Virtual Reality Computed Tomography Evaluation - Anatomy and Clinical Implications for Valve-Sparing Aortic Root Replacement

BACKGROUND

Three-dimensional aortic root evaluation using virtual reality (VR) techniques for valve-sparing aortic root replacement (VSARR) preparation has not yet been implemented, so we demonstrated VR computed tomography (VR-CT) and assessed its utility for VSARR.Methods and Results: We enrolled 72 patients who underwent multidetector CT before elective VSARR for annuloaortic ectasia with tricuspid aortic valve. The geometries of their aortic roots were measured with a VR-CT workstation. The mean values of geometric height (GH), free margin length (FML), and commissural height (CH) were 17.2±2.4 mm, 36.0±5.2 mm, and 24.0±4.3 mm, respectively. The right coronary/noncoronary CH was significantly greater than the left coronary/right coronary and left coronary/noncoronary CH. The left coronary cusp had the shortest FML, intercommissural distances (ICD), and smallest central angle. Although the right coronary cusp had the largest values for FML, ICD, and central angle, the right coronary cusp had the lowest GH and EH. The VR-CT measurements strongly correlated with intraoperative alternatives, especially with mean GH (R2=0.75) and left coronary/noncoronary CH (R2=0.79). Furthermore, mean GH was observed to be significantly different among the selected graft size groups; therefore, the preoperative mean GH could play a significant role in graft sizing.

CONCLUSIONS

VR-CT evaluation allows a thorough understanding of aortic root anatomy, which could facilitate VSAAR.

[Thoracic Endovascular Aortic Repair for Stanford Type B Acute Aortic Dissection with Right Leg Malperfusion:Report of a Case]

We report a case of complicated Stanford type B acute aortic dissection with malperfusion to the right leg. The patient received conservative treatment in a previous hospital. However, he complained of pain in the right leg, which had been gradually turning pale. The patient was diagnosed with complicated Stanford type B acute aortic dissection with right leg malperfusion and was transferred to our hospital for treatment. Thoracic endovascular aortic repair (TEVAR) to close the entry to the distal aortic arch was performed, and we embolized the left subclavian artery to prevent type Ⅱ endoleak and to extend the stent-graft landing zone. We implanted a bare stent into the right external iliac artery to enlarge its true lumen. The patient was discharged from our hospital 22 days postoperatively. After the operation, computed tomography( CT) scan showed an aortic false lumen remodeling.

[Our Experience and Technical Improvement in Robot-assisted Cardiac Surgery]

Since 2014, we have used the da Vinci surgical system to perform internal thoracic artery harvest in minimally invasive direct coronary artery bypass (MIDCAB), and since 2016, we have also performed robot-assisted cardiac surgery( RACS) for mitral and tricuspid valve surgery, left atrial thrombosis, and myxoma, all of which we have had performed as minimally invasive cardiac surgery( MICS) previously. Even after the introduction, different ideas (Chordalizer, COR-KNOT, special long CP cannula, de-air technique, etc.) were developed. As a result of the learning curve, more stable surgery could be performed. However, keeping in mind that RACS is only a means and not a purpose, the RACS indication should always be carefully considered. When problems, such as intracardiac manipulation or uncontrollable bleeding, occur, safe surgery must be decided to switch to normal thoracotomy as soon as possible. A further enhancement would be expected for even better results and expansion of the RACS indications.

Virtual reality-guided aortic valve leaflet reconstruction for type 0 bicuspid aortic stenosis

Although virtual reality (VR) techniques that enable visualizing a patient's anatomy stereoscopically have been developed recently, these techniques are still scarcely used in clinical settings, and their benefits remain uncertain. Herein, we demonstrate how VR preoperative planning facilitated the efficiency of a complex surgical procedure. A 53-year-old male was diagnosed as type 0 bicuspid aortic stenosis. To take haemodynamical advantage and to lower valve-related reoperation risks, an aortic valve reconstruction was scheduled; however, anatomical tri-leaflet neocuspidalization for type 0 bicuspid aortic root is particularly challenging. To optimize the procedure, VR preoperative planning was applied to create a blueprint of the aortic root rearrangement and suture line design. This allowed for a competent aortic valve to be reconstructed speedily, resulting in an excellent postoperative course.

