Satoshi Ohsawa

Diagnostic Value of Cardiac CT in the Evaluation of Bicuspid Aortic Stenosis: Comparison With Echocardiography and Operative Findings

OBJECTIVE This study was conducted to assess the diagnostic value of cardiac CT for the evaluation of patients with bicuspid aortic valve disease. MATERIALS AND METHODS Fifty consecutive patients with aortic stenosis who underwent surgical valve repair between September 2005 and November 2006 were examined by ECG-gated CT and echocardiography. A 64-MDCT scanner was used. The image findings regarding the number of leaflets (bicuspid or tricuspid) were compared against the intraoperative findings and were statistically analyzed by one-way univariate analysis of variance. The aortic valve area (AVA) was also measured by CT and echocardiography, and the measured values were statistically compared by use of the paired Students t test. RESULTS Seventeen patients had a bicuspid aortic valve, and 33 had a tricuspid aortic valve. In 10 of the 50 patients, echocardiography was unable to depict the type of aortic valve because of extensive calcification. The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of a bicuspid aortic valve were 76.5%, 60.6%, 68.4%, and 95.2%, respectively, for echocardiography and 94.1%, 100%, 100%, and 97.1%, respectively, for CT. The CT findings were not significantly different from the intraoperative findings (p = 0.99), but the echocardiographic findings were (p < 0.05). The AVA measurements obtained by CT and echocardiography were 0.940 ± 0.44 cm(2) and 0.659 ± 0.234 cm(2), respectively, showing a significant difference (p < 0.05). CONCLUSION ECG-gated cardiac CT is useful for the accurate morphologic assessment of bicuspid aortic stenosis, especially in patients with severe valve calcification.

Postoperative renal function after an abdominal aortic aneurysm repair requiring a suprarenal aortic cross-clamp.

Abstract: We describe herein the postoperative renal functions of patients who required a suprarenal aortic cross-clamp during abdominal aortic surgery. Seven patients required a unilateral suprarenal aortic cross-clamp (group A) and six patients required a bilateral suprarenal clamp (group B). Eighty-three patients who required an infrarenal aortic clamp were assigned to group C. Renal hypothermia with renal perfusion or topical cooling during suprarenal clamp was not performed. No hospital deaths were encountered. In group B, the postoperative creatinine and blood urea nitrogen (BUN) levels remained statistically significantly higher than that of group C until the seventh postoperative day. The postoperative renal dysfunction (serum creatinine level >2.0 mg/dl) was 28.6% in group A and 50% in group B, while it was only 8.4% in group C, although no patient required either temporary or permanent hemodialysis. The postoperative peak BUN over 30 min suprarenal clamp was significantly higher than that within 30 min. In summary, the postoperative renal function was impaired after an extended bilateral suprarenal clamp. These findings suggest that if prolonged renal ischemia is thus expected, then renal preservation should be considered.

Aortic valve repair in dominant aortic regurgitation.

OBJECTIVE We studied immediate and mid-term results after aortic valve repair. METHODS Immediate and mid-term results were studied in 63 patients undergoing aortic valve repair, calculating survival and reoperation free rates. RESULTS Subjects were 49 men and 14 women aged 15 to 76 years (mean: 53 +/- 17 years). Mean preoperative aortic regurgitation grading of 1 to 4 was 3.2 +/- 0.7. Mean preoperative New York Heart Association functional class was 1.9 +/- 0.8. Two in-hospital deaths occurred. (3.2%) Mean aortic regurgitation grade at discharge was 1.3 +/- 0.8 (p < 0.0001; vs preoperative grade) and functional class was 1.1 +/- 0.2 (p < 0.0001; vs preoperative class),--significantly improved. Overall follow-up was 98.4%, and mean follow-up continued 41.4 +/- 22.1 months. Mean functional class at follow-up was 1.2 +/- 0.4 (n = 49), improved from preoperative class (p < 0.0001). Mean aortic regurgitation grading at follow-up was 1.8 +/- 0.8 (n = 41), improved from preoperative grading (p < 0.0001). Five-year survival was 95.1 +/- 2.8%. One-year reoperation freedom was 96.6 +/- 2.4% and 5-year 77.9 +/- 6.9%. CONCLUSIONS Survival after surgery was good, while reoperation was comparable to other reports but less satisfactory compared to reoperation freedom after aortic valve replacement. Based on reoperative findings, a change in indication was made. We believe technical refinements could improve postoperative results.

Primary aortoenteric fistula with a chronic isolated abdominal aortic dissection: Report of a case

A 47-year-old woman on long-term hemodialysis due to a chronic isolated abdominal aortic dissection was admitted to our department with severe abdominal pain. She had not suffered any hematemesis or melena. An emergency laparotomy revealed an abdominal aortic aneurysm with a diameter of 60mm, densely adhered to the ileum. An aortoenteric fistula manifesting as intramural rupture into the ileum was found after infrarenal abdominal aortic and bilateral common iliac cross-clamping. The fistula on the ileac side was nontransmural, but that on the aortic side communicated with the pseudolumen of the abdominal aorta, and contained mural thrombus. The infrarenal abdominal aorta and bilateral common iliac arteries were replaced with a collagensealed woven Dacron bifurcated graft. Histological examination of the ileum in this portion showed intramural bleeding and xanthomatous granulation with foam cell infiltration in the thickened subserosa. While it is difficult to diagnose nonpenetrating aortoenteric fistula preoperatively, such a fistula must be considered in a patient with severe abdominal pain, for whom previous abdominal aortic surgery has been performed or when an abdominal aneurysm is observed. To our knowledge, no other case of an aortoenteric fistula presenting as an intramural rupture into the ileum in an isolated abdominal aortic dissection has ever been reported.

