Selection of coronary bypass. Anatomic, physiological, and angiographic considerations of vein and mammary artery grafts.

Results of direct coronary revascularization with 511 grafts in 213 patients from 1971 to 1974 are reviewed. To improve an early saphenous vein graft (SVG) patency of 84 per cent in the first 85 patients, we have used internal mammary artery grafts (IMAG), when possible, since January, 1973. In 1973 to 1974, 15 patients had SVG's only (36 grafts) and 113 received one or two IMAG's with or without additional SVG's (total 282 grafts); in 26 we used a crossed double IMAG. Forty-seven of 48 patients with unstable angina survived and did well. Flows in SVG's and IMAG's were comparable. Flows in right IMAG's to diagonal or marginal vessels were higher than in right IMAG's to right or left anterior descending (LAD) vessels. In 12 patients with both SVG and IMAG, there was no difference in flow response of either graft to vasoactive drugs. Survival, functional, and patency results with IMAG's were as good as or better than results with SVG's. We conclude that IMAG's yield higher patency and comparable flow rates to SVG's and should be used when the IMA approximates the recipient artery in size and when a high pulsatile free flow is measured from the end of the graft. IMAG's are also safe and feasible for unstable angina.     

Graft failure and recurrence of symptoms after coronary artery bypass grafting

Objectives. Saphenous vein grafts (SVGs) most often used in coronary artery bypass grafting (CABG) are subject to graft disease and have poor long-term patency, however the clinical implication of this is not completely known. We aim to assess the influence of graft failure on the postoperative recurrence of coronary artery disease (CAD) symptoms in relation to the contribution from progression of atherosclerosis in the native coronary vessels. Design. Within the SWEDEHEART registry we identified 46,663 CABG cases between 2001 and 2015 with patient age 40–80 years where single internal mammary artery (IMA) anastomosis (IMA), single IMA with one (1SVG) or multiple SVG anastomoses (2+ SVG) had been performed. Clinical characteristics as well as mortality and postoperative incidence of coronary angiography were recorded and multivariable adjusted hazard ratios were calculated. Indications for the angiographies and occurrence of graft failure were also registered. Results. The adjusted hazard ratio for death was similar for the three groups. The adjusted hazard ratio for being submitted to angiography as compared to 2+ SVG was (95% CI) 1.24 (1.06–1.46) for IMA and 1.21 (1.15–1.28) for 1SVG. Failed grafts were found at the first postoperative angiography with preceding CAD symptoms in 21.4% of patients in the IMA group, 41.6% in the 1SVG group and 61.1% in the 2+ SVG group. Conclusions. A substantial amount of angiographies occur in patients without any graft failure and a large part of postoperative recurrence of CAD symptoms and are likely attributed to IMA failure or progression of atherosclerosis in the native coronary arteries.     

Off-pump coronary artery bypass may decrease the patency of saphenous vein grafts

