21 Mar 2019

AMA Guides Fifth Edition and the Heart: A California Perspective

By Hon. Robert G. Rassp

The opinions expressed in this article are those of the individual author and are not those of the California Department of Industrial Relations, Division of Workers’ Compensation or of the WCAB.

The following is a quick reference of common medical conditions that are found in AMA Guides Chapter 3: The Cardiovascular System: Heart and Aorta, and Chapter 4: The Cardiovascular System: Systemic and Pulmonary Arteries. There are some notes in parentheses that indicate a condition may be indirectly work related in certain circumstances. Caution: Many medical conditions can result in impairments that are discussed in multiple chapters of the AMA Guides.

AMA GUIDES CHAPTER 3: THE CARDIOVASCULAR SYSTEM: HEART AND AORTA

  • HEART
  • ARRYTHMIAS (e.g., ATRIAL FIBRILLATION)
  • MYOCARDIAL INFARCTIONS (HEART ATTACKS)
  • CORONARY ARTERY DISEASE
  • CORONARY BY-PASS SURGERY
  • MITRAL, TRICUSPID, AORTIC, PULMONARY VALVE DISORDERS
  • CARDIOMYOPATHIES

AMA GUIDES CHAPTER 4: THE CARDIOVASCULAR SYSTEM: SYSTEMIC AND PULMONARY ARTERIES

  • HYPERTENSION
  • ANEURYSMS
  • THROMBOPHLEBITIS
  • PULMONARY EMBOLISMS
  • LEFT VENTRICULAR HYPERTROPHY (LVH)
  • DEEP VEIN THROMBOSIS (DVT)
  • RAYNAUD’S PHENOMENON

HEART DISEASE: AMA GUIDES, CHAPTER 3

AMA Guides Chapters 3 (heart/aorta) and 4 (cardiovascular system) are discussed together in this section. The AMA Guides use the nationally recognized New York Heart Association (NYHA) Functional Classifications of Cardiac Disease that are also used in Social Security disability cases. See Table 3-1 on page 26 that divides cardiac conditions into four classes (Class I through Class IV). The determination of which class of cardiac disease a patient has depends upon the METs and treadmill results listed in Tables 3-2 and 3-3 on page 27, plus the effect of the cardiac disorder on the patient’s ADLs in Table 1-2 on page 4.

Do not confuse an NYHA classification for heart disease from an impairment Class described in the Tables and Figures in Chapter 3 of the AMA Guides. Most physicians who rate heart disease for WPI in workers’ compensation cases do not pay much attention to the NYHA classification for heart disease; at least they rarely mention it in their reports. What is more important is the type of heart disease, the Class of impairment from the appropriate Table and the WPI rating within the Class.

METS (metabolic equivalent of tasks) means a multiple of metabolic energy while at rest and is used to assist a physician in determining cardiac disease functional class based on exercise tolerance and cardiac symptoms. One “MET” is the amount of energy a person expends while at rest that includes all of the autonomic activities such as breathing, brain work and basic movement we do while we are at rest. So a man who weighs 154 lbs with a MET of 1.0 expends 1.2 kcal/minute. One calorie is the amount of energy needed to raise the temperature of one cubic centimeter of water one degree centigrade. He would expend 3 METS when walking about 2.7 miles per hour. A person who can exert 5.0 METS can perform an 18-hole round of golf or can walk 3–4 miles per hour for 20 minutes. A person with a METS of 7.0 can run 4–5 miles per hour for 20 minutes.

So when you look at Table 3-2 on page 27 and you walk briskly or you regularly use a treadmill, you want to be within a METS of 10 through 16. Most physicians consider a METS of 10 or greater “normal” cardiac function. A METS of 7 or less means there is probably at least NYHA functional class II cardiac disease. Most cardiologists use the 12 minute Bruce Protocol treadmill testing that is listed in Table 3-2 where you start at 1.7 mile per hour at a 10% grade (steepness or incline of the treadmill) and every three minutes for a total test time of 12 minutes, the speed and incline of the treadmill increases with a maximum speed of 4.2 miles per hour at a 16% grade. If you have never had a treadmill test, you will see how much work it is to walk 4.2 mph at a 16% grade for three minutes if you have a sedentary lifestyle. You would appreciate anyone with heart disease trying to do this, which is why the Bruce protocol is widely used in California and throughout the nation. Under the Bruce protocol, a person has a NYHA Class I cardiac condition if exertion is > 6 minutes and has to stop before 12 minutes; Class II if exertion is 3–6 minutes; Class III if 1 to 2 minutes; and Class IV is

