Effects of extracorporeal membrane oxygenation pump flow, backflow cannulae, mean arterial blood pressure, and pulse pressure on Doppler-derived flow velocities of the lower limbs in patients on peripheral veno-arterial extracorporeal membrane oxygenation: A pilot study.

BACKGROUND: Reported rates of limb ischaemia on peripheral veno-arterial extracorporeal membrane oxygenation (pVA ECMO) vary from 1-52%. OBJECTIVES: Primary: To explore (i) the feasibility for appropriately trained intensive care unit staff to measure Doppler derived flow velocities of the lower limbs for patients on pVA ECMO; and (ii) whether these measurements are clinically useful. Secondary: explore the relationship between ECMO pump flow, backflow cannulae (BFC) properties, mean arterial blood pressure (MAP), and pulse pressure on flow velocities. METHOD: Inclusion criteria: age>18 years, on pVA ECMO >24 hours. EXCLUSION CRITERIA: any guardianship limitations and patients without a BFC. Serial patients receiving pVA-ECMO over a 10 month period had Doppler derived flow velocities of the lower limbs sampled. Simultaneously, other pertinent parameters were recorded. 80% inclusion was considered clinically feasible. Study personnel were asked for feedback regarding the ease and usefulness of studies. RESULTS: 15 of 17 patients were included: 88% inclusion. Mean peak systolic velocity (PSV) in the cannulated limb was 31 ± 29 cm/s in the dorsalis pedis (DP) and 27 ± 18 cm/s posterior tibial (PT). Similar flows were recorded in the non-cannulated limbs (DP 34 ± 29 cm/s, PT 44 ± 36 cm/s; P > 0.05). PSV was positively correlated with pulse pressure in cannulated and non-cannulated limbs respectively (r=0.63, P < 0.05; r=0.67 and P < 0.05). There was no significant correlation between PSV and MAP. ECMO pump flow and BFC were negatively correlated with PSV (r=-0.51, P < 0.05; r=-0.43, P < 0.05). CONCLUSION: It is generally feasible for ICU staff to measure flow velocities of the lower limbs for patients on pVA ECMO. It remains unclear how clinically useful these measurements are. Doppler derived flow velocities of arteries of the lower limbs of patients on pVA ECMO appear different to non-ECMO patients. PSV in the lower limbs of patients on pVA ECMO seems to be more related to pulse pressure than to other haemodynamic parameters.

Refractory ventricular fibrillations after surgical repair of atrial septal defects in a patient with CACNA1C gene mutation - case report.

BACKGROUND: Congenital long QT syndrome (LQTS) can cause ventricular arrhythmic events with syncope and sudden death resulting from malignant torsades de pointes (TdP) followed by ventricular fibrillations (VFs). However, the syndrome is often overlooked prior to the development of arrhythmic events in patients with congenital heart diseases demonstrating right bundle branch block on electrocardiogram (ECG). We present a case of an adult patient with congenital heart disease who developed VFs postoperatively, potentially due to his mutation in a LQTS related gene, which was not identified on preoperative assessment due to incomplete evaluation of his family history. CASE PRESENTATION: A 64-year-old man was diagnosed as having multiple atrial septal defects. He presented with no symptoms of heart failure. His preoperative ECG showed complete right bundle branch block (CRBBB) with a corrected QT interval time of 478 ms. He underwent open-heart surgery to close the defects through median sternotomy access. Three hours after the operation, he developed multiple events of TdP and VFs in the intensive care unit. Cardiopulmonary resuscitation and multiple cardioversions were attempted for his repetitive TdP and VFs. He eventually reverted to sinus rhythm, and intravenous beta-blocker was administered to maintain the sinus rhythm. After this event, his family history was reviewed, and it was confirmed that his daughter and grandson had a medical history of arrhythmia. A genetic test confirmed that he had a missense mutation in CACNA1C, p.K1580 T, which is the cause for type 8. CONCLUSIONS: This case highlights the importance of paying attention to other ECG findings in patients with CRBBB, which can mask prolonged QT intervals.

Proteomics-based analysis of lung injury-induced proteins in a mouse model of common bile duct ligation.