BACKGROUND: There is concern that a hypercoagulable status is caused after coronary artery bypass grafting without cardiopulmonary bypass (off-pump coronary artery bypass grafting, or OPCAB) and may potentially endanger the patency of the anastomosis. The aims of this study were: (1) to compare 1-year graft patency after OPCAB with that of conventional coronary artery bypass grafting (CABG) and that of on-pump beating CABG; and (2) to demonstrate any differences in patency of various conduits among the three groups. METHODS: We analyzed the results of 122 consecutive OPCAB cases (group 1) compared with those of 65 consecutive conventional CABG cases (group II) and those of 19 consecutive on-pump beating CABG cases (group III). In group I, coronary angiography (CAG) was performed immediately postoperatively and 1 year after surgery. In groups II and III, CAG was performed 1 year after surgery. Graft patency was graded as grade A (excellent), grade B (fair), or grade O (occluded). RESULTS: The average number of distal anastomoses in groups I, II, and III were 3.1 +/- 1.1, 3.7 +/- 0.9, and 3.6 +/- 0.9, respectively. In group I, postoperative CAG was performed in 92% of patients (112/122) before discharge. The patency rate (grade A + B) was 96.4% (162/168) for arterial grafts, and 85.6% (160/187) for saphenous vein grafts (SVG). One-year follow-up CAG was performed in 74% of patients (90/122). The patency rate was 97.8% (132/135) for arterial grafts and 67.9% (106/156) for SVG. In group II, 1-year follow-up CAG was performed in 65% of patients (42/65). The patency rate (grade A + B) was 93.5% (43/46) for arterial grafts and 88.3% (98/111) for SVG. In group III, 1-year follow-up CAG was performed in 89% of patients (17/19). The patency rate (grade A + B) was 100% (19/19) for arterial grafts and 86.8% (33/38) for SVG. CONCLUSIONS: Our results demonstrate that the patency rate ot SVG after OPCAB was significantly lower than that of arterial grafts in the early postoperative CAG (p < 0.001), and was also significantly lower than those of SVG of group II (p < 0.001) and group III (p < 0.01) in the postoperative 1-year CAG, although there was no significant difference in 1-year patency of arterial grafts among the three groups. Our data suggest that a specific perioperative anticoagulant therapy may be advisable in patients undergoing OPCAB with SVG.     

Comparison of postoperative complications between saphenous vein and IMA grafts to left anterior descending coronary artery

Considerable controversy exists regarding relative morbidity associated with the saphenous vein graft (SVG) and internal mammary artery (IMA) graft in patients undergoing myocardial revascularization. As a part of the cooperative study on use of antiplatelet drugs for graft patency, operative and postoperative data were prospectively collected on 1,150 patients who underwent either SVG (n = 656) or IMA anastomosis (n = 494) to the left anterior descending coronary artery. There were no differences in baseline characteristics of patients, distribution of randomization among treatment groups, and total number of distal anastomoses performed between the two groups. The aortic cross-clamp time, cardiopulmonary bypass duration, operative time, and chest tube drainage were greater (p = 0.0001) in the patients with IMA grafts compared with SVG. However, there was no difference in the operative mortality rate, the amount of blood and blood products received, the reoperation rate for control of postoperative bleeding, and incidence of wound complications between the two groups. The early and 1-year patency rates for the IMA were slightly but not significantly better than the SVG patency rates (92.8% versus 90.1% for 1-year patency; p = 0.309). In conclusion, use of IMA is associated with a longer operative time as well as increased postoperative bleeding compared with the SVG. It, however, does not increase operative mortality or postoperative morbidity.     

Coronary artery bypass grafting with combined arterial grafts

Coronary artery bypass grafting with combined arterial graft using the left internal mammary artery (IMA), right IMA, and the right gastroepiploic artery (GEA) was performed in 45 patients with saphenous vein graft (SVG) (29 patients) or without SVG (16 patients) from February 1989 to October 1989. The left IMA was used in all patients, the right IMA was used in 9 patients, and the GEA was used in 43 patients. Perioperative myocardial infarction was noted in two patients who had hospital deaths. Reopening the chest for postoperative bleeding was performed in two patients, and the cerebral accident was noted in one patient. Fourteen patients were operated on without the requirement for blood transfusion. Studied within 3 postoperative months, all arterial grafts were patent though the patency was 97.7% (43/44) in SVG. It is concluded that the combined arterial graft utilizing the IMAs and GEA can be used safely and effectively.     