A cardiologist or internist can always tell when a patient is lying about his or her being in good physical condition. The first question that is answered during a stress treadmill using the Bruce protocol is when does a patient hit 90% of his or her maximum heart rate during the 12 minute treadmill test? Your maximum heart rate is 224 minus your age times 90% [(224 – age) x .90]. If a patient hits 90% of their predicted maximum heart rate in 3 minutes of a 12 minute Bruce protocol, it means he or she is probably a couch potato or has serious heart trouble. The second question is how long does it take for the patient to reach 100 beats per minute (bpm) after reaching 90% of the predicted maximum heart rate? The recovery to under 100 bpm should occur in less than 2 minutes post-exercise treadmill. So a 60-year-old man’s maximum predicted heart rate would be 148 bpm [224 − 60 = 164 × .90 = 147.6 = 148 bpm. An athlete would hit 90% of his or her maximum heart rate after 12 minutes under the Bruce protocol. This is why there are other nationally accepted stress treadmill tests that you can see on Table 3-2 on page 27 of the AMA Guides. The Bruce protocol still remains the gold standard for most patients to determine heart health.

In addition, an ECG or electro-cardiogram during a stress treadmill test can determine the existence of any arrhythmias as well as potential life-threatening cardiac conditions including coronary artery disease.

You can have a case in which the injured worker has more than one ratable cardiac condition. A person could have coronary heart disease (Table 3-6a, page 36), an arrhythmia such as atrial fibrillation (Table 3-11, page 56) and cardiomyopathy (Table 3-9, page 47). These would be ratable separately and combined. In fact, a recent case involves a probation officer who has prolonged QT syndrome (an arrhythmia) with hypertensive cardiovascular disease (Chapter 4, Table 4-2, page 66) and had to have both an implanted cardiac defibrillator and a pacemaker. Each condition has a separate Class and WPI rating within a class and then those WPI ratings are combined using the Combined Values Chart.

Page 28 of the AMA Guides describes specific aspects of heart function that are still relevant over 18 years after the 5th Edition was published. Any test of functional capacity from a cardiac standpoint is sensitive to outside factors such as age (e.g., a 20-year-old athlete vs. a 70-year-old sedentary woman), gender, and level of exercise training. Left ventricular function is extremely important to evaluate any heart impairment. Left ventricular function has two components—systolic function which the amount of blood that is pushed out into the aorta by each heart beat and diastolic function which is how much the heart muscle relaxes between beats in order to fill with blood.

Systolic function is measured by one’s ejection fraction (EF) which is the percentage of blood the heart is able to eject during one heartbeat. Normal EF is anything >0.50. EFs 0.40 to 0.50 indicate mild systolic dysfunction; EFs 0.30 to 0.40 indicates moderate systolic dysfunction, and an EF

When you review a workers’ compensation claim that involves the heart, you must pay very close attention to the laboratory results from an initial hospitalization by a treating physician and the tests an AME or PQME orders at the time of an MMI examination. Positive troponin blood tests in medical records when a person was hospitalized with an alleged heart attack confirm damage to the heart muscle and confirms the existence of a myocardial infarction. This fact alone places a patient into a Class 2, 3, or 4 cardiac impairment rating. Also at the time of an MMI examination, evidence of hypokinesis from a cardiac ultrasound test demonstrates permanent damage to the heart muscle. Hypokinesis means that the heart muscle is not contracting properly due to damage to an area of heart muscle where a heart attack had occurred. This could and does affect a patient’s ejection fraction and systolic pressure. Also, abnormal liver function or kidney function can also have a cardiac origin, especially as a result of major organ shut-down during open heart surgery, insufficient cardiac output, or as a result of a heart attack. Counsel should always ask a treating or evaluating physician about any laboratory abnormalities that exist at the time of an MMI examination. Liver and kidney abnormalities that result in permanent impairment are separately rated from the ratable cardiac impairments.

