Shigeyuki Takeuchi

New technique for the arterial switch operation in difficult situations

The technique described here, a modification of the Aubert operation, avoids coronary reimplantation and also eliminates the need to use artificial material to transfer coronary circulation.

Routine extended graft replacement for an acute type a aortic dissection and the patency of the residual false channel

BACKGROUND Recent surgical progress has had an impact on the mortality of acute type A aortic dissection. Routine aortic arch replacement, irrespective of the location of the intimal tears, may improve not only the outcome of the residual dissection but the operative mortality, because complete resection of intimal tears, including those invisible through the aortotomy in the ascending aorta is achieved. METHODS During the past 7 years, total aortic arch replacement was performed in 50 consecutive patients with acute type A aortic dissection. Cerebral protection was achieved by deep hypothermia associated with pharmacologic cerebroplegia. Computed tomography and aortic angiography were performed to examine 48 patients for the possible presence of residual false channels before discharge. RESULTS The duration of circulatory arrest ranged from 30 to 84 minutes. The hospital mortality was 10%, and a cerebral complication was observed in 1 patient. No evidence of a persisting false channel was detected in 27 patients (54%) who were totally thrombosed. During the follow-up period (range: 2 months to 7 years), 2 patients died of hepatoma or pneumonia, respectively, and 2 patients underwent reoperation for recurrence of a dissection at the sinus of Valsalva. The Kaplan-Meier method estimated a 7-year survival of 82%, and a 7-year freedom from reoperation of 93%. CONCLUSIONS These results suggest that our aggressive use of routine aortic arch grafting can be accomplished with an acceptable risk and that our strategy not only improved the late results but the mortality associated with repairs for acute type A aortic dissection.

Risks and benefits of bilateral internal thoracic artery grafting in diabetic patients.

BACKGROUND There is a tendency to avoid the bilateral internal thoracic artery (ITA) grafting in diabetics. However, we no longer consider diabetes a reason for excluding the bilateral use of ITAs. We compare the early and long-term results in diabetic cases treated by coronary artery bypass grafting (CABG) using unilateral and bilateral ITA grafts. METHODS A total of 303 consecutive diabetic cases of CABG using ITA grafts between April 1991 and January 2003 were reviewed. Of these, 149 (49%) were being treated with insulin. The cases were divided into two groups: 179 cases in which bilateral ITA grafts had been used and 124 in which a unilateral ITA graft had been used. RESULTS The mortality for the bilateral ITA group and unilateral ITA group were 1.7% and 1.6%, respectively. The fact that patients were receiving insulin had no effect on the mortality of CABG. A review of morbidity revealed that no differences were found between the two groups. The survival curves, cardiac-death-free curves, and cardiac-event-free curves showed that there was no difference between the use of one or two ITA grafts in diabetics, while bilateral use of ITA grafts was significantly better than unilateral use in a comparable group of nondiabetics operated during the same time period. CONCLUSIONS There was no significant difference in operative mortality related to single or double ITA grafting in diabetics. There was also no difference between the use of one or two ITA grafts in diabetics in regard to long-term follow-up.

Hemodynamic evaluation of 19-mm Carpentier-Edwards pericardial bioprosthesis in aortic position

BACKGROUND The aortic Carpentier-Edwards pericardial bioprosthesis offers good long-term clinical outcomes with a low rate of structural deterioration. However, little in vivo hemodynamic data is available for this bioprosthesis. METHODS To determine the hemodynamic performance of the 19-mm Carpentier-Edwards pericardial valve, both cardiac catheterization and dobutamine stress echocardiography were electively performed in 10 patients. The mean age at the study was 71.6 +/- 4.4 years and the mean body surface area was 1.39 +/- 0.11 m2. The peak-to-peak gradient, instantaneous peak gradient, mean gradient, and valve orifice area were measured by standard cardiac catheterization. The Doppler-derived gradients and valve orifice area were also measured both at rest and during dobutamine infusion. RESULTS The average peak-to-peak gradient, instantaneous peak gradient, mean gradient, and valve orifice area measured by catheterization were 13.0 +/- 5.4 mmHg, 28.5 +/- 7.7 mmHg, 12.0 +/- 4.9 mmHg, and 1.55 +/- 0.45 cm2, respectively. The peak and mean Doppler gradients, and valve orifice area by resting echocardiography were 27.7 +/- 9.5 mmHg, 12.3 +/- 4.8 mmHg, and 1.39 +/- 0.26 cm2, respectively. At a dosage of 10 microg/kg/min of dobutamine, the mean Doppler gradient rose mildly to 22.2 +/- 4.8 mmHg, while the cardiac output increased from 4.49 +/- 0.44 to 6.64 +/- 0.87 L/min. The valve orifice area during the 10 microg/kg/min dobutamine infusion (1.55 +/- 0.25 cm2) was significantly larger than its value at rest (p < 0.05). CONCLUSIONS With acceptable hemodynamic performance, use of the aortic 19-mm Carpentier-Edwards pericardial valve is a reliable option for elderly patients with a small annulus.

