three last decades, the management of CHF still remains challenging.CHF is defined as inability of the heart to supply sufficient blood flow to meet the needs of the body. This definition however, may be an oversimplification of a complex pathophysiological process since patients with overt CHF may have normal, or even supernormal cardiac output at the expense of increased filling pressures, which subsequently leads to the development of post capillary pulmonary hypertension (PH). In the presence of advanced CHF, clinical signs and symptoms are obvious at rest. However, the majority of affected individuals do not experience any discomfort at rest and may demonstrate normal findings when assessed. Small increases in systemic blood pressure and or venous return, caused by activity may result in severe elevation of filling pressures if left ventricular compliance is significantly decreased. This example highlights the need to perform cardiac investigations during stress to provoke symptoms. Increased pulmonary vascular resistance (PVR), commonly found in pre-capillary PH, is a condition that shares many symptoms with CHF, and is also associated with poor prognosis. Even though the disease is located within the lung vessels, it is highly important and challenging task differentiating pre- and post-capillary PH. Since treatment differs considerably and may be detrimental in case of misdiagnosis, additional sensitive and reliable screening methods are crucial to aid in differentiation.Methods: Out of the four studies included in this thesis, three were conducted solely at Norrland’s University Hospital, while patients in the third study were recruited and examined at Uppsala Akademiska Hospital. All included patients had idiopathic dyspnea and were admitted for right heart catheterization (RHC), which is gold standard with regards to hemodynamics. Echocardiographic examinations were performed simultaneously with RHC, except in the Uppsala study, wherein echocardiography were performed within 3 days to the RHC.Echo-Doppler derived pulmonary artery acceleration time (PAcT) is an easily assessed parameter, indicating elevated pulmonary artery systolic pressure (PASP) and pulmonary artery resistance (PVR). PAcT was tested as a screening method for identification and differentiation of pre and post- capillary PH in a cohort of 56 patients (study 1).The ability to calculate PVR non-invasively, using novel echocardiographic measurements, was made by replacing the invasive pressure and flow components that constitutes the foundation of the PVR = (mean pulmonary artery pressure – Pulmonary capillary wedge pressure (PCWP)) /cardiac output), with novel echocardiographic measurements. PVR = mPAP-Chemla – Left atrial strain rate during atrial systole (LASRa) / Cardiac Output-Echo (study 2).Invasively measured left ventricular filling pressure in response to passive leg lifting, and its ability to predict pathological increase in left ventricular filling pressures during supine bicycling, was tested in a population of 85 patients with normal left ventricular ejection fraction (LVEF) and suspicion of CHF based on NT-proBNP levels alone were investigated (Study 3).Finally, an evaluation of standard and novel Doppler echocardiographic parameters, potentially useful in identifying patients who may develop increased filling pressures during passive leg lifting (PLL), was carried out (study 4).Results:Study 1: PAcT correlated negatively with pulmonary artery systolic pressure (PASP) (r = -0.60, p < 0.001) and PVR (r = -0.57, p < 0.001). PAcT of <90 ms had a sensitivity of 84% and a specificity of 85% in identifying patients with PVR ≥ 3.0 WU. Regardless of normal or elevated left sided filling pressures, PAcT differed significantly in patients with normal, compared to those with elevated levels of, PVR (p < 0.01). A significant difference was also found on comparison of the PAcT/PASP ratio (p < 0.01), with a lower ratio among patients with PVR ≥ 3.0. WU.Study 2: We prospectively used Doppler and 2D echocardiography in 46 patients with sinus rhythm which revealed that left atrial strain rate during atrial systole (LASRa) had the highest significant positive correlation with PCWP (r2 = 0.65, P < 0.001). By adopting a linear line of best-fit, LASRa may therefore be substituted for PCWP. Subsequently, LASRa was substituted into the PVR equation. This novel echocardiographically derived PVR calculation, significantly correlated with RHC generated PVR values (r2 = 0.69, P < 0.001) and minor drift (+0.1WU) when assessed by Bland Altman analysis.Study 3: Only 22% (11/51) of patients with elevated NT-proBNP had PCWP above normal levels at rest. However, in response to PLL, 47% of patients developed elevated PCWP, and the majority of this 47% subsequently developed pathological pressure levels while performing supine cycling exercise. Thus, the likelihood of developing high LVFPs during exercise could be determined by PLL, with a sensitivity and specificity of 90%.Study 4: At rest, left atrial volume indexed to body mass index (BMI) (LAVI) and mitral deceleration time (DT) were independently related to PCWP during PLL. However, during PLL univariate regression analysis revealed LASRa (β = -0.77, P <0,001) and E/LVSRe (β = 0.47, P < 0,021) most related to PCWPPLL. Multiple regression analysis fortified LASRa and E/LVSRe as relevant independent parameters useful in the assessment of filling pressure during PLL.Conclusion: A PAcT < 90ms is strongly suggestive of increased PVR (>3.0 WU). Based on study 1, there is clear evidence suggesting that these findings apply irrespective of LVFPs. PAcT can potentially serve as a rapid screening tool for estimation of PVR, however, is not useful if the exact level of PVR is required. In this case, an established PVR calculation method is preferred, and could be performed with higher precision by inclusion of echocardiography derived LASRa as a surrogate measure of PCWP. Insufficient LV compliance results in the inability to cope with increased cardiac preload. Nt-proBNP is secreted when the myocardium is stretched, however only a small portion of patients within the CHF group (study 3) had a high PCWP at rest. Nearly half of the study population with elevated NT-proBNP showed increased PCWP during PLL, which is indicative of underlying ventricular stiffness. By performing this preload increasing maneuver, patients predisposed to developing high filling pressure during supine cycling could be identified with high sensitivity and specificity. Echocardiography, in comparison with RHC, is more accessible, safer and requires less resources and time, thus is an appealing option in the quest to identify additional, non-invasive methods reflective of invasive pressures, which could be useful in the assessment of filling pressure during different loading conditions. LAVI at rest, LASRa and E/LVSRe during PLL, proved independently related to PCWP during PLL.
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