Aortic Dissection


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Aortic Dissection

  1. 1. Aortic Dissection Zahir Rahman MD 10/14/02
  2. 2. ED History – 9:55 A.M. <ul><li>46 y.o AA male with with no pmhx cc: of weakness lower extremities and inability to walk. Pt said 6 to 7 hours prior to arrival, he had sudden onset interscapular and abdominal pain which progressed to weakness. </li></ul><ul><li>Neurosurgery called by ED staff for acute onset paraplegia. </li></ul>
  3. 3. Neurosurgery PE – 10:30 AM <ul><li>VS: 122/70 P: 72 RR: 14 </li></ul><ul><li>Muscle Strength: 2/5 L foot, all other LE muscle strength 0/5 </li></ul><ul><li>Sensory level below T5, diminished but can feel light touch </li></ul><ul><li>Rectal Sphincter Tone: </li></ul>
  4. 4. Neurosurgery A/P <ul><li>W/u for aortic aneurysm/ dissection </li></ul><ul><li>R/o Spinal Cord compression </li></ul><ul><li>Continue Solumedrol, send for MRA. </li></ul>
  5. 5. MRA <ul><li>Pt. had MRA done at 11:30 A.M. </li></ul><ul><li>CICU resident called with result at 12:30 A.M. </li></ul><ul><li>Patient was found to have a Type 1 Aortic Dissection. No Pericardial effusion. No Aortic Regurgitation </li></ul><ul><li>Dissection from Proximal Aorta to below the Renal arteries. </li></ul><ul><li>False Lumen was communicating with the Left Renal Artery. </li></ul>
  9. 10. CV Fellow Called: 12:30 P.M. <ul><li>46 y.o AA male from Liberia – No PMHx woke up at 3 AM with sudden onset 10/10 Anterior Chest Pain (Pressure like) and interscapular pain with radiation down both arms. Over the course of the next 6-7 hours, he developed diffuse abdominal pain, followed by numbness from chest to feet which progressed to bilateral weakness at which point he called for an Ambulance. </li></ul>
  10. 11. <ul><li>12:40 P.M. – pt complaining of CP 5/10 and abdominal pain, but no longer has sensory or motor weakness of lower extremities. </li></ul><ul><li>PMHx: Pt says he has seen a doctor here and there and his bp was always fine. </li></ul><ul><li>SHx: denies cocaine/drug use </li></ul><ul><li>Exsmoker – quit 1 year ago. 10 pack year history </li></ul><ul><li>FHx: No h/o sudden cardiac deaths. Mother and Father with HTN. </li></ul>
  11. 12. PE <ul><li>Vs: BP: R arm: 150/90 L arm: 154/90 </li></ul><ul><li>Neck: No JVD, No Bruits </li></ul><ul><li>Lungs: CTA b/l </li></ul><ul><li>CV: RRR, S1,S2 nl, + S4, no murmurs </li></ul><ul><li>ABD: Diffuse tenderness, no rebound, normal BS. </li></ul><ul><li>EXT: Pulses equal and symmetric B/L </li></ul><ul><li>NEURO: No defecits, DTRs’ normal b/l </li></ul>
  12. 13. Labs: 7/30/02 9:35 AM <ul><li>Bun/Cr: 29/2 </li></ul><ul><li>AST: 41 </li></ul><ul><li>ALT: 39 </li></ul><ul><li>AP: 70 </li></ul><ul><li>CK: 257 </li></ul><ul><li>MB: 2.4 </li></ul><ul><li>Trop: 0.3 </li></ul>
  13. 14. EKG
  14. 15. Management <ul><li>Pt was immediately bolused with esmolol and titrated gradually to a bp of approximately 122/70. </li></ul><ul><li>Pt was transferred for surgery at 1:20 PM to SIUH </li></ul>