A simple technique of artificial chordae implantation in robotic cardiac surgery using a novel tube device supporting expanded polytetrafluoroethylene chordae ligation

Artificial chordae implantation is an important technique for treating leaflet lesions in mitral valve repair. Considering that the expanded polytetrafluoroethylene (ePTFE) suture is slippery on the surface, adequate ligation without laxity should be critically considered, especially in robotic surgery. To resolve this issue, we applied a novel device that controls the length of an ePTFE suture (Chordarizer) for artificial chordae implantation in robotic mitral valve repair. After assessing the mitral valve via the right side of the left atrium, we stitched a CV-4 ePTFE suture to the target papillary muscle. Using a calliper, we measured the length of the artificial chordae and passed the CV-4 through the appropriate Chordarizer. Then, we stitched the CV-4 to the tip of the leaflet from the left ventricle side and tied it using da Vinci arms. Finally, the Chordarizer was peeled away. Chordarizer ensured safe and reliable artificial chordae implantation procedures with robotic mitral surgery, by maintaining the desired CV4 length.

Aortic valve replacement and coronary artery bypass grafting through a right thoracotomy for a patient with a left chest wall tumor

A 68-year-old man was diagnosed with severe aortic stenosis and right coronary artery occlusion on preoperative examination for total extirpation of a giant left breast liposarcoma. Prior to the intervention for the liposarcoma, he underwent successful aortic valve replacement and coronary artery bypass grafting via a right anterolateral thoracotomy to avoid the tumor close to the sternum. On postoperative day 28, the patient underwent a successful wide excision of the left chest wall tumor.

[Simultaneous Surgery of Gastrectomy and Rerouting of the Pre-existing Right Gastroepiploic Artery Bypass Graft for Gastric Cancer]

The patient was a 76-year-old man with advanced gastric cancer who had a history of coronary artery bypass grafting using the right gastroepiploic artery. Although coronary angiography confirmed the patency of all the coronary artery bypass grafts, his right gastroepiploic artery was required to be cut for curative gastrectomy. To prevent serious myocardial ischemia, rerouting of the right gastroepiploic artery graft was performed using a saphenous vein graft via right mini-thoracotomy. The proximal end of the saphenous vein graft was anastomosed to the ascending aorta. Then, gastrectomy via epigastric median re-laparotomy was performed. His postoperative course was uneventful.

[Usefulness of Balloon Aortic Valvuloplasty for Determining the Operative Procedure in a Patient with Severe Aortic Stenosis Complicated with Secondary Mitral Regurgitation;Report of a Case]

A 59-year-old man on chronic hemodialysis presented with severe aortic stenosis(AS) and moderate mitral regurgitation (MR). Although aortic valve replacement was scheduled, his status deteriorated into New York Heart Association(NYHA) class III heart failure due to the exacerbation of AS and concomitant MR. Double valve replacement was considered to be too high risk for the patient, and balloon aortic valvuloplasty(BAV) was initially performed. As a result, the mean pressure gradient of the aortic valve decreased from 65 to 28 mmHg and the mean pulmonary pressure also from 52 to 33 mmHg. Furthermore, MR improved from severe to moderate following BAV. We considered the alleviation of aortic stenosis was sufficient treatment for the patient. He underwent aortic valve replacement on the following day of BAV. Postoperative echocardiogram after 1 month showed mild MR, and the estimated pulmonary systolic pressure was 35 mmHg. During the 1-year follow up, MR was not aggravated. BAV might be a useful diagnostic method to determine the operative strategy for severe AS complicated with secondary MR.

Coronary Artery Assessment by Epicardial Pulsed Doppler Ultrasound

An intraoperative method was developed for direct investigation of the coronary arteries using an epicardial high-frequency two-dimensional Doppler ultrasound transducer. This fingertip 7.5-MHz transducer was used in 30 patients undergoing coronary artery bypass surgery to measure blood flow in the coronary arteries and bypass grafts. In all the patients, clear images of the coronary arteries and the bypass grafts were obtained in the beating heart, and coronary blood flow could be measured to evaluate the degree of stenosis. There were no significant differences between the measurements obtained with the Doppler transducer and a transit-time ultrasonic flowmeter of blood flow in the left internal thoracic artery graft to the left anterior descending coronary artery, indicating that the Doppler method produces accurate and reproducible measurements. This method can provide useful intraoperative information about the coronary artery system in emergency operations such as acute aortic dissection.

