Pediatric physiologic pulsatile pump enhances cerebral and renal blood flow during and after cardiopulmonary bypass

Controversy over benefits of pulsatile flow after pediatric cardiopulmonary bypass (CPB) continues. Our study objectives were to first, quantify pressure and flow waveforms in terms of hemodynamic energy, using the energy equivalent (EEP) formula, for direct comparisons, and second, investigate effects of pulsatile versus nonpulsatile flow on cerebral and renal blood flow, and cerebral vascular resistance during and after CPB with deep hypothermic circulatory arrest (DHCA) in a neonatal piglet model. Fourteen piglets underwent perfusion with either an hydraulically driven dual-chamber physiologic pulsatile pump (P, n = 7) or a conventional nonpulsatile roller pump (NP, n = 7). The radiolabeled microsphere technique was used to determine the cerebral and renal blood flow. P produced higher hemodynamic energy (from mean arterial pressure to EEP) compared to NP during normothermic CPB (13 +/- 3% versus 1 +/- 1%, p < 0.0001), hypothermic CPB (15 +/- 4% versus 1 +/- 1%, p < 0.0001) and after rewarming (16 +/- 5% versus 1 +/- 1%, p < 0.0001). Global cerebral blood flow was higher for P compared to NP during CPB (104 +/- 12 ml/100g/min versus 70 +/- 8 ml/100g/min, p < 0.05). In the right and left hemispheres, cerebellum, basal ganglia, and brainstem, blood flow resembled the global cerebral blood flow. Cerebral vascular resistance was lower (p < 0.007) and renal blood flow was improved fourfold (p < 0.05) for P versus NP, after CPB. Pulsatile flow generates higher hemodynamic energy, enhancing cerebral and renal blood flow during and after CPB with DHCA in this model.     

Risk factors for distal stent graft-induced new entry tear after endovascular repair of thoracic aortic dissection

ObjectiveA review of the literature was conducted for incidence, outcomes, and risk factors for distal stent graft-induced new entry (SINE) after thoracic endovascular aortic repair (TEVAR) of aortic dissection.MethodsThe review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.ResultsSeven articles reporting on 1415 patients with thoracic aortic dissection undergoing TEVAR without supplemental distal bare stenting were included. In this cohort, 86 patients were treated for a residual type A aortic dissection and 1329 for a complicated type B aortic dissection. Distal SINE occurred in 112 patients (7.9%). The mean time to identification of distal SINE was 19 ± 7 months. The incidence of distal SINE after TEVAR for type B aortic dissection differed on the basis of whether it was a chronic or acute dissection repair and was, respectively, 12.9% (43/331) and 4.3% (12/273). Successful secondary interventions were performed in 54% of the patients. All the studies analyzing the relationship between distal stent graft oversizing and incidence of distal SINE reported a significantly higher rate of SINE with oversizing.ConclusionsThe successful management of complicated descending thoracic aortic dissections by TEVAR is well established. Whereas distal SINE is relatively frequent, if it does occur, the complication can generally be treated with additional TEVAR without a poor outcome. The main determinant of SINE seems to be excessive distal oversizing.     

Persistence of collateral circulation after correction of aortic coarctation

The persistence of collateral circulation was evaluated one year after the correction of experimental aortic coarctation (CoA) by assessing renal perfusion with the Xenon 133-washout method and measuring distal aortic blood pressure during cross-clamping of the thoracic aorta. CoA was created in 7 puppies at 2 months of age and was corrected after a follow-up with a venous patch when the dogs were 9 months old. Two of the dogs were lost during the corrective operation due to anaesthetic complications. Four sham-operated dogs served as controls. One year after correction of CoA, four of the dogs had a pressure gradient of less than 5 mmHg at the site of CoA and one a pressure gradient of 15 mmHg. In renal perfusion measurements a mean decrease of 49% and 96% was found in the study and control groups, respectively. Blood pressures in the distal aorta decreased 47% and 83%, respectively. Two dogs in the study group had a distal blood pressure under 50 mmHg and their renal perfusion decreased markedly. Collateral circulation decreased with time after a good anatomic correction of CoA, so that one year after correction of experimental CoA about one half of the initial collateral capacity remained. This suggests that in most reoperations performed at least one year after the primary corrections, temporal shunting or a left side bypass is necessary to ensure sufficient circulation in the distal organs.     

