Cardio - Surgery

Question 1

What is acute limb ischemia?

Answer 1

Manifestation of arterial insufficiency
Etiology: cardiac/arterial embolus (eg AF, LV thrombus, IE), arterial thrombosis (eg PVD), iatrogenic/blunt trauma
Presentation: pain, pallor, paresthesias, pulselessness, poikilothermia (cool extremity), paralysis (late)
Mgmt: anticoagulation (eg heparin- prevents further thrombus propagation and thrombosis in the distal arterial and venous circulation), thrombolysis v surgery

Question 2

What is the ankle-brachial index?

Answer 2

Ratio of systolic pressure in ankle/arm.
Used as screening and/or diagnostic tool in pts w/ suspected peripheral arterial disease.
First step to confirm the diagnosis.

Question 3

What is the arterial doppler study or duplex u/s?

Answer 3

Identifies presence and location of acute arterial occlusion.

Question 4

What is an arterial thrombus?

Answer 4

Usually develops at site of an atherosclerotic plaque in pts with pre-existing peripheral vascular disease.

Question 5

What is an aortic aneurysm?

Answer 5

RF: >60yo, smokers, men, hx of atherosclerosis or connective tissue diseases
Presentation: pulsatile abdominal mass, sudden-onset, severe abdominal pain (common), hemodynamic instability (symptomatic hypotension-syncope, w/ weakness and diaphoresis), flank ecchymoses
Rapid expansion - dull abd/back pain, distal embolization
Rupture - sudden, severe abd/back pain +/-shock, umbilical/flank hematoma
XR: prevertebral aortic calcifications
Mgmt: smoking cessation, elective repair for size >5.5cm (asymptomatic), urgent repair for symptomatic and HD stable pts, emergency repair for symptomatic and HD unstable pts

Question 6

What are the manifestations of syphilis?

Answer 6

Primary - painless genital ulcer (chancre)
Secondary - diffuse rash (palms and soles), lymphadenopathy (epitrochlear), condyloma lata, oral lesions, hepatitis
Latent - asymptomatic
Tertiary - CNS (tabes dorsalis, dementia), cardiovascular (aortic aneurysm/insufficiency), cutaneous (gummas)
-tabes dorsalis (disease of posterior spinal columns and dorsal nerve roots)
-thoracic aortic aneurysm - hoarseness due to compression of L recurrent laryngeal nerve, visible suprasternal notch pulsation

Question 7

What is Turner’s syndrome?

Answer 7

Due to partial or complete loss of an X chromosme, 45X
Presentation: short stature, webbed neck, coarctation of aorta, bicuspid aortic valve, horseshoe kidney, streak ovaries, amenorrhea and infertility
Complications: aortic dissection, risk increased due to hemodynamic changes of pregnancy

Question 8

What is an aortic dissection?

Answer 8

RF: hx of HTN, marfan syndrome, cocaine use
Presentation: sudden onset severe sharp/tearing chest or back pain that can radiate to neck and abdomen
Nerve ischemia can lead to extremity tingling
Asymmetry of pulses or BP, >20mmHg variation in SBP between arms, hypotension, aortic regurgitation
Type A: involve ascending aorta, can lead to aortic rupture into pericardial space and hemopericardium
Pleural effusion: due to either direct extension causing hemothorax or from an inflammatory reaction to blood irritating the pleural lining
D-dimer elevation is common (sensitive, but not specific)
Complications: syncope, stroke, MI, HF
XR: mediastinal widening, pericardial effusion
Dx: CT angiography in HD stable pts (w/ no evidence renal dysfunction, it can reveal an intimal flap separating the true and false lumens), ECG - normal or nonspecific ST and T wave changes
Tx: pain ctrl (morphine), IV beta blockers (eg esmolol), +/- sodium nitroprusside (if SBP >120), emergent surgical repair for ascending dissection

Question 9

What is aortic stenosis?

Answer 9

Severe AS criteria - aortic jet velocity >4m/s or mean transvalvular pressure gradient >40mmHg
Indications for valve replacement - Severe AS + >1 of the following -
onset of sxs (angina, syncope),
LVEF <50%,
undergoing other cardiac surgery (eg CABG)

Question 10

What is a cardiac myxoma?

