VALVULAR CARDIAC SURGERY



VALVULAR CARDIAC SURGERY

• Anatomy and Physiology

← Normal Circulation

← Blood returns via superior and inferior vena cava entering into the right atrium

← Passes through the tricuspid valve into the right ventricle, then through the pulmonic valve into the pulmonary artery

← Reoxygenated in the lungs and returns via the pulmonic veins into the left atrium

← Passes through the mitral valve into the left ventricle, then through the aortic valve into the coronary ostia and via aorta to the rest of the body.

← Cardiac Valves

• Tricuspid valve lies between right atrium & right ventricle; “three-cusped”

• Mitral valve lies between left atrium & left ventricle; “two-cusped” or bicuspid

The mitral and tricuspid are often referred to as atrioventricular valves, as they separate the atria and ventricles.

← Leaflets are attached and anchored to the endocardial papillary muscles by cords called cordae tendineae, which keep the valve from prolapsing

• Aortic valve lies between the aorta and the left ventricle

• Pulmonic valve lies between the pulmonary trunk and the right ventricle

The aortic and pulmonic are often referred to as semi-lunar, meaning they have three half moon shaped cusps

← Cardiac Conduction

• Coordinates cardiac contraction

← SA Node (sinoatrial) “the pacemaker”

← AV Node (atrioventricular)

← Bundle of HIS or AV Bundle -- in ventricular septum; insulated

← Purkinje Fibers -- non-insulated and feed into R/L ventricles

• SA node initiates impulse > atria contract (blood forced into ventricles)> stimulus picked up by AV node > AV Bundle (signal slightly delayed) > brnached bundles > purkinge fibers > ventricles stimulated and contract (blood forces atrioventricular valves to close and semilunar valves to open) -- These valves should go one-way

• Pathology of Valves

• Obstruction of valves is usually caused by stenosis or fusion of leaflets. Reduced blood flow causes poor oxygenation or backup of blood into the respective ventricles

• Backup damages the ventricular endocardium and myocardium over time, which can cause ventricular aneurysm (thinning and enlargement of the ventricle)

• Valves can be regurgitant or insufficient due to leaflet damage

• In the case of the mitral valve, damage can be to the cordae tendineae, causing elongation, rupture, or shortening

← Aortic Stenosis

← Calcification of the aortic valve cusps

← LV hypertrophy develops as result of restricted blood flow into the aorta

← Sx: fatigue, DOE, palpitations, dizziness, fainting, angina (chest pain)

← Pulmonic Stenosis

← Calcification of pulmonic valve cusps

← Restricts flow into PA

← RV hypertrophy

← Mitral Regurgitation

← Blood flows back (regurgitates) into the RA through the incompetent mitral valve

← LV hypertrophy

← Sx: fatigue, palpitaion, orthopnea (need to sit up to breath), PND (paroxysmal nocturnal dyspnea, after sleeping wakes up needing air)

← Mitral Stenosis

← Calcified mitral valve

← Impedes flow of blood into LV

← LA hypertrophy or enlargement

← Sx: fatigue, palpitations, DOE, orthopnea, PND, pulmonary edema

← Tricuspid Regurgitation

← Blood flows back (regurgitates) into RA due to incompetent tricuspid valve

← Sx: engorged pulsating neck veins, liver enlargement, RV hypertrophy, thrill at left sternum

← Tricuspid Stenosis

← Calcification of tricuspid valve

← Impedes blood flow into RV

← Sx: diminished arterial pulse, jugular venous prominence

← Valvular Disease

• Causes:

← CAD and MI

← IV Drug Abuse

← Dental Infections

← Lupus

← Marfan’s Syndrome

← Scleroderma

← Degenerative (age)

← Congenital disease

← Rheumatic heart disease (a complication of bacterial strep) primary cause

← Obstruction results in left ventricular myocardial overload due to backflow of blood, which stresses the myocardium over time

• Symptoms: fatigue, weakness, dyspnea (with or without exertion, stress, or pregnancy), pulmonary edema

• May go from mild to total disability in 5- 10 years

• May be asymptomatic 10-20 years after initial damage to valve

← Diagnosis

• noninvasive

← H & P

← ECG/EKG

← Exercise EKG (stress test)

