4.3 Congestive Heart Failure
Estimates suggest that approximately 4.8 million individuals in the United States have congestive heart failure (CHF), with 400,000 new cases each year (National Institute of Health, 2000 based on National Health & Nutritional Examination Survey, 1988-1991). The prevalence of CHF increases with age. As can be seen in Figure 2, the prevalence of CHF is five times greater in individuals 70 years of age or older compared to those aged 40-59 (National Health & Nutritional Examination Survey, 1988-1991).
Figure 2 Prevalence of CHF by Age.
Source: National Health and Nutrition Examination Survey (1998-1991). National Center for Health Statistics.
Importantly, the prevalence of CHF is increasing. Data from the National Health & Nutritional Examination Surveys in 1976-80 and 1988-91 indicate that the prevalence rates increased for every age group (35 through 75) between the 1976-80 and 1988-1991 surveys.
In a recent study, Senni, Tribouilloy, Rodeheffer, et al.(1999) compared the incidence of CHF in Rochester, Minnesota in 1981 with that observed in 1991. Results of that investigation revealed no significant differences in the incidence, after adjustment for sex and age, and survival rates between the two cohorts. Thus, these data suggest that recent advances in the management of cardiovascular disease have done little to affect the incidence or survival of individuals with CHF between 1981 and 1991.
Common symptoms of CHF include shortness of breath, fatigue, and exercise intolerance. A decline in mental status is a common manifestation in CHF, an effect that may adversely affect driving performance. Recently, Cacciatore, Abete, Ferrara, et al. (1998) investigated the relationship between CHF and cognitive impairment in an older population. Results of that investigation revealed a prevalence of CHF in subjects with cognitive impairment (e.g., Mini Mental State Examination [MMSE] below 24) of 20 percent compared to a prevalence of 4.6 percent in individuals with CHF with a MMSE > 24. Zuccala, Cattel, Manes-Gravina, et al. (1997) also report a positive relationship between CHF and cognitive impairment. Results from that study revealed significant correlations between left ventricular ejection fractions and MMSE scores, with ejection fractions < 30 percent associated with lower MMSE scores. Acanfora, Trojano, Iannuzzi, et al. (1996) report the results of a multicenter study investigating cognitive impairment and CHF. Results from preliminary data from 183 individuals with a diagnosis of CHF revealed significant differences in cognitive functioning between patients with CHF compared to those without CHF. Significant impairments were noted on the MMSE, verbal fluency, immediate and delayed recall (Rey test), and attentional measures. Importantly, MMSE scores for individuals without CHF were, on average, 24 (± 5), suggesting that the level of impairment for those with CHF may be even more severe when compared to unimpaired healthy controls.
CHF and Driving Literature Review
The effects of CHF on driving performance are, unfortunately, largely unknown due to a paucity of research in the area. Fitness-to-drive guidelines for individuals with CHF have, however, been published by the Canadian Cardiovascular Society (CCS). The CCS fitness-to-drive guidelines for individuals with CHF are summarized below.
Recommendations from the CCS Consensus Conference (1996) for private drivers with CHF:
- No restrictions for private drivers that are Functional Class I-No functional limitations, (Able to achieve
5-7 METS [1 MET equivalent to resting oxygen consumption in the seated position and equivalent to 3.5 ml/kg/min])
Functional Class II-Mild functional limitations (Able to achieve 5-7 METS),
Functional Class III LV Class I-Ejection fraction 50 percent or more,
LV Class II-Ejection fraction 35 percent to 49 percent and Holter class II (No episodes of VT more than 3 beats in duration with an average cycle length 500 ms or less).