Safety and efficacy of internal mammary artery grafts for left main coronary artery disease. A preliminary report

Questions regarding the relative safety and efficacy of internal mammary artery (IMA) grafts versus saphenous vein grafts (SVG) in patients with left main coronary artery disease (LMCAD) have not been specifically addressed in the literature. To elucidate this point, we analyzed 196 patients with LMCAD who underwent myocardial revascularization between January 1975 and December 1981, 98 by IMA and SVG and 98 by SVG, IMA was used most often to bypass the left anterior descending (LAD). Chi Square and "t" tests were performed on all demographic, cardiac and operative data comparing IMA to SVG. All results were non-significant, indicating that the two groups were comparable. Anginal pattern was progressive or unstable in 93%. IMA was used in 4 patients who were on intra-aortic balloon pump. The mean number bypass grafts per patient was 3.1. Postoperative complications were comparable for both groups, including early and late myocardial infarction. Overall operative mortality was 2.6%. Results of a survival analysis indicated no significant difference in the mortality rates of patients operated on by SVG versus IMA-SVG. Cumulative mortality rates at a mean followup of 20.5 months were 12.2% for SVG and 7.1% for IMA patients. Significant mortality risk factors were ejection fraction less than 55% (p less than 0.05); and perioperative myocardial infarction (p less than 0.001). Twenty-five patients with recurrent chest pain underwent repeat cardiac catheterization. This revealed 10 of 10 patent IMA grafts, 6 of 8 single patent SVG to LAD and 6 of 9 patent sequential vein grafts to the diagonal and LAD arteries.(ABSTRACT TRUNCATED AT 250 WORDS)     

Blood flow analysis of aorto-coronary bypass graft using a Doppler catheter--with special reference to comparison of SVG with IMAG

Since June to December, 1988, 46 patients had aorto-coronary bypass grafting (CABG) to the left anterior descending artery. Fifteen patients among them were subjected to this study. In 8 cases the internal mammary artery (IMAG group) was used and in 7 cases the saphenous vein graft was chosen as a bypass material (SVG group). Mean periphery anastomotic portion was 2.3 +/- 0.5 places for each group. Within two months after operation, intra-graft flow velocity was measured using a Doppler catheter. Mean cross sectional areas of the graft were 13.3 +/- 8.4 mm2 in the SVG group and 6.0 +/- 1.2 mm2 in the IMAG group. Peak flow velocity in diastole in SVG group and IMAG group were 9.9 +/- 2.7 cm/sec and 15.9 +/- 8.9 cm/sec, respectively (p less than 0.05). Also flow velocity in SVG (6.7 +/- 1.8 cm/sec) was significantly (p less than 0.05) lower than that in IMAG (12.1 +/- 6.4 cm/sec) in systole. There were no significant differences in peak, mean and integrated D/S ratio between SVG and IMAG as follows, peak D/S ratio: 1.6 +/- 0.3 in SVG, 1.4 +/- 0.4 in IMAG, mean D/S ratio: 1.5 +/- 0.3 in SVG, 1.4 +/- 0.4 in IMAG, integrated D/S ratio: 2.0 +/- 0.4 in SVG, 2.7 +/- 0.9 in IMAG. It is concluded that no significant differences were demonstrated between SVG and IMAG as to the intra-graft flow velocity profile at least in 2 months after operation.     

Early and lage results of coronary revascularization with saphenous vein and internal mammary artery grafts.

