Changes of the internal diameter of coronary artery bypass grafts in the postoperative course: Assessment based on X-ray computed tomography

The authors used x-ray computed tomography (x-ray CT) for following up the changes of the internal diameter of coronary artery bypass grafts. After the level of the bifurcation of the truncus pulmonalis had been detected by localizing scans from the ascending aorta to the apex of the left ventricle (scanning time, three seconds; slice thickness, 5 mm) 30 mL of contrast medium was injected at a rate of 3 mL/sec via the antecubital vein. Five scans were obtained consecutively, starting eight seconds after initiation of the contrast medium injection. On the basis of two x-ray CT scans (for ± six and thirty-six ± twenty months after surgery) and a selective graft angiogram (twelve ± fifteen months after surgery), 21 patients (20 men, mean age fifty-five ± eight years) were included with a total of 35 saphenous vein grafts. The findings were compared with intraoperative electromagnetic flow meter measurements. Results: The mean internal diameter of the 28 grafts that were patent at the time of the late x-ray CT was 4.9±1.9 mm. This was significantly (P<0.01) smaller than the mean internal diameter at the time of the early x-ray CT (5.9±1.9 mm). The internal diameter of 18 grafts had decreased, 8 had remained unchanged, and 2 had increased. A significant correlation between the graft flow rate and the internal diameter did not exist. All 7 grafts that were occluded at the time of the late scans could not be visualized in any slice of the nonenhanced or of the contrast-enhanced x-ray CT. Conclusions: The internal diameter of grafts frequently decreases in the late postoperative period and shows no significant correlation with the graft flow rate. Occluded grafts cannot be visualized by x-ray CT. Presented in part at the 34th Annual Congress of the International College of Angiology, Budapest, Hungary, July 1992.     

Effects of postoperative pericardial effusion on coronary artery bypass grafts: A study with X-ray computed tomography

The aim of this study was to evaluate the effects of pericardial effusion on coronary artery bypass grafts and their patency using X-ray computed tomography (CT). Uncontrasted CT of horizontal sections from the lower margin of the aortic arch to the left ventricle was done at 5-mm intervals. In one cross-section of the pulmonary bifurcation level, 30 ml of a contrast media (lohexol 350) was injected at a rate of 3 ml/second into the antecubital vein. All slices of uncontrasted CT were analyzed for the presence or absence of effusion. The severity was expressed as the maximum value of the thickness of effusion. CT was repeated about every 6 months postoperatively under the same conditions. Selective angiography was also performed 7.1±3.9 months postoperatively. A total of 46 patients (mean age 57 years) underwent CT and angiography. A total of 95 grafts were implanted: 90 saphenous veins and 5 internal thoracic arteries. Selective angiography revealed that 79 grafts were patent and 16 were occluded. The first postoperative CT (at 2.6±2.1 months) showed the retention of effusion in all patients. The mean maximum value was 1.0±0.5 cm; there were no significant differences between patent grafts (1.0±0.5 cm) and occluded grafts (1.0±0.5 cm). Occlusion was found in 10 grafts by the first CT (2.9±2.7 months postoperatively) and another 6 grafts by the second CT (11.3±4.2 months). Thereafter, all grafts were patent. Previously occluded grafts showed no cross-section images on uncontrasted or contrasted CT. Except for two grafts, all patent grafts could be observed even without contrast enhancement. The remaining two grafts were masked with effusion, but patency was confirmed by a contrast media. In conclusion, retention of effusion does not affect the patency of grafts. Occlusion occurs early after surgery, and grafts cannot be imaged on CT. Patent grafts can be observed by uncontrasted CT, as well as contrasted CT, except where a large amount of effusion is present.Presented at the 38th Annual Congress of the International College of Angiology, Cologne, Germany, June 1996.     

