Aortic valve replacement through left thoracotomy after esophageal operation.

A 67-year-old man was referred for aortic valve surgery due to aortic valve regurgitation. He underwent an aortic valve replacement through a left thoracotomy, since he had a history of esophageal surgery with substernal gastric tube reconstruction and lymph node dissection through a right thoracotomy 14 years ago. The aortic valve was successfully replaced with excellent visualization using vacuum-assisted venous drainage on a cardiopulmonary bypass. Although exposing the aortic valve through a left thoracotomy is difficult, the application of vacuum-assisted venous drainage helps visualize the aortic valve in this approach.

Recommendation for appropriate use of GRF glue in the operation for acute aortic dissection.

BACKGROUND: Because an excessive use of activator (formaldehyde + glutaraldehyde) is supposed to be responsible for later adverse events after the use of gelatin resorcin formalin (GRF) glue in surgery for acute aortic dissection, we have tried to use a minimum dose of activator when the GRF glue was applied. We compare our midterm surgical results for acute aortic dissection with and without the use of GRF glue. METHODS: Forty-nine consecutive operated cases with Stanford type A acute aortic dissection within 48 h from onset from 1992 to 2005 were retrospectively analyzed. GRF glue was used in 21 cases (18 proximal and 14 distal anastomosis sites) since 1995 with outer felt reinforcement (GRF group). RESULTS: There was no operative deaths. In-hospital mortality was 4.8% in the GRF group and 7.1% in the control group (P = 0.7308). Intraoperative blood loss and transfusion requirements were similar between groups. The patency of the distal false lumen after the operation (57% vs. 55%, P = 0.8855), the 3-year survival estimate (82% +/- 10% vs. 92% +/- 6%, P = 0.4219), and the 3-year actuarial freedom from a reoperation of 92 anastomoses (97% +/- 3% vs. 100%, P = 0.4986) were similar between the GRF group and the control group, respectively. A multivariate Cox's proportional hazard model identified no significant predictor for midterm death or reoperation. CONCLUSIONS: The use of GRF glue for type A acute aortic dissection seems as clinically safe as other options with regard to midterm death or reoperation when applied appropriately with felt reinforcement.

Wavelet analysis of valve closing sound detects malfunction of bileaflet mechanical valve.

Several studies have reported the asynchronous closure of normal bileaflet valves (NBVs), resulting in a split in its closing sound; however, the clinical significance of this split has never been studied in malfunctioning bileaflet valves (MBVs). The study comprised 218 valves in 184 patients, including normal monoleaflet valves (n = 10), NBVs (n = 198), and MBVs (n = 10). Valve function was confirmed by cinefluoroscopy prior to analysis of the valve sound by the Morlet continuous wavelet transform (CWT). The split interval (SI) for each heartbeat was measured, and the coefficient of variation (CV) of its mean (valve SI) was calculated as a parameter for the fluctuation of the SI. The CWT of monoleaflet valves showed a single spike, whereas NBVs exhibited a clear split. There was no significant difference in valve SI between the aortic and mitral positions; however, the mean of the CV was significantly greater in the mitral position (n = 90, 0.507 +/- 0.254) than in aortic position (n = 108, 0.353 +/- 0.228, P = 0.000045). The split was not found in six (aortic; three, mitral; three) of ten patients with MBVs. The other four patients had a distinct split, but the CV was significantly lower for MBVs (0.138 +/- 0.105) than for NBVs (0.343 +/- 0.221, P = 0.042). Receiver-operating characteristics analysis demonstrated the cutoff line of the CV to be 0.112 for detecting malfunctioning aortic valves with the highest accuracy of 86.1%. This new system using the Morlet CWT can detect MBVs. It will be a useful modality for screening the function of bileaflet valves.

Off-pump aortic arch repair through a median sternotomy for type B interrupted aortic arch with single ventricle physiology.

BACKGROUND: The aortic arch repair for interrupted aortic arch (IAA) with the hypoplastic ascending aorta through a median sternotomy requires cardiopulmonary bypass (CPB), which is very invasive in neonates and complicates pulmonary artery banding (PAB) is staged repair. METHODS: A 22-day-old neonate with a type B IAA having a functional single ventricle underwent arch repair and PAB through a median sternotomy without CPB. A partial occlusion clamp could be placed on the ascending aorta without cerebral malperfusion and the descending aorta could be directly anastomosed to the ascending aorta in an end-to-side fashion under stable circulatory condition. Thereafter, the tight PAB was performed with a circumference of 23mm without any difficulty. RESULTS: The postoperative echocardiogram revealed no stenosis on the anastomotic site and the patient was discharged uneventfully. CONCLUSION: This approach is effective in neonates with IAA who require staged repair, and least invasive for them.