As stated above, there is a direct link between a patient who has diastolic dysfunction and congestive heart failure (CHF). Congestive heart failure occurs when the heart is unable to pump enough blood to flow into the body. The signs and symptoms include the build-up of fluid (edema) in the lower extremities with swelling in the ankles and legs and severe shortness of breath. Usually the treatment begins with a “water pill” or diuretic such as Lasix but that therapy is only temporary and the concern is to find the cause of the CHF if possible and to directly treat the cause of it. Any patient who develops CHF will automatically fall into a Class 4, 50% to 100% WPI rating for the various heart conditions in AMA Guides Chapter 3. These are seriously ill patients who need intensive and immediate treatment and who rarely have a good outcome.

A “normal” person has the following normal cardiac profile:

  1. Cardiovascular system has normal measurements on standard protocol ECG and other testing;
  2. Person can perform all activities of daily living without cardiac symptoms;
  3. Person has cardiac reserve capacity that allows comfortable exercise without the development of major cardiovascular symptoms;
  4. Person has normal left ventricular ejection fraction (i.e. >0.50);
  5. Person is able to complete at least 80% of age and gender predicted functional aerobic activities during exercise stress testing.

As a side note for anyone who reads this part of the guidebook, if you are over 40 years of age, you should have a base-line ECG, cardiac Doppler study and exercise treadmill test. This is good preventative medicine and can assist you as you age with repeat testing every year or two.

Tables 3-5 through 3-11 on pages 30, 36, 38, 42, 47, 52, and 56, respectively, use the NYHA classification system on a disease specific basis. Tables 3-6a and 3-6b on page 36 are the most notable for workers’ compensation purposes because they include four classes of whole person impairments for coronary heart disease. Note the range within each of the four classes, especially Class 4 with a range of 50% WPI to 100% WPI.

Whole person impairments for cardiac arrhythmias are listed in Class 1 through Class 4 in Table 3-11 on page 56 with the same ranges of variance within each class as for coronary heart disease. Table 3-12 is a helpful chart on page 60 that summarizes the cardiac impairments in AMA Guides Chapter 3 and refers you to the proper section and tables to determine impairments under those classes of cardiac disorders.

Make sure a treating or evaluating physician correctly classifies a person’s cardiac disease using the NYHA criteria listed in AMA Guides Table 3-1, page 26. The person’s cardiac condition must be matched to both the proper NYHA classification in Table 3-1 and to the appropriate impairment rating for the actual cardiac diagnosis in the other tables in Chapter 3. For a person who has a heart attack and coronary by-pass surgery, the impairment rating would be found in AMA Guides Tables 3-6a and 3-6b, page 36. For a person who has developed an arrhythmia, the impairment rating would be found in Table 3-11, page 56. Development of the medical-legal record should cause counsel to focus upon the selected NYHA classification in a case first and then an evaluation of the impairment rating using the appropriate table, class, and rating within a class, including how a physician determined each conclusion. This is especially true because in practice, we are seeing some physicians skirt the NYHA classification in most cases as stated above.

In virtually all workers’ compensation cases that involve the heart, it is strongly recommended that you read each example in the AMA Guides Chapter 3 to see if a given case is similar to any of the examples. This will assist you in preparing to cross examine an evaluating or treating physician on a WPI rating with which you disagree. Since there are no guidelines for how ADLs are affected in each Class of impairments in all tables in Chapter 3, your knowledge of an accurate history and current complaints of the injured worker are essential, along with the types and number of medications the injured worker has been prescribed. All of these factors, along with the permanent objective medical findings for each class of impairment, must exist in order to obtain the most accurate rating for heart disease.

Counsel needs to become familiar with the diagnostic criteria for heart diseases including coronary heart disease, valvular heart disease, congenital heart disease, cardiomyopathies, pericardial heart disease, and arrhythmias. All of these disorders of the heart are ratable, and the AMA Guides have specific tables and figures for them.

