Tierärztliche Fakultät - Digitale Hochschulschriften der LMU - Teil 04/07 Archiv

Up to now, the occult phase of the cardiomyopathy in Doberman Pinschers, with a cumulative prevalence of 63 % in Europe (WESS et al., 2009b), can only be diagnosed by specialized and cost-intensive methods, such as the 24-h-ECG (Holter) and the echocardiogram. Electrocardiographic and echocardiographic changes usually appear at an age, in which the dogs were already used for breeding. Considering the genetic health of the Doberman Pinscher breed, it is of great importance to diagnose the genetically determined cardiomyopathy before it can be passed on to the offspring. The aim of this study Analysis of NTpro-BNP in Dilated Cardiomyopathy of the Doberman Pinscher was to evaluate NTpro-BNP in the Doberman Pinscher population, in healthy animals as well as in various stages of cardiomyopathy, to define reference values and to validate the use of NTpro-BNP as a diagnostic tool. Therefore, 250 healthy and 108 dogs with cardiomyopathy were studied between 2004 and 2008, in total 480 examinations. NTpro-BNP measurements were performed in plasma samples, using the ELISA VETSIGNTM Canine CardioSCREEN Ntpro-BNP, Guildhay Ltd., UK. NTpro-BNP concentrations increased in correlation with the severity of disease. There was a statistically significant difference between the healthy control group (mean 315.7 pmol/l) and the occult and decompensated groups as well as the whole dog population with cardiomyopathy. To differentiate healthy dogs from dogs with cardiomyopathy, a cut-off value of 413.8 pmol/l was established that provided an area under the receiver operator curve of 0.820, with a sensitivity and specifity of 72.4 % and 80.2 %, respectively. There was no significant influence of age, weight or sex on the NTpro-BNP concentration. Sensitivity reached 90.0 % for predicting abnormal echocardiographic changes. Interestingly, there was a statistically significant increase of NTpro-BNP in the occult group with exclusively VPCs even before echocardiographic changes were present. The “still normal” group, consisting of examinations of dogs that appeared to be healthy without any measurable signs at that time, but which later on developed cardiomyopathy, is highly interesting. Although the mean NTpro-BNP level (499.7 pmol/l) was higher than the mean NTpro-BNP concentration in the occult group with exclusively VPCs, no statistically significant difference was achieved in comparision to the healthy control group using Bonferroni’s equitation. The small number of only 17 dogs in this group might be a reason for the lack of statistical significance. One limitation of this study is the fact that not all dogs, especially those in the healthy control group, could be followed up to the end of their lives. Therefore, it might be possible that “still healthy” dogs with genetically determined cardiomyopathy are included in the healthy control group. As a consequence, the reference value could be falsely high. Long-term studies will be needed to validate the reference value in a group of definitively genetically healthy animals. The tendency to higher NTpro-BNP values in the still normal group also should be studied in a larger population in order to evaluate the potential of NTpro-BNP as an early marker of cardiomyopathy in Doberman Pinschers. NTpro-BNP cannot replace the Holter ECG and echocardiographic measurements in the diagnosis of occult cardiomyopathy at present. But if the time-consuming and cost-intensive methods that require a high specialization are not available, NTpro-BNP levels could indicate the necessity of referring the patient to a cardiologist. Because of the high sensitivity of 90 % for predicting abnormal echocardiographic changes, it might be possible that the measurement of NTpro-BNP eventually could replace the echocardiographic examination, but not the Holter-ECG.