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Jakob Lundgreen Willesen has a total of 434 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Speckle-Tracking Echocardiography in Dogs: Evaluating Imaging Parameters and Methodological Variability in Global Longitudinal Strain Assessment

    by Jonas E. Mogensen, Maiken B. T. Bach, Pernille G. Bay, Tuğba Varlik, Jakob L. Willesen, Caroline H. Gleerup, Jørgen Koch

    Two-dimensional speckle-tracking echocardiography (2D-STE) is an advanced imaging technique that offers quantitative insights into myocardial function by analyzing the motion of speckles created during ultrasound–tissue interactions. This study aims to evaluate the reliability of 2D-STE by examining the impact of key technical parameters on global longitudinal strain (GLS) measurement accuracy and comparing two speckle-tracking analysis methods provided by GE Healthcare: quantitative analysis of the 2D strain (2D strain) and automated function imaging (AFI). The prospective study consisted of two cohorts. In the first cohort, including 16 healthy dogs, the influence of frame rate, heart rate variation, zoom, transducer frequency, and image foreshortening on speckle-tracking values was assessed. In the second cohort, which included 10 healthy dogs, 2D-STE parameters were obtained with the 2D strain and AFI to assess agreement between the methods and observer variability. Our findings indicate that foreshortening (p < 0.01, Cohen’s d: 0.52, CI: −17.81 to −24.83) and heart rate variability (p = 0.02, Cohen’s d: 0.72, CI: −18.07 to −26.23) significantly affect speckle-tracking measurements. While zoom, frame rate, and frequency did not show a significant impact. Additionally, while the 2D strain and AFI exhibited a strong correlation, a significant systematic bias was identified, with AFI underestimating strain values compared to the 2D strain. Intra- and inter-observer coefficients of variation (CV) were below 9% for both methods, supporting their reliability. These findings emphasize the need to optimize image acquisition and selection criteria, which enhances the accuracy and reliability of the speckle-tracking analysis.


  • Open Access

    Quantification of Mitral Valve Regurgitation in Cavalier King Charles Spaniels and Chihuahuas Using Radius of Proximal Isovelocity Surface Area

    by Jørgen Koch, Inge V. Engeland, Jakob L. Willesen, Anders S. Schrøder, Caroline H. Gleerup, Maiken B. T. Bach

    Mitral regurgitation (MR) resulting from myxomatous mitral valve disease (MMVD) is a prevalent condition in dogs, particularly smaller breeds like Cavalier King Charles Spaniels (CKCSs) and Chihuahuas (CHHs). An accurate assessment of MR severity is essential for effective treatment and disease monitoring, yet a standardized method has yet to be established. In this retrospective study, we evaluated 124 client-owned dogs diagnosed with MMVD, including 64 CKCSs and 60 CHHs. Dogs were categorized into three stages: asymptomatic (B1), remodeled (B2), and congestive heart failure (CHF, C). The MR severity was quantified using the proximal isovelocity surface area (PISA) method, specifically focusing on the PISA radius (PISA-r). The PISA-r measurements exhibited significant increases across disease stages and demonstrated strong correlations with echocardiographic parameters (ranging from 0.83 to 0.94), including the left atrial size and left ventricular internal diameter. The receiver operating characteristic (ROC) curve analysis revealed the high sensitivity and specificity of PISA-r in classifying disease stages, establishing optimal cut-off values. The method displayed excellent repeatability (interobserver variability: 0.95) and reproducibility (intraobserver variability: 0.97). In conclusion, the PISA method, specifically PISA-r, was reliable for assessing MR severity in dogs with MMVD. By simplifying the diagnosis and management of MR, this research can potentially improve the life and management of MMVD-affected dogs.


  • Open Access

    Fasting triglyceride concentrations are associated with markers of lipid metabolism and glucose homeostasis in healthy, non-obese dogs in lean and overweight condition

    by Carlos Gomez-Fernandez-Blanco, Dominique Peeters, Frédéric Farnir, Katja Höglund, Vassiliki Gouni, Maria Wiberg, Jakob Lundgren Willesen, Sofia Hanås, Kathleen McEntee, Laurent Tiret, et al.