Novel cerebral physiologic monitoring to guide low-flow cerebral perfusion during neonatal aortic arch reconstruction

OBJECTIVE: This study was undertaken to describe the combined measurement of cerebral blood flow velocity and cerebral oxygen saturation as a guide to bypass flow rate for regional low-flow perfusion during neonatal aortic arch reconstruction. METHODS: Data were prospectively collected from 34 patients undergoing neonatal aortic arch reconstruction with regional low-flow perfusion. Cerebral oxygen saturation and blood flow velocity were measured by near-infrared spectroscopy and transcranial Doppler ultrasonography, respectively, throughout cardiopulmonary bypass. After cooling to 17 degrees C to 22 degrees C, baseline values of cerebral oxygen saturation and blood flow velocity were recorded during full-flow bypass. Regional low-flow perfusion was instituted for aortic arch reconstruction, and bypass flow rate was adjusted to maintain cerebral oxygen saturations and blood flow velocities within 10% of baseline recorded during cold full-flow bypass. Cerebral oxygen saturations and blood flow velocities were recorded again after repair during full-flow hypothermic bypass. Bypass flow during regional low-flow perfusion was recorded, as were arterial pressure and blood gas data. One-way repeated measures analysis of variance was used to determine differences in values during regional low-flow perfusion relative to baseline and after perfusion. RESULTS: A mean bypass flow of 63 mL/(kg x min) was required to maintain cerebral oxygen saturations and blood flow velocities within 10% of baseline. Mean arterial pressure had a poor correlation with the required bypass flow rate (r(2) = 0.006 by linear regression analysis). Fourteen of 34 patients had a cerebral oxygen saturation of 95% during regional low-flow perfusion, placing them at risk for cerebral hyperperfusion if the cerebral oxygen saturation had been used alone to guide bypass flow. Pressure was detected in the umbilical or femoral artery catheter (mean 12 mm Hg) in all patients during regional low-flow perfusion. CONCLUSIONS: Cerebral blood flow velocity, as determined by transcranial Doppler ultrasonography, adds valuable information to cerebral oxygen saturation data in guiding bypass flow during regional low-flow perfusion. Its most important use may be prevention of cerebral hyperperfusion during periods with high near-infrared spectroscopic saturation values.     

Renal and splanchnic circulation during infrarenal aortic cross-clamping

The effect of infrarenal cross-clamping of the aorta on regional splanchnic and renal circulations was studied in seven dogs. Regional blood flow was determined with differentially labeled microspheres (9 and 15 micron in diameter) that were injected simultaneously into the left atrium. Blood flow was measured 30 minutes after surgical preparation was completed (stage I), 20 minutes after infrarenal aortic cross-clamping (stage II), and 20 minutes after supplemented sodium nitroprusside infusion (stage III). Infrarenal aortic cross-clamping was accompanied by a slight increase in the cardiac output (CO) without significant changes in mean arterial pressure (MAP). Blood flow through the gut, hepatic artery, and cortical layer of the kidneys, as determined with 15-micron spheres, was not changed. Nonentrapment of 9-micron spheres in the gut and renal cortex was increased substantially. Blood flow through the juxtamedullary layer of the kidneys was increased. Sodium nitroprusside supplementation decreased MAP by 30%; CO values returned to baseline level. Hepatic artery blood flow, compared with both baseline values and values during aortic cross-clamping, increased significantly. Blood flow, determined with 15-micron spheres, through the gut and renal cortex did not change, and nonentrapment of 9-micron spheres decreased to baseline values. The data suggest a certain shift of blood flow to the juxtamedullary layer of the kidneys during aortic cross-clamping and normalization of intrarenal blood flow distribution during supplemented sodium nitroprusside infusion. Controlled vasoplegia with sodium nitroprusside may help modify peripheral circulatory disturbances in the kidneys and splanchnic system during infrarenal aortic cross-clamping.     

