A systematic study of a myocardial lesion: Colliquative myocytolysis

Vitality markers in forensic investigations: a literature review

Determining whether an injury was sustained in life or not is one of the most important topics in forensic medicine. Morphological, cytological, and biological techniques are used to assess wound vitality. Several markers involved in vital and supravital reactions increase the accuracy of wound age estimation. This systematic review aimed to investigate the main vitality markers used in forensic medicine to date. This review was conducted by performing a systematic literature search on online resources (PubMed Central database and Google Scholar) until May 2022. We identified 46 articles published between 1987 and May 2022, analyzing a total of 53 markers. Based on the data of this review, the most studied vitality markers were adhesion molecules (fibronectin, p-selectin, CD 15), pro-inflammatory cytokines (IL-6, IL-1β, TNF-α), cathepsin D, tryptase, and microRNAs (miRNAs). The most interesting studies were based on animal models: the different markers were investigated through immunohistochemical and qRT-PCR methods. The experimental methods were usually based on skin incisions, ligature marks, and burned skin areas. To date, it has not been possible to identify any gold standard markers based on the criteria of efficacy, specificity, and reliability; however, studies are still in progress. In the future, the use of miRNAs is promising as well as the combination of multiple markers. In this way, it will be possible to increase the sensitivity and specificity to validate systems or models for determining wound vitality in forensic practice.

Is Takotsubo cardiomyopathy still looking for its own nosological identity?

Despite several efforts to provide a proper nosological framework for Takotsubo cardiomyopathy (TCM), this remains an unresolved matter in clinical practice. Several clinical, pathophysiologic and histologic findings support the conceivable hypothesis that TCM could be defined as a unique pathologic entity, rather than a distinct subset of myocardial infarction with non-obstructive coronary arteries. Further investigations are needed in order to define TCM with the most appropriate disease taxonomy.

TLR7 Activation Accelerates Cardiovascular Pathology in a Mouse Model of Lupus

We report a novel model of lupus-associated cardiovascular pathology accelerated by the TLR7 agonist R848 in lupus-prone B6.Sle1.Sle2.Sle3 (TC) mice. R848-treated TC mice but not non-autoimmune C57BL/6 (B6) controls developed microvascular inflammation and myocytolysis with intracellular vacuolization. This histopathology was similar to antibody-mediated rejection after heart transplant, although it did not involve complement. The TC or B6 recipients of serum or splenocytes from R848-treated TC mice developed a reactive cardiomyocyte hypertrophy, which also presents spontaneously in old TC mice as well as in TC.Rag-/- mice that lack B and T cells. Each of these cardiovascular lesions correspond to abnormalities that have been reported in lupus patients. Lymphoid and non-lymphoid immune cells as well as soluble factors contribute to lupus-associated cardiovascular lesions in TC mice, which can now be dissected using this model with and without R848 treatment.

Heart Rate Variability and Sympathetic Activity Is Modulated by Very Low-Calorie Ketogenic Diet

Obesity is characterized by an energy imbalance and by the accumulation of visceral adipose tissue. The energy balance is controlled by a complex set of balanced physiological systems that provide hunger and satiety signals to the brain and regulate the body’s ability to consume energy. The central nervous system controls the metabolic state, influencing the activity of other systems and receiving information from them. Heart rate variability (HRV) is the natural variability of the heart rate in response to several factors. HRV is related to the interaction between the SNS and the parasympathetic. In the light of this evidence, the aim of this study is to investigate the possible effects of the two different dietary regimens such as very low-calorie ketogenic diet (VLCKD) vs. low caloric diet (LCD), on the functions of the nervous system, with particular attention to the autonomous control of heart rate variability (HRV). A total of 26 obese subjects underwent diet therapy in order to reduce body weight; they were also randomly divided into two groups: the VLCKD group and the LCD group. Our results showed that in both groups, there is a reduction in heart rate as an indicator of sympathetic activity; we found a statistically significant variation only in the VLCKD group. Therefore, this study supports the notion that the sympathovagal balance can be modulated by a specific diet, but further studies are needed to clarify the molecular pathway undergoing this modulation.

