B-K Lam, MDCMUniversity of Ottawa Heart Institute

A Case Based Review of Cardiac A Case Based Review of Cardiac Surgery Objectives for the MCC Surgery Objectives for the MCC

Qualifying Exam 2009Qualifying Exam 2009

ObjectivesObjectives• Using demonstrative cases, this lecture will highlight the Using demonstrative cases, this lecture will highlight the

cardiac surgical aspects of the differential diagnoses cardiac surgical aspects of the differential diagnoses included in the MCC qualifying exam objectivesincluded in the MCC qualifying exam objectives

• MCC Objectives for the Qualifying Examination covered MCC Objectives for the Qualifying Examination covered in this review: in this review: – Cardiac arrest (p. 13)Cardiac arrest (p. 13)– Chest discomfort (p. 14)Chest discomfort (p. 14)– Dyspnea (p. 27)Dyspnea (p. 27)

• Acute (p. 27-1)Acute (p. 27-1)• Chronic (p. 27-2)Chronic (p. 27-2)

– Diastolic murmur (p. 62-1)Diastolic murmur (p. 62-1)– Heart sounds pathological (p. 62-2)Heart sounds pathological (p. 62-2)– Systolic murmur (p. 62-3)Systolic murmur (p. 62-3)– TraumaTrauma

• Chest injuries – heart injury (p.109-4) Chest injuries – heart injury (p.109-4)

Case 1Case 1

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

Case 1 - QuestionsCase 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 What therapy would you implement in the

emergency room?emergency room?• How would you further manage this patient and How would you further manage this patient and

why?why?

““Top 3” DDxTop 3” DDx

• MIMI

• Aortic DissectionAortic Dissection

• PEPE

• (Tension Pneumothorax)(Tension Pneumothorax)

Acute dyspnea - DdxAcute dyspnea - Ddx

• Cardiac Cardiac – Ischemic heart disease Ischemic heart disease

(acute myocardial (acute myocardial ischemia)ischemia)

– Myocardial dysfunction Myocardial dysfunction (congestive heart failure)(congestive heart failure)

• Ischemic/Hypertensive Ischemic/Hypertensive cardiomyopathycardiomyopathy

• Dilated (idiopathic, Dilated (idiopathic, alcoholic, alcoholic, hemochromatosis)hemochromatosis)

• Pericardial disease Pericardial disease (tamponade)(tamponade)

• Valvular (Mitral Valvular (Mitral

regurgitation, regurgitation, Aortic Aortic InsufficiencyInsufficiency))

• PulmonaryPulmonary– Upper airwayUpper airway

• AspirationAspiration• AnaphylaxisAnaphylaxis

– Ventilatory pump: Ventilatory pump: • Pleura (pneumothorax),Pleura (pneumothorax),• Airways (bronchitis, Airways (bronchitis,

bronchospasm)bronchospasm)– Gas exchangerGas exchanger

• Pulmonary embolusPulmonary embolus• Pneumonia (viral, Pneumonia (viral,

bacterial, atypical, fungus)bacterial, atypical, fungus)– ARDSARDS

• Vasculitis (Wegener, Vasculitis (Wegener, Goodpasture)Goodpasture)

– Respiratory control Respiratory control (metabolic acidosis, ASA (metabolic acidosis, ASA toxicity)toxicity)

Weak L carotidWeak L carotid

• Dissection flap causing obstruction of true Dissection flap causing obstruction of true lumenlumen

Diagnostic TestsDiagnostic Tests

• CK, TNtCK, TNt

• ECGECG

• CXRCXR

• TEETEE

• CTCT

• MRIMRI

ClassificationClassification

A B

Debakey

Stanford

What type of dissectionWhat type of dissection

• Stanford AStanford A

• Debakey I or IIDebakey I or II

Acute ManagementAcute Management

• Beta BlockadeBeta Blockade– Reduces wall stress on aorta Reduces wall stress on aorta – dP/dTdP/dT– Rupture preventionRupture prevention

• AntihypertensivesAntihypertensives– Reduces shear stress on the aortaReduces shear stress on the aorta– Anti-impulse/propagation therapyAnti-impulse/propagation therapy– Nitroglycerine Nitroglycerine – NitroprussideNitroprusside

Definitive TherapyDefinitive Therapy

• SurgerySurgery• Type A dissection is a surgical emergencyType A dissection is a surgical emergency• Terrible natural history:Terrible natural history:

– ““1%/hour” rule1%/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 deathModes of death• Rupture with hemopericardium, hemomediastinum or Rupture with hemopericardium, hemomediastinum or

hemothoraxhemothorax• Organ dysfunctionOrgan dysfunction

Case 2Case 2• An 19 year old male is received a single stab wound An 19 year old male is received a single stab wound

to the chest outside a night club. He is brought to the to the chest outside a night club. He is brought to the ER, conscious and complaining of pain and ER, conscious and complaining of pain and shortness of breath. On examination, you observe a shortness of breath. On examination, you observe a 3cm wound just left of his sternum in the 53cm wound just left of his sternum in the 5thth interspace. His BP is 85/60, P100, RR18, 95% on interspace. His BP is 85/60, P100, RR18, 95% on 2L/min of O2. His skin is slightly mottled and cool; 2L/min of O2. His skin is slightly mottled and cool; his JVP is 8cm. By auscultation, air entry is fair his JVP is 8cm. By auscultation, air entry is fair bilaterally, heart sounds are muffled and peripheral bilaterally, heart sounds are muffled and peripheral pulses are weak. The rest of the physical is normal. pulses are weak. The rest of the physical is normal. Shortly after arriving in the patient becomes Shortly after arriving in the patient becomes unresponsive. Pulses are not palpable, the monitor unresponsive. Pulses are not palpable, the monitor shows normal sinus rhythm.shows normal sinus rhythm.

