Cardiac Surgery

A

History

• 1.

  History of present illness—detailed account of symptom chronology: acute versus chronic

  • a.

    Angina—stable or unstable, arrhythmia, congestive heart failure

  • b.

    Timing of recent intervention

  • c.

    Dyspnea: New York Heart Association (NYHA) functional classification for heart failure

    • (1)

      Class I: no limitations during ordinary activity, asymptomatic

    • (2)

      Class II: slight limitation during ordinary activity

    • (3)

      Class III: marked limitation of ordinary activity

    • (4)

      Class IV: no physical activity without symptoms

  • d.

    Arrhythmia, palpitations, peripheral edema

• 2.

  Medical and surgical history—detailed

  • a.

    Prior sternotomy

  • b.

    Recent percutaneous coronary intervention (PCI)

• 3.

  Medications and allergies—detailed list and dosages

  • a.

    Current anticoagulation use; clopidogrel should be stopped 5 days before surgery

• 4.

  Social history, including tobacco, ethyl alcohol, and drug use

• 5.

  Family history

• 6.

  Review of symptoms

B

Physical Examination—Complete and Systems Based

• 1.

  Neurologic—cranial nerves, strength, and motor bilaterally

• 2.

  Pulmonary—rales, rhonchi, wheezing (pneumonia, congestive heart failure, chronic obstructive pulmonary disease)

• 3.

  Cardiovascular

  • a.

    Signs or symptoms of congestive heart failure—jugular venous distention, rales, S3 gallop

  • b.

    Arrhythmias, presence of a pacemaker, and/or defibrillator

  • c.

    Previous sternotomy/thoracotomy incisions, chest tubes

  • d.

    Vascular examination

    • (1)

      Documentation of peripheral pulses—radial, ulnar, femoral, dorsalis pedis

    • (2)

      Evidence of tissue loss or ischemic extremities

    • (3)

      Evaluation of carotid disease, bruits

    • (4)

      Evaluation of neck/groin for potential internal jugular/femoral cannulation

    • (5)

      Evaluation of conduit suitability (radial arteries, saphenous veins, blood pressure in both arms)

  • e.

    Heart murmurs

    • (1)

      Systolic ejection: aortic stenosis (AS) (radiates to carotids), pulmonary stenosis, atrial septal defect (ASD), innocent flow murmurs

    • (2)

      Pansystolic: mitral regurgitation (MR) (radiates to axilla), tricuspid regurgitation, ventricular septal defect (VSD), patent ductus arteriosus (PDA)

    • (3)

      Early diastolic: aortic insufficiency (AI), pulmonary regurgitation

• 4.

  Gastrointestinal—old incisions, hernia

• 5.

  Musculoskeletal—strength, sensation, gait, among others

C

Preoperative Testing

• 1.

  Electrocardiogram—arrhythmias, ischemic changes, conduction delays, chamber enlargement

• 2.

  Laboratory—complete blood cell count, electrolytes, coagulation profile, type and crossmatch for 2 units of packed red blood cells

• 3.

  Posteroanterior and lateral chest radiograph—visualize plane between sternum and heart on lateral

• 4.

  Nuclear perfusion testing

  • a.

    Myocardial reserve—hibernating myocardium that may benefit from revascularization

  • b.

    Functional significance of coronary lesion

• 5.

  Cardiac catheterization and echocardiogram

  • a.

    Distribution of coronary artery disease

  • b.

    Evaluation of ventricular wall motion and ejection fraction function and wall motion

  • c.

    Presence of valvular dysfunction

• 6.

  Risk calculator (STS, EuroScore, Seattle Heart Failure Models)

D

Preoperative Orders

• 1.

  Accurate height and weight recorded in chart to calculate body surface area

• 2.

  Twelve-lead electrocardiogram

• 3.

  Posteroanterior and lateral chest radiograph (recent)

• 4.

  Hibiclens scrub and clipper prep to chest the night before surgery

• 5.

  Nothing by mouth (NPO) after midnight

• 6.

  Antibiotics on call—cefuroxime 1.5 g intravenous (IV) on call or use vancomycin 1 g IV for reoperative/valve patients

• 7.

  Medications

  • a.

    In general, medications are continued until surgery, especially antianginal agents, antihypertensive agents with the exception of angiotensin-converting enzyme (ACE) inhibitors, nitroglycerin, and heparin drips (hold hours before surgery).

  • b.

    Continue all antiarrhythmic agents.