In addition, since these cardiac disorders require significant medications for treatment, counsel should also be aware of potential side effects of some medications that may cause independent ratable factors of impairment, especially anti-coagulant medications.

The most common heart condition we see in our cases involves coronary heart disease, or more accurately coronary artery disease (CAD). This involves clogging of the arteries, or more formally, due to arteriosclerosis and narrowing of the coronary arteries. Blood flow is restricted and the person is of high risk of a piece of the plaque to flow off and cause a total occlusion of an artery causing a heart attack or myocardial infarction. When there is reduced blood flow due to stenotic (narrowed) arteries, the heart pumps harder in order to pump the blood through the body. Imagine yourself using a 5-pound dumbbell for one hour a day for one year with your left hand and arm doing curls and not using the right hand or arm at all. In one year if you measure the circumference of your biceps muscle, your left side will be quite larger than the right biceps circumference. The same thing is happening to people who have left ventricular hypertrophy (LVH)—an enlarged left lower chamber of the heart becomes that way because of the harder work it is doing to move the blood through the body due to narrowed arteries. Table 3-6a is the most often table used in Chapter 3 of the AMA Guides since coronary artery disease is a common condition we see in our cases.

COMMON MISTAKE: Many attorneys allege injury to the heart but fail to make sure that a treating physician, usually outside the workers’ compensation arena, or an evaluating physician orders a Doppler Study or cardiac ultrasound testing. This is a non-invasive ultrasound test that costs between $250.00 and $300.00 that can detect enlargement of the left ventricle and leaky heart valves. Equally lacking in the workers’ compensation arena are ultrasound studies of the carotid arteries that can detect narrowing of the main arteries to the brain. Leaky heart valves and narrowed carotid arteries place people at high risk of having a stroke, and these inexpensive tests can be life-saving and provide valuable information about potential WPI ratings.

The only difference between a Class 3 and Class 4 rating for CAD and each of the other cardiac conditions in Chapter 3 is that a Class 3 patient has a METS of > 5 but

The second most common cardiac condition we see in our cases involves arrhythmias which is on page 56 of the AMA Guides. In fact, this author successfully prosecuted a workers’ compensation case that involved a workers’ compensation defense attorney who had to retire due to severe atrial fibrillation that was aggravated by the stress of being a workers’ compensation defense attorney. An arrhythmia simply refers to a heartbeat that is generated at a site other than the sinus node. Some people who have an arrhythmia have no symptoms and experience no impairment. Others have syncope (fainting or loss of consciousness), weakness and fatigue, palpitations, dizziness, lightheadedness, chest heaviness, and shortness of breath, or any combination of the foregoing.

People who suffer from arrhythmias generally are at risk of having a stroke so many patients need to be on anticoagulant medication such as warfarin (Coumadin). Sometimes an electro-ablation of the area of the heart that is causing the arrhythmia is necessary to control or stop the arrhythmia. In other cases, a pace maker is installed and in rare cases a cardioverter-defibrillator is surgically implanted in the patient’s chest, for those who are at risk for sudden cardiac death. We see atrial fibrillation, sinus bradycardia (too slow heartrate), and ventricular tachycardia (too fast heartrate) in our cases.

CARDIOVASCULAR SYSTEM, SYSTEMIC AND PULMONARY ARTERIES—CHAPTER 4

AMA Guides Chapter 4 covers disorders of the systemic and pulmonary arteries. Of note to workers’ compensation cases is Table 4-2 on page 66, criteria for rating hypertension cases. Again, there are four classes of whole person impairments depending upon the severity of the hypertension and its effect on a person’s ADLs. Those classes have the same ranges within each class as do the cardiac tables in AMA Guides Chapter 3. Note there are three stages of hypertension listed in Table 4-1 on page 66 that are indexed to the severity of the disease in the WPI listings.