Case 2 - QuestionsCase 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 Prior to arrest what diagnostic tests would you

order?order?• What type of cardiac arrest is this and why has it What type of cardiac arrest is this and why has it

occurred?occurred?• How would you manage the arrest?How would you manage the arrest?

Concerning Clinical SignsConcerning Clinical Signs

• HypotensionHypotension

• TachycardiaTachycardia

• Muffled heart soundsMuffled heart sounds

• JVP elevatedJVP elevated

• Weak peripheral PulsesWeak peripheral Pulses

CARDIAC TAMPONADE!CARDIAC TAMPONADE!

Commonly injuredCommonly injured

• Right ventricular injury most commonRight ventricular injury most common– Sits anteriorly in the mediastinum / LV posteriorSits anteriorly in the mediastinum / LV posterior– RV 43%, LV 34%, RA 16%, LA 7%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 injuryDegree of anatomic injury– Occurrence of cardiac standstillOccurrence 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

Associated Chest InjuriesAssociated Chest Injuries

• CardiacCardiac– Rule out LAD coronary artery injuriesRule out LAD coronary artery injuries– Valvular injuryValvular injury

• Lung (pneumo/hemothorax)Lung (pneumo/hemothorax)• Tracheobronchial Tracheobronchial

– 75-80% involvement of cervical trachea75-80% involvement of cervical trachea

• Esophagus (<1%) Esophagus (<1%) • Diaphragm (45%)Diaphragm (45%)

– 15% >2cm, 13% missed with 85% returning with hernia)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 survival90% due penetrating trauma, 71% hospital survival

Diagnostic TestsDiagnostic Tests

• LabsLabs

• ECGECG

• CXRCXR

• EchoEcho

• FAST U/SFAST U/S

Cardiac ArrestCardiac Arrest

• PEA arrestPEA arrest

• Cardiac tamponade prevents adequate Cardiac tamponade prevents adequate cardiac filling and subsequently cardiac cardiac filling and subsequently cardiac outputoutput

• This is not hypovolemiaThis is not hypovolemia

Arrest ManagementArrest Management

• ABC’sABC’s

• IntubationIntubation

• CPRCPR

• Manage underlying causeManage underlying cause– 5H’s & 5T’s5H’s & 5T’s– ER thoracotomyER thoracotomy– pericardiocentesispericardiocentesis

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

Case 3Case 3

• An unrestrained 23 year old driver ran a An unrestrained 23 year old driver ran a red light and collided with another vehicle red light and collided with another vehicle in a t-bone fashion. He is brought to the in a t-bone fashion. He is brought to the ER, conscious complaining of sternal pain. ER, conscious complaining of sternal pain. On examination, you observe bruising on On examination, you observe bruising on his anterior chest. HR 115, BP 90/50 and his anterior chest. HR 115, BP 90/50 and RR15. The patient’s JVP is flat and lungs RR15. The patient’s JVP is flat and lungs are clear. A CXR is performed and it are clear. A CXR is performed and it shows a widened mediastinum, a pleural shows a widened mediastinum, a pleural cap and a fracture of the first rib.cap and a fracture of the first rib.

Case 3 - QuestionsCase 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 What are the mechanisms of injury in blunt

trauma?trauma?• What tests would you order?What tests would you order?• What are the classic CXR findings for this What are the classic CXR findings for this

condition?condition?• What is the usual anatomy and mechanism of What is the usual anatomy and mechanism of

this injury? (Where does it occur and why?)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?

SymptomsSymptoms

• HypotensionHypotension

• TachycardiaTachycardia

• Low filling pressuresLow filling pressures

• Hypovolemic shockHypovolemic shock

Blunt thoracic trauma - DdxBlunt thoracic trauma - Ddx

• AortaAorta– Traumatic aortic disruptionTraumatic aortic disruption

• CardiacCardiac– ContusionContusion– RuptureRupture– MIMI

• PulmonaryPulmonary– PneumothoraxPneumothorax– HemothoraxHemothorax– Pulmonary contusionPulmonary contusion– Tracheobronchial injuryTracheobronchial injury

• Rib fracture/flail chestRib fracture/flail chest• Diaphragm ruptureDiaphragm rupture• Esophageal ruptureEsophageal rupture

Mechanisms of InjuryMechanisms of Injury• Compression Compression

– sternum and vertebraesternum and vertebrae

• Fractured sternumFractured sternum– RV or aortaRV or aorta

• Torsion: attachment pointsTorsion: attachment points– Vena cavae to RAVena cavae to RA– PV’s to LAPV’s to LA– Origin of arch vesselsOrigin of arch vessels– Aortic isthmusAortic isthmus