BACKGROUND: Lung injury is a life-threatening complication in patients with liver dysfunction. We recently provided an experimental lung injury model in mouse with common bile duct ligation. In this study, we aimed to characterize the pathologic and biochemical features of lung tissues in common bile duct ligation mice using a proteomic approach. METHODS: Common bile ducts of BALB/c mice, 8 weeks of age, were ligated operatively. CD31-expressing pulmonary cells were sorted with immunomagnetic microbeads, and protein profiles were examined by 2-dimensional gel electrophoresis. Based on the results of protein identification, immunohistochemistry and quantitative reverse transcription polymerase chain reaction were carried out in pulmonary and hepatic tissues. RESULTS: Two-dimensional gel electrophoresis revealed 3 major inflammation-associated proteins exhibiting considerable increases in the number of CD31-positive pulmonary cells after common bile duct ligation. Mass spectrometry analysis identified these proteins as SerpinB1a (48 kDa), ANXA1 (46 kDa), and S100A9 (16 kDa). Furthermore, the 3 proteins were more highly expressed in dilated pulmonary blood vessels of common bile duct ligation mice, in which neutrophils and monocytes were prominent, as shown by immunohistochemistry. More importantly, SerpinB1a mRNA and protein were significantly upregulated in the liver, whereas S100A9 and ANXA1 mRNA and protein were upregulated in the lungs, as shown by quantitative reverse transcription polymerase chain reaction and Western blotting. CONCLUSION: We identified 3 proteins that were highly expressed in the lung after common bile duct ligation using a proteomics-based approach.

Long-term outcome after mitral valve replacement with preservation of continuity between the mitral annulus and the papillary muscle in patients with mitral stenosis.

BACKGROUND AND AIM OF THE STUDY: The effect on left ventricular performance of mitral valve replacement (MVR) with preservation of continuity between the mitral annulus and papillary muscle was studied in patients with mitral stenosis (MS). METHODS: Forty patients with MS who underwent MVR between 1986 and 1995 and had long-term echocardiographic follow up were studied retrospectively. Eighteen patients had conventional MVR (CMVR group), and 22 (PMVR group) had either preservation of autologous chordae tendineae (n = 6) or replacement of the chordae with expanded polytetrafluoroethylene sutures (n = 16). RESULTS: Preoperatively, there were no significant differences between the two groups in age, body surface area, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), fractional shortening (FS) or ejection fraction (EF). At 3.1-6.5 years after surgery, periodic echocardiography showed significant differences (p <0.05) in LVESD (35.8 versus 31.6 mm, respectively, in the CMVR and PMVR groups) and FS (31.8% versus 38.1%). At 6.6-9.7 years postoperatively, no significant differences were observed between the two groups in FS, but LVESD was significantly greater in the CMVR group than in the PMVR group (37.3 versus 31.5 mm). CONCLUSION: In the long term, MVR with preservation of continuity between the mitral annulus and papillary muscle improves systolic left ventricular performance in patients with MS.

Acute type B aortic dissection complicated with a mycotic aortic arch aneurysm.

A successfully-treated case of acute type B aortic dissection associated with a mycotic aneurysm is reported. A 69-year-old man had a history of febrile illness and a high CRP level with increased enzyme activity of the hepatobiliary system before the onset. The culture of the abscess in the distal arch aneurysm revealed Bacteroides fragilis. A Dacron graft replacement between the distal arch and the proximal descending aorta was successfully performed with Teflon felt reinforcement, and the graft was covered with omental flap. The patient was discharged without recurrence of infection 2 months after the graft replacement.

Aortic aneurysm and aortic regurgitation following aortic valve replacement due to Takayasu's arteritis.

A 26-year-old man who underwent aortic valve replacement for aortic regurgitation due to Takayasu's arteritis 2 years earlier experienced left amaurosis persisting for some minutes. Computed tomography showed aneurysmal dilation of the ascending aorta to a diameter of 60 mm and occlusion of the left carotid artery. Cardiac echography showed perivalvular leakage. Following administration of a calcium antagonist, the patient's amaurosis subsided and brain bloodstream scintigraphy showed no abnormalities. We resected the aneurysm instead of using Bentall's operation. Following an uncomplicated postoperative course, the patient was discharged 21 days after surgery and echocardiography has shown no perivalvular leakage to date.

Clinical significance of anastomotic leak in ascending aortic replacement for acute aortic dissection.