    Serum triglyceride concentrations increase in dogs with obesity, which is typically assessed by body condition score (BCS), however little is known about changes that take place in non-obese dogs in overweight condition. Further, the associations of triglyceride levels with other markers of energy homeostasis are poorly characterised in healthy animals. The present study aimed to evaluate associations between both BCS and triglyceride concentrations with other markers of lipid and glucose metabolism in healthy, non-obese dogs, as well as to assess whether these markers change significantly in non-obese dogs with overweight as compared to their lean counterparts. Serum concentrations of cholesterol, free fatty acids, triglycerides, insulin, glucose and fructosamine were measured in 532 healthy, client-owned dogs, assigned either to ‘lean’ (BCS: 3–5) or ‘overweight’ (BCS: 6–7) categories. Generalised linear mixed models were used to assess associations between BCS categories, triglyceride concentrations and other variables, correcting for the effect of breed. Compared with lean dogs, overweight dogs had a greater serum cholesterol concentration (95% CI, 5.3–6.2 mmol/L or 205–237 mg/dL versus 5.1–5.4 mmol/L or 198–210 mg/dL, p = 0.0032), insulin concentration (95% CI, 17.5–22.1 μU/ml versus 16.7–18.0 μU/ml, p = 0.0374) and were older (95% CI, 4.0–5.3 versus 3.4–3.7 years, p = 0.0005). Triglyceride concentrations were positively associated with fructosamine (r2 = 0.31, p = 0.0012), cholesterol (r2 = 0.25, p < 0.0001), insulin (r2 = 0.14, p = 0.0030) and glucose (r2 = 0.10, p = 0.0014) concentrations, and negatively associated with free fatty acid concentrations (r2 = 0.11, p < 0.0001). However, there was no association between triglyceride concentrations and age. In conclusion, both BCS and triglyceride concentrations were associated with other markers of glucose and lipid metabolism in non-obese healthy dogs, amongst which those with overweight showed metabolic changes as compared to their lean counterparts. Triglyceride concentrations were associated with an increase in insulin and fructosamine concentrations that might reflect an early-phase impairment in glucose tolerance which, surprisingly, was concurrent with lower basal free fatty acid concentrations.


  • ECHOCARDIOGRAPHY IN THIRTY AMERICAN FLAMINGOS (PHOENICOPTERUS RUBER) AND A CASE OF SUSPECTED NEURALLY MEDIATED REFLEX SYNCOPE

    by Anders S. Schrøder, Jakob L. Willesen, Kathryn L. Perrin, Mads F. Bertelsen, Jørgen Koch

    Heart disease in birds contributes to premature death and is usually detected postmortem. Echocardiography is a sensitive and noninvasive diagnostic modality but reported standard values for many species of birds, including American flamingos (Phoenicopterus ruber), are unavailable. Echocardiography was opportunistically performed on 30 unsedated American flamingos during their annual routine health examination. Structural heart disease was not found in any of the examined birds. However, 18 birds showed varying degrees of dynamic intraventricular obstruction. Echocardiographic parameters are reported. Benign neurocardiogenic weakness or syncopal events during handling were suspected in three birds. Stress combined with an intraventricular obstruction is believed to have triggered a cascade of parasympathetic innervation and sympathetic inhibition, similar to neurally mediated reflex syncope in humans.


  • Clinical bleeding diathesis, laboratory haemostatic aberrations and survival in dogs infected with Angiostrongylus vasorum: 180 cases (2005‐2019)

    by A. S. Thomsen, M. P. Petersen, J. L. Willesen, M. B. T. Bach, I. N. Kieler, A. T. Kristensen, J. Koch, L. N. Nielsen

    Objectives: Bleeding diathesis is a complication in dogs infected with Angiostrongylus vasorum. This retrospective study investigated clinical and laboratory haemostatic differences in A. vasorum‐positive dogs with and without signs of bleeding and impact of bleeding on survival.Materials and Methods: Demographics, type of clinical bleeding, haematocrit and a range of haemostatic tests, including thromboelastography and derived velocity curves were retrospectively registered from A. vasorum‐positive dogs. All parameters were compared between dogs with and without signs of bleeding using univariable analyses. Binomial and multinomial regression models were applied to examine specific indicators in the bleeding dogs. P‐values were false discovery rate adjusted, and adjusted PA. vasorum‐positive dogs with bleeding diathesis. Bleeding was identified as an important negative prognostic indicator in A. vasorum‐positive dogs.


