Ruptured aortic aneurysms

1. RUPTURED ANEURYSMS OF THE AORTA VAISHNAVI SURESH NAIR

2. The  aorta  is the main trunk of a series of vessels which convey the oxygenated blood to the tissues of the body for their nutrition. It commences at the upper part of the left ventricle, where it is about 3 cm in diameter, and after ascending for a short distance, arches backward and to the left side, over the root of the left lung . It then descends within the thorax on the left side of the vertebral column, passes into the abdominal cavity through the aortic hiatus in the diaphragm, and ends, considerably diminished in size (about 1.75 cm. in diameter), opposite the lower border of the fourth lumbar vertebra, by dividing into the right and left common iliac arteries. Branches: The  ascending aorta,  the  arch of the aorta,  and the  descending aorta, which is again divided into the  thoracic   and   abdominal aorta. THE AORTA

3. THE AORTIC VALVE The aortic valve, or aortic semilunar valve, has three leaflets or cusps. It is located at the base of the aorta. It opens to allow blood to leave the left ventricle as it contracts. When the ventricular muscles relax, the valve closes to prevent blood from backing up into the ventricular chamber.

4. ASCENDING AORTA (Aorta Ascendens)   The  ascending aorta  is about 5 cm. in length. It commences at the upper part of the base of the left ventricle, on a level with the lower border of the third costal cartilage behind the left half of the sternum; it passes obliquely upward, forward, and to the right, in the direction of the heart’s axis, as high as the upper border of the second right costal cartilage, describing a slight curve in its course, and being situated, about 6 cm. behind the posterior surface of the sternum. At its origin it presents, opposite the segments of the aortic valve, three small dilatations called the  aortic sinuses.   At the union of the ascending aorta with the aortic arch the caliber of the vessel is increased, owing to a bulging of its right wall. This dilatation is termed the  bulb of the aorta,  and on transverse section presents a somewhat oval figure. The ascending aorta is contained within the pericardium, and is enclosed in a tube of the serous pericardium, common to it and the pulmonary artery Branches: The only branches of the ascending aorta are the two coronary arteries ( Right & Left) which supply the heart; they arise near the commencement of the aorta immediately above the attached margins of the semilunar valves.

5. ARCH OF AORTA ( A rcus aorta/transverse aorta) The arch of the aorta is the second major anatomical region of the aorta; it curves above the heart between the ascending and descending aorta. All of the blood delivered from the heart to the systemic tissues of the body passes through the aorta, making it the largest artery in the human body. As the aorta extends from the heart, it begins as the ascending aorta before turning 180 degrees towards the body’s left side in the aortic arch. From the arch the aorta passes posterior to the heart and descends through the thorax and abdomen as the descending aorta . Branches: Three major arteries branch off from the superior arterial wall of the aortic arch to supply blood to the tissues of the superior regions of the body: the brachiocephalic trunk, left common carotid artery, and left subclavian artery . The brachiocephalic trunk is the first artery to arise from the aortic arch, carrying blood to the right arm and the right side of the head and neck. Next to branch from the aorta is the left common carotid artery that supplies blood to the left side of the head and neck. Finally, the left subclavian artery arises from the aortic arch and supplies blood to the left arm.

6. DESCENDING AORTA Although the descending aorta is positioned to the left of the body's midline, it gradually descends to directly in front of the vertebral column at the left of the 12th thoracic vertebra. The portion of the descending aorta above the diaphragm is called the thoracic aorta , and gives off branches into the thoracic wall. B ranches of thoracic aorta: T he Bronchial arteries, Mediastinal arteries, Esophageal arteries, Pericardial arteries, Superior phrenic arteries & supply blood to the organs for which they were named. Below the diaphragm, the descending aorta become the abdominal aorta and stems off into branches that reach the abdominal wall and various tissues and organs of the abdomen.

