Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Heart Valve Replacement


Related Terms

  • Aortic Valve Replacement
  • Heart Valve Prosthesis
  • Mitral Valve Replacement
  • Pulmonary Valve Replacement
  • Tricuspid Valve Replacement

Specialists

  • Cardiovascular Internist
  • Thoracic Surgeon

Comorbid Conditions

  • Bleeding disorders
  • Chronic obstructive pulmonary disorder (COPD)
  • Diabetes mellitus
  • Hypertension
  • Immunosuppression disease
  • Ischemic heart disease
  • Morbid obesity
  • Prior cardiac surgery
  • Renal insufficiency

Factors Influencing Duration

Factors that may influence the length of disability include the number and severity of postoperative complications (i.e., wound infection, bleeding, chronic musculoskeletal pain in the chest area, or an adverse reaction to a general anesthetic); the amount of blood loss during surgery and postoperatively; the number of blood transfusions required; the success of the valve replacement; the individual's nutritional status, mental and emotional stability, and access to rehabilitation facilities; and the strength of the individual's support system.

Medical Codes

ICD-9-CM:
35.2 - Open and Other Replacement of Heart Valve
35.20 - Open and Other Replacement of Unspecified Heart Valve; That with Tissue Graft or Prosthetic Implant
35.21 - Open and Other Replacement of Aortic Valve with Tissue Graft; Includes that by: Autograft, Heterograft, Homograft
35.22 - Open and Other Replacement of Aortic Valve; Replacement of Aortic Valve, NOS; That with Prosthetic (Partial) (Synthetic) (Total)
35.23 - Open and Other Replacement of Mitral Valve with Tissue Graft; Includes that by: Autograft, Heterograft, Homograft
35.24 - Open and Other Replacement of Mitral Valve; Replacement of Mitral Valve, NOS; That with Prosthetic (Partial) (Synthetic) (Total)
35.25 - Open and Other Replacement of Pulmonary Valve with Tissue Graft; Includes that by: Autograft, Heterograft, Homograft
35.26 - Open and Other Replacement of Pulmonary Valve; Replacement of Pulmonary Valve, NOS; That with Prosthetic (Partial) (Synthetic) (Total)
35.27 - Open and Other Replacement of Tricuspid Valve with Tissue Graft; Includes that by: Autograft, Heterograft, Homograft
35.28 - Open and Other Replacement of Tricuspid Valve; Replacement of Tricuspid Valve, NOS; That with Prosthetic (Partial) (Synthetic) (Total)

Overview

© Reed Group
Heart valve replacement refers to the replacement of a natural (native) heart valve with an artificial one (prosthetic valve). There are two types of prosthetic valves. The oldest type is composed of synthetic materials (mechanical valves), and the other comes from natural sources, either animal or human.

Natural valves are called tissue valves or bioprosthesis. Tissue valves are subclassified according to the tissue source. Heterograft valves or xenografts are taken from pigs (porcine) or cows (bovine). Homografts or allografts are valves removed from human cadavers. Autografts are live valves transferred from one position to another in the same individual. For example, an individual's aortic valve can be replaced with his or her pulmonic valve. The pulmonic valve is then replaced with a homograft valve.

Both types of prosthetic valves have their advantages. Mechanical valves have the advantage of lasting longer. The disadvantage is that the individual will need to take a blood thinner (anticoagulant) indefinitely. Conversely, tissue valves offer the advantage of not requiring anticoagulants and the disadvantage of being less durable. The type of prosthetic valve chosen for implantation depends primarily on the individual's age and willingness to take an anticoagulant indefinitely.

In general, individuals under age 60 receive mechanical valves because of durability and the reduced likelihood of needing a second operation later in life. They do, however, require lifelong anticoagulation therapy. Individuals over age 60 often receive tissue valves since durability is less of an issue.

Individuals with coronary artery disease or rheumatic heart disease or who have had rheumatic fever or bacterial endocarditis are at a higher risk for requiring heart valve replacement.

Source: Medical Disability Advisor



Reason for Procedure

The major reason for valve replacement surgery is to replace valves that are narrow (stenotic) or leaky (insufficient). These structural problems are due to either a congenital abnormality or acquired diseases such as rheumatic fever or atherosclerosis.

Source: Medical Disability Advisor



How Procedure is Performed

In the traditional surgical approach, the individual's skin and underlying tissue and muscle are cut (incised) from the notch at the top of the breastbone (sternum) to the bottom of the breastbone (xiphoid process). The breastbone is divided with an electric saw. A sternal retractor is inserted, separating the two sides of the split sternum and ribs and exposing the heart (median sternotomy). Alternative approaches include a partial midline incision in the upper third, middle third, or bottom third of the sternum as well as between the ribs and next to the sternum. The advantages include a better cosmetic result, less blood loss, a shorter hospital stay, and less pain medication.

The membrane covering the heart (pericardium) is incised and held back with lengths of surgical thread (suture). The individual is then placed on cardiopulmonary bypass (CPB). During CPB, the individual's blood flow is diverted from the heart and lungs through tubing connected to a heart-lung machine. Anticoagulants are added to the blood to prevent clots from forming on the tubing's artificial surface and traveling to the brain or other vital organs. As blood passes through the heart-lung machine, the pump oxygenator removes carbon dioxide and adds oxygen. The heart-lung machine then pumps the oxygenated blood back to the body through another set of tubing. This artificial circulation allows the cardiovascular surgeon to work in a nearly motionless and bloodless surgical field without endangering the flow of blood and oxygen to the individual's vital organs and other tissue. Under these optimal conditions, the surgeon cuts away (excises) the diseased heart valve and sutures a replacement valve into position.

