Efficacy and frequency of cerebrospinal fluid drainage in operative management of thoracoabdominal aortic aneurysms.

BACKGROUND: Paraplegia remains the most dreaded complication following thoracoabdominal aortic repair. We investigated the efficacy of cerebrospinal fluid drainage as a spinal cord-protecting modality. We also evaluated the correlation between the frequency of cerebrospinal fluid drainage and the Crawford classification. METHODS: Spinal cord function was monitored during 20 open surgical procedures (group I) and 27 stent-graft implantations (group II). Evoked potentials and intracranial pressure were monitored in each operation. If intracranial pressure exceeded 15 mmHg, cerebrospinal fluid was drained. RESULTS: Cerebrospinal fluid drainage was necessary in 75 % of patients in group I (Crawford type I: 33 %, type II: 40 %, type III: 20 %, type IV: 7 %) and in 22 % of patients in group II (Crawford type I: 33 %, type II: 66 %). Evoked potential alterations correlated with an increase in intracranial pressure. Timely cerebrospinal fluid drainage reversed these changes in 72 %. Three patients remained paraplegic. CONCLUSION: Cerebrospinal fluid drainage is a valuable neuroprotective interventional tool to lower the risk of spinal cord ischemia. The combination of neurophysiological monitoring and cerebrospinal fluid drainage optimizes the prevention of paraplegia during aortic repair.

Actual management of patients with familial ascending aortic aneurysms and type-A aortic dissections.

BACKGROUND: There are few families with the diagnosis of ascending aortic aneurysm and acute type-A aortic dissection inherited as an autosomal-dominant disorder in the absence of a known genetic syndrome. METHODS: We investigated a family with 26 members in whom ascending aortic aneurysms and acute type-A aortic dissections occurred over three generations. Examinations were performed to identify family members at specific risk. RESULTS: Six members presented with acute type-A aortic dissections and three relatives had ascending aortic aneurysms. Clinical examinations showed no characteristics of a known genetic syndrome. Molecular genetic analysis revealed no mutations known to cause a form of autosomal-dominant inherited aortic disease. CONCLUSION: Adequate diagnostic measures are mandatory in families with ascending aortic aneurysms or type-A aortic dissections to identify or exclude family members at risk for aortic diseases. Even in the absence of identifiable mutations causing isolated aortic aneurysms or aortic dissections, we recommend standardised examinations of all first-degree relatives of affected families. An indication for prophylactic aortic root replacement should be considered for patients at risk.

Evaluation of three different measurement methods for dural ectasia in Marfan syndrome.

AIM: Dural ectasia is a major diagnostic criterion for Marfan syndrome using the Ghent nosology. Our aim was to evaluate the efficacy of three different radiological methods previously proposed for the assessment of dural sac diameter in Marfan syndrome. METHODS: Marfan syndrome was diagnosed in our study using the Ghent criteria, disregarding dural ectasia as a criterion. Three proposed radiological methods were applied to measure dural sac diameter, examined for 41 patients (18 patients with and 23 without Marfan syndrome) by computed tomography or magnetic resonance imaging. RESULTS: Using Oosterhof's method, 94% of the patients with and 44% of the patients without Marfan syndrome fulfilled the criteria of dural ectasia. According to Villeirs, dural ectasia was diagnosed in 18% of the patients with and in none of the patients without Marfan syndrome. With Ahn's method, dural ectasia was found in 72% of the patients with and in 44% of the patients without Marfan syndrome. In only two patients with Marfan syndrome was dural ectasia diagnosed by all three methods. CONCLUSION: Our results reveal overt discrepancy between the three methods of assessing dural ectasia. Considering the key role played by dural ectasia in reinforcing the diagnosis of Marfan syndrome according to the Ghent nosology, a standardized and reliable method should be sought.

Development of a special balloon occlusion device to prevent adverse events in high-risk patients during open aortic surgery.