'Anastomotic leak' after ascending aortic replacement for acute aortic dissection, which is determined as direct forward blood flow into the false lumen at the distal anastomosis, prevents the false lumen from being thrombosed. The aim of this study is to determine whether the leak influences on residual aortic growth. Between October 1999 and May 2006, 100 patients presenting for acute type A aortic dissection underwent surgery at our institution. Among the population, 34 patients who underwent ascending aortic replacement and have been followed by computed tomography (CT) for over 6 months were reviewed. On the follow-up CT, maximum diameter of aortic arch and descending aorta were measured and the presence of anastomotic leak was determined. The growth rates of aortic arch and descending aorta in patients diagnosed as having anastomotic leak were greater than patients not having leak (P=0.003, P<0.001, respectively). Initial maximum diameter just after ascending aortic replacement was greater in patients with anastomotic leak than without anastomotic leak in aortic arch and descending aorta (P=0.013, P=0.06). Anastomotic leak after ascending aortic replacement for acute type A aortic dissection contributed to remnant aortic growth. More sophisticated method for reapproximation of dissected aorta should be dictated.

Abdominal aortic aneurysm associated with horseshoe kidney.

The optimal approach to abdominal aortic aneurysm with horseshoe kidney is still debated. We describe a successful abdominal aortic aneurysm repair through a left retroperitoneal approach in a 77-year-old woman with a horseshoe kidney.

Congenital quadricuspid aortic valve associated with severe regurgitation.

A 56-year-old man was referred because of severe aortic regurgitation. He had a quadricuspid aortic valve with a small accessory cusp between the right coronary and noncoronary cusps. The ostium of the right coronary artery was deviated toward the accessory cusp commissure. Aortic valve replacement was performed with a bioprosthesis. The resected cusps showed fibrotic thickening with calcification and fenestration.

Aortic root replacement for destructive aortic valve endocarditis with left ventricular-aortic discontinuity.

BACKGROUND: Destructive aortic valve endocarditis causes the development of left ventricular-aortic discontinuity. Our experience of aortic root replacement in patients with the left ventricular-aortic discontinuity is presented. METHODS: Between 1999 and 2006, 8 patients (7 men, 1 woman) with left ventricular-aortic discontinuity underwent aortic root replacement in our institute. Their mean age was 56 years. Six patients were in New York Heart Association functional class III or higher. Four patients were diagnosed to have native valve endocarditis, and 4 had prosthetic valve endocarditis (previous aortic valve replacements in 2 patients, aortic root replacements in 2). Radical débridement of the aortic root abscess was performed in all patients, followed by reconstruction of the aortic annulus using autologous or xenogenic pericardium in 2 patients. Fibrin glue saturated with antibiotics was applied into the cavity in 5 patients. Aortic root replacement was achieved with pulmonary autograft (Ross procedure) in 4 patients and stentless aortic root xenograft in 3. One patient who had advanced liver cirrhosis underwent aortic valve replacement with a stentless xenograft by subcoronary fashion. RESULTS: No patients died during hospitalization or follow-up. Freedom from major adverse cardiac events was noted in 67% of the patients at 5 years. CONCLUSIONS: An excellent outcome can be achieved by radical exclusion of abscess in the cavity, followed by root replacement with viable pulmonary autograft or flexible stentless aortic root xenograft in patients with left ventricular-aortic discontinuity.

Influence of perioperative hemodynamics on spinal cord ischemia in thoracoabdominal aortic repair.