Sudden Cardiac Death and Ex-Situ Post-Mortem Cardiac Magnetic Resonance Imaging: A Morphological Study Based on Diagnostic Correlation Methodology

During the last years, post-mortem imaging has gradually been assumed within research in the field of forensic pathology. This role appears to be clearly and simply applied in the trauma field with the use of conventional radiography or Post Mortem Computed Tomography (PMCT). Recently, particular attention was paid to cardiovascular imaging using Post Mortem Magnetic Resonance Imaging (PMMRI). The present experimental study aims to: (i) confirm the efficacy of a Post Mortem Cardiac Resonance Imaging (PMCRI) study protocol for the study of human hearts collected during the autopsy; (ii) apply the defined protocol on subjects who died of “SCD (sudden cardiac death)”, to identify alterations that could guide subsequent sampling. Two hearts of healthy subjects (A: male 22 years; B: female 26 years), who died from causes other than SCD were collected and compared to hearts that belonged to SCD individuals (C: male, 47 years old; D: female, 44 years old; E: male; 72 years old). The exams were performed on a 1.5 T scanner (Philips Intera Achieva, Best, the Netherlands) on hearts collected during autopsy and after a 30-day formalin fixation. Two readers analyzed the obtained images blindly and after randomization. From the comparison between the data from imaging and the macroscopic and histological investigations carried out, the present study proved the effectiveness of a PMMRI protocol to study ex-situ hearts. Moreover, it suggested the following semeiology in post-mortem SCD cases: the hyperintense area with indistinct margins in the Short Tau Inversion Recovery (STIR) sequence was linked to edema or area of pathological fibers, whereas the hypointense area in the T2-FFE sequences was linked to fibrosis. PMMRI can provide a valuable benefit to post-mortem investigations, helping to distinctly improve the success rate of histological sampling and investigations, which remains the gold standard in the diagnosis of sudden death.

State-of-Art in the Age Determination of Venous Thromboembolism: A Systematic Review

Venous thromboembolism (VTE), consisting of deep vein thrombosis (DVT) and pulmonary embolism (PE), requires a forensic age determination to ascertain their causal relationship with recent events, such as trauma or medical treatment. The main objective of this systematic review is to identify the current state-of-the-art immunohistochemical methods for age determination of fatal VTE. A literature search was performed through different databases, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Within the study, we have selected only cases represented by deceased patients for DVT and/or PTE in which thromboembolic material was collected during an autoptic examination and then subjected to a histological and an immunohistochemical investigation. Studies based on animal models were not included. We assessed bias risk. A database-based search produced a total of 19 articles. After excluding duplicate items from the selection, 14 articles were reviewed. Ten articles were excluded because they did not meet the inclusion criteria. The results have pointed out 4 studies that were included in the present analysis for a total of 157 samples of DVT and 171 PTE samples. These were analyzed using traditional histological and immunohistochemical techniques. The results must be interpreted with a critical eye because of their heterogeneity in terms of time, geography, and study design. The present review highlights the importance of associating specific immunohistochemical markers with a histological analysis for the timing of DVT/PTE fatal events. Further future experiences will hopefully endorse actual knowledge on the subject to increase the accuracy in the assessment of thrombus-embolus age.

Pharmacogenetics and Forensic Toxicology: A New Step towards a Multidisciplinary Approach

Pharmacogenetics analyzes the individual behavior of DNA genes after the administration of a drug. Pharmacogenetic research has been implemented in recent years thanks to the improvement in genome sequencing techniques and molecular genetics. In addition to medical purposes, pharmacogenetics can constitute an important tool for clarifying the interpretation of toxicological data in post-mortem examinations, sometimes crucial for determining the cause and modality of death. The purpose of this systematic literature review is not only to raise awareness among the forensic community concerning pharmacogenetics, but also to provide a workflow for forensic toxicologists to follow in cases of unknown causes of death related to drug use/abuse. The scientific community is called on to work hard in order to supply evidence in forensic practice, demonstrating that this investigation could become an essential tool both in civil and forensic contexts. The following keywords were used for the search engine: (pharmacogenetics) AND (forensic toxicology); (pharmacogenetics) AND (post-mortem); (pharmacogenetics) AND (forensic science); and (pharmacogenetics) AND (autopsy). A total of 125 articles were collected. Of these, 29 articles were included in this systematic review. A total of 75% of the included studies were original articles (n = 21) and 25% were case reports (n = 7). A total of 78% (n = 22) of the studies involved deceased people for whom a complete autopsy was performed, while 22% (n = 6) involved people in good health who were given a drug with a subsequent pharmacogenetic study. The most studied drugs were opioids (codeine, morphine, and methadone), followed by antidepressants (tricyclic antidepressants and venlafaxine). Furthermore, all studies highlighted the importance of a pharmacogenetics study in drug-related deaths, especially in cases of non-overdose of drugs of abuse. This study highlights the importance of forensic pharmacogenetics, a field of toxicology still not fully understood, which is of great help in cases of sudden death, deaths from overdose, deaths after the administration of a drug, and also in cases of complaint of medical malpractice.

