Primary Risk Factor: Hypertension and Obesity
The primary risk factor for this patient's walking limitation is the combination of hypertension and obesity (BMI 31), which together drive left ventricular hypertrophy and create the pathophysiology underlying heart failure with preserved ejection fraction (HFpEF). 1
Why Hypertension and Obesity Are the Culprits
The patient's clinical presentation—exertional dyspnea with mild LVH and preserved ejection fraction in the setting of obesity and hypertension—is classic for HFpEF. 1 This is not a normal consequence of aging and represents pathology requiring intervention. 1
Synergistic Pathophysiology
Hypertension and obesity create a synergistic effect on cardiovascular risk that exceeds the sum of individual effects. 2 Among U.S. adults with hypertension, 49.5% are obese, demonstrating the clustering of these risk factors. 3
This combination directly drives left ventricular hypertrophy through pressure and volume overload. 4 Hypertension causes pressure overload through increased afterload and arterial stiffness, while obesity creates volume overload through a hyperdynamic state. 4
Obesity is present in >70% of adult HFpEF patients and independently increases symptom burden, exercise intolerance, and risk of LVOTO. 5 Patients who are obese have increased LV mass, are more symptomatic, and have reduced exercise capacity. 5
Hypertension treatment reduces heart failure risk by approximately 50%, demonstrating its causal role. 1 The relationship between stroke and blood pressure is "direct, continuous and apparently independent." 5
Why Other Options Are Incorrect
A) Smoking (Quit 15 Years Ago)
Former smoking contributes to atherosclerotic burden but is not the primary driver of current symptoms. 2 The patient quit 15 years ago, and while smoking cessation is critical for PAD progression, the immediate symptom burden relates to active hemodynamic factors. 2
Smoking is a well-documented modifiable risk factor for ischemic stroke and cardiovascular disease, but its impact diminishes significantly after cessation. 5
C) Normal for Age
Exercise intolerance requiring medical evaluation is never "normal for age" and represents pathology requiring intervention. 1 This dismissive approach delays appropriate diagnosis and treatment of HFpEF.
Age is a nonmodifiable risk factor, but the presence of symptoms with documented LVH indicates active disease processes that demand management. 5
D) Mild Left Ventricular Hypertrophy
LVH is not the primary risk factor—it is the consequence of the primary risk factors (hypertension and obesity). 6, 4 LVH represents target organ damage from these underlying conditions.
While LVH independently predicts cardiovascular morbidity and mortality, treating the root causes (hypertension and obesity) can lead to LVH regression. 5, 7
The heritability of LV mass falls between 0.3 and 0.7, but hypertension, obesity, and diabetes are the most important determinants of LVH. 6
Clinical Implications
The correct answer is B) hypertension and obesity because:
These factors are currently active and modifiable, unlike remote smoking history. 5, 1
They directly cause the pathophysiology (LVH and HFpEF) responsible for walking limitation. 1, 4
Treatment of these factors will improve outcomes, including symptom burden, exercise capacity, and cardiovascular events. 5, 1, 7
The combination creates multiplicative risk beyond individual effects, with 35.7% of obese individuals having hypertension. 2, 3
Management Priorities Based on Primary Risk Factors
Strict blood pressure control to target <140/90 mmHg using agents that promote LVH regression (beta-blockers or non-dihydropyridine calcium channel blockers preferred in this patient). 5, 1
Comprehensive lifestyle interventions for achieving and maintaining weight loss, which addresses multiple pathophysiological mechanisms and may lower risk of LVOTO, HF, and AF. 5, 1
SGLT2 inhibitors as first-line disease-modifying therapy for HFpEF, reducing heart failure hospitalizations and cardiovascular death. 1
Supervised walking program as cornerstone therapy, which increases pain-free and maximum walking distances despite initial discomfort. 1, 2