BACKGROUND: The purpose of this study is to investigate the influence of perioperative circulation on spinal cord during the repair of descending thoracic or thoracoabdominal aortic aneurysms. METHODS: From October 1999, 92 patients (aged 66 +/- 13 years; 65 men) underwent the repair of descending thoracic (n = 30) or thoracoabdominal aortic aneurysm (Crawford I, 9; II, 14; III, 35; IV, 4). We measured the time duration of hypotension, defined as follows, and evaluated the relationship between the incidence of paraplegia and each duration: T1, systolic arterial pressure less than 80 mm Hg, or mean pressure less than 60 mm Hg during aortic cross-clamping; T2, distal aortic pressure less than 60 mm Hg during aortic cross-clamping; T3, systolic arterial pressure less than 80 mm Hg after coming off bypass; T4, systolic arterial pressure less than 80 mm Hg in the intensive care unit. RESULTS: Hospital mortality was 8% (7 patients). Neurologic deficits occurred in 10 patients (10.9%). The T1 and T2 periods showed no difference between paraplegia cases (group P) and normal cases (group N). The T3 periods in both groups were 54 +/- 52 and 6.6 +/- 18, and the T4 periods were 62 +/- 89 and 2.3 +/- 14, respectively. The T3 and T4 periods in group P were significantly longer than in group N (p < 0.0001). Multivariate analysis demonstrated that T3 was an independent risk factor for paraplegia. When divided according to body temperature, the T2 period under mild hypothermia was significantly longer in group P than in group N, as well as the T3 and T4 periods. CONCLUSIONS: Perioperative hemodynamics stability is of vital importance for spinal cord protection during thoracoabdominal aortic surgery. In particular, the duration of hypotension after coming off bypass was an independent risk factor for paraplegia.

Comparison of distensibility of the aortic root and cusp motion after aortic root replacement with two reimplantation techniques: Valsalva graft versus tube graft.

The aim of this study is to evaluate distensibility of the aortic root and function of the aortic cusp after aortic root replacement using valve sparing procedure. Between October 1999 and August 2006, valve sparing aortic root replacements were performed in 39 patients who had annuloaortic ectasia (AAE) and aortic valve regurgitation. Reimplantation type of valve-sparing procedure was performed with a tube graft (n=12) or a Valsalva graft (n=27). Echocardiographic studies were performed six months after the operation comparing Valsalva graft (Group V, n=15), tube graft (Group T, n=5), and normal control (Group C, n=5). Percent changes in radius (PCR) of the aortic root were measured as indices of distensibility. Rapid valve opening velocity (RVOV/HR (mm/s/min)) and rapid valve closing velocity (RVCV/HR (mm/s/min)) of the aortic cusp were analyzed in each group. Root distensibility of sinus in Group T (1.9+/-1.1) was significantly smaller than Group C (7.2+/-1.8) (P=0.003). RVOV/HR in Group T was highest among the three groups (T: 48.2+/-6.2, V: 36.2+/-11.9, C: 33.7+/-9.6). RVCV/HR showed no difference among the three groups (T: 26.1+/-6.7, V: 40.7+/-16.6, C: 28.4+/-16.3). In conclusion, sinus distensibility of the Valsalva graft was well preserved and valve-opening characteristics with the Valsalva graft were identical to normal.

Total arch replacement for aneurysm of the aortic arch: factors influencing the distal anastomosis.

Total arch replacement (TAR) for aneurysm of the aortic arch through the midsternotomy has several advantages over left thoracotomy. The purpose of this study was to identify the factors that might have an effect on the distal anastomosis through midsternotomy. From October 1999 to August 2005, 125 patients underwent TAR for aneurysm of the aortic arch through midsternotomy. Ninety-four patients with antegrade cerebral perfusion were selected. Distal anastomosis was performed under circulatory arrest (CA) of the lower body. Preoperatively, the diameter of aneurysm, the depth of distal end of aneurysm from anterior skin surface and the anteroposterior diameter of body trunk were measured. Postoperatively, the distance from the carina to the distal anastomosis was measured. There were six early deaths (6.4%). Duration of CA was 37+/-7.6 min. Diameter of the aneurysm was 60.6+/-13.2 mm and the depth of the distal end of aneurysm was 139+/-20.6 mm. There was no correlation between CA time and these factors. The anteroposterior diameter of body trunk was 200+/-18.0 mm and has a correlation with CA time. The depth of distal end of aneurysm from anterior skin surface was the only factor that affected duration for distal anastomosis.

The adverse effect of back-bleeding from lumbar arteries on spinal cord pathophysiology in a rabbit model.