  • Open Access

    Dirofilaria repens in a dog imported to Denmark: A potential for emerging zoonotic disease

    by Asger Lundorff Jensen, Anne Kirstine Havnsøe Krogh, Jo Fjeldsted-Holm Lundsgaard, Jakob Lundgren Willesen, Janne Graarup-Hansen Lyngby, Anders Simon Schrøder, Maiken Bayer Thode Bach, Rebecca P.K.D. Berg


  • Open Access

    Evaluation of cardiac troponin I as a predictor of death in critically ill cats

    by Lena Pelander, Maiken B. T. Bach, Ingrid Ljungvall, Jakob L. Willesen, Jörgen Koch, Kristoffer Dreimanis, Amalie Telling, Rikke M. Damsgard, Åsa Ohlsson, Jens Häggström, et al.

    Background: Abnormally high serum cardiac troponin I (cTnI) concentration, reflecting leakage from or necrosis of cardiomyocytes, is a negative prognosticator for death in dogs. Objectives: To investigate in critically ill cats whether serum cTnI concentration is abnormally high, identify conditions associated with abnormally high cTnI concentrations, and evaluate cTnI as an independent prognosticator for death and a potential coprognosticator to the acute patient physiologic and laboratory evaluation (APPLE) score in cats. Animals: One hundred nineteen cats admitted to intensive care units (ICU) and 13 healthy cats at 2 university teaching hospitals. Methods: Prospective study. Clinical examinations were performed, APPLE scores calculated, and serum cTnI and serum amyloid A (SAA) measured within 24 hours after admission. Outcome was defined as death/euthanasia or survival to discharge, 28 and 90 days after ICU-admission. Prognostic capacity of cTnI, APPLE scores and models combining cTnI and scores were evaluated by receiver-operator-characteristic analyses. Results: Median (IQR) serum cTnI concentration was higher in ill (0.63 [0.18-2.65] ng/mL) compared to healthy (0.015 [0.005-0.041] ng/mL) cats (P < .001) and higher in subgroups with structural cardiac disease (2.05 [0.54-16.59] ng/mL; P < .001) or SAA >5 mg/L (0.84 [0.23-2.81] ng/mL; P = .009) than in cats without these characteristics (0.45 [0.12-1.70] and 0.35 [0.015-0.96] ng/mL). The in-hospital case fatality rate was 29%. Neither serum cTnI concentration for all critically ill cats (area-under-the-curve 0.567 [95% CI 0.454-0.680], n = 119) or subgroups (0.625 [0.387-0.863], n = 27; 0.506 [0.360-0.652], n = 86), nor APPLE scores (fast 0.568 [0.453-0.682], full 0.585 [0.470-0.699], n = 100), were significant prognosticators for death. Conclusions and Clinical Importance: Abnormally high serum cTnI concentration was common in critically ill cats. Unlike in dogs, cTnI did not confer prognostic information regarding death.


  • Outcome clinical audit: analyses of interventional closure of patent ductus arteriosus in dogs

    by M. Martin, B. Pedro, D. Dickson, J. Neves, J. Harris, Y. Martinez-Pereira, M.I. Oliveira, J.L. Willesen, L. Vatne, G.J. Culshaw, et al.


  • Open Access

    Hemostatic Dysfunction in Dogs Naturally Infected with Angiostrongylus vasorum—A Narrative Review

    by Jakob L. Willesen, Rebecca Langhorn, Lise N. Nielsen

    This narrative review aims to describe Angiostrongylus vasorum-induced hemostatic dysfunction of dogs with emphasis on clinical and laboratory findings as well as potential therapeutic strategies for the bleeding patient. Canine angiostrongylosis (CA) is a disease with potentially high morbidity and mortality in endemic areas and with fatal outcome often associated with either severe respiratory compromise, pulmonary hypertension and right-sided heart failure, or hemostatic dysfunction with severe bleeding. The most common signs of hemorrhage are hematomas, petecchiation, ecchymoses, oral mucosal membrane bleeding and scleral bleeding, while intracranial and pulmonary hemorrhage are among the most severe. The pathophysiological mechanisms underlying hemostatic dysfunction in these patients are presently researched. While the larval effect on platelets remains unknown, the parasite appears to induce dysregulation of hemostatic proteins, with studies suggesting a mixture of pro-coagulant protein consumption and hyperfibrinolysis. Importantly, not all dogs display the same hemostatic abnormalities. Consequently, characterizing the hemostatic state of the individual patient is necessary, but has proven difficult with traditional coagulation tests. Global viscoelastic testing shows promise, but has limited availability in general practice. Treatment of A. vasorum-infected dogs with hemostatic dysfunction relies on anthelmintic treatment as well as therapy directed at the individual dog’s specific hemostatic alterations.