  • c.

    Perioperative steroid and insulin coverage is per routine.

  • d.

    Ensure appropriate discontinuation of anticoagulants.

• 8.

  Perioperative monitors generally placed immediately before operation

  • a.

    Right radial/brachial radial/brachial arterial line

  • b.

    Swan-Ganz catheter (some institutions omit this step for straightforward procedures)

A

Coronary Artery Bypass Grafting

• 1.

  Indications

  • a.

    Chronic stable angina unrelieved by medication/asymptomatic angina—left main disease, left main equivalent disease (proximal left anterior descending [LAD] and proximal circumflex arteries), three-vessel disease

  • b.

    Unstable angina despite treatment/stable angina—left main disease, left main equivalent, three-vessel disease, two-vessel disease with proximal LAD and reduced ventricular function (left ventricular ejection fraction [LVEF] <50%)

  • c.

    Acute myocardial infarction—if significant coronary disease exists beyond the area of infarction, ongoing angina after infarction, or unstable hemodynamic status. Controversy exists on the timing of surgical intervention. Unstable angina/non–ST elevation myocardial infarction (NSTEMI)—left main, left main equivalent disease

  • d.

    Ventricular arrhythmias with coronary disease/ST elevation myocardial infarction (STEMI)—failed PCI or anatomically not a PCI candidate

  • e.

    Failed percutaneous transluminal coronary angioplasty/poor LV function—left main disease, left main equivalent, proximal LAD and two-vessel disease

  • f.

    Life-threatening ventricular arrhythmias—left main, three-vessel disease

  • g.

    Failed PCI—shock with ongoing ischemia

• 2.

  Coronary artery bypass grafting (CABG) has been shown to be superior to medical treatment of coronary disease in the following situations:

  • a.

    In patients with asymptomatic or mild angina and the following conditions:

    • (1)

      Significant left main disease (Veterans Affairs Cooperative Study 1972–74)

    • (2)

      Three-vessel coronary artery disease with proximal left anterior descending disease or double-vessel disease in conjunction with left main disease (European Coronary Surgery Study Group 1973–76)

    • (3)

      Three-vessel disease and ventricular dysfunction (Coronary Artery Surgery Study 1975–79)

  • b.

    In patients with chronic moderate-to-severe angina

  • c.

    Unstable angina despite full medical therapy

  • d.

    Failed percutaneous transluminal coronary angioplasty with reasonable targets

  • e.

    Persistent ventricular arrhythmias in patients with coronary artery disease

  • f.

    Patients with diabetes with double-vessel disease—reduced ventricular function

• 3.

  There is no difference in rates of myocardial infarction in CABG and medically treated patients.

• 4.

  PCI is acceptable treatment option for single-vessel disease or two-vessel disease. CABG has been shown to be superior to drug-eluting stent (DES) PCI in patients with complex coronary disease, such as left main or three-vessel disease. CABG has been shown to have lower incidence of revascularization and myocardial infarction (MI) in the Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) trial.

• 5.

  Internal mammary artery grafts are the conduit of choice because of superior patency rates compared with saphenous vein grafts (in situ and free grafts) (90%–95% vs. 50%–60% at 10 years). Patency rates for the internal mammary artery compared with the great saphenous vein graft at 10 and 15 years are 95% and 88% and 61% and 32%, respectively. Radial artery and less commonly gastroepiploic artery may be used as conduit.

• 6.

  Off-pump CABG is an approach used to minimize aortic manipulation and avoid the systemic effects of cardiopulmonary bypass. On-pump versus off-pump CABG shows no difference in outcomes, with off-pump surgery conferring a lower initial stroke risk that was not clinically significant and a trend toward lower number of target vessels grafted.

B

Valve Replacement or Repair

• 1.

  AS

  • a.

    It is commonly caused by bicuspid valve, rheumatic disease, or calcific/degenerative AS.

  • b.

    Symptoms include triad of dyspnea, angina, and syncope.

  • c.

    AS severity

    • (1)

      Mild AS: aortic valve area greater than 1.5 cm ² , mean pressure gradient less than 25 mm Hg, peak jet velocity less than 3.0 m/s

    • (2)

      Moderate AS: aortic valve area 1.0–1.5 cm ² , mean pressure gradient 25–40 mm Hg, peak jet velocity 3.0–4.0 m/s

    • (3)

      Severe AS: aortic valve area less than 1.0 cm ² , mean pressure gradient greater than 40 mm Hg, peak jet velocity greater than 4.0 m/s

  • d.