7. Branches of abdominal aorta:

8. Epidemiology Ruptured abdominal aortic aneurysms (AAAs) cause 12,000 deaths per year, 8,000 of these are infra-renal. Women are much less frequently affected . Ruptured abdominal aortic aneurysm ( AAA ) is one of the most   fatal surgical emergencies, with an overall mortality rate of   90 %. Rupture of a thoracic aneurysm has a greater than 97% fatality rate. Risk factors The presence of an aneurysm is a risk for rupture . The larger the lesion , the more likely it is to bleed ; aneurysms over 6 cm have a 25% annual risk of rupture. Smoking and hypertension  are additional risks . A ruptured aneurysm should be considered whenever a man aged over 55 or a woman aged over 70 presents with circulatory collapse .

9. PATHOPHYSIOLOGY Aorta consists of 3 layers- Intima, Media & Adventitia. Certain diseases causes weakening of the aortic walls , reduces its elasticity. When blood is pumped through these weakened areas, it bulges out, which are called aneurysms. As the flow and thus the pressure through this area increases, it causes the rupture of the aneurysm of the aortic wall.

10. Clinical Presentation A ruptured aneurysm usually presents with pain. Ruptured Thoracic aortic aneurysm (RTAA) It will cause   chest pain   , Ripping sensation in chest , Severe back pain , between shoulder blades Haemoptysis (erodes to trachea), Hematemesis (erodes into esophagus )   can occur . Dizziness, Hypotension, Syncope Difficulty in walking or speaking If bleeding occurs into the mediastinum , it can cause cardiac tamponade   and rapidly be fatal . The patient will probably never reach hospital alive and the diagnosis is made post-mortem.

11. Ruptured Abdominal aortic aneurysm (RAAA) Ruptured AAA presents with a classical triad of pain in the flank or back,  hypotension   and a pulsatile abdominal mass ; however, only about half have the full triad. Tachycardia develops. S hock may occur. The patient will complain of the pain and may feel cold, sweaty and faint on standing . The following symptoms are listed with approximate frequency of presentation Abdominal pain (60%) Back pain (70%) Syncope (30%) Vomiting (20%)

12. RUPTURED ABDOMINAL AORTIC ANEURYSM

13. RUPTURED ABDOMINAL AORTIC ANEURYSM Abdominal aortic aneurysm (AAA ) - sites of rupture and   their incidence Intraperitoneal rupture (20%) Retroperitoneal   rupture (80%) Aortocaval fistula (3–4 %) Primary aortoduodenal   fistula (<1 %) Rarely, Into the abdominal veins or the bowel.

14. Pressure builds within aneurysm Rupture of aortic aneurysm Normal abdominal aorta Aneurysm

15. Anterior intraperitoneal rupture A tear in the anterior wall of the aneurysm results in   sudden severe abdominal or back pain and collapse. The resultant   bleeding into the peritoneal cavity is so rapid that exsanguination   and death usually occur before the patient reaches the hospital .   Posterior retroperitoneal rupture Classical clinical picture Rupture into the retroperitoneal cavity is the most common site of ruptured AAA . A tear in the posterolateral aneurysm   wall leads to retroperitoneal bleeding which manifests clinically   as back pain with or without abdominal pain and hypotension . This tear is often sealed for a few hours , which allows time   for the transfer of the patient to the hospital, diagnosis,   and treatment. On examination, a pulsatile epigastric mass   is often palpable , particularly in a thin patient . But   this mass may not be palpable in obese or distended patients   or in those with severe hypovolaemia.