Answer 10

Tumor characteristics: benign neoplasm, 80% located in LA
Presentation: position dependent mitral valve obstruction - mid-diastolic murmur, dyspnea, lightheadedness, syncope; emobilzation of tumor fragments (eg stroke), constitutional sxs (fever, wt loss)
Mid-diastolic rumble at apex murmur
Dx and mgmt: echocardiography and prompt surgical resection

Question 11

What is an arteriovenous fistula?

Answer 11

Arterial pressure exceeds venous pressure, leading to continuous bruit w/ palpable thrill
Distal pulses may be diminished in affected extremity
Untreated AVF can progressively enlarge and lead to limb edema (due to venous HTN), limb ischemia (due to redirection of arterial blood flow), high output heart failure (due to blood returning to RA w/o passing through peripheral resistance)
Dx: duplex u/s
Mgmt: small AVF - obs (sometimes resulting in spontaneous closure) or u/s-guided compression;
large AVF - surgical repair

Question 12

What are the complications of cardiac catheterization?

Answer 12

Hematoma w/in 12h: +/- mass, no bruit, sudden HD instability, ipsilateral flank or back pain; dx: abd CT scan w/o contrast or abd u/s; tx: bed rest, obs, IV fluids and/or blood transfusion

Pseudoaneurysm - bulging, pulsatile mass, systolic bruit
Arteriovenous fistula - no mass, continuous bruit

Question 13

What is blunt thoracic trauma?

Incomplete rupture may result in:
creation of secondary, false lumen similar to dissection
Creation of pseudocoarctation, resulting in proximal HTN and distal hypotension (UE HTN and diminished femoral pulses)
Expansion of adventitia under high flow pressure, causing compression/stretching of surrounding structures such as left recurrent laryngeal nerve (eg hoarse voice)

Answer 13

RF: pt involved in MVA or falls from >10ft; high-energy, blunt, rapid deceleration trauma to chest
Dx: upright CXR showing mediastinal widening/deviation to the R, and L-sided hemothorax
CT ANGIO of chest is highly sensitive and specific for thoracic aortic injury and is readily available
TEE does NOT adequately visualize the thoracic aorta, which progressively becomes more posterior as it arches and transitions to descening aorta
Mgmt: antihypertensive therapy, immediate operative repair

Question 14

What is myocardial contusion?

Answer 14

Classically causes tachycardia, new bundle branch blocks or arrhythmia
Sternal fracture is a commonly assoc. finding

Question 15

What is sternal dehiscence?

Answer 15

A complication of cardiac surgery that occurs when the 2 approximated edges of the bony sternum separate, due to loosening or fracture of suture wire
RF: impaired wound healing, obesity, large breasts
Presentation: mild pain or sensation of chest wall instability and “clicking” with chest movement
Dx: imaging or clinical -palpable rocking or clicking of sternum
Tx: urgent surgical exploration, debridement, sternal fixation to prevent cardiac damage from loose wire or bone fragments

Question 16

What is mediastinitis?

Answer 16

Complication of cardiovascular surgery characterized by infection of deep tissues
Classic presentation: systemic symptoms (fever, tachycardia), chest pain, chest wall edema/crepitus, purulent discharege
Dx: chest and sternal imaging (eg mediastinal fluid/pus collections or pneumomediastinum on CT scan)
XR: mediastinal widening
Tx: emergent surgical debridement, drainage, tissue cultures, and empiric IV abx

Question 17

What is acute cardiac tamponade?

Answer 17

Etiology: can be catastrophic complication of acute aortic dissection, aortic aneurysm or postmyocardial infarction, malignancy or radiation therapy, infection (eg viral, tuberculosis), connective tissue disease (SLE), cardiovasc surgery
Presentation: Beck’s triad (hypotension unresponsive to fluids, elevated JVP, muffled heart sounds), tachycardia, pulsus paradoxus (SBP decreases by >10 with inspiration)
Only 100-200ml of blood needed to cause sudden rise in intrapericardial pressure compressing cardiac chambers, venous return, and CO
Elevation and equalization of all intracardiac diastolic pressures (RA, RV, and PCWP-LA)
DX: ECG - low voltage QRS, electrical alternans,
XR: normal lungs, enlarged cardiac silhouette; echocardiogram* - RA and ventricular collapse, plethora of the IVC
Tx: decompression by pericardiocentesis or surgical pericardiotomy to remove small fluid and reduce high intrapericardial pressure acutely

Question 18

What is a central venous catheter?