OBJECTIVE: To prevent clamp injury that may occur during aortic surgery, we aimed to develop a special balloon occlusion (BO) device to lower the thromboembolic risk in patients with severe atherosclerosis during aortic aneurysm repair. METHODS: The study comprised two test phases: a laboratory-testing series focussing on flexible artificial aortas, and an experimental series conducted on 10 pigs. RESULTS: The device proved to be effective during the laboratory tests and the experiments on pigs. No complications such as intraoperative balloon rupture, dislocation, or occlusion leaks occurred. No damage to the aortic vessels was observed in further histological examinations. CONCLUSIONS: This BO device has the potential to become an alternative to cross-clamping for vascular surgeons in patients with severely atherosclerotic vessels.

Thoracoabdominal aortic aneurysm repair: interplay of spinal cord protecting modalities.

BACKGROUND: The purpose of this study was to assess the complementary use of different methods of measuring spinal cord perfusion during thoracoabdominal aortic surgery. METHODS: The spinal cords of 28 patients undergoing surgery on the thoracoabdominal aorta were monitored with transcranial electrical stimulation (tcMEP) and somatosensory-evoked potentials (SSEP). Available approaches of spinal cord-protection included: Moderate systemic hypothermia, constant cerebrospinal fluid (CSF) drainage and pressure monitoring, reimplantation of segmental arteries, cardiopulmonary bypass (CPB), and staged clamping. RESULTS: Fourteen of 19 patients (75%) undergoing open surgical treatment (Group I) exhibited loss of tcMEP after proximal aortic clamping. In nine cases (47%), we observed recovery of tcMEP after intraoperative interventions, while two patients subsequently developed paraplegia and three died. Seventeen of 19 patients showed loss of SSEP, with recovery in 12 cases (63%). During stent-graft implantation (Group II), one of nine patients (11%) demonstrated tcMEP loss with intraoperative, intervention-related recovery. The SSEP-recording course remained stable. CONCLUSIONS: tcMEP/SSEP monitoring has proved to be an excellent means of detecting spinal cord ischaemia during surgery on thoracoabdominal aortic aneurysms. The prognostic value of tcMEP monitoring should be considered superior to that of SSEP measurements, because of its direct and rapid response to spinal malperfusion. Through combined neurophysiological monitoring, vital parameter balancing and intraoperative interventions, spinal cord perfusion improves and recovery of tcMEP and SSEP is achievable, reducing the prevalence of postoperative paraplegia.

Improved spinal cord perfusion during thoracoabdominal aortic repair.

OBJECTIVES: The study's aim is to evaluate whether intraoperative neurophysiological monitoring with transcranial motor-evoked potentials (tcMEP) permits early recognition of neuronal lesions, thus making interventions to prevent irreversible spinal cord damage possible. MATERIAL AND METHODS: TcMEP monitoring was carried out in twelve patients (mean age 60 years) during open surgical thoracoabdominal aortic replacement. Current approaches for corrective, spinal cord-protecting interventions consist of: raising distal perfusion by increasing cardiopulmonary bypass (CPB) flow, catecholamine application, reducing central venous pressure, reimplantation of segmental arteries, and cerebrospinal fluid (CSF) drainage. RESULTS: Nine patients exhibited loss of tcMEP after segmental aorta clamping. In five patients we observed a recovery of tcMEP through counteractive measures. Three patients died intraoperatively, one patient presented with postoperative paraplegia and loss of tcMEP. CONCLUSION: TcMEP loss is associated with spinal cord ischaemia, causing postoperative paraplegia. TcMEP monitoring is an excellent method to detect spinal cord ischaemia at an early stage.

Microperfusion enhancement after TMLR in chronically ischemic porcine hearts.