Are metallic markers necessary for coronary artery bypass grafts? A study using X-ray computed tomography and selective graft angiography

Using X-ray computed tomography (CT) and selective graft angiography, the authors studied the necessity of metallic markers in coronary artery bypass grafts on 45 patients (mean age 57.2 years) with 87 saphenous vein grafts. Eight patients had 17 markers. X-ray CT was performed after surgery using an apparatus with a 1-second scanning time. Noncontrast X-ray CT was performed on horizontal sections, at 5-mm intervals, from the lower margin of the aortic arch to the lower left ventricle. A contrast medium was then injected into the antecubital vein (3 ml/second, total 30 ml) in one cross-section at the level of bifurcation of the pulmonary artery. Aortography (60° in the left anterior and oblique positions, 20 ml/second, total 40 ml) was performed concurrently. Selective graft angiography was taken in the same direction, using 4 cm right of the Judkins with reference to the aortographic image and position of five clips on the sternum. Aortography revealed 79 patent and 8 occluded grafts. Selective graft angiography was easily performed even in grafts without markers. A cross-section of the occulded graft could not be seen with X-ray CT. Grafts with markers were often masked by artifacts produced by markers on X-ray CT. The number of observed graft slices (marker-positive grafts) was only 1.2±1.1 slices, significantly (p<0.01) lower than marker-negative grafts (4.1±3.1 slices). In particular, the number of marker-positive right coronary artery grafts was 0.4±0.9 slices. Four of five right coronary artery grafts were unobservable due to artifacts. In grafts without markers, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of X-ray CT to graft patency were 100%, 85.7%, 98.4%, 100%, and 98.6%, respectively. This study suggests that metallic markers may not be necessary for coronary artery bypass grafts.A working version of this report was presented at the 39th Annual Congress of the International College of Angiology, Istanbul, Turkey, June 1997     

Non-selective intra-arterial digital subtraction angiography for the assessment of coronary artery bypass grafts

Non-selective intra-arterial digital subtraction angiography (DSA) was performed immediately before selective coronary and bypass angiography in 33 consecutive symptomatic patients 48± 30 months after coronary surgery, for the assessment of 75 coronary bypass grafts. Forty ml of non-ionic, low-iodine content contrast medium (iohexol) were injected into the ascending aorta at 10–20 ml/sec through a 7 or 8 F femoral pigtail catheter.Electrocardiogram-triggered images were acquired on a Siemens Digitron II apparatus in multiple projections in 24 patients and in a single projection in 9 patients. The results of this technique were compared by two independent angiographers with those of selective graft angiography in the same patients. Patency was shown by DSA in 45 of 54 grafts confirmed to be open by selective angiography (sensitivity 83%). Of 21 occluded grafts, stumps were clearly visible at selective angiography in 18 and at DSA in 9 (sensitivity for graft stumns = 50%, p<0.01) Of 54 patent grafts with selective angiogranhy. the distal anastomosis could be visualized by DSA in 28 (52%), but the resolution was comparable to selective angiography in 20 grafts (37%) only. A non-significant difference in the sensitivity of DSA was observed between patent saphenous grafts to the left anterior descending coronary artery versus all other coronary arteries (95 vs 85%, respectively), while only 1 of 5 patent left internal mammary artery grafts to the left anterior descending coronary artery was visualized. In 16 of 50 grafts (32%) visualized in a second projection substantial additional diagnostic information was obtained. In conclusion, non-selective intra-arterial electrocardiogram-triggered DSA can visualize patent saphenous grafts with a high sensitivity and may be a useful screening tool for bypass grafts patency; false negatives, however, and poor visualization of distal anastomoses limit its routine clinical use.     