The Role of Very Low Calorie Ketogenic Diet in Sympathetic Activation through Cortisol Secretion in Male Obese Population

Adipose tissue is considered an endocrine organ, and its excess compromises the immune response and metabolism of hormones and nutrients. Furthermore, the accumulation of visceral fat helps to increase the synthesis of cortisol. The hypothalamus-pituitary-adrenal (HPA) axis is a neuroendocrine system involved in maintaining homeostasis in humans under physiological conditions and stress, and cortisol is the main hormone of the HPA axis. It is known that a stress-induced diet and cortisol reactivity to acute stress factors may be related to dietary behavior. In obesity, to reduce visceral adipose tissue, caloric restriction is a valid strategy. In light of this fact, the aim of this study was to assess the effects of a commercial dietary ketosis program for weight loss on the sympathetic nervous system and HPA axis, through evaluation of salivary cortisol and GSR levels. Thirty obese subjects were recruited and assessed before and after 8 weeks of Very Low Calorie Ketogenic Diet (VLCKD) intervention to evaluate body composition and biochemical parameters. Salivary cortisol levels and GSR significantly decreased after dietary treatment; in addition, body composition and biochemical features were ameliorated. The VLCKD had a short-term positive effect on the SNS and HPA axes regulating salivary cortisol levels. Finally, the effects of the VLCKD on the SNS and HPA axis may lead to more individualized treatment strategies that integrate obesity and stress and support the usefulness of such therapeutic interventions in promoting the reduction of the individual disease burden.

Forensic Post-Mortem Investigation in AAS Abusers: Investigative Diagnostic Protocol. A Systematic Review

Anabolic–androgenic steroids (AASs) are a group of synthetic molecules derived from testosterone and its precursors. AASs are widely used illicitly by adolescents and athletes, especially by bodybuilders; AASs are among the most used drugs for improving physical performance, as well as for aesthetic purposes. The use of AASs by professional and recreational athletes is increasing worldwide. This review focused on deaths related to AAS abuse and to investigation of the autopsy results and histopathological findings using a rigorous methodology protocol covering: a complete autopsy, histological analysis, and a broad toxicological investigation. Moreover, we aimed to define an investigative diagnostic protocol supporting forensic pathologists during the post-mortem investigation of AAS abusers. This review was conducted using PubMed Central and Google Scholar databases to find articles published between 1 January 1968 and 30 June 2021, using the following key terms: “(anabolic-androgenic steroids) AND (autopsy); (anabolic-androgenic steroids) AND (forensic)”. A total of 939 articles were screened and 926 did not meet the inclusion criteria. In conclusion, 14 articles were included in this systematic review, reporting 137 fatal cases of AAS abuse in total. The histopathologic studies showed myocardial damage characterized by myocyte hypertrophy, focal myocyte damage with myofibrillar loss, interstitial fibrosis, mostly subepicardial, and small vessel disease. Indeed, in AAS-related cases, autopsy plays a pivotal role in the study of AAS adverse effects and organ damage related to their use or abuse. This systematic review aimed to define a specific workflow in death cases related to AASs, suggesting important future insights to better clarify sudden deaths related to AASs, such as the use of miRNAs. The forensic community needs a unified approach in cases of suspected death related to the use of AASs. There are several occasions to apply this workflow, for example in cases of death of bodybuilders and of young people who die in gymnasiums or during sports activities.

Myofibrillolysis and fibrosis predicts myocardial insufficiency

Introduction

Cardiocyte myofibrillolysis and interstitial fibrosis belong to histopathological changes in cardiomyopathies, leading to heart failure.

Aim

To evaluate these changes in apical resection during left ventricular assist device (LVAD) implantation.

Material and methods

The studied group consisted of 40 patients with cardiomyopathy, and apical samples excised during left ventricular assist device implantation were studied (CM/VAD group, mean: 48.1 ±10 y/o). A control group consisted of 6 apical samples from healthy heart graft donors (mean: 29 ±2.3 years old). Area fraction (AF) was calculated for: fibrosis, cardiocytes with myofibrillolysis (MFL), non-myofibrillolytic cardiocytes (non-MFL).