16. Unusual presentations of ruptured abdominal aortic aneurysm The temporary sealing of the tear in the aneurysm wall may rarely   extend beyond a few hours. This results in a variety of misleading   symptoms and signs because of the extension of the retroperitoneal   haematoma and its compressive effects. In ruptured   AAA the duration of symptoms may be unusually long,  and that   an abdominal pulsatile mass may be absent.   Transient   lower limb paralysis Right hypochondrial pain Nephro ureterolithiasis Groin pain Testicular pain Testicular ecchymosis   (blue scrotum sign of Bryant) Iliofemoral venous thrombosis Inguinoscrotal   mass mimicking a hernia

17. The three most frequent emergency presentations of ruptured   AAA and their immediate management are : A patient known to have an AAA presents with a sudden onset   of abdominal or back pain and hypotension   A patient presents   with the classical triad of pain, hypotension,   and a pulsatile   mass.   In the two previous scenarios, a haemodynamically unstable patient   should be immediately transferred to the operating theatre for   emergency open repair. Recently, endovascular aneurysm repair   (EVAR) has been successfully used to treat ruptured AAA. In   hospitals with capabilities for EVAR, a haemodynamically stable   patient can undergo a preoperative computed tomography (CT)   scan, and if the anatomy of the aneurysm is suitable, the patient   can undergo endovascular repair for his/her ruptured aneurysm. A patient is suspected of having a ruptured AAA, regardless   of the symptoms and signs, and is haemodynamically stable .   This patient should undergo a CT scan to confirm the diagnosis   and assess his/her suitability for EVAR . Emergency presentations of ruptured   AAA

18. Chronic contained rupture of AAA Although most patients with ruptured AAA have an acute presentation,   some patients may escape detection for weeks or months after   the aneurysm ruptures . This usually occurs when a retroperitoneal   rupture leads to slow progressive bleeding which forms a large   haematoma that is contained by the resistance of the periaortic   tissues. Approximately 4% of ruptured AAA are contained ruptures   .  They are also known as " sealed " or " spontaneously   healed " aneurysms . Most patients with   a contained rupture are haemodynamically stable with no manifestations   of acute blood loss . But a contained rupture is a ruptured aneurysm in a   stable patient that may progress to free rupture at any time . Thus , urgent surgical treatment within 24 h , preferably after   admission to an intensive care unit, is necessary.   Most patients with a contained rupture present with chronic   back pain that may radiate to the groin . Other reported presentations includes lumbar vertebral   erosion, lumbar spondylitis-like symptoms, left   lower limb weakness or neuropathy, crural neuropathy,   left psoas muscle haematoma, and obstructive jaundice . Rupture into the abdominal veins Rarely, AAA ruptures into the inferior vena cava or the left   renal vein. This results in an aortocaval fistula or an aorta–left   renal vein fistula , respectively.

19. Aortocaval fistula A spontaneous aortocaval fistula most commonly occurs when an   AAA erodes (ruptures) into the inferior vena cava Approximately   3–4% of patients with ruptured AAA have an aortocaval   fistula.  In these patients, the manifestations of rupture usually dominate the clinical picture and significantly diminish   the chance of preoperative diagnosis.  Aortocaval   fistulae are probably missed in 50% of patients and are discovered   accidentally during elective repair of AAA.  Trauma and surgery   of the lumbar spine are other known causes of aortocaval fistulae . The manifestations of an aortocaval fistula are variable because   they depend on the size of the communication between the aorta   and the inferior vena cava. Thus, temporary or permanent closure   of this communication by an aortic mural thrombus or by a compressing   aneurysm will change the clinical picture.

20. The discovery of an aortocaval fistula during surgery is associated   with major blood loss and the possibility of pulmonary embolization   with thrombus material from the aneurysm sac. Thus, unless   the patient presents in extremis due to the rupture, every effort   should be made to detect the fistula preoperatively.   Abdominal CT scan is the definitive imaging test for the evaluation   of AAA, and all patients suspected of having an aortocaval fistula   should undergo a contrast CT whenever possible. Characteristic   CT findings are loss of the fat plane between the aorta and   inferior vena cava, vena caval effacement, and direct inflow   of contrast from the aorta to the inferior vena cava. Clinically, a patient   with an aortocaval fistula presents with a classical triad of   abdominal or back pain, a pulsatile abdominal mass, and a continuous   bruit on abdominal auscultation.  This triad is reported   in 50–90% of patients. Patients with   an aortocaval fistula may also present with manifestations of   high output heart failure such as dyspnoea, tachycardia, wide   pulse pressure, cyanosis, and lower limb oedema.   Additional symptoms and signs include angina, palpitations   hypotension, fever, oliguria, haematuria, pulsatile   peripheral veins, and diminished lower limb pulses.