Thoracic aortic calcification measured by X-ray computed tomography vs age and risk factors of arteriosclerosis

The purpose of this study was to examine possible correlations among age, arteriosclerotic risk factors, and specific sites of calcification in the thoracic aorta as detected by X-ray computed tomography (CT). A total of 80 patients (mean age 59±9 years, 50 M/30 Fe) included 34 patients with ischemic heart disease, 32 with chest pain syndrome, 5 with valvular heart disease, and 9 with other diseases. The thoracic aortic calcification score, based on X-ray CT images, is the sum of the length (cm) of calcification detected in 1-cm-interval horizontal cross-sections. Differences in calcification were compared for patients with and without hypertension, diabetes, and hyperlipemia. Calcification occurred more often in the external left arch wall (52 cases), followed by the lower arch wall (50 cases). Calcification in the ascending aorta was detected in only 18 cases. Aortic calcification score ranged from 0 to 103.3 points with a mean of 8.8±14.9 points, showing a significant correlation (r=0.48,p<0.01) with patient age. However, there was no significant difference in ascending and descending aorta between sites of cross-sections. Calcification score was higher in patients with hypertension or diabetes. This difference, though significant, was very small. Moreover, patient age did have some correlation with calcification score, but the presence of ischemic heart disease and gender had no effect.A working version of this report was presented at the 36th Annual World Congress, International College of Angiology, New York, New York, July 1994     

Progression from stenosis to occlusion in the proximal native coronary artery after coronary artery bypass grafting

Coronary artery bypass grafting (CABG) is an established treatment for multivessel coronary artery disease. However, problematic situations are occasionally encountered after CABG, such as disease progression in the native coronary artery with graft occlusion, which causes difficulty in revascularization. The purpose of this study was to evaluate changes in the native coronary artery after CABG. Between 2009 and 2012 in our institution, 351 patients underwent CABG, and 768 bypass grafts were anastomosed to non-occluded coronary arteries. Of these, 489 bypass grafts had available early postoperative angiographic results (≤6 months) suitable for assessment in this study. We defined malignant graft failure after CABG to be bypass graft occlusion and de novo complete occlusion of the target native coronary artery proximal to the graft anastomosis site. In the early angiographic results, 17 grafts were occluded (17/489; 3.5 %). Two of the grafts displayed malignant graft failure (a saphenous vein graft to the right coronary artery and a saphenous vein graft to the diagonal branch) (2 of 17 occluded grafts, and 2 of 489 studied grafts). Of the patent bypass grafts, 24 involved progression to occlusion in the proximal native coronary artery (19 saphenous vein grafts, 4 left internal thoracic artery grafts, and 1 right internal thoracic artery graft). Malignant graft failure was uncommon during short-term follow-up after CABG. At the same time, disease progression in the proximal native coronary artery from stenosis to occlusion following patent bypass grafting was relatively common, especially for vein grafts.     

Use of intravascular ultrasound for in vivo assessment of changes in intimal thickness of angiographically normal saphenous vein grafts one year after aortocoronary bypass surgery.

OBJECTIVE: To use intravascular ultrasound in vivo to evaluate changes in the intimal thickness of angiographically normal saphenous vein grafts one year after implantation. DESIGN: Fifteen saphenous vein grafts in 12 patients were examined one month and 12 months after aortocoronary bypass graft surgery with intravascular ultrasound using a 30 MHz transducer. None of the grafts examined showed any angiographic abnormalities. The intimal thickness and intimal area of the graft in the proximal portion were measured on intravascular ultrasound images obtained one month and 12 months after operation. SETTING: General hospital. PATIENTS: Twelve patients who underwent aortocoronary bypass graft surgery. RESULTS: The ultrasound images showed a thin-walled graft with a thin intima one month after operation (mean (SD)) (0.31 (0.09) mm). The intimal thickness of the graft increased significantly to 0.65 (0.08) mm (P < 0.001) 12 months after operation. The intimal area of the graft was 0.90 (0.80) mm2 one month after operation. 12 months after operation the intimal area had increased significantly to 5.26 (1.38) mm2 (P < 0.001). CONCLUSION: Intravascular ultrasound in vivo showed that one year after implantation angiographically normal saphenous vein grafts had a thicker intima than one month after implantation.     

