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B-K Lam, MDCM University of Ottawa Heart Institute A Case Based Review of Cardiac Surgery Objectives for the MCC Qualifying Exam 2009.

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Presentation on theme: "B-K Lam, MDCM University of Ottawa Heart Institute A Case Based Review of Cardiac Surgery Objectives for the MCC Qualifying Exam 2009."— Presentation transcript:

1 B-K Lam, MDCM University of Ottawa Heart Institute A Case Based Review of Cardiac Surgery Objectives for the MCC Qualifying Exam 2009

2 Objectives Using demonstrative cases, this lecture will highlight the cardiac surgical aspects of the differential diagnoses included in the MCC qualifying exam objectivesUsing demonstrative cases, this lecture will highlight the cardiac surgical aspects of the differential diagnoses included in the MCC qualifying exam objectives MCC Objectives for the Qualifying Examination covered in this review:MCC Objectives for the Qualifying Examination covered in this review: –Cardiac arrest (p. 13) –Chest discomfort (p. 14) –Dyspnea (p. 27) Acute (p. 27-1)Acute (p. 27-1) Chronic (p. 27-2)Chronic (p. 27-2) –Diastolic murmur (p. 62-1) –Heart sounds pathological (p. 62-2) –Systolic murmur (p. 62-3) –Trauma Chest injuries – heart injury (p.109-4)Chest injuries – heart injury (p.109-4)

3 Case 1 A 48 year-old man is awakened early in the morning by sharp anterior chest pain that radiates to his back. He presents to the emergency room several hours later reporting that his pain has subsided but he is very short of breath. His past medical history is significant for poorly controlled hypertension. On examination, BP is 150/40, P100, RR 24, 88% on 2L/min of O2. His cardiac exam is noticeable for an absent S2, a loud 4/6 diastolic murmur; he also has an accompanying systolic ejection murmur. You also notice that his left carotid pulse is weaker than his right.A 48 year-old man is awakened early in the morning by sharp anterior chest pain that radiates to his back. He presents to the emergency room several hours later reporting that his pain has subsided but he is very short of breath. His past medical history is significant for poorly controlled hypertension. On examination, BP is 150/40, P100, RR 24, 88% on 2L/min of O2. His cardiac exam is noticeable for an absent S2, a loud 4/6 diastolic murmur; he also has an accompanying systolic ejection murmur. You also notice that his left carotid pulse is weaker than his right.

4 Case 1 - Questions What is the differential diagnosis?What is the differential diagnosis? Why is this patient short of breath?Why is this patient short of breath? Why is his left carotid weak?Why is his left carotid weak? What diagnostic tests would you order?What diagnostic tests would you order? In general, how do you classify this disorder?In general, how do you classify this disorder? How would you classify it in this patient?How would you classify it in this patient? What therapy would you implement in the emergency room?What therapy would you implement in the emergency room? How would you further manage this patient and why?How would you further manage this patient and why?

5 Top 3 DDx MIMI Aortic DissectionAortic Dissection PEPE (Tension Pneumothorax)(Tension Pneumothorax)

6 Acute dyspnea - Ddx CardiacCardiac –Ischemic heart disease (acute myocardial ischemia) –Myocardial dysfunction (congestive heart failure) Ischemic/Hypertensive cardiomyopathyIschemic/Hypertensive cardiomyopathy Dilated (idiopathic, alcoholic, hemochromatosis)Dilated (idiopathic, alcoholic, hemochromatosis) Pericardial disease (tamponade)Pericardial disease (tamponade) Valvular (Mitral regurgitation, Aortic Insufficiency )Valvular (Mitral regurgitation, Aortic Insufficiency ) Pulmonary –Upper airway Aspiration Anaphylaxis –Ventilatory pump: Pleura (pneumothorax), Airways (bronchitis, bronchospasm) –Gas exchanger Pulmonary embolus Pneumonia (viral, bacterial, atypical, fungus) –ARDS Vasculitis (Wegener, Goodpasture) –Respiratory control (metabolic acidosis, ASA toxicity)