21. Aorta–left renal vein fistula   It most commonly occurs when the   wall of an infrarenal AAA erodes into the left renal vein. The   left renal vein normally crosses in front of the abdominal aorta   on its way to the inferior vena cava. In 1–2.4% of people,   however, the vein crosses behind the aorta.  A retro aortic   left renal vein is involved in more than 90% of cases of aorta–left   renal vein fistula . The " abdominal pain, haematuria, silent left kidney " syndrome   described by Mansour  et al summarises the clinical features   of aorta–left renal vein fistula. Haematuria is the most   important clinical feature in this condition, followed   by pain which is usually felt in the left flank and radiates   to the groin, mimicking ureteric colic. A pulsatile abdominal   mass and a left sided continuous bruit are detected in approximately   60% and 70% of patients, respectively.  Renal dysfunction is   usually seen in 85% of patients.  High output heart failure, similar to   that seen in an aortocaval fistula, can also be seen in patients   with an aorta–left renal vein fistula. The degree of heart   failure depends mostly on the size of the fistula.  Although   extremely rare, an aorta–left renal vein fistula should   be ruled out if a patient with an AAA develops haematuria, left   loin pain, or manifestations of renal dysfunction .

22. A contrast   CT scan of the aorta can visualise the fistula, which should   be looked for if a retro aortic left renal vein is seen.   Preoperative diagnosis can avoid unnecessary blood loss when   the aneurysm is opened during surgery. Intra operatively , a palpable   thrill over the aneurysm , or an absent left renal vein anterior   to the aorta , should raise suspicion of an aorta–left   renal vein fistula.  An extremely rare cause of haematuria   is an aortoureteric fistula. Here, the communication is usually   between the ureter and a previously inserted aortic graft, but   it can also occur with an aortoiliac aneurysm.  The triad of   unilateral hydronephrosis, intermittent haematuria, and previous   aortic surgery should alert the clinician to this life threatening   but potentially curable disease.

23. Rupture into the bowel ( aorto enteric fistula) An aorto enteric fistula is an abnormal communication between   the abdominal aorta and the bowel; it may be primary or secondary .   A primary aorto enteric fistula connects an infra renal AAA to   the bowel, most commonly the duodenum ( aortoduodenal fistula).   This condition is often fatal but fortunately rare, with an   estimated incidence at autopsy of 0.04–0.07 %.  A secondary aorto enteric fistula is a late postoperative complication due   to erosion of a prosthetic aortic graft into the duodenum . This   condition is more common, occurring in 0.5–2.3% of patients   after aortic surgery.  The third and fourth parts of the duodenum   are most commonly involved in an aorto enteric fistula because   this duodenal segment is closely applied to the anterior wall   of the aorta, being fixed posteriorly by the ligament of Treitz.   However, communications with other parts of the gastrointestinal   tract have also been reported. Patients with a primary aortoduodenal fistula commonly present   with upper gastrointestinal haemorrhage (hematemesis, melena,   haematochezia).   Abdominal pain and a pulsatile abdominal mass   may also be present; however, patients rarely have all three   findings . Gastrointestinal   haemorrhage was the most common presentation in patients with   primary aortoduodenal fistula, occurring in 96% of patients.   Massive haemorrhage is uncommon initially; patients usually   experience an episode of small brisk bleeding which stops spontaneously.   This "herald bleed" is characteristic of an aortoduodenal fistula

