Minimally invasive direct coronary artery bypass grafting: midterm results and quality of life

BACKGROUND: There is increasing interest in minimally invasive direct coronary artery bypass grafting (MID-CABG); however, there is still little information about midterm results and postoperative quality of life. METHODS: From March 1995 to March 1998, 64 patients underwent MIDCABG at our hospital. Their mean age was 60+/-9.5 years; 22 (34.4%) had unstable angina. All patients were followed-up by both direct visit and questionnaire to assess the postoperative quality of life. RESULTS: There were no perioperative deaths nor conversions to sternotomy; the perioperative myocardial infarction rate was 1/64 (1.6%). Predischarge angiography showed overall and unobstructed patency rates of 96.8% (62 of 64) and 93.8% (60 of 64), respectively. At follow-up (25+/-11.4 months) actuarial survival was 100%, and survival free of myocardial infarction was 98.4%+/-1.6% at 3 years. Both the Physical Activity Score and the Psychological General Well-being Index improved significantly after the operation, with percentage improvements of 31% and 23%, respectively, at 12 months postoperatively. CONCLUSIONS: In selected patients MIDCABG can be a reliable and safe option. Patients who undergo this procedure are free of major complications and enjoy a good quality of life after surgery.     

Midterm results of coronary artery bypass graft surgery with internal thoracic artery under low free-flow conditions

Background

We use the left internal thoracic artery (LITA) even when flow is very low. In this study, we investigated midterm outcome of coronary artery bypass graft surgery with low free-flow LITA.

Methods

One hundred patients undergoing coronary artery bypass graft surgery using LITA with a free flow of less than 20 mL/min were reviewed. The mean follow-up duration was 47.4 months, ranging from 1 to 65 months. Graft angiography was performed postoperatively. The diameter of the LITA was assessed angiographically. Cumulative graft patency, cardiac-related event-free rate, and actuarial survival rate were calculated by the Kaplan-Meier method.

Results

An early postoperative Doppler study showed that the diastolic-to-systolic ratio in the LITA was 1.76 ± 0.33. A 1-month postoperative angiography revealed LITA string sign in 2 patients. One had a percutaneous coronary intervention, whereas string sign was not detected in the second patient, and LITA patency showed a marked improvement in 1-year postoperative angiogram. One month postoperatively the LITA diameter was 1.6 ± 0.4 mm, and significantly enlarged in the second angiogram (1.9 ± 0.4 mm, p = 0.0003). There was a significant correlation between the diameter of the LITA and the left anterior descending coronary artery (r = 0.889, p = 0.0001). The cumulative graft patency rate at 1 and 4 years was 99.0% and 94.3%, respectively. The cardiac-related event-free rate at 1 and 5 years was 97.0% and 93.3%, respectively. The actuarial survival rate at 5 years was 97.1%.

Conclusions

Even with a very low LITA free flow, graft function improves with LITA growth, if there was no mechanical damage that impedes recovery.     

Bilateral internal thoracic artery grafting: midterm results of composite versus in situ crossover graft

BACKGROUND: Two common techniques of bilateral internal thoracic artery grafting are the composite T graft and in situ crossover graft. The superiority of one method over the other has not yet been established. METHODS: From April 1996 to July 1999, bilateral skeletonized internal thoracic arteries were used as T grafts (composite group, n = 649) and in situ grafts (cross group, n = 351) in 1,000 consecutive patients. In the cross group, in situ right internal thoracic artery was routed anterior to the aorta across the midline for grafting to the left anterior descending artery, and the left internal thoracic artery was used for the circumflex branches. RESULTS: The two groups had comparable preoperative risk profiles. Bypass time and aortic cross-clamping time were longer in the composite group (80 +/- 38 and 67 +/- 29 minutes versus 66 +/- 43 and 55 +/- 34 minutes, respectively). Number of anastomoses per patient was similar (3.1 versus 3.2). However, more sequential anastomoses were performed in the composite group (62% versus 53%), and the gastroepiploic artery was used more often in the cross group (30% versus 19%). Thirty-day mortality was 3.9% in the composite and 2.3% in the cross group (not significant). Occurrence of postoperative complications (sternal infection, myocardial infarction, cerebrovascular accident, and bleeding) was similar. Late follow-up (2 to 56 months) showed increased return of angina (6% versus 3.1%; p = 0.046) and decreased 4-year survival (Kaplan-Meier; 86% +/- 2.7% versus 92.4% +/- 1.5%; p = 0.07) in composite patients. CONCLUSIONS: Early results of bilateral internal thoracic artery grafting with composite T graft are comparable with those of in situ grafts. However, increased angina return and decreased midterm survival led us to recommend in situ grafting whenever technically possible.     

