Sex disparities in popliteal artery aneurysms.

OBJECTIVE: Only 5% of patients with popliteal artery aneurysms (PAAs) are female. Evidence on PAA treatment and outcomes in women is therefore scarce. The POPART Registry provides one of Europe's largest data collections regarding PAA treatment. Data on clinical presentation, aneurysm morphology, and perioperative outcomes after open surgical PAA repair in women will be presented. METHODS: POPART is a multicenter, noninterventional registry for open and endovascular PAA repair, with 42 participating centers in Germany and Luxembourg. All patients aged >18 years who have been treated for PAA since 2010 are eligible for study inclusion. Data collection is based on an online electronic case report form. RESULTS: Of the 1236 PAAs, 58 (4.8%) were in women. There were no significant differences in age or cardiopulmonary comorbidities. However, female patients had a lower prevalence of contralateral PAAs and abdominal aortic aneurysms (P < .05). PAAs in women were more likely to be symptomatic before surgery (65.5% vs 49.4%; P = .017), with 19% of women presenting with acute limb ischemia (vs 11%; P = .067). Women had smaller aneurysm diameters than men (22.5 mm vs 27 mm; P = .004) and became symptomatic at smaller diameters (20 mm vs 26 mm; P = .002). Only 8.6% of women and 11.6% of men underwent endovascular aneurysm repair (P > .05); therefore, the perioperative outcome analysis focused on open surgical repair. In total, 23.5% of women and 16.9% of men developed perioperative complications (P > .05). There were no differences in major cardiovascular events (P > .05), but women showed a higher incidence of impaired wound healing (15.7% vs 7.2%; P = .05) and major amputation (5.9% vs 1.1%; P = .027). Female sex was significantly associated with the need for nonvascular reinterventions within 30 days after surgery (odds ratio: 2.48, 95% confidence interval: 1.26-4.88), whereas no significant differences in the odds for vascular reinterventions were observed (odds ratio: 1.98, 95% confidence interval: 0.68-5.77). In the multiple logistic regression model, female sex, symptomatic PAAs, poor quality of outflow vessels, and graft material other than vein graft were independently associated with perioperative reinterventions. CONCLUSIONS: Women have smaller PAAs, are more likely to be symptomatic before treatment, and are more often affected by nonvascular reinterventions in the perioperative course. As our understanding of aneurysmatic diseases in women continues to expand, sex-specific treatment strategies and screening options for women in well-selected cohorts with modified screening protocols should be continuously re-evaluated.

Real-world data of popliteal artery aneurysm treatment: Analysis of the POPART registry.

OBJECTIVE: Popliteal artery aneurysm (PAA) is a rare disease with a prevalence of 0.1% to 1%. Within previous years, endovascular repair (ER) of PAAs has been performed more frequently despite the lack of high-level evidence compared with open surgical repair (OSR). In 2014, the POPART registry was initiated to validate the current treatment options for PAA repair. METHODS: POPART is a multinational multicenter registry of the peri- and postoperative outcomes of ER and OSR for PAAs. Data sets were recorded using the online survey tool SurveyMonkey (available at: https://www.surveymonkey.com/). Regular monitoring and plausibility checks of the data sets are performed to ensure reliability. The aim of the present study was to report the findings from the POPART registry, which includes data from 41 centers. RESULTS: From June 2014 to August 2019, 794 cases had been recorded in the POPART registry. OSR had been performed in 662 patients and ER in 106 patients; 23 patients had been treated conservatively. Of the 106 patients in the primary ER group, 4 had required conversion to OSR. The ER patients were significantly older (ER, median, 71 years; OSR, median, 67 years; P < .05). No other significant differences were present in the demographic data, comorbidities, or aneurysm morphology between the two groups. Of the 662 patients in the OSR group, 50.3% were symptomatic compared with 29.2% of the 106 patients in the ER group (P < .05). Emergency treatment because of acute ischemia, critical ischemia, or rupture was necessary for 149 patients (22.5%) in the OSR group and 11 patients (10.3%) in the ER group. The most frequent postoperative complications were impaired wound healing (OSR, n = 47 [7.1%]; ER, n = 3 [2.8%]; P > .05) and major bleeding (OSR, n = 26 [3.9%]; ER, n = 3 [2.8%]; P > .05). The in-hospital length of stay was significantly longer for the OSR group than for the ER group (median, 10 days; range, 3-65 days; vs median, 7 days; range, 1-73 days). The overall patency for the OSR and ER groups after 12 and 24 months was 83.2% and 44.7% (P < .005) and 74.2% and 29.1% (P < .005), respectively. The outcomes with a prosthetic graft vs an autologous vein were significantly poorer in the OSR group (primary patency, 71.4% vs 88.1% at 12 months). CONCLUSIONS: To evaluate new treatment techniques such as ER for PAAs, real-world data are of essential importance. The present analysis of the first results for the POPART registry shows good perioperative results for endovascular treatment of PAA in asymptomatic patients with good outflow vessels. The perioperative complication rate is low and the postoperative hospital stay is shorter than after OSR. However, the patency rates after 12 and 24 months are low in the ER group compared to patients treated with open repair. More follow-up data is required for further interpretation; the completion of the data sets in the registry is ongoing.