微创经左胸小切口非体外循环单支、多支冠状动脉旁路移植术33例

目的 探讨左侧肋间小切口非体外循环单支、多支冠状动脉旁路移植术的安全性和可行性。方法 回顾性分析2014年5月~2019年10月左胸前外侧小切口非体外循环下冠状动脉旁路移植术33例资料。单支病变17例,多支病变16例。左胸前外侧小切口6cm-10cm,直视下获取左乳内动脉(LIMA),完成LIMA-左前降支(LAD)吻合,升主动脉（Ao）-大隐静脉(SVG)序贯-对角支(D)或中间支（ICA）-钝缘支(OM)-后降支(PDA)或左室后支(PLV)共2~4支旁路移植血管吻合。结果 全组LIMA-LAD桥32例,Ao-SVG-LAD 1例。Ao-SVG-D 2例,Ao-SVG-OM 2例、Ao-SVG-OM-PDA 2例,Ao-SVG-ICA-PDA 3例,Ao-SVG-D-OM-PDA 4例,Ao-SVG-D-OM-PLV 3例。33例手术均顺利完成,围术期无死亡、心肌梗死、脑卒中、呼吸衰竭、肾功能衰竭、切口感染等并发症。术后呼吸机时间7h~18 h(9.14±3.82)h;ICU时间6h~20 h（12±8）h。术后住院5d~11d(8±3)d。出院时复查冠状动脉CT,33例均提示左乳内动脉桥、大隐静脉序贯桥通畅性良好。随访3个月~3年,平均8个月,无死亡、心绞痛和心肌梗死。30例复查冠状动脉, LIMA桥、SVG序贯桥通畅性良好。结论 左侧肋间小切口非体外循环下多支冠状动脉旁路移植术安全可行。     

Involvement of Lipoprotein(a) in calcification of coronary arteries and thoracic aorta as detected by X-ray computed tomography

The authors compared the severity of coronary calcification and thoracic aortic calcification as detected by x-ray computed tomography (X-ray CT) with Lipoprotein(a) [Lp(a)], and investigated whether Lp(a) is more important than total cholesterol (TC) or HDL-cholesterol (HDLC) as a risk factor for arteriosclerosis. Subjects were 64 patients (47 males, mean age 57.1±8.4 years) comprising 43 cases of ischemic heart disease, 9 cases of chest pain syndrome, 7 of valvular heart disease, and 5 of dilated cardiomyopathy. Fasted blood samples were collected early in the morning and values before medication were used. Lp(a) was measured by ELISA. Evaluation of coronary calcification by X-ray CT was performed in accordance with the procedure described in the authors' previous reports. Coronary calcification was assessed in all slices (slice thickness: 1 cm; scoring system: no coronary calcification, 0 points; coronary calcification less than 1 cm in length, 1 point; 1–2 cm, 2 points; over 2 cm, 3 points). The total score was used as coronary calcification score. For the aortic calcification score, the total number of aorta (slice thickness: 1 cm) with calcification from the superior margin of the aortic arch to the inferior cardiac margin was used. Mean scores of coronary and aortic calcification were 6.1±7.9 and 4.5±5.2 points, and Lp(a), TC, and HDLC, 23.7±23.3, 213±37, and 49.9±15.1 mg/dl, respectively. No correlation was seen between the scores of both coronary calcification and aortic calcification and any of the three lipid parameters, but for cases without coronary calcification, Lp(a) (10.6±8.5 mg/dl) was significantly lower (p<0.1) than that for cases with coronary calcification (1 vessel, 29.4±24.4; 2 vessels, 26.5±16.7; 3 vessels, 32.6±31.0 mg/dl).No significant difference was observed, however, for TC and HDLC between patients with and without coronary calcification/aortic calcification. It is suggested that Lp(a) may be a risk factor for coronary calcification. There is no correlation, however, between Lp(a) and the severity of coronary calcification. Aortic calcification is not related to the serum Lp(a) level.Presented at the 35th Annual Congress of the International College of Angiology in Copenhagen, Denmark, July 1993     