Notice in Table 4-1, page 66, Classification of Hypertension in Adults, a high systolic or a high diastolic blood pressure is sufficient for a diagnosis of hypertension; thus, you do not need both readings to be “high” in order to have the diagnosis. There has to be at least three separate “high” readings at different times in order to justify a diagnosis of hypertension. This criteria has changed in the years since the 5th Edition of the AMA Guides was published. Most physicians now believe that only two separate “high” readings at different times justifies a diagnosis of hypertension. For Stage 1 hypertension, a person only needs a systolic blood pressure reading of 140–159 or a diastolic blood pressure reading of 90–99.

The diagnostic criteria for hypertension listed on page 66 of the AMA Guides are outdated and obsolete. The three stages of hypertension listed in Table 4-1 are based on the Joint National Committee-6 (JNC-6). The JNC consists of medical experts in research and clinical practice who regularly meet and make recommendations to the medical community on issues involving cardiovascular medicine. The recommendations of the JNC have significant influence on the day to day practice of medicine and can be considered a national standard of care. On December 28, 2013, the JNC-8 arrived at a consensus-based revision of the diagnosis and recommended treatment of hypertension. Due to the very high population of people with hypertension the JNC-8 developed the Hypertension Management Algorithm that is a guide for physicians on how to treat hypertension. Current research shows that there is less than 50% medication adherence for patients who are diagnosed with hypertension and who are prescribed anti-hypertensive medications.

The current standard is to consider any person who is under 60 years of age to have hypertension if the blood pressure is greater than or equal to 150/90. If a person has blood pressure of greater than or equal to 160/100 then the person has what essentially is a “stage 3 hypertension” status using Table 4-1. There is no longer a stage 2 hypertension consideration. Any person who has blood pressure regularly between 140–149/80–89 have “prehypertension” which is not ratable for permanent impairment but is a warning sign. The standard medical treatment for hypertension today is for a physician to prescribe a diuretic such as hydrochlorothiazide (HCTZ) or an ACE inhibitor, or an Angiotensin Receptor Blocker (ARB) or a calcium channel blocker (CCB), or a combination of the foregoing. Counsel must be aware that these medications alone and in combination can have significant side effects which may cause ratable impairment.

COMMON MISTAKE: The American Heart Association has its own diagnostic criteria for cardiovascular hypertension which is more stringent than the JNC-8 criteria. A person is considered hypertensive if their systolic and diastolic numbers are 140/80 or higher. This is quite controversial since if this standard is widely adopted, the need for anti-hypertensive medication will sky-rocket across large age groups. Long term use of any medication has its own risks. In the context of the workers’ compensation system, counsel needs to ask physicians who diagnose cardiovascular hypertensive disease what diagnostic standard the physician is using as a basis for the diagnosis.

We use Tables 4-1 and 4-2 extensively in our cases, and you need to become very familiar with the rating methodology for hypertension. Undiagnosed, untreated or improperly treated hypertension can cause left ventricular hypertrophy (LVH) and ultimately heart failure (HF). Left ventricular hypertrophy is enlargement of the left lower chamber of the heart from which oxygen enriched blood flows from the heart to the body. LVH is a form of cardiomyopathy that is simply an “enlarged heart” in layman terms. A Class 3 and Class 4 hypertension WPI rating requires the existence of poorly controlled or long standing hypertension with severe consequences.

LVH takes from six months to two years to form because of non-diagnosed hypertension, poor hypertension control or a patient’s non-compliance with medication. In fact, up to 50% of hypertensive people in the United States do not comply with their hypertension medication regiment. The term “poor hypertension control” includes patients who are medication compliant but still show clinically significant hypertension despite multiple medications. This is called “malignant hypertension.” Heart failure means that the heart is not pumping blood hard enough to circulate blood properly in the body, causing fluid build-up in the legs (edema) and ultimately in the lungs and eventually leading to kidney failure. This is why a Class 3 WPI rating is between 30% WPI and 49% WPI and a Class 4 WPI rating is between 50% WPI and 100% WPI. These are very sick individuals who have serious hypertension and end organ disease as a result of it.