Mitral-Aortic Intervalvular Pseudoaneurysm with Ventricular Septal Defect

A 35-year-old woman was found on echocardiography to have a pseudoaneurysm of the mitral-aortic intervalvular fibrosa, residual ventricular septal defect, and aortic regurgitation. She had undergone surgical closure of a ventricular septal defect at age 7 and was found to have residual shunt several years later. She had been followed nonsurgically and had symptoms of cardiac failure during her 2 pregnancies. The pseudoaneurysm and the septal defect were successfully repaired.

Reconstruction of aorto-mitral continuity with a handmade aorto-mitral bioprosthetic valve for extensive bivalvular endocarditis

Surgical treatment is effective to exclude all infected tissue in patients with infective endocarditis. Although various techniques have been reported, it has remained a great challenge for patients with extensive infected regions. A patient with extensive bivalvular endocarditis including the aortic and mitral valve and aorto-mitral continuity is described. A handmade aorto-mitral bioprosthetic valve was created to reconstruct the defect after extensive debridement. The patient was discharged on the 30th postoperative day without inflammatory signs.

Simple and safe graft insertion in the elephant trunk technique

The elephant trunk technique is a well-established procedure, but aortic wall injury or aneurysmal rupture may occur if the graft is forcibly pushed to insert it into the distal aorta. We have developed simple and safe insertion technique using a syringe.

Mitral valve repair in a patient with acromegaly

We report on a successful mitral valve (MV) repair and modified Cox maze procedure in a 35-year-old male patient with acromegaly, associated with severe mitral regurgitation and atrial fibrillation. He underwent a transsphenoidal adenomectomy, 7 months after the cardiac operation, and IGF-I level was normalized postoperatively. Valvular disease in patients with acromegaly is associated with hormonal activity, and control of growth hormone and insulin-like growth factor I excesses is important in the long-term durability of mitral valve repair.

Significance of mitral valve repair for active-phase infective endocarditis

Mitral valve repair is preferred to replacement in infective endocarditis, but in the active phase, it often requires extensive debridement of infected tissue and complex reconstruction. We investigated 22 consecutive native mitral valve operations during active-phase infective endocarditis. The time from initiation of medical treatment to operation was 16.8 ± 16.4 days. Mitral valve repair was performed in 15 (68.2%) patients, using prosthetic annuloplasty in 14, an autologous pericardial patch in 11, and artificial chordal replacement in 9. Hospital mortality was 9.1% (2 patients), due to subarachnoid hemorrhage and pneumonia. One patient died 26 months after valve replacement due to congestive heart failure. The postoperative left ventricular end-diastolic dimension was significantly smaller (45.7 ± 5.6 vs. 53.3 ± 10.2 mm) and ejection fraction was significantly higher (57.0% ± 14.7% vs. 40.1% ± 8.2%) in patients who underwent valve repair compared to those who had valve replacement. Mitral regurgitation requiring reoperation occurred in 3 patients during follow-up. Mitral valve repair is feasible in active-phase infective endocarditis, and results in improved regression of left ventricular dimensions compared to valve replacement. However, complex mitral valve repair with extensive leaflet resection may not have long-term durability.

Aortic valve replacement in a patient with alpha-thalassemia

Cardiac valve disease resulting from elastic tissue defects has been demonstrated in patients with beta-thalassemia; however, valve disorders of patients with alpha-thalassemia have been rarely discussed. We present the case of a patient with alpha-thalassemia and severe aortic regurgitation with left ventricular dysfunction. The patient underwent successful aortic valve replacement with mechanical prosthesis. Histopathology of the excised valve showed elastic tissue disruption and chronic thrombus on the ventricular side. Hypercoagulative states have been observed in patients with alpha-thalassemia as beta-thalassemia; therefore special attention should be taken in perioperative anticoagulation therapy.

Large primary cardiac sarcoma on the left ventricular free wall: is total excision contraindicated?

A case of a large primary cardiac sarcoma on the left ventricular free wall is reported. Although the definitive diagnosis of this tumor was not made preoperatively, total excision was planned for rapid diagnosis and optimal procedure. However, the operation was discontinued due to intraoperative diagnosis of malignancy. As a result, the patient suffered from the symptoms of cardiac tamponade caused by the large tumor. We discuss the surgical strategy to provide therapeutic benefit for possible patients in the future. In conclusion, an aggressive attempt at volume reduction such as cardiac autotransplantation may relieve the symptoms, even though such surgery would only be palliative.

