3. HF, Transplantation, LVADs

Question 3: In adult persons living with HF, a LVAD, or heart transplant who are considering driving, what is the risk of death or SCI (including SCD) within 1 year, stratified according to sex, age, and LVEF? In this section, the most frequent marker for SCI is sudden death, and available data allow us to stratify patients on the basis of functional class and EF.

Heart failure

HF, a clinical syndrome with signs and symptoms secondary to structural/functional cardiac abnormalities, pulmonary, and systemic congestion,^[46],[47] can affect the ability to drive safely (Table 3). Classification of HF is on the basis of LVEF, and categories include HF with reduced EF (HFrEF; LVEF ≤ 40%), HF with mildly reduced EF (LVEF 41%-49%), HF with preserved EF (HFpEF; LVEF ≥ 50%), and HF with improved EF (EF > 10% increase from a reduced LVEF of ≤ 40%).^[46],[47] Approximately half of all patients with HF have HFpEF.

Mortality associated with HF is attributed to SCI, progressive pump dysfunction, and death from noncardiac causes, the last of which becomes progressively more common as LVEF increases.^[48],[49] The overall 1-year mortality after diagnosis is between 25% and 40%. The median survival for HF patients is currently 1.7 years for men and 3.2 years for women^[48] with an age-adjusted mortality overall of nearly 6% at 1 year and 45% at 5 years.^[50] Mortality risk in any given patient is influenced by many factors including treatment of the underlying cause, use of guideline-directed medical therapy, and use of device therapy, including implantable defibrillators for primary and secondary prevention with and without resynchronization.^[51] Recent VAs that have occurred in patients with HF affect the fitness to drive risk assessment in the months after the arrhythmic event. Risk of death estimated from randomized clinical trials might not reflect risk in everyday clinical settings because of the stringent eligibility criteria of trials.

HF remains among the most common causes for hospital admission in older adults, with readmission rates of 27% and 36% within 30 and 90 days, respectively,^[52] and mortality risk of 15% at 90 days after discharge.^[53],[54] An important consideration when assessing risk, however, is that SCD in the setting of HF is almost invariably arrhythmic and might be the result of either ischemia-induced or scar-related malignant ventricular arrythmias.^[55] In addition, the rates of SCI in patients with HF varies across the EF spectrum,^[56] such that similar SCI rates are observed in patients with HF with mildly reduced EF (LVEF ≤ 49%; 28%) and HFrEF (LVEF ≤ 40%; 34%) but SCI rates are substantially lower in patients with HFpEF (LVEF 50%-59%; 20%).^[56] Severity of symptom burden on the basis of NYHA functional class can also be used to estimate risk. For example, patients who are NYHA class IV with HFrEF and being treated with infusions of inotropes (either intermittent outpatient or home inotropes) have at least a 0.5%-2% mortality per week and are therefore medically unfit to drive.^[57]–[59] Patients who have NYHA class IV symptoms and HFrEF but not treated with inotropes have a mortality of 35% at 3 months^[60] and a risk of SCD of 50%. Fitness to drive becomes less clear in the patient with NYHA class IV symptoms who improves to NYHA class III. One-year mortality in patients with HFrEF and NYHA class III symptoms is estimated at 12%-27%, with 30%-50% of these related to sudden deaths^[60]; this poses an acceptable risk for private driving (acceptable SCI annual risk in private drivers is 22%), but not for commercial driving (acceptable SCI annual risk of 1%).

Patients with NYHA class II symptoms are at lower risk overall but still have a proportionally higher risk of SCD and less risk of progressive HF. On the basis of the accumulated evidence from Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION),^[61] Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT),^[62] and Guiding Evidence-Based Therapy Using Biomarker Intensified Treatment in Heart Failure (GUIDE-IT),^[63] the annual risk of mortality in the treatment groups was 7%-15%.^[64] These risks are within the acceptable limit of annual SCI of 22% and as such patients who are NYHA class II are fit for driving a private motor vehicle, but again this risk would be too high to allow commercial driving.

Patients with NYHA class I symptoms are at the lowest risk for an incapacitating cardiac event and are therefore acceptable for private driving. For those patients with an LVEF < 30% there is a 10% annual risk of death and a 5% annual risk of SCD. Commercial driving therefore is not recommended for patients with an LVEF < 30%, even if they are asymptomatic, because the acceptable SCI annual risk for commercial drivers has been set at 1%.

Guidance for patients with HF and ICDs is provided in the Rhythm and Devices: CIEDs, Bradyarrhythmias, and Tachyarrhythmias section.

