Experimental aortic coarctation in puppies

Coarctation was produced in nine puppies at the age of 2 months with a simple silk ligature on the thoracic aorta. The constriction was standardized by measuring the blood pressure below the coarctation. Two of the operated puppies died. Five puppies were sham operated and they served as a control group. The blood pressure was followed by an indirect ultrasound method. At the end of 7 months of follow-up, when the dogs were 9 months old, the mean blood pressures were $\text{112}\text{76}$ mm Hg in the control group and $\text{193}\text{121}$ mm Hg in the coarctation group. The difference between the groups was highly significant (P < 0.001). A good collateral circulation could be demonstrated in the coarctation group by aortic angiography and it was also demonstrated in the measurements of renal perfusion with an isotope technique. It is suggested that experimental work involving coarctation should be performed in young animals which will develop good collateral circulation during their growth.