Hypothermic Circulatory Arrest: Renal Protection by Atrial Natriuretic Peptide

Moderate hypothermic circulatory arrest with selective cerebral perfusion has been developed for cerebral protection during thoracic aortic surgery. However, visceral organs, particularly the kidneys, suffer greater tissue damage under moderate hypothermic circulatory arrest, and acute renal failure after hypothermic circulatory arrest is an independent risk factor for early and late mortality. This study investigated whether atrial natriuretic peptide could prevent the reduction in renal perfusion and protect renal function after moderate hypothermic circulatory arrest. Twelve pigs cooled to 30°C during cardiopulmonary bypass were randomly assigned to a peptide-treated group of 6 and a control group of 6. Moderate hypothermic circulatory arrest was induced for 60 min. Systemic arterial mean pressure and renal artery flow did not differ between groups during the study. However, renal medullary blood flow increased significantly in the peptide-treated group after hypothermic circulatory arrest. Myeloperoxidase activity was significantly reduced in the medulla of the peptide-treated group. Renal medullary ischemia after hypothermic circulatory arrest was ameliorated by atrial natriuretic peptide which increased medullary blood flow and reduced sodium reabsorption in the medulla. Atrial natriuretic peptide also reduced the release of an inflammatory marker after ischemia in renal tissue.

[The malignant tumor of the pulmonary artery; report of a case]

Primary sarcoma of the pulmonary artery is rare. Diagnosis is difficult and often delayed; pulmonary embolism is part of the differential diagnosis. We treated a 46-year-old woman with progressive dyspnea. Computed tomography showed a lesion occupying the main pulmonary artery and peripheral branches on both sides. The pulmonary artery tumor, resected under cardiopulmonary bypass, was diagnosed pathologically as intimal sarcoma. Two weeks after the operation, the patient was feeling well and discharged from our hospital. Although the prognosis of pulmonary artery sarcoma is poor, early diagnosis and resection may prolong survival.

[Quality of life of long-term survivors of surgically treated lung cancer]

Quality of life (QOL) of long-term survivors (more than 3 years after surgery) of primary non-small cell lung cancer was studied. QOL was analyzed using European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, 30-Item version 3.0 (QLQ-C30) and Hospital Anxiety and Depression Scale (HADS). Sixty of 91 patients (66%) participated in this study 87 +/- 5 (38-172) months postoperatively. In QLQ-C30, calculated scores of physical (84.0 +/- 2.4), role (81.3 +/- 3.6), cognitive (79.7 +/- 2.6), emotional (86.8 +/- 1.9), and social (91.0 +/- 1.9) functioning, and global QOL (72.6 +/- 2.9) were obtained. Calculated HADS A (anxiety) was 3.3 +/- 0.3 and HADS D (depression) was 4.0 +/- 0.4. Postoperative follow-up duration was correlated with financial impact only. QOL of long-term survivors was influenced by gender histology, marital status, employment status, and academic carrier.

Isthmus of a horseshoe kidney overlying a ruptured abdominal aortic aneurysm: a case report

Horseshoe kidney is a rare congenital anomaly showing various degrees of fusion and accessory blood supply. Coexistence of horseshoe kidney and aortic aneurysm therefore presents a technical challenge to vascular surgeons. We report an 83-year-old woman with a ruptured abdominal aortic aneurysm associated with horseshoe kidney. Preoperative computed tomography (CT) showed discontinuity of the aneurysm wall in relation to the isthmus of the horseshoe kidney, and rupture of the aneurysm into the retroperitoneal space. The aneurysm was exposed via a transperitoneal approach, and grafting was performed successfully together with division of the isthmus of the horseshoe kidney. Renal function showed no impairment postoperatively.

Anastomosis of an anomalous segmental vein with the azygos vein in living-donor lobar lung transplantation

We report the case of a living-donor lobar lung transplantation in which we found an abnormal segmental vein in the right lower lobe of the donor lung. The abnormal vein was anastomosed to the azygos vein of the recipient so that lung edema and congestion could be avoided. This alternative technique is effective in living-donor lobar lung transplantation when the superior segmental vein in the right lower lobe of the donor drains into the superior vein.

Total right ventricular exclusion improves left ventricular function in patients with end-stage congestive right ventricular failure

BACKGROUND

We developed a total right ventricular (RV) exclusion procedure for the treatment of isolated congestive RV failure. The objective of the present study was to elucidate the effects of a complete removal of RV volume overload (RVVO) on the surgically created single left ventricle (LV).

