Approach to assessing fitness to drive in patients with cardiac and cognitive conditions

Post-MI (level III evidence).12

Private drivers (ie, those with noncommercial licences) who have suffered non–ST-segment elevation MIs with substantial left-ventricle damage can resume driving 1 month after the event, presuming there are no additional comorbidities that impose a longer waiting period. This recommendation is based on the rapidly decreasing risk of serious arrhythmias, myocardial rupture, and symptomatic heart failure after the first month, and allows a “stabilization” phase for new medical therapy. If patients have undergone coronary artery bypass grafting, they must wait 3 months before resuming driving.

Ischemic cardiomyopathy (level III evidence).12

In addition to having suffered a recent MI, the patient was also found to have substantial cardiomyopathy, with an EF of 28%. The moderate to severe mitral regurgitation indicates that some of the EF might be moving in a backward direction, and that the forward EF is likely less than 28%. While ischemic cardiomyopathy is a persistent condition, the risk posed in a driving context is that of cardiac arrhythmias and sudden death—acute intermittent conditions. Patients with severe cardiomyopathy who are private drivers face no restriction if they have NYHA class I (ie, no symptoms and no limitation in ordinary physical activity), class II (ie, mild symptoms [such as mild shortness of breath or angina] and slight limitation during ordinary activity), or class III (ie, marked limitation in activity due to symptoms, even during less-than-ordinary activity such as walking short distances) symptoms. In contrast, commercial drivers with an EF of less than 35% are no longer eligible for licensure, and commercial drivers with NYHA class III or IV (ie, severe limitations, with symptoms experienced even while at rest) symptoms are deemed ineligible to drive regardless of their EF.

Ventricular tachycardia and ICD implant (level III evidence).12

The patient suffered hemodynamically unstable VT and was implanted with an ICD for secondary prevention indications. The presence of VT makes the patient ineligible to drive for 6 months (during which time there must be no recurrences). The implantation of the ICD for secondary prevention also imposes a 6-month restriction.

The Canadian Cardiovascular Society guidelines state that when more than one disqualifying medical condition is present at the same time, the most restrictive recommendation is to be applied (level III consensus).12 Therefore, for this patient’s cardiac disease portfolio, a 6-month suspension from driving is recommended, during which time he must have no recurrence of his VT, must not have another MI, and must not deteriorate to NYHA class IV symptoms.

Delirium

In the period following discharge from hospital, residual delirium is a concern. Florid delirium is characterized by the following features: sudden onset and short duration; new-onset unpredictable hourly fluctuations in cognition; new-onset hallucinations; decreased attention or concentration; and changes in level of consciousness. When patients recover from such obvious deliriums in hospital, it can still take weeks to months for their mentation to return to normal. Many suffer from a slowly resolving subclinical delirium, which presents as slow mentation, decreased attention (ie, decreased focus), and altered scores on cognitive tests.

Those with an underlying dementia are more prone to developing delirium (ie, recurrent delirium or delirium precipitated by minor stresses are red flags suggesting underlying dementia). When such patients become delirious, the delirium often takes longer to resolve (weeks or months) and resolution might be incomplete, leaving them with permanent cognitive loss. The dementia is often “unmasked” by the delirium, leaving family members with the impression that the dementia began during hospitalization.

In Mr M.’s case the slow mentation suggests delirium, and the history of cognitive difficulties over the previous 6 months suggests an underlying dementia. It would be reasonable to tell the patient that he cannot drive for 6 months owing to his cardiac issues, during which time his noncardiac issues can be assessed and treated (Figure 1). During this recovery time, the physician can wean Mr M. off medications that might be contributing to the delirium (eg, benzodiazepines, narcotics), search for and treat reversible causes (eg, infection, postural hypotension [Box 1]), and decide if it is safe for Mr M. to continue living alone (eg, assess risks of malnutrition, medication errors, falls, fire, and inability to address emergencies). Should relocation to a supervised setting become necessary, the family can be directed to online resources (such as “Home to Retirement Home: A Guide for Caregivers of Persons with Dementia,” available from www.rgpeo.com/en/resources/RRR_Guide_Sept_09.pdf). As the delirium clears in a safe setting, the physician can assess the patient to determine if he has an underlying dementia.