Feasibility and suitability of the routine use of bilateral internal thoracic arteries

BACKGROUND It has been demonstrated that bilateral use of internal thoracic arteries (ITAs) confers better long-term results in patients than does unilateral use. However, routine use of bilateral ITAs has usually been avoided. METHODS Since 1997, we have used bilateral ITAs extensively for patients who required multivessel bypasses. Recently, 243 consecutive patients, including 127 diabetic patients, were reviewed. RESULTS Every patient received at least one ITA graft, and 200 patients (82%) received bilateral ITAs. The majority (93%) of ITA grafts were used as in situ grafts. The hospital mortality rate was 0.41%, and deep sternal infections were observed in 5 patients (2.0%). There was no difference in the incidence of chest wound infection between the group treated with bilateral ITA grafting and that treated by unilateral ITA grafting. CONCLUSIONS These observations suggest that ITAs can be used bilaterally for treatment in the majority of patients who require multivessel bypass, with low mortality and morbidity.

Cardioscopic guidance of linear lesion creation for radiofrequency ablation

BACKGROUND The broad use of catheter ablation of atrial fibrillation is limited by the difficulty inherent in creating transmural linear lesions under fluoroscopy. Therefore, we evaluated cardioscopy as a more accurate method of guiding the catheter for the placement of linear lesions. METHODS Nineteen swine underwent endocardial ablation to create linear conduction block lesions in the right atrium under cardioscopy (group I, n = 13) or fluoroscopy (group II, n = 6). In both groups, the linear lesion was created between the superior and inferior vena cava, perpendicular to hexapolar electrodes placed on the epicardial surface. Each swine received two pairs of epicardial hexapolar electrodes: one pair to measure the conduction delay time across the ablated line and another pair for pacing. The time spent to complete the ablation, number of trials and effective ablations, ratio of effective ablations to trials, length of the lesion, conduction delay under pacing, and postmortem pathology were compared between the two groups. RESULTS Statistically significant differences were found for the time required for ablation, ratio of effective ablation to total number of trials, and conduction delay. Histologic analysis revealed more homogenous, continuous lesions in group I. CONCLUSIONS Cardioscopy facilitated the placement of a conduction block line more efficiently than ablation performed under fluoroscopy. Landmarks of tissue relevant to ablation are readily visualized by cardioscopy. Moreover, cardioscopy can be useful for the development of a guiding catheter for the ablation of atrial fibrillation.

Surgical management of the straddling mitral valve in the biventricular heart.

BACKGROUND The straddling mitral valve in the biventricular heart is a rare condition that may complicate biventricular repair. METHODS Treatment and outcomes in 5 consecutive patients who underwent primary repair between 1992 and 1997 were reviewed. Their ages at repair ranged from 2 months to 8 years. Three patients had a double-outlet right ventricle with a subaortic (n = 2) or subpulmonary (n = 1) ventricular septal defect. Two patients had transposition of the great arteries (S,D,D), a ventricular septal defect, and left ventricular outflow tract obstruction. The attachments of the papillary muscles of the straddling mitral valves were located on the right ventricular aspect of the ventricular septum. Four patients underwent baffle partitioning of the ventricular cavity. The baffle suture line was used to secure the chordae tendineae crossing the ventricular septal defect, or was intentionally omitted at the papillary muscle. The right ventricular outflow tract was reconstructed with patch augmentation, an extracardiac conduit, or an arterial switch operation. One patient with transposition who had a giant papillary muscle to the straddling mitral valve associated with abnormal insertion of the tricuspid valve on the conal septum underwent univentricular repair. RESULTS There were no early or late postoperative deaths. There was no mitral valve dysfunction, left ventricular outflow tract obstruction, or heart block in the 4 patients who underwent biventricular repair. CONCLUSIONS Although there are several exceptional situations in which ventricular partitioning may result in early and late complications, a straddling mitral valve does not preclude biventricular repair.