THROMBOTIC OBSTRUCTION OF A REINFORCED RINGED EXPANDED POLYTETRAFLUOROETHYLENE GRAFT CAUSED BY FORMATION OF A PSEUDOANEURYSM AT A NONANASTOMOTIC SITE : REPORT OF A CASE

We report herein the case of a 72-year-old man in whom a nonanastomotic pseudoaneurysm arose from a reinforced ringed expanded polytetrafluoroethylene (EPTFE) graft (Gore-Tex, Flagstaff, AZ, USA) following an axillobifemoral bypass. The pseudoaneurysm developed 2 years after graft insertion and induced graft thrombosis. The development of the pseudoaneurysm can be attributed to the fact that his axillobifemoral bypass graft was so short it deformed the proximal anastomosis, and the graft was subcutaneously tunneled onto the major pectoral muscle. These technical errors placed the graft under too much tension in the longitudinal direction, which resulted in graft disruption and pseudoaneurysmal formation, followed by thrombosis of the axillary artery. Moreover, the possibility of direct trauma at the time of insertion cannot be substantiated. Although the very poor compliance and design of the externally supported ring could not tolerate stretch deformity in the Gore-Tex graft, only one other case of a nonanastomotic pseudoaneurysm has ever been reported.

Transaortic mitral valve repair combined with a modified Bentall procedure in a patient with Marfan's syndrome: report of a case.

We report a case of transaortic mitral valve repair combined with aortic root and arch replacement in a patient with Marfan’s syndrome. Preoperative computed tomography and echocardiography showed acute aortic dissection (DeBakey type 1), severe aortic regurgitation, annuloaortic ectasia, and mild mitral regurgitation (MR). We performed artificial chordae implantation to the anterior mitral leaflet (AML) through the aortic root, followed by insertion of an aortic composite graft and replacement of the aortic arch. The patient is well 55 months after the operation, with minimal MR. We think that the transaortic approach is a good alternative for exposure and correction of the AML and its apparatus in special circumstances.

THE RELEASE OF NITROGLYCERIN ABSORBED INTO THE CENTRAL VENOUS CATHETER

This study was conducted to evaluate the release of nitroglycerin (NG) that has been absorbed into the central venous catheter. A 0.05% NG solution was infused through a central venous catheter and the flow rates were set at 1, 5, or 10 ml/h, given over 12, 24, or 48 h. The catheter was flushed with lactate Ringer solution after completion of the NG infusion. The elution of the lactate Ringer solution from the tip of the catheter was then collected and assayed for its NG concentration by high performance liquid chromatography (HPLC). A higher concentration of NG was released with a faster flow rate and a longer infusion. The high level of NG release continued during the first 20 min, and ranged from a minimum of 0.07 mg/ml to a maximum that exceeded 0.15 mg/ml. Subsequently, the NG concentration gradually declined, but low concentrations of 0.006–0.02 mg/ml were still maintained 360 min later.Thus, it is suggested that if a catheter such as the Swan-Ganz continues to be used after the completion of a NG infusion, certain pharmacological effects due to the absorption of NG into the catheter body should be expected for at least 60 min.

Retroaortic Left Renal Vein Associated with Juxtarenal Aortic Abdominal Aneurysm Repair.

症例は53歳の男性. 狭心症の精査のさい juxtarenal type の腹部大動脈瘤を指摘された. 瘤径は7.2cmであったが3枝病変であったため冠動脈バイパス術を優先し, 2期的に腹部大動脈瘤に対しY型人工血管置換術を施行した. 術前のCTにて瘤の後面を走行する大動脈後性左腎静脈を認めたが術中損傷は認めず順調に経過した. 大動脈後性左腎静脈の発生頻度は2%程度であるが, 大動脈後面を腰静脈, 奇静脈または半奇静脈との吻合静脈が複雑に走行し, これらは非常に脆弱であるため腹部大動脈の不用意な剥離により予期せぬ大出血をきたす可能性があり, 死亡例も報告されている. このため的確な術前診断および慎重な術中操作が重要である. さらに本疾患は血尿などを主徴候とする大動脈左腎静脈瘻, 左腎静脈補捉症候群と関連することも念頭におく必要がある.

Cardiopulmonary bypass established via a sutured vascular graft in the presence of extraanatomic bypass

Cardiopulmonary bypass (CPB) was established via a sutured collagen sealed knitted Dacron graft in two patients who had undergone extraanatomic bypasses for lower limb ischemia, whose ascending aorta was not suitable for cannulation. One patient, with a history of femorofemoral bypass, underwent surgery for a ruptured aortic arch aneurysm (AAA) and the other patient, with a history of axillobifemoral bypass for chronic dissection involving the aortic arch and descending aorta, had unstable angina and underwent coronary artery bypass grafting. This technique of perfusion was found to be safe and effective for patients with an impaired ascending aorta who have undergone an extraanatomic bypass for the lower limb.

Preliminary Clinical Use of a New Bifurcated Graft for Peripheral Vascular Surgery

We describe herein a technique of performing a unilateral common ilio-bilateral femoropopliteal bypass using a small diameter bifurcated graft. The prosthesis, manufactured by Vascutek Ltd., is made of a gelatin-impregnated knitted Dacron graft with an externally ringed support. The diameter of the primary tube is 8 mm with a length of 25 cm, and the secondary tube has a diameter of 7 mm with a length of 75 cm. A total of six patients were operated on using this procedure, through an extraperitoneal approach. Postoperative angiographies showed excellent graft patency and Doppler ultrasound studies revealed a significant increase in the ankle-brachial pressure index in all patients. Using this newly designed small-diameter bifurcated graft, complete revascularization of multilevel occlusive disease can be performed with low operative mortality, and satisfactory relief of the ischemic symptoms can be achieved by the bilateral sequential proximal and distal bypasses.