The Prevention of Positioning Injuries During Gynecologic Surgery. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/077, October 2020).

Purpose Positioning injuries are relatively common, forensically highly relevant complications of gynecologic surgery. The aim of this official AWMF S2k-guideline is to provide statements and recommendations on how to prevent positioning injuries using the currently available literature. The literature was evaluated by an interdisciplinary group of experts from professional medical societies. The consensus on recommendations and statements was achieved in a structured consensus process. Method The current guideline is based on the expired S1-guideline, which was updated by a systematic search of the literature and a review of relevant publications issued between February 2014 and March 2019. Statements were compiled and voted on by a panel of experts. Recommendations The guideline provides general and specific recommendations on the prevention, diagnosis and treatment of positioning injuries.

Long-term graft outcome after renal arterial reconstruction during living related kidney transplantation.

BACKGROUND/OBJECTIVES: The aim of this retrospective study was to evaluate the repair of vascular variations/pathologies in living donor kidney transplantations in a single centre over a 15-year period. METHODS: Between 01/1997 and 05/2012, 338 living donor renal transplantations were performed in the Department for Endovascular and Vascular Surgery, University of Düsseldorf, Germany. Twenty-four of them showed disorders, like multiple renal arteries (MRA), atherosclerotic stenosis or fibromuscular dysplasia (FMD) needing vascular repair before transplantation. RESULTS: Mean age of donors was 51 ± 11.2, in recipient's 44 ± 13.9 years. In seven transplantations, renal artery (RA) repair was performed because of MRA. Atherosclerotic stenosis of the RA was apparent in 12 cases needing a repair with disobliteration. FMD was the reason in five transplantations for vascular repair. Complications like renal vessel thrombosis, lymphocele, heamorrhage, distal urinary leakage and ureteral obstruction was not significantly associated with RA reconstruction. Comparison of renal function in kidneys with reconstructed RA compared with kidneys without vascular repair showed no significant difference in primary function and serum creatinine up to the first year after transplantation. Mean follow-up was 75.6 ± 48.1 months. The 5-year graft survival rate for kidneys with RA repair was 88.5 vs. 93.4 % without reconstruction. CONCLUSIONS: We could show that RA pathologies, suitable repaired, are not a contraindication for transplantation with acceptable 5-year-graft-survival rates.

Results from the International Silver Graft Registry for high-risk patients treated with a metallic-silver impregnated vascular graft.

The purpose of this postmarket surveillance registry was to document the efficacy of a vascular prosthesis coated with metallic silver in high-risk patients undergoing vascular reconstructions. Patency (primary endpoint) and freedom from graft infection (secondary endpoint) data were assessed at a minimum of 12 months in patients with significant co-morbidity and/or confirmed graft infections or infected native vessels. Between November 2006 and December 2009, 230 patients with high-risk factors underwent aortic,peripheral and/or extra-anatomic reconstructions with Silver Graft® (SG) in six German, one French and one Polish vascular center.All participating centers used the metallic silver-coated polyester graft (SG) in various diameters and lengths including tubular and bifurcate vascular grafts. Doppler ultrasound follow-ups to determine graft patency were planned at 12 months or done at an earlier time in case the patient became symptomatic. A total of 230 patients were studied. Ten of these 230 patients had graft infections at baseline whereas the remaining 220 subjects had significant risk factors such as coronary artery disease (62.7%, 138/220), vascular access in scar tissue (27.3%, 60/220), Fontaine III/IV (38.2%, 84/220), chronic renal insufficiency (26.8%, 59/220) and diabetes (21.0%,46/220). The long-term follow-up at 15.5 ± 8.3 months revealed a secondary patency rate of 93.2% (205/220) and an 'all cause' mortality rate of 18.6% (41/220). There was a freedom from de novo graft infection rate of 95.9% (211/220) in the high-risk group without graft infections at baseline. One regraft infection occurred distal of the revisional reconstruction in the 10 patients with graft infection at baseline. The presence of perigraft fluid at follow-up and Fontaine III/IV at baseline were found to be predictors for graft patency whereas perigraft fluid presence was the only predictor for de novo graft infections. This registry revealed favorable patency and freedom from de novo infections rates in a 'high-risk' population with significant co-morbidities.