Five hundred forty-seven consecutive coronary revascularizations for anginal syndromes and 72 combined with other procedures (valve replacement, myocardial resection, closure of septal rupture) were performed during a five year period beginning in January 1972. The 619 patients received 1,794 grafts; 208 had one or two internal mammary artery grafts (IMAG) into anterior coronary arteries with or without additional saphenous vein grafts (SVG), and 411 had SVGs only. A 99.5 per cent follow-up of eighteen to seventy-eight months (mean, 50 months) allows a balanced view of the merits and shortcomings of each conduit and an evaluation of long-term surgical results.Hospital mortality of 3.3 per cent (13 of 547) in revascularization alone included 9 deaths in 402 patients (2.2 per cent) with stable angina, 4 in 134 (3.0 per cent) with unstable angina, and 5 in 11 (45.0 per cent) with cardiogenic shock. Mortality and morbidity were similar with or without IMAGs. IMAG and SVG flows measured at operation were comparable, but one year patency was 97 per cent and 86 per cent, respectively (p < 0.05). Late occlusion (3 per cent) or “distal thread” stenosis (2 per cent) occurred only in those with small IMAGs, especially when the coronary lesion was only moderately severe. Graft occlusion and recurrence of symptoms required reoperation in five SVG and two IMAG patients. Actuarial survival was 95 per cent at one year, 93 per cent at three years, and 92 per cent at five years. Ninety-five per cent of the survivors improved one functional class (FC) or more, and 85 per cent are asymptomatic, with a higher proportion in IMAG patients. Eighty-two per cent of those less than age sixty years resumed gainful employment. Hospital mortality was higher for those with combined procedures, especially with infarctectomy and/or closure of septal rupture. Zero mortality occurred in the last two years in those with revascularization and valve replacement, perhaps related to cold cardioplegic myocardial protection.Coronary revascularization provides excellent long-term functional results. Survival in the entire group, including patients with unstable angina and those with cardiogenic shock, is significantly better than survival of patients with stable angina recently reported by the Veterans Administration Cooperative Study. A 10 per cent better long-term patency rate with an IMAG is particularly important in muscular young individuals with stable hemodynamics. Its use is not warranted in unstable patients, in patients with combined procedures, and in patients with massive left ventricular hypertrophy.     

Clinical results, graft patency and flow reserve capacity of multiple coronary artery bypass with bilateral or sequential internal thoracic artery grafts

Multiple coronary artery bypass grafting (CABG) was performed utilizing the internal thoracic arteries (ITA) in 87 patients ranging in age from 3 to 76 years. Bilateral ITAs were used in 67, sequential grafting was performed in 16, and the combination of both techniques was applied in 4 patients. Twelve patients had coronary arterial obstructions due to Kawasaki disease (mean age 9.7 +/- 3.3 years) and the remaining 75 patients had atherosclerotic coronary artery disease (mean age 53 +/- 10 years). Triple vessel disease and left main trunk disease occupied 85% of the patients. The number of grafts was 2 to 5 per patient with an average of 3.2 +/- 0.7 per patient. In bilateral ITA grafting, the combination of the RITA to LAD and LITA to LCX was most frequently used, and in sequential grafting, the LITA-diagonal artery-LAD was the most common use. There were no early or late mortalities in the present series. The patency rates for the RITA and LITA were 93% and 96%, respectively, and those of sequential grafting were 100% in both the proximal and distal anastomoses. The clinical outcome of multiple CABG with ITAs was quite satisfactory, and the bilateral ITAs could be used in the very wide range of patient's age from 3 to 76 years. In addition, blood flow reserve provided by bilateral ITAs was equivalent to that of the SVG alone or SVG plus ITA on the basis of the result of coronary sinus flow (CSF) measurements during exercise, and thus complete revascularization of the left ventricle could be accomplished by multiple CABG with ITAs.     

Utility and limitation of sequential saphenous vein graft for complete revascularization in coronary artery surgery

Multiple bypass grafting in complete myocardial revascularization requires frequently the use of sequential saphenous vein grafts as well as arterial grafts. To expect the favorable good clinical results of revascularization, therefore, refined surgical technique for saphenous vein grafting and proper selection of suitable coronary arteries for bypass are important. Between January 1989 and April 1990, 91 patients underwent CABG utilizing internal thoracic arteries (ITA) in 79% and SVG in 99% of the patients with an average of 3.3 anastomoses per patients. Postoperative angiography was performed 4 or 8 weeks after surgery. Early patency rates were 92% (204/221) in overall anastomotic sites, 96% (52/54) in ITA and 91% (152/167) in SVG respectively. There was no difference in patency rates between individual (90%) and sequential (92%) grafts. In sequential grafting, however, patency rate of side-to-side anastomosis was higher than that of end-to-side anastomosis. Patency rates of the grafts were also evaluated in terms of the sizes of coronary arteries and intraoperative graft flows. These studies lead to the following conclusions: In individual grafting, the acceptable patency rate can be expected when the graft flow exceeds 30 ml/min even if the internal diameter of coronary artery is less than 1.5 mm. In sequential grafting, on the other hand, a diameter more than 1.5 mm is desirable for the coronary artery at the site of end-to-side anastomosis.     

