Generalized dilating diathesis in patients with popliteal arterial aneurysm

BACKGROUND: Aim of this study was to analyse the relationship between popliteal artery aneurysm (PAA) and generalized arteriomegaly. PATIENTS AND METHODS: In this consecutive serie, thirty-three patients (1 woman, mean age 69.7 +/- 9.6 years) undergoing PAA repair between 1996 and 2000 agreed to participate in a duplex screening program to assess the diameters of the infrarenal abdominal aorta, common and external iliac, common and superficial femoral and contralateral popliteal arteries as well as common carotid and brachial arteries. RESULTS: The prevalence of arteriomegaly and aneurysmal disease, respectively, was as follows: abdominal aorta 15/33 (45.5%) and 8/33 (24.2%), common iliac artery 34/66 (51.5%) and 23/66 (34.8%), common femoral artery 55/66 (83.3%) and 7/66 (10.6%) as well as contralateral popliteal artery 7/33 (21.2%) 15/33 (45.5%). Significantly larger carotid artery diameters were found comparing PAA patients with age- and body surface adjusted healthy controls (p < 0.001). Furthermore, patients with multiple peripheral arterial aneurysms had significantly larger diameters of the brachial (p < 0.02) and external iliac (p < 0.005). CONCLUSIONS: Our findings support the hypothesis of a diathesis for a generalized arteriomegaly with a predilection for further aneurysms of the abdominal aorta, iliac arteries, femoral and contralateral popliteal arteries in patients with PAA.

Postmortem radiology of fatal hemorrhage: measurements of cross-sectional areas of major blood vessels and volumes of aorta and spleen on MDCT and volumes of heart chambers on MRI

OBJECTIVE: Autopsy determination of fatal hemorrhage as the cause of death is often a difficult diagnosis in forensic medicine. No quantitative system for accurately measuring the blood volume in a corpse has been developed. MATERIALS AND METHODS: This article describes the measurement and evaluation of the cross-sectional areas of major blood vessels, of the diameter of the right pulmonary artery, of the volumes of thoracic aorta and spleen on MDCT, and of the volumes of heart chambers on MRI in 65 autopsy-verified cases of fatal hemorrhage or no fatal hemorrhage. RESULTS: Most cases with a cause of death of "fatal hemorrhage" had collapsed vessels. The finding of a collapsed superior vena cava, main pulmonary artery, or right pulmonary artery was 100% specific for fatal hemorrhage. The mean volumes of the thoracic aorta and of each of the heart chambers and the mean cross-sectional areas of all vessels except the inferior vena cava and abdominal aorta were significantly smaller in fatal hemorrhage than in no fatal hemorrhage. CONCLUSION: For the quantitative differentiation of fatal hemorrhage from other causes of death, we propose a three-step algorithm with measurements of the diameter of the right pulmonary artery, the cross-sectional area of the main pulmonary artery, and the volume of the right atrium (specificity, 100%; sensitivity, 95%). However, this algorithm must be corroborated in a prospective study, which would eliminate the limitations of this study. Quantitative postmortem cross-sectional imaging might become a reliable objective method to assess the question of fatal hemorrhage in forensic medicine.

Outcome and quality of life in patients treated for abdominal aortic aneurysms: a single center experience

BACKGROUND: Durability of protection and long-term quality of life (QoL) are critical outcome parameters of abdominal aortic aneurysm (AAA) repair. The aim of the present study was to compare results of endovascular and open aneurysm repair (EVAR and OR) with adjusted standard populations, including stratification for urgency of presentation. METHODS: Retrospective analysis of prospectively collected data of 401 consecutive patients presenting with AAA between January 1998 and December 2002. Cross-sectional follow up was 58 +/- 29 months. Patients were grouped into three cohorts: elective EVAR (n = 68), elective OR (n = 244), and emergency OR (including symptomatic and ruptured AAA, n = 89). Endpoints were perioperative (i.e., 30 days or in-hospital) and late mortality rates, as well as long-term QoL as assessed by the Short Form health survey questionnaire (SF-36). RESULTS: Mean age was lower in the elective OR cohort (66 +/- 10 years) than in the EVAR cohort (72 +/- 7 years; p < .05). Perioperative mortality rates were 4.4%, 0.4%, and 10.1%, for the EVAR, elective OR, and emergency OR cohorts, respectively (p < .05). Corresponding cumulative survival rates after 4 years were 67%, 89%, and 69%, respectively. Long-term QoL SF-36 scores were in all cohorts similar to age- and gender-adjusted standard populations, which score between 85 and 115: 99.6 +/- 35.8 (EVAR), 101.3 +/- 32.4 (elective OR), and 100.4 +/- 36.5 (emergency OR). CONCLUSIONS: Long-term QoL is not permanently impaired after AAA repair, but returns in long-term survivors to what would be expected in a standard population. In this respect, differences were found neither between EVAR and OR, nor between elective and emergency repair. Perioperative mortality rates were highest in patients undergoing emergency OR. The outlook for such patients after the perioperative period, however, was similar to that for patients undergoing elective repair.