Time is brain?--Surgical revascularization of acute symptomatic occlusion of the internal carotid artery up to one week.

BACKGROUND: Clinical outcome and surgical success rate of open surgical reconstruction for acute symptomatic internal carotid artery (ICA) occlusion up to 1 week after stroke onset were analyzed to determine a cutoff time, after which risk exceeds clinical benefit. METHODS: From November 1997 to March 2007, a total of 5369 patients were examined at the authors' stroke unit; 502 from this cohort underwent ICA reconstruction. A subgroup of 49 patients underwent surgical revascularization of acute ICA occlusion within 168 hr at a mean of 42.5±38.7 hr after stroke onset. Preoperative diagnostic measures consisted of extracranial/intracranial duplex sonography (n=49), cerebral computed tomography (n=31), magnetic resonance imaging and angiography (n=37), and digital subtraction angiography (n=24). All 49 patients experienced a complete ICA occlusion and an ipsilateral recent ischemic infarction. Modified Rankin scale score (mRS) before surgery was 0 to 3 in 20 patients (41%) and 4 to 5 in 29 patients (49%). RESULTS: ICA patency could be restored in 38 patients (78%). The following clinical outcomes were noted: clinical improvement in mRS by at least 1 point in 23 of 49 of patients (47%), no change in 14 of 49 (28%), deterioration in mRS by at least 1 point in 6 of 49 (12%), and death within 30 days in 6 of 49 (12%). A total of 21 patients (43%) experienced perioperative cerebral events (new infarction, new intracranial hemorrhage or enlargement, or hemorrhagic transformation of the preexisting infarction). Univariate analysis showed that clinical improvement correlated significantly with success of recanalization and with early recanalization within 72 hr. Age, gender, and preoperative Rankin stage did not have influence. Clinical deterioration or death was only associated with perioperative cerebral events and seemed to be time-independent. Multivariate analysis did not have enough statistical power to analyze the impact of different risk factors on outcome after urgent revascularization. CONCLUSIONS: In patients who undergo surgery after 72 hr from symptom onset, the risk seems to outweigh the benefit.

Renal artery revascularization after unsuccessful percutaneous therapy: a single centre experience.

PURPOSE: This retrospective review describes the long time effect of surgical revascularization after unsuccessful early or mid-term failure of percutaneous transluminal renal angioplasty (PTRA). METHODS: From January 1995 to January 2005, 60 out of 696 patients operated due to renal artery occlusive disease (17 fibromuscular dyplasia (FMD): mean age, 33.4 years; 43 atherosclerotic disease (ASD): mean age, 62.46 years) after unsuccessful PTRA underwent surgical revascularization for renal artery stenosis at our institution. The mean duration from failed PTRA to operation was 1.74 years. Out of the 68 renal arteries, 44 were pretreated with angioplasty alone (19, FMD; 25, ASD), and 24 were treated with PTRA and stent (all ASD). Operative management, response of renal function and hypertension as well as survival were compared to the literature. RESULTS: Fifty-nine per cent (n = 40) of the renal arteries were treated by transaortic thrombendarterectomy, 37% (n = 25) by bypass. Thirty-day and in-hospital mortality was 0% in all pretreated patients; after a mean of 4.16 years, it was 16.6% (only atherosclerotic). There was a significant decrease in systolic blood pressure values for all patients early after surgery as well as in follow-up. Creatinine remained stable in the patients with FMD, and there was an insignificant increase in creatinine level in the atherosclerotic patients. Hypertension was improved or healed in 32.5% of all pretreated patients, in cases with FMD in 54%, in atherosclerotic cases in 22.2%. Re-stenoses occurred in 26% of cases with FMD and in 18% of patients with atherosclerotic RAS. CONCLUSION: Surgical renal artery revascularization after failed PTRA is feasible and safe and systolic blood pressure can be lowered. The higher rate in re-stenoses in both the literature as well as in our own experience may be explained by the alterations in the renal artery after interventional treatment.