Dementia

The assessment of fitness to drive in dementia is based on very limited evidence. Guidelines recommend employing the Mini-Mental State Examination,10 the clock-drawing test,14 and the Trail Making Test (parts A and B).15 In more advanced stages of dementia, performance on these cognitive tests might be so impaired that it will be clear that it would be unsafe for the patient to resume driving, and further testing is not required. Furthermore, driving is contraindicated in moderate to severe dementia, defined as a loss of the ability to perform 2 instrumental activities of daily living or 1 activity of daily living (grade B, level III evidence), owing to cognitive decline rather than physical disability.10,11 Activities of daily living and instrumental activities of daily living are reviewed in Figure 2.10,16

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Figure 2

Dementia and driving checklist for use by physicians and health care professionals*

ADL—activity of daily living, CMA—Canadian Medical Association, IADL—instrumental activity of daily living, MOT—Ministry of Transportation, OTC—over the counter.

*This figure is a shortened version of the 10-minute office-based dementia and driving checklist for use by physicians and health care professionals16; based on clinical opinion and experience, not evidence.

Adapted from Molnar et al16 with permission.

The true clinical challenge lies in the assessment of patients with mild dementia who require individualized assessment (grade B, level III evidence).11 In persons with mild dementia, the approach to assessment is relatively unstudied—a recent systematic review has demonstrated that no in-office cognitive tests have well-validated cutoff scores predicting fitness to drive in dementia (level I evidence).17 In recognition of this “evidence-based vacuum,” the Canadian Institutes of Health Research has funded a 5-year longitudinal prospective cohort study (www.candrive.ca) to derive and validate screening tests for fitness to drive that can be employed in front-line clinical settings. While we wait for the results of this research study, physicians can consider employing the experience-based approach to the assessment of fitness to drive in dementia depicted in Figure 2.10,16 This figure does not represent a scale with a scoring template, but rather a practical sequence of steps to follow to gather information, allowing physicians to best employ their clinical judgment regarding fitness to drive.

Box 1.

Common causes of postural hypotension: 3D-AID acronym.

Some patients’ fitness to drive might be too borderline to assess in a clinical setting; they will require on-road testing (grade B, level III evidence).11 When sending persons with dementia for on-road testing, it is important to let them know that if they pass they might need to repeat the on-road test every 6 to 12 months as the dementia progresses.18 Many patients will not pursue on-road testing when informed of this possibility. The cost of specialized comprehensive on-road tests varies from $50 to $800 (to be paid by the patient), depending on the province. The high costs in some provinces might discourage physicians from assessing fitness to drive, as it places physicians in the undesirable position of presenting patients with an ultimatum: pay for expensive on-road tests or stop driving. This type of interaction is destructive to physician-patient relationships and is unfair to patients of limited financial means. This barrier must be addressed at the provincial level by either improving funding to ministries of transportation so they can fund comprehensive on-road testing or involving organizations that would financially benefit from better funding of comprehensive on-road testing. When people are involved in car crashes, it is the ministries of health and the insurance industry that pay the extremely high immediate and long-term costs of care and disability. The health care system and the insurance industry could potentially save taxpayers and investors millions of dollars by funding comprehensive on-road tests. In order to improve access to well-funded on-road testing, medical organizations and patient advocacy groups need to push for such a shared-payer system.

Some patients with very mild or mild dementia might be determined to be safe to drive, albeit temporarily. In such cases the discussion of eventual driving cessation should be broached (grade B, level II evidence),11 and follow-up assessment of fitness to drive must be arranged approximately every 6 to 12 months (grade B, level III evidence).11,18 When assessment results indicate that patients are unsafe to drive, physicians must then engage in the often painful and emotionally charged process of disclosing findings. To view a step-by-step approach to disclosing to a patient that they are not fit to drive, we recommend The Driving and Dementia Toolkit, made jointly available by the Regional Geriatric Program of Eastern Ontario and the Champlain Dementia Network.19