经食管心脏超声应用于心脏手术患者肾脏血流测定的可行性研究

背景目前尚缺乏可靠的方法监测手术中患者的肾脏血流,本研究中我们评估了经食管心脏超声测定心脏手术患者左肾血流的可行性及可重复性。方法此项前瞻的非干预性研究共纳入了60例心脏手术患者,采用经食管心脏超声技术分别在体外循环前、中、后测定患者的左肾血流。取其中6例患者的超声图,由2位对实验毫不知情的独立评估者在图像采集当时及6个月后再次解读超声图。用变异性及组内相关系数定量计算同一研究者本身与不同研究者之间测量肾血流的可重复性。结果60倒患者中多普勒角度〉30°者（20例）被剔除,成功测量到36例患者的左肾血流。同一研究者与不同研究者的变异性均〈10％,可重复性为良好至极好（组内相关系数为0．604～0．999）,不同时间点（体外循环前、体外循环中和体外循环后）左肾动脉管腔直径为3．8～4．1mm,肾动脉血流速度为25—35cm／s,肾动脉血流量为192—299ml/min。结论在心脏手术患者中,有60％的病例可以通过经食管超声技术测量左肾血流,同一研究者和不同研究者测量肾脏血流的可重复性为良好至极好。     

Nonneurologic morbidity and profound hypothermia in aortic surgery

Background

Use of profoundly hypothermic cardiopulmonary bypass may increase the risk of postoperative bleeding and lung and renal dysfunction. The aim of this study was to analyze postoperative blood loss and indices of pulmonary and renal dysfunction in patients undergoing proximal aortic surgery with and without the use of profound hypothermia to determine risk factors for nonneurologic morbidity.

Methods

Risk factors for blood loss, transfusion requirement, and pulmonary and renal dysfunction were studied in 116 patients undergoing thoracic aortic surgery with profoundly or moderately hypothermic cardiopulmonary bypass.

Results

Overall mortality was 8.6%. Mean (± standard deviation) cardiopulmonary bypass times were 191 ± 53 minutes (profoundly hypothermic group) and 131 ± 48 minutes (moderately hypothermic group; p < 0.0001). The incidence of blood loss more than 1 L or resternotomy for bleeding was 25% (29 patients). Fifteen patients (12.9%) experienced postoperative pulmonary dysfunction, and 25 patients (21.6%) had postoperative renal dysfunction. Forty-one patients (35.3%) had a prolonged intensive therapy unit length of stay. Multivariate analysis demonstrated that prolonged cardiopulmonary bypass time was the only predictor of postoperative hemorrhage and resternotomy for bleeding (p = 0.03). Increased intensive therapy unit length of stay was predicted by total arch replacement (p = 0.01) and low 6-hour ratio of partial pressure of arterial oxygen to inspired fraction of oxygen (p = 0.05). Increased preoperative creatinine (p = 0.002) and emergency status (p = 0.015) predicted postoperative renal dysfunction. Low 6-hour ratio of partial pressure of arterial oxygen to inspired fraction of oxygen was predicted by increased preoperative creatinine (p = 0.03) and prolonged cardiopulmonary bypass time (p = 0.03).

Conclusions

Profound hypothermia may cause a coagulopathy, but procedure extent is the primary determinant of postoperative bleeding. Profoundly hypothermic cardiopulmonary bypass does not appear to be a risk factor for renal or early pulmonary dysfunction or intensive therapy unit length of stay.     

A porcine model of systemic and renal haemodynamic responses to infrarenal aortic cross-clamping.

