[Functional significance of collateral coronary circulation in univascular obstructions (1)]

The presence, degree and functional significance of the coronary collateral circulation was investigated in a group of 68 patients with angiographycally important (greater than 60%) univascular coronary obstruction. The following clinical parameters were reviewed. Smoking, hypertension, diabetes mellitus, functional class (NYHA), and degree of angina pectoris. In the ECG the presence of abnormal Q waves and the response to the stress test were analysed. To evaluate the functional significance of the collateral circulation the following angiographic and hemodynamic parameters were measured: ejection fraction (FE 100), mid sistolic ejection fraction (FE 50), percent of regional shortening of the left ventricular wall and finally the end diastolic pressure. According to the obstructed vessel (R, DA, Cx) the degree of obstruction (parcial or complete) and the degree of collateral circulation (O, I, II, III) several groups were formed. Statistical analysis of all the above mentioned clinical, electrocardiographic and angiographic findings were compared amongst the various groups. Coronary collateral circulation was demonstrated in 45 patients (68%) being present in 82% of those with complete coronary obstruction. In most of the patients (87%) an abundant collateral network was present (grade II or III). No statistical differences were demonstrated between the groups with abundant or poor collateral circulation in all the clinical, electrocardiographic or angiographic parameters. Finally we conclude that important collateral circulation usually develops in the presence of severe coronary obstruction; however its functional value is limited.