Does remodeling occur in the diseased human saphenous vein bypass grafts? An intravascular ultrasound study

Background: Coronary artery remodeling is a common phenomenon in human atherosclerotic arteries. Controversies exist concerning the presence of absence of the remodeling process in diseased human coronary saphenous vein bypass grafts. The purpose of the study was to observe the vessel and lumen dimensions in patients who had undergone saphenous vein grafting with intravascular ultrasound to find out whether the remodeling process exists in the diseased human saphenous vein bypass grafts. Methods: A total of 43 saphenous vein bypass grafts from 43 patients (39 males, 4 females, mean age 63 ± 8 years); 1–16 years (mean 9.3 ± 4.0 years) after grafting, who had not undergone previous catheter intervention, were studied using intravascular ultrasound. The vessel, lumen and plaque area were measured at the lesion segment as well as in the proximal and distal reference segments. The percent stenosis was calculated. Results: In 43 bypass grafts having severe stenosis before intervention, plaque was eccentric in 69.4% and concentric in 30.6%. No calcification was detected in 75% cases and 25% cases has mild-moderate intimal calcification. The vessel area in the lesion segment was 19.0 ± 9.7 mm², significantly larger than the proximal reference segment 12.8 ± 4.0 mm² as well as the distal reference segment 12.9 ± 3.6 mm² (p < 0.001). It was also larger than that of the average area of the proximal and distal reference segments (p < 0.001). The vessel area increased in accordance with plaque area (p < 0.001). A weak relationship existed between vessel area and percent stenosis (r = 0.37, p = 0.04). Conclusion: In contrary to previous findings, diseased human saphenous vein bypass grafts undergo focal compensatory enlargement (remodeling) in the presence of plaque formation. The underlying mechanism is probably similar to that in de novo atherosclerosis.     

Validation of coronary artery saphenous vein bypass graft diameter measurements using quantitative angiography

The accepted value for reproducibility (true change) is two standard deviations (SD) of the differences between repeat measurements. It has been well established for coronary artery measurements using several different quantitative coronary angiography (QCA) systems, but it has not been well documented for saphenous vein grafts (SVG). The purpose of this study was to assess, using the Cardiovascular Measurement System (CMS), the measurement reproducibility of 24 vein grafts from 24 patients who had symptom-directed control angiography. Three equal graft segments were studied separately. Focal narrowings expressed in percent stenosis varied from 5 to 80% (mean 20.8±15.9%). The average minimum lumen diameter (MLD) was 3.07±0.81 mm and the average interpolated reference diameter (Ref.D) was 3.87±0.58 mm. We assessed the reproducibility of measurements obtained from two separate imagings of the graft in the same view but at least 20 minutes apart, near the beginning and at the end of the angiographic procedure (simulating baseline and end-trial examinations). The SD for differences in measurements (variability) was 0.183 mm for the MLD, 0.193 mm for the Ref.D, 0.184 mm for the mean diameter (Mean D) and 3.72% for the percent diameter stenosis (PDS).A reasonable true change cut-off for SVG measurements in our laboratory is 0.4 mm for the minimum and mean lumen diameters, and 10% for the PDS, when QCA is obtained with the QCA-CMS analytical software package.     