OBJECTIVES: cross-clamping of the infrarenal aorta is associated with complex haemodynamic disturbances. Several experimental models of aortic cross-clamping (AXC) have been described with heterogeneous results. The main purpose of this study was to establish an animal model in which infrarenal AXC could reproduce similar systemic and renal haemodynamic changes to those observed in humans. METHODS: eleven anaesthetised pigs underwent AXC just below the renal arteries. Renal blood flow was measured using clearance of (131)I hippuran. Systemic and renal parameters were collected at 3 consecutive 30-min periods. RESULTS: AXC did not alter the extraction fraction of (131)I hippuran but was accompanied by significant (13%) decrease in cardiac index (p = 0.005) and a 23% increase in mean arterial pressure (p = 0.005). AXC induced significant 135% increase in renal vascular resistance (p = 0.012) and a 35% decrease in renal blood flow (p = 0.016). This worsened after removal of the aortic clamp, whereas systemic variables returned to baseline levels. CONCLUSIONS: this AXC animal model reproduces the changes observed in humans. It provides a reliable animal model which allows to investigate the underlying mechanisms of renal vasoconstriction and the effect of new drugs.     

RETRACTED: Prevention of renal failure in patients undergoing thoracoabdominal aortic aneurysm repair

OBJECTIVE: Renal failure is a potential complication after thoracoabdominal aortic aneurysm (TAAA) repair and is a significant risk factor for postoperative mortality. We assessed the results of distal aortic perfusion and continuous volume-controlled and pressure-controlled blood perfusion of the kidneys during TAAA repair in patients with preoperative normal and impaired renal function. METHODS: Surgical repair of TAAA was performed in 279 consecutive patients (type I, n = 90; type II, 117; type III, 42; type IV, 30). In 195 patients preoperative renal function was normal; however, in 84 patients renal insufficiency was diagnosed (serum creatinine concentration [SCr], 1.4-2.0 mg/dL, n = 46; SCr, 2.0-2.5 mg/dL, n = 20; and SCr, >2.5 mg/dL, n = 18). Renal perfusion was established with catheters connected to the left-sided heart bypass. Volume flow was assessed with ultrasound, and pressure channels in the catheters enabled pressure- controlled perfusion of the kidneys. RESULTS: Selective renal artery perfusion was achieved in all patients without technical problems or complications. In each catheter, mean arterial pressure was 69 mm Hg and volume flow was 275 mL/min. During aortic cross-clamping, urine output was uninterrupted, irrespective of clamp time. Most patients demonstrated limited or moderate increase in SCr concentration. In 17 patients (6%) SCr doubled, and peaked above 3 mg/dL, but returned to baseline levels within several days. Three patients (1%) required temporary dialysis but were discharged without further need for dialysis. In general, preoperative renal impairment did not worsen. CONCLUSION: Distal aortic and selective renal blood perfusion is an effective measure to protect renal function during TAAA repair, but only if perfusion is provided with adequate volume and pressure. This technique also averts dialysis in most patients with preoperative renal failure.     

Effect of angiotensin converting enzyme inhibition on blood pressure and renal function during open heart surgery

Activation of the renin-angiotensin system during open heart surgery may have consequences both beneficial in sustaining blood pressure and deleterious in compromising renal hemodynamics. The influence of short-term pretreatment with captopril on blood pressure and renal function was assessed double-blind versus placebo in 18 patients without pre-existing cardiac or renal failure, and undergoing coronary artery bypass. No difference in blood pressure and fluid requirement during the surgical period was observed between groups receiving captopril or placebo. Effective renal plasma flow and glomerular filtration rate decreased in the placebo group whereas they remained unaltered in the captopril group; during cardiopulmonary bypass, urinary excretion of sodium was greater in patients receiving captopril than those receiving placebo. These results suggest that captopril pretreatment does not compromise the control of blood pressure and renal function during open heart surgery; additional studies on the protective value of angiotensin-converting enzyme inhibitors are warranted in patients at higher risk for developing renal failure.     

