Flowmetric assessment of coronary bypass grafts in the conditions of artificial circulation and on the beating heart

Bazylev V.V., Nemchenko E.V., Karnakhin V.A., Pavlov A.A., Mikulyak A.I

Federal Centre of Cardiovascular Surgery under the RF Public Health Ministry, Penza, Russia

Advantages and shortcomings of aortocoronary bypass grafting on the beating heart and in the conditions of artificial circulation (AC) have long been discussed. The data on patency of bypass grafts in the remote period are indicative of comparable results of operations with and without AC or advantages of using AC. In order to determine benefits of each method it is necessary to reveal intraoperative predictors of bypass grafts occlusion in the remote period.

We analyzed the results of ultrasound flowmetry of the blood flow through the left internal thoracic artery during bypass grafting of the anterior descending artery with the use of AC and on the beating heart. A retrospective study included a total of 352 patients subdivided into 2 groups: Group One was composed of 120 patients undergoing surgery in the conditions of AC and Group Two comprised 232 patients subjected to similar operations on the beating heart. Blood flow was measured with the help of flowmeter VeryQ MediStim^® after termination of AC and inactivation of heparin by protamine, with systolic pressure of 100-110 mm Hg.

There were no statistically significant differences between the groups by the diameter and degree of stenosis of the anterior descending artery, diameter of the left internal thoracic artery. The mean volumetric blood flow velocity (Q_mean) along the shunts in Group One was higher (p=0.01). No statistically significant differences by the pulsatility index (PI) between the groups were revealed (p=0.2).

A conclusion was drawn that coronary bypass grafting of the anterior descending artery by the left internal thoracic artery in the conditions of artificial circulation made it possible to achieve higher volumetric velocity of blood flow through the conduit as compared with operations on the beating heart, with similar resistance index. The immediate results of the operations with the use of the both techniques did not differ.

KEY WORDS: coronary bypass grafting, intraoperative ultrasound Doppler flowmetry, artificial circulation, operation on the beating heart.

P. 72

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