Management of vital organ malperfusion in acute aortic dissection: proposal of a mechanism-specific approach.

OBJECTIVE: We report our strategy for malperfusion accompanying acute aortic dissection, especially that involving the abdominal organs, which is based on the mechanism and includes percutaneous management. METHODS: From 1991 through October 2005, a total of 38 of 135 (28%) patients with acute dissection presented with organ malperfusion. Altogether, 31 had type A dissection. The involved vascular territories were coronary in 8, brain in 16, celiac and superior mesenteric in 6, renal in 10, and lower limb in 13. For the abdominal organs, the mechanisms of the malperfusion were classified into the aortic type (n = 3) and the branch type (n = 13). The branch type was further divided into the orifice type (n = 8) and distal type (n = 5). All but one patient with type A dissection underwent a central aortic operation with resection of the entry site. Revascularization of the ischemic organ was added by bypass grafting or direct reconstruction. Distal organ malperfusion accompanying type B dissection was treated by the mechanism-specific approach. That is, the aortic type was treated by surgical fenestration, whereas the branch type was treated by percutaneous stenting. RESULTS: The one hospital death (2.6%) was due to brain infarction. Although a central aortic operation alone successfully reversed aortic-type malperfusion in all three patients, it was not effective for branch-type malperfusion in five of six vascular territories. Surgical fenestration did not successfully reverse branch-type renal malperfusion in two patients. Percutaneous stenting was successful in all three vessels with branch-type malperfusion. CONCLUSION: Central aortic operation or fenestration is effective for aortic-type malperfusion, whereas the branch type may require stenting or bypass grafting.

Wavelet analysis of bileaflet mechanical valve sounds.

It has been reported that asynchronous leaflet closure in a bileaflet mechanical valve causes a split in the valve closing sound. We have previously reported that the continuous wavelet transform (CWT) with the Morlet wavelet as modified by Ishikawa (the Morlet wavelet) is the most suitable method among the CWTs for detecting a split in the bileaflet mechanical valve sound because this method can detect the highest frequency signal among the CWT methods with higher time resolution. This is the first article which discusses the acoustic properties of five types of bileaflet valves using the Morlet CWT. Similar behavior of the valve sound split intervals with wide fluctuations over consecutive heartbeats was found to be the common finding for all the bileaflet valves. This result suggests that fluctuation of the split interval proves the normal movement of both leaflets without movement disturbance. The mean differences in the split interval between these bileaflet valves were statistically significant, and the wavelet coefficients of the CWT showed characteristic scalographic patterns, such as a teardrop shape or a triangle beneath the split. However, these two findings gave no valuable information for the diagnosis of bileaflet valve malfunction. A split in the valve closing sound with a fluctuating interval was the common finding in these five normally functioning bileaflet valves, and careful observation of the split's behavior may be a key to diagnosis of bileaflet valve malfunction.

Apicoaortic valved conduit for a patient with porcelain aorta.

A 69-year-old woman had severe aortic stenosis with a circumferentially calcified aorta from the ascending aorta to the aortic arch, and moderately impaired left ventricular function. Implantation of an apicoaortic valved conduit was performed as aortic clamping was not feasible. The early results were excellent.

Proximal aortic replacement with ascending-descending bypass for a diffuse aneurysm: report of a case.

We performed successful ascending-arch aortic replacement and concomitant ascending-to-descending aorta bypass with exclusion of a descending thoracic aneurysm, via median sternotomy, for a ruptured aortic aneurysm involving the entire thoracic aorta. The patient was an 80-year-old man with cardiopulmonary dysfunction and a history of lung tuberculosis. This operation, which has been used for complex descending thoracic aortic lesions such as recoarctation, is a feasible option for a diffuse thoracic aortic aneurysm when single-stage repair is mandatory.

Bileaflet mechanical valve sound analysis using a continuous wavelet transform.