Failure of internal thoracic artery grafts: conclusions from coronary angiography mid-term follow-up

BACKGROUND: The objective of this study was to identify causes of the failures of internal thoracic artery bypass grafts according to operative technique, the internal thoracic artery used, and the coronary artery grafted. METHODS: This retrospective study concerns 302 follow-up angiographies performed in patients treated with 512 internal thoracic artery bypass grafts: 115 single grafts, 78 sequential grafts, and 109 grafts with two internal thoracic arteries (61 Y grafts). Postoperative angiography was performed after a mean period of 17.3 +/- 4.1 months. RESULTS: Failures consisted of 11 (2%) occluded grafts and 19 (4%) nonfunctioning grafts (threadlike internal thoracic artery). There was no difference in patency among the various types of left anterior descending artery bypass grafts anastomosed with the left internal thoracic artery. The failure rate was higher with the right internal thoracic artery (13%) than with the left internal thoracic artery (4%; p < 0.05). The failure rate of the left anterior descending artery bypass grafts (3%) was lower than that for the branches of circumflex artery bypass grafts (13%; p < 0.05). The 19 cases of nonfunctioning grafts did not include significant anastomotic stenosis: 14 were related to competitive blood flow, 4 to a poor recipient coronary arterial bed, and 1 to significant distal coronary stenosis. CONCLUSIONS: At least two thirds of failures of bypass grafts could have been avoided by more objective analysis of the coronary stenosis on preoperative coronary angiography and better mastery of the surgical technique.     

Flow dynamics in internal thoracic artery grafts 10 years after coronary artery bypass grafting

BACKGROUND: Flow dynamics in internal thoracic artery grafts 10 years after surgery are not known. METHODS: Doppler examination was performed in native internal thoracic arteries as a control (n = 8) and in internal thoracic artery grafts to the left anterior descending coronary artery 6 months postoperatively (group A, n = 25), at 5 years (group B, n = 14), and at 10 years (group C, n = 11). RESULTS: Each graft group showed a diastolic to systolic peak velocity ratio of less than 1.0 at the proximal end, and more than 1.0 at the distal end, but the control group showed a ratio of less than 1.0 throughout the length of the artery. The diastolic peak velocity of the graft groups was significantly faster than that of the control group at the distal end (versus group A, p < 0.01; versus group B, p < 0.005; and versus group C, p < 0.05). The systolic peak velocity of the graft groups was significantly lower than that of the control at the proximal end (versus group A, p < 0.0001; versus group B, p < 0.005; and versus group C, p < 0.0005). There were no significant differences of flow velocities among the graft groups and graft diameter among the four groups. CONCLUSIONS: Although the internal thoracic artery is systolic predominant, when native artery is used as graft, it changes its hemodynamics to diastolic predominance, especially at the distal end. Even after 10 years, graft flow dynamics are unchanged. This hemodynamic character may be one of the factors related to the superior long-term patency.     