METHODS AND RESULTS

Three adults (2 arrhythmogenic RV dysplasia, 1 Ebstein) and 5 children (all Ebstein) in NYHA class IV underwent the procedure. The RV free wall was resected from the heart, and the tricuspid orifice was closed. Pulmonary blood supply was obtained by a cavopulmonary connection in 6 patients and a systemic-pulmonary shunt in 2. The LV function was evaluated by 2-dimensional echocardiography 1 month after the surgery. All patients are alive. The paradoxical movement of the interventricular septum and geometry of the LV expressed by its eccentricity (2.1 to 1.2, P<0.01) were normalized after the operation in all 8 patients. LV end-diastolic volumes (59% to 109% of normal value, P<0.01), indexed maximal left atrial area (6.5 to 10.5 cm2/m2, P<0.01), LV ejection fraction (27% to 62%, P<0.01), and cardiac index (2.1 to 3.3 L/min/m2, P<0.05) all significantly increased.

CONCLUSIONS

Removal of the RVVO by means of the total RV exclusion procedure provides effective volume loading, restores a cylindrical shape, and improves contractile function of the LV, thus leading to increased systemic output.

Living-donor lobar lung transplantation for various lung diseases

OBJECTIVE

We report on our early experience in living-donor lobar lung transplantation for patients with various lung diseases including restrictive, obstructive, septic, and hypertensive lung diseases.

METHODS

From October 1998 to March 2002, living-donor lobar lung transplantation was performed in 14 patients with end-stage lung diseases. There were 11 female patients and 3 male patients, with ages ranging from 8 to 53 years, including 4 children and 10 adults. Diagnoses included primary pulmonary hypertension (n = 6), idiopathic interstitial pneumonia (n = 2), bronchiolitis obliterans (n = 2), bronchiectasis (n = 2), lymphangioleiomyomatosis (n = 1), and cystic fibrosis (n = 1). Bilateral living-donor lobar lung transplantation was performed in 13 patients and right single living-donor lobar lung transplantation was performed for a 10-year-old boy with primary pulmonary hypertension.

RESULTS

All the 14 patients are currently alive with a follow-up period of 4 to 45 months. Although their forced vital capacity (1327 +/- 78 mL, 50.2% of predicted) was limited at discharge, arterial oxygen tension on room air (98.5 +/- 1.8 mm Hg) and systolic pulmonary artery pressure (24.8 +/- 1.6 mm Hg) were excellent. Forced vital capacity improved gradually and reached 1894 +/- 99 mL, 67.4% of predicted, at 1 year. All donors have returned to their previous lifestyles.

CONCLUSIONS

Living-donor lobar lung transplantation can be applied to restrictive, obstructive, septic, and hypertensive lung diseases. This type of procedure can be an alternative to conventional cadaveric lung transplantation for both pediatric and adult patients who would die soon otherwise.

Reversal of chronic cyclosporine nephrotoxicity after heart transplantation-potential role of mycophenolate mofetil

BACKGROUND

Chronic cyclosporine nephrotoxicity (CCN) after heart transplantation is a progressive condition that may lead to end-stage renal failure. The extent to which CCN is reversible with reduction or withdrawal of cyclosporine therapy is unknown. The aim of this study was to assess the reversibility of CCN and to assess the safety and efficacy of a strategy of cyclosporine dosage reduction, combined with conversion from azathioprine to mycophenolate mofetil (AZA/MMF switch) to maintain immunosuppression.

METHODS

An AZA/MMF switch followed by cyclosporine dose reduction was undertaken in 30 heart transplant recipients (23 men, 7 women; mean age, 54 +/- 2 years) with established CCN at a mean of 90 +/- 9 months after transplantation (range, 17-182 months). The mean maintenance MMF dosage was 2.3 +/- 0.1 g/day (n = 28). Mean cyclosporine dosage was decreased from 2.3 +/- 0.2 mg/kg/day before AZA/MMF switch to 1.6 +/- 0.2 mg/kg/day.