7 Weak L carotid Dissection flap causing obstruction of true lumenDissection flap causing obstruction of true lumen

8 Diagnostic Tests CK, TNtCK, TNt ECGECG CXRCXR TEETEE CTCT MRIMRI

9 Classification A B Debakey Stanford

10 What type of dissection Stanford AStanford A Debakey I or IIDebakey I or II

11 Acute Management Beta BlockadeBeta Blockade –Reduces wall stress on aorta –dP/dT –Rupture prevention AntihypertensivesAntihypertensives –Reduces shear stress on the aorta –Anti-impulse/propagation therapy –Nitroglycerine –Nitroprusside

12 Definitive Therapy SurgerySurgery Type A dissection is a surgical emergencyType A dissection is a surgical emergency Terrible natural history:Terrible natural history: –1%/hour rule 50% dead in 48 hours50% dead in 48 hours 70% dead by 1 week70% dead by 1 week Medical Tx = 60% mortality rateMedical Tx = 60% mortality rate –Modes of death Rupture with hemopericardium, hemomediastinum or hemothoraxRupture with hemopericardium, hemomediastinum or hemothorax Organ dysfunctionOrgan dysfunction

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14 Case 2 An 19 year old male is received a single stab wound to the chest outside a night club. He is brought to the ER, conscious and complaining of pain and shortness of breath. On examination, you observe a 3cm wound just left of his sternum in the 5 th interspace. His BP is 85/60, P100, RR18, 95% on 2L/min of O2. His skin is slightly mottled and cool; his JVP is 8cm. By auscultation, air entry is fair bilaterally, heart sounds are muffled and peripheral pulses are weak. The rest of the physical is normal. Shortly after arriving in the patient becomes unresponsive. Pulses are not palpable, the monitor shows normal sinus rhythm.An 19 year old male is received a single stab wound to the chest outside a night club. He is brought to the ER, conscious and complaining of pain and shortness of breath. On examination, you observe a 3cm wound just left of his sternum in the 5 th interspace. His BP is 85/60, P100, RR18, 95% on 2L/min of O2. His skin is slightly mottled and cool; his JVP is 8cm. By auscultation, air entry is fair bilaterally, heart sounds are muffled and peripheral pulses are weak. The rest of the physical is normal. Shortly after arriving in the patient becomes unresponsive. Pulses are not palpable, the monitor shows normal sinus rhythm.

15 Case 2 - Questions What are the most concerning clinical signs?What are the most concerning clinical signs? What is the diagnosis?What is the diagnosis? What structure is most likely injured?What structure is most likely injured? What other structure should you be worried about?What other structure should you be worried about? Prior to arrest what diagnostic tests would you order?Prior to arrest what diagnostic tests would you order? What type of cardiac arrest is this and why has it occurred?What type of cardiac arrest is this and why has it occurred? How would you manage the arrest?How would you manage the arrest?

16 Concerning Clinical Signs HypotensionHypotension TachycardiaTachycardia Muffled heart soundsMuffled heart sounds JVP elevatedJVP elevated Weak peripheral PulsesWeak peripheral Pulses CARDIAC TAMPONADE!

17 Commonly injured Right ventricular injury most commonRight ventricular injury most common –Sits anteriorly in the mediastinum / LV posterior –RV 43%, LV 34%, RA 16%, LA 7% Fatality rate 70-80%Fatality rate 70-80% Survival probability depends on:Survival probability depends on: –Degree of anatomic injury –Occurrence of cardiac standstill Beck triad only in 10-30% of tamponade casesBeck triad only in 10-30% of tamponade cases Pericardiocentesis: 80% false negativePericardiocentesis: 80% false negative FAST U/S: 95% sensitivityFAST U/S: 95% sensitivity

