UBP 4.4 (Short Form): Obstetrics – Ischemic Cardiomyopathy

Question 1

What would you like to know about this patient?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 1

There are several things I would like to know, including:

1. the obstetric plan, as this may affect my initial workup and anesthetic plan;
2. a more detailed history concerning her ischemic cardiomyopathy, which I would obtain by reviewing the patient’s chart, interviewing her, and calling her cardiologist to determine the location of the cardiac damage, which coronary vessels are compromised, whether there is additional myocardium at risk, any past and current symptomatology, and any procedural or pharmacological interventions that have occurred;
3. how concerned I should be about potentially difficult airway management (given this patient’s height and weight, the physiological changes of pregnancy, and her high blood pressure suggesting possible preeclampsia), which I would determine by examining her airway and identifying any anesthetic history of difficult airway management;
4. the condition of the baby, as this may affect the urgency of the preoperative workup and any obstetric intervention;
5. whether her elevated blood pressures were due to preeclampsia and, if so, whether there were any associated complications, such as coagulopathy, renal insufficiency, or cerebral edema;
6. her history of tobacco use and any associated pulmonary disease; and
7. her blood sugar level along with the severity, stability, current therapy, and any end-organ effects resulting from diabetes.

Question 2

What will you consider while performing your physical exam?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 2

1. First, I would carefully examine the patient’s airway, since this patient’s obesity, pregnancy, and potentially edematous airway (pregnancy and possible preeclampsia) all increase the risk of difficult airway management.
2. Second, considering her ischemic cardiomyopathy, I would perform a careful cardiovascular and pulmonary examination to assess her heart rate, rhythm, and signs of congestive heart failure such as jugular venous distension, pulmonary edema, hepatomegaly, and peripheral edema.
3. Third, with her smoking history, I would obtain a history, auscultate her lungs, order a chest x-ray, and consider pulmonary function testing to determine the nature and severity of any pulmonary disease.
4. Fourth, since this patient is diabetic, potentially preeclamptic, and may have congestive heart failure, I would carefully evaluate her volume status (urine output, capillary refill, skin turgor, etc.).
5. Fifth, given the patient’s elevated pressures and the possibility that she is preeclamptic, I would examine her for signs of coagulopathy such as bleeding at the intravenous insertion sites, bleeding of the gums, and/or excessive bruising.
6. Finally, if not already available I would order appropriate lab work such as urinary protein, H/H, blood sugar, electrolytes, platelets, and possibly cardiac enzymes.

Question 3

What do you make of these ECG findings?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 3

Both the Q-waves and the left axis deviation suggest a prior myocardial infarct;

the fact that the Q-waves are noted in leads II and III suggests that it was an inferior infarct.

Therefore, I would consider focusing subsequent monitoring on this area of the heart, where additional myocardium may remain at risk.

However, I would keep in mind that the ECG of a normal healthy pregnant patient may exhibit abnormalities like left axis deviation, ST-segment depression, and a Q-wave in lead III.

Question 4

What would you do to optimize this patient’s cardiac condition?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 4

Given the complicated nature of optimizing this potentially pre-eclamptic patient with a history of recent myocardial infarction and cardiomyopathy, I would develop a plan in close consultation with her cardiologist.

One of my goals would be to ensure adequate intravascular volume to prevent significant hypotension with the initiation of regional anesthesia, while at the same time, avoiding fluid overload in this patient with a cardiomyopathy and, possibly, pre-eclampsia-induced increases in capillary permeability.

Depending on the patient’s left ventricular function, I would also give consideration to afterload reduction and/or the administration of inotropes.

Moreover, I would ensure the continuation of any current B-blocker therapy (it is a Class I recommendation to continue B-blocker therapy in patients undergoing noncardiac surgery who are currently taking beta-blockers for treatment of indicated conditions).

Question 5

You note that she is not currently taking a B-blocker.

Considering her cardiovascular risk factors, would you initiate B-blocker therapy now?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 5

Recognizing that the routine administration of high-dose B-blockers without titration to patients not currently taking B-blockers who are undergoing noncardiac surgery is NO longer recommended,

I would only initiate B-blockade in consultation with her cardiologist (therapy may be indicated in this case due to her unstable cardiac condition).

While the preoperative initiation of B-blocker therapy in the absence of titration may reduce cardiovascular morbidity and mortality, it also leads to an increased incidence of hypotension, bradycardia, and stroke, along with an increase in overall mortality.