  15. 16. Intraoperative TEE Ascend Aorta
  16. 17. Intraoperative TEE – Aortic Arch
  17. 18. Descend Aorta – Communication back into true lumen
  18. 19. Descend Aorta – Multiple Intimal Flaps
  19. 20. Intraoperative TEE <ul><li>NO AI, NO Effusion </li></ul><ul><li>Proximal Dissection – Not involving sinus of valsalva </li></ul><ul><li>Concentric LVH </li></ul><ul><li>Multiple Dissection Flaps in Ascending and Descending Aorta </li></ul>
  20. 21. Surgery <ul><li>Dissected Ascending Aorta was dissected and replaced with a #22 mm Dacron interposition graft with a circumferential bypass </li></ul><ul><li>Pt. was hemodynamically stable post surgery. </li></ul><ul><li>Troponin at 21:51 - 1.28 (cutoff 0.5 for AMI) </li></ul>
  21. 22. Course: <ul><li>Labs: </li></ul><ul><li>7/31: CK: 666 / 3563 </li></ul><ul><li>7/31: Troponin: 4.5 </li></ul><ul><li>7/31: MB: 25/ 27.9 </li></ul>
  22. 23. Hospital Course <ul><li>Pt. was in ICU and became septic, ARF progressed to ESRD, Acute Liver Failure, developed mesenteric ischemia </li></ul><ul><li>Pt. was managed with pressors (Levophed) and was made DNR by family. </li></ul><ul><li>On 8/10: CT scan showed large pericardial effusion and dissecting aneurysm of the thoracic aorta. </li></ul><ul><ul><ul><li>Bun/Cr: 155/12.1 </li></ul></ul></ul><ul><ul><ul><li>AST/ALT: 2360/1500 </li></ul></ul></ul><ul><ul><ul><li>Patient coded, went into EMD and died. </li></ul></ul></ul>
  23. 24. Aortic Dissection Zahir Rahman MD 10/14/02
  24. 25. Classifications <ul><li>Acute: when diagnosis is made within 2 weeks of initial onset of symptoms </li></ul><ul><li>Chronic: >2 weeks of symptoms </li></ul><ul><li>One third of patients fall into the chronic category. </li></ul>
  25. 26. Common Classification Systems Braunwald
  26. 27. Common Classifications of Aortic Dissection
  27. 28. Variants of Aortic Dissection
  28. 29. Predisposing Factors <ul><li>Men/Female Ratio 2:1 to 5:1 </li></ul><ul><li>Chronic Systemic HTN (62-78%) </li></ul><ul><li>Proximal Dissection: </li></ul><ul><ul><li>Peak age 50-55 years </li></ul></ul><ul><ul><li>MC on initial presentation to have HTN 70% </li></ul></ul><ul><li>Distal Dissection: </li></ul><ul><ul><li>Peak Age 60-70 years </li></ul></ul><ul><li>Direct Iatrogenic Trauma: 5% of cases </li></ul><ul><li>Indirect Trauma (eg sudden deceleration) </li></ul>
  29. 30. Predisposing Factors <ul><li>Hereditary Connective Tissue Diseases </li></ul><ul><ul><li>Marfan Syndrome </li></ul></ul><ul><ul><li>Ehler Danlos Syndrome </li></ul></ul><ul><li>Chromosomal Aberrations </li></ul><ul><ul><li>Turners Syndrome </li></ul></ul><ul><ul><li>Noonans Syndrome </li></ul></ul><ul><li>Aortic Diseases </li></ul><ul><ul><li>Aortic Dilatation </li></ul></ul><ul><ul><li>Aortic Aneurysm </li></ul></ul><ul><ul><li>Anuloaortic ectasia </li></ul></ul><ul><ul><li>Aortic Arteritis </li></ul></ul><ul><ul><li>Bicuspid Aortic Valve </li></ul></ul>
