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    Die Stenosierung des rechtsventrikulären Ausflusstraktes beim Hund, eine klinische und morphologische Studie (2001)

    Art
    Hochschulschrift
    Autor
    Aslani, Mohammad Kaarji
    Quelle
    Berlin, 2001 — 139 Seiten
    Kontakt
    Klinik für kleine Haustiere

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    Abstract / Zusammenfassung

    For present work, 40 dogs with pulmonary stenosis of varying severity were investigated. Thirteen dogs had one (n= 10) or more (n=3) anomalies in addition to pulmonary stenosis. The most common additional anomaly, aortic stenosis, was observed in six cases, followed by a high ventricular septal defect with an overriding aorta (tetralogy of Fallot) in four cases.The dogs were divided into three groups according to the stenosis-related pressure gradient. Group 1 (n=7) comprised all dogs with a pressure gradient of /= 80 mmHg.The investigated animals were also divided into four groups according to age. Age group 1 (age < 1/2 year) consisted of 9 dogs, age group 2 (age 1/2-2 years) of 19 dogs, age group 3 (age 2-5 years) of 8 dogs, and age group 4 (age >/= 5 years) of 4 dogs. The total population consisted of 25 male and 15 female dogs.Thirty-eight of the 40 dogs were purebred, and 21 different breeds were represented. The West Highland white terrier was the most strongly represented breed (n=7), followed by the Staffordshire terrier (n=5) and the boxer (n=4).Decreased exercise tolerance (n=16) was, by far, the most common finding. Syncope was observed in six cases; cyanosis and retarded development were observed in four cases each. All the investigated dogs had pulmonary murmurs during systole. Five of the dogs exhibited an additional diastolic component. The loudness of the systolic murmur was 4th to 5th degree in thirty-two cases, 3rd degree in seven cases, and 2nd degree in one case.Axis deviation of over 103° (n=27) as well as S wave amplitudes of >0.8 mV in V2 (n=28) and of >0.7 mV in V4 (n=29) were the most common ECG features of a right-ventricular hypertrophy, The ECG was indicative of right ventricular hypertrophy in 20 dogs of group Ill, in 7 dogs of group 11, and in 3 dogs of group 1. The ECGs for these animals contained three or more of the ECG features of right ventricular hypertrophy specified by Hill 1971 and Trautvetter et aL 1981b.The chest X-rays demonstrated enlargement of the right ventricle in a total of 37 cases, The hypertrophy was mainly moderate (n=17) The level of right ventricular pressure was predominantly mild in groups 1 and II and moderate to severe in Group III. Poststenotic dilatation of the pulmonary artery (n=25), hypovascularization of the pulmonary arteries (n= 19), and congestion of the caudal vena cava (n=3 0) were also observed.The right ventricular posterior wall (RVPW), left ventricular posterior wall (LVPW), and ventricular septum of 29 dogs were measured by 2D echocardiography A RVPW L~ ratio of over 0.5 indicative of R~ hypertrophy was detected in two animals of group 1 and in all animals of the other two groups Of the 28 dogs with a pulmonary valve that could be assessed by echocardiography, 16 had thickening of only one or both visible semilunar valves; commissural fusion of the semilunar valves was additionally observed in 12 dogs.Narrowing of the left ventricular diameter in diastole was observed in groups II (n=4) and III (n= 11 >/= Dyskinesia of the ventricular septum was detected in a total of 22 cases. Most of these dogs (n= 15) belonged to group 111.Doppler studies were performed in a total of 37 dogs. The lowest transvalvular peak velocity in the pulmonary artery was 2.1 m/sec, whereas the highest was 7 m/sec, The minimum ejection fraction was 0.20 sec and the maximum 0,31 see. Pressure gradient-dependent extension of the ejection time was not observed. Regurgitation through the pulmonary valve was observed in 25 cases. Twenty-eight animals had tricuspid insufficiency of varying severity.Valvular pulmonary stenosis was detected in all ten dogs studied by angiocardiography. The right ventricular outflow tract was clearly hypertrophied in nine cases. Poststenotic dilatation was detected in all cases. Three of the dogs had additional anomalies. There was one case each of subaortic ventricular septal defect, aneurysm of the atrial septum, and dysplasia of the tricuspid valve. A persistent left vena cava cranialis.was detected in two cases.Five dogs with severe pulmonary stenosis (group Ill) were treated by interventional balloon valvuloplasty. The pulmonary pressure gradient was reduced by more than 50% in four of these animals. In the fifth case, the balloon dilatation achieved only a slight pressure reduction of 121 mmHg to 100 mmHg.Macroscopic morphological investigations were performed in five cases. These tests revealed valvular pulmonary stenosis in all heart specimens studied. Moderate to severe thickening of the valves was detected along with partial or complete fusion of the valves. One valvular diaphragm was partially separated by balloon catheterization. Additional anomalies weredetected in three cases (ventricular septal defect, tricuspid dysplasia, atrial septal aneurysm andpersistent ductus arteriosus)