Assessment of Pulmonary Blood Flow in Heart Failure. Using Novel and Non-Invasive Diagnostic Methods.

In heart failure (HF), the heart is unable to pump effectively in order to satisfy the demands of the body. The elevated filling pressure seen in HF leads to accumulation of fluid in the lungs, i.e pulmonary congestion. While investigation with chest X-ray is recommended, it has limitations in detecting pulmonary congestion. Ventilation/perfusion single-photon emission computed tomography (V/P SPECT), i.e tomographic lung scintigraphy, is a promising method to diagnose and quantify pulmonary congestion in HF but needs to be validated by invasive right-heart catheterization. The variation of the blood volume in the pulmonary circulation measured by magnetic resonance imaging (MRI) may also have the potential to quantify the severity of HF.The general aim of this thesis was to develop and validate new non-invasive methods to diagnose and quantify pulmonary congestion and variation of the pulmonary blood flow in patients with HF, as well as to follow-uppulmonary congestion.Paper I revealed that the degree of pulmonary congestion in HF could be diagnosed and quantified using V/P SPECT. It was validated with right-heart catheterization. V/P SPECT was more accurate than chest X-ray in diagnosing pulmonary congestion in HF.In Paper II V/P SPECT showed that the pulmonary perfusion pattern was improved and that V/P SPECT could be used to follow treatment effect after heart transplantation in patients with HF and quantify the degree of pulmonarycongestion. It was validated with right-heart catheterization.Paper III demonstrated that V/P SPECT could be used to follow treatment effect and assess the degree of pulmonary congestion in patients with HF after receiving cardiac resynchronization therapy (CRT). V/P SPECT was associated with improvement in patients’ symptoms.Paper IV showed that the pulmonary blood volume variation differed between patients with HF and healthy controls. In patients with HF, approximately 40% of the variation could be explained by the left ventricular longitudinal contribution to stroke volume and the phase shift between the in- and outflow to the pulmonary circulation. The remaining variation (60%) likely occur on a small vessel level.In summary, pulmonary congestion in HF is difficult to quantify objectively. The non-invasive methods V/P SPECT and MRI might add complementary information in the diagnosis of HF. V/P SPECT can be used to follow treatment effects after heart transplantation and CRT and may have a role in avoiding invasive right-heart catheterization in selected cases and aid in treatment decision

The brain-enriched microRNA miR-124 in plasma predicts neurological outcome after cardiac arrest

Introduction: Early prognostication after successful cardiopulmonary resuscitation is difficult, and there is a need for novel methods to estimate the extent of brain injury and predict outcome. In this study, we evaluated the impact of the cardiac arrest syndrome on the plasma levels of selected tissue-specific microRNAs (miRNAs) and assessed their ability to prognosticate death and neurological disability. Methods: We included 65 patients treated with hypothermia after cardiac arrest in the study. Blood samples were obtained at 24 hours and at 48 hours. For miRNA-screening purposes, custom quantitative polymerase chain reaction (qPCR) panels were first used. Thereafter individual miRNAs were assessed at 48 hours with qPCR. miRNAs that successfully predicted prognosis at 48 hours were further analysed at 24 hours. Outcomes were measured according to the Cerebral Performance Category (CPC) score at 6 months after cardiac arrest and stratified into good (CPC score 1 or 2) or poor (CPC scores 3 to 5). Results: At 48 hours, miR-146a, miR-122, miR-208b, miR-21, miR-9 and miR-128 did not differ between the good and poor neurological outcome groups. In contrast, miR-124 was significantly elevated in patients with poor outcomes compared with those with favourable outcomes (P < 0.0001) at 24 hours and 48 hours after cardiac arrest. Analysis of receiver operating characteristic curves at 24 and 48 hours after cardiac arrest showed areas under the curve of 0.87 (95% confidence interval (CI) = 0.79 to 0.96) and 0.89 (95% CI = 0.80 to 0.97), respectively. Conclusions: The brain-enriched miRNA miR-124 is a promising novel biomarker for prediction of neurological prognosis following cardiac arrest

Diagnosis of acute coronary occlusion using computed electrocardiographic imaging based on the 12-lead electrocardiogram, in comparison with ST- elevation myocardial infarction criteria