RESULTS

Three patients (10%) were withdrawn from MMF, 2 because of diarrhea and the third because of severe pneumonia that developed within 2 weeks of AZA/MMF switch. All 3 were restabilized with AZA. One patient (4%) experienced acute rejection 7 months after AZA/MMF switch. This resolved after an oral pulse of prednisolone. Systemic infections occurred in 6 patients within 12 months of AZA/MMF switch. Actuarial survival 1 year after AZA/MMF switch was 86% +/- 6%. One patient died of infection and 3 of other causes. Serum creatinine concentration decreased from 248 +/- 15 micromol/liter before cyclosporine dosage reduction to 193 +/- 11 micromol/liter and 206 +/- 19 micromol/liter at 3 and 12 months after dosage reduction (both p < 0.01 versus baseline, n = 23). Of the 23 patients who remained on MMF at 12 months, a decrease in serum creatinine was documented in 19 (83%). Four patients showed no improvement or showed deterioration in renal function, and three of these progressed to end-stage renal failure.

CONCLUSIONS

Chronic cyclosporine nephrotoxicity has a significant reversible component in most patients. A strategy of AZA/MMF switch combined with cyclosporine dosage reduction is generally well tolerated and results in short-term improvement in renal function in most patients. Close vigilance is required during the first 12 months after AZA/MMF switch because both acute rejection and infection may occur.

The Cox maze iii procedure: parallel normalization of sinus node dysfunction, improvement of atrial function, and recovery of the cardiac autonomic nervous system

OBJECTIVE

The Cox maze III procedure includes isolation of the pulmonary veins and multiple incisions in both atria in what corresponds to partial autotransplantation and partial denervation of the heart. The aim of this prospective longitudinal study was to identify physiologic effects of reinnervation on changes in heart rate at rest and in response to various stimulations and on atrial function after the Cox maze III procedure.

PATIENTS AND METHODS

Power spectral analysis of heart rate variability, exercise testing, 24-hour Holter monitoring, electrocardiography, and transthoracic and transesophageal echocardiography were performed in 30 adult patients after the combined Cox maze III procedure and mitral valve surgery (maze group). They were prospectively followed up at 1, 3, 6, and 12 months after the operation. The results were compared with those of 15 heart transplant recipients (transplant group) and normal probands (healthy adults, n = 12).

RESULTS

The physiologic effects of denervation with no differences in cardiac autonomic activity between the groups were seen early after the operation. Later, evidence of autonomic reinnervation was observed only in the maze group but not in the transplant group. Inappropriate heart rate responses during physical exercise were clearly evident in both groups after 1 and 3 months, with progressive improvement seen between 6 and 12 months only in the maze group. Left atrial function after the Cox maze procedure improved parallel to the recovery of sinus node function.

CONCLUSION

Progressive improvement of sinus node function and atrial contractions with significant functional normalization 1 year after the Cox maze procedure corresponded to functional reinnervation and recovery of the autonomic nervous system.

Influences of bilateral endoscopic transthoracic sympathicotomy on cardiac autonomic nervous activity

OBJECTIVES

Endoscopic transthoracic sympathicotomy (ETS) is a minimal invasive procedure of thoracic sympathetic blockage. The purpose of this study was to evaluate cardiac autonomic nervous activity after ETS in order to confirm the reliability and safety of ETS.

METHODS

A series of electrophysiological studies were performed before and 1 week after bilateral 2nd and 3rd thoracic sympathicotomy in 13 patients with primary palmar hyperhydrosis. Palmar perspiration was measured under sympathetic stress, and body surface mapping was recorded in a supine position. In the head-up tilt test of 0, 30, 60 and 90 degrees, corrected QT interval (QTc) and T wave amplitude (Twa) were assessed. The power spectral analysis of heart rate variability was processed to attain power values of the low-frequency (0.04-0.15 Hz), the high-frequency (0.15-0.40 Hz) and the low/high frequency ratio.

RESULTS

In all patients, the perspiration response on the palm to sympathetic stimulation was completely inhibited after ETS. Isointegral mapping revealed that ETS altered electroactivity on the heart. In the head-up tilt study, R-R intervals significantly increased after the surgery in the head-up tilt positions (P < 0.05), although there was no significant difference in the supine position. There is no significant difference in QTc and Twa before and after the surgery, both in the supine and the head-up tilt positions. There was no significant difference in the LF or HF before and after surgery, either in the supine position or the head-up tilt positions. In the LF/HF, there was no significant difference before and after surgery in the supine position. However, the LF/HF in the head-up tilt positions was significantly decreased after surgery (P < 0.05). Sympathetic suppression of ETS was recognized more obviously under the steeper head-up tilt positions.

