Veterinary echocardiographers' preferences for left atrial size assessment in cats: the BENEFIT project.

INTRODUCTION/OBJECTIVES: Veterinary echocardiographers' preferences for left atrial (LA) size assessment in cats have not been systematically investigated. The primary aim of this prospective exploratory study was to investigate echocardiographers' preferences concerning LA size assessment in cats. A secondary aim was to investigate echocardiographers' preferences for assessing LA size in subgroups based on geographic, demographic, and professional profiles. ANIMALS, MATERIALS, AND METHODS: An online survey instrument was designed, verified, and distributed globally to veterinary echocardiographers. RESULTS: A total of 655 veterinary echocardiographers from six continents and 54 countries, working in specialty practice (56%) and in general practice (38%), provided data. Linear two-dimensional (2D) technique was favored by most echocardiographers (n = 612) for LA size assessment. Most commonly, respondents combined linear 2D with subjective assessment (n = 227), while 209 used linear 2D-based methods alone. Most echocardiographers using linear 2D-based methods preferred the right parasternal short-axis view and to index the LA to the aorta (Ao). Approximately 10% of the respondents obtained LA dimensions from a right parasternal long-axis four-chamber view. Approximately one-third of echocardiographers that made linear measurements from 2D echocardiograms shared the same preferences regarding cat position, acquisition view, indexing method and time point identification for the LA measurement. The responses were comparably homogeneous across geographic location, level of training, years performing echocardiography, and type of practice. DISCUSSION/CONCLUSION: Most veterinary echocardiographers assessed LA size in cats using linear 2D echocardiography from a right parasternal short-axis view, and indexed LA to Ao. Respondents' preferences were similar over geographic, demographic, and professional backgrounds.

Veterinary echocardiographers' preferences for left atrial size assessment in dogs: the BENEFIT project.

INTRODUCTION/OBJECTIVES: Veterinary echocardiographers' preferences for left atrial (LA) size assessment in dogs have never been systematically investigated. The primary aim of this international survey study was to investigate echocardiographers' preferences for LA size assessment in dogs. The secondary aim was to investigate echocardiographers' preferences for assessing LA size in subgroups based on geographic, demographic, and professional profiles. ANIMALS, MATERIALS, AND METHODS: An online survey instrument was designed, verified, and distributed globally to the veterinary echocardiographers. RESULTS: A total of 670 echocardiographers from 54 countries on six continents completed the survey. Most echocardiographers (n = 621) used linear two-dimensional (2D)-based methods to assess LA size, 379 used subjective assessment, and 151 used M-mode-based methods. Most commonly, echocardiographers combined linear 2D-based methods with subjective assessment (n = 222), whereas 191 used linear 2D-based methods alone. Most echocardiographers (n = 436) using linear 2D-based methods preferred the right parasternal short-axis view and indexed the LA to the aorta. Approximately 30% (n = 191) of the echocardiographers who performed linear measurements from 2D echocardiograms shared the same preferences regarding dog position, acquisition view, indexing method, and identification of the time-point used for the measurement. The responses were comparably homogeneous across geographic location, training level, years of performing echocardiography, and type of practice. DISCUSSION/CONCLUSION: Most veterinary echocardiographers assessed LA size in dogs using linear 2D echocardiography from a right parasternal short-axis view, and by indexing the LA to the aorta. The respondents' preferences were similar across geographic, demographic, and professional backgrounds.

Neuromuscular blockade in patients with ARDS: a rapid practice guideline.

The aim of this Intensive Care Medicine Rapid Practice Guideline (ICM-RPG) is to formulate an evidence-based guidance for the use of neuromuscular blocking agents (NMBA) in adults with acute respiratory distress syndrome (ARDS). The panel comprised 20 international clinical experts from 12 countries, and 2 patient representatives. We adhered to the methodology for trustworthy clinical practice guidelines and followed a strict conflict of interest policy. We convened panelists through teleconferences and web-based discussions. Guideline experts from the guidelines in intensive care, development, and evaluation Group provided methodological support. Two content experts provided input and shared their expertise with the panel but did not participate in drafting the final recommendations. We followed the Grading of Recommendations Assessment, Development, and Evaluation approach to assess the certainty of evidence and grade recommendations and suggestions. We used the evidence to decision framework to generate recommendations. The panel provided input on guideline implementation and monitoring, and suggested future research priorities. The overall certainty in the evidence was low. The ICM-RPG panel issued one recommendation and two suggestions regarding the use of NMBAs in adults with ARDS. Current evidence does not support the early routine use of an NMBA infusion in adults with ARDS of any severity. It favours avoiding a continuous infusion of NMBA for patients who are ventilated using a lighter sedation strategy. However, for patients who require deep sedation to facilitate lung protective ventilation or prone positioning, and require neuromuscular blockade, an infusion of an NMBA for 48 h is a reasonable option.

