Its 2:00 AM... Aortic Disasters. Case 1 (cont) Definitions.. Epidemiology. Diagnosis, Imaging Techniques and Management

Transcription

1 Aortic Disasters Diagnosis, Imaging Techniques and Management Eric R. Snoey, MD Alameda County Medical Center Oakland, CA Its 2:00 AM yo female presents with 4 hours of R flank pain, nausea and fatigue. In general, the patient states that she feels lousy. No amount of coaxing, coaching, cajoling or thinly veiled physical threats are successful in obtaining more information. ROS: no CP,SOB PmHX: NIDDM, smoking PE: Obese, anxious, uncomfortable VS: 150/80, 110, 16, 97.6 Chest/Card: normal Abd: no consistent pain, guarding or rebound Case 1 (cont) Differential: MI, PE, Chole, Renal stone, AAA, Mesenteric ischemia Laboratory, U/A, Chest X-ray, ECG = nl Insert image of ruptured AAA Becoming upset the patient says - You re stalling, you don t know what s going on - Definitions.. Aneurysm: localized dilatation of the entire vessel wall involving all three layers Dissection: hematoma within the arterial media causing a lengthwise separation Aortic Transection: traumatic tear of aorta usually at lig arteriosum Epidemiology Incidence: 2-4% of population over age 50 Avg age of dx 65 years, rare before age 50 Male >>> female 98% infra-renal Associated arteriosclerotic disease Smoking, HTN, Diabetes, family history, Normal Dimensions: 2.5 cm, or 1.5 Xs diameter at renals

2 Pressure wave effects Mural ischemia increased fibrosis, less elasticity Genetic predisposition Marfans, Erlos Danlos Pathophysiology Physical and hemodynamic factors Complications/Natural Hx All AAAs will rupture (if given time.) Retroperitoneal, Intraperitoneal, Into GI tract, Into IVC Thromboembolic Natural Hx (cont) Size(cm) Ruptured Unruptured Total %Ruptured <4 Enlargement 19 unpredictable % 4-5 yearly 15 rate varies 49 from cm to % cm Risk of rupture increases as aneurysm size % increases 7-10 There 26 is effective 37 no safe 68 size 45% > % Natural Hx (cont) Risk of rupture < 4.0 cm < 5% rupture at 5 years Early 4-5 cm Diagnosis 3-12% and rupture surgical at 5 years repair represents > 5 cm only means % rupture of at impacting 5 years survival statistics Elective surgical risk < 5%, Mortality if ruptured = >60% Presentation (un-ruptured) Most are asymptomatic... Symptoms: sensation of abdominal fullness, pulsations Signs: pulsatile, expansile abdominal mass abdominal bruit Thromboembolism blue toe syndrome, diminished pulses LE Presentation (ruptured) Classic Triad ( < than 30% of patients ) Back, Abdominal, Flank Pain Pulsatile abdominal Mass Hypotension May mimic many other disorders 24-42% misdiagnoses on 1st presentation (2X mortality rate)

3 Misdiagnoses Unusual Presentations GI Renal colic sepsis MVA Back pain MI Diverticulitis miscellaneou GI bleed Symptoms Chest pain Groin pain Syncope Bloody stool CHF Fistula Signs Absent classic triad (2/3 of cases) Thrombo-embolism T paraplegia (sacral sparing) Hematuria Diagnosis Physical Exam PE findings subtle and unreliable Palpable mass: Given the Overall: prevalence 68% (up sens, to 75% 4%) of specific AAA and high morbidity associated with misdiagnosis, the physical examination is inadequate to exclude the Sensitivity diagnosis = of 82% AAA if in AAA any > patient 5.0cm reasonably considered to be at risk. 53% if abdominal girth > 100cm Image patients at risk! Plain radiography 55% - 85% sensitive for AAA Curvilinear calcifications, loss of psoas/renal shadow, renal displacement Best view is lateral L/S spine Never use plain films to exclude AAA! - best indication: evaluation of!! alternative diagnoses Advantages Bedside, immediate, time efficient screening test (stable and unstable patients) 100% sensitive (if technically adequate) Look for alternative etiologies Ultrasound Disadvantages Obesity/bowel gas: obstacles to adequate study No information on if ruptured/complication

4 CT Highly sensitive and accurate Offers detailed info: rupture?, branch vessel involvement, mural thrombi (particularly with CTA, MSCT) May offer alternative diagnosis Disadvantage: Move to CT scanner, dye load and radiation Indication: stable symptomatic patient or unstable patient in!! whom the diagnosis remains in doubt Angiogram Less sensitive and accurate than either US or CT False negatives due to mural thrombi Costly, time consuming, invasive Case yo male presents with cough, fever and sore throat. PE: VSS Abd: prominent, pulsatile, mid abd mass, non tender Bed side US = AAA Management Asymptomatic patients AAA < 4 cm - require Q 6 month follow up - begin HTN therapy, stop smoking, add B-blocker - operate when 5.5 cm or becomes symptomatic AAA > 5.5 cm : most should undergo repair unless:! - risk of OR > observation (CHF, COPD, CVA)! - non AAA life expectancy < 2 years Management AAA cm: controversial zone Two studies (NEJM 5/2002), ~ 1700 patients with aneurysms cm randomized to immediate repair vs surveillance with repair only if: -Increase 0.7 cm in 6 months, -1.0 cm in one year, -Become symptomatic or -Reach 5.5 cm.