18 Associated Chest Injuries CardiacCardiac –Rule out LAD coronary artery injuries –Valvular injury Lung (pneumo/hemothorax)Lung (pneumo/hemothorax) TracheobronchialTracheobronchial –75-80% involvement of cervical trachea Esophagus (<1%)Esophagus (<1%) Diaphragm (45%)Diaphragm (45%) –15% >2cm, 13% missed with 85% returning with hernia) Thoracic great vessel (0.3-10%)Thoracic great vessel (0.3-10%) –90% due penetrating trauma, 71% hospital survival

19 Diagnostic Tests LabsLabs ECGECG CXRCXR EchoEcho FAST U/SFAST U/S

20 Cardiac Arrest PEA arrestPEA arrest Cardiac tamponade prevents adequate cardiac filling and subsequently cardiac outputCardiac tamponade prevents adequate cardiac filling and subsequently cardiac output This is not hypovolemiaThis is not hypovolemia

21 Arrest Management ABCsABCs IntubationIntubation CPRCPR Manage underlying causeManage underlying cause –5Hs & 5Ts –ER thoracotomy –pericardiocentesis

22 Copyright ©2005 American Heart Association Circulation 2005;112:IV-58-IV-66

23 Case 3 An unrestrained 23 year old driver ran a red light and collided with another vehicle in a t-bone fashion. He is brought to the ER, conscious complaining of sternal pain. On examination, you observe bruising on his anterior chest. HR 115, BP 90/50 and RR15. The patients JVP is flat and lungs are clear. A CXR is performed and it shows a widened mediastinum, a pleural cap and a fracture of the first rib.An unrestrained 23 year old driver ran a red light and collided with another vehicle in a t-bone fashion. He is brought to the ER, conscious complaining of sternal pain. On examination, you observe bruising on his anterior chest. HR 115, BP 90/50 and RR15. The patients JVP is flat and lungs are clear. A CXR is performed and it shows a widened mediastinum, a pleural cap and a fracture of the first rib.

24 Case 3 - Questions Explain the physical findings.Explain the physical findings. What is your differential diagnosis?What is your differential diagnosis? What are the mechanisms of injury in blunt trauma?What are the mechanisms of injury in blunt trauma? What tests would you order?What tests would you order? What are the classic CXR findings for this condition?What are the classic CXR findings for this condition? What is the usual anatomy and mechanism of this injury? (Where does it occur and why?)What is the usual anatomy and mechanism of this injury? (Where does it occur and why?) What is the initial management?What is the initial management? What are the definitive management options?What are the definitive management options?

25 Symptoms HypotensionHypotension TachycardiaTachycardia Low filling pressuresLow filling pressures Hypovolemic shockHypovolemic shock

26 Blunt thoracic trauma - Ddx AortaAorta –Traumatic aortic disruption CardiacCardiac –Contusion –Rupture –MI PulmonaryPulmonary –Pneumothorax –Hemothorax –Pulmonary contusion –Tracheobronchial injury Rib fracture/flail chest Diaphragm rupture Esophageal rupture

27 Mechanisms of Injury CompressionCompression –sternum and vertebrae Fractured sternumFractured sternum –RV or aorta Torsion: attachment pointsTorsion: attachment points –Vena cavae to RA –PVs to LA –Origin of arch vessels –Aortic isthmus Rise in pressureRise in pressure –Chambers or valves Pretre et al NEJM 97

28 Investigations CBCCBC ECGECG CXRCXR FAST U/SFAST U/S Echo/TEEEcho/TEE CT Thorax (if stable)CT Thorax (if stable) AngiogramAngiogram

29 CXR findings Wide mediastinum (supine CXR > 8 cm; upright CXR >6 cm)Wide mediastinum (supine CXR > 8 cm; upright CXR >6 cm) Obscured aortic knob; abnormal aortic contourObscured aortic knob; abnormal aortic contour Left "apical cap" (ie, pleural blood above apex of left lung)Left "apical cap" (ie, pleural blood above apex of left lung) Large left hemothoraxLarge left hemothorax Deviation of nasogastric tube rightwardDeviation of nasogastric tube rightward Deviation of trachea rightward and/or right mainstem bronchus downwardDeviation of trachea rightward and/or right mainstem bronchus downward Wide left paravertebral stripeWide left paravertebral stripe