  30. 31. Predisposing Factors <ul><li>Females in 3 rd Trimester Pregnancy or 1 st Stage of Labor </li></ul><ul><li>Case Reports of: </li></ul><ul><ul><li>Cocaine (Perron et al. Am J Emerg Med 1992) </li></ul></ul><ul><ul><li>Abrupt Discontinuation of Beta Blockers (Eber et al. Cardiology 1993; 83:128-131) </li></ul></ul><ul><ul><li>Probably Secondary to rapid rise in first derivative of pressure (dp/dt) on aortic wall. </li></ul></ul>
  31. 32. Cystic Medial Degeneration <ul><li>Medial Degeneration predisposes dissection by decreasing cohesiveness of layers of aortic wall </li></ul><ul><ul><li>More extensive in patients with: </li></ul></ul><ul><ul><ul><li>HTN </li></ul></ul></ul><ul><ul><ul><li>Marfan Syndrome </li></ul></ul></ul><ul><ul><ul><li>Bicuspid Aortic Valves </li></ul></ul></ul><ul><ul><li>But, even in other causes of dissection, medial degeneration is much greater than expected with normal aging. </li></ul></ul>
  32. 33. Pathogenesis <ul><li>Intimal tears occur in regions of aorta subjected to greatest dp/dt and pressure fluctuations. </li></ul><ul><li>MC sites for initiation of intimal tear: </li></ul><ul><ul><li>Ascending Aorta </li></ul></ul><ul><ul><li>1 st Portion Descending Aorta </li></ul></ul>
  33. 34. Proposed Mechanism of Initiation of Dissection
  34. 35. Natural History <ul><li>Hydrodynamic forces propagate the dissection until rupture occurs either: </li></ul><ul><ul><li>Back into the lumen of the aorta </li></ul></ul><ul><ul><li>Through the adventitia (causing death) </li></ul></ul><ul><li>Mortality Rates if untreated: </li></ul><ul><ul><li>1-3% per hour </li></ul></ul><ul><ul><li>90% within 3 months </li></ul></ul><ul><li>Death usually caused by: </li></ul><ul><ul><li>Acute aortic regurgitation </li></ul></ul><ul><ul><li>Major branch vessel obstruction </li></ul></ul><ul><ul><li>Aortic Rupture ( into pericardium, L pleural cavity, or mediastinum) </li></ul></ul>
  35. 36. Symptoms of Aortic Dissection According to a report on 464 patients from the International Registry of Acute Aortic Dissection. (Hagan et al. Jama 2000; 283:897-903)
  36. 37. Clues to Proximal Dissection <ul><li>Substernal chest pain </li></ul><ul><li>Neck, jaw, throat or face pain </li></ul><ul><li>Aortic Insufficiency </li></ul><ul><li>Decreased pulse or blood pressure in R arm </li></ul><ul><li>Decreased R carotid pulse </li></ul><ul><li>Pulse abnormalities are seen in 50% of proximal dissections </li></ul><ul><li>Ischemic EKG changes </li></ul><ul><li>AMI – Inferior (5%) </li></ul><ul><li>Marfans Syndrome </li></ul><ul><li>Hypotension </li></ul><ul><li>Syncope – 12% </li></ul><ul><li>CVA – 5-10% </li></ul>
  37. 38. Aortic Regurgitation <ul><li>AR in 18-50% cases </li></ul><ul><li>Diastolic murmur reported in 25% pts. </li></ul><ul><li>Acute Severe AR – 2 nd MC cause of death AD. </li></ul><ul><li>Murmur can wax and wane and intensity will vary with BP </li></ul><ul><li>3 possible mechanisms for acute AR in dissection </li></ul>Hagan et al. IRAD. JAMA 2000;283:897-903.