Design and rationale of the atrial fibrillation occurring transiently with stress (AFOTS) incidence study.

BACKGROUND: Atrial fibrillation (AF) is often detected for the first time in patients hospitalized for medical illness or non-cardiovascular surgery. AF occurring transiently with stress (AFOTS) describes this manifestation of AF, which may either be the result of a non-cardiac stressor, or existing paroxysmal AF that was not previously detected. Current estimates of AFOTS incidence are imprecise: ranging from 1 to 44%, owing to the marked heterogeneity in patient populations, identification and methods used to detect AFOTS. METHODS: The prospective, two-centre epidemiological AFOTS Incidence study will enroll 250 consecutive participants without a history of AF but with at increased risk of AF (Age ≥ 65 or >50 with one risk factor for AF) admitted to intensive care units (ICUs) for medical illness or non-cardiac surgery. Upon admission, participants will wear an ECG patch monitor that will remain in place for 14 days, or until discharge from hospital. Patients' consent to participation is deferred for up to 72 h after admission. The primary endpoint is the incidence of AF lasting ≥30 s. The study is powered to detect an AF incidence of 17% ±â€¯5%. RESULTS: We conducted a vanguard feasibility study, and 55 participants have completed participation. The median duration of monitoring was seven days. AF was detected by the clinical team in 8 participants (14%; 95% Confidence Interval 7-26%). CONCLUSIONS: The AFOTS Incidence study will employ a systematic and highly sensitive protocol for detecting AFOTS in medical illness and non-cardiac surgery ICU patients. This study is feasible and will provide a reliable estimate of the true incidence of AFOTS in this population.

Reliability and validity of self-reported questionnaires to measure pain and disability in adults with neck pain and its associated disorders: part 3-a systematic review from the CADRE Collaboration.

PURPOSE: To determine the reliability and validity of self-reported questionnaires to measure pain and disability in adults with grades I-IV neck pain and its associated disorders (NAD). METHODS: We updated the systematic review of the 2000-2010 Bone and Joint Decade Task Force on Neck Pain and its Associated Disorders and systematically searched databases from 2005 to 2017. Independent reviewers screened and critically appraised studies using standardized tools. Evidence from low-risk-of-bias studies was synthesized according to best evidence synthesis principles. Validity studies were ranked according to the Sackett and Haynes classification. RESULTS: We screened 2823 articles, and 26 were eligible for critical appraisal; 18 were low risk of bias. Preliminary evidence suggests that the Neck Disability Index (original and short versions), Whiplash Disability Questionnaire, Neck Pain Driving Index, and ProFitMap-Neck may be valid and reliable to measure disability in patients with NAD. We found preliminary evidence for the validity and reliability of pain measurements including the Body Pain Diagram, Visual Analogue Scale, the Numeric Rating Scale and the Pain-DETECT Questionnaire. CONCLUSION: The evidence supporting the validity and reliability of instruments used to measure pain and disability is preliminary. Further validity studies are needed to confirm the clinical utility of self-reported questionnaires to assess pain and disability in patients with NAD. These slides can be retrieved under Electronic Supplementary Material.

Steroids in cardiac surgery: a systematic review and meta-analysis.