24. Oesophagogastroduodenoscopy (OGD) is likely to be the first   diagnostic test done in patients with upper gastrointestinal   haemorrhage, even if the cause of the bleeding is an aortoduodenal fistula.  OGD is useful to rule out the much more common causes   of bleeding such as gastroduodenal ulcers and oesophageal varices.   If bleeding is due to an aortoduodenal fistula, OGD may not   be precise in visualising the fistula because of failure to   pass the endoscope into the third or fourth parts of the duodenum.   Consequently , in patients with known or previously treated AAA   presenting with unexplained upper gastrointestinal haemorrhage,   CT has emerged as the most important initial diagnostic test   to rule out an aortoduodenal fistula. Highly suggestive   findings on CT include loss of the fat plane between the aorta   and duodenum and the presence of air in the retroperitoneal   cavity.  Unless a primary gastrointestinal source of bleeding   has been unequivocally identified in a bleeding patient with   AAA, an aortoduodenal fistula should always be ruled out. Currently ,   the preoperative diagnosis of aortoduodenal fistulae is reached   in only 50% of patients.

25. RUPTURED AAA IN CHILDREN Aortic aneurysms are extremely rare in children, and their aetiology   is different from those in adults. In children, aortic wall   infection, vasculitis , and connective tissue disorders are important causative factors for AAA. Umbilical vein catheterisation   is also a well recognised cause of childhood AAA, possibly through   infection. Most AAAs in children present as painless pulsatile masses; But a few alarming cases of rupture have   been reported. Ruptured AAA is not often suspected in   children; But its fatal & should   immediately rule out ruptured AAA in children if it is suspected.

26. Physical Examination A patient with a ruptured aneurysm at any level is likely to look pale and unwell and to be cold and sweaty. The pulse will be rapid, weak and thready. Hypotension is common. With a ruptured AAA there may well be a pulsatile mass in the vicinity of the bifurcation of the aorta. This is a few centimetres above the umbilicus and a little to the left. It may be tender and a bruit may be audible. Bleeding causes peritoneal irritation and it may appear as an acute abdomen. The following findings are listed with approximate frequency : Palpable mass (90%). Tenderness (80%). Systolic blood pressure (BP) below 80 mm Hg (40%). NB: presentation can be atypical, eg: intestinal obstruction from haematoma or an apparent irreducible inguinal hernia. Rare presentations are : Severe hematemesis from an aorto - duodenal fistula. A fistula into the inferior vena cava, producing lower limb oedema and high-output cardiac failure.

27. Differential diagnosis The differential diagnosis for a ruptured TAA is that of chest pain, especially MI with cardiogenic shock   but also massive pulmonary embolism. The differential diagnosis for ruptured AAA involves other causes of abdominal pain, including acute abdomen . Investigations If an aneurysm is ruptured, investigations need to be swift and pertinent. Laboratory studies C BC : NB: if there has not been time for haemodilution then haemoglobin will be normal. Anaemia is present in less than half of patients. Around 80% have a white cell count of 10 x 10 9 /L or more . CMP Group and rapid cross-match : whilst arranging surgery . Baseline biochemistry of U&Es : should be performed.

28. Radiology CXR : for a TAA the CXR may well show an enlarged base of aorta . Plain abdominal X-ray : for an AAA this will show the lesion in about 75%, as it is often calcified . Portable ultrasound : this examination may be helpful but there is not time for detailed assessment. If there is strong suspicion of a ruptured aneurysm then immediate surgery may be the investigation of choice . Other investigations : CT angiography will confirm the diagnosis. MRI and angiography are an alternative but, practically, more time-consuming so probably only suitable for the stable patient. ECG ECG : is important In patients presenting with chest pain.