  38. 39. Mechanisms of Aortic Regurgitation in Proximal AD
  39. 40. Hypotension with Proximal Dissection <ul><li>Cardiac tamponade </li></ul><ul><li>Severe acute Aortic regurgitation with cardiogenic shock </li></ul><ul><li>Myocardial Infarction with resultant LV systolic dysfunction – usually RCA. </li></ul><ul><li>Acute Aortic Rupture. </li></ul><ul><li>Pseudohypotension by involving brachiocephalic artery </li></ul>
  40. 41. Predicting Death in Type A Aortic Dissection (Mehta et al. Circulation. 2002;105:200-206) <ul><li>Evaluated 547 patients enrolled in IRAD from Jan 1996 to Dec 1999. </li></ul><ul><li>In hospital mortality was 32.5%, 26.9% in surgically treated patients vs. 56.2% in medically treated patients </li></ul><ul><li>Rupture accounted for 33.3% of deaths </li></ul><ul><li>Neurological defecit - 13.9 % of deaths </li></ul><ul><li>Visceral ischemia/kidney failure (11.5%) </li></ul><ul><li>Cardiac Tamponade (7.9%) </li></ul>
  41. 42. Clinical Variables Associated with High In-Hospital Mortality Rates. (Mehta et al. Circulation. 2002;105:200-206)
  42. 43. <ul><li>Interscapular pain </li></ul><ul><li>HTN less commonly associated about 35% </li></ul><ul><li>Left Pleural effusion </li></ul><ul><li>Pulse defecits are less frequent about 15% </li></ul><ul><li>Usually involve femoral or left subclavian </li></ul><ul><li>Spinal Cord Ischemia (10%) </li></ul><ul><ul><li>Transverse Myelitis </li></ul></ul><ul><ul><li>Paraplegia </li></ul></ul><ul><ul><li>Quadriplegia </li></ul></ul>Clues to Distal Dissection
  43. 44. Clinical Prediction of Acute Aortic Dissection (von Kodolitsch et al, Arch Intern Med 2000;160:2977-2982) <ul><li>Jan 1 1988 to Dec 31, 1996 41,495 presented to ED at Univ Hosp Eppendorf, Hamburg, Germany. </li></ul><ul><li>250 constituted study group </li></ul><ul><ul><li>CP, back pain or both within last 2 weeks </li></ul></ul><ul><ul><li>ACS or another diagnosis excluded </li></ul></ul><ul><ul><li>Of remaining patients, considered if suspicious for AD by 2 ED physicians. </li></ul></ul><ul><li>26 Clinical Variables to find any independent clinical predictors of dissection. </li></ul>
  44. 45. (von Kodolitsch et al, Arch Intern Med 2000;160:2977-2982)
  45. 46. (von Kodolitsch et al, Arch Intern Med 2000;160:2977-2982)
  46. 47. <ul><li>Aortic Pain: immediate onset, tearing or ripping character or both. </li></ul><ul><li>Mediastinal Widening </li></ul><ul><li>Pulse Differentials </li></ul>(von Kodolitsch et al, Arch Intern Med 2000;160:2977-2982)
  47. 48. EKG <ul><li>EKG: 1/3 exhibit LVH </li></ul><ul><li>EKG is important to rule out any ischemic changes or MI which would lead to an alternate diagnosis </li></ul><ul><li>EKG may display infarction </li></ul><ul><li>EKG – usually shows nonspecific ST-T wave changes. </li></ul>
  48. 49. CXR <ul><li>Widened Mediastinum suggestive but not diagnostic. </li></ul><ul><li>Seen Anywhere from 50% in most reports. </li></ul><ul><li>And in one report of 236 cases as high as: 90% (Spittell, Mayo Clinic Proc 68:642,1993.) </li></ul>
  49. 50. Normal Aorta in CXR 3 years Prior
  50. 51. Enlargement of the Aortic Knob A Case of Proximal Aortic Dissection
  51. 52. Comparison of Imaging Modalities (Braunwald)
  52. 53. Aortography <ul><li>Sensitivity: 86-88% </li></ul><ul><li>Specificity: 75-94% </li></ul><ul><li>False negatives if intramural hematoma or thrombosis of false lumen </li></ul><ul><li>Good at detecting branch vessel involvement and Coronary Artery invovlvement. </li></ul>
  53. 54. Thoracic Aortagram in AP view
  54. 55. CT <ul><li>Sensitivity 83-94% </li></ul><ul><li>Specificity of 100% </li></ul><ul><li>Spiral CT increased sensitivity to 96% </li></ul><ul><li>Non-invasive with rapid availability (MC initial imaging modality in IRAD pts) </li></ul><ul><li>Needs contrast to be effective </li></ul><ul><li>Disadvantages: </li></ul><ul><ul><li>Cannot Detect AR </li></ul></ul><ul><ul><li>Does not detect Site of Intimal Tear well </li></ul></ul><ul><ul><li>Cannot detect Coronary Artery Involvement </li></ul></ul>