A recent case was quite vexing where the injured worker had normal blood pressure with four medications but still has a Class 4 impairment rating under Table 4-2. This was due to end organ damage including irreversible LVH and abnormal kidney function. Notice that Classes 1, 2, and 3 all have “and” and “or” separating some of the criteria, and a physician must provide an explanation of how and why an injured worker falls within one class or another and what WPI rating within a class applies with an explanation of why a specific WPI rating applies in the case.

COMMON MISTAKE: Many physicians do not discuss how and why a patient is placed within a class of impairment. For example, any Class 4 cardiovascular impairment is between 50% and 100% WPI. The AMA Guides do not provide any real guidelines as to where a physician should assign a given impairment rating within a class. When counsel deposes a physician, the doctor must describe how he or she arrived at a specific WPI rating—what was it based on?

For safety members (police, sheriff, and firefighters), pursuant to Labor Code § 3212 et. seq., there is the “heart trouble” presumption, among others. This means that any heart trouble is presumed to be work related. Labor Code § 4663(e) provides the anti-attribution of non-industrial factors to apportionment of permanent disability for certain specified safety members. This means you cannot apportion permanent disability to non-industrial factors and probably also means you cannot apply Benson v. Workers’ Comp. Appeals Board [(2009) 170 Cal. App. 4th 1535, 89 Cal. Rptr. 3d 166, 74 Cal. Comp. Cases 113] in these cases, at least according to some recent non-published WCAB panel decisions.

So what do you do with a safety member case where Labor Code §§ 3212 and 4663(e) apply and the injured worker has hypertension with LVH? Does the injured safety member get the heart trouble presumption? Since hypertension itself is not “heart trouble,” should the WPI rating for hypertension be subject to apportionment due to non-industrial factors such as a smoking history, diabetes, obesity, and family history? Both statements are correct, and a judge would have to parcel out impairment for the heart trouble that is not subject to apportionment under Benson or other applications of Labor Code § 4663, and the apportionment to other factors would apply to the impairment from the hypertension alone. How would this be accomplished? There is no case law on this subject yet but hypothetically, a physician could rate the heart trouble from the LVH using Table 3-9 on page 47, Cardiomyopathies, and the hypertension as a Class 1, 2, or 3 separately under Table 4-2. Then the physician applies principles of apportionment under Labor Code § 4663 to the hypertension portion of the WPI ratings only, leaving out the WPI rating for the LVH.

Other arguments may prevail, one by the defense whose argument is that the LVH is caused by the hypertension and, therefore, the whole thing should be subject to apportionment and the anti-attribution clause of Labor Code § 4663 does not apply at all to either the LVH or the hypertension. The applicant’s side would argue that the LVH and the hypertension that caused it are both so intertwined that you cannot parcel out apportionment between the LVH and the hypertension with reasonable medical probability. Case law will eventually have to resolve this issue along with precise medical analysis by a competent medical-legal evaluator.

Interestingly Table 4-4 on page 74 covers impairments of the upper extremity due to peripheral vascular disease. So does Table 16-17 on page 498 in Chapter 16, the Upper Extremities chapter. When you compare the two tables against each other, it is confusing which table is applicable in a given case. Notice that Raynaud’s phenomenon is covered in AMA Guides Chapter 4 and also in AMA Guides Chapter 16, Table 16-17 on upper extremities. If you have a case involving vascular insufficiency and possible amputation, then you want to refer to Table 4-4 and the explanation and examples. Remember, everything in the AMA Guides is indexed to how a disorder affects a person’s activities of daily living in Table 1-2 on page 4. Remember, too, that you have to multiply the upper extremity impairment times .6 to obtain the whole person impairment rating. So deep vein thrombosis for an upper extremity is rated in these tables in two different chapters. Counsel should make sure a physician reviews both tables to see which WPI rating is the most accurate and why.

Disorders and impairments of the lower extremities due to peripheral vascular disease are included in Table 4-5 on page 76 and in Table 17-38 on page 554 in Chapter 17, The Lower Extremities, and these two tables are identical. There can be a workers’ compensation case involving post-traumatic amputations or aggravation of diabetes resulting in loss of toes, feet, and legs that would be covered under this chapter. If the impairment is to a lower extremity due to peripheral vascular disease, regardless of which chapter you use to rate it, you have to multiply the lower extremity impairment rating by .4 to obtain the WPI rating. Table 4-7 on page 82 also has a helpful summary of systemic and pulmonary artery cardiovascular impairments. The medical term “claudication” means lameness (which can be neurogenic, discogenic, or vascular).