Critical chronic peripheral arterial disease: does outcome justify crural or pedal bypass surgery in patients with advanced age or with comorbidities?

BACKGROUND: We wanted to know the effect of comorbidity, age, and gender on the outcome after surgical below-knee revascularization for critical chronic limb ischemia. METHODS: This is a retrospective study of 624 consecutive patients who underwent below-knee bypass surgery between January 1996 and December 2005 because of chronic peripheral arterial disease (PAD). Patients' characteristics were: diabetes mellitus (DM) n = 445 (71%), coronary artery disease (CAD) n = 310 (49%), dialysis-dependent renal insufficiency (dRI) n = 88 (14%), age >70 years n = 279 (44%), male n = 423 (68%), PAD Fontaine's stage III n = 105 (17%), and PAD stage 4 n =519 (83%). All patients had Trans Atlantic Inter-Society Consensus (TASC) C and D lesions, all were treated with a vein bypass to a crural artery n = 354 (57%) and to a pedal artery n = 270 (43%). Kaplan-Meier analysis and multivariate analysis were performed. RESULTS: The early results were as follows. The 30-day major amputation rate was n = 43 (7%). CAD, dRI, age, and gender did not influence major amputation rate, whereas patients with diabetes had a lower risk of early amputation than those without diabetes. (hazard ratio: 0.49, 95% confidence interval: 0.25-0.95, p < 0.05). The 30-day mortality rate was n = 31 (5%) and was uninfluenced by DM, CAD, and gender. Patients with dRI and octogenarians had a high risk of early death (dRI: 13.6%, octogenarians 9.4%). The late results were as follows. Follow-up rates were: limb salvage n = 596 (95.5%) and survival n = 622 (99.7%). The limb salvage rates at 1, 3, and 5 years were 79.1%, 72.1%, and 66.4%, respectively, and were uninfluenced by DM, CAD, dRI, age, and gender. The mortality rates at 1-, 3-, and 5-years were 79%, 63.4%, and 47.3%, respectively. Comorbidities such as CAD, dRI, and age of >70 years reduced life expectancy significantly. DM did not influence 1, 3 and 5 years of survival. The 5-year survival rates as estimated by Kaplan-Meier analysis after revascularization were: DM, 46%; CAD, 38%; dRI, 19%; and age >70 years, 37%. CONCLUSION: Advanced age and comorbidities reduce life span but not the chance of avoiding major amputation after below-knee bypass surgery for critical limb ischemia.

Visceral artery aneurysms--follow-up of 23 patients with 31 aneurysms after surgical or interventional therapy.

