Tetsuji Kawata

Does skeletonization compromise the integrity of internal thoracic artery grafts

BACKGROUNDnThere are few reports that demonstrate the chronologic changes in the functional integrity of the internal thoracic artery (ITA) wall after skeletonization. We investigated the impact of skeletonization on ITA wall integrity by immunohistochemical analyses in acute and chronic phases.nnnMETHODSnNine mongrel dogs underwent bilateral ITA dissection with one skeletonized vessel and the other pedicled. The following studies were performed 1 week (acute phase, n = 3) and 12 weeks (chronic phase, n = 6) after ITA harvesting. All specimens of the ITAs were stained by antibodies against von Willebrand Factor (VWF), endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and proliferating cell nuclear antigen (PCNA). After observation with confocal laser scanning microscopy, quantitative analyses of the staining signal for VWF and eNOS expressed on endothelial cells were performed.nnnRESULTSnThere were significantly more microvessels positive for VWF in the adventitia of skeletonized ITAs than in the adventitia of pedicled ITAs but the expression of PCNA in both groups was minimal, as in normal vessels. iNOS was not detected in any specimen. The intensity of VWF and eNOS expressed by endothelial cells had no significant differences between groups at either phase.nnnCONCLUSIONSnThe functional integrity of skeletonized ITA was similar to that of pedicled ITA in both acute and chronic phases. Although skeletonization induced neovascularization in the adventitia it did not induce proliferation of smooth muscle cells in the media, which is supposed to be a feature of vascular remodeling.

Long-term Benefits of Internal Thoracic Artery-Coronary Artery Bypass in Japanese Patients

OBJECTIVESnThis study sought to determine the effects of grafting the internal thoracic artery (ITA) to the left anterior descending coronary artery (LAD) on long-term (10-year) survival, the cardiac death-free rate, and on the cardiac event-free rate in Japanese patients.nnnBACKGROUNDnThe use of ITA grafts has been reported to enhance postoperative survival and to decrease the occurrence of cardiac events in the Western literature. However, the survival benefits in Japanese patients, who may have different prognoses with coronary artery disease and a different fate of a saphenous vein graft, have not yet been determined.nnnSUBJECTS AND METHODSnA total of 954 consecutive patients who underwent coronary artery bypass graft operations (CABG) during the last 12 years at the Nara Medical University were followed and evaluated. Of these, 713 patients underwent ITA-CABG to at least the LAD (ITA group), and 241 patients received a saphenous vein graft (SVG) to the LAD (SVG group). At the time of operation, no significant difference was found between these two groups in age, sex ratio left ventricular ejection fraction, left ventricular end-diastolic pressure, cardiac index, incidence of unstable angina, or in the necessity for an emergency operation. However, those patients who received ITA-CABG had significantly higher incidences of diabetes mellitus, hyperlipidemia, and left main coronary artery disease.nnnRESULTSnThe 10-year cumulative graft patency rate for the LAD was 23% higher in the ITA group (90.3%) compared to the SVG group (67.0%), (p < .0001). Despite increased preoperative risk factors, patients in the ITA group showed significant improvements in their 5- and 10-year cumulative survival rates as well as in their cardiac death-free and event-free rates. Furthermore, this study demonstrated that ITA grafts improved the prognoses of patients with diabetes mellitus or left ventricular dysfunction and lowered both the long-term postoperative cardiac-death rate and the cardiac-event rate.nnnCONCLUSIONSnThe use of ITA grafts was effective in improving both the postoperative survival and cardiac event-free rates, and should be recommended in patients with diabetes mellitus or left ventricular dysfunction. ITA grafting to the LAD should be a routine operation in almost all categories of such patients.

Aortic valve replacement in a patient with a patent internal thoracic artery graft

Myocardial protection in patients requiring a second open-heart surgical procedure after coronary artery bypass grafting, especially when there is a patent left internal thoracic artery graft to the left anterior descending coronary artery, remains controversial. We present the case of a patient in whom aortic valve replacement was undertaken 18 months after coronary artery revascularization. Unusual features included beating-heart aortic valve replacement with continuous retrograde coronary sinus perfusion and avoidance of dissection of the patent grafts, including the left internal thoracic artery and a saphenous vein graft.

Comparative Rest and Exercise Hemodynamics of Allograft and Prosthetic Valves in the Aortic Position

BACKGROUNDnAllograft aortic valve replacement has gained widespread acceptance. However, there is little information about in vivo allograft valve function at rest and during exercise.nnnMETHODSnCardiac catheterization was performed to measure hemodynamic variables at rest and during supine bicycle exercise in 44 patients who had had aortic valve replacement using allograft valves or Bicer or St. Jude Medical prosthetic valves 19 to 27 mm in diameter. Sixteen patients received an allograft valve; 17, a Bicer valve; and 11, a St. Jude Medical valve. There were no significant differences between the three groups in age, body surface area, left ventricular end-systolic and end-diastolic volume indices, exercise cardiac index, exercise heart rate, or work load achieved. Left ventricular and ascending aortic pressures were measured simultaneously according to the transseptal method.nnnRESULTSnThe mean pressure gradient was generally higher for the Bicer and St. Jude Medical valves than for the allograft valves, both at rest and during exercise. Significant differences were obtained in patients with small-sized valves (21 and 23 mm); pressure gradients were higher in the prosthetic valve groups. In patients with large-sized prosthetic valves (25 mm), there were no significant differences between the three groups at rest and during exercise. However, there was no pressure gradient at all for allograft valves.nnnCONCLUSIONSnExercise cardiac catheterization confirms that the allograft aortic valve is an ideal substitute from the hemodynamic aspect, particularly in patients with a small aortic root and in those who perform strenuous exercise.

