Katsuhito Ueno

Open stent-grafting for aortic arch aneurysm is associated with increased risk of paraplegia

BACKGROUND Open surgery using the endovascular stent-graft is a novel technique that lessens the invasiveness of surgery for the aortic arch. However, the outcome of this procedure remains uncertain. METHODS Between November 1996 and July 2000, a total of 19 patients underwent open surgery using an endovascular stent-graft for thoracic aortic aneurysms. There were 15 men (78.9%) and 4 women (21.1%). Patient age ranged from 29 to 82 years (mean 69.3 years, median 74 years). Atherosclerotic thoracic aortic aneurysms were present in 17 patients (89.4%) and aortic dissection in 2 patients (10.5%). RESULTS Two patients (10.5%) died in the hospital and 4 patients (21.1%) presented with paraplegia postoperatively. Among the 4 patients with postoperative paraplegia, 1 case was complicated with intraoperative aortic dissection. The other 3 patients with paraplegia had spinal cord ischemic time of more than 60 minutes and intraoperative body weight gain of more than 4 kg. Of these 3 patients, hemodynamic instability after cardiopulmonary bypass was observed in 1 patient and cholesterin embolus in the anterior spinal artery was found at autopsy in another. On univariate analysis, age greater than 75 years was the only risk factor associated with paraplegia (p < 0.05). Autopsy findings for the 2 patients showed that the Adamkiewicz arteries were not blocked by the stent-graft in either patient. CONCLUSIONS Intraoperative aortic dissection, embolization of the intercostal arteries, long ischemic time of the spinal cord, and excessive weight gain during operation may have been associated with the high incidence of paraplegia after open surgery using the endovascular stent-graft.

Outcome and survival analysis of pulmonary metastasectomy for hepatocellular carcinoma

OBJECTIVE The lung is the most common site for extrahepatic metastasis from hepatocellular carcinoma (HCC). We previously reported in a series of 20 patients that pulmonary metastasectomy for HCC is feasible in selected patients. The objective of this study was to re-evaluate the long-term outcomes and prognostic factors with an additional 25 patients. METHODS We retrospectively analyzed the records of 45 consecutive patients who underwent pulmonary metastasectomy due to HCC at our institution between 1990 and 2010. RESULTS Thirty-nine patients underwent hepatectomy or liver transplantation, whereas six patients underwent locoregional therapy for primary liver lesions. Twenty-seven patients died during a median 17.6-month follow-up period. The 2-year disease-free survival (DFS) was 19.5%. The 5-year overall survival (OS) was 40.9%. History of recurrence and serum des-gamma-carboxy prothrombin (DCP) level >40 mAU ml(-1) at initial pulmonary resection were unfavorably associated with OS in univariate analysis. CONCLUSIONS Pulmonary metastasectomy for HCC in selected patients resulted in relatively good outcomes with regard to OS. History of recurrence and serum DCP levels were shown to be candidates of prognostic factors for OS.

Minimal damage during endoscopic latissimus dorsi muscle mobilization with the harmonic scalpel

BACKGROUND To reduce wound-related complications, a video-assisted surgical technique has been adopted for the mobilization of the latissimus dorsi muscle. We postulated that thermal damage to the muscle might be minimized by using a Harmonic Scalpel instead of electrocautery during this procedure. METHODS Canine latissimus dorsi muscles were mobilized through a small incision, assisted by a videoscope. In 6 dogs, dissection with electrocautery was used to mobilize the latissimus dorsi muscle. In 6 other dogs, the Harmonic Scalpel was used. We compared operation times, wound infection rates, histologic changes in the muscles, and ease of handling between these groups. RESULTS The operation time was significantly shorter in the Harmonic Scalpel group than in the electrocautery group (61.5 versus 106.5 minutes, p = 0.00014). The Harmonic Scalpel caused less histologic damage to the mobilized muscles and produced less vision-obscuring smoke. CONCLUSIONS The Harmonic Scalpel shortens the operation, minimizes muscle damage, and facilitates the performance of video-assisted latissimus dorsi muscle mobilization.

Arterial blood gas management in retrograde cerebral perfusion: the importance of carbon dioxide

OBJECTIVES Many interventional physiological assessments for retrograde cerebral perfusion (RCP) have been explored. However, the appropriate arterial gas management of carbon dioxide (CO2) remains controversial. The aim of this study is to determine whether alpha-stat or pH-stat could be used for effective brain protection under RCP in terms of cortical cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), and distribution of regional cerebral blood flow. METHODS Fifteen anesthetized dogs (25.1+/-1.1 kg) on cardiopulmonary bypass (CPB) were cooled to 18 degrees C under alpha-stat management and had RCP for 90 min under: (1), alpha-stat; (2), pH-stat; or (3), deep hypothermic (18 degrees C) antegrade CPB (antegrade). RCP flow was regulated for a sagittal sinus pressure of around 25 mmHg. CBF was monitored by a laser tissue flowmeter. Serial analyses of blood gas were made. The regional cerebral blood flow was measured with colored microspheres before discontinuation of RCP. CBF and CMRO2 were evaluated as the percentage of the baseline level (%CBF, %CMRO2). RESULTS The oxygen content of arterial inflow and oxygen extraction was not significantly different between the RCP groups. The %CBF and %CMRO2 were significantly higher for pH-stat RCP than for alpha-stat RCP. The regional cerebral blood flow, measured with colored microspheres, tended to be higher for pH-stat RCP than for alpha-stat RCP, at every site in the brain. Irrespective of CO2 management, regional differences were not significant among any site in the brain. CONCLUSIONS CO2 management is crucial for brain protection under deep hypothermic RCP. This study revealed that pH-stat was considered to be better than alpha-stat in terms of CBF and oxygen metabolism in the brain. The regional blood flow distribution was considered to be unchanged irrespective of CO2 management.