Long-term patency of saphenous vein and left internal mammary artery grafts after coronary artery bypass surgery: results from a Department of Veterans Affairs Cooperative Study

OBJECTIVES: This study defined long-term patency of saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts. BACKGROUND: This VA Cooperative Studies Trial defined 10-year SVG patency in 1,074 patients and left IMA patency in 457 patients undergoing coronary artery bypass grafting (CABG). METHODS: Patients underwent cardiac catheterizations at 1 week and 1, 3, 6, and 10 years after CABG. RESULTS: Patency at 10 years was 61% for SVGs compared with 85% for IMA grafts (p < 0.001). If a SVG or IMA graft was patent at 1 week, that graft had a 68% and 88% chance, respectively, of being patent at 10 years. The SVG patency to the left anterior descending artery (LAD) (69%) was better (p < 0.001) than to the right coronary artery (56%), or circumflex (58%). Recipient vessel size was a significant predictor of graft patency, in vessels >2.0 mm in diameter SVG patency was 88% versus 55% in vessels 2.0 mm in diameter.     

Sequential internal mammary artery bypass for multiple coronary stenoses

Long-term studies (10 years) show a 50 per cent patency rate of saphenous vein autograft and 95 per cent patency rate of internal mammary artery coronary bypass grafts. In some situations (after saphenous vein stripping, varicose and fibrotic veins) it is not possible to use venous grafts and the internal mammary artery has to be used. However, the internal mammary artery is usually only used for revascularisation of the left anterior descending artery. Sequential internal mammary artery bypass is a technique which can be used for revascularizing the left anterior descending artery. Seven men aged 44 to 68 years (average 55 years) were operated between November 1983 and February 1985. These patients had clinically stable (4 cases) or instable (3 cases) angina. Two patients had previously undergone bilateral saphenous vein stripping and one patient a terminal anastomosis on the left anterior descending and a latero-lateral anastomosis on the diagonal artery. Three patients had an associated venous bypass graft and one patient also underwent aortic valve replacement. There were no cases of postoperative myocardial infarction. Five control angiographies were carried out during the first postoperative month. In 4 patients the internal mammary graft ant the latero-lateral and termino-lateral anastomoses were patent. In the other case, the latero-lateral anastomosis and the diagonal artery was occluded but the internal mammary graft and the termino-lateral anastomosis on the left anterior descending artery were patent. The average follow-up period is now 18 months: there have been no recurrences of chest pain or any ECG changes. These results show that internal mammary artery bypass grafting is a delicate procedure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of coronary hemodynamics in patients with internal mammary artery and saphenous vein coronary artery bypass grafts: a noninvasive approach using combined two-dimensional and Doppler echocardiography

Blood flow in bypass grafts and recipient left anterior descending coronary arteries was evaluated with combined two-dimensional and Doppler echocardiography in 15 patients with an internal mammary artery graft and in 24 patients with a saphenous vein graft. Comparative studies of coronary hemodynamics were also performed regarding these two different grafting techniques. The graft vessel was detected in 11 (79%) of 14 patients with an internal mammary artery graft and in 20 (87%) of 23 with a saphenous vein graft. The recipient left anterior descending coronary artery was detected in 10 (67%) of the former group and 17 (71%) of the latter. The blood flow patterns obtained were generally biphasic, consisting of systolic and diastolic phases with higher velocity during diastole. The maximal diastolic flow velocity in internal mammary artery grafts was much higher than that in saphenous vein grafts. In patients with an internal mammary artery graft, the flow pattern characteristics within the recipient coronary artery were quite similar to those within the arterial graft, and flow velocities within the recipient coronary artery and the arterial graft were quantitatively almost identical. This outcome may contribute to the long-term patency seen in internal mammary artery grafts. On the other hand, the flow velocity in saphenous vein grafts was fairly low throughout the cardiac cycle. Flow velocity in the recipient coronary artery in patients with a saphenous vein graft was accelerated only in early diastole. As a result, the recipient coronary artery flow pattern and velocity differed substantially from those in the saphenous vein graft.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vitro effects of L-carnitine on coronary artery bypass grafts

BACKGROUND:

The gold standard treatment for multivessel coronary revascularization is coronary artery bypass grafting. The internal mammary artery and saphenous vein grafts are the conduits most frequently used for these operations. Spasm of arterial and venous grafts is a significant problem during the operation.