5 Management (cont) New or changing symptoms Hemodynamically stable, Symptomatic = Imminent if not acute rupture Results: no difference in survival, 30% fewer surgeries and hospitalizations in surveillance group Consider earlier surgery in women due to higher rupture risk ED management strategy Expedited diagnosis ( US vs Helical CT) Blood pressure control (B-blocker + Nipride vs Labetalol Prep for operative T&C, IV access, ECG, Surgical consultation Management (cont) Unstable patient... Operative Management IVF, T&C, Time to cross-clamp of aorta only controllable variable Delays lead to increased mortality Only reasonable diagnostic test is US Negative lap - 75% had serious abd abnormality requiring laparotomy Endovascular Grafts - less invasive - less expensive - shorter life span - best in higher surgical! risk patients -Many recent concerns about failure rates.. Another Case 32 yo male presents with sudden onset dysarthria and R hand numbness/weakness. Noted progressive shortness of breath over the past several hours. He denies chest pain. + History of hypertension and cocaine abuse - most recently today! PE: VS 110/40, 130, 24, 37, pulse ox = 98% Chest: clear Card: tachycardia,, II/IV diastolic murmur Neuro: Right facial and UE plegia

6 Aortic Dissection Classification (Stanford) Type A Aortic Dissection Type B Epidemiology ~ 0.5-1% of MI rate Long standing HTN (not atherosclerosis) Elastin and connective tissues disorders Marfan s, Cystic medial necrosis, Pregnancy, Cardiac Disorders Coarctation, Bicuspid aortic valve Trauma Acute stressors Cocaine/Met amphetamine Age-related Risk Factors associated with aortic dissection Risk factor Marfan syndrome AD > 40 y AD < 40 y 2% 49% P value <.001% Hypertension 74% 35% <.001% Bicuspid valve 3% 16% <.001% Prior aortic valve replacement 5% 13% <.01% 31% 2% <.001% Atherosclerosis 95% of Aortic Dissection occurs > 40 yo

7 Acute Aortic Syndrome Natural history Classical AD True and false lumen Longitudinal spread Intramural Hematoma Localized hematoma No Doppler flow/contrast on CT Penetrating Aortic Ulcer Typically descending aorta Rupture atherosclerotic plaques 20% 70% 10% 1-2%/hour mortality rate (untreated), 50% at 30 days Type A: Mortality 10% at 24 hours, 30% at 30 days Type B: Mortality 10% at 30 days if uncomplicated Haro et al. EM Clinics, Nov 2005 *International Registry of Aortic Dissection Presentation Pain +/- other symptoms: neurologic, limb ischemia, syncope, SOB (CHF, Pericardial Effus) Presentation Physical findings of AD present in < 50% of cases Pain Type Proximal Distal Signs Proximal Distal Chest anterior Chest Posterior Ant & Post Neck Abd 65% 10% 8% 8% 6% 27% 57% 16% 0% 4% Hypertension Hypotension Pulse Deficit 35% 12% 18% 70% 2% 9% Sharp Tearing/Ripping Migratory 64% 50% 16% 68% 52% 19% AI Murmur Neuro Deficit 44% 6% 12% 2% *International Registry of Aortic Dissection *International Registry of Aortic Dissection Mechanism of obstruction Method of pulse deficit and/or neuro sxs Diagnosis Clinical Suspicion/Appropriate patient type PLUS Sudden, atypical or migratory pain, tearing, mixed cardiovascular/neuro presentations Physical Exam: Excludes alternative diagnosis AI murmur, Pulse deficits Diagnosis can not be made without imaging study

8 Chest radiography CT 65% sensitive Widened knob Double wall sign Effusion or cap Wide mediastinum MRI TEE Advantages: accuracy, intimal tear localization, dx of AI and pericardial effusions Advantages: accurate, excellent anatomic detail Disadvantages: slow,unavailable, costly Disadvantages: requires sedation and cardiologist Serologic screening Smooth muscle myosin heavy chain (SMMHC) 90% sensitive in first 3 hours (IRAD patients), 44% sensitive later selaf : soluble elastin fragments. Sensitivity high if true and false lumen communicate, poor in setting of IMH Poor NPV D-dimer: 100% sensitive, 68% specific Small, retrospective study, High NPV but low specificity means many unnecessary imaging studies Shinohara et al, Arterio Throm Vasc, 2003, ** Weber et al. Chest May 2004, Katoh and Suzuki Circulation 2004 Control dp/dt Treatment Stop extension of dissection - ie contractility of the aorta Decrease blood pressure and decrease heart rate Target: lowest blood pressure that allows for normal mental status, SBP ~ Pain control Stabilization for surgery (Type A)

9 Drugs Goal is reduction of Force and Rate of contraction Variant mgt scenarios Drug Nipride Propranolol(Esmolol) Labetalol Trimethaphan Fenoldopam Blood press Contractility Dissection + Hypotension/CHF: Diff Dx AI: gentle rate control, early surgery Pericardial tamponade: IVF, early surgery (pericardiocentesis worse outcome..) MI: gentle rate control - early surgery, (avoid ASA, antithrombotics) Dissection + Neuro deficits Obstructive: gentle pressure and rate reduction (hold if neuro deficit widens), early surgery Surgery Noninvasive Endografts, Stents and Fenestration Reserved for most (80%)Type A and any (20%) Type B with vascular or neurologic complications Isolated Arch dissections medical Tx Uncomplicated Type B treated medically - B-blockers/anti-HTN vs endovascular grafts and stents