Asclepiades – SurgeryPaedeia

Συντάχθηκε από:

Αναστάσιος Λιάτας, MD, F.I.C.A. – Διευθυντής Χειρουργός

A C Liatas, MD, F.I.C.A. – Consultant Surgeon

Athens  General  Hospital  » EVAGELISMOS «

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Introduction

The  development  of  the  IVC  involves  fusion,  regression, and establishment of midline anastomoses  between  parts  of three paired fetal venous systems: the two posterior cardinal veins,  the  two  subcardinal,  and  two supracardinal  νeins.  The  changes  in  the  abdominal venous  systems  that  produce  the  final  IVC  cover a long period from day 25 to day 50, mainly between days 29 and 41. Depending on the embryonic origin, four parts of the IVC have been recognized:  (1)  hepatic  segment,  (2)  prerenal segment,  (3)  renal  segment  and,  (4) postrenal segment. “Absent  IVC” normally designates absence of the prerenal segment of the IVC only, with azygos continuation being the most common variety of an interrupted IVC.  “Full IVC agenesis” should cover those cases in which all four parts of the IVC and the iliac venous system  are  absent  and blood return is accomplished by one or both of the following pathways: (1) vertebrolumbar pathway (anterior external vertebral plexus, ascending lumbar veins, and azygos  and  hemiazygos  veins), and  (2)  superficial  anterior  abdominal  wall collaterals. This definition  is  exemplified  by  the present  case  and  other  ones  previously reported. “Full IVC agenesis,” an extremely rare condition, may be compatible with normal adolescence, and such a congenital abnormality has never to our knowledge caused acute abdominal symptoms.

Absence of the entire inferior vena cava caused acute abdominal symptoms, and the patient, a twenty-year-old man, was operated on on an emergency basis. Subsequent ascending venography, abdominal computed tomographic scan, intraarterial digital subtraction angiography, and intra-osseous phlebography revealed full inferior vena cava and iliac venous system agenesis, up to and above the level of the hepatic veins, venous return from the lower limbs and the abdominal viscera being through a series of multiple collateral channels and the azygos-hemiazygos system.

Keywords

Inferior vena cava, full inferior vena cava agenesis, vena cava, agenesis of IVC, full agenesis of IVC, congenital anomalies of IVC, thrombosis of IVC

Discussion

There are at present no known therapeutic measures for this very  rare  anomaly.  In pure IVC  agenesis  disclosed  accidentally (eg, by chest x-ray), those cases revealed during investigation  of  patients  with  congenital  heart abnormalities, and those in symptomatic patients, the management should be focused on the prevention of complications, such as thromboses  in  the  distal drainage channels.

On the  other  hand, knowledge  of  this  condition  is important for surgeons to avoid ligation of the azygos vein in the  course  of pulmonary  or  cardiac  operation  because  prevention of the only  major  route  of  venous drainage  from  below  the  diaphragm may  result  in death. In complicated  cases, eg, hypertension due to a hypoplastic kidney, or ureteric obstruction from constricting venous  collaterals  as  in  the  present  case,  surgery is unavoidable. When thrombosis  occurs, a  life-threatening condition  for this type of patient, vigorous anticoagulant treatment  has  to  be  instituted  promptly  that  will last until sufficient venous return has been reestablished.

In  making  the  differential  diagnosis  the  following conditions should be taken into account:

1. Pathological mediastinal lesions and other vascular anomalies, when the IVC agenesis presents  as a mediastinal abnormality on the chest radiograph, to avoid mediastinoscopy  or  thoracotomy
2. Causes  of  dilatation  of  the  azygos-hemiazygos  venous system
3. The syndrome of obstruction of IVC in childhood
4. Abdominal wall venous collaterals and varicose veins because excision of these veins would interrupt a vital venous return or at least result in intractable ulcers
5. Retroperitoneal and para-aortic space-occupying structures
6. Causes of difficulty or prevention of catheterization of the heart from the IVC
7. Other causes of acute abdominal symptoms (although it should be last in the list)
8. Causes of ureteric obstruction
9. Causes of retroperitoneal hemorrhage
10. Causes of lower back pain
11. Causes of Klippel-Trenaunay syndrome

The  prognosis  of  this  rare  congenital  anomaly  seems to be directly related to the presence of  thrombosis  in  the retroperitoneal  venous collaterals and to any coexistent congenital anomalies  (cardiac  and  vascular  defects, situs  inversus). In  “full IVC agenesis”  thrombosis  is  the major cause of mortality and morbidity (paresthesias of lower legs and lower back pain  on  exertion,  retroperitoneal  hemorrhage,  hypertension,  ureteric  obstruction,  and  emotional  distress  due  to  dilated  superficial abdominal  wall veins).  Apart from this anomaly per se,  implicating  factors  favoring  thrombosis  in  this  category  of  patients have been reported such  as  (1)  oral  contraceptives  and  cigarette  smoking;  (2) increased intraabdominal pressure (constipation,  tumors,  pregnancy),  and  (3)  dehydration,  marasmus,  sepsis,  and  exertion. Therefore,  prevention  of  thrombosis  must  be  our  mainstay  in  helping  these patients.

Δημοσίευση Άρθρου

Το πλήρες άρθρο έχει δημοσιευτεί στο: [ Vascular Surgery, Vol. 27, No 2, March 1993; pp: 155-162 ]

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