BACKGROUND: Cardiopulmonary bypass (CPB) induces a systemic inflammatory reaction that may contribute to postoperative complications. Preventing this reaction with steroids may improve outcomes. We performed a systematic review to evaluate the impact of prophylactic steroids on clinical outcomes in patients undergoing on-pump cardiac surgery. METHODS: We searched MEDLINE, EMBASE, and Cochrane CENTRAL for randomised controlled trials (RCTs) comparing perioperative corticosteroid administration with a control group in adults undergoing CPB. Outcomes of interest included mortality, myocardial infarction, and new onset atrial fibrillation. We assessed the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Fifty-six RCTs published between 1977 and 2015 were included in this meta-analysis. Mortality was not significantly different between groups [3.0% (215/7258 patients) in the steroid group and 3.5% (252/7202 patients) in the placebo group; relative risk (RR), 0.85; 95% confidence interval (CI), 0.71-1.01; P=0.07; I2 = 0%]. Myocardial injury was more frequent in the steroid group [8.0% (560/6989 patients), compared with 6.9% (476/6929 patients); RR, 1.17, 95% CI, 1.04-1.31; P=0.008; I2=0%]. New onset atrial fibrillation was lower in the steroid group [25.7% (1792/6984 patients) compared with 28.3% (1969/6964 patients), RR, 0.91, 95% CI, 0.86-0.96, P=0.0005, I2=43%]; this beneficial effect was limited to small trials (P for interaction <0.00001). CONCLUSIONS: After randomising 16 013 patients, steroid administration at the time of cardiac surgery had an unclear impact on mortality, increased the risk of myocardial injury, and the impact on atrial fibrillation should be viewed with caution given that large trials showed no effect.

Protocol adherence for continuously titrated interventions in randomized trials: an overview of the current methodology and case study.

BACKGROUND: The standard definition for protocol adherence is the proportion of all scheduled doses that are delivered. In clinical research, this definition has several limitations when evaluating protocol adherence in trials that study interventions requiring continuous titration. DISCUSSION: Building upon a specific case study, we analyzed a recent trial of a continuously titrated intervention to assess the impact of different definitions of protocol deviations on the interpretation of protocol adherence. The OVATION pilot trial was an open-label randomized controlled trial of higher (75-80 mmHg) versus lower (60-65 mmHg) mean arterial pressure (MAP) targets for vasopressor therapy in shock. In this trial, potential protocol deviations were defined as MAP values outside the targeted range for >4 consecutive hours during vasopressor therapy without synchronous and consistent adjustments of vasopressor doses. An adjudication committee reviewed each potential deviation to determine if it was clinically-justified or not. There are four reasons for this contextual measurement and reporting of protocol adherence. First, between-arm separation is a robust measure of adherence to complex protocols. Second, adherence assessed by protocol deviations varies in function of the definition of deviations and the frequency of measurements. Third, distinguishing clinically-justified vs. not clinically-justified protocol deviations acknowledges clinically sensible bedside decision-making and offers a clear terminology before the trial begins. Finally, multiple metrics exist to report protocol deviations, which provides different information but complementary information on protocol adherence. CONCLUSIONS: In trials of interventions requiring continuous titration, metrics used for defining protocol deviations have a considerable impact on the interpretation of protocol adherence. Definitions for protocol deviations should be prespecified and correlated with between-arm separation, if it can be measured.

Reliability and validity of clinical tests to assess the anatomical integrity of the cervical spine in adults with neck pain and its associated disorders: Part 1-A systematic review from the Cervical Assessment and Diagnosis Research Evaluation (CADRE) Collaboration.

OBJECTIVE: To determine the reliability and validity of clinical tests to assess the anatomical integrity of the cervical spine in adults with neck pain and its associated disorders. METHODS: We updated the systematic review of the 2000-2010 Bone and Joint Decade Task Force on Neck Pain and its Associated Disorders. We also searched the literature to identify studies on the reliability and validity of Doppler velocimetry for the evaluation of cervical arteries. Two independent reviewers screened and critically appraised studies. We conducted a best evidence synthesis of low risk of bias studies and ranked the phases of investigations using the classification proposed by Sackett and Haynes. RESULTS: We screened 9022 articles and critically appraised 8 studies; all 8 studies had low risk of bias (three reliability and five validity Phase II-III studies). Preliminary evidence suggests that the extension-rotation test may be reliable and has adequate validity to rule out pain arising from facet joints. The evidence suggests variable reliability and preliminary validity for the evaluation of cervical radiculopathy including neurological examination (manual motor testing, dermatomal sensory testing, deep tendon reflexes, and pathological reflex testing), Spurling's and the upper limb neurodynamic tests. No evidence was found for doppler velocimetry. CONCLUSIONS: Little evidence exists to support the use of clinical tests to evaluate the anatomical integrity of the cervical spine in adults with neck pain and its associated disorders. We found preliminary evidence to support the use of the extension-rotation test, neurological examination, Spurling's and the upper limb neurodynamic tests.

Efficacy and safety of inhaled anaesthetic for postoperative sedation during mechanical ventilation in adult cardiac surgery patients: a systematic review and meta-analysis.