A new surgical approach for exclusion of renal artery aneurysms avoiding organ ischemia

INTRODUCTION: Surgical treatment of renal artery aneurysms is inevitably associated with temporary renal artery occlusion and risk of ischemic injury. We present a technique for renal artery grafting and aneurysm exclusion without interrupting renal blood flow. REPORT: A symptomatic renal artery aneurysm was bypassed with a venous graft between the abdominal aorta and the very distal renal artery utilizing a distal anastomotic device without interruption of renal blood flow. The aneurysm was then excluded by means of hemostatic clips. CONCLUSION: The presented surgical technique offers the major advantage of avoiding organ ischemia and accelerating the surgical procedure.

Effects of Thoratec pulsatile ventricular assist device (PVAD) timing on the abdominal aortic wave intensity pattern

Arterial waves are seen as possible independent mediators of cardiovascular risks, and the wave intensity analysis (WIA) has therefore been proposed as a method for patient selection for ventricular assist device (VAD) implantation. Interpreting measured wave intensity (WI) is challenging and complexity is increased by the implantation of a VAD. The waves generated by the VAD interact with the waves generated by the native heart, and this interaction varies with changing VAD settings. Eight sheep were implanted with a pulsatile VAD (PVAD) through ventriculo-aortic cannulation. The start of PVAD ejection was synchronized to the native R-wave and delayed between 0 % - 90 % of the cardiac cycle in 10 % steps or phase shifts (PS). Pressure and velocity signals were registered, using a combined Doppler and pressure wire positioned in the abdominal aorta, and used to calculate the WI. Depending on the PS, different wave interference phenomena occurred. Maximum unloading of the left ventricle (LV) coincided with constructive interference and maximum blood flow pulsatility, and maximum loading of the LV coincided with destructive interference and minimum blood flow pulsatility. We believe, that non-invasive WIA could potentially be used clinically to assess the mechanical load of the LV, and to monitor the peripheral hemodynamics such as blood flow pulsatility and risk of intestinal bleeding.

Single-center experience in the management of spontaneous isolated abdominal aortic dissection

OBJECTIVE This study aims to report the management of patients with spontaneous isolated dissection of the abdominal aorta (sIAAD). METHODS A cohort of 18 consecutive patients (12 male, mean age 58 years) with sIAAD was treated between 1990 and 2009. Dissection was asymptomatic in ten and symptomatic in eight patients. Retrospective data analysis from patient charts was performed. Follow-up included clinical examination, ultrasound, and/or CT-angiography. Mean follow-up was 54 months (range 1-211). RESULTS In total, eight out of 18 received invasive treatment. All asymptomatic patients initially underwent conservative treatment and surveillance. Spontaneous false lumen thrombosis occurred in four (40 %), and three patients showed relevant aneurysmatic progression and underwent elective invasive treatment (open n = 2, endovascular n = 1), representing a crossover rate of 30 %. Late mortality was 20 % (n = 2) in this group. In symptomatic patients, five underwent urgent treatment due to persistent abdominal or back pain (n = 4) or contained rupture (n = 1); one was treated for claudication. The remaining two patients presented with irreversible spinal cord ischemia and were treated conservatively. Three patients were treated by open surgery and three by endovascular interventions (two stentgrafts, one Palmaz XXL stent). Early and late morbidity and mortality was 0 % in this group. There were no reinterventions CONCLUSION: The majority of patients with sIADD require invasive treatment, with EVAR being the preferable treatment option today. In asymptomatic IADD, primary surveillance is justifiable, but close surveillance due to expansion is necessary.

[Aortic aneurysms and aortic dissection : Epidemiology, pathophysiology and diagnostics.]

Aortic aneurysms and aortic dissection represent a significant health risk due to the demographic developments and current life styles. The mortality of ruptured aortic aneurysms is up to 80 % and the prevalence of aneurysms varies depending on the localization (thoracic or abdominal). Most commonly affected is the infrarenal abdominal aorta; however, there is evidence that the prevalence is diminishing but in contrast the incidence of thoracic aortic aneurysms is increasing. Aortic dissection is often fatal and is the most common acute aortic disease but the incidence is presumed to be underestimated. The pathogenesis of aortic aneurysms is manifold and is based on an interplay between degenerative, proteolytic and inflammatory processes. An aortic dissection arises from a tear in the intima which results in a separation of the aortic wall layers with infiltration of bleeding and the danger of aortic rupture. Various genetic disorders of connective tissue promote degeneration of the aortic media, most notably Marfan syndrome. Risk factors for aortic aneurysms and aortic dissection are nicotine abuse, arterial hypertension, age and male gender. Aortic aneurysms initially have an uneventful course and as a consequence are mostly discovered incidentally. The clinical course and symptoms of aortic dissection are very much dependent on the section of the aorta affected and the manifestations are manifold. Acute aortic dissection is in 80 % of cases first manifested as sudden extremely severe pain. The diagnostics and subsequent course control can be achieved by a variety of imaging procedures but the modality of choice is computed tomography.