← Echocardiogram (echocardiography is the Gold Standard for diagnosing valvular disease)

← Chest x-ray

• invasive

← Cardiac catheterization ( may be in conjunction with echocardiogram)

← Trans-esophageal echocardiogram (usually done preoperatively in the OR suite in conjunction with valve surgery)

• Valve Procedures

← Anesthesia

← General

← Medications

← Warm saline with antibiotic solution

← Topical hemostatic agents of choice: surgicel, gelfoam and thrombin, gelfoam/thrombin/antibiotic rolled into balls for sternal bone application, bone wax for sternum with raytex underneath to prevent surgeon from ripping gloves on rough edges

← Extra NS for valve rinsing if is a xenograft (Will rinse x 3 in 250cc NS each rinse for 2 minutes each or per manufacturer’s recommendations; some surgeons may want antibiotic added to 2nd or 3rd rinse)

← Patient Positioning

← Supine position

← Arms padded and tucked

← May want a shoulder roll to elevate the sternum (optional)

← Headrest

← Pillow under knees (preferable)

← Heel pads (preferable)

← Prep

← Begin at anterior thorax prepping outward in a circular motion to the bedline, prep to top of thighs/ bilateral groins, then pubis

← With a separate sponge prep both legs to knees to the bedline

← Use betadine soap, then paint -- minimum 2 coats of paint -- may use gel or spray

← For a CABG & valve replacement, prep sternum to neck, bedline to bedline, groin, pubis, then each leg circumferentially to ankles or feet (institutional policy)

← Equipment

← Mayo stand (for saw)

← Double ring

← Prep tables x 2

← Slush machine/warmer

← ECU x 2

← Cell saver

← CPB machine

← Off-table suction

← External Pacing box

← Two large tables (back table and Mayfield

← Instrumentation

← Open heart Trays

← Valve Tray

← Suture Guide Holder

← Sternal saw

← Internal defibrillator paddles

← Doctor’s specials

← Micro instruments needed if CABG done with valve surgery

← Sternal retractor (Ankinney for aortic valve) and (Cosgrove or Korous for mitral or tricuspid); Finochetti

← Supplies

← Valve Custom Pack

← (Coronary Pk if CABG/Valve

← CV Drape Pack

← Gloves

← Chest tubes

← Suture guide inserts

← Valve Sizers

← Appropriate valves

← Aortic cannula

← Retrograde cannula

← Medusa

← Cardiac insulation pad

← Myocardial temp probe

← Three cytals for washing valve if using a xenograft (porcine or bovine)

← Coronary ostia perfusion catheters (auto-inflating, gummy tip, or spencers (for aortic only))

← Venous cannula (need two for bicaval cannulation-need for mitral valve surgery)

← Antegrade cannula (may just use retrograde and place this after aorta closed for aortic valve surgery/is placed for mitral valve surgery)

← Misc. suture: pericardial suture, cannulation suture, aortic retraction suture (for aortic valve only), valve repair or replacement suture, suture to close aorta or atrium, pacing wires, suture to sew in pacing wires, cutting needles to sew in chest tubes and pacing wires, sternal wires, fascia suture, subcutaneous, subcuticular

← Valve Replacement Options : diseased valve excised and replaced

• Mechanical (Aortic, mitral)

← St. Jude or Starr-Edwards

← valve only

← conduit/valve available for aortic

← Durable

← Used primarily in young patients

← Patient requires long-term anticoagulant therapy (not for elderly)

← Complications: emboli and bleeding from other injury due to anticoagulant therapy

• Biological :

• Heterograft/Xenograft (aortic, mitral)

← May be bovine or porcine

← Old porcine has a duration of 15 years

← Bovine pericardium is the new rage; thought to last longer but not certain yet

← No anticoagulant therapy needed

• Aortic Stentless (Aortic)

← Porcine

← Durability good over age of 60

← No anticoagulant therapy needed

• Allograft/Homograft (Aortic, Mitral, Pulmonic)

← Cadaver from organ donor

← Will measure annulus size with TEE

← Will choose graft before incision made or as opening chest

← Time will be required for proper thawing procedure to be implemented to prevent damage to the graft