    Indications for surgery

    • (1)

      Symptomatic patients with severe AS valve gradient of greater than 50 mm Hg or valve area less than 0.8 cm ² /m ²

    • (2)

      Asymptomatic patients with significant stenosis and left ventricular hypertrophy should be considered who are undergoing CABG.

    • (3)

      Asymptomatic patients with evidence of decreased systolic function should also be considered.

  • e.

    Coronary angiography is performed before surgery because of high rate of concomitant coronary artery disease.

• 2.

  AI

  • a.

    Causative factors include rheumatic disease, annular ectasia, endocarditis, aortic dissection, and aortitis.

  • b.

    Frequently asymptomatic unless acute or decompensated

  • c.

    Acute AI presents with syncope, pulmonary edema, classic “water hammer” pulse, and Austin Flint murmur (late diastolic) from blood flow regurgitant jet hitting the anterior mitral valve leaflet.

  • d.

    Indications for surgery

    • (1)

      Symptomatic patients

    • (2)

      Patients with cardiomegaly or deteriorating systolic function as assessed by echocardiography asymptomatic; patients with severe AI and reduced systolic function less than 50% as assessed by echocardiography

    • (3)

      Asymptomatic patients and left ventricular diameter at end diastole (LVEDD) greater than 75 mm or left ventricular diameter at end systole (LVESD) greater than 55 mm

• 3.

  Mitral stenosis

  • a.

    Primarily rheumatic—leaflet thickening with calcification and fusion

  • b.

    Symptoms—dyspnea, orthopnea, and paroxysmal nocturnal dyspnea, atrial fibrillation. Loud S1, opening snap. Radiographs may demonstrate left atrial enlargement and pulmonary venous hypertension.

  • c.

    Indications for surgery—presence of chronic symptoms or acute episodes of pulmonary venous hypertension. Mitral valve area less than 1.5 cm ² and NYHA class III–IV symptoms

  • d.

    Chronic atrial fibrillation—a complication of progressive left atrial enlargement

• 4.

  Mitral regurgitation

  • a.

    Causative factors—rheumatic disease, myxomatous valve structure, endocarditis, ischemia or papillary muscle dysfunction, and congenital structural defects

  • b.

    Severity and development of symptoms—varies with causative factor; rheumatic disease is more insidious in onset, whereas ischemic mitral regurgitation is often acute in onset.

  • c.

    Carpentier classification

    • (1)

      Type I—normal leaflet motion: endocarditis, dilated cardiomyopathy with annular dilation

    • (2)

      Type II—excessive leaflet motion: prolapse, chordal rupture, papillary muscle rupture

    • (3)

      Type III—restricted leaflet motion

      • (a)

        IIIa: restricted opening: rheumatic disease

      • (b)

        IIIb: restricted closing: ischemic MR

  • d.

    As with mitral stenosis, indications for surgery depend on the severity of symptoms. Indications for surgery:

    • (1)

      Symptomatic severe MR and NYHA class II–IV LV dysfunction

    • (2)

      Asymptomatic severe MR with normal LV if repair greater than 90% likely, or new atrial fibrillation, or pulmonary artery pressure (PAP) greater than 50 mm Hg at rest

  • e.

    Ischemic mitral regurgitation is usually corrected at the time of coronary bypass, with either valve replacement or annuloplasty. Often mild ischemic mitral regurgitation may improve by coronary bypass only.

  • f.

    Rheumatic or myxomatous valve disease may be corrected by valve repair or replacement. The advantages of repair versus replacement are the low rate of endocarditis and lack of need for long-term anticoagulation. Mitral valve repair is associated with favorable outcomes over replacement.

C

Infective Endocarditis

• 1.

  Incidence 6.2 per 100,000 people per year

• 2.

  Etiology—indwelling catheters, IV drug use in the setting of damaged cardiac endothelium results in platelet and fibrin deposition and allows bacteria or fungus to adhere

• 3.

  Mitral > aortic > tricuspid (most common in IV drug users), may also have prosthetic valve endocarditis

• 4.

  Microbiology

  • a.

    Streptococcus viridans , Staphylococcus aureus , Staphylococcus epidermidis , enterococci

• 5.

  Clinical findings

  • a.

    Fevers, new murmur, Roth spots, Osler nodes, Janeway lesions, petechiae

• 6.

  Duke criteria

  • a.