Because the heart and lungs receive no blood or oxygen (and other vital organs receive a reduced amount of oxygen) while the individual is on CPB, measures need to be taken to reduce the body's need for oxygen by reducing body temperature. This is accomplished with the heat exchanger portion of the heart-lung machine. Cooling the body's temperature to approximately 82° F (27.7° C) reduces its need for oxygen by 50%. Cooling the body's temperature to 68° F (20° C) reduces the body's need for oxygen another 25%.

When the surgeon has completed the surgical repair, the individual's body is warmed the same way it was cooled. The sternum is closed with metal wires and the skin sutured closed.

Source: Medical Disability Advisor



Prognosis

The operative mortality rate for mitral valve replacement is about 2% to 7%, and the overall survival rate is 82% at 1 year, 68% at 5 years, and 55% at 10 years (Kouchoukos, "Mitral Valve Disease"). The operative mortality rate for aortic valve replacement is 3.4%; if coronary artery bypass grafting is done at the same time, the mortality rate rises to 6.3%. The overall survival at 5 years is around 75%; at 10 years, 60%; and at 15 years, 40% (Kouchoukos, "Aortic Valve Disease").

A given individual's risk of death within 10 years after surgery is related to the individual's age at the time of surgery, overall function of the heart, presence of atrial fibrillation, durability of the valve, and need for anticoagulant therapy.

The rate of success for heart valve replacement surgery is high and increasing. Individuals who recover from this procedure usually lead normal lives with relatively few symptoms of chronic heart disease.

Source: Medical Disability Advisor



Rehabilitation

Respiratory therapy begins in the intensive care unit as soon as the breathing tube (endotracheal tube) is removed. Respiratory therapy focuses on preventing the buildup of lung secretions that can lead to pneumonia and re-inflating the lungs to their presurgical condition. Respiratory therapists teach individuals techniques to increase airflow and use incentive devices to encourage deep breathing and effective cough techniques.

Cardiac rehabilitation begins in the hospital shortly after the immediate postoperative period and focuses on helping individuals resume a more normal lifestyle following surgery. Phase 1 often begins in the hospital with low levels of exercise to help prevent the hazards of bed rest, reduce episodes of low blood pressure when changing positions (orthostatic hypotension), and maintain overall mobility of the body. Intensity gradually increases until discharge from the hospital.

Phase 2 usually begins after discharge from the hospital. Individuals not hospitalized typically begin rehabilitation at this phase, which is done in a cardiac rehabilitation center. The goals are to improve the individual's functional capacity by increasing physical endurance, promoting return to activity, providing education about lifestyle changes, reducing fear and anxiety, and helping the individual make good social and psychological adjustments following surgery.

Individuals are usually attached to an electrocardiograph (ECG) monitor, and a physical therapist keeps a daily log of the individual's blood pressure, heart rate, and cardiac rhythm. Individuals perform aerobic exercise, such as treadmill walking or stationary bicycling. Aerobic exercise helps the heart muscle improve efficiency of oxygen use, reducing the need for the heart to pump as much blood. The improved fitness level reduces the total workload of the heart and increases endurance, enabling individuals to return to their prior activity levels. The program is modified as needed for each individual.

Phase 3 continues in an outpatient setting with gradually increasing levels of exercise and the addition of more physically demanding exercises. The goal is to increase aerobic activity in a stepwise fashion to promote cardiovascular endurance and strength so the individual may return to work or resume prior activity levels. For the rest of their lives, these individuals need to take antibiotics before undergoing any dental work or surgery to prevent bacterial endocarditis.

Source: Medical Disability Advisor



Complications

Operative complications common to both types of valves include bleeding, arrhythmias, infection, dehiscence of the sternum, thrombophlebitis, pulmonary emboli, stroke, acute myocardial infarction, and respiratory and kidney failure.

The major complication of tissue valves over time is degeneration that requires a second operation. The major complications of mechanical valves are related to the need for anticoagulant therapy to prevent clot (thrombus) formation in the valve. Pieces of thrombus (emboli) may break off and lodge in any organ, resulting in serious consequences such as a stroke. Long-term complications common to both types of valves include bacterial endocarditis and paravalvular leaks.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

After six postoperative weeks, individuals who have had successful heart valve replacement surgery without experiencing serious postoperative complications or disabilities can usually return to work part-time, with few if any restrictions on activity with the exception of heavy lifting. Hours of work may be gradually increased over the next 6 to 8 weeks until the individual is working a full shift.

Individuals with residual chronic heart disease or chest pain may need reassignment to tasks that demand less energy and are less cardiac-intensive. Other medical problems or permanent disabilities caused by underlying medical conditions (i.e., diabetes, chronic obstructive lung disease, or chronic renal failure requiring dialysis) or postoperative complications (i.e., partial paralysis or speech impairment because of stroke) may also require continued work restrictions and accommodations.

Source: Medical Disability Advisor



References

Cited

Kouchoukos, Nicholas, et al., eds. "Aortic Valve Disease." Kirklin/Barratt-Boyes Cardiac Surgery. 3rd ed. 2 vols. Philadelphia: Churchill Livingstone, Inc., 2003.

Kouchoukos, Nicholas, et al., eds. "Mitral Valve Disease With or Without Tricuspid Valve Disease." Kirklin/Barratt-Boyes Cardiac Surgery. 3rd ed. 2 vols. Philadelphia: Churchill Livingstone, Inc., 2003.

Source: Medical Disability Advisor






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