The aim was to evaluate the efficacy and safety of volatile anaesthetic for postoperative sedation in adult cardiac surgery patients through a systematic review and meta-analysis. We retrieved randomized controlled trials from MEDLINE, EMBASE, CENTRAL, Web of Science, clinical trials registries, conference proceedings, and reference lists of included articles. Independent reviewers extracted data, including patient characteristics, type of intraoperative anaesthesia, inhaled anaesthetic used, comparator sedation, and outcomes of interest, using pre-piloted forms. We assessed risk of bias using the Cochrane Tool and evaluated the strength of the evidence using the GRADE approach. Eight studies enrolling 610 patients were included. Seven had a high and one a low risk of bias. The times to extubation after intensive care unit (ICU) admission and sedation discontinuation were, respectively, 76 [95% confidence interval (CI) -150 to - 2, I2=79%] and 74 min (95% CI - 126 to - 23, I2=96%) less in patients who were sedated using volatile anaesthetic. There was no difference in ICU or hospital length of stay. Patients who received volatile anaesthetic sedation had troponin concentrations that were 0.71 ng ml-1 (95% CI 0.23-1.2) lower than control patients. Reporting on other outcomes was varied and not suitable for meta-analysis. Volatile anaesthetic sedation may be associated with a shorter time to extubation after cardiac surgery but no change in ICU or hospital length of stay. It is associated with a significantly lower postoperative troponin concentration, but the impact of this on adverse cardiovascular outcomes is uncertain. Blinded randomized trials using intention-to-treat analysis are required. PROSPERO registry number: 2016:CRD42016033874. Available from http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42016033874.

Aortoseptal angle and pressure gradient reduction following balloon valvuloplasty in dogs with severe subaortic stenosis.

INTRODUCTION: To determine the relationship between aortoseptal angle (AoSA) and the short- and long-term systolic pressure gradient (PG) reduction following combined cutting and high-pressure balloon valvuloplasty (CB/HPBV) in dogs with severe subaortic stenosis. ANIMALS: Retrospective study of 22 client-owned dogs of various breeds with severe subaortic stenosis (mean left ventricular to aortic PG = 143 mmHg; range = 80-322 mmHg) that underwent CB/HPBV. MATERIALS AND METHODS: Initial angiographic and left apical and right-sided parasternal long-axis view echocardiographic video loops were used for measuring the angle between the plane of the interventricular septum and the longitudinal axis of the ascending aorta. The PG reduction ratio immediately after CB/HPBV and 6 and 12 months later were compared with AoSA. RESULTS: Weak correlations were observed for all instances of PG reduction ratio and AoSA type. Significantly greater mean differences of PG reduction ratio were observed for angles >160° than for angles <160° at 24 h (>160° mean: 54.45, standard error [SE]: ±3.8; <160° mean: 39.88, SE: ±2.09), 6 months (>160° mean: 57.73, SE: ±10.9; <160° mean: 28.22, SE: ±3.42), and 12 months (>160° mean: 76.11, SE: ±17.5; <160° mean: 27.61, SE: ±6.44; p=0.003). CONCLUSIONS: Dogs with AoSA >160° on right-sided parasternal long-axis view echocardiograms responded with a greater PG reduction following CB/HPBV than did dogs with AoSA <160°. This suggests that AoSA is associated with long-term outcomes of CB/HPBV, and measurement could help in the evaluation of dogs that are candidates for CB/HPBV.

Bidirectional effect of CD200 on breast cancer development and metastasis, with ultimate outcome determined by tumor aggressiveness and a cancer-induced inflammatory response.