OBJECTIVE: The purpose of this study was to evaluate the adverse effect of back-bleeding from the lumbar arteries on spinal cord pathophysiology in a rabbit model. METHODS: White rabbits were divided into 3 groups. Through laparotomy, the abdominal aorta was clamped below the renal artery and above the aortic bifurcation for 15 minutes. In group 1 (n = 13), back-bleeding from the lumbar arteries was drained from the aorta during aortic clamping. In group 2 (n = 10), back-bleeding was not drained. Group 3 (n = 6) was the sham-operated group. Postoperative hind limb function was evaluated using the modified Tarlov scale, and cell damage was analyzed by counting the number of intact motor neurons and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive neurons. RESULTS: At 4 hours after operation, all animals were neurologically impaired in group 1 and normal in group 2. Motor neurons were significantly damaged in group 1 compared with groups 2 and 3 (P < .05). Forty-eight hours later, almost all animals were neurologically and pathologically damaged in groups 1 and 2. There was no difference in the number of normal motor neurons between the two groups, but the number of TUNEL-positive cells in group 2 was significantly larger than those in group 1. CONCLUSIONS: Rabbits with 15-minute aortic clamping in the infrarenal portion showed delayed paraplegia, and those with back-bleeding from lumbar arteries showed early onset of paraplegia. The prevention of back-bleeding from intercostal arteries and lumbar arteries during thoracoabdominal aortic surgery was considered to reduce spinal ischemic injury.

Usefulness of transcranial motor evoked potentials during thoracoabdominal aortic surgery.

BACKGROUND: The purpose of this study was to evaluate the efficacy of myogenic transcranial motor evoked potentials (tc-MEPs) for spinal cord ischemia in the repair of descending thoracic or thoracoabdominal aortic aneurysms. METHODS: Intraoperative tc-MEPs was used in 72 patients who underwent the repair of descending thoracic (n = 24) or thoracoabdominal aortic aneurysms (n = 49) classed as Crawford I in 10 patients, II in 12, III in 23, and IV in 3. There were 52 men and 20 women, and their mean age was 64.9 +/- 12.8 years. Tc-MEPs were recorded by transcranial electrical stimulation and compound muscle action potentials. RESULTS: The hospital mortality rate was 5.6% (n = 4), and the incidence of neurologic deficits was 11.1% (n = 8). All patients whose MEP amplitude recovered to more than 75% of the baseline showed normal spinal function, and 8 of 9 patients whose MEP amplitude decreased to below 75% of the baseline at the end of the procedure showed neurologic deficits postoperatively. The sensitivity of tc-MEPs was 100% and specificity was 98.4%. Latency in patients with postoperative paraplegia was 123% +/- 9% and was significantly prolonged at the end of the procedure. CONCLUSIONS: Tc-MEPs were very sensitive and specific to spinal cord ischemia with reduced amplitude and prolongation of the latency period. Tc-MEPs are considered a useful monitor of spinal cord ischemia during descending thoracic or thoracoabdominal aortic surgery.

Three cases of newly developed paraplegia after repairing type A acute aortic dissection.

Postoperative paraplegia after repairing type A acute aortic dissection has been rarely reported and the causes have not been clearly elucidated. We had three cases of newly developed paraplegia after repair of type A acute aortic dissection. In these cases, we speculated that some intercostal arteries were occluded by completely thrombosed false lumen with late onset of systemic hypotension, which might have reduced spinal cord perfusion followed by paraplegia.

Reconstruction of the intercostal arteries with small-branched grafts in patients with thoracoabdominal or descending aortic aneurysms.

An extent II thoracoabdominal aortic aneurysm of 60 mm diameter was exposed through the left 6(th) intercostal space and retroperitoneal approach. The partial cardiopulmonary bypass was initiated through the femoral arterial and venous cannulation. A knitted Dacron graft of 22 mm with four spatially orientated branches for the abdominal viscera and five branches for the intercostal arteries was utilized. The thoracoabdominal aorta was replaced with staged segmental aortic clamping. The proximal aorta, just distal to the left subclavian artery, was completely transected and anastomosed to the graft. The descending aorta was clamped at Th 10 level. The Th 8 and 9 intercostal arteries were clamped from the outside of the aorta. After opening the aorta, the left orifice of Th 8(th) and Th 9(th) intercostal arteries were anastomosed to the side branches of the graft, respectively. Similarly, the 10(th) and 11(th) intercostal arteries were reconstructed. After clamping the infra-renal portion of the abdominal aorta, four visceral arteries were perfused using an 8 French size balloon-tipped catheter. Each artery was anastomosed to the side branch of the graft. The distal anastomosis was performed and cardiopulmonary bypass was weaned-off.