PURPOSE: Visceral artery aneurysms (VAA) are rare forms of vascular pathology, with an incidence of 0.1% to 0.2% in routine autopsies. They frequently present as a life-threatening, often fatal, emergency, if associated with rupture and intra- or retroperitoneal bleeding. The clinical symptoms, natural history, and mortality of VAAs vary depending on the vessels involved. The mortality rates range from 8.5% up to 25% and, in pregnant women, up to 75%. A retrospective analysis of all VAAs diagnosed at our institution from 1991 to 2006 was performed. The presentation, management, and outcome of therapy was evaluated for each patient. MATERIALS AND METHODS: Twenty-three patients (12 men, 11 women, mean age 55.8 years) with 31 VAAs were identified. The anatomical involvement concerned seven regions: celiac (CT) nine, superior mesenteric (SMA) seven, splenic (SA) five, hepatic (HA) six, gastroduodenal (GDA) two, pancreatoduodenal (PDA) one, and one branch of the superior mesenteric artery. Fourteen patients presented symptoms attributable to their aneurysms, which included a total of four ruptures. Nine patients had no symptoms. The etiology of VAAs was atherosclerosis (67.8%), mycotic embolization (12.9%), trauma (9.7%), Marfan Syndrome (3.2%), Klippel-Trenaunay-Weber syndrome (3.2%), and giant cell arteritis (3.2%). Open surgery was performed for 29 aneurysm in 21 patients: partial resection and tailoring in 13 cases (41.9%), resection of the aneurysm with additional autologous vein graft interposition in nine cases and prosthetic graft interposition in 2 cases (35.5%), aneurysm exclusion by ligation in three cases (9.6%) and aneurysm ligation combined with additional autologous bypass procedure in two cases (6.5%). Two patients (6.5%) were treated interventionally with embolization, in one case each with a right hepatic artery aneurysm and in the other with splenic artery aneurysm. RESULTS: No deaths were observed. The morbidity rate associated with surgical treatment was low. After treatment, a total of 17 patients were followed up for a period ranging from 3 to 154 months (mean 54.6 months). Fifteen patients required no additional procedures. The patency rate of the reconstructed visceral arteries was 90.4%. Six patients were lost for follow-up. CONCLUSIONS: Surgical and interventional therapy of VAAs can be life-saving treatments for the patient with a low periprocedural morbidity. The success rate, defined as the exclusion of VAA rupture and the absence of abdominal discomfort, in our material was 88.2% after a mean follow-up of 54.6 months.

Prospective randomized trial of operative vs interventional treatment for renal artery ostial occlusive disease (RAOOD).

INTRODUCTION AND OBJECTIVES: Patients with either renovascular hypertension (RVH) and/or renal insufficiency (RI) due to renal artery ostial occlusive disease (RAOOD) can successfully undergo an open surgical reconstruction procedure (OSRP), but since the publication of Blum et al(1) percutaneous balloon stent angioplasty (PTRA + stent) leaving a small part of the stent within the aorta has become very popular. However, balloon dilatation and stenting does not remove the atherosclerotic plaque, which is often heavily calcified but leads to disruption of the plaque causing myointimal hyperplasia and recurrent stenosis. Therefore, a comparison of the two treatment modalities concerning complications and durability in a prospective randomized design was felt to bring more insight to the discussion. METHODS: From 1998 to 2004, we performed OSRP in 330 patients with RVH and/or RI for various locations of RAOOD. During this time period, 50 patients (female 18, male 32, mean age 64.4 years) with RAOOD of at least 70% stenosis (DSA and duplex criteria) in one or both renal arteries, who did not require other aorto/mesenteric/iliac reconstructive procedures agreed and were randomized to either OSRP (n = 25 patients, 49 arteries) or PTRA + stent (n = 25 patients, 28 arteries). Two patients crossed over to surgical treatment. Patients were followed on a regular basis for 4 years and longer. Endpoints were re-occurrence of RAOOD and impairment of either kidney function or RVH. RESULTS: We approached 77 arteries. There was no early mortality in either group, but directly procedure-related morbidity was 13% in the interventional group and 4% in the surgical group. Four-year follow-up mortality was 18% in the interventional group and 25% in the surgical group. Both groups showed significant improvement of RVH (P < .001 in each group) as well as improvement or stabilization in patients with insufficient renal function. Freedom from recurrent RAOOD (>70%) was achieved in 90.1% of the surgical group and 79.9% of the interventional group. CONCLUSION: Both treatment modalities showed good early results concerning RVH, kidney function, and renal perfusion. Despite a higher number of bilateral renal artery reconstructions in patients undergoing OSRP, which was probably due to the preferred technique of transaortic endarterectomy eliminating the plaque originating in the aorta and usually extending into both renal arteries, mortality was not higher and procedure-related morbidity was even lower compared to PTRA + stent. These findings and also longer durability of OSRP imply that surgical reconstruction remains the gold standard for patients with RAOOD before PTRA + stent may be considered.

Extracranial carotid arteries aneurysms in children: single-center experiences in 4 patients and review of the literature.