CONCLUSIONS

The influences on the cardiac autonomic nerve system of the ETS of upper thoracic sympathetic nerve were seen to be of a lesser degree at rest. However, the response to sympathetic stimulation was suppressed after the surgery.

Transient sinus node dysfunction after the Cox-maze III procedure in patients with organic heart disease and chronic fixed atrial fibrillation

OBJECTIVES

This prospective study examined types, frequency and time dependency of the electrophysiologic manifestation of the sinus node dysfunction after the Cox-maze III procedure--the technique of choice for the management of medically refractory atrial fibrillation-in patients with organic heart disease, chronic fixed atrial fibrillation and no preoperatively overt dysfunction of the sinus node.

BACKGROUND

The original maze procedure was modified twice in order to reduce the high incidence of the sinus node inability to generate an appropriate sinus tachycardia in response to maximal exercise, and occasional left atrial dysfunction. Despite these modifications, postoperative disturbance of sinus node function can be frequently observed.

METHODS

In 15 adult patients, standard electrocardiogram, 24-h Holter monitoring, power spectral analysis of heart variability, exercise testing, Valsalva maneuver and rapid positional changes were performed 3, 6 and 12 months after the Cox-maze III procedure and mitral valve surgery or closure of atrial septal defect.

RESULTS

Electrocardiographic manifestations of sinus node dysfunction were identified in 12 patients at 3 months, in 6 patients at 6 months, and in 0 patients at 12 months after surgery. The heart rate response to exercise during the first 6 months was reduced in the maze group and became fully normal at 12 months. Power spectral analysis of heart rate variability showed very low power values at 1 month with inhibited cardiac autonomic activity and no response on sympathetic stress. A potential of recovery of cardiac autonomic activity was documented 12 months after surgery.

CONCLUSIONS

The manifestations of sinus node dysfunction following the Cox-maze III procedure were time dependent and their frequency and intensity progressively decreased and disappeared within 12 months after surgery.

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device

BACKGROUND

Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated.

METHODS

An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance.

RESULTS

In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01).

CONCLUSIONS

The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

[Surgical technique of endoscopic transthoracic sympathicotomy: axillary approach]

A total of 181 endoscopic transthoracic sympathicotomy were performed at our hospital from December, 1992 to March, 1997. After single-lumen endotracheal intubation for general anesthesia, the patient was placed in half sitting position. A small (1 cm) incision was made in the anterior axillary line through the third intercostal space and an apical pneumothorax was created by insufflation of 1.8 L of CO2 in the pleural cavity through a Surgineedle. A 24 Fr. urological transurethral electroresectoscope was introduced through the same incision. The sympathetic chain could be observed through parietal pleura riding on the costovertebral junctions. In palmar hyperhidrosis the second and third thoracic sympathetic ganglia were electrocoagulated. In axillary hyperhidrosis the forth ganglion was included. The lung was expanded by limiting expiration and sucking CO2. The operation was repeated on the other side. Endoscopic transthoracic sympathicotomy was an efficient, safe and low invasive surgical procedure for the treatment of palmar, axillary hyperhidrosis, Raynaud's disease and Buerger disease.

[Endoscopic transthoracic sympathectomy for angina pectoris: a case report]

We performed endoscopic transthoracic sympathicotomy (ETS) for angina pectoris in a 77-year-old female. She had multiple coronary disease of a history of failed percutaneous transluminal coronary angioplasty (PTCA). Bilateral ETS of Th2 to Th5 was carried out under general anesthesia without surgical complication, hemodynamic change and ECG change. Postoperatively she was free from angina and increased working capacity. ST depression on ECG was remarkably improved and the increase of heart rate and systolic blood pressure was suppressed on exercise test after a month of ETS. The effect of ETS to angina pectoris was suspected not to relieve anginal pain but also to reduce myocardial oxygen demand on exercise. We conclude that ETS is a safe, simple and low invasive procedure and it can be done in patients who are judged unsuitable for coronary artery bypass grafting (CABG) or PTCA.

Is internal thoracic artery grafting suitable for a moderately stenotic coronary artery?