Evaluation of aortocoronary bypass operation using a He-Ne laser flowmeter--comparison between internal mammary artery grafts and saphenous vein grafts

It was very difficult to measure myocardial blood flow in clinical cases. Recently, a He-Ne laser doppler flowmeter was developed, and we made it possible to measure the pre-and post-operative myocardial blood flow in cases of coronary artery bypass grafting (CABG). We applied a laser flowmeter to 30 cases of bypass grafting to the left anterior descending coronary artery (18 cases with IMAG and 12 cases with SVG). The preoperative myocardial blood flow at the right ventricular anterior wall was 77 +/- 15 ml/min/100 gr, and the postoperative flow at the same point was 81 +/- 12 ml/min/100 gr. There was no significant change between the pre-operative value and the postoperative one. Myocardial blood flow at the left ventricular anterior wall in SVG group significantly increased from the preoperative value of 58 +/- 11 ml/min/100 gr to the postoperative value of 86 +/- 9 ml/min/100 gr (p less than 0.001). In IMAG group, myocardial blood flow at the left ventricular anterior wall similarly increased from 73 +/- 14 ml/min/100 gr to 83 +/- 15 ml/min/100 gr (p less than 0.01). The postoperative value of IMAG group was almost equal to the value of SVG group. The increased rate of myocardial blood flow at the left ventricular anterior wall was 52 +/- 32% in SVG group and 18 +/- 12% in IMAG group. These rates were obviously distinguished from the increased rate at the right ventricular anterior wall.(ABSTRACT TRUNCATED AT 250 WORDS)     

The correlation between flow pattern during cardiopulmonary bypass and patency of the coronary artery bypass grafts

Recently the availability of transit time flow measurement (TTFM) is reported especially in off-pump coronary artery bypass grafting (CABG). But little is known about TTFM findings in on-pump CABG. We examined the correlation between the TTFM flow pattern and the angiography findings in on-pump CABG. The subjects consisted of 52 patients who underwent on-pump CABG and angiography early after operation. In these patients, 55 internal thoracic artery (ITA), 17 gastroepiploic artery (GEA), 13 saphenous vein graft (SVG) and 41 radial artery (RA) were tested with TTFM during cardiopulmonary bypass (CPB). TTFM demonstrated a diastolic filling pattern in 53 ITA, 16 GEA, 13 SVG and 36 RA. The angiography revealed that all these grafts were perfectly patent with the exception of a GEA with a flow competition pattern. TTFM revealed an abnormal flow pattern in 2 ITA (these 2 grafts were revised during CPB and the angiography demonstrated their perfect patency), 1 GEA (to and fro pattern), 0 SVG and 5 RA (the abnormal pattern was due to graft spasm in 3 of 5, and the angiography revealed their perfect patency, however, the angiography detected stenosis in the remaining 2 grafts). The present study found that the TTFM flow pattern during CPB correlated well with the angiography findings. TTFM during CPB was useful to detect graft failure, and grafts were revised safely during CPB.     