• Rise in pressureRise in pressure– Chambers or valves Chambers or valves

Pretre et al NEJM 97Pretre et al NEJM 97

InvestigationsInvestigations

• CBCCBC

• ECG ECG

• CXRCXR

• FAST U/SFAST U/S

• Echo/TEEEcho/TEE

• CT Thorax (if stable)CT Thorax (if stable)

• AngiogramAngiogram

CXR findingsCXR findings

• Wide mediastinum (supine Wide mediastinum (supine CXR > 8 cm; upright CXR >6 CXR > 8 cm; upright CXR >6 cm) cm)

• Obscured aortic knob; Obscured aortic knob; abnormal aortic contour abnormal aortic contour

• Left "apical cap" (ie, pleural Left "apical cap" (ie, pleural blood above apex of left lung) blood above apex of left lung)

• Large left hemothorax Large left hemothorax • Deviation of nasogastric tube Deviation of nasogastric tube

rightward rightward • Deviation of trachea rightward Deviation of trachea rightward

and/or right mainstem and/or right mainstem bronchus downward bronchus downward

• Wide left paravertebral stripe Wide left paravertebral stripe

Anatomy and MechanismAnatomy and Mechanism

• Aortic isthmusAortic isthmus

• DecelerationDeceleration

• Greatest shear forceGreatest shear force

Initial managementInitial management

• Advanced Trauma Life Support® (ATLS®) Advanced Trauma Life Support® (ATLS®)

• ABCDABCD

• Secondary surveySecondary survey

Definitive ManagementDefinitive Management

• Stat surgical consult as poor natural Stat surgical consult as poor natural historyhistory

• Conservative RXConservative RX

• Open repair vs Stent graftOpen repair vs Stent graft

Surgery VS StentingSurgery VS Stenting

• Endovascular stent:Endovascular stent:– Location beyond Location beyond

subclavian arterysubclavian artery– Minimum of 5mm Minimum of 5mm

landing zonelanding zone– Diameter <36mmDiameter <36mm– Absence of thrombus Absence of thrombus

in fixation areasin fixation areas– Non-tortuousNon-tortuous– Adequate access Adequate access

**

Case 4Case 4

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

Case 4 - QuestionsCase 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 In order of prevalence, what are the three most common

causes of aortic stenosis?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 Name the two most commonly used types of valves in

aortic valve replacement surgery?aortic valve replacement surgery?• List the advantages and disadvantages of the valves List the advantages and disadvantages of the valves

you identified in the previous question?you identified in the previous question?• How is Coumadin monitored? What are the respective How is Coumadin monitored? What are the respective

therapeutic ranges for a patient with an aortic and mitral therapeutic ranges for a patient with an aortic and mitral prosthesis?prosthesis?

• What type of valve would you recommend for this What type of valve would you recommend for this woman?woman?

Chronic Dyspnea - DdxChronic Dyspnea - Ddx

CardiacCardiac• ValvularValvular

– Aortic StenosisAortic Stenosis– MS, AI, MRMS, AI, MR

• IschemicIschemic– CAD with SEMCAD with SEM

• CardiomyopathicCardiomyopathic

PulmonaryPulmonary• Muscles/nerves/chest Muscles/nerves/chest

wallwall• Lungs/PleuraLungs/Pleura

– RestrictiveRestrictive

• AirwaysAirways– obstructiveobstructive

• Gas exchangeGas exchange

InvestigationsInvestigations

• CBCCBC

• CXRCXR

• ECGECG

• EchoEcho

• AngiogramAngiogram

AS EtiologyAS Etiology

• AcquiredAcquired– Degenerative/Age relatedDegenerative/Age related

• CongenitalCongenital– Bicuspid, Bicuspid, unicuspid, quadracuspidunicuspid, quadracuspid

• RheumaticRheumatic

Angina in ASAngina in AS

SupplySupply• Increased LVEDP Increased LVEDP

therefore decreased therefore decreased diastolic coronary flowdiastolic coronary flow

• Decreased diastolic Decreased diastolic pressurepressure

DemandDemand• Hypertrophied Hypertrophied • Increased LVEDPIncreased LVEDP

Valve typesValve types

• MechanicalMechanical

• BioprostheticBioprosthetic

Pros & ConsPros & Cons

• MechanicalMechanical– Pros:Pros:

• DurabilityDurability• Large EOALarge EOA

– Cons:Cons:• Require anticoagulationRequire anticoagulation

• BioprostheticBioprosthetic– Pros:Pros:

• Anticoagulation not Anticoagulation not requiredrequired

– Cons:Cons:• Limited durabilityLimited durability• Smaller EOASmaller EOA

CoumadinCoumadin

• Monitoring:Monitoring:– INRINR

• Theraputic Range:Theraputic Range:– Mechanical Aortic 2.0-3.0Mechanical Aortic 2.0-3.0– Mechanical Mitral 2.5-3.5Mechanical Mitral 2.5-3.5