BACKGROUND: Extracranial carotid artery aneurysms (ECAAs) are very rare conditions in children but carry a great potential of thromboembolic episodes and ruptures. METHODS: To determine the clinical and therapeutic characteristics of ECAA in children in our department, we reviewed the patients' records and completed the data from phone correspondence, written survey, and clinical examination. RESULTS: From January 1981 to June 2006, 4 patients younger than 18 years were surgically treated for ECAA in our department. They were 3 boys and 1 girl. A medical history of tonsillectomy was reported in 3 patients. The aneurysm was symptomatic in all of the patients, local signs being present in every patient. The aneurysm caused hemispheric symptoms in 1 patient and finally stroke. The aneurysms were located in the common carotid artery, in the external carotid artery, and 2 in the internal carotid artery. The cause was congenital, mycotic, and traumatic (post tonsillectomy); for 1 patient, the etiology remained unknown. Aneurysm resection and interposition with vein graft were performed in 3 patients. The external carotid artery aneurysm was resected without reconstruction. There was no perioperative death or stroke. During the early follow-up period, 1 patient had a transient dysphagia and another a transient facial palsy. The patient with preoperative stroke remained with a neurologic deficit. All these patients were followed since the operation. The patient operated on in 1981 is asymptomatic after 25 years, but the graft became occluded 3 years after the operation. The patient who had recurrent attacks is still with residual neurologic deficit. The 2 other patients are without complains; the reconstructions remain patent. CONCLUSION: Although very rare, ECAA can be encountered even in the pediatric population. The past medical history may reveal a tonsillectomy, although the relation may not be easy to establish. Local signs may be accompanied by hemispheric thromboembolic complications, rupture, and bleeding. Therefore, surgical treatment is indicated, but can be challenging according to the anatomical location of the aneurysm.

Kidney transplantation from related and unrelated living donors in a single German centre.

BACKGROUND: Organ transplantation began in 1954 with living related donation (LRD). Because of organ shortage from cadavers, unrelated kidney donation (LURD) has been proposed and shown to have good results despite complete HLA mismatching. This study aims to look at differences and similarities comparing LRD and LURD performed in our centre since the implementation of the German transplant law in 1997. METHODS: Between January 1997 and July 2001, 62 out of 112 potential living donors and their recipients were accepted. Immunosuppression consisted of triple therapy (steroids, cyclosporin, mycophenolate) in patients with three or fewer mismatches, or quadruple therapy including mono- or polyclonal antibody treatment in patients with four or more mismatches or cytotoxic antibodies. LRD and LURD groups were compared for number and type of rejections, complications and kidney function at the end of observation (median 15.5 months, range 1-50 months). RESULTS: Out of 112 pairs presenting, transplantation was performed in only 62 cases (55.4%). Reasons to deny transplantation were medical problems of the potential donors in 19, psychological problems in 13, recipient problems in seven and other reasons in 11 pairs. In 38 cases LRD transplantation and in 24 cases LURD transplantation was carried out. Recipient age was significantly lower in the LRD group (37.7+/-12.1 years) compared with the LURD group (53.6+/-7.8 years). Mean donor age was 49.7+/-9.2 years in the LRD group and 50.3+/-9.1 years in the LURD group (ns). The number of mismatches was lower in LRD (2.1+/-1) than in LURD (4.4+/-0.9) (P=0.001) transplantation. The acute rejection rate was similar in both groups (52.2 vs 54.2%). OKT3 and tacrolimus rescue therapy for more severe rejections was more often applied in the LRD group but the difference did not reach the level of significance. There were more infectious complications in LURD transplantation (66.7 vs 36.4%, P=0.036) and a trend towards more surgical complications in LRD transplantation (28.9 vs 8.3%, P=0.062). One graft was lost due to transplant artery thrombosis and one recipient died 4 months after transplantation subsequent to cerebral ischaemia. Both patients belonged to the LRD group. Creatinine values at the end of observation time were 1.76+/-0.6 mg/dl in the LRD group and 1.62+/-0.5 mg/dl in the LURD group (ns). CONCLUSION: Although kidney transplantation from unrelated donors was performed with a lower HLA match and although the recipients were older, the results are equivalent to living related transplantation. Therefore, kidney transplantation from emotionally related living donors represents a valuable option for patients with end-stage renal disease. Careful selection of donors and recipients is a prerequisite of success.

Spontaneous rupture of collateral venous aneurysm in a patient with agenesis of the inferior vena cava: a case report.

We present a case of rupture of collateral venous vessels in the presence of agenesis of the inferior vena cava in a young woman. The embryologic development, pitfalls in diagnosis, and options for treatment in cases with agenesis of the inferior vena cava are discussed.