Policy of using the right internal thoracic artery "in situ" for coronary artery bypass grafting

Vechersky Yu.Yu., Andreev S.L., Zatolokin V.V.

Department of Cardiovascular Surgery, Research Institute of Cardiology under the Siberian Branch of the Russian Academy of Medical Sciences, Tomsk, Russia

The authors analysed the outcomes in a total of 73 patients subjected to coronary artery bypass grafting with the use of the "in situ" the right internal thoracic artery. Of these, 14 patients endured bypass grafting with assessment of the conformity of the length of the "in situ" right ITA as a conduit for the distal third of the right coronary artery (RCA). 16 patients underwent grafting of the RITA "in situ" with the RCA by passing through the pleural cavity. The remaining 43 patients were subjected to bilateral mammary composite bypass grafting using the radial artery (RA). A total of 22 segments of the RA were subjected to a comparative morphometric examination depending on the method of exposure. We additionally analysed 56 cases of utilizing the RA with the use of the pharmacological protocol of preventing spasm. The results were regarded statistically significant if p<0.05. We used the non-parametric criterion of Mann-Whitney. The obtained results showed that the right ITA "in situ" may be used for bypass grafting of the RCA system, excluding the risk of graft tension, if the perpendicular from the 6th intercostal space crosses the sharp edge of the heart 1.5-2 cm distal to the medial point, with the minimum number of complications after 1.5±0.3 years (7.1%). When the above-mentioned perpendicular is located proximal to the middle point of the sharp edge of the heart it is possible to use the right ITA "in situ" for the RCA system thanks to passing the conduit through the right pleural cavity under the anterior segment of the upper lobe and the medial segment of the middle lobe of the right lung with no complications after 1 year.

The method of composite bypass grafting by means of the proximal segment of the right ITA "in situ" and the RA makes it possible to effectively revascularize any portions of the coronary bed (latency 94.7% after 3.0±0.8 years), to avoid manipulations on the aorta, and to save the bed of the right ITA in the middle and distal third of the sternum with no postoperative complications. It was revealed that in the conditions of decreased osmotic pressure the increase in the thickness of the vascular wall is more pronounced in the skeletonized segments of the RA (1.38±0.05 mm) as compared with the segments surrounded by connective and fatty tissue (1.09±0.04 mm). The pharmacological protocol for prevention of radial artery spasm used in 56 patients resulted in a small number of complications observed after 3.0±0.8 years (myocardial infarctions – 1.75%, angina pectoris relapse – 7%). Hence, the developed methods of using the right ITA "in situ" widen possibilities of bilateral mammary bypass grafting, excluding the existing problems of routine use of the both ITAs "in situ".

KEY WORDS: coronary artery bypass grafting, bilateral mammary coronary bypass grafting, radial artery.

P. 154

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