Bileaflet mechanical valve closing sounds have splits, the duration of which is not constant in normally functioning valves. However, no reports have discussed the influences of valve malfunction on the split interval, neither have any studies discussed the fact that mechanical valve closing sound signals must be analyzed using a time-frequency analysis because they are nonstationary signals. The continuous wavelet transform (CWT), a time-frequency analyzing method using mother wavelets modified by scale numbers, was selected in this study for analyzing bileaflet valve closing sounds because it is easy to understand and has no limitations such as the cross-terms in the Wigner-Ville distribution or the tradeoff between time and frequency resolutions of the short-time Fourier transform. This study compares the properties of the mother wavelets of various CWTs and selects one that is suitable for detection of the clear split in bileaflet mechanical valve closing sound signals. This article also establishes a standard frequency analyzing system for bileaflet mechanical valve sounds. A preliminary study with chirp Doppler signals for comparing the frequency properties of the mother wavelets of various CWTs suggested that Ishikawa's modified Morlet CWT has better time and frequency resolution at the highest frequency scale. Morlet/power CWT analysis of normal in vivo bileaflet valve closing sounds of the ST. Jude Medical (SJM), ATS, and Carbomedics (CM) valves demonstrated clear splits of very short interval at the highest level of frequency. Detection of the disappearance of the split by using this analytical method may be the key to identifying bileaflet mechanical valve malfunction in outpatient departments.

Novel technique for volume reduction of giant left atrium: simple and effective "spiral resection" method.

Despite some controversial studies, an enlarged left atrium has an impact on postoperative complications, and surgical correction should be considered, particularly in patients with a markedly enlarged left atrium. We present herein 2 patients with a giant left atrium (left atrial dimensions of 107 and 93 mm on echocardiograms), and describe an effective and simple procedure, the "spiral resection" method, to reduce any part of the dilated wall of the left atrium with a single incision.

[Novel stent/CEA strategy for patients with bilateral carotid artery stenosis and coronary artery disease: report of 2 cases].

Recently, there are increasing numbers of patients with occlusive carotid artery disease and coronary artery disease. Simultaneous or two-staged surgery for both lesions has been recommended for these patients to reduce the incidence of perioperative complications. However, therapeutic options for the patients with bilateral carotid artery stenosis and coronary artery disease have not been established. In this report, we describe two patients who successfully underwent carotid endarterectomy (CEA) and carotid artery stenting (CAS) on each carotid artery in parallel with coronary artery bypass grafts (CABG). A 49-year-old male with severe stenosis of the bilateral internal carotid artery (ICA) and heart failure underwent CAS on the right side. Next day, he successfully underwent CABG and CEA on the left side at the same time. A 62-year-old male with severe stenosis of the bilateral ICA and coronary artery disease underwent CAS on the right side and CEA on the left side with an interval of 7 days. Subsequently, CABG was performed uneventfully. No perioperative complication occurred in either patient. The results suggest that combination therapy of CAS and CEA would be a valuable option for patients with complex carotid/coronary artery diseases.

Postoperative renal function after elective abdominal aortic aneurysm repair requiring suprarenal aortic cross-clamping.

PURPOSE: To examine postoperative renal function after suprarenal aortic cross-clamping performed without renal hypothermia in patients undergoing elective abdominal aortic aneurysm (AAA) surgery. METHODS: Between 1991 and 2000, 18 patients underwent surgery for a juxtarenal AAA, which required a suprarenal aortic cross-clamp. All AAAs were repaired with a proximal anastomosis just below the renal arteries. We divided the patients into two groups according to the duration of the renal ischemia: <45 min (n = 12) and > or =45 min (n = 6). The postoperative changes in renal function were analyzed. RESULTS: There were no hospital deaths and none of the patients needed permanent hemodialysis. The postoperative peak in the serum creatinine level after suprarenal cross-clamping for > or =45 min was significantly higher than that after cross-clamping for <45 min. The percentage changes in serum creatinine and blood urea nitrogen were correlated positively with the duration of renal ischemia, and were significantly greater in the group with renal ischemia of <45 min than in the group with prolonged renal ischemia (> or =45 min). CONCLUSIONS: Suprarenal aortic cross-clamp without performing renal hypothermia is safe and able to be tolerated well by the patient during elective AAA surgery, although careful attention must be paid to limiting the period of renal ischemia.

Improved healing of small-caliber, long-fibril expanded polytetrafluoroethylene vascular grafts by covalent bonding of fibronectin.