Answer 18

Commonly used for administration of critical care medications (pressors, hypertonic saline)
Preferred pts of central venous access are internal jugular vein or subclavian vein
Complications are due to inappropriate catheter placement which can cause lung puncture, leading to pneumothorax, or myocardial perforation leading to pericardial tamponade
Portable CXR should be performed immediately to identify misplaced catheter tip, possible injury (eg pneumothorax) and prevent exacerbation of injury
Visualization of catheter tip just proximal to angle between trachea and right mainstem bronchus confirms appropriate placement

Question 19

What is Ehlers-Danlos?

Answer 19

Genetics - AD; COL5A1 and COL5A2 mutation
Features:
Skin - transparent and hyper-extensible, easy bruising, poor healing, cigarette/paper like scarring w/ atrophy
MSK - jt hypermobility/jt dislocations, pectus excavatum, scoliosis, high, arched palate
Cardiac - mitral valve prolapse
Other - abd and inguinal hernias, uterine prolapse

Question 20

What is Marfan syndrome?

Answer 20

Genetics - AD; FBN1 mutation
Skin - striae
MSK - jt hypermobility, pectus excavatum or carinatum, scoliosis, tall w/ long extremities
Cardiac - progressive aortic root dilation, aortic regurgitation, dissection, mitral valve prolapse
Other - lens and retinal detachment, spontaneous pneumothorax

Question 21

What is atrial fibrillation?

Answer 21

Afib commonly occurs w/in a few days after CABG, usually is self-limited w/ resolution
Less than 24h; rate control (beta blockers or amiodarone) is best
Greater than 24h after CABG: Anticoagulation and/or cardioversion

Question 22

What are peripheral artery aneurysms?

Answer 22

Associated with abdominal aortic aneurysm
Manifests as a pulsatile mass that can compress adjacent structures (nerves, veins), and can result in thrombosis and ischemia
Popliteal artery aneursym is most common.
Femoral artery aneurysm is second most common. Presents as pulsatile mass below inguinal ligament; anterior thigh pain is due to compression of femoral nerve that runs lateral to the artery

Question 23

What is Leriche syndrome (aortoiliac occlusion)?

Answer 23

RF: men, predisposition for atherosclerosis, smokers
Triad - bilateral hip/thigh/buttock claudication, absent or diminished femoral pulses (symmetric atrophy of bilateral LE due to chronic ischemia), impotence

Question 24

What is hypovolemic shock?

Answer 24

Characterized by initial decrease in preload and CO, followed by compensatory increase in SVR, HR, and EF
Positive pressure mechanical ventilation can cause acute increase in intrathoracic pressure, which can collapse the IVC and cut off venous return
Sedatives used prior to intubation can cause relaxation of venous capacitance vessels–> decrease venous return
Presentation: hypotension, tachycardia, cold extremities, evidence of poor organ perfusion (somnolence, unresponsiveness), flat neck veins (evidence of hypovolemia)

Question 25

What is prosthetic valve dysfunction?

Answer 25

Types and causes:
transvalvular regurgitation (cusp degeneration; regurg thru the valve; bioprosthetic valves affected more),
paravalvular leak (annular degeneration; mechanical valves affected more, IE; regurg around the valve),
valvular obstruction/stenosis (valve trombus)
Presentation: New murmur (regurgitant or stenotic), macroangiopathic hemolytic anemia, HF symptoms, thromboembolism
Dx: echocardiography (allows visualization of the valve and surrounding anatomy)

Question 26

What is hepatojugular reflux/abdominojugular reflux?

Answer 26

Elicited by applying firm and sustained pressure for 10-15s over upper abdomen.
Positive = sustained elevation of jugular venous pressure >3cm during continued abdominal compression
A reflection of a failing RV that cannot accommodate an increase in venous return w/ abdominal compression
Commonly due to: constrictive pericarditis, RV infarction, and restrictive cardiomyopathy

Question 27

Supraventricular tacycardia/paroxysmal supraventricular tacycardia (PSVT

Answer 27

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of PSVT caused by reentry mechanism due to presence of dual electrical pathway (slow and fast pathway) in the AV node
Palpitations are most common presentation, but some patients may have dizziness, SOB, or chest pain
Vagal maneuvers (eg carotid sinus massage, cold water immersion or diving reflex, valsava maneuver, eyeball pressure) increases PNS tone in the heart and result in temporary slowing of conduction in the AV node and an increase in the AV node refractory period leading to termination of AVNRT