Internal mammary artery bypass grafting: influence on recurrent angina and survival in 2,100 patients

Internal mammary artery (IMA) bypass grafting to the anterior descending coronary artery was performed in 2,100 patients between January 1978 and July 1986. The average number of additional saphenous vein grafts (SVGs) per patient was 1.8. During the same period, 1,753 patients underwent coronary artery bypass grafting using an SVG (average number of grafts per patient, 3.2). The average patient age was similar: 62.3 years for IMA grafts and 64.7 years for SVGs. Men constituted two thirds of each group. Left ventricular function was impaired (ejection fraction less than 45%) in 1,071 (51%) of IMA grafts and 847 (48.3%) of SVGs. Other aggregate risk factors, ie, elevated blood pressure, diabetes mellitus, previous myocardial infarction, and congestive heart failure, were similar in each group. Operative results and postoperative mortality of the IMA and SVG patients were comparable. However, the long-term probability of cumulative survival and occlusion-free survival were significantly greater and the probability of recurrent angina and reoperative coronary artery bypass grafting were significantly less in IMA graft patients (p less than 0.015). The relative risk of occlusion in an SVG was 4 to 5 times greater than that of the IMA graft. These data indicate that a patent IMA graft to the anterior descending coronary artery protects against recurrent angina and death from cardiac-related causes, and that the IMA should be the conduit of choice.     

Coronary Artery Grafting with the Saphenous Vein or Internal Mammary Artery: Comparison of Late Results in Two Consecutive Series of Patients

In two series of consecutive patients who underwent coronary artery grafting with the saphenous vein or the internal mammary artery (IMA), angiographic studies were conducted two weeks and one year after operation. The early patency rate was 91.8% in 184 vein grafts and 97.4% in 38 IMA grafts. Late patency was 93.1% in 143 vein grafts and 90.9% in 33 IMA grafts. Thus, the cumulative patency rate at one year was 84.9% for vein grafts and 88.3% for IMA grafts.The incidence of severe narrowing at the site of anastomosis was 2.2% in vein grafts and 7.9% in IMA grafts; the rate of occlusion of the distal limb of the recipient coronary artery was, respectively, 4.3 and 7.9%. Diffuse reduction in the caliber of grafts at one year was less frequent with IMA grafts (12.7 versus 6.6%). On the other hand, blood flow was significantly higher in vein grafts: 67.4 versus 45.2 ml per minute (p < 0.001). Blood flow in IMA grafts whose caliber was larger than that of the recipient coronary artery was significantly higher than flow in IMA grafts with a caliber equal or inferior to that of the coronary artery: 63.1 versus 32.7 ml per minute (p < 0.001).Although cumulative patency rates at one year were comparable in both series, because only one-third of the IMAs were larger than their recipient coronary arteries, flow was somewhat restricted in the other two-thirds. This suggests that the IMA does not constitute the better bypass conduit and, unless it is of large caliber, preferably should be used in the grafting of small coronary arteries or those with limited runoff.     

Internal mammary artery grafts: technical factors influencing patency

Eight hundred fourteen patients with internal mammary artery (IMA) coronary artery bypass grafts have been restudied 961 times with coronary arteriography, primarily to evaluate the patency of the grafts in the setting of symptomatic coronary occlusive disease. Their records were reviewed to assess graft patency as related to the technical aspects of coronary artery bypass surgery. Patency was evaluated using life-table analysis of the data. The method of harvesting the IMA played no role in patency. The left anterior descending coronary artery was the recipient coronary artery with the highest patency rate. The left IMA had a significantly higher patency rate than the right IMA. As a group, the IMAs had a significantly higher patency rate than saphenous vein grafts. However, there was no difference between right IMA grafts and saphenous vein grafts. The mammary artery grafts that remained patent throughout the study had a significantly higher blood flow after bypass than did those that became occluded (43.0 +/- 0.9 versus 28.9 +/- 1.8 ml/min; p less than .001).     

70岁以上冠状动脉旁路移植术病人乳内动脉流量测量分析

目的 分析70岁以上冠状动脉旁路移植术病人乳内动脉旁路血管血流量的特点.方法 对2003年1月至2007年1月间78例70岁以上(含70岁)应用乳内动脉非体外循环冠状动脉旁路移植手术(OPCAB)的病人,使用瞬时超声血流测量技术对其乳内动脉平均血流量、搏动指数等指标进行测量并分析.结果 78例病人83根乳内动脉旁路血管平均流量(36.0±21.5)ml/min,平均搏动指数3.50±1.76,血流波形均以舒张期为主.男女性别比、平均流量和搏动指数差异无统计学意义[(39.0±23.1) ml/min对(28.0±14.7) ml/min;(3.30±1.50)对(4.10±2.22),P>0.05],但女病人平均流量较男病人偏低,搏动指数较男病人偏高.结论 70岁以上病人冠状动脉旁路移植术应用乳内动脉是安全、有效的;对老年病人乳内动脉流量的评价分析应当结合老年病人的病变特点.     

