Objective To evaluate the outcome and explore the mechanism of coronary vein bypass grafting （CVBG） performed by anastomosing the right internal mammary artery with the middle cardiac vein via off-pump surgery. Methods Twelve Chinese experimental miniswines （either male or female, age from 7 to 10 months, body weight 40±5 kg） with severely diffuse stenosis in the right coronary artery were randomly divided into control group and experiment group with 6 miniswines in each group, using a random number table method. CVBG was performed in the experiment group and sham surgery was performed in the control group. To assess cardiac function, graft flow, graft patency and micro-circulation reperfusion of ischemia myocardium, following measurements were conducted. Eight weeks after right coronary endarterectomy, transthoracic echocardiography was performed for both groups. Coronary angiography, graft flow and echocardiography were performed or measured 6 hours and 3 months after CVBG or sham surgery. Measurement of myocardial blood flow with non-radioactive colored microspheres was also conducted 3 months after surgery for two groups. Results There was no statistical difference in cardiac function 8 weeks after right coronary endarterectomy between the two groups. There were significant improvements in cardiac systolic and diastolic function （ejection fraction 3 months after operation: 52%±6% vs. 44%±5%, t=-2.500, P=0.031） in the experiment group after CVBG compared with the control group. Graft flow of the experiment group 6 hours and 3 months after CVBG were 44.50±5.86 ml/min and 43.33±5.01ml/min respectively （P=0.718）, and pulsatility index （PI） was 0.73±0.14 and 0.80±0.14 respectively（P=0.858）. Internal mammary artery grafts and the anastomoses were all patent without stenosis, documented by coronary artery angiography for the experiment group 6 hours and 3 months after CVBG. Myocardial flow in all aspects especially in the subendocardial layer, estimated by non-radioactive colored microsphere injection, was significantly higher in the experiment group after CVBG than that of the control group, transmural flow was 0.33±0.05ml/（g • min） vs. 0.19±0.03 ml/（g • min） （P＜0.05）. Conclusion Ischemic conditions of the myocardium can be relieved by CVBG using internal mammary artery in a short-term to medium-term period. The mechanism may be due to improvement of the myocardial micro-circulation.
Abstract: Objective To evaluate the clinical efficacy of sequential bilateral internal mammary artery grafting combined with selective coronary venous bypass graft (CVBG) during offpump coronary artery bypass surgery. Methods We retrospectively analyzed the clinical data of 38 patients with diffuse right coronary arteriostenosis undergoing operation in Anzhen Hospital of Capital Medical University from March 2004 to August 2010. Based on the operation method, the patients were divided into two groups. In the CVBG group, there were 17 patients including 11 males and 6 females with an average age of 46.1±6.2 years who underwent off-pump sequential bilateral internal mammary artery grafting combined with CVBG. In the control group, there were 21 patients including 14 males and 7 females with an average age of 45.9±5.7 years, and they underwent the off-pump sequential bilateral internal mammary artery grafting without CVBG. Blood flow of bridged vessels was measured. The perioperative parameters including number of grafts, tracheal intubation time, hospitalization time, complications, results of echocardiography, myocardial nuclide imaging and coronary angiography were compared between the two groups of patients. Results There was no hospital mortality or complications such as cerebral events, sternal and mediastinal infections. There was statistical difference in graft number between CVBG group and control group (3.3±1.1 vessels vs. 2.2±1.6 vessels, Plt;0.05). There were no statistical differences in internal mammary artery trunk blood flow (81.5±32.7 ml/min vs. 76.8±28.4 ml/min), left internal mammary artery trunk blood flow (32.5±18.8 ml/min vs. 28.1±167 ml/min) and right internal mammary artery trunk blood flow (39.6 ±19.0 ml/min vs. 35.9±18.3 ml/min) between CVBG and control group (Pgt;0.05). Followup was done for all the 38 patients with a follow-up rate of 100%. Follow-up time was 3.55 months (37.4±9.8 months). No angina symptoms occurred in CVBG group and myocardial blood supply of inferior wall in this groups improved obviously based on the results of electrocardiogram, while there were 8 cases of angina in the control group with inferior wall myocardial ischemia and ST-T changes according to the results of electrocardiogram (Plt;0.05). Heart functions were significantly improved in both groups three months after surgery. Through myocardial nuclide imaging, we found that myocardial blood supply of inferior wall was obviously improved in CVBG group. Coronary angiography in CVBG group showed that there was blood flow to myocardium in the arterialized vein. Conclusion Sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system can be performed during offpump coronary artery bypass surgery. Cardiac functions and quality of life are improved after the surgery. This provides a new surgical method for diffuse right coronary lesions.