Hypertrophic obstructive cardiomyopathy associated with mitral regurgitation due to infective endocarditis.

A 25-year-old woman treated for hypertrophic obstructive cardiomyopathy and suffering from mitral regurgitation due to infective endocarditis was referred to our department for surgery. Preoperative examinations revealed asymmetric septal hypertrophy, a large left ventricular outflow gradient (100 mmHg), and perforation of the anterior mitral leaflet resulting in severe mitral regurgitation. The entire mitral complex was resected and septal myectomy conducted to dilate the left ventricle. A bioprosthetic valve was then implanted. Although postoperative heart failure was severe, cardiac function has gradually recovered. The left ventricular outflow gradient has decreased to 8 mmHg, the diastolic left ventricular diameter has increased from 26 to 30 mm, and her New York Heart Association classification has improved from IV to I.

Doppler ultrasonographic identification of the critical segmental artery for spinal cord protection

OBJECTIVE The purpose of this study is to evaluate the possibility of identifying critical segmental arteries (CSAs) based on Doppler ultrasonographic hemodynamics. METHODS In 18 mongrel dogs, the descending aorta was scanned directly with a 5-MHz linear probe through left thoracotomies and the flow velocities in segmental arteries were measured by pulsed Doppler. The aorta was cross-clamped between Th13 and L1, and flow velocity changes were recorded. According to flow increases, segmental arteries were divided into three groups: arteries with the largest flow increase (L-arteries), arteries with the smallest increase (S-arteries) and other arteries (O-arteries). Animals were divided into three groups. One aortic segment including an L-artery or an S-artery was perfused via a temporary shunt during 30-min aortic cross-clamping distal to the left subclavian artery (Group L or Group S) and neurological outcomes were compared with those of animals without shunting (Group N) after 24 and 48 h. RESULTS L-arteries had significantly larger flow increases than S- and O-arteries (74.3+/-33.8, 20.4+/-9.8 and 33.3+/-17.8 cm/s, P<0.01). In Group N, five of the six animals were completely paraplegic (Tarlov Grade 0) and the other was Grade 1. In Group S, four animals were Grade 4 and two were Grade 0 after 24h. However, two animals showed delayed paraplegia. Therefore, four animals were Grade 0 and two were Grade 4 after 48 h. All animals in Group L were neurologically normal (Grade 4) at both after 24h (vs. Group N, P=0.0013) and 48 h (vs. Group N, P=0.0013; vs. Group S, P=0.019). CONCLUSIONS Flow responses to aortic cross-clamping differed among segmental arteries and selective perfusion of L-arteries completely prevented paraplegia. Therefore, L-arteries were considered to be CSAs. Hemodynamic measurement of segmental arterial flow using Doppler ultrasonography could be clinically useful for spinal cord protection during thoracoabdominal aortic surgery.

Cerebral Metabolism of Nitric Oxide during Retrograde Cerebral Perfusion

The aim of this study was to determine whether alpha- or pH-stat protects the brain during deep hypothermic retrograde cerebral perfusion. Fifteen anesthetized dogs on cardiopulmonary bypass were cooled to 18°C under alpha-stat and underwent retrograde cerebral perfusion for 90 minutes under alpha-stat or pH-stat, or underwent antegrade cardiopulmonary bypass under alpha-stat as the control. Cerebral blood flow of the cortex was monitored and serial analyses of blood gases and total nitric oxide oxidation products made. Cerebral blood flow and cerebral metabolic rate for oxygen were significantly higher and plasma levels of nitric oxide oxidation products in the outflow from the brain were significantly lower in retrograde cerebral perfusion under pH-stat than under alpha-stat. This study shows that reduced levels of nitric oxide oxidation products may protect against neuronal damage induced by nitric oxide and that increased cerebral blood flow under pH-stat may lead to a reduction of nitric oxide oxidation products. Under retrograde cerebral perfusion, pH-stat is thus better than alpha-stat for protecting the brain.

Cavernous hemangioma arising from the diaphragm.

A 51-year-old man was referred to our hospital with an abnormal nodule in the right lung field. Computed tomography revealed a homogeneous nodule adjacent to the diaphragm, which appeared to be an extrapulmonary lesion. No hilar or mediastinal lymph node swelling was detected, and positron-emission tomography showed no significant uptake. At surgery, 2 red papillary tumors were found, originating from the right diaphragm, and tumor extirpation was performed. The pathological diagnosis was cavernous hemangioma.