CD200 acts through its receptor (CD200R) to inhibit excessive inflammation. The role of CD200-CD200R1 interaction in tumor immunity is poorly understood. In this study, we examined the role of CD200-CD200R1 interaction in the progression and metastasis of highly aggressive 4THM murine-breast carcinoma using CD200 transgenic (CD200(tg)) and CD200R1 knock-out (CD200R1(-)(/-)) BALB/c mice. 4THM cells induce extensive visceral metastasis and neutrophil infiltration in affected tissues. CD200 overexpression in the host was associated with decreased primary tumor growth and metastasis, whereas lack of CD200R1 expression by host cells was associated with enhanced visceral metastasis. Absence of CD200R1 expression led to decreased tumor-infiltrating-cytotoxic T cells and increased the release of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-6. In contrast, CD200 overexpression led to increased tumor-induced interferon-γ and IL-10 response and decreased TNF-α and IL-6 release. Neutrophil infiltration of tissues was markedly decreased in CD200(tg) animals and increased in CD200R1(-/-) mice. These findings are contradictory to what has been reported in the EMT6 mouse breast-cancer model. Other distinguishing features of tumor elicited by EMT6 and 4THM cell injections were also examined. Visceral tissues from mice bearing EMT6 tumors showed a lack of neutrophil infiltration and decreased IL-6 release in CD200R1(-/-) mice. EMT6 and 4THM cells also differed in vimentin expression and in vitro migration rate, which was markedly lower in EMT6 tumors. These results support the hypothesis that CD200 expression can alter immune responses, and can inhibit metastatic growth of tumor cells that induce systemic and local inflammatory response. Increasing CD200 activity/signaling might be an important therapeutic strategy for treatment of aggressive breast carcinomas.

Association between aortoseptal angle in Golden Retriever puppies and subaortic stenosis in adulthood.

BACKGROUND: Predicting subaortic stenosis (SAS) in adult Golden Retriever dogs (GRs) by evaluating them as puppies is hampered by the progressive expression of the SAS phenotype in youth. In some children who develop SAS as adults, an abnormal aortoseptal angle (AoSA) precedes development of stenosis. OBJECTIVES: To determine the normal AoSA in young adult GRs using echocardiography; to assess the value of AoSA in GR puppies for predicting development of the SAS phenotype. ANIMALS: Forty-eight 2- to 6-month-old GR puppies. METHODS: Prospective study. Puppies were recruited from clients and breeders. Puppies were evaluated with a physical examination and an echocardiogram, and this evaluation was repeated when they were 12-18-month-old adults. Puppies were classified as unaffected (WNL) or affected (SAS) retroactively, based on their results as adults. RESULTS: In WNL young adult GRs, mean ± SD AoSA was 152.3 ± 6.5°. Mean ± SD AoSA in SAS puppies (144.9 ± 8.6°) was significantly different from mean AoSA in WNL puppies (155.7 ± 8.8°, P < .01). No puppy with AoSA >160° had the SAS phenotype as a young adult; 93% (75.7-99.1%) of puppies with AoSA <145° had the SAS phenotype as young adults. Peak LVOT velocity increased significantly between evaluations (P < .0001) whereas AoSA did not (P = .45). CONCLUSION AND CLINICAL SIGNIFICANCE: A steep AoSA in GR puppies is associated with the SAS phenotype in young adulthood. Some GR puppies have an abnormal AoSA that persists in young adulthood and is detectable before peak LVOT velocity reaches levels consistent with SAS.

Prostate cancer and its mimics at multiparametric prostate MRI.

One in six males will develop prostate cancer during their lifetime. Prostate cancer is the second leading cause of cancer death in American males, behind only lung cancer. Unfortunately, even though this disease is so common, clinical screening methods such as prostate-specific antigen test and transrectal ultrasound-guided prostate biopsy lack sensitivity and specificity in diagnosing prostate cancer. In recent years, multiparametric prostate MRI has emerged as a very important tool in the diagnosis of prostate carcinoma with a high accuracy. However, diagnostic difficulty is often encountered even with an experienced abdominal radiologist. That is mainly because many normal and abnormal entities can mimic prostate carcinoma at multiparametric MRI. Therefore, the purpose of this pictorial review is to discuss the usefulness of multiparametric prostate MRI in the diagnosis of prostate carcinoma, emphasizing the key MRI features that help to make a distinction of prostate carcinoma from its mimics.

Histological characterization of dilated cardiomyopathy in the juvenile toy Manchester terrier.

Dilated cardiomyopathy (DCM), the most common form of cardiomyopathy in the dog, most often occurs in certain breeds. The objective of this study was to describe a rapidly progressive form of DCM that has been recently recognized in juvenile Toy Manchester Terrier dogs (TMTs). The clinical history and gross findings were reviewed in a group of 14 TMTs, and histologic sections of heart were examined in 12 of those 14 TMTs with DCM. Histochemical and histomorphometric analyses were employed to compare the heart in TMTs affected by DCM with that of control dogs. TMTs ranged in age from 10 to 58.3 weeks, with males and females being equally affected. Affected TMT hearts contained foci of degeneration and loss of myofibers with fibrosis and mild lymphoplasmacytic infiltrates. Less prominent features included foci of acute myofiber degeneration and necrosis with or without intralesional mineralization and mild to moderate suppurative and lymphoplasmacytic infiltrates. Morphometric quantification demonstrated that the right ventricle was more severely affected (P ≤ .05) than the left ventricle with variable involvement of the interventricular septum. Immunohistochemistry for canine parvovirus was negative in all heart samples. However, the absence of parvoviral antigen does not rule out a possible viral or autoimmune cause. The presence of these myocardial lesions among closely related dogs suggests a genetic contribution to this disease process in the TMT.