A single-center experience treating renal malperfusion after aortic dissection with central aortic fenestration and renal artery stenting

OBJECTIVE: Patients with aortic dissection were studied to define (1) anatomic and physiologic derangements in renal artery blood flow, (2) differences in clinically suspected renal malperfusion and true functional malperfusion, and (3) variations in endovascular interventions for the treatment of renal malperfusion. METHODS: The cohort comprised 165 patients (mean age, 58 years) with dissections who were thought to have malperfusion sufficient to require arteriography. They were treated from 1996 to 2004 for acute (n = 115) or chronic (n = 50) aortic dissections (75 had type A, 90 had type B lesions). All patients had suspected peripheral vascular malperfusion (ie, cerebral, spinal, mesenteric, renal, or lower extremity vascular beds). Renal malperfusion was suspected in 88 patients secondary to worsening hypertension (n = 34), evolving renal insufficiency (n = 37), computed tomography evidence of impaired renal blood flow (n = 13), or a combination of factors (n = 4). Patients underwent angiographic and intravascular ultrasound studies. Renal malperfusion was confirmed with a systolic gradient between the aortic root and renal hilum (average, 44 mm Hg). RESULTS: Right renal arteries arose exclusively from the true lumen in 115 patients (70%), the false lumen in 11 (7%), and both lumens in 37 (23%). Left renal arteries arose exclusively from the true lumen in 69 patients (42%), the false lumen in 32 (20%), and both lumens in 62 (38%). Angiographic confirmation of malperfusion existed in 59 patients (67%) of the 88 suspected of such, and in 31 patients (39%) of the 79 with suspected malperfusion of nonrenal tissues. Of the 90 patients with confirmed renal malperfusion, 71 underwent endovascular therapy, including isolated renal artery stenting (n = 31), as well as proximal aortic fenestration with or without aortic stenting (n = 24), or both renal and aortic intervention (n = 16). Residual pressure gradients averaged 8.1 mm Hg after these interventions. Five procedure-related complications (7%) occurred. The periprocedural postintervention mortality rate was 21% (n = 15), including multisystem organ failure (n = 7), false lumen rupture (n = 3), reperfusion injury (n = 2), cerebral ischemia (n = 1), cardiac arrest (n = 1), and unknown (n = 1). CONCLUSIONS: Percutaneous aortic fenestration and renal artery stenting are both technically feasible and associated with an acceptable complication rate. Most patients respond well symptomatically, obviating the need for immediate surgical relief of renal artery obstruction and allowing for renal malperfusion recovery.     

Abdominal aortic coarctation and segmental hypoplasia.

Functionally significant, nonatherosclerotic, noninflammatory, concentric and tubular stenoses of the abdominal aorta, 4 to 16 cm in length, were encountered in five male and five female patients 11 to 49 years old. Seven patients were younger than 19 years of age. Aortic branch stenoses were common, affecting splanchnic vessels in seven patients and renal arteries in eight patients. The pathogenesis of the aortic constrictive lesions remains unknown, but it may be related to developmental error or aortic growth arrest. Existence of multiple renal arteries in 70% of these patients lends support to the developmental hypothesis. Intimal fibroplasia characterized stenotic aortic tissue. Severe hypertension was common, with the mean preoperative arterial pressure being 200/119 mm Hg. Thoracoabdominal bypass was undertaken in eight patients, being combined with renovascular reconstruction on five occasions. Two patients underwent patch graft aortoplasty with bilateral renal revascularization. Therapeutic results were classified as excellent six times and as good four times. Single-stage arterial reconstructions are the preferred method of treatment for abdominal aortic coarctation or segmental hypoplasia with associated aortic branch disease.     

Renal vasoconstriction and transient declamp hypotension after infrarenal aortic occlusion: role of plasma purine degradation products

To better understand renal and systemic hemodynamics associated with hindquarter ischemia produced by aortic compression, chloralose-anesthetized dogs were given phentolamine while an external clamp maintained infrarenal aortic pressure below 25 mm Hg for 45 minutes. In four sham-operated dogs, infrarenal pressure was maintained; reinforced cannulas, capable of resisting clamp compression, were placed within the aorta and the inferior vena cava. Suprarenal and infrarenal arterial pressure and renal blood flow were continuously monitored. Blood samples taken before clamp application and at 1, 3, 5, and 10 minutes after clamp removal were assayed for adenosine, inosine, xanthine, and hypoxanthine. On clamp removal suprarenal pressure immediately dropped from a preclamp pressure of 114 to 82 mm Hg but returned to preclamp values within 1 minute. Renal blood flow was significantly reduced after clamp release, reaching a nadir of 39% of preclamp flow. This reduction persisted despite a normalization of arterial pressure. Summed plasma purines were significantly elevated 1 minute after clamp removal. Sham-operated dogs showed no significant alterations in arterial pressure, renal blood flow, or plasma purine levels. This study demonstrates a significant non-alpha-adrenergic receptor-mediated reduction in renal blood flow and a coincident increase in purine degradation products after removal of an infrarenal aortic cross-clamp.     