29. TREATMENT Abdominal aortic aneurysms (AAAs) are typically repaired by an operative intervention . The possible approaches are the traditional open laparotomy , newer minimally invasive methodologies, or by the placement of endovascular stents . INDICATIONS: Open repair: Diameter of the aneurysm greater than 2 inches Abdominal Pain Abdominal Pulsation Endovascular repair: S evere Heart diseases Age risks Other underlying medical conditions

30. PRE-OPERATIVE MEASURES Type and cross match blood IV line (fluids, antibiotics, anesthesia) Administer prophylactic antibiotics (cefazolin, 1 g intravenous piggyback ) Insert a Foley catheter Monitor central venous pressure or establish Swan- Ganz catheterization (if indicated ) Prepare the skin from the nipples to the mid thigh Administer general anesthesia (open), general/regional anesthesia (endovascular) Insert a nasogastric tube

31. Open repair of an abdominal aortic aneurysm involves an incision of the abdomen to directly visualize the aortic aneurysm. The procedure is performed in an operating room under general anaesthesia. The surgeon will make an incision in the abdomen either lengthwise from below the breastbone to just below the navel or across the abdomen and down the centre. Once the abdomen is opened, the aneurysm will be repaired by the use of a long cylinder-like tube called a graft. Grafts are made of various materials, such as Dacron (textile polyester synthetic graft) or polytetrafluoroethylene (PTFE, a non textile synthetic graft). The graft is sutured to the aorta connecting one end of the aorta at the site of the aneurysm to the other end of the aorta. 4-6hrs duration 5-10 days hospital stay Open repair

32. Endo Vascular Aneurysm Repair (EVAR) EVAR is a minimally-invasive (without a large abdominal incision) procedure performed to repair an abdominal aortic aneurysm. EVAR may be performed in an operating room, radiology department, or a catheterization laboratory. Surgeon may use general anesthesia or regional anesthesia (epidural or spinal anesthesia). The surgeon will make a small incision in each groin to visualize the femoral arteries in each leg. With the use of special endovascular instruments, along with X-ray images for guidance, a stent-graft will be inserted through the femoral artery and advanced up into the aorta to the site of the aneurysm. A stent-graft is a long cylinder-like tube made of a thin metal framework (stent), while the graft portion is made of various materials such as Dacron or polytetrafluoroethylene (PTFE) and may cover the stent. The stent helps to hold the graft in place. The stent-graft is inserted into the aorta in a collapsed position and placed at the aneurysm site. Once in place, the stent-graft will be expanded (in a spring-like fashion), attaching to the wall of the aorta to support the wall of the aorta. The aneurysm will eventually shrink down onto the stent-graft . 2-3hrs duration 2-3 days hospital stay

33. Postoperative Details Fluid shifts are common following aortic surgery. Fluid requirements may be high in the first 12 hours, depending on the amount of blood loss and fluid resuscitation in the operating room. Monitor the patient in the surgical intensive care unit for hemodynamic stability, bleeding, urine output, and peripheral pulses. A postoperative electrocardiogram and chest radiograph are needed. Prophylactic antibiotics ( eg, cefazolin at 1 g) are administered for 24 hours. The patient is seen in 1-2 weeks for suture or skin staple removal, then yearly thereafter.

34. Complications of the procedure Open repair Myocardial infarction (heart attack ) Irregular heart rhythms (arrhythmias) Bleeding during or after surgery Injury to the bowel ( intestines) Limb ischemia (loss of blood flow to legs/ feet) Embolus (clot) to other parts of the body Infection of the graft Lung problems Kidney damage Spinal cord injury EVAR Damage to surrounding blood vessels, organs, or other structures by instruments Kidney damage Limb ischemia (loss of blood flow to leg/feet) from clots Groin wound infection Groin hematoma (large blood-filled bruise) Bleeding Endo leak (continual leaking of blood out of the graft and into the aneurysm sac with potential rupture) Spinal cord injury

35. Prognosis No more than 1 in 3 patients with a ruptured aortic aneurysm will reach hospital alive, and 20% of those who do, fail to reach theatre . Delay in diagnosis is a major risk factor. Elective repair of AAA has a mortality of around 5% compared with 60-80% for emergency repair. The following factors are associated with a mortality rate in excess of 80 %: Age over 80 . Presentation in shock with free intraperitoneal rupture. Failure of BP to rise, despite attempts at resuscitation. Haematocrit below 25% on admission. Preoperative  cardiac arrest.

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