Introduction: Computed electrocardiographic imaging (CEI) is a method that uses ST- segment deviations from the 12-lead electrocardiogram (ECG) and has been tested on a small number of patients.Aim: To extend the testing material of the CEI method and deduce a threshold using ECGs recorded pre- and during acute occlusion. The performance of the CEI and ST elevation myocardial infarction (STEMI) criteria will be compared. Method: Two CEI images were generated from each of 99 patients before and during complete occlusion in the left anterior descending (LAD), right coronary artery (RCA) and left circumflex coronary artery (LCx). Result: The sensitivity and specificity of STEMI criteria was 61% and 96% respectively for the whole occlusion group. The sensitivities and specificities were 74 %, 97% (LAD); 60%, 94% (RCA); 35%, 100% (LCx) respectively, for STEMI criteria. A threshold of 998 units was deduced from the CEI method. Conclusion: The CEI method has similar diagnostic performance of an occlusion as STEMI criteria

Förbättrar "ST/HR-loopar" bedömning av ischemi vid arbets-EKG hos kvinnor?

Arbetsutlöst myokardischemi kan diagnostiseras med arbetsprovet, främst genom parametern ST60-sänkning under arbete samt återhämtningsfasen. Tidigare studier har visat arbetsprovets låga diagnostiska förmåga av arbetsutlöst myokardischemi och klassificerat det som en osäker metod, speciellt för kvinnor, och få studier har gjorts på kvinnor för förbättring. En justering av ST60-sänkning med hänsyn till hjärtfrekvensen (HR) har gjorts i flera studier, i försök att utveckla diagnostiken. När hjärtfrekvensen ritas grafiskt mot ST60- sänkning erhålls en ST/HR loop bestående av arbetsfasen och återhämtningsfasen. Den normaliserade arean (NA), som erhålls från ST/HR- loopen, är ett mått på sannolikheten för ischemi och dess grad. Studiens syfte är att, utifrån ST/HR loopars NA-värden från arbetselektrokardiogram, avgöra om diagnostiken av ischemi hos kvinnor kan förbättras i jämförelse med den konventionella bedömningen som baseras på ST60-sänkningen i slutet av arbete. Myokardscintigrafi (facitmetoden) och arbetsprov har utförts på den klinisk fysiologiska avdelningen i lund. Kontrollgruppen bestod av 80 kvinnor med normal myokardscintigrafi medan gruppen ”sjuka” omfattar 26 patienter som med myokardscintigrafi bedömts ha arbetsutlöst myokardischemi. För att i denna studie påvisa om det föreligger en statistisk skillnad mellan sjuka och friska, gällande NA – värdet respektive ST60-sänkningen, användes t-testet. En skillnad mellan sjuka och friska med NA- värde kunde inte påvisas och den konventionella bedömningen med ST60-sänkning visade sig inte heller vara bättre än NA-värdet för bedömning av arbetsutlöst myokardischemi. Nyckelord: arbets- EKG, myokardischemi, myokardscintigrafi, normaliserad area, ST60- sänkning, ST/HR- loop.Exercise induced myocardial ischemia can be diagnosed with exercise–ECG, mainly through the parameter ST60-depression during the exercise and recovery phases. However, its low diagnostic accuracy, especially in women, has been proven. An adjustment of the ST60-depression with the heart rate has been done in several studies to develop the diagnosis. When the heart rate is plotted against the ST60-depression, an ST/HR- loop is obtained where both the exercise and recovery phases are included. The normalised area (NA) of the loop is believed to be significant for the diagnosis of ischemia. The aim of the study is to decide if the diagnosis of ischemia in women can be improved with the normalised area of the loop, from exercise– ECG, compared to the conventional assessment with ST60-depression at the end of exercise. Myocardial scintigraphy (the reference method) and exercise- ECG have been performed at the department of clinical physiology in Lund. The control group included 80 women with a normal myocardial scintigraphy while the other group consists of 26 patients who, according to their myocardial scintigraphy, have exercise induced myocardial ischemia. A distinction between the groups could not be made with the normalised area. The conventional assessment with ST60-depression was not better than the normalised area for the assessment of myocardial ischemia. Key words: Exercise- ECG, myocardial ischemia, myocardial scintigraphy, normalised area, ST60- depression, ST/HR-loop

Pulmonary perfusion and NYHA classification improve after cardiac resynchronization therapy

