Chapter 22: Cardiothoracic Surgery; Short Answer: Cardiac Surgery

What are the two types of valves used?

1) Biologic: wear out in 10-15 years and require replacement 2) Mechanical: tendency to form clots and requires anticoagulant therapy, can cause hemorrhage and endocarditis.

Describe an aneurysm, including the classifications.

A sac formed by localized dilation of the walls of an artery due to structural weakening. Aneurysms may be classified according to cause, shape, location, or structure. 1) Saccular 2) Fusiform 3) Dissecting 4) True 5) False

What is a cardiac tamponade? What treatment is necessary?

Compression of the heart by an accumulation of the fluid in the pericardial sac; Pericardiocentesis is the necessary treatment.

What are the higher risks for pediatric surgery? What additional precautions are used for pediatric surgery?

Hypothermia and blood loss. Warming blankets used, temperature closely monitored, blood loss closely monitored, sponges weighed and irrigation amounts measured accurately.

What is the surgical procedure to repair a mitral valve?

Mitral valve replacement.

What complications can occur from a myocardial infarction (MI)?

Myocardial rupture, cardiac aneurysm, heart failure, cariogenic shock.

How is the heart protected during CPB?

The body for the patient is cooled to 18 degrees to 20 degrees followed by circulatory arrest.

Describe how to assist the surgeon when passing prolene (polypropylene) suture.

Wet the surgeon's hands with saline when tying polypropylene sutures to prevent breaking them.

Describe how atherosclerosis forms.

A condition that involves the formation of an atheroma in the intima of medium and large arteries. The first step in the formation of the atheroma is believed to be an injury to the endothelial lining of the arterial wall. Blood platelets and lipoproteins are deposited into the injury as a repair mechanism, and growth factors released from the platelets stimulate the growth of new smooth muscle tissue in the arterial wall. Changes in the metabolism of the smooth muscle cells promote the acceleration of cholesterol and other lipids within the cells cytoplasm, which, when leaked across the cell membrane into the interstitial spaces, attract scavenger macrophages. The macrophages secrete biologically active substances that cause further damage to the arterial wall. Eventually, collagen is deposited into the lesion and scar tissue begins to form, narrowing the lumen of the artery.

How does a patent ductus arteriosus occur? How is it closed?

A failure of the fetal structure to completely close after birth. It is closed with surgical intervention.

What is a coarctation of the aorta?

A localized narrowing of the aorta in an otherwise normal vessel. Adult: distal to the left subclavian artery or ligamentum arteriosum. Infants: proximal to ductus arteriosus.

What is the difference between ASD and VSD?

ASD: Atrial Septal Defect. Abnormal opening in the wall between the two atria: ostium secundum, sinus venosus, and ostium primum VSD: Ventricular Septal Defect. An abnormal opening in the wall between the right and left ventricle.

Compare the CABG, MID-CAB, and OPCAB. Identify the major differences.

CABG: Coronary Artery Bypass Graft; Incision-> median sternotomy MID-CAB: Minimally Invasive Direct Coronary Artery Bypass Surgery; Incision 10cm OPCAB: Off-Pump CABG; Incision 20-30cm Both MID-CAB and OPCAB-> Do not require use of CPB machine.

What are the most common causes of aortic valvular disease (stenosis)?

Calcium build-up, birth defects, rheumatic fever, and radiation therapy.

What does CPB stand for? Describe the main components of the apparatus that is used for the procedure.

Cardiac Bypass Pump; Pump oxygenator, cannula, reservoir, heat exchanger, roller pumps, craniotomy suckers, blood filter, intracardiac vent.

What is the treatment for any of the cardiomyopathies? If the treatment is completed, what is the prognosis?

Cardiomyopathy: incurable; the best treatment is heart transplantation.

Describe the condition of cardiomyopathy, including the types of cardiomyopathy.

In response to injury, the heart often enlarges, restricting its normal functions; disease of myocardium/ Types: Alcoholic, congestive, hypertrophic, infiltrative, and restrictive cardiomyopathies.

Where are the primary cannulas placed?

In the right atrium or vena cava for draining venous blood to the pump oxygenator.

Describe how a rubber catheter tourniquet can be made.

Large red rubber catheters cut into 4" pieces are placed over each purse-string suture and the needles are cut off the suture ends.

Whom can the surgical technologist contact for information about any type of device, instrumentation, or equipment?

Literature provided by manufacturer, sales rep, and the surgeon.

If the cyanosis is severe, what can be done until the child is old enough to undergo full repair?

May require a shunt between aorta or subclavian and the pulmonary artery to increase blood flow to the lungs.

What is the purpose of an IABP?

Mechanical device designed for circulatory support after cardiac procedures which may increase cardiac output to a level that would permit separation from the pump oxygenator and allow time for the heart to recover.

What is (are) the cause(s) of mitral regurgitation?

Mitral valve prolapse, annular dilation of the posterior leaflet of the mitral valve.

What can occur due to stenotic valves?

Obstruction of the normal flow of blood from one region to another. Valvular insufficiency.

During open-heart surgery, a sternotomy is done. Analyze the sternotomy and repeat sternotomy, what is different for a repeat open-heart procedure?

On a repeat sternotomy, an oscillating saw is used so that a ventricle that may be adhered to the chest wall is not cut.

What tests confirm a diagnosis of myocardial infarction?

Presenting symptoms and evidence of impaired heart function that is found by physical examination, electrocardiography, and abnormal serum enzyme levels.

How is the tissue prosthesis prepared for use?

Room temperature saline should be used up to the point of aortic cross-clamping; thereafter, cold saline is to be used until the rewarming period. Warm saline should be used after rewarming begins.

What specialty equipment and medications are used to overcome some of the obstacles for the MID-CAB or OPCAB procedures?

Special loop suture and instrumentation has been developed to aid the surgeon in visualization and slowing down the heart. Meditronic OCTOPUS21 tissue stabilization system, Guidant Ultima OPCAB System, Heartport's OPTrac STILLSITE Stabilizer.

What can happen if the coarctation is not repaired?

Stroke, hypertension, ruptured aorta, and congestive heart failure.

What leads to a myocardial infarction?

Sudden occlusion of a narrowed vessel.

What can be used to repair the coarctation?

Surgical repair of the coarctation of the aorta.

What is the most common cyanotic heart defect in children? Describe the defect.

Tetralogy of fallout (ToF) is the most common VSD, infundibular or pulmonary valve stenosis, an aorta that overrides the VSD, right ventricular hypertrophy.

For a CABG, which vessels are used for the autografts?

The IMA (inferior meatal antrostomy) is used as a pedicle graft proximally from the level of the subclavian artery and distally to the costal margin.

Which anastomosis is made first, the distal or proximal?

The distal anastomosis is made first to the internal mammary artery or saphenous vein to the affected coronary artery.

What is used to prepare the IMA (internal mammary artery; If the left, then LIMA) for use?

The pedicle graft is soaked in papaverine solution for the prevention of vasospasm. A papaverine-soaked 4x4 gauze is usually wrapped around the graft.

Why are the vessels irrigated with heparin?

To ID any branches that may have been missed, vessels are stored in heparinized saline until needed.

What does VAD stand for? Why would it be used?

VAD = Ventricular Assistance Device; Serve as a temporary device that maintains circulation in patients who need a heart transplant. Temporarily support an open-heart patient who cannot yet be removed from the CPB.

What is used to repair the ventricular aneurysm defect?

Ventricular aneurysm repair.