Advances in... Congestive Heart Failure Care Heart failure can currently be considered an epidemic. The article discusses some of the recent advances in outpatient management of congestive heart failure. Michael C.Y. Chan, MBBS, FRCPC, FACC; and Rosa Gutierrez, MN, NP Fact Box: Did you know? It is estimated 1.5% to 2% of the general population has congestive heart failure (CHF). Mortality due to CHF is around 50% five years after initial diagnosis. Cardiovascular disease, including CHF, is the number one cause of death in North America. CHF is one of the leading reasons for admission to hospital in Canada and the number one cause of hospitalization in people over 65. Recently, much effort has been put into research and development of evidence-based practice guidelines for congestive heart failure (CHF) diagnosis and treatment. 1 In the updated American College of Cardiology heart failure guidelines, 2 there is a new classification to emphasize early recognition and treatment of CHF. It is now appropriate to start pharmacotherapy and risk factor modification even before symptoms manifest or before detection of structural heart disease. How is CHF diagnosed? 1. Echocardiography CHF is mostly a clinical diagnosis and is relatively easy when the typical symptoms and signs are present. However, these symptoms and signs are not always present. Echocardiography should be obtained whenever CHF is suspected or even when it is confirmed. This test can often give clues to etiology, severity of structural heart disease and concomitant pathology. With most modern machines, the diastolic function and right and left heart filling pressures can often be estimated and may be a guide to treatment as well. 2. Diastolic CHF One-third to one-half of patients with CHF symptoms have preserved systolic function (ejection fraction [EF] > 45% to 50%) and no significant valve abnormalities on echocardiography. Diastolic CHF is one of the several terms proposed to define this condition. Although the overall prognosis of diastolic CHF is better than CHF with systolic dysfunction, the survival is less than that of the normal population. The most common etiologies are thought to be hypertension and coronary artery disease (CAD). Patients should be prescribed diuretics for symptom relief and the underlying conditions should be treated. 3. Diagnosing CAD CAD is the most common etiology of CHF; therefore, in all paients diagnosed with CHF, a careful history should be obtained for any history of angina-like symptoms and for any risk factors for CAD. If the history is suspicious, a cardiac perfusion imaging study, such as MIBI or thallium scan, should be obtained. If there is severe or unstable angina, or recently diagnosed myocardial infarction, consider going directly to coronary angiography. 26 Perspectives in Cardiology / February 2005
Table 1 CHF patients who should be admitted to hospital Severe decompensated CHF Severe symptomatic hypotension Poor perfusion states Shock Severe worsening creatinine Active ischemia Table 2 Measures to reduce frequency of readmission of CHF patients Correct etiologic and precipitating factors Start angiotensin-converting enzyme inhibitors and beta blockers before discharge Educate patient and family about medications, diet (limiting sodium intake), recognizing precipitating factors and suitable activity level Follow-up within 1-2 weeks Continue to monitor weight, electrolytes, renal function Ensure patient compliance with treatment Possible home nurse visit 4. BNP B-type natriuretic peptide (BNP) is released from the cardiac ventricles in response to increased wall tension. In the clinical setting, if unsure about the cause of dyspnea, the following ranges may be used to help with diagnosis: 1. BNP < 100 pg/ml: 0% to 2% probability of CHF; other etiologies have to be sought 2. BNP > 500 pg/ml: CHF very likely (95%); in most instances, need to admit to hospital for treatment 3. Grey zone, 100 pg/ml to 500 pg/ml: Need to workup; usually from RV strain Although there is strong evidence for the value of BNP in the evaluation of dyspnea of uncertain cause, further studies are needed before the widespread use of BNP is recommended. How is CHF treated? Certain patients suspected of having CHF should be admitted to hospital (Table 1). During hospitalization, specific measures should be taken to reduce the frequency of readmission (Table 2). The following is recommended for both inpatients and outpatients: 1. Diuretics Diuretics should only be used for congestive symptoms. Patients who do not have fluid overloaded may require only a small dose of diuretics or none at all. The patient s weight and jugular venous pulse are useful for assessing fluid status. The presence of ankle edema indicates fluid overload, but lack of edema does not rule it out. Patients whose diuretic dose is changed must have electrolytes and renal About the author... Dr. Chan is an associate clinical professor of medicine, University of Alberta, and the co-director, Heart Function Stabilization Program, Royal Alexandra Hospital, Edmonton, Alberta. About the author... Ms. Gutierrez is a cardiac nurse practitioner specializing in heart failure, and the co-ordinator, Heart Function Stabilization Program, Royal Alexandra Hospital, Edmonton, Alberta. Perspectives in Cardiology / February 2005 27