Results

Single lymphocytes were seen in 18 (45%) cases in the CM/VAD group. Cardiomyopathy grade evaluated semiquantitatively in CM/VAD was: slight (25% of a group), moderate (35.5%), advanced (35.5%). CM/VAD cases showed nearly ten times higher fibrosis than the control group. The MFL cells occupied nearly a five times larger area in CM/VAD than in the control group, whereas non-MFL cells were found in the control group, as a predominant pattern. The linear regression calculated between fibrosis AF and types of cardiocytes indicated the depletion of cardiomyocytes with fibrosis increase. The control group presented insignificant dependency between fibrosis and MFL cells, suggesting the lack of replacement fibrosis. Significant negative dependence between fibrosis and non-MFL cardiocytes suggested remodeling in controls. Correlation analysis showed a strong relation between depletion of normal cardiocytes and progression of fibrosis.

Conclusions

Progression of cardiomyopathy and fibrosis depends on the loss of cardiocytes rather than degeneration of these cells.

Genome-wide DNA methylation encodes cardiac transcriptional reprogramming in human ischemic heart failure

Ischemic cardiomyopathy (ICM) is the clinical endpoint of coronary heart disease and a leading cause of heart failure. Despite growing demands to develop personalized approaches to treat ICM, progress is limited by inadequate knowledge of its pathogenesis. Since epigenetics has been implicated in the development of other chronic diseases, the current study was designed to determine whether transcriptional and/or epigenetic changes are sufficient to distinguish ICM from other etiologies of heart failure. Specifically, we hypothesize that genome-wide DNA methylation encodes transcriptional reprogramming in ICM. RNA-sequencing analysis was performed on human ischemic left ventricular tissue obtained from patients with end-stage heart failure, which enriched known targets of the polycomb methyltransferase EZH2 compared to non-ischemic hearts. Combined RNA sequencing and genome-wide DNA methylation analysis revealed a robust gene expression pattern consistent with suppression of oxidative metabolism, induced anaerobic glycolysis, and altered cellular remodeling. Lastly, KLF15 was identified as a putative upstream regulator of metabolic gene expression that was itself regulated by EZH2 in a SET domain-dependent manner. Our observations therefore define a novel role of DNA methylation in the metabolic reprogramming of ICM. Furthermore, we identify EZH2 as an epigenetic regulator of KLF15 along with DNA hypermethylation, and we propose a novel mechanism through which coronary heart disease reprograms the expression of both intermediate enzymes and upstream regulators of cardiac metabolism such as KLF15.

Cardiac CD47 drives left ventricular heart failure through Ca2+-CaMKII-regulated induction of HDAC3

Background

Left ventricular heart failure (LVHF) remains progressive and fatal and is a formidable health problem because ever‐larger numbers of people are diagnosed with this disease. Therapeutics, while relieving symptoms and extending life in some cases, cannot resolve this process and transplant remains the option of last resort for many. Our team has described a widely expressed cell surface receptor (CD47) that is activated by its high‐affinity secreted ligand, thrombospondin 1 (TSP1), in acute injury and chronic disease; however, a role for activated CD47 in LVHF has not previously been proposed.

Methods and Results

In experimental LVHF TSP1‐CD47 signaling is increased concurrent with up‐regulation of cardiac histone deacetylase 3 (HDAC3). Mice mutated to lack CD47 displayed protection from transverse aortic constriction (TAC)‐driven LVHF with enhanced cardiac function, decreased cellular hypertrophy and fibrosis, decreased maladaptive autophagy, and decreased expression of HDAC3. In cell culture, treatment of cardiac myocyte CD47 with a TSP1‐derived peptide, which binds and activates CD47, increased HDAC3 expression and myocyte hypertrophy in a Ca²⁺/calmodulin protein kinase II (CaMKII)‐dependent manner. Conversely, antibody blocking of CD47 activation, or pharmacologic inhibition of CaMKII, suppressed HDAC3 expression, decreased myocyte hypertrophy, and mitigated established LVHF. Downstream gene suppression of HDAC3 mimicked the protective effects of CD47 blockade and decreased hypertrophy in myocytes and mitigated LVHF in animals.