Detection of coronary artery bypass graft patency by contrast enhanced magnetic resonance angiography.

OBJECTIVE: The subject and purpose of the prospective study was to delineate coronary artery bypass graft (CABG) course and to determine patency of aortocoronary venous bypass grafts (ACVB) compared with internal mammary artery bypass grafts (IMA) in the early postoperative follow-up, by contrast enhanced magnetic resonance angiography (MRA). For control, patients were examined with X-ray angiography and spiral-computed tomography (CT). METHODS: Eighty-five patients (74 male/11 female) with a mean age of 63.7 years underwent MRA examination, applying contrast enhanced gradient-echo sequence after an average distance of 7 days from CABG surgery. A 1.5 Tesla magnetom vision (Siemens, Erlangen, Germany) with phased array coil technology was used. Overall, 247 bypass grafts (160 ACVB/87 IMA) were studied with a 3D (three dimensional) ultrashort TE gradient-echo sequence (TR/TE/a:5 ms/2 ms/40 degrees) with 512*512 matrix and 500 mm FoV in single breath-hold technique after Gd-DTPA bolus injection. CABGs were judged in three different parts, including the course of CABG and both anastomoses. CABGs were controlled by angiography and spiral-CT to examine sensitivity, specificity and efficiency of MRA examination. Additional measurement of bypass graft flow velocity of arterial and venous grafts was performed with 2D phase contrast technique in breath-hold technique with ECG triggering. RESULTS: One hundred and thirty-nine of 160 (86.9%) ACVB grafts and 83 of 87 (95.4%) IMA grafts could be visualized. Suspected occlusions of 10 CABGs were confirmed in 80% with a second modality. Five CABGs were false positive in MRA. MRA proved a high specificity (93.8%), sensitivity (89.9%) and efficiency (1.73), especially in detection of IMA to LAD and ACVB to LAD and RCA (Table 1). 3D maximum intensity projection (MIP) reconstruction was helpful in delineating CABG course and in several cases in detecting stenosis of coronary arteries. Results of flow velocity showed a significant higher mean systolic velocity in arterial bypasses than in venous grafts with a higher maximum velocity in systole than in diastole in both grafts. Bypass stenosis in distal anastomosis could not be verified with MRA and flow method. CONCLUSION: Contrast enhanced 3D ultrashort TE gradient-echo magnetic resonance angiography has the potential for being a reliable method for CABG visualization and CABG patency determination in the early postoperative period. MR flow measurement was not qualified for detection of a bypass stenosis.     

Mediastinitis after coronary artery bypass grafting increases the incidence of left internal mammary artery obstruction