  55. 56. Contrast-Enhanced CT at level of Ventricle
  56. 57. Left Anterior Oblique View Contrast Enhanced CT Intimal Flap originates beyond Left SC Artery
  57. 58. TEE <ul><li>Non-Invasive, Performed Quickly at Bedside </li></ul><ul><li>Sensitivity 98 – 99% </li></ul><ul><li>Specificity: 94 – 95% (biplane or multiplane TEE) </li></ul><ul><li>Good at detecting Coronary Artery Involvement </li></ul><ul><li>Disadvantage: does not evaluate distal ascending aorta and proximal arch (because of the interposition of air filled trachea and main stem bronchus) </li></ul>
  58. 59. Descend Aorta – Communication back into true lumen
  59. 60. MRI <ul><li>Gold Standard for Diagnosis </li></ul><ul><li>Sensitivity and Specificity of 98-100% </li></ul><ul><li>Disadvantages: </li></ul><ul><ul><li>Limited Availability </li></ul></ul><ul><ul><li>Limit the presences of monitoring and support devices </li></ul></ul><ul><ul><li>Relatively CI in unstable patients. </li></ul></ul><ul><ul><li>CI: </li></ul></ul><ul><ul><ul><li>Pacemakers </li></ul></ul></ul><ul><ul><ul><li>Certain types of vascular clips </li></ul></ul></ul><ul><ul><ul><li>Older metallic heart valves </li></ul></ul></ul>
  61. 62. Practical Assessment of Imaging Modalities
  62. 63. Smooth Muscle Myosin Heavy Chain <ul><li>AD causes extensive damage to the smooth muscle cells of the media releasing smooth muscle heavy chain into the circulation. </li></ul><ul><li>Serum Values: </li></ul><ul><ul><li>95 AD pts: 22.4 +/- 40.4 ug/L </li></ul></ul><ul><ul><li>131 Volunteers: 0.9 +/- 0.4 ug/L </li></ul></ul><ul><ul><li>48 AMI pts: 2.1 +/- 1.6 ug/L </li></ul></ul><ul><ul><li>33 pts presented within 3 hrs of onset of AD: 51+/-52.3 ug/L </li></ul></ul><ul><li>Serum Levels > 10 ug/L showed 100% specificity for Aortic Dissection. </li></ul>(Suzuki et al. Circulation 1996;93:1244-1249)
  63. 64. MANAGEMENT <ul><li>Therapy is targeted at halting the progression of the dissection </li></ul><ul><li>It is the course of the tear not the tear itself that leads to compromise of vasculature or rupture </li></ul><ul><li>Goal: </li></ul><ul><ul><li>Reduction of SBP (100-120) </li></ul></ul><ul><ul><li>Dimunition of dp/dt (reflects force of LV ejection) through use of a beta blocker. </li></ul></ul>
  64. 65. Sodium Nitroprusside <ul><li>Sodium Nitroprusside for acute reduction starting 10 – 20 mcg/min and titrated upward </li></ul><ul><li>Must initiate BB prior to instituion of Nipride due to its effect on raising dP/dT when used alone </li></ul><ul><li>Adding IV BB prior until desired effect such as HR 60 – 80s (propranolol 1 mg Q 3-5 minutes max 10 mg) </li></ul><ul><li>Then Q 4-6 hrs at a dose of 2 – 6 mg </li></ul>
  65. 66. Labetolol <ul><li>Effectively lowers dP/dT as well as reducing arterial pressure </li></ul><ul><li>Initial dose is 20mg followed by 40 to 80 mg Q 10 – 15 minutes (max 300mg IV) </li></ul><ul><li>Once BP controlled maintenance by continuous infusion </li></ul><ul><li>Infusion at 2mg/min titrating up to 5 –10 mg/min </li></ul>
  66. 67. Esmolol <ul><li>Ultra short acting BB for those with labile blood pressure or those that are surgical candidates. (Long acting medications may affect intraoperative bp management) </li></ul><ul><li>Load with 500 mcg/kg bolus </li></ul><ul><li>Infusion starts @ 50mcg/kg/min titrate to 200 mcg/kg/min for control </li></ul><ul><li>Controls dP/dT as well as blood pressure </li></ul><ul><li>Can be used in patients with uncertain risk for bronchospasm </li></ul>