Simultaneous aortic prosthesis implantation and renal transplantation

A 44 year old man with end-stage renal failure from nephro-angiosclerosis and with an abdominal aortic aneurysm involving also the common iliac arteries simultaneously underwent an abdominal aneurysmectomy using a standard Dacron graft and a living related renal transplantation. An original technic was used in order to prevent an anastomotic stenosis of the artery: the donor's renal artery was sutured end- to side on the Dacron prosthesis via a venous patch from the donor's renal vein. The post-operative course was uncomplicated; one year after the operation, the renal function is excellent (creatine: 1.6 mg/dl) and the blood pressure is normal.     

The Benefits of High‐flow Management in Children With Pulmonary Atresia

The high‐flow management of cardiopulmonary bypass (CPB; ≥2.4 L/min/m²) is a standard strategy used at this institute for children with pulmonary atresia (PA) due to a fear that the blood flow may be diverted by the major/minor aortopulmonary‐collateral‐arteries and hypervascularization due to long‐term hypoxia. The purpose of this study was to describe the validity of high‐flow management in children with PA. The CPB records of 23 children with PA who underwent a definitive biventricular repair between Feb 2006 and Nov 2008 were retrospectively reviewed. The mean age at the operation was 33 ± 22 months. The blood‐pressure during bypass was controlled with the same protocol. The mean cooling‐temperature was 28.4 ± 3.7°C. The mean minimum hematocrit was 25.0 ± 3.4%. The mean maximum bypass flow index at the initiation, the mean maximum flow index during aortic cross‐clamping, the mean minimum flow index during aortic cross‐clamping, and the mean maximum flow index after rewarming were 3.1 ± 0.5, 3.1 ± 0.5, 2.6 ± 0.4, and 3.2 ± 0.4 L/min/m², respectively. The higher bypass flow indexes significantly correlated with the lower serum lactate levels. The lowest oxygen delivery during CPB had significant influences on the urine output during bypass (R = 0.547, P = 0.007), the serum lactate levels at the end of CPB (R = ?0.442, P = 0.035), and the postoperative thoracic effusion (R = ?0.459, P = 0.028). A bypass flow index of 2.4 L/min/m² may not be sufficient and the maximum requirement of bypass flow index may be 3.2 L/min/m² or more in this patient population.     

开放手术治疗近肾腹主动脉闭塞的临床分析

背景与目的 近肾腹主动脉闭塞属于主髂动脉闭塞的极端情况,治疗相对棘手。尽管腔内治疗适用于此类患者,开放手术治疗仍有其适应证所在。本研究分析近肾腹主动脉闭塞患者行开放手术治疗的效果,并总结经验及其治疗策略。方法 收集首都医科大学附属北京天坛医院血管外科2018年7月—2022年5月期间行开放手术治疗的10例近肾腹主动脉闭塞患者的临床资料。回顾性分析患者的一般资料、手术方式、手术时间、术中出血量、腹主动脉阻断方式、肾上腹主动脉阻断时间、手术并发症、症状缓解程度及随访结果。结果 10例患者手术均顺利完成。手术时间210~420 min,中位手术时间为265 min;术中出血200~1 200 mL,中位出血量375 mL。3例行膈下腹主动脉-双股动脉人工血管搭桥术,其中1例同时行右膝上截肢术;1例行膈下腹主动脉-双髂总动脉人工血管搭桥术,同时重建肠系膜下动脉;5例行肾下腹主动脉-双股动脉人工血管搭桥术;1例行腋动脉-双股动脉人工血管搭桥术并左颈动脉内膜剥脱术。膈下腹主动脉阻断4例,肾上肾下序贯腹主动脉阻断1例,肾下腹主动脉阻断4例。肾上腹主动脉阻断时间14~20 min,中位阻断时间20 min。围手术期无心脑血管意外、死亡、肾功能障碍及人工血管感染发生。10例患者术后双下肢间歇性跛行或静息痛症状均消失,双侧足背或胫后动脉搏动均可扪及。10例患者获随访4~40个月,中位随访时间27个月,随访期间桥血管均通畅、吻合口无狭窄、无下肢及肠道缺血表现。结论 近肾腹主动脉闭塞患者行开放手术治疗效果确切,桥血管远期通畅率高,需根据患者不同情况采取个体化的治疗方式。     