Mediastinitis after coronary artery bypass grafting (CABG) gives a longstanding chronic inflammation and has a detrimental negative effect on long‐term survival. For this reason, we aimed to study the effect of mediastinitis on graft patency after CABG. The epidemiologic design was of an exposed (mediastinitis, n = 41) versus non‐exposed (non‐mediastinitis, controls, n = 41) cohort with two endpoints: (i) obstruction of saphenous vein grafts (SVG) and (ii) obstruction of the internal mammary artery (IMA) grafts. The graft patency was evaluated with coronary CT‐angiography examination at a median follow‐up of 2·7 years. The number of occluded SVG in the mediastinitis group was 18·9% versus 15·5% in the control group. Using generalized estimating equations model with exchangeable matrix, and confounding effect of ischaemic time and patients age, we found no significant association between presence of mediastinitis and SVG obstruction [rate ratio (RR) = 0·96, 95% CI (0·52–2·67), P = 0·697]. The number of occluded IMA grafts was 10·5% in the mediastinitis group and 2·4% in the control group. Using the Poisson regression model, we estimated RR = 5·48, 95% CI (1·43–21·0) and P = 0·013. There was a significant association between mediastinitis and IMA graft obstruction, when controlling for the confounding effect of ischaemic time, body mass index, presence of diabetes mellitus and the number of diseased vessels. Presence of mediastinitis increases the risk of IMA graft obstruction. This may confirm the importance of inflammation as a major contributor to the pathogenesis of atherosclerosis and explain the negative effect of mediastinitis on a long‐term survival.     

Nonreversed saphenous vein grafts for coronary artery bypass grafting

Between August 1985 and December 1988, valvotomized saphenous vein grafts were used in 365 patients undergoing coronary artery bypass grafting (CABG). In this operation, the femoral end of the vein is attached to the aorta and the pedal end is attached to the coronary artery. Vein diameters measured 8 +/- 2 mm at the femoral end, 4.5 +/- 1.2 mm at the knee level, and 3.5 +/- 1.3 mm at the ankle. Ratios between levels were as follows: knee to femoral end, 0.56, and ankle to femoral end, 0.43. The ratio of knee to femoral end was 0.42 in cases with vein midthigh bifurcation. There were 1,310 grafts implanted (3.6 per patient). In 341 patients, CABG alone was performed, and 24 patients had combined procedures: 11 had CABG with mitral valve replacement, 9 had CABG with aortic valve replacement, 2 had CABG with repair of postinfarct ventricular septal defect, and 2 had CABG with automatic defibrillator implantation. Follow-up (up to 3.5 years) was attained in 97% of patients. For various reasons, 34 patients had a second angiogram between 3 and 41 months postoperatively. Of 120 vein grafts, 108 (90%) were patent. At autopsy, 11 patients with 45 vein grafts had 43 patent and clean grafts and two thrombosed. Use of nonreversed saphenous vein for coronary bypass is recommended. It assures a large proximal anastomosis, natural vein bifurcations can be used with fewer proximal anastomoses, better vein-coronary artery size matching is obtained, and the patency rate is satisfactory.     

Mid-term angiographic comparison of sequential and individual anastomosis techniques for diagonal artery

OBJECTIVE: The mid-term patency rates for individual and sequential grafts as coronary bypass conduits for diagonal arteries were angiographically compared; the impact of native coronary vessel and type of the conduit characteristics are investigated. METHODS: Between March 1992 and April 2000, we performed a total number of 811 distal anastomosis on diagonal arteries of left anterior descending (LAD) artery in 296 patients who underwent coronary artery bypass surgery (CABG) distal anastomosis in our clinic. The patients were divided into two groups in this prospective study. In group A (n = 195) individual anastomosis technique, in group B (n = 101) sequential anastomosis technique was chosen as the myocardial revascularization strategy. At an average of 49.4 +/- 13.2 months after coronary revascularization procedure coronary angiographies were evaluated. Individual and sequential grafting techniques were compared by graft patency rates. RESULTS: The patency rates of sequential conduits were markedly higher than those of individual conduits (66.7% vs. 89.2%, p = 0.0001). This difference was also clear in coronary arteries with poor quality and small (<1.5 mm) diameter (49.1% vs. 66.6%, p = 0.032). Also, the patency rates of sequential radial artery conduits were higher than sequential saphenous vein graft (SVG) conduits (sequential radial artery; 94.1%, sequential SVG; 85.3%, p = 0.043). CONCLUSIONS: Sequential grafting for diagonal artery is technically more demanding but the mid-term results are better than individual grafting especially in coronary arteries with poor quality. Using radial artery as a sequential graft increases the mid-term graft patency rates.