function checked within a few days to a week of the change. 2. ACE inhibitors and ARBs The recently published CHARM study is the only well-performed, randomized control trial for treatment of diastolic CHF. 3 In one arm of the study, patients with New York Heart Association functional class II-IV CHF and LVEF > 40% were randomized to the angiotensin receptor blocker (ARB), candesartan, 32 mg once daily, or placebo. After a median followup of 36.6 months, cardiovascular death did not differ between groups, but fewer patients in the candesartan group were admitted to hospital for CHF. Therefore, an ARB, in addition to diuretics, should be considered for treatment of diastolic CHF. Other arms of the CHARM study, as well as the VALIANT study, 4 did not show definite superiority of ARBs over angiotensin-converting enzyme (ACE) inhibitors; therefore, ACE inhibitors should still be first choice for HF treatment. In patients who are intolerant to ACE inhibitors, ARBs can be used. An ARB may also be used if the patient is already on a maximum dose of ACE inhibitor, but still symptomatic and/or relatively hypertensive. Note that ACE inhibitors and ARBs share some common adverse effects, such as hyperkalemia, rise in creatinine and hypotension. 3. Spironolactone The landmark RALES paper established the role of spironolactone, as a therapy that can lower mortality in classes III and IV CHF patients. One adverse effect of spironolactone is hyperkalemia; however, this effect can be avoided (Table 3). 5 4. Beta blockers Table 3 Avoiding hyperkalemia in CHF patients Start low-dose ACE inhibitor or ARB Do not exceed spironolactone, 25 mg QD Measure potassium and creatinine one week after starting or increasing ACE inhibitor/arb/ spironolactone; check potassium every month thereafter for 3 months If potassium > 5.5 mmol/l, stop ACE inhibitor/arb/sprironolactone If potassium is 5.0 to 5.5, lower doses of drugs (especially the spironolactone) Avoid spironolactone in patients with creatinine > 250 mmol/l (or GFR < 30mL/min), potassium > 5.5 mmol/l (irreversible) Use spironolactone only in systolic CHF (classes III, IV) Limit dietary intake of potassium (e.g., orange, tomato, melon, banana, certain herbs, etc.) Use loop diuretics concommitantly Consider using sodium bicarbonate, 650 mg tabs orally twice daily Avoid non-steroidal anti-inflammatories and COX-2 inhibitors Be cautious in older patients, women and those with diabetes ACE: Angiotensin-converting enzyme ARB: Angiotensin receptor blocker QD: Every day GFR: Glomerular filtration rate COX: Cyclooxygenase Beta blockers are indicated when EF < 45%, in addition to ACE inhibitors/arbs with diuretics, as needed to control symptoms. It is recommended to start beta blockers before discharge for patients admitted for decompensated CHF. The key is to make sure the patient has been adequately diuresed and is clinically stable, with electrolytes and creatinine in the acceptable range. In contrast to traditional teaching, beta blockers should be used in conditions such as diabetes, chronic obstructive pulmonary disease and peripheral vascular disease. Of course, great caution should be exercised in patients with recurrent hypoglycemia and asthma. Cont d on page 30 28 Perspectives in Cardiology / February 2005
Beta blockers should be started at a low dose with monitoring of blood pressure, electrolytes, renal function and any increase in dyspnea. In the office, the beta blocker should be up-titrated every two to four weeks, with monitoring of blood pressure, symptoms of lightheadedness, dyspnea, fluid overload and symptomatic bradycardia. ACE inhibitor and/or diuretic dosages may have to be adjusted to allow up-titration of the beta blocker. 1/3 to 1/2 of patients with CHF symptoms have preserved systolic function and no significant valve abnormalities on echocardiography. 5. Digoxin Digoxin should be considered for patients who have persistent symptoms of CHF despite therapy with diuretics, ACE inhibitors and a beta blocker, when the CHF is caused by systolic dysfunction. Digoxin should not be used for stabilization of patients with acutely decompensated CHF. The dosage of digoxin should be 0.125 mg daily in most patients, with lower doses being used in patients over 70, those with impaired renal function or those with a low lean body mass. Loading doses of digoxin are not necessary. The serum digoxin level should not be used to titrate up to a therapeutic level; rather, it should be used in patients suspected to have digoxin toxicity. In a post-hoc analysis of the DIG study, serum digoxin levels > 1.2 ng/ml were associated with increased mortality. It is now suggested digoxin may be more effective and safer in the range of 0.5 ng/ml to 0.8 ng/ml.