Renal perfusion during thoracoabdominal aortic operations: cold crystalloid is superior to normothermic blood

BACKGROUND: Renal failure remains a common complication of thoracoabdominal aortic aneurysm repair. The purpose of this randomized clinical trial was to compare two methods of selective renal perfusion--cold crystalloid perfusion versus normothermic blood perfusion--and determine which technique provides the best kidney protection during thoracoabdominal aortic aneurysm repair. METHODS: Thirty randomized patients undergoing Crawford extent II thoracoabdominal aortic aneurysm repair with left heart bypass had renal artery perfusion with either 4 degrees C Ringer's lactate solution (14 patients) or normothermic blood from the bypass circuit (16 patients). Acute renal dysfunction was defined as an elevation in serum creatinine level exceeding 50% of baseline within 10 postoperative days. RESULTS: One death occurred in each group. One patient in the blood perfusion group experienced renal failure requiring hemodialysis. Ten patients (63%) in the blood perfusion group and 3 patients (21%) in the cold crystalloid perfusion group experienced acute renal dysfunction (p = 0.03). Multivariable analysis confirmed that the use of cold crystalloid perfusion was independently protective against acute renal dysfunction (p = 0.02; odds ratio, 0.133). CONCLUSIONS: When using left heart bypass during repair of extensive thoracoabdominal aortic aneurysms, selective cold crystalloid perfusion offers superior renal protection when compared with conventional normothermic blood perfusion.     

Renal and aortic localizations in Takayasu's disease

AIM OF THE STUDY: The aim of this work was to study the localizations of Takayasu's disease to the aorta and the renal arteries, the long-term results of their surgical treatment and the evolution of the disease with time. PATIENTS AND METHODS: From 1972 to 2000, 23 patients (16 females, 7 males) with aortic and/or renal lesions were operated on. Mean age was 19.5 +/- 12.4 years. Despite heavy medical treatment, all had severe and uncontrollable hypertension. Eighteen patients had associated lesions of the aorta and renal arteries, 5 had isolated lesions of the renal artery, 10 had lesions of mesenteric arteries, 6 had lesions of supra-aortic trunks. Percutaneous transluminal angioplasty of the renal artery (ies) was attempted in 4 cases and was unsuccessful in all. Due to bilateral lesions in 12 patients, the surgical treatment consisted of 3 nephrectomies and 32 artery repairs of which 23 were performed by conventional in situ surgery and 9 by extracorporeal repair. An aortic bypass was performed in 7 patients and revascularization of other visceral arteries in 3. The follow-up extends from 1 to 18 years (mean: 5). RESULTS: There was no mortality. Three postoperative thromboses of repairs occurred: 2 of renal artery and 1 of mesenteric artery. Immediate results on blood pressure control were as follows: complete cure in 18 patients (78%), improvement in 3 (13%) and failure in 2 (9%). During the follow-up, evolution of the disease was observed in 10 patients (43%): 4 repeat stenoses of renal arteries due to aggravation of aortic lesions requiring reoperation in 2 patients, 3 aggravation of aortic lesions requiring an aortic bypass in 1 patient, 1 coronary insufficiency requiring a coronary bypass at 8.5 years. During the long-term follow up, due to secondary anatomical deteriorations, the results of surgery on blood pressure control were as follow: complete cure in 14 patients (61%), improvement in 4 (17%), failure in 5 (22%). CONCLUSION: Surgical treatment of reno-aortic lesions in Takayasu's disease must be reserved to patients whose arterial hypertension is uncontrollable despite heavy medical treatment. Results are altered by the evolution of the disease either locally or in other territories and that may require several operations. Due to frequently occurring late degeneration of repairs, surgical therapy must be carefully decided and patients' follow-up must be prolonged.     