Objective To study the method to inhibit perioperative internal mammary artery (IMA) spasm from the perspective of muscarinic receptor, and research the function of muscarinic cholinergic receptor subtypes of IMA. Methods IMA segments in vitro with intact endothelium were obtained from 30 patients who underwent coronary artery bypass grafting (CABG). According to muscarinic receptor antagonists of different concentrations， They were divided into control group (not using receptor antagonist), atropine group (nonselective M receptor antagonist), pirenzepine group (M1 receptor antagonist) and Methoctramine group(M2 receptor antagonist) by random number table. The effects of antagonists on vasodilatation were analyzed, Scott ratio was used to calculate affinity index (pD2) and Schild plot was used to count rivalry index (pA2). Results Acetylcholine (Ach)induced concentrationdependentrelaxation response of IMA segments with intact endothelium precontracted with potassium chloride (KCl). The pD2 was 6.92±0.05. The effects of atropine, pirenzepine and methoctramine on doseresponse curve induced by Ach with intact endothelium were all concentrationdependent. With the increase of the concentration of antagonists, the Achinduced doseresponse curves had a significant shift to right(Plt;0.05). Atropine, pirenzepine and Methoctramine competitively antagonized the reaction of vessel to Ach. The pA2 were 9.62±0.15,7.70±0.08 and 630±0.08, respectively. Conclusion The Achinduced relaxation response of IMA with intact endothelium is concentrationdependent. According to the affinity of different antagonist, IMA in Vitro Achinduced relaxation response is implemented by acting on nonneuronal muscarinic cholinergic M1 receptor subtype.
Objective To analyze the mean flow in left internal m am mary artery ( L IMA) graft and the influencing factors in off- pump coronary artery bypass grafting ( OPCAB) in the Chinese. Methods One hundred and eighty patients with OPCAB were studied.Transit- tim e flowmeter( TTFM) was utilized to measure and record the L IMA’s blood flow wave,pulsatility index( PI) ,value of mean flow,systolic and diastolic peak flow,vascular resistance,insufficiency ratio and mean blood pressure and to analyze the relationship between mean flow of LIMA and other factors. Results Total mean flow calculated from that of all patients was2 8.19± 2 .89ml/ min( 6 - 178 ml/ m in) .Majority m ean value ( 6 4 .4 % ) was in the range of 10 - 30 ml/ min.Statistics showed that mean flow was significantly related to systolic and diastolic peak flow and vascular resistance rather than the other factors( r=0 .75 , 0 .94 ,- 0 .95 ) . Conclusions For the Chinese,over 10 ml/ min mean flow of L IMA graftis acceptable and ov...更多er 2 2 ml/ min is satisfactory.The diastolic peak flow and vascular resistance are two most important factors in influencing mean flow.
Objective\ To search for suitable and multiple arterial grafts for myocardial revascularization, in order to avoid the long term problems of vein graft atherosclerosis. Methods\ Between October 1994 and April 2000, 456 consecutive patients underwent myocardial revascularization using radial artery and internal mammary artery. In coronary artery bypass grafting, minimally traumatic harvesting radial artery techniques and new pharmacologic antispasmodic agents was used. Results\ 448 internal mammary artery ...
ObjectiveTo investigate the feasibility and effectiveness of using ultrasound to evaluate the internal mammary artery (IMA) and explore the related factors affecting the quality of IMA.MethodsFrom July 2020 to January 2021, for patients who underwent coronary artery bypass grafting at the Department of Cardiovascular Surgery, Fuwai Hospital, ultrasound was applied to measure bilateral IMA at the parasternal second intercostal space. There were 62 males and 18 females with an average age of 59.9±8.3 years. The clinical data of the patients were recorded and analyzed.ResultsA total of 160 IMA were measured. The IMA was detected in 99.4% (159/160), and the one that was not measured was proved to be occluded by enhanced CT. A total of 157 (98.1%) IMA intima were smooth, 2 (1.3%) were found to have uneven intimal thickening and less smooth, and only 1 (0.6%) was occluded. The intravascular diameter, peak systolic flow rate, peak diastolic flow rate, and blood flow rate of the left second intercostal IMA were 1.9±0.3 mm, 66.8±17.7 cm/s, 6.4 (0.0, 9.7) cm/s, 19.7±9.4 mL/min; and those of the right one were 2.1±0.3 mm, 69.7±18.5 cm/s, 6.0 (0.0, 9.2) cm/s and 22.8±11.5 mL/min, respectively. IMA vessel diameter and blood flow were greater on the right than those on the left side in the same individual (P<0.01). In univariate analysis, sex and body surface area were the factors that influenced the size of the IMA vessel among different individuals, and by linear regression analysis, the size of the IMA vessel was only related to body surface area among different individuals. On univariate analysis, diabetes mellitus was the only factor affecting IMA blood flow, with a mean reduction in blood flow of 18.4% (left) and 21.7% (right) in the diabetic group (P<0.05).ConclusionPreoperative evaluation of the IMA using ultrasound over the parasternal second intercostal space is easy, noninvasive, and has a high success rate. The internal diameter of the IMA is positively correlated with body surface area, and blood flow is significantly reduced in patients with diabetes.