Aortic Stenosis in Dogs and Cats: Past, Present and Future

*Aleksandra Domanjko Petrič, Anja Perovič, Tanja Švara and Peter Dovč*

#### **Abstract**

Aortic stenosis is one of the three most common congenital heart defects in dogs and less frequent in cats. Most dogs or cats have subvalvular type of stenosis; valvular or supravalvular types are less frequent. Heart failure is seldom a consequence of aortic stenosis; most dogs with heart failure have a concurrent disease. The most common accompanying diagnosis is pulmonic stenosis, especially in the Boxer breed. Screening programs seem to have efficiently lowered the incidence of aortic stenosis in dogs. Genetic evidence for aortic stenosis has been shown in Golden Retriever, Newfoundland and Dogue de Bordeaux; however, the genetic background of aortic stenosis at molecular level remains unclear.

**Keywords:** aortic stenosis, congenital heart defect, genetics, sudden death, dog, cat

#### **1. Introduction**

Aortic stenosis can be defined as a narrowing of the left ventricular outflow tract (LVOT) and/or aorta at the level below the aortic valve, at the aortic valve, or above it. This narrowing produces a blood flow turbulence that is auscultated as a systolic murmur at the heart base, as well as increased blood flow velocity that can be detected and measured by Doppler echocardiography.

Aortic stenosis is mainly considered to be a congenital defect found in many species including humans. In dogs, aortic stenosis has autosomal inheritance; however, the mode of inheritance seems to be more complex in monogenic traits.

Various forms of aortic stenosis as well as its possible genetic background have been recorded in domestic animals since the late 1960s and 1970s [1]. In those times, the final diagnosis was mostly confirmed at necropsy. Currently, diagnosis is based on echocardiographic evaluation of the morphology of the left ventricular outflow tract and aorta and the velocity of blood measured by the continuous wave (CW) Doppler method after a murmur is detected. Prognosis depends on the severity of the stenosis being from no effect on life quality and expectancy in mild forms of the disease to decreased life quality and expectancy in moderate to severe forms due to possible complications. Those include syncopal episodes that can result in sudden death, tiredness on exertion, or in rare cases, congestive heart failure or infective endocarditis [2].

The aim of this chapter is a review of the existing literature and our experience with clinical aspects of AS in dogs and cats. Genetic evidence for aortic stenosis has been shown in Golden Retriever, Newfoundland, and Dogue de Bordeaux; however, the genetic background of aortic stenosis at a molecular level remains unclear.