Minimally invasive direct coronary artery bypass grafting: intermediate-term results

BACKGROUND: Intermediate- and long-term clinical outcome and graft patency in minimally invasive direct coronary artery bypass grafting (MIDCABG) procedures remain a concern. METHODS: Over a 13-month period, 66 MIDCABG procedures were performed utilizing robotic-assisted internal mammary artery (IMA) harvesting and direct CABG through a 5-cm thoracotomy without cardiopulmonary bypass. Clinical follow-up was obtained on all patients. Graft patency was assessed in 61 of 66 consecutive patients 6 months (range 2 to 15 months) postoperatively. Group I consisted of 45 patients who underwent IMA angiography and group II consisted of 16 patients who underwent both a nuclear stress test and transthoracic Doppler examination. All group II patients had abnormal preoperative nuclear stress tests for comparison. RESULTS: To date, all 66 patients are alive. Graft patency rates in the two groups were 97.8% (45 of 46 grafts in 45 patients) in group I and 100% (15 of 15 grafts), with one indeterminate study, in group II. The overall patency rate for the entire study group was 98.3% (60 of 61 grafts). Sixty-two of 66 (93.9%) patients were able to return to their normal level of activity within 3 weeks. CONCLUSIONS: This study demonstrates that the MIDCABG with thoracoscopic IMA harvesting can achieve effective intermediate-term revascularization and an acceptable clinical outcome.     

Limitations of right internal thoracic artery to left anterior descending artery bypass: a comparative quantitative study of postoperative angiography of the bilateral internal thoracic artery bypass grafts

BACKGROUND: It remains controversial whether right internal thoracic artery (RITA) to left anterior descending artery (LAD) bypass has qualitative limitations which cannot be evaluated based on the patency rate alone. METHODS: The 111 subjects underwent graft angiography after bypass grafting of the left or right internal thoracic artery (ITA) to the LAD. The vascular caliber was measured at the origin of the ITA, at an ITA site adjacent to the anastomotic site, and at an LAD site immediately below the anastomotic site, regarding the outer diameter of the catheter as a reference. RESULTS: The caliber of the ITA immediately above the anastomotic site of the LAD was significantly lower in the RITA group. In the left internal thoracic artery (LITA) group, no patient showed a caliber of less than 1.25 mm, but five patients (7.8%) did in the RITA group. The preoperative cardio-thoracic ratio was significantly higher than that in patients in whom the caliber of the ITA immediately above the anastomotic site was 1.25 mm or more, and the height was significantly lower. CONCLUSIONS: In many patients, the RITA is appropriate as a graft material to the LAD. However, in patients with a high cardio-thoracic ratio and those with a low height, the RITA may not reach the LAD in a favorable state, and the LITA should be anastomosed to the LAD in some patients.     

Long-term results of coronary artery bypass grafting in patients with renal insufficiency

BACKGROUND: There are few published studies on coronary artery bypass grafting in patients with renal insufficiency who are not on maintenance dialysis. No details of long-term results have been published. METHODS: This retrospective study focuses on 117 consecutive coronary artery bypass grafting patients with renal insufficiency, but who did not require dialysis (group B: preoperative serum creatinine level > or = 1.5 mg/dL). For comparison purposes, patients on maintenance dialysis (group C: 84 patients) and patients with normal renal function (group A: 794 patients; preoperative serum creatinine level < 1.0 mg/dL) were selected. RESULTS: Hospital mortality was 11% (13 of 117) in group B, 5.9% (5 of 84) in group C, and 1.6% (13 of 794) in group A, and between groups A and B, p < 0.0001, and between groups B and C, p = 0.24. Actuarial survival rates at 10 years, including all deaths, were 87%, 32%, and 29% in groups A, B and C, respectively, and between groups A and B, p < 0.009 and between groups B and C, p = 0.63. In 23 patients in group B, the bilateral internal thoracic artery was used. No cardiac deaths were observed in these patients during the mean follow-up time of 42 months (range, 1 to 128 months). Cox model analysis revealed nonuse of arterial grafting (p = 0.03; Hazards ratio 1.7) to be a statistically significant factor, and renal insufficiency (p < 0.0001; Hazards ratio 3.3) and maintenance dialysis (p < 0.0001; Hazards ratio 5.6) to be major independent risk factors for actuarial survival. CONCLUSIONS: Renal insufficiency was shown to be an independent risk factor for poor prognosis after coronary artery bypass grafting. However, aggressive use of arterial grafts, especially the internal thoracic artery, is recommended to improve late outcomes.