OBJECTIVES:

To evaluate the acute in vitro effects of L-carnitine on internal mammary artery and saphenous vein grafts using a tissue bath.

METHODS:

Ten consecutive patients who underwent elective coronary artery bypass grafting were enrolled in the present study (nine men, one woman; mean [± SD] age 62±9.1 years). Samples from left internal mammary artery and saphenous vein grafts were collected from each patient. Submaximal smooth muscle contraction was achieved by adding 1 μM phenylephrine, and L-carnitine was then added to the solution. The concentration-response curves of the vasodilation response were obtained.

RESULTS:

In the internal mammary graft samples, the vasodilation response to L-carnitine was 64.3±11.1% at a concentration of 5 mM. In the saphenous vein graft samples, the vasodilation response to L-carnitine was 41.5±11.4% at a concentration of 5 mM. There was a statistically significant difference (P<0.001) between the response of the internal mammary artery and saphenous vein grafts in the in vitro tissue bath system.

CONCLUSIONS:

These results indicate that L-carnitine is a potential vasodilatory drug for internal mammary artery and saphenous vein grafts.     

Aortic calcification is associated with coronary artery calcification and is a potential surrogate marker for ischemic heart disease risk: A cross-sectional study

Coronary artery calcification, an established marker of atherosclerotic plaque burden associated with increased risk of coronary artery disease, is routinely evaluated using electron beam computerized tomography or multidetector computed tomography (CT). However, aortic calcification, which is also a risk factor for adverse cardiac events, is not frequently assessed, despite being easily detected via standard chest radiography. We therefore sought to clarify the association between aortic calcification and significant coronary artery calcification to determine the feasibility of performing chest radiography to evaluate the risk of future cardiovascular events.Data from 682 consecutive patients who underwent cardiac CT scanning at our institution from May to September 2012 were included in this cross-sectional analysis. Electrocardiographic-gated CT was used to qualitatively evaluate calcification in 6 aortic segments. Cardiac contrast-ehnanced CT was performed to identify significant calcification of the coronary artery. Calcification was quantified by calculating the Agatston score, and the relationship between significant coronary artery calcification and calcification at each aortic site was evaluated.Among the aortic sites, calcification was most commonly observed in the aortic arch (77.4% of patients). Significant coronary artery calcification was observed in 267 patients (39.1%). Calcification in the ascending aorta, aortic arch, descending aorta, abdominal aorta, and aortic valve were significantly associated with the presence of coronary artery calcification after adjustment for cardiovascular risk factors and statin use (odds ratios [95% confidence intervals] 4.21 [2.55, 6.93], 1.65 [1.01, 2.69], 2.14 [1.36, 3.36], 2.87 [1.83, 4.50], and 3.32 [2.02, 5.46], respectively). Mitral valve calcification was weakly but nonsignificantly associated with coronary artery calcification (odds ratio 1.84 [95% confidence interval 0.94, 3.62]). Calcification of each aortic segment assessed was significantly associated with Agatston score ≥ 100.Aortic calcification was associated with coronary artery calcification. Calcification of the aortic arch, which can be readily detected by routine chest radiography, may be associated with coronary artery calcification and its assessment should therefore be considered to identify patients at increased risk of cardiovascular events. Further studies are warranted to confirm these findings.     