Rationale, scope, and 20-year experience of vascular surgical training with lifelike pulsatile flow models

Vascular surgical training currently has to cope with various challenges, including restrictions on work hours, significant reduction of open surgical training cases in many countries, an increasing diversity of open and endovascular procedures, and distinct expectations by trainees. Even more important, patients and the public no longer accept a "learning by doing" training philosophy that leaves the learning curve on the patient's side. The Vascular International (VI) Foundation and School aims to overcome these obstacles by training conventional vascular and endovascular techniques before they are applied on patients. To achieve largely realistic training conditions, lifelike pulsatile models with exchangeable synthetic arterial inlays were created to practice carotid endarterectomy and patch plasty, open abdominal aortic aneurysm surgery, and peripheral bypass surgery, as well as for endovascular procedures, including endovascular aneurysm repair, thoracic endovascular aortic repair, peripheral balloon dilatation, and stenting. All models are equipped with a small pressure pump inside to create pulsatile flow conditions with variable peak pressures of ~90 mm Hg. The VI course schedule consists of a series of 2-hour modules teaching different open or endovascular procedures step-by-step in a standardized fashion. Trainees practice in pairs with continuous supervision and intensive advice provided by highly experienced vascular surgical trainers (trainer-to-trainee ratio is 1:4). Several evaluations of these courses show that tutor-assisted training on lifelike models in an educational-centered and motivated environment is associated with a significant increase of general and specific vascular surgical technical competence within a short period of time. Future studies should evaluate whether these benefits positively influence the future learning curve of vascular surgical trainees and clarify to what extent sophisticated models are useful to assess the level of technical skills of vascular surgical residents at national or international board examinations. This article gives an overview of our experiences of >20 years of practical training of beginners and advanced vascular surgeons using lifelike pulsatile vascular surgical training models.

Expanded polytetrafluoroethylene graft for bypass surgery using the excimer laser-assisted nonocclusive anastomosis technique

OBJECT: Patients with complex craniocerebral pathophysiologies such as giant cerebral aneurysms, skull base tumors, and/or carotid artery occlusive disease are candidates for a revascularization procedure to augment or preserve cerebral blood flow. However, the brain is susceptible to ischemia, and therefore the excimer laser-assisted nonocclusive anastomosis (ELANA) technique has been developed to overcome temporary occlusion. Harvesting autologous vessels of reasonable quality, which is necessary for this technique, may at times be problematic or impossible due to the underlying systemic vascular disease. The use of artificial vessels is therefore an alternative graft for revascularization. Note, however, that it is unknown to what degree these grafts are subject to occlusion using the ELANA anastomosis technique. Therefore, the authors studied the ELANA technique in combination with an expanded polytetrafluoroethylene (ePTFE) graft. METHODS: The experimental surgeries involved bypassing the abdominal aorta in the rabbit. Ten rabbits were subjected to operations representing 20 ePTFE graft-ELANA end-to-side anastomoses. Intraoperative blood flow, followup angiograms, and long-term histological characteristics were assessed 75, 125, and 180 days postoperatively. Angiography results proved long-term patency of ePTFE grafts in all animals at all time points studied. Data from the histological analysis showed minimal intimal reaction at the anastomosis site up to 180 days postoperatively. Endothelialization of the ePTFE graft was progressive over time. CONCLUSIONS: The ELANA technique in combination with the ePTFE graft seems to have favorable attributes for end-to-side anastomoses and may be suitable for bypass procedures.