PURPOSE: To evaluate the intermediate performance of small-caliber, long-fibril expanded polytetrafluoroethylene (ePTFE) vascular grafts pretreated with covalent bonding of fibronectin in dogs. METHODS: Small-caliber (4 mm), long-fibril (60 microm), ePTFE vascular grafts, 10 cm in length, were pretreated by covalent bonding of fibronectin. Bilateral iliac grafting was done in dogs using a fibronectin-bonded graft on one side and a nonbonded control graft on the other side. The grafts were retrieved 12 weeks after implantation, and subjected to histomorphometric analysis. RESULTS: Although the patency rates of the fibronectin-bonded and control grafts were the same (3/7, 43%), the fibronectin-bonded grafts showed almost complete neointimal healing, whereas the nonbonded control grafts showed only partial neointimal healing, proximally and distally. CONCLUSIONS: Small-caliber, long-fibril ePTFE vascular grafts with covalent bonding of fibronectin achieved almost complete neointimal healing by the time of retrieval at 12 weeks. This indicates that, with further modifications, our new technique for covalent bonding of fibronectin has great potential in the development of small-caliber arterial prosthetic grafts.

Surgical results for active endocarditis with prosthetic valve replacement: impact of culture-negative endocarditis on early and late outcomes.

OBJECTIVE: Surgical treatment of active infective endocarditis requires not only hemodynamic repair, but also special emphasis on the eradication of the infectious focus to prevent recurrence. This goal can be achieved by the combination of aggressive debridement of infective tissue and appropriate and adequate antibiotic treatment. We reviewed our experience with active endocarditis and identified factors determining early and late outcomes, particularly focusing on the factor of culture-negative endocarditis. METHODS: Sixty seven patients with clinical evidence of active endocarditis who underwent operation between 1991 and 2001 were evaluated. The aortic valve was infected in 28 (42%), the mitral valve in 23 (34%), and multiple valves in 16 (24%). Native valve endocarditis was present in 58 (87%) and prosthetic valve endocarditis in 9 (13%). Mean follow-up was 5.7 years (range, 0.2-11.5 years). RESULTS: Microorganisms were detected in 46 (69%): Staphylococcus aureus in 9 (13%), other staphylococci in 9 (13%), streptococcus species in 19 (28%), and others in 9 (28%), whereas 21 (31%) patients had culture-negative endocarditis. Operative mortality was 17.8% (12 patients). Reoperation was required in 8 (12%), while 3 late deaths (5.5% of hospital survivors) occurred. All events, including death, reoperation, periprosthetic leak, and recurrence of infection, occurred within 2 years after operation. Actuarial freedom from reoperation, late survival, and events at 5 years were 81.6, 76.4, and 68.6%, respectively. On multivariate analysis, no independent adverse predictor was detected for hospital death, whereas the following independent adverse predictors were identified: preoperative heart failure (P=0.0375), prosthetic valve endocarditis (P=0.0391) and culture-negative endocarditis (P=0.0354) for poor late survival; culture-negative endocarditis (P=0.0354) and annular abscess (P=0066) for poor event-free survival. Freedom from events was similar between patients with Staphylococcus aureus infection (3-year freedom 55.6%) and culture-negative endocarditis (3-year freedom 47.6%), whereas events were significantly low in patients with streptococcus infection (3-year freedom 100%). CONCLUSIONS: In our analysis, no independent adverse predictor was detected for hospital death; however, culture-negative endocarditis was identified as an independent predictor for both late survival and events after surgery. Event-free survivals were similar between staphylococcus infection and culture-negative endocarditis, and all events occurred within 2 years after operation, suggesting the necessity of close follow-up during that period.

Bilateral coronary ostial patch angioplasty with autologous pericardium in Takayasu arteritis: a case requiring replacement of the aortic valve and ascending aorta.

Since the lesions and stages of Takayasu arteritis vary with each patient, surgical treatment of this disease requires meticulous planning for the timing of operation, technique, material used, and postoperative medication. We report a rare complex lesion of Takayasu arteritis, which required simultaneous repairs for aortic regurgitation, a dilated ascending aorta and bilateral coronary ostial stenosis. Such multiple lesions have not been reported previously. A 47-year-old woman was referred to us because of heart failure and chest pain. The coronary ostial stenosis were enlarged with generously sized autologous pericardial patches, and separate aortic valve and ascending aortic replacements were performed since the diameter of the Valsalva sinus was 37 mm. The postoperative course was uneventful, but steroid therapy was commenced postoperatively because inflammatory reaction remained high.

Use of bioresorbable membrane to prevent postoperative small bowel obstruction in transabdominal aortic aneurysm surgery.