A person who has both a heart condition and vascular disease such as hypertension receives potentially two separate impairment ratings from the AMA Guides. For example, a patient who had a heart attack (myocardial infarction) due to coronary heart disease (CHD) or who develops an arrhythmia will receive an impairment rating from AMA Guides Chapter 3, Tables 3-6a and 3-6b, page 36, for the CHD or Table 3-11, page 56, for the arrhythmia, and a separate impairment from Chapter 4, Tables 4-1 and 4-2, page 66, for the hypertension. The impairment ratings from the two separate chapters (e.g., Chapter 3 for the CHD, and Chapter 4 for the hypertension) are combined using the Combined Values Chart. However, a patient who develops cardio-vascular hypertensive disease that results in left ventricular hypertrophy (LVH) would be rated under Chapter 4, with a Stage 3 or 4 hypertension rating only.

COMMON MISTAKE: Many panel QME physicians do not think they are “allowed” to assign separate ratings for CHD, arrhythmias, and hypertension in a severely disabled patient. That is not true, and this is why the Combined Values Chart is useful in cases like this. Some physicians think they can only rate the most severe condition and the rest overlap with the severe condition, which is not true.

Table 4-6 has WPI ratings for pulmonary hypertension, which is different than cardiovascular hypertensive disease. Pulmonary hypertension is a serious condition that affects the right ventricle of the heart and is diagnosed by chest x-ray and pulmonary artery pressure (PAP less than 40 mm Hg is normal). Pulmonary hypertension can be associated with chronic obstructive lung disease (COPD) from cigarette smoking and other lung diseases. In the context of work related injuries, a pulmonary embolism resulting from surgery that is from a work related injury can cause pulmonary hypertension. The examples in this section of the AMA Guides involve cases where the person has COPD or a pulmonary embolism.

The FEC adjustment for all heart related impairments in Chapter 3 of the AMA Guides is a [5], and the FEC adjustment for all of the Systemic and Pulmonary Arteries in AMA Guides Chapter 4 is also a [5], except for pulmonary circulation disease, which has an FEC adjustment of [7]. See page 2-2, of the 2005 PDRS. Remember, the adjustment factor for all parts of body for injuries occurring on or after 1/1/2013 is a multiplier of 1.4 or a 40% increase of each WPI rating.

It has become clear that use of AMA Guides Chapters 3 and 4 has resulted in higher permanent disability ratings overall compared with the 1997 Rating Schedule work restriction method of determining PD once everyone uses these AMA Guides chapters under the 2005 and 2013 PDRS. The AMA Guides do not describe rules governing apportionment or causation in any of the individual chapters involving conditions that result in permanent impairments. See the discussion of when a risk factor becomes causative in Chapter 8 of this guidebook. The two published appellate cases on apportionment, Escobedo and Gatten, involve orthopedic conditions (the knee and the lumbar spine, respectively) and there is no published appellate case that involves apportionment in a case that involves internal medical conditions such as heart disease or hypertension.

The physician (either the treating or evaluating) must justify where within a class a given case exists. Suppose an injured employee has back, heart, and diabetes impairments. The heart and diabetic conditions independently result in ratings within two separate classes or ranges of impairments in AMA Guides Chapters 3 and 10, respectively. The AME or PQME would have to determine where this case belongs within each class range (low, middle, or upper end). He or she could assign a mid-range WPI rating for the heart since the applicant had coronary by-pass surgery with moderate exertional residuals. The AME or PQME could also assign a WPI on the upper end of a rating range since the applicant had retinopathy and peripheral neuropathies from the diabetes.

© Copyright 2019 LexisNexis. All rights reserved. This article was excerpted from The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation, 2019 Edition, by Hon. Robert G. Rassp (LexisNexis).