Clinical Notes:

• The initiation of carefully titrated B-blocker therapy at least 7 days prior to surgery should occur based on the following:
  
  • Beta-blockers should be continued in patients undergoing surgery who are currently taking beta-blockers for treatment of indicated conditions (Class I).
  • Beta-blockers titrated to heart rate and blood pressure are probably beneficial for patients undergoing vascular surgery OR intermediate-risk surgery who have coronary artery disease or cardiac ischemia identified during preoperative assessment OR more than 1 clinical risk factor for CAD identified during preoperative assessment (Class IIa).
  • In patients undergoing intermediate-risk OR vascular surgery with a single clinical risk factor identified during preoperative assessment (other than CAD), the usefulness of beta-blockers is uncertain (Class IIb).
  • In patients undergoing vascular surgery who are not currently taking beta-blockers and have no clinical risk factors, the usefulness of beta-blockers is uncertain (Class IIb).
  • In patients undergoing noncardiac surgery who are not currently taking beta-blockers, routine administration of high-dose, untitrated perioperative beta-blockers is NOT recommended (Class III).
  • Perioperative withdrawal of beta-blockers should be avoided unless absolutely necessary (Class I).
  • In general, beta-blockers should be started well in advance of a planned procedure (at least 7 days) and carefully titrated perioperatively to achieve adequate heart rate control (heart rate of 60-80 beats/minute)

• Active Cardiac Conditions (According to the ACC/AHA Guidelines):
  
  • Unstable coronary syndromes
    
    • Unstable or severe angina
    • Recent MI (>7 days but = 1 month)
  • Decompensated heart failure
    
    • Functional Class IV heart failure
    • Worsening or new onset heart failure
  • Significant arrhythmias
    
    • High-grade AV block
    • Mobitz II AV block
    • Third degree AV block
    • Symptomatic ventricular arrhythmias
    • SVT with uncontrolled ventricular rate (>100 beats/min at rest)
    • Symptomatic bradycardia
    • Newly recognized VT
  • Severe valvular disease
    
    • Severe or symptomatic aortic stenosis
    • Symptomatic mitral stenosis
      
      • Progressive dyspnea on exertion
      • Exertional presyncope
      • Heart failure

• Clinical Risk Factors (According to the ACC/AHA Guidelines):
  
  • History of compensated or prior heart failure
  • History of cerebrovascular disease (CVA)
  • Diabetes mellitus
  • Renal insufficiency

• Recommendations (Classification of Recommendations)
  
  • Class I: Benefit >>> Risk
  • Class 2a: Benefit >> Risk
  • Class 2b: Benefit >/= Risk
  • Class 3: Risk >/= Benefit

Question 6

What are the ACC/AHA recommendations for perioperative beta-blockers?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 6

According to the ACC/AHA recommendations in 2007, beta blockers should be continued in patients already receiving beta-blockers to treat angina, symptomatic arrhythmias, HTN, or other cardiovascular conditions;

they should be started in patients undergoing vascular surgery who have demonstrated risk for myocardial ischemia by preoperative testing.

Likewise, B-blockers are recommended for patients undergoing intermediate risk or vascular surgery in whom preoperative assessment identifies CAD or high cardiac risk, as defined by – history of ischemic heart disease, compensated or prior heart failure, cerebrovascular disease, diabetes, or chronic renal insufficiency.

However, perioperative beta-blocker use is uncertain in:

1. patients undergoing either intermediate-risk or vascular procedures with a single risk factor in the absence of coronary artery disease, or in
2. patients undergoing vascular surgery with no clinical risk factors.

Moreover, in situations where B-blockers are indicated prior to surgery, they should be titrated to heart rate and blood pressure over at least 7 days prior to surgery.

The initiation of B-blocker therapy in the absence of titration may reduce cardiovascular morbidity and mortality, but there is evidence that it may also lead to an increased incidence of hypotension, bradycardia, and stroke, along with an increase in overall mortality.

Question 7

Would you order a CXR or an Echocardiogram?

(A 44-year-old, G3P2 female at 38 weeks gestation, with a history of severe preeclampsia during her first pregnancy, presents to the obstetric floor with ruptured membranes. She is a 5’3”, 265 lb., insulin dependent diabetic who smokes 1.5 packs of cigarettes per day. Her obstetrician tells you she has ischemic cardiomyopathy and experienced a heart attack a little less than a month ago. Vital signs: HR = 98, BP = 156/93 mmHg, Hgb 11.4 mg/dl. ECG: NSR, Q waves in leads II, and III, and left axis deviation.)

Answer 7

If not already available, and if the patient exhibited signs of unstable coronary syndrome or uncompensated congestive heart failure, I would order a CXR and an echocardiogram to more accurately assess the patient’s cardiac condition.

More specifically, a CXR would detect the presence of cardiomegaly and/or pulmonary congestions,

while an echocardiogram would detect regional wall motion abnormalities and provide a derived left ventricular ejection fraction.