30 Anatomy and Mechanism Aortic isthmusAortic isthmus DecelerationDeceleration Greatest shear forceGreatest shear force

31 Initial management Advanced Trauma Life Support® (ATLS®)Advanced Trauma Life Support® (ATLS®) ABCDABCD Secondary surveySecondary survey

32 Definitive Management Stat surgical consult as poor natural historyStat surgical consult as poor natural history Conservative RXConservative RX Open repair vs Stent graftOpen repair vs Stent graft

33 Surgery VS Stenting Endovascular stent: –Location beyond subclavian artery –Minimum of 5mm landing zone –Diameter <36mm –Absence of thrombus in fixation areas –Non-tortuous –Adequate access *

34 Case 4 A surprisingly healthy and active 78 year old female presents to you with chest heaviness when she walks. On further questioning she admits to some dyspnea as well and she has been awakened from sleep with dyspnea several times recently. Her only past medical history is a hysterectomy. On physical examination, the BP is 100/80 and the pulse is 80 and regular but slow and delayed in quality. By auscultation, there is a 3/6 crescendo- decrescendo systolic ejection murmur at the right upper sternal border with radiation to the neck. There is no diastolic murmur noted. The rest of the physical exam is normal.A surprisingly healthy and active 78 year old female presents to you with chest heaviness when she walks. On further questioning she admits to some dyspnea as well and she has been awakened from sleep with dyspnea several times recently. Her only past medical history is a hysterectomy. On physical examination, the BP is 100/80 and the pulse is 80 and regular but slow and delayed in quality. By auscultation, there is a 3/6 crescendo- decrescendo systolic ejection murmur at the right upper sternal border with radiation to the neck. There is no diastolic murmur noted. The rest of the physical exam is normal.

35 Case 4 - Questions What is your differential diagnosis?What is your differential diagnosis? What investigations would you order?What investigations would you order? In order of prevalence, what are the three most common causes of aortic stenosis?In order of prevalence, what are the three most common causes of aortic stenosis? In this patient, how do you explain the angina?In this patient, how do you explain the angina? Name the two most commonly used types of valves in aortic valve replacement surgery?Name the two most commonly used types of valves in aortic valve replacement surgery? List the advantages and disadvantages of the valves you identified in the previous question?List the advantages and disadvantages of the valves you identified in the previous question? How is Coumadin monitored? What are the respective therapeutic ranges for a patient with an aortic and mitral prosthesis?How is Coumadin monitored? What are the respective therapeutic ranges for a patient with an aortic and mitral prosthesis? What type of valve would you recommend for this woman?What type of valve would you recommend for this woman?

36 Chronic Dyspnea - Ddx Cardiac ValvularValvular –Aortic Stenosis –MS, AI, MR IschemicIschemic –CAD with SEM CardiomyopathicCardiomyopathic Pulmonary Muscles/nerves/chest wall Lungs/Pleura –Restrictive Airways –obstructive Gas exchange

37 Investigations CBCCBC CXRCXR ECGECG EchoEcho AngiogramAngiogram

38 AS Etiology AcquiredAcquired –Degenerative/Age related CongenitalCongenital –Bicuspid, unicuspid, quadracuspid RheumaticRheumatic

39 Angina in AS Supply Increased LVEDP therefore decreased diastolic coronary flowIncreased LVEDP therefore decreased diastolic coronary flow Decreased diastolic pressureDecreased diastolic pressure Demand Hypertrophied Increased LVEDP

40 Valve types MechanicalMechanical BioprostheticBioprosthetic

41 Pros & Cons MechanicalMechanical –Pros: DurabilityDurability Large EOALarge EOA –Cons: Require anticoagulationRequire anticoagulation Bioprosthetic –Pros: Anticoagulation not required –Cons: Limited durability Smaller EOA

42 Coumadin Monitoring:Monitoring: –INR Theraputic Range:Theraputic Range: –Mechanical Aortic –Mechanical Mitral


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