PURPOSE: To evaluate the efficacy of Seprafilm (Genzyme, Cambridge, MA, USA), a bioresorbable membrane, in preventing or reducing early postoperative small bowel obstructions after transabdominal abdominal aortic aneurysm (AAA) surgery. METHODS: Fifty-one patients underwent aortic reconstruction via a midline transperitoneal approach for infrarenal AAAs. Twenty-one patients underwent surgery with Seprafilm (Seprafilm group) and the remaining 30 patients did not (control group). The incidence of early small bowel obstruction was examined, and the time before liquid and solid diet were resumed was also compared to assess postoperative paralytic ileus. RESULTS: Patients in the Seprafilm group resumed a liquid diet on postoperative day (POD) 2.4 +/- 1.1 and a solid diet on POD 4.0 +/- 1.3, whereas the patients in the control group resumed a liquid diet on POD 3.3 +/- 1.9 and a solid diet on POD 5.4 +/- 3.4. These values were not significantly different between the two groups; however, the incidence of early postoperative small bowel obstruction was significantly lower ( P < 0.05) in the Seprafilm group (0/21) than in the control group (6/30). CONCLUSION: These findings suggest that Seprafilm may help to prevent early postoperative small bowel obstructions after transabdominal AAA surgery.

Relationship between fibril length and tissue ingrowth in the healing of expanded polytetrafluoroethylene grafts.

PURPOSE: To determine whether fibril length is correlated with graft healing as well as cellular and capillary ingrowth in a canine carotid implantation model. METHODS: Expanded polytetrafluoroethylene (ePTFE) vascular grafts with three different fibril lengths (30, 60, and 90 microm) were implanted into the carotid artery in dogs. They were retrieved 4 weeks later, and subjected to histomorphometric analysis. RESULTS: Endothelial healing was best in the 60-microm grafts. Not only cellular ingrowth but also capillary ingrowth was most evident in the 60-microm grafts, followed by the 90-microm grafts and then the 30-microm grafts. CONCLUSION: Better endothelial healing of ePTFE vascular grafts is correlated with more cellular and capillary ingrowth, but more cellular and capillary ingrowth is not correlated with longer fibril length or higher air porosity.

Left atrioventricular valve regurgitation after repair of incomplete atrioventricular septal defect.

BACKGROUND: Excellent surgical results have been reported for repair of incomplete atrioventricular septal defect; however, left atrioventricular valve regurgitation (ltAVVR) is a major cause of late morbidity. We reviewed our entire experience with incomplete atrioventricular septal defect in order to investigate long-term results of ltAVVR after repair and determine the factors influencing the progression of ltAVVR in late follow-up. METHODS: Between 1983 and 2002, 61 patients underwent surgical repair of incomplete atrioventricular septal defect, including 7 patients with intermediate forms. The age of operation ranged from 1 month to 62 years old (median 5.3 years old). Thirteen patients were less than 2 years old, including 7 infants, while there were 15 adult patients. All patients underwent patch closure of the ostium primum defect. Before 1995, the cleft was left open in 7 patients and partial closure of the cleft was done in 41 patients, whereas complete closure of the cleft was performed in 9 patients since 1996. Preoperative and postoperative ltAVVR at hospital discharge and late follow-up were graded 0-IV by echographic evaluation. RESULTS: There was 1 early death and 4 late deaths with a 91% 10-year actuarial survival rate. Preoperative ltAVVR grade was I in 25 patients, II in 31 patients, III in 4 patients, and IV in 1 patient. Postoperatively, ltAVVR deteriorated in 3 patients. Left AVVR decreased in 21 patients, whereas in 37 patients it remained the same at hospital discharge. Consequently, ltAVVR remained grade II in 18 patients, grade III in 2, and there was no patient with grade IV. During the long-term follow-up, 24 patients were noted to have increased ltAVVR, including grade III in 8 patients and grade IV in 4. Reoperations for ltAVVR were required in 5 patients (8.3% of hospital survivors); valve replacement in 3 patients and valve repair in 2. Actuarial freedom from reoperation for ltAVVR was 91% at 10 years, whereas actuarial freedom from postoperative ltAVVR grade III or more was 89% at 5 years and 78% at 10 years. Multivariate analysis indicated that postoperative ltAVVR grade II or more at hospital discharge (p = 0.0032, odds ratio = 7.41, 95%CI: 1.95-28.10) was the only independent variable related to late ltAVVR, whereas age at operation, preoperative grade of ltAVVR, and the method of cleft repair were not significant risk factors. CONCLUSIONS: Left AVVR is still a significant risk in long-term follow-up. Because the postoperative grade of ltAVVR is the only independent risk factor for late ltAVVR, more efforts should be focused on left atrioventricular valve repair so as to minimize residual regurgitation, even mild regurgitation.