← Long term

← Limited availability

• Autograft (ROSS Procedure) (Aortic)

← Requires expert valve surgeon

← Excision of patient’s pulmonic valve to be used as the patient’s new aortic valve

← A pulmonic allograft will be used to replace excised pulmonic valve

← Long term

← Limited availability of pulmonic allograft

← Valve Repair Options

• Replacement verses Repair

← Aortic and Mitral are replaced

← Tricuspid in extreme situations can be replaced with a mitral valve

← Mitral and tricuspid usually repaired with annuloplasty rings

← Mitral may have to be replaced if attempted repair is unsuccessful

• Annuloplasty rings provide reduction of the dilated annulus

← Used for repairing of the mitral or tricuspid valves

← Mitral rings are a near to complete circle

← Tricuspid rings are an incomplete circle or half-circle

← Often the tricuspid function will return to normal with the repair of the mitral

← Sizers are half moon shaped and have T or M on them (will come with a malleable handle-bend it slightly for ease of sizing) Are differentiated between by T or M on the tag (remove the Minnie-Pearl tag before passing it to the surgeon)

•

← Valve Repair/Replacement Procedure

← Getting in

← Incision with #10 blade, cautery

← Curved mayo scissors to loosen fascia under xiphoid process (optional)

← Sternal saw >> bone wax or gelfoam powder mixed with saline or thrombin to make soft balls to spread on sternum >> wet laps folded in half (should have been soaked in antibiotic NS and wrung out) >> sternal retractor

← Cautery and debakeys to open/dissect the pericardium

← Pericardial sutures (may use pop-off silk or neurolon)

← Dissect aorta from pulmonary artery to provide room to place aortic cross-clamp

← Purse-string cannulation stitches for aortic cannula (x2), venous cannula, and retrograde cannula, each is rommeled

← Heparin is administered by anesthesia at surgeon prompt and place cannulas:

← Aortic: stab blade (#11), aortic cannula, heavy tie or umbilical tape, tube clamp, bowl and scissors to cut aortic pump line, hook to CPB tubing, make sew cannula to patient/drape or clamp with non-penetrating towel clip

← Venous: metz, cannula (some surgeons may use a satinsky to clamp the atrial appendage before incising it), heavy tie or umbilical tape, tube clamp or not and hook to venous line from CPB machine

← Surgeon will say to perfusion, “Go on bypass” -- Perfusionists will cool blood

← Cross Clamp will be placed across the aorta

← Cardiac insulation pad may be placed

← Myocardial temp probe may be placed near the apex of the left ventricle

← Ice may be applied to the heart as well

← Aortic Valve Replacement access

← Once temperature is where surgeon wants it, he will take a metz and cut the aorta open above the aortic valve and below the aortic cross clamp

← May want stay sutures or retraction sutures

← May continue to perfuse the heart with cardioplegia fluid directly into the coronary ostia via the medusa and coronary perfusion cannula that is attached

← Will excise the valve using metz, a pituitary ronguer, knife (#15c or #11) -- be prepared to wipe ronguer , metz, and forceps frequently with a moist lap

← Retraction may be provided by the assistant with a hand-held aortic retractor

← Off-table suction to “vacuum” removed plaque (tonsil suction without tip) -- Care is taken NOT to get debris into the ventricle as it could cause stroke later

← Cold NS Irrigation provides thorough cleaning using an asepto

← Mitral Valve Repair/Replacement access

← Caval tapes will be used with a ligature passer or right angle and long dacron or polyester tapes and rommeled to provide a tight seal around the cavae and their cannuli to prevent blood from coming into the field around the cannuli

← Heart is turned over and left atrium is exposed

← #11 or #15 blade to open the atrium, long metz to widen the incision

← Hand-held mitral/atrial retractor, or cosgrove or korous retractor

← Two long, blunt nerve hooks will be passed to the surgeon for him to manipulate the valve leaflets and determine location/extent of damage

← Will repair by removing a leaflet, repairing the cordae tendineae with gortex (PTFE) or prolene suture (have knife, metz, and nerve hooks available)

← One of the leaflets may be left to maintain ventricular configuration (if one passed to you, ask if it is the anterior or posterior for proper specimen labeling)