Relationship between the diameter of the vein graft and postoperative ankle brachial pressure index following femoro-popliteal bypass

AIM: We studied whether the diameter of the saphenous vein graft affects the result of femoro-popliteal bypass surgery. METHODS: Thirty-eight patients with bypasses from the femoral artery to the above knee popliteal artery were studied. Bypasses without a patent anterior or posterior tibial artery were excluded. The great saphenous vein was used as a bypass graft in 20 extremities and Dacron grafts (6 mm or 8 mm diameter) were used in 18 arteries. The smallest diameter of the saphenous vein was measured preoperatively with ultrasonography. Vein grafts were divided into two groups: small vein graft (< or =3 mm) and large vein graft (> or =3.5 mm). The ankle brachial pressure index (ABI) was measured at 1 week and 3 months after operation. RESULTS: The diameter of the vein graft (2.5 to 4 mm, 3.4+/-0.5 mm) was positively correlated with postoperative ABI (R2 0.607, P<0.0001). The postoperative ABI at 1 week was significantly lower in the small vein graft group (0.72+/-0.09) than in the large vein graft group (0.95+/-0.11) and in the Dacron graft group (1.05+/-0.16). The ABI at 3 months was still significantly lower in small vein graft group (0.78+/-0.07). CONCLUSION: The diameter of the vein graft was positively correlated with postoperative ABI after femoro-popliteal above knee bypass. Postoperative ABI was lower using a vein graft with a diameter of < or =3 mm than that using a bigger vein graft or a Dacron graft.     

A comparison of morphologic and angiographic findings in long-term internal mammary artery and saphenous vein bypass grafts

Internal mammary artery grafts are currently considered the conduits of choice for myocardial revascularization. Comparisons of long-term morphologic changes in internal mammary artery grafts and saphenous vein grafts and correlation with premortem angiography have not been reported. Eighteen internal mammary artery and 15 saphenous vein grafts that had been in place for 12 to 118 months (mean 56) in 18 patients were removed either surgically or at necropsy and examined histologically. Premortem angiograms were performed within 1 month of histologic study in 15 of these patients. Fibrointimal proliferation was more frequent in internal mammary artery than in saphenous vein grafts 8 [( 44%] of 18 versus 4 [27%] of 15; p = NS). In contrast, atherosclerosis was common in saphenous vein grafts but was extremely rare in internal mammary artery grafts (10 of 15 versus 1 of 18; p = 0.01). A good correlation was noted between the degree of narrowing estimated by angiographic and histologic measurements in both internal mammary artery grafts (d = 0.90) and saphenous vein grafts (d = 0.71). Accelerated atherosclerosis did not occur in internal mammary artery grafts, but was common in saphenous vein grafts. Fibrointimal proliferation was commonly associated with graft narrowing in internal mammary artery grafts and may be an important factor in late graft closure. This study also confirms that internal mammary artery grafts have greater longevity compared with saphenous vein grafts.     

Angiographic comparison of the internal mammary artery graft and the saphenous vein graft within 2 months and 6 to 12 months after coronary artery bypass surgery

Angiographic status of the saphenous vein graft (SVG) and the internal mammary artery graft (IMAG) anastomosed to the left anterior descending artery were compared at two different postoperative periods; - within 2 months and at 6 to 12 months after the operation. In 50 SVGs and 35 IMAGs which were studied at the early postoperative period, the rate of intact, stenosed and occluded grafts were almost the same in these two kinds of grafts. However, in 35 SVGs and 25 IMAGs which were studied at the later period, the stenosis of SVG increased significantly while IMAG remained intact. The rate of intact, stenosed and occluded grafts at postoperative 6 to 12 months were 71%, 23% and 6% in SVG, and 88%, 8% and 4% in IMAG, respectively. Considering the better angiographic quality of IMAG, use of IMAG to bypass the most important coronary artery should be considered especially when the patients are younger.     

PTFE grafts to the right coronary artery following endarterectomy

In ten of 3031 patients undergoing coronary surgery, we used a PTFE graft for bypass to the right coronary artery following endarterectomy. Diffuse calcification was the reason for endarterectomy of the right coronary artery in all cases. We chose a PTFE graft only in those cases where autologous grafts were not available in a sufficient number. After a mean follow-up period of twelve months nine of the ten grafts were patent.--This study demonstrates that under selected circumstances PTFE grafts can be successfully used in coronary surgery if autologous grafts are lacking.