Mitral valve replacement in patients younger than 6 years of age

UNLABELLED We present our experience in mitral valve replacement (including left-sided tricuspid valve in corrected transposition) in patients younger than 6 years of age. The long term results were examined with special focus on re-replacement of the valve. Between 1974 and 1995, we performed mitral valve replacement in 14 patients younger than 6 years of age, with no operative mortality. There were 3 late deaths, caused by endocarditis, valve thrombosis, and congestive heart failure, respectively. The five-year-survival rate after primary replacement was 85%, and the ten-year-survival rate was 75%, using Kaplan-Meier analysis. Ten patients (11 occasions) required repeated mitral valve replacements at 2 months to 17 years after the original replacement. The indication for the second or third mitral valve replacement was paravalvular leakage (2 patients), valve thrombosis (1 patient), degeneration in the porcine prosthesis (3 patients), and patient outgrowth of the original small prosthesis (5 patients). Again there was no operative mortality. One patient who suffered from multiple occasions of valve thrombosis died at two years after the second replacement. All patients who had outgrown the prosthetic valve received larger prosthesis at the second replacement than at the primary replacement. The actuarial percentage of freedom from valve-related events at 3 years, 5 years, and at 10 years, was 50%, 37%, and 8%, respectively. CONCLUSIONS Mitral valve replacement in patients younger than 6 years of age can be performed relatively safely, but meticulous follow-up and appropriate decision making for re-replacement is mandatory for the long-term survival of these patients.

Complications following reparative surgery for aortic coarctation or interrupted aortic arch

Repair of aortic coarctation or interrupted aortic arch continues to be associated with major long-term morbidity. Thus, we conducted a review of 87 consecutive patients who underwent aortic arch repairs, focusing particular attention on the complications that developed. A two-stage strategy was employed if cardiac lesions were associated. The median age at surgery was 1.5 months with a range of 12h to 56 years. The aortic arch was repaired using end-to-end anastomosis, subclavian flap aortoplasty, subclavian arterial turning-down aortoplasty, patch aortoplasty, tube graft interposition, or other methods. There were 10 patients who died soon after repair, and all of whom had complex cardiac anomalies. Of the remaining 77 patients, 8 developed recurrent stenosis. These 8 patients were all similar in age, being under 3 months old, and weighing 4 kg or less. A multivariable analysis of the infants identified interrupted aortic arch as an independent risk factor for the development of this complication with an odds ratio of 6.45. Complications following prosthesis-free techniques were similar in prevalence and timing. All reinterventions were mortality-free, but catheter dilation and patch aortoplasty were not always successful. Three extraanatomic bypasses were successfully performed, and one adult who had undergone a previous graft and pseudoaneurysm operation was successfully treated with an extraanatomic bypass. These findings led us to conclude that the initial repair should be performed without a prosthesis, and that reintervention for stenosis should combine catheter dilation and extraanatomic bypass.

Correction of total anomalous pulmonary venous connection of the cardiac type

Surgical treatment of the cardiac type of total anomalous pulmonary venous connection requires special techniques. The treatment and outcome in 17 consecutive patients who had undergone primary repairs of the cardiac type between 1965 and 1996 were reviewed. The median age was 3 months and median weight 4.2 kg. The connection was the coronary sinus in ten patients, and the right atrium in six. Interatrial communication was routinely augmented. The right atrial cavity was partitioned using a patch to direct the anomalous pulmonary veins into the left atrium through the atrial septal defect in the first 13 patients. In the last four patients, the free wall flap of the right atrium was developed as a neoseptum. There were three early postoperative deaths during the early period of conventional repair. Two patients developed residual or recurrent diffuse obstruction in the individual lobar veins; reoperation to relieve the obstruction was attempted but unsuccessful. One sudden death occurred in a patient with occasional heart block. Ten survivors have been asymptomatic during follow-up, but two incomplete heart blocks and one atrial flutter were noted among patients who underwent conventional repair. The right atrial wall flap technique was not associated with any mortality or morbidity, such as arrhythmia and recurrent pulmonary vein stenosis during 12 to 63 months of postoperative obstruction. In conclusions, a flap technique using the right atrial wall appears to be a promising method to decrease the incidence of supraventricular arrhythmias and pulmonary vein drainage obstruction following repair of the cardiac type.