CHF subspecialists outperform generalists
CHF subspecialists outperform generalists
Survey reveals important differences
The treatment regimen for CHF, when administered by a heart failure specialist, conforms more closely to guideline recommendations than care provided by a general cardiologist, according to a group of investigators studying the differences in CHF management practices between general cardiologists and cardiologists specializing in the treatment of CHF.1
The group sent a survey examining diagnostic and treatment practices to 750 cardiologists and 118 CHF specialists. The specialists chosen for the study were members of the Society of Transplant Cardiologists or principal investigators in CHF trials. The self-reports showed that both groups follow published guidelines, but there were important differences between the practice patterns of general cardiologists and CHF specialists:
- Initial evaluation. In patients being evaluated for the first time, cardiologists use a chest X-ray more than subspecialists (47% vs. 12%), whereas specialists are more likely to use an echocardiogram (73% vs. 48%). The large majority of both groups measure left ventricular function as part of the evaluation. They also report the use of other testing procedures for patients who show CHF symptoms but do not have angina. Specialists reported using several tests more frequently than other cardiologists — nuclear medicine quantification of ejection fraction, right heart catheterization, measurements of exercise capacity, cardiac catheterization and angiography, and endomyocardial biopsy. It is uncertain whether this pattern reflects a higher proportion of patients being evaluated for cardiac transplantation and whether such diagnostic measures mean better patient care.
- Angiography vs. stress testing. Both groups are likely to evaluate their patients for ischemia and the need for possible revascularization, even in patients not having angina. However, CHF specialists tend to use coronary angiography as the initial diagnostic test, whereas general cardiologists are more likely to use stress testing. A majority of both specialists and general cardiologists indicated they believe revascularization in selected patients could improve symptoms and prognosis. A substantial proportion of the patients with clinical coronary disease managed by both groups undergo revascularization, but the percent was lower among those treated by specialists. Coronary bypass surgery was reported to be the procedure in the majority of cases by both groups, but the percentage undergoing angioplasty was higher in patients managed by general cardiologists (37% vs. 21%).
- Monitoring stable patients. Both physician groups reported that their usual approach to monitoring stable patients is clinical assessment by history and physical examination. General cardiologists are more likely to use repeat chest X-rays (12% vs. 4%) or echocardiograms (30% vs. 22%), whereas specialists are more likely to use serial measurements of exercise capacity (3% vs. 18%).
- ACE inhibitor use. Specialists more often use angiotensin-converting enzyme (ACE) inhibitors as part of their initial therapy in patients with mild to moderate CHF and during maintenance therapy. In both mild to moderate and severe CHF, the specialists are more likely to initiate a three-drug regimen consisting of a diuretic, an ACE inhibitor, and digoxin. During maintenance therapy, most patients are given combination therapy. In patients with mild to moderate CHF, specialists indicated that they use ACE inhibitors more often than general cardiologists (91% vs 80%). However, among patients with severe disease, both groups of physicians reported using ACE inhibitors in a similar proportion of patients. Specialists are more likely to use digoxin, hydralazine, and beta-blockers regardless of the severity of symptoms.
Specialists are more likely than cardiologists to titrate ACE inhibitors to higher doses, even in the presence of renal dysfunction. The usual approach reported by 75% of specialists but only 35% of cardiologists is to titrate to high doses (defined as >75 mg/day of captopril, 15 mg/day of enalapril, or equivalent doses of other agents) if tolerated.
General cardiologists are more likely to titrate to symptomatic responses or to a lower dose (65% vs. 25%). This results in half of the patients of specialists being maintained with these high doses compared with less than a third of cardiologists’ patients. Reported ACE inhibitor use in patients with asymptomatic left ventricular dysfunction is also higher among CHF specialists (88% vs. 75%).
One apparent reason for the greater use of ACE inhibitors by specialists is their greater willingness to institute and continue these drugs in patients with renal dysfunction, either pre-existing or arising during ACE inhibitor therapy. Thus 87% of specialists but only 52% of general cardiologists reported that they would initiate an ACE inhibitor in a patient with a serum creatinine >3.0 mg/dL. Similarly, 64% of specialists but only 45% of general cardiologists indicated that they would continue ACE inhibitor therapy if it were associated with a rise in serum creatinine >1.0 mg/dL.
The practices reported by the CHF specialists conform more closely with the major recommendations of published guidelines than those of general cardiologists, according to the investigators.
"The literature shows that CHF clinics get better results," says Randall Williams, MD, a CHF cardiologist at a specialized program at Evanston (IL) Hospital. The investigators note that because CHF specialists use ACE inhibitors more aggressively, that practice may, in part, explain the success of the CHF clinic model. This also raises the possibility that some portion of the CHF population may be more optimally managed by cardiologists with a special interest in and additional training or experience with this condition.
The seven-page, 32-question, self-administered survey contained questions keyed to the major points of the Agency for Health Care Policy and Research guidelines2 and dealt with the evaluation, diagnosis, and treatment of CHF patients. Questions dealing with medical therapy were focused on patients with disease caused by left ventricular systolic dysfunction (ejection fraction <40%). Separate questions dealt with patients considered to have mild to moderate and severe CHF.
Williams says, "Data are consistent that if a physician is focused on one particular disease, day in and day out, he’s likely to be more effective and likely to abide by the accepted standards and guidelines." He explains that CHF cardiologists are more comfortable with, and more likely to use, beta-blocker therapy as well as other treatment modalities that go beyond ACE inhibitor use, which have been shown to increase patient function and survivability. "CHF cardiologists also are more aggressive in identifying reversible causes of the disease and in addressing ischemia or arrhythmia issues."
References
1. Bello D, Shah NB, Edep ME, et al. Self-reported differences between cardiologists and heart failure specialists in the management of chronic heart failure. Am Heart J 1999; 138(1):100-107.
2. Konstam MA, Dracup K, Baker DW, et al. Heart failure: Evaluation and Care of Patients with Left Ventricular Systolic Dysfunction. Publication no. 94-0612. Rockville (MD): Agency for Health Care Policy and Research; 1994.
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