Disruption of the vascular prosthesis caused by aortic calcification after replacement of the thoracoabdominal aortic aneurysm.

A 52-year-old man underwent a replacement of the thoracoabdominal aorta. The aorta was severely calcified, and was replaced by a 24-mm woven Dacron (Vascutek, Renfrewshire, Scotland) graft wrapped with the calcificated aneurysmal wall. His postoperative course was uneventful; however, he collapsed on the 18th postoperative day. He underwent an emergent thoracotomy and the wrapped aneurysmal wall was taken down. The prosthesis graft had a 1-mm disruption in the middle portion, which did not relate to the anastomoses. Experimental study ex vivo showed that disruption of the prosthesis could have occurred after a 3-week pulsatile force caused by a seashell simulating aortic calcification.

Surgical results of acute aortic dissection complicated with cerebral malperfusion.

BACKGROUND: In patients with acute type A aortic dissection complicated by cerebral malperfusion, the surgical treatment remains challenging. This retrospective study reports the results of surgical interventions and the clinical features of these patients. METHODS: From 1999 to 2004, 63 patients underwent surgical treatment for acute type A aortic dissection. Sixteen patients (25.3%) showed preoperative newly developed neurologic deficits (cerebral malperfusion). In patients with cerebral malperfusion, the characteristics, neurologic symptoms, computed tomography findings, interval from onset to operation, and operative details (procedure, arterial cannulation site, method of brain protection) were reviewed. RESULTS: The hospital mortality rate was 43.7% (7 of 16 patients) for the cerebral malperfusion group and 17.0% (8 of 47 patients) for the noncerebral malperfusion group (all patients, 23.8%). Multivariate analysis showed preoperative cerebral malperfusion as the sole risk factor for hospital mortality. Six patients, including all patients in a preoperative coma, died of severe brain damage within 1 month after surgery. Most patients were diagnosed with right hemispheric cerebral infarction by postoperative brain computed tomography. The operative details and the time interval from onset to operation were not significant predictors of death. The cumulative survival rate at 4 years was 75.5% in patients without cerebral malperfusion and 50.1% with cerebral malperfusion (p = 0.091). CONCLUSIONS: The results of surgical treatment for acute type A dissection complicated with cerebral malperfusion demonstrated high hospital mortality, but the long-term survival was similar to patients without cerebral malperfusion, with an acceptable neurologic outcome, excluding preoperative coma patients. Appropriate protection of ischemic brain tissue should be implemented to improve the surgical results in these patients.

Transcranial myogenic motor-evoked potentials after transient spinal cord ischemia predicts neurologic outcome in rabbits.

OBJECTIVE: Myogenic transcranial motor-evoked potentials (tc-MEPs) were applied to monitor spinal cord ischemia in the repairs of thoracoabdominal aortic aneurysms. We investigated whether tc-MEPs after spinal cord ischemia/reperfusion could be used to predict neurologic outcome in leporine model. METHODS: Tc-MEPs were measured at 30-second intervals before, during, and after spinal cord ischemia (SCI) induced by balloon occlusion of the infrarenal aorta. Twenty rabbits were divided into five groups. Four groups (n = 4 animals in each group) had transient ischemia induced for 10, 15, 20, or 30 minutes. In fifth group, the terminal aorta at the aortic bifurcation was occluded for 30 minutes. All animals were evaluated neurologically 48 hours later, and their spinal cords were removed for histologic examination. RESULTS: The tc-MEPs in each SCI group rapidly disappeared after SCI. After reperfusion, the recovery of tc-MEPs amplitude was inversely correlated to duration of SCI. Tc-MEPs amplitude at one hour after reperfusion was correlated with both neurologic score and number of neuron cells in the spinal cord 48 hours later. Logistic regression analysis demonstrated that the neurologic deficits differed significantly between animals with tc-MEPs amplitude of less than 75% of the baseline and those with an amplitude of more than 75%. CONCLUSIONS: The amplitude of tc-MEPs after ischemia /reperfusion of the spinal cord showed a high correlation with durations of SCI, with neurologic deficits, and with pathologic findings of the spinal cord. Tc-MEPs, therefore, could be used to predict neurologic outcome. In particular, tc-MEPs whose amplitude recovered by less than 75% indicated a risk of paraplegia.