Multi-Parametric MRI-Directed Focal Salvage Permanent Interstitial Brachytherapy for Locally Recurrent Adenocarcinoma of the Prostate: A Novel Approach.

Even with the technological advances of dose-escalated IMRT with the addition of the latest image guidance technologies, local failures still occur. The combination of MRI-based imaging techniques can yield quantitative information that reflects on the biological properties of prostatic tissues. These techniques provide unique information that can be used for tumor detection in the treated gland. With the advent of these improved imaging modalities, it has become possible to more effectively image local recurrences within the prostate gland. With better imaging, these focal recurrences can be differentially targeted with salvage brachytherapy minimizing rectal and bladder toxicity. Here we report a novel use of MRI-directed focal brachytherapy after local recurrence. This technique offers a unique opportunity to safely and successfully treat recurrent prostate cancer, previously treated with definitive radiation therapy. The use of multi-parametric MRI-directed focal salvage permanent interstitial brachytherapy for locally recurrent adenocarcinoma of the prostate is a promising strategy to avoid more aggressive and expensive treatments that are associated with increased morbidity, potentially improving survival at potentially lower costs.

Ventricular tachyarrhythmias in 106 cats: associated structural cardiac disorders.

BACKGROUND: Ventricular tachyarrhythmias occur in association with cardiac and extracardiac disorders in many species of animals, but information identifying concurrent disorders in cats with such arrhythmias is scarce. METHODS: We investigated coexisting diseases by retrospectively evaluating medical records of cats with ventricular tachyarrhythmias seen during a 51-month period at 1 institution. For comparative purposes, we evaluated records of dogs with similar arrhythmias during the same time period. All cats and dogs had premature ventricular complexes, accelerated idioventricular rhythm, ventricular tachycardia, or some combination of these arrhythmias, and all had undergone echocardiography during the same visit that led to the diagnosis of ventricular tachyarrhythmia. RESULTS AND CONCLUSIONS: Most (102/106; 96%) cats had at least 1 echocardiographically apparent abnormality concurrent with ventricular tachyarrhythmias. Ventricular tachyarrhythmias in cats were most commonly associated with myocardial disease (eg, left ventricular concentric hypertrophy [n = 66], restrictive or unclassified cardiomyopathy [n = 17], and dilated cardiomyopathy [n = 6]). When comparing dogs and cats that had ventricular tachyarrhythmias and were diagnosed on the same clinical service of the same institution, an echocardiographically apparent cardiac lesion was seen more often in cats (102/106, 96%) than in dogs (95/138, 69%) (P < .001).

Cardiogenic shock and cardiac arrest.

Severe heart disease may cause hypotension and hypoperfusion, and ultimately circulation may cease altogether. These two clinical syndromes are cardiogenic shock and cardiac arrest, respectively. This review summarizes the causes and clinical features of each, and describes the treatment options available to clinicians managing patients in cardiogenic shock.

Long-term clinical management of right-to-left ("reversed") patent ductus arteriosus in 3 dogs.

A small number of dogs with patent ductus arteriosus (PDA) have right-to-left flow of blood through the ductus, leading to polycythemia and clinical signs associated with hyperviscosity. Three dogs with right-to-left-shunting PDA are described. Treatment consisted solely of phlebotomy, performed on an outpatient basis when indicated by exacerbation of clinical signs, for a total of 11-68 times on each dog. Each treatment entailed the removal of a mean of 19% (maximum 28%) of circulating blood volume, divided into 2 phlebotomies several hours apart, without intravenous fluid replacement. Subjectively, marked clinical improvement was noted. Intermittent clinical signs decreased in frequency and severity in all dogs. Adverse effects were rare (1 for 98 phlebotomies) and reversible. Dogs lived > 2 to > 8 years during treatment. Outpatient phlebotomy without fluid replacement was safe, and was associated with subjective improvement and prolonged survival in these dogs.