Cardiac transplantation

Although there is concern regarding transplant rejection in heart transplant recipients, particularly early in the post-transplant period, this decreases with time from transplantation. Of greater concern is the risk of SCD, which is associated with 10% of all post-transplant deaths and is thought to be a result of cardiac allograft vasculopathy.^[65],[66] Little is known about the time course between the development of cardiac allograft vasculopathy and SCD.

Practical issues such as sternal healing must also be considered. Therefore, transplant patients should not drive privately until at 6 weeks post transplant. This should be evaluated on an individual basis, however, because many patients might remain deconditioned at the 6-week mark post-transplant and might still be unfit to drive.

Commercial driving risk assessment should be determined on the basis of cardiac function and functional class. Patients who are beyond 6 months from the time of their transplant, receiving stable immunotherapy, with a LVEF 50% and NYHA classification of I are acceptable for commercial driving. For patients more than 5 years after transplantation, there is an increasing risk of underlying cardiac graft vasculopathy and most transplant centres perform surveillance annually with annual exercise testing, pharmacologic stress imaging for ischemia, or coronary angiography. These patients continue to be within acceptable risk for commercial driving if there is no evidence of active ischemia, with a LVEF 50% and NYHA classification of I.

When the risk of early complications and primary graft dysfunction has passed, heart transplantation offers a median survival of > 10 years, often with preservation of quality of life. As noted, the risk of progressive cardiac graft vasculopathy increases after 5 years, and remains the leading cause of eventual graft dysfunction and recurrent HF. As such, the guidelines for driving and travel for HF patients with NYHA classification of III or greater symptom burden could be applicable to patients developing late graft dysfunction.

LVADs

In 2012, the CCS published a focused position statement on fitness to drive for those with LVADs^[5] on the basis of emerging evidence of sufficiently low SCI rates and an increasing proportion of patients receiving LVADs for destination therapy. An increasing number of patients are undergoing implantation with LVADs for the treatment of advanced HF to improve their functional capacity and quality of life. In fact, 80% of patients are classified as NYHA class I or II at 6 months after implantation.^[67]–[70] In addition, improvement in device technology and the use of LVAD support for destination therapy results in the potential for longer duration of LVAD support, including some now with > 10 years of device therapy.

In 2 studies in which patients with LVADs were surveyed, most patients believed that their self-perceived safety of driving was adequate.^[71],[72] However, a small percentage of patients (16%) experience minor device alarms (battery or suction alarms) while driving. In 1 study of 94 patients, 1 patient experienced a syncopal event.^[72] In addition, 16% of LVAD patients indicated that the LVAD moderately/severely affected their concentration whereas 28% indicated that their ability to drive was moderately/severely affected.^[72] These data suggest that driving might be reasonably safe for stable patients, although more evidence is required to make definitive recommendations. Patients with an LVAD have the potential to experience VAs (ventricular tachycardia [VT] or ventricular fibrillation [VF]) and therefore will typically also have an implantable cardioverter defibrillator. However, because of the nature of LVAD support, they are at much lower risk for syncope or even sudden death.

The recent Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) registry (2012-2018) of > 16,000 patients who underwent continuous flow LVAD support documented 1-, 3-, and 5-year mortality rates were 18%, 39%, and 58%, respectively.^[73] Adverse events in those with continuous flow LVADs included stroke, gastrointestinal bleeding, device malfunction, and infection. Most of these events are highly unlikely to result in sudden incapacitation. Cardiac and device failure are generally slow and progressive, and death in most patients with LVADs is not sudden in nature. Device failures are almost exclusively related to the external portion of the drive line that do not result in sudden failure of the LVAD. Even abrupt loss of power to the pump does not result in SCI, but rather HF, unless the aortic valve has been oversewn. These data include the first 2 months postimplantation when patients should be excluded from driving, so the risk would be even lower for those beyond the 2-month mark. On the basis of these data, at most between 0.35 and 1.5 events that might result in sudden incapacitation could occur per patient-year.

Thus, patients with LVADs would appear, even in worst-case scenario calculations, to have a < 22% annual risk of SCI, making them eligible for private driving. However, they still have a rate of SCI that is > 1%, which falls short of the standard required for commercial driving. We recommend that patients who are stable with LVAD support (NYHA class I-II), discharged from hospital, and are at least 2 months postimplantation be allowed to drive a private motor vehicle.

Fitness to drive recommendations for patients with LVAD support and cardiac transplant are provided in Table 3.