Minimally Invasive Direct Coronary Artery Bypass Combined With Abdominal Aortic Aneurysm Repair

BACKGROUNDnFor simultaneously combined coronary artery bypass surgery with infrarenal abdominal aortic aneurysm (AAA) repair, a relatively high operative mortality and morbidity have been reported.nnnMETHODSnFrom February 1998 to December 1998, simultaneous minimally invasive direct coronary artery bypass combined with the AAA repair was performed for 4 patients (3 males, 1 female; mean age, 74+/-7 years). Three were high-risk patients: 2 were over 75 years of age, 2 had respiratory insufficiency, and 1 had severe renal impairment.nnnRESULTSnThere were no mortalities. The endotracheal tube was removed within approximately 12 hours, and the postoperative courses were uneventful. During 4+/-4 months of follow-up, there was neither angina recurrence nor other morbidity.nnnCONCLUSIONSnMinimally invasive direct coronary artery bypass combined with AAA repair was safe even for high-risk patients.

Benefits accruing to grafting of the right internal thoracic artery to the left anterior descending artery in coronary artery bypass grafting.

OBJECTIVESnWe have investigated the effects and outcome from grafting the right internal thoracic artery to the left anterior descending artery in coronary artery bypass grafting.nnnMETHODSnWe analyzed the findings in 185 patients who underwent coronary artery bypass grafting involving right internal thoracic artery-left anterior descending artery bypass. The survival rate, cardiac events related to the right internal thoracic artery-left anterior descending artery graft, and graft patency were investigated. In cardiac catheterization, the production of nitric oxide from the endothelium of the internal thoracic artery was measured as the plasma nitrite and nitrate levels by the Griess reaction. The reactions to acetylcholine infusion (5 micrograms) in the right internal thoracic artery (n = 4) were compared to those in the left internal thoracic artery (n = 9) grafts.nnnRESULTSnThe hospital mortality rate was 0.5%. The actuarial survival rate at 11 years after operation was 98.81%. The rate of freedom from cardiac events at 11 years after operation was 92.08%. The rate of patency of the right internal thoracic artery-left anterior descending artery was 97.0% in 133 patients. Nitric oxide production was calculated as (total nitrite plus nitrate production in response to stimulation by acetylcholine-total nitrite plus nitrate level before acetylcholine load)/(total nitrite plus nitrate level before acetylcholine load). There was no significant difference in changes in plasma concentration in response to acetylcholine stimulation between the right internal thoracic artery-left anterior descending artery and left internal thoracic artery-left anterior descending artery groups (20 +/- 29% versus 5 +/- 10%).nnnCONCLUSIONSnThe right internal thoracic artery-left anterior descending artery grafts exhibited good patency and release of nitric oxide in response to acetylcholine loading, similar to left internal thoracic artery-left anterior descending artery grafts.

Concomitant transabdominal MIDCAB and abdominal aortic aneurysm repair

We present 2 patients who underwent transabdominal minimally invasive direct coronary artery bypass with the right gastroepiploic artery combined with abdominal aortic aneurysm repair. The surgical procedures, both performed through a median laparotomy, proved safe and of limited invasiveness. The one-stage surgical intervention prevented catastrophic complications, such as acute myocardial infarction or rupture of abdominal aortic aneurysm. We believe that concomitant transabdominal minimally invasive direct coronary artery bypass and abdominal aortic aneurysm repair should be considered as a single combined surgical strategy in selected patients.

Reoperative coronary artery bypass grafting using a minimally invasive direct coronary artery bypass procedure.

OBJECTIVEnReoperative coronary artery bypass grafting with cardiopulmonary bypass tends to cause a higher mortality and morbidity than the primary operation. The purpose of this study was to discuss the effectiveness and safety of a minimally invasive coronary artery bypass procedure for patients who had previously undergone coronary artery bypass surgery.nnnMETHODSnWe performed redo single coronary artery bypass grafting to the left anterior descending coronary artery in 9 patients and to the right coronary artery in 3 patients using minimally invasive cardiac surgery. The graft to the left anterior descending coronary artery was taken from the left internal thoracic artery in 5 patients, the right gastroepiploic artery in 3 patients, and from the saphenous vein in the other 1 patient. The graft to the right coronary artery was from the right gastroepiploic artery in all 3 patients.nnnRESULTSnAll grafts were patent. There was no major postoperative complication and no surgical or hospital death except one late death.nnnCONCLUSIONSnIn selected patients, we could safely and completely perform coronary artery bypass re-grafting to the left descending coronary artery or right coronary artery using a minimally invasive operation.

Modification of Repeat Coronary Bypass Grafting for the Left Anterior Descending Artery with a Minimally lnvasive Direct Coronary Artery Bypass Technique

Abstract Background: The usefulness of minimally invasive direct coronary artery bypass (MIDCAB) for reducing mortality and morbidity associated with repeat coronary artery bypass grafting (re‐CABG) has been reported. In re‐CABG, graft selection and operative procedures are determined according to the previous mode of CABG. Methods: We performed three types of operations using MIDCAB techniques for rerevascularization of the left anterior descending artery (LAD) using (1) the in situ left internal thoracic artery, (2) the in situ right gastroepiploic artery, and (3) a reversed saphenous vein graft anastomosed to the left axillary artery. Results: In all cases, the postoperative course was uneventful. None of the patients had any symptom of ischemia postoperatively. Conclusions: In re‐CABG for rerevascularization of LAD, a modified MIDCAB technique using one of the above three procedures should be considered.