Conclusions

These data identify a proximate role for the TSP1‐CD47 axis in promoting LVHF by CaKMII‐mediated up‐regulation of HDAC3 and suggest novel therapeutic opportunities.

Clinical history and colliquative myocytolysis are keys to the diagnosis of shoshin beriberi

Cardiovascular beriberi presents as either the fulminant (Shoshin beriberi) or chronic form. Shoshin beriberi is a rare disease that may lead to a fatal outcome if the patient does not receive appropriate treatment. In the present report, we describe the case of a 66-year-old man presenting with leg edema and dyspnea at rest. Clinical presentations were nonalcoholic Shoshin beriberi and lactate accumulation; however, clinical improvement was observed after the administration of thiamine. His pretherapy thiamine level (2.1  μ g/dL) was consistent with a diagnosis of beriberi. Based on the findings of the present case, we believe that a diagnosis can be made in patients with a clinical history that is consistent with that of Shoshin beriberi, combined with low thiamine levels, lactate accumulation, and colliquative myocytolysis. Learning Objective. Shoshin beriberi is often misdiagnosed because of its rarity; a detailed clinical history and characteristic myocardial histopathology changes may be useful for making a definite diagnosis.

Ischemia modified albumin increase indicating cardiac damage after experimental subarachnoid hemorrhage

Background

Cardiac complications are often developed after subarachnoid hemorrhage (SAH) and may cause sudden death of the patient. There are reports in the literature addressing ischemia modified albumin (IMA) as an early and useful marker in the diagnosis of ischemic heart events. The aim of this study is to evaluate serum IMA by using the albumin cobalt binding (ACB) test in the first, second, and seventh days of experimental SAH in rats.

Twenty-eight Wistar albino rats were divided into four groups each consisting of seven animals. These were classified as control group, 1st, 2nd and 7th day SAH groups. SAH was done by transclival basilar artery puncture. Blood samples were collected under anesthesia from the left ventricles of the heart using the cardiac puncture method for IMA measurement. Histopathological examinations were performed on the heart and lung tissues. Albumin with by colorimetric, creatine kinase (CK), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) were determined on an automatic analyser using the enzymatic method. IMA using by ACB test was detected with spectrophotometer.

Results

Serum IMA (p = 0.044) in seventh day of SAH were higher compared to the control group. Total injury scores of heart and lung tissue, also myocytolysis at day 7 were significantly higher than control group (p = 0.001, p = 0.001, p = 0.001), day 1 (p = 0.001, p = 0.001, p = 0.001) and day 2 (p = 0.001, p = 0.007, p = 0.001). A positive correlation between IMA - myocytolysis (r = 0.48, p = 0.008), and between IMA – heart tissue total injury score (r = 0.41, p = 0.029) was found.

Conclusion

The results revealed that increased serum IMA may be related to myocardial stress after SAH.

Comparison of Gal and non-Gal-mediated cardiac xenograft rejection

BACKGROUND

This study compares the pathologic condition of delayed xenograft rejection in Gal-positive and Gal-knockout cardiac xenografts after pig-to-baboon heterotopic cardiac xenotransplantation when the induced anti-Gal antibody response is unregulated, blocked, or absent.

METHODS

Baboon recipients of Gal-positive, CD46 pig hearts were treated with an αGal polymer (group 1; n=11) or Gal-specific immunoapheresis (group 2; n=8) to block anti-Gal antibody. Gal-knockout cardiac xenografts recipients (group 3; n=5) received no anti-Gal therapy. Perioperative and interim biopsies were examined and antibody responses were determined.

RESULTS

No hyperacute rejection was seen and histologic findings were similar across the groups. All groups showed vascular antibody deposition in perioperative and interim biopsies and in explant samples. A prominent antibody response was detected only in group 2. Complement activation was evident by C3d deposition but deposition of C5b and C5b-9 was limited. Earliest evidence of myocardial injury was myocyte vacuolization in the absence of microvascular thrombosis or coagulative necrosis that developed later. Histology of explanted hearts exhibited mainly microvascular thrombosis and coagulative necrosis with little evidence of interstitial hemorrhage or edema.

CONCLUSIONS

The histology of rejection seemed independent of the anti-Gal or non-Gal immune response. Myocyte vacuolization seems to be an early feature of delayed xenograft rejection presaging more classic pathologic features.