← Replacement of valve

← (Be sure you keep up with how many sutures are used)

← Once valve annulus is clean, annulus is sized with appropriate sizer

← Valve is passed to field after being verified by the circulator, scrub, and surgeon

← Bovine and porcine valves require a rinsing process (2 minutes in a minimum of 250ml NS times three); Baxter-Edwards only require one minute x 3

← Sutures for valve are placed (pledgeted 2-0 RB-1 ethibond or CV-316 Ticron

← Pledgeted sutures are used for valve replacement/Non-pledgeted for repair

← Sutures will be passed double loaded as all pledgeted sutures should

← Once sutures are in, if valve is ready, three short NH will be passed up and the assistant, scrub, PA, and surgeon will work their way around the suture guide loading each needle in sequence for the surgeon to pass through the valve

← The sutures should have been counted before valve is up so the surgeon knows how far apart to place the sutures in the cuff of the valve

← After sutures are in surgeon will ask for 2 kellys and you or he will cut the needles

← He will pass them to you attached to the other kelly

← He will work the valve into the annulus of the excised valve (you should moisten the strings with NS as he seats the valve)

← He may take a knife to release the insert holding the valve to the handle

← He will work his way around, tying in the interrupted sutures

← Will use long tenotomy scissors to cut the strands just above the knots

← Will test the valve leaflets with NS in an asepto (may use several) --may use short pc of red-rubber catheter attached to asepto for visibility

← If mechanical may use rubber shodded debakey forceps or long cotton-tip applicator to test leaflets

← Will close aorta with 2 prolene sutures usually pledgeted with a corresponding on a 3-0 or 4-0 tapered RB-1 or SH needle

← Will close atrium with a 4-0 or 3-0 prolene on a tapered SH or MH needle (usually non-pledgeted)

← Air is vented via antegrade placement (if was not in-aortic) -- may need 14 jelco on 60 cc syringe to stab apex/ventricle to remove air before discontinuing bypass

← Topical hemostatic may be used (gelfoam pad strips with NS or thrombin)

← Patient may need to be defibrillated (have ready when closing aorta or atrium)

← CPB will be discontinued when patient is re-warmed (metz, tube clamps, metz)

← Pacing wires will be placed (atrial and ventricular)

← Chest tubes will be placed (1 mediastinal and 1 substernal)

← Sternal wires placed twisted and cut with wire cutter, irrigation of NS with Antibx, fascial layer, subcutaneous, hook up pleurevac after suctioning out the chest tubes, subcuticular

← Dressing, steri-strips, telfa, 4x4s, primapore; Fluffs or 4x4s to chest tubes and tape

← Complications

← Hypothermia

← Infection

← Myocardial contusion

← Bleeding

← Cardiac tamponade

← Embolus

← Valve malfunction

← Ventricular Aneurysm Repair or Ventricular Aneurysmectomy = DOR Procedure

• Result of myocardial damage after an MI causing myocardial replacement with scar tissue; Scar stretches with pressure, resulting in aneurysm formation

• Is the excision of the portion of the ventricle that has become aneurysmic and re-enforcing it with a patch of synthetic graft material (may be PTFE or hemashield) Often a tube graft is used and a circular patch is cut with it

• Usually done with CABG or Valve surgery; may require CPB

• Prep/Set up is as above though if done alone, will need less items

• Procedure:

← Incision made into the ventricle with a #15 or #11 blade extended with a metz

← Ass’t retracts with two allises or babcocks – usually incl in valve tray

← Surgeon may remove or excise a part of the scar tissue

← A neck will be created in the rim of the scarring with a prolene suture (2-0 or 3-0 on an SH, to pull the tissue back together)

← Interrupted pledgeted ticron or ethibond sutures will be placed (2-0 RB-1 or CV-316, SH or CV-305)

← Patch will be passed up with 2 NH to place sutures through the patch

← Patch will be eased down to cover the created neck

← Myocardium will be closed with another 3-0 prolene SH

← Epicardium will be closed with two thinly cut strips of teflon felt and two running 3-0 or 2-0 Prolene sutures on an SH or MH tapered needle

← Patient rewarming if was cooled and discontinuation of CPB (if it was used)

← Routine open heart surgery closure

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