    Major criteria (2): positive blood cultures ( S. viridans , Streptococcus bovis , HACEK [ Haemophilus species, Aggregatibacter species, Cardiobacterium hominis , Eikenella corrodens , and Kingella species], enteroccoci, S. aureus ), evidence for endocardial involvement on echocardiogram

  • b.

    Minor criteria (5): fever less than 38°C, vascular phenomena, immunologic phenomena, positive blood culture not previous meeting requirement, new-onset heart failure, new conduction disturbances, predisposing heart condition or IV drug use

• 7.

  Echocardiography—Transesophageal is 90% specific and 95% sensitive for detecting endocardial vegetations or lesions, versus transthoracic (90% specific and 50% sensitive).

• 8.

  Indications for surgery—new-onset heart failure, new heart block, continued sepsis despite optimal medical management, valve dehiscence, and fungal infection

D

Aortic Dissection

• 1.

  Causative factors—hypertension, atherosclerosis, connective tissue disorders, cystic medial necrosis (e.g., Marfan syndrome, Ehlers-Danlos, Turner syndrome), infections, trauma, pregnancy, age greater than 60 years are risk factors.

• 2.

  Clinical considerations

  • a.

    Dissections diagnosed within 2 weeks from onset of symptoms are acute.

  • b.

    Mortality secondary to acute dissection ranges from 30% to 40%.

  • c.

    Clinical presentation—sudden sharp tearing chest pain that radiates to the back; other symptoms can include stroke, MI, hemopericardium/tamponade, severe AI, renal/mesenteric ischemia, limb ischemia, paraplegia

• 3.

  DeBakey classification

  • a.

    Type I—intimal disruption of ascending aorta that extends to involve the entire descending thoracic aorta and abdominal aorta

  • b.

    Type II—involves the ascending aorta only (stops at the innominate artery)

  • c.

    Type III—involves the descending thoracic and abdominal aorta only (distal to left subclavian artery)

• 4.

  Stanford classification

  • a.

    Type A—any dissection that involves the ascending aorta

  • b.

    Type B—any dissection that involves only the descending aorta, distal to the left subclavian artery

• 5.

  Diagnosis is usually made by aortogram, chest computed tomography scan, or echocardiogram (transesophageal echocardiogram [TEE] or transthoracic echocardiogram [TTE]). Preoperative control of hypertension with nitroprusside and beta-blockers is an essential part of management.

• 6.

  Initial management

  • a.

    Start beta-blockade first to decrease heart rate and aortic wall d P /d t.

  • b.

    Nitroprusside can then decrease the blood pressure (if sodium nitroprusside [SNP] given first, it actually increases cardiac work and the d P /d t ; this theoretically can increase propagation of the dissection).

• 7.

  Dissection may advance proximally, disrupting coronary blood flow or inducing aortic valve incompetence, or distally, causing stroke, renal failure, paraplegia, or intestinal ischemia.

• 8.

  Indications for emergent operative repair

  • a.

    Acute type A dissection

    • (1)

      Operative repair involves replacement of the affected aorta with a prosthetic graft.

    • (2)

      Cardiopulmonary bypass is required, and hypothermic circulatory arrest is often used for transverse arch dissections.

    • (3)

      Aortic valve replacement (AVR) and coronary reimplantation may be required for type A aneurysms that involve the aortic root.

  • b.

    Type B dissection with failed medical therapy such as hypertension, inadequate pain control, progressive dissection by radiographic studies, impaired organ perfusion, or impending aortic rupture

    • (1)

      Type B dissections can be medically managed unless expansion, rupture, or compromise of branch arteries develops or hypertension becomes refractory.

• 9.

  Postoperative complications include renal failure, intestinal ischemia, stroke, and paraplegia.

E

Traumatic Aortic Disruption

• 1.

  This injury results from deceleration injury and usually occurs just distal to the left subclavian artery, at the level of the ligamentum arteriosum.

• 2.

  Chest radiograph findings include widened mediastinum, pleural capping, associated first and second rib fractures, loss of the aortic knob, hemothorax, deviation of the trachea or nasogastric tube, and associated thoracic injuries (scapular and clavicular fractures).

• 3.

  Definitive diagnosis is made by aortogram, but chest computed tomography and transesophageal echocardiography also aid in the diagnosis.

• 4.

  Imperative that immediate life-threatening injuries (e.g., positive diagnostic peritoneal lavage) be treated before repair.

F