Cardiac beriberi: morphological findings in two fatal cases

Cardiovascular beriberi is categorized into two main groups, according to its cause: alcoholic and non-alcoholic (dietary). Cardiovascular beriberi can also be divided into a fulminant form (Shoshin beriberi) and a chronic form. Shoshin beriberi is characterized by hypotension, tachycardia, and lactic acidosis and is mainly encountered in non-alcoholic patients in Asian countries, although it has also been seen in alcoholics in Western countries. Due to the complex clinical presentation and to the lack of diagnostic tests, thiamine deficiency is still being missed, especially among non-alcoholics patients. We present two fatal cases of non - alcohol associated cardiac beriberi. An acute myocardial infarction was observed in one case; extensive colliquative myocytolisis (grade 2) was described in the second case respectively. Morphologically, myocardial necrosis and colliquative myocytolysis are the histologic hallmarks of this acute, rare clinical entity. An increase in apoptotic myocytes was demonstrated probably sustaining the cardiogenic shock.

Ischemic myocardial injuries after cardiac malformation repair in infants may be associated with oxidative stress mechanisms

BACKGROUND

Despite advances in pediatric cardiac surgery, perioperative myocardial injury can be the major determinant of postoperative dysfunction after cardiac surgery. This study investigated the pathology-related differences in 29 infants with congenital heart disease that led to death. The infants were treated at the University Hospital of Ribeirão Preto, Brazil.

METHODS

The patients were divided into four groups: Group 1, 16 infants who underwent operations for congenital heart disease on cardiopulmonary bypass; Group 2, four infants who underwent off-cardiopulmonary bypass operations for congenital heart disease; Group 3, nine infants who died from congenital heart disease prior to surgical treatment; and Group 4 (control group), five infants with no congenital heart disease and who died from other causes. The myocardial injuries and oxidative stress mechanisms were assessed by histopathology and immunohistochemistry and were quantified by morphometrical analyses.

RESULTS

Contraction band necrosis and dystrophic calcification were found primarily in infants of Group 1. Coagulation necrosis and healing were prominent in Group 2, while infants without repair (Group 3) showed mainly colliquative myocytolysis. Apoptotic cells were more prominent in the operative groups. The control group showed no significant myocardial lesions. Lipid peroxidation was the principal mechanism of oxidative stress accounting for the myocardial lesions.

CONCLUSION

The diversity of the lesions observed in these hearts seemed to indicate a large spectrum of cell damage due to inadequate myocardial perfusion, especially when these infants underwent surgery. Oxidative mechanisms could be a common mediator in the pathogenesis of myocardial injuries, mediated by peroxidation of the membrane phospholipids and resulting in changes in the permeability of the cell membrane, cell death, and intracellular calcium overload. Furthermore, an immature and often hypertrophied myocardium may promote unfavorable conditions, leading to heart failure and a lethal outcome.

Arteriosclerotic changes in the myocardium, lung, and kidney in dogs with chronic congestive heart failure and myxomatous mitral valve disease

BACKGROUND

The occurrence of small vessel arteriosclerosis in the myocardium, kidney, and lung in dogs with naturally occurring myxomatous mitral valve disease has not been previously investigated systematically.

METHODS

Twenty-one dogs with naturally occurring congestive heart failure and 21 age-matched, sex-matched, and weight-matched control dogs underwent extensive pathological and histopathological examination. Morphometry and scoring of tissue sections were used to measure arterial narrowing and fibrosis in the myocardium, kidney, and lung; and intimal thickness and plaque formation in the aorta and pulmonary artery.

RESULTS

Dogs with congestive heart failure had significantly more arterial narrowing in the left ventricle (P < .003), lung (P < .0001), and kidney (P < .02); intimal-medial thickening in the pulmonary artery (P = .04); and fibrosis in the left ventricle (P < .0001) than control dogs. However, they did not have more plaque formation or intimal-medial thickening in the aorta than controls. There was significantly more arterial narrowing in papillary muscles than in all other locations in dogs with congestive heart failure (P < .002). In control dogs, arterial changes were less pronounced and did not differ in different locations.

CONCLUSIONS

Dogs with naturally occurring myxomatous mitral valve disease have significantly more arterial changes in the myocardium, lung, and kidney, and significantly more fibrosis in the myocardium than control dogs. This could have important implications in the management of myxomatous mitral valve disease and raises interesting questions about the occurrence and importance of intramural small vessel disease in humans with primary mitral valve prolapse.