Grafting an internal thoracic artery to a coronary artery with moderate stenosis remains controversial. Competitive flow from the native coronary artery has been proposed as the cause of distal narrowing and ultimate failure of the internal thoracic artery graft. We investigated intraoperative phasic blood flow in internal thoracic arteries grafted to coronary arteries with various degrees of stenosis and the influence of stenosis on postoperative angiographic findings. One hundred patients who underwent coronary artery bypass grafting of an internal thoracic artery to the left anterior descending coronary artery were divided into three groups according to degree of coronary stenosis. Group 1 included 39 patients who had 75% or less stenosis, group 2 included 34 patients with stenosis from 76% to 90%, and group 3 included 27 patients with stenosis greater than 90%. Mean flow and peak systolic flow of internal thoracic artery graft in group 1 were lower than those in group 2 (p < 0.01, p < 0.05). Peak diastolic flow in group 1 showed no difference from flows in groups 2 and 3. In eight patients in group 1, internal thoracic artery flow showed a predominant diastolic peak with characteristic systolic reversal as a result of competitive flow from the native coronary artery. Angiography at 1 month showed that the internal thoracic artery graft was patent in every case. Relative contributions of native coronary artery and internal thoracic artery flow to distal perfusion differed among the three groups (p < 0.001). In group 1, 15% of patients showed native-dominant flow, 62% showed balanced flow, and 23% showed internal thoracic artery-dependent flow. In group 2, 9% of patients showed native-dominant flow, 29% showed balanced flow, and 62% showed internal thoracic artery-dependent flow. In group 3, 96% of patients showed internal thoracic artery-dependent flow. String sign of the internal thoracic artery graft developed in only three patients; in two of these patients internal thoracic arteries were grafted to coronary arteries with stenosis of 50% or less and in the other patient there was competitive flow from a diagonal vein graft. Eleven of 13 internal thoracic arteries grafted to coronary arteries with stenosis of 50% or less did not show string sign. Competitive flow from a moderately stenotic coronary artery did not predispose the patient toward string sign of the internal thoracic artery graft in the presence of substantial diastolic internal thoracic artery flow. We conclude that internal thoracic artery grafting is acceptable for a moderately stenotic coronary artery.

Internal thoracic artery graft function during exercise assessed by transthoracic Doppler echography

BACKGROUND

Noninvasive quantitative assessment of internal thoracic artery (ITA) graft function at rest and during exercise is important in patients who have undergone coronary artery bypass grafting.

METHODS

Blood flow in the ITA graft was measured using transthoracic color Doppler echography before and after operation in 50 patients who underwent coronary artery grafting using an ITA to the left anterior descending artery. The patients were divided into three groups according to the degree of coronary stenosis and previous anterior myocardial infarction: Group 1 included 12 patients with severe (90% or more) coronary stenosis accompanied by anterior infarction. Group 2 included 26 patients with severe coronary stenosis without anterior infarction. Group 3 included 12 patients with moderate (75% or less) coronary stenosis without anterior infarction. Transthoracic echographic images of the ITA were obtained through the first intercostal space using a 7.5-MHz probe, and the diameter and cross-sectional area of the ITA were measured on B-mode imaging. Systolic, diastolic, and mean blood flow velocity and volume were measured by the Doppler method.

RESULTS

Internal thoracic artery diameter increased significantly from 2.2 mm to 2.4 mm after operation. The ITA flow patterns in both flow velocity and volume changed from systolic-dominant to diastolic-dominant after operation. Postoperative ITA graft flow was 82 +/- 24 mL/min, 53 +/- 30 mL/min, and 31 +/- 15 mL/min (p < 0.01, group 1 versus 3; p < 0.05, group 1 versus 2) and percent diastolic fraction of ITA flow was 72%, 68%, and 62% (not significant) in groups 1, 2, and 3, respectively. Compared with intraoperative ITA flow, which was measured using an ultrasound transit-time flowmeter, postoperative ITA graft flow was increased in group 1, but not changed in group 2 or 3. The ITA graft flow was measured before and after exercise in 19 patients and was compared with ITA flow in 10 normal control subjects. The ITA graft flow increased significantly with exercise in all patients in the three groups. Percent diastolic fraction of ITA flow increased significantly with exercise in patients with severe coronary stenosis (groups 1 and 2), but decreased significantly in patients with moderate stenosis (group 3).

CONCLUSIONS

Changes in native coronary artery and ITA graft may be predicted by assessing ITA flow pattern during exercise. Transthoracic color Doppler echography is a clinically useful noninvasive method of assessing ITA graft function at rest and during exercise.