Previous exam 1999 Flashcards
Signs and symptoms of myxoma
Constitutional signs a. fatigue b. fever c. arthralgias d. weight loss e. clubbing f. anemia g. malaise h. thrombocytopenia TIA/CAV/GI infarct/
Principles of surgical management of aortic valve endocarditis
Appropriate antibiotics 1. Avoidance of contamination of surgical field 2. myocardial protection –important because of prolonged cross clam time required 3. radical resection of all infected tissue 4. minimize prosthetic material 5. valve replacement is usually required aortic homograft may be most resistant to recurrent IE, however, a stented prosthesis there is no difference between bioprosthesis or mechanical 6. If aortic annulus involved resect inflammed areas before insertion defect in annulus can be repair with fresh autologous pericardium 7.If aortic root abscess and/or fistula is present radial resection with bovine pericardium bovine pericardium is resistant to colonization by micro organisms 8. Abscess in fibrous tissue between aortic and mitral valves best approached through the aortic root and roof of LA aortotomy extended into the aortic annulus and roof of LA to expose fibrous aorto-mitral curtain. Abcess excised in block. Often anterior leaflet of mitral valve needs to be excised. If anterior leaflet is excised need to reconstruct a new aorto-mitral curtain triangular shaped bovine patch is sutured to fibrous trigone. MV prosthesis is secured to post annulus and bovine patch. Roof of LA closed with separate pericardial patch Aortic prosthesis is secured to normal aortic annulus and bovine patch
What are options for a patient with patient prosthesis mismatch
Accept PPM (important to do EOA/BSA) to see the degree of BSA Mechanical prosthesis tend to have larger EOA than biological for example a SJM 21 mm has an EOA of 1.7 while a Mosaic has 1.2 Effects of PPM in long term are controversial likely will have persistent symptoms likely will not have as much LV mass regression effect on survival unclear Supra-annular implant tilt valve in non coronary sinus Aortic root enlargement posterior enlargement–Nicks/Manougian Anterior enlargement Stentless porcine valve, homograft, autograft
Surgical management of aortic regurgitation in a type A dissection
Resuspend aortic valve If valve leaflets are normal Resuspension can be accomplished with supra coronary tube graft valve preserving root replacement (reimplantation/remodelling procedures Valved Conduit Stentless aortic root replacement with supracoronary tube graft if contra-indication to mechanical valved conduit
Describe Stanford A, B and Debakey I, II, IIIa, and IIIb
Stanford A: any dissection involving ascending aorta or aortic arch Stanford B: dissection involves only distal to left subclavain Debakey I: Dissection begins in aorta and involves most of or entire aorta Debakey II: involves only the ascending aorta (not the arch) Debakey III: involves only the descending IIIa: starts distal to the left subclavian and does not involve adbominal aorta IIIb: starts distal to the left subclavian and extends beyond diaphragm into supre-renal and abdominal aorta
What is mechanism of action of aprotinin
Serine protease inhibitor from bovine lung 2 mechanisms of action a. Antifibrinolytic–inhibiting trypsin, chymotrypsin, plasmin (prevents breakdown of fibrin by plasmin) b. preservation of platelet function c. Anti-inflammatory inhibits mediators of complement and cellular activation
What are risk factors for paralysis with thoracic aorta surgery
Clamp time > 30 minutes Dissection greater risk then aneurysm Age Peri-operative hypotension Extent of aneurysm Emergency surgery Non use of distal perfusion Pre-op Neuro deficit
What is blood supply to spinal chord
Vertebral, cervical, intercostals and lumbar 3 longitundinal (1 anterior and 2 posterior spinal arteries) Vertebral supply high cord in the neck and give arise to the 3 longitudinal arteries segemental radial arteries come from intercostals and lumbars supply the thoracic and lumbar chord The anterior spinal artery is attenuated and the artery of Adamkiewicz (largest and most important radicular artery) supplies the anterior cord principally in the descending portion (usually originates between T9-L2)
What are strategies to prevent paraplegia
systemic hypothermia epidural cooling distal perfusion re-implantation of spinal arterties steroids avoid hyperglycemia CSF drainage barbiturates
What indications for various pacing modes
VVI: AV block with absence of reliable atrial function. VVIR: desire for rate variability in more active patient DDD: AV block with functional atrium but slow atrial rate provides (AV synchrony) HOCM VDD: AV block with reliable P waves and atrial function, allows AV synchrony with only a single lead
What % of retrograde cariodplegia that returns to the right and left ventricle
70% of flow is nutritive (ie via capillaries and returns to the coronary ostia) most goes to LV nutritive flow. RV flow is minimal but cooling occurs 25-30% of flow is non-nutritive (exits via thesbian and veno-veno- collaterals.
List factors that increase and decrease PVR
Increase Decrease Hypoxia High FiO2 Hypercapnia Hypocapnia Acidosis Alkalosis Atelectasis nitric oxide hypothermia vasodilators High airway pressure sedation vasoconstrictors
50 year old male with ASD Calculate PVR in woods units Calculate the shunt Describe if patient should undergo operation
Criteria to close ASD significant shunt > 1.5: 1 PVR < 6-8 woods untis No cyanosis (no right to left shunt)
What are ways to assess calcium of ascending aorta and classification on epiaortic scanning
History CXR Intra-operative inspection TEE (not very good) but disease of descending aorta >5 mm severe, correlates well with ascending aortic disease, but s not as sensitive as epi-aortic scanning Epi-aortic scan: most sensitive and specific Grading system: Normal no intimal thickening mild < 3mm without irregularities moderate > 3mm with diffuse irregularities and or calcification severe > 5 mm intimal thickening and or large mobile dibris ulcerated plaque and thrombi CT very sensitive
What is the source of emboli from aorta
Existing carotid disease ascending aortia athersclerosis Air Most debris is dislodged during aortic manipulation. Cannulation, clamping and unclamping.
