The Aetiology of Pulmonary Thrombosis in Cyanotic Congenital Heart Disease with Pulmonary Stenosis

Abstract

Although a decade has passed since Rich (1948) reported the tendency of pulmonary thrombosis to develop in patients with Fallot's tetralogy, the aetiological factors concerned in this process have received little attention. He considered the classical pathological causes of thrombosis, namely anoxaemia, diminished pulmonary blood flow and increased blood viscosity, to be more important than pulmonary embolism, but he gave no physiological data to support this view. The purpose of this communication is to present the results of an investigation into the relationship between the incidence of pulmonary thrombosis and the age, pulmonary arterial blood pressure and flow, and the value for haemoglobin in 25 patients who had pulmonary stenosis and who died after cardiotomy. The operation had been preceded in most instances by physiological studies during cardiac catheterization utilizing techniques described previously (Barratt-Boyes and Wood, 1957). The present study is concerned with the cause of the thrombi and not with their characteristic form and distribution within the lung, which have been considered in seven different types of cyanotic congenital heart disease without pulmonary hypertension by Best and Heath (1958). In the course of the present investigation, we also recorded the incidence of medial hypertrophy in the muscular pulmonary arteries. METHODS AND MATERIALAs already noted, a study was made of 25 patients who had pulmonary stenosis; this lesion was isolated in two cases, whereas it was associated with a ventricular septal defect in 15 cases, with an atrial septal defect in five, and with a common ventricle, corrected transposition of the vessels with atrial septal defect, and the

The Vascular Pathology of the Lung in Congenital Malformations of the Heart with Severe Pulmonary Stenosis or Atresia and Right-to-left Shunt

“…Heath et al [15], especially, demonstrated that pulmonary thrombi are present only when the pulmo nary index (pulmonary blood flow in litres per minute per square metre of body surface) is less than 2.5. Compensatory polycythemia increases the tendency to thrombosis, by increasing blood viscosity [24,1,15], without being however an indispensable factor. Moreover, a correlation of no small practical importance has been shown between the occurrence of thrombi and the patients age [23.…”

“…This is considered the main and most effective cause of pulmonary thrombosis in congenital heart disease with pulmonary stenosis or atresia [7,22,9]. Heath et al [15], especially, demonstrated that pulmonary thrombi are present only when the pulmo nary index (pulmonary blood flow in litres per minute per square metre of body surface) is less than 2.5. Compensatory polycythemia increases the tendency to thrombosis, by increasing blood viscosity [24,1,15], without being however an indispensable factor.…”