OBJECTIVE: The purpose of this study was to determine the effect of transmyocardial laser revascularization (TMLR) on myocardial perfusion and function in chronically ischemic myocardium. METHODS: In the first operation a stenosis of the left anterior descending artery was created in 20 open-chest anesthetized pigs to implement this ischemic model. In contrast, four pigs served as controls (thoracotomy only). Seven days later (2nd operation), all animals were studied at baseline by analyzing different parameters of perfusion (radioactive microspheres), function, and intramyocardial pressure. Afterwards, pigs who received a left anterior descending artery stenosis were randomized into one of three groups: animals in laser group 1 (n=7) received one and in laser group 2 (n=7) two laser channels per cm(2) in the left anterior descending artery territory. Animals of the ischemic group (n=6) underwent the same procedures without transmyocardial laser revascularization. Three months later, the animals were re-studied (3rd operation) and additional analysis of histochemistry and myocardial water content was performed. RESULTS: Regional myocardial blood flow (RMBF) in laser group 2 revealed statistically higher RMBF values compared to the ischemic group (0.39+/-0.13 versus 0.14+/-0.12 ml/min/g; P=0.043), after 3 months, whereas the absolute RMBF had not increased compared to the 1-week baseline values. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared to the initial values in all study groups (P=ns). Nevertheless, laser group 1 demonstrated relatively higher LVSWI(max) values compared to the ischemic (1.33+/-0.19 versus 0.93+/-0.16 mJ/kg; P=0.03) and laser group 2 (1.33+/-0.19 versus 1.02+/-0.15; P=0.024). Regional contractility of laser groups 1 and 2 recovered after 3 months (which had deteriorated shortly after transmyocardial laser revascularization) and increased under stress (100% versus 144.33+/-46.42, P=0.029 and 100% versus 116.26+/-21.06, P=0.034; respectively). In contrast, the corresponding ischemic group values were not different from initial values (P=ns). CONCLUSIONS: This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly improves microperfusion and regional function, whereas the overall perfusion and global LV function is unchanged.

Evaluation of the indirect revascularization method after 3 months chronic myocardial ischemia.

OBJECTIVE: The long-term effectiveness of transmyocardial laser revascularization (TMLR) was evaluated in the setting of a severe left anterior descending artery (LAD) stenosis. METHODS: To employ the chronic ischemic model, pigs underwent three operative procedures over a 13-week period. In the first operation, an operative stenosis of the LAD was created. One week later, the animals were studied at baseline by analyzing different parameters of perfusion (microspheres), function and ECG changes. Afterwards, pigs were randomized into one of three different experimental groups: animals in laser group 1 received one laser channel (n=9) and laser group 2 two channels per cm(2) (n=6) in the LAD territory (using a CO(2)-laser). Animals of the ischemic group (n=12) underwent the same procedures without TMLR-treatment. Twelve weeks later, the animals were re-studied (third operation) and killed. Additional analysis of myocardial water content and histochemistry was performed. RESULTS: Chronic myocardial ischemia and regional myocardial blood flow (RMBF) in laser group 2 revealed relatively higher RMBF values compared with the ischemic group (P=0.015), after 3 months, but no absolute improvement of perfusion at rest compared with baseline was observed in all experimental groups. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared with initial values in all study groups (P not significant). However, laser group 1 demonstrated relatively higher LVSWI(max) values in comparison with the ischemic group (P=0.013) as did laser group 2 (P=0.017). Regional contractility of the laser groups recovered after 3 months (which was deteriorated shortly after TMLR, P<0.001) and increased under stress compared with baseline (laser 1: P=0.015, laser 2: P=0.017). In contrast, the ischemic group did not show any difference from initial values (P not significant). The lased pigs of group 2 were less prone to intractable ventricular fibrillation (P=0.036 vs. ischemic group), and showed a significant smaller area of necrosis in the area at risk (P=0.012 vs. ischemic group). CONCLUSIONS: This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly ameliorates microperfusion and regional contractility, and diminishes the incidence of ventricular fibrillation and necrosis in the area at risk. However, it does not change the overall perfusion and global LV function.