6. Nitrate/hydralazine A recent study showed a nitrate/hydralazine combination reduced mortality in patients with CHF. 6 Whether these results are applicable to the general population of patients with CHF is still under discussion. However, in patients who are intolerant to ACE inhibitors and ARBs, it is reasonable to use nitrate/hydralazine as vasodilators. What about device therapy? ICD Recent studies, including the SCD-Heft study, 7 have shown prophylactic implantation of implantable cardiovertor defibrillator (ICD) in ceratin CHF patients is beneficial in reducing mortality. The 2004 updated Canadian Cardiovascular Society guidelines now suggest considering ICD Take-home message In newly diagnosed CHF patients, start with a diuretic and an ACE inhibitor; an ARB can be used in patients intolerant to ACE inhibitors. Once a patient is stabilized, a beta blocker should be added early on; for sicker patients (class III-IV), add spironolactone, but beware of hyperkalemia. Nonpharmacologic treatments of CHF include reduction of sodium and fluid intake. Consider referral to a cardiologist for advanced therapies (e.g., angioplasty, CRT, implantable defibrillator). implantation in patients who are post ST-elevation myocardial infarct > 3 months and still have EF < 30%. 8 Patients who have a terminal illness with life expectancy < 12 months and those with refractory Cont d on page 32
class IV CHF not suitable for heart transplant should not receive ICD. CRT Cardiologists are increasingly implanting cardiac resynchronization (CRT) devices (biventricular pacemakers) in patients who have class III or IV CHF, are on optimal medications and have EF < 35%, QRS > 130 ms and sinus rhythm. These devices have been shown to improve exercise capacity, quality of life and may improve mortality as well. 9 Unfortunately, one-third of patients do not respond to CRT. There is ongoing research to identify patients with "dyssychrony," i.e. who will respond to CRT. What about nonpharmacologic management of CHF? Patients should understand the nature of the disease, etiology, treatmemt, medications, side-effects and most importantly, salt restriction and fluid limitation. One of the most frequent reasons for hospital admissions and emergency visits for CHF patients continues to be excessive intake of salt and fluid. Patients should be encouraged to cook without salt and to read labels when buying processed foods. It is also important to avoid salt substitutes that have potassium instead of sodium. Fluids should be limited to six to eight cups a day. Exercise in patients with CHF is safe and improves fitness and quality of life. Any patient with stable symptoms should be encouraged to walk daily or participate in low-intensity activities. PCard References 1. Demers C, Dorian P, Gianetti N, et al: The 2002/3 Canadian Cardiovascular Society consensus guideline update for the diagnosis and management of heart failure. Can J Cardiol 2003; 19(4):347-56. 2. Hunt SA, Baker DW, Chin MH, et al:acc/aha guidelines for the evaluation and management of chronic heart failure in the adult: Executive summary. Circulation 2001; 104(24):2996-3007. 3. Yusuf S, Pfeffer MA, Swedberg K, et al: Effects of candesartan in patients with chronic heart failure and preserved left-ventricular ejection fraction: The CHARM-Preserved Trial. Lancet 2003; 362(9386):777-81. 4. Pfeffer MA, McMurray JJ,Velazquez EJ, et al:valsartan, captopril, or both in myocardial infarction complicated by heart failure, left ventricular dysfunction, or both. N Engl J Med 2003; 349(20):1893-906. 5. Palmer BF: Managing hyperkalemia caused by inhibitors of the reninangiotensin-aldosterone system. N Engl J Med 2004; 351(6):585-92. 6. Taylor AL, Ziesche S,Yancy C, et al: Combination of isosorbide dinitrate and hydralazine in blacks with heart failure. N Engl J Med 2004; 351(20):2049-57. 7. Bardy GH, Lee KL, Mark DB, et al: Amiodarone or an implantable cardioverter defibrillator for congestive heart failure. N Engl J Med 2005; 352(3):225-37. 8. Armstrong PW, Bogaty P, Buller CE, et al:the 2004 ACC/AHA guidelines:a perspective and adaptation for Canada by the Canadian Cardiovascular Society Working Group. Can J Cardiol 2004; 20(11):1075-9. 9. Bristow MR, Saxon LA, Boehmer J, et al: Cardiac resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med 2004; 350(21):2140-50. 32 Perspectives in Cardiology / February 2005