  67. 68. Contraindications to BB <ul><li>Patients with severe Brady or AV block or bronchospasm BB may be CI </li></ul><ul><li>Calcium channel blockers specifically Cardizem and Diltiazem can be used if bronchospasm </li></ul><ul><li>Provide negative Inotrope and Chronotropic effects </li></ul><ul><li>If Dissection involves the renal arteries patients may develop high renin HTN </li></ul><ul><li>Treat with IV enalapril </li></ul>
  68. 69. Other Considerations <ul><li>Hypotension must ensure if its true or false </li></ul><ul><li>May be secondary to compromise of artery by dissection (pseudohypotension) so check both arms </li></ul><ul><li>If true hypotension may indicate rupture or tamponade </li></ul><ul><li>Fluids first then use levophed (norepinephrine) or phenylephrine (neosynephrine) </li></ul><ul><li>Dopamine should be avoided since it can raise dP/dT unless used at low doses for renal perfusion </li></ul>
  69. 70. Cardiac Tamponade <ul><li>Pericardiocentesis may be harmful </li></ul><ul><li>Retrospective study of 7 patients (6 hypotensive, 1 normotensive) </li></ul><ul><ul><li>3 of 4 with successful Pericardiocentesis died w/in 5-40 minutes of the procedure due to acute EMD </li></ul></ul><ul><ul><li>0 of 3 w/o pericardiocentesis died prior to surgery </li></ul></ul>Isselbacher et al, Circulation 1994: 90;2375-2378.
  70. 71. Cardiac Tamponade <ul><li>Increase in Intraaortic pressure after pericardiocentesis causing a reopening of the closed communication between the false lumen and pericardial space, leading to lethal cardiac tamponade. </li></ul><ul><li>Prudent to do Pericardiocentesis in AD only if in EMD or marked hypotension, and aspirate only enough pericardial fluid to raise bp. </li></ul>
  71. 72. Indications for Definitive Surgical and Medical Therapy in AD
  72. 73. Surgical Repair of Proximal Dissections
  73. 74. Surgery <ul><li>Preop mortality 3% if expedited and increases to 20% if prolonged </li></ul><ul><li>Objectives of surgery are to remove the most severely damaged segments of the aorta and to obliterate the false lumen by suturing the most proximal segment </li></ul><ul><li>Long term survival is not effected by failure to resect intimal tear (Miller et al. Journal Thoracic CV Surg 78:365;1979. </li></ul>
  74. 75. Surgery with AR <ul><li>In certain cases valve can be preserved by removing tear and resuspending leaflets </li></ul><ul><li>It avoids long term anticogulation </li></ul><ul><li>However if repair is unsuccessful or if patient had pre-existing valvular disease need AVR </li></ul><ul><li>In patients with Marfans need AVR </li></ul>
  75. 76. Endovascular techniques <ul><li>For treating high risk patients ( i.e. renal or visceral involvement) which carry a high operative mortality (>50%) </li></ul><ul><li>Balloon fenestration flow back to true lumen decompressing false lumen </li></ul><ul><li>Stenting of branch vessels compromised by dissection. </li></ul><ul><li>Intraluminal stent – grafts to close off the site of entry into false lumen and promote thrombosis. </li></ul><ul><li>30 Day mortality for Proximal Dissections of intraluminal stents reported around 25%. </li></ul><ul><li>At present, about 13% of patients with AD get endovascular stenting. </li></ul>
  76. 77. Long Term <ul><li>Survival in PAD s/p repair who survive their hospital stay is: </li></ul><ul><ul><li>65-80% at 5 years </li></ul></ul><ul><ul><li>50% at 10 years </li></ul></ul><ul><li>MC cause of death in long-term survivors: </li></ul><ul><ul><li>Rupture of the Aorta due to subsequent dissection or aneurysm formation. </li></ul></ul><ul><li>Long Term Management: </li></ul><ul><ul><li>Optimal BP control with Beta blockers </li></ul></ul><ul><ul><li>Periodic clinical and imaging assessments of Aorta </li></ul></ul>
  77. 78. Intramural Hematoma (H)
  78. 79. Crescenteric Hematoma that does not Enhance confirming a intramural Hematoma that does not communicate with the Aortic Lumen.
  79. 80. Evolution of a Penetrating atherosclerotic Ulcer of Aorta