Background: Evaluation of cardiac resynchronization therapy (CRT) often includes New York Heart Association (NYHA) classification, and echocardiography. However, these measures have limitations. Perfusion gradients from ventilation/perfusion single-photon emission computed tomography (V/P SPECT) are related to left-heart filling pressures and have been validated against invasive right-heart catheterization. The aim was to assess if changes in perfusion gradients are associated with improvements in heart failure (HF) symptoms after CRT, and if they correlate with currently used diagnostic methods in the follow-up of patients with HF after receiving CRT. Methods and results: Nineteen patients underwent V/P SPECT, echocardiography, NYHA classification, and the quality-of-life scoring system “Minnesota living with HF” (MLWHF), before and after CRT. CRT caused improvement in perfusion gradients from V/P SPECT which were associated with improvements in NYHA classification (P =.0456), whereas improvements in end-systolic volume (LVESV) from echocardiography were not. After receiving CRT, the proportion of patients who improved was lower using LVESV (n = 7/19, 37%) than perfusion gradients (n = 13/19, 68%). Neither change in perfusion gradients nor LVESV was associated with changes in MLWHF (P = 1.0, respectively). Conclusions: Measurement of perfusion gradients from V/P SPECT is a promising quantitative user-independent surrogate measure of left-sided filling pressure in the assessment of CRT response in patients with HF

The brain-enriched microRNA miR-124 in plasma predicts neurological outcome after cardiac arrest

Introduction: Early prognostication after successful cardiopulmonary resuscitation is difficult, and there is a need for novel methods to estimate the extent of brain injury and predict outcome. In this study, we evaluated the impact of the cardiac arrest syndrome on the plasma levels of selected tissue-specific microRNAs (miRNAs) and assessed their ability to prognosticate death and neurological disability. Methods: We included 65 patients treated with hypothermia after cardiac arrest in the study. Blood samples were obtained at 24 hours and at 48 hours. For miRNA-screening purposes, custom quantitative polymerase chain reaction (qPCR) panels were first used. Thereafter individual miRNAs were assessed at 48 hours with qPCR. miRNAs that successfully predicted prognosis at 48 hours were further analysed at 24 hours. Outcomes were measured according to the Cerebral Performance Category (CPC) score at 6 months after cardiac arrest and stratified into good (CPC score 1 or 2) or poor (CPC scores 3 to 5). Results: At 48 hours, miR-146a, miR-122, miR-208b, miR-21, miR-9 and miR-128 did not differ between the good and poor neurological outcome groups. In contrast, miR-124 was significantly elevated in patients with poor outcomes compared with those with favourable outcomes (P < 0.0001) at 24 hours and 48 hours after cardiac arrest. Analysis of receiver operating characteristic curves at 24 and 48 hours after cardiac arrest showed areas under the curve of 0.87 (95% confidence interval (CI) = 0.79 to 0.96) and 0.89 (95% CI = 0.80 to 0.97), respectively. Conclusions: The brain-enriched miRNA miR-124 is a promising novel biomarker for prediction of neurological prognosis following cardiac arrest

Effect of exercise on the plasma vesicular proteome : A methodological study comparing acoustic trapping and centrifugation

Extracellular vesicles (EVs) are a heterogeneous group of actively released vesicles originating from a wide range of cell types. Characterization of these EVs and their proteomes in the human plasma provides a novel approach in clinical diagnostics, as they reflect physiological and pathological states. However, EV isolation is technically challenging with the current methods having several disadvantages, requiring large sample volumes, and resulting in loss of sample and EV integrity. Here, we use an alternative, non-contact method based on a microscale acoustic standing wave technology. Improved coupling of the acoustic resonator increased the EV recovery from 30% in earlier reports to 80%, also displaying long term stability between experiment days. We report a pilot study, with 20 subjects who underwent physical exercise. Plasma samples were obtained before and 1 h after the workout. Acoustic trapping was compared to a standard high-speed centrifugation protocol, and the method was validated by flow cytometry (FCM). To monitor the device stability, the pooled frozen plasma from volunteers was used as an internal control. A key finding from the FCM analysis was a decrease in CD62E+ (E-selectin) EVs 1 h after exercise that was consistent for both methods. Furthermore, we report the first data that analyse differential EV protein expression before and after physical exercise. Olink-based proteomic analysis showed 54 significantly changed proteins in the EV fraction in response to physical exercise, whereas the EV-free plasma proteome only displayed four differentially regulated proteins, thus underlining an important role of these vesicles in cellular communication, and their potential as plasma derived biomarkers. We conclude that acoustic trapping offers a fast and efficient method comparable with high-speed centrifugation protocols. Further, it has the advantage of using smaller sample volumes (12.5 μL) and rapid contact-free separation with higher yield, and can thus pave the way for future clinical EV-based diagnostics