Membrane microdialysis: Evaluation of a new method to assess splanchnic tissue metabolism

OBJECTIVE: Measuring peritoneal lactate concentrations could be useful for detecting splanchnic hypoperfusion. The aims of this study were to evaluate the properties of a new membrane-based microdialyzer in vitro and to assess the ability of the dialyzer to detect a clinically relevant decrease in splanchnic blood flow in vivo. DESIGN: A membrane-based microdialyzer was first validated in vitro. The same device was tested afterward in a randomized, controlled animal experiment. SETTING: University experimental research laboratory. SUBJECTS: Twenty-four Landrace pigs of both genders. INTERVENTIONS: In vitro: Membrane microdialyzers were kept in warmed sodium lactate baths with lactate concentrations between 2 and 8 mmol/L for 10-120 mins, and microdialysis lactate concentrations were measured repeatedly (210 measurements). In vivo: An extracorporeal shunt with blood reservoir and roller pump was inserted between the proximal and distal abdominal aorta, and a microdialyzer was inserted intraperitoneally. In 12 animals, total splanchnic blood flow (measured by transit time ultrasound) was reduced by a median 43% (range, 13% to 72%) by activating the shunt; 12 animals served as controls. MEASUREMENTS AND MAIN RESULTS: In vitro: The fractional lactate recovery was 0.59 (0.32-0.83) after 60 mins and 0.82 (0.71-0.87) after 90 mins, with no further increase thereafter. At 60 and 90 mins, the fractional recovery was independent of the lactate concentration. In vivo: Abdominal blood flow reduction resulted in an increase in peritoneal microdialysis lactate concentration from 1.7 (0.3-3.8) mmol/L to 2.8 (1.3-6.2) mmol/L (p = .006). At the same time, mesenteric venous-arterial lactate gradient increased from 0.1 (-0.2-0.8) mmol/L to 0.3 (-0.3 -1.8) mmol/L (p = .032), and mesenteric venous-arterial Pco2 gradients increased from 12 (8-19) torr to 21 (11-54) torr (p = .005). CONCLUSIONS: Peritoneal membrane microdialysis provides a method for the assessment of splanchnic ischemia, with potential for clinical application.

Fenestrated and branched endografts: why we need them now

Standard endovascular repair of abdominal aortic aneurysm (AAA) has been shown to be associated with significant advantages compared with conventional surgery in the perioperative time frame related to the minimally invasive nature of the procedure. Given the encouraging long-term results of endovascular AAA repair, this method is increasingly applied to patients with complex AAA anatomies. The present article reviews the indications for branched and fenestrated endografts in various aortic pathologic processes.

Sixty-four-detector CT angiography of infrarenal aortic neck length and angulation: prospective analysis of interobserver variability

PURPOSE: To quantify the interobserver variability of abdominal aortic aneurysm (AAA) neck length and angulation measurements. MATERIALS AND METHODS: A total of 25 consecutive patients scheduled for endovascular AAA repair underwent follow-up 64-row computed tomographic (CT) angiography in 0.625-mm collimation. AAA neck length and angulation were determined by four blinded, independent readers. AAA neck length was defined as the longitudinal distance between the first transverse CT slice directly distal to the lowermost renal artery and the first transverse CT slice that showed at least a 15% larger outer aortic wall diameter versus the diameter measured directly below the lowermost renal artery. Infrarenal AAA neck angulation was defined as the true angle between the longitudinal axis of the proximal AAA neck and the longitudinal axis of the AAA lumen as analyzed on three-dimensional CT reconstructions. RESULTS: Mean deviation in aortic neck length determination was 32.3% and that in aortic neck angulation was 32.1%. Interobserver variability of aortic neck length and angulation measurements was considerable: in any reader combination, at least one measurement difference was outside the predefined limits of agreement. CONCLUSIONS: Assessment of the longitudinal extension and angulation of the infrarenal aortic neck is associated with substantial observer variability, even if measurement is carried out according to a standardized protocol. Further studies are mandatory to assess dedicated technical approaches to minimize variance in the determination of the longitudinal extension and angulation of the infrarenal aortic neck.

[Artificial intravascular oxygenation (IVOX). Application to the treatment of postoperative respiratory failure]

Very recently, the concept of artificial intracorporeal oxygenation of blood for patients suffering from respiratory failure has been introduced into clinical practice through development of a totally implantable intravascular oxygenator (IVOX). We report on the use of such a device in a patient who developed severe respiratory insufficiency secondary to prolonged hypovolaemic shock and pneumonia following successful repair of a ruptured abdominal aortic aneurysm in September, 1990. Postoperatively, severe hypoxaemia occurred (AaDO2 548-602 torr) despite extensive mechanical ventilatory support. There was no obvious chance to overcome this situation by conventional therapeutic measures and the decision was made to institute IVOX therapy. Hypoxaemia was resolved immediately and both FiO2 and tidal volume could be reduced within hours. The patient's respiratory condition continued to improve over the next days leading to termination of IVOX therapy after 71 hours. However, the necessity of long-term ventilatory support secondary to recurrent pneumonia and sepsis, multiple abdominal reoperations for ischemic colitis and retroperitoneal abscess prolonged his recovery. He was discharged from the hospital after four months and is alive and well now 14 months after his operation. He is the first long-term survivor after IVOX therapy in Europe. IVOX may be successfully used in selected patients while the indications and it's potential role in the therapy of severe respiratory failure still need to be defined.