The effects of a leukocyte-depleting filter on cerebral and renal recovery after deep hypothermic circulatory arrest

OBJECTIVE: The purpose of this study was to determine the effects of a leukocyte-depleting filter on cerebral and renal recovery after deep hypothermic circulatory arrest. METHODS: Sixteen 1-week-old piglets underwent cardiopulmonary bypass, were cooled to 18 degrees C, and underwent 60 minutes of circulatory arrest, followed by 60 minutes of reperfusion and rewarming. Global and regional cerebral blood flow, cerebral oxygen metabolism, and renal blood flow were determined before cardiopulmonary bypass, after the institution of cardiopulmonary bypass, and at 1 hour of deep hypothermic circulatory arrest. In the study group (n = 8 piglets), a leukocyte-depleting arterial blood filter was placed in the arterial side of the cardiopulmonary bypass circuit. RESULTS: With cardiopulmonary bypass, no detectable change occurred in the cerebral blood flow, cerebral oxygen metabolism, and renal blood flow in either group, compared with before cardiopulmonary bypass. In control animals, after deep hypothermic circulatory arrest, blood flow was reduced to all regions of the brain (P <.004) and the kidneys (P =.02), compared with before deep hypothermic circulatory arrest. Cerebral oxygen metabolism was also significantly reduced to 60.1% +/- 11.3% of the value before deep hypothermic circulatory arrest (P =.001). In the leukocyte-depleting filter group, the regional cerebral blood flow after deep hypothermic circulatory arrest was reduced, compared with the value before deep hypothermic circulatory arrest (P <.01). Percentage recovery of cerebral blood flow was higher in the leukocyte filter group than in the control animals in all regions but not significantly so (P >.1). The cerebral oxygen metabolism fell to 66.0% +/- 22.3% of the level before deep hypothermic circulatory arrest, which was greater than the recovery in the control animals but not significantly so (P =.5). After deep hypothermic circulatory arrest, the renal blood flow fell to 81.0% +/- 29.5% of the value before deep hypothermic circulatory arrest (P =.06). Improvement in renal blood flow in the leukocyte filter group was not significantly greater than the recovery to 70.2% +/- 26.3% in control animals (P =.47). CONCLUSIONS: After a period of deep hypothermic circulatory arrest, there is a significant reduction in cerebral blood flow, cerebral oxygen metabolism, and renal blood flow. Leukocyte depletion with an in-line arterial filter does not appear to significantly improve these findings in the neonatal piglet.     

Bench repair of complex renal arterial lesions

Between 1968 and 1989, 160 patients underwent aortorenal bypass for renovascular hypertension. During the same interval, 13 patients had ex-vivo bench repair of complex renal arterial pathology. There were eight men and five women, with a mean age of 36 years. Twelve of the 13 patients had fibromuscular disease; one had atherosclerosis. Twelve patients had renovascular hypertension with complex stenotic disease beyond the main renal artery. Seven of these also had an associated renal aneurysm as did the sole normotensive patient. Saphenous vein patch or bypass were used to correct stenotic segments in four patients, while the remaining nine patients had excision of stenotic or aneurysmal segments with primary arterial anastomosis. There were no deaths in the series. One kidney was lost because of arterial thrombosis. One patient required reoperation to control postoperative bleeding. Nine of the 12 patients with renovascular hypertension were normotensive off medication, and three were improved, with reduced medication controlling their blood pressure. Ureteric obstruction occurred in two patients; this settled spontaneously in one patient and was corrected by reoperation in the other. From this experience, we conclude that bench repair is a safe and effective way to maximize salvage of kidneys affected by complex arterial pathology.Presented at the Fifteenth Annual Meeting of the Peripheral Vascular Surgery Society, June 2, 1990, Los Angeles, California.