Introduction to Cardiovascular Disease and Hypertension

Measuring Cardiovascular Health (CVH)

To combat the prevalence of these diseases, the American Heart Association (AHA) developed strategic goals to improve Cardiovascular Health (CVH) across the population. In 2022, the AHA updated its assessment metrics from the "Life's Simple 7" to the Life’s Essential 8.

These eight metrics are used to score an individual's cardiovascular health on a scale of 0 to 100:

1. Healthy Blood Pressure
2. Healthy Blood Glucose
3. Healthy Weight
4. Physical Activity
5. Healthy Diet
6. Non-smoking
7. Healthy Lipid Profile
8. Sleep Habits

The total CVH score is calculated by summing the scores of these eight categories and dividing by eight: $\text{Total CVH Score} = \frac{\sum \text{Scores of 8 categories}}{8}$

A score of 80–100 indicates High CVH, 50–79 is Moderate, and 0–49 is Low.

Hypertension (HTN): The "Silent Killer"

Hypertension, or high blood pressure, is defined as having more than two consecutive readings that fall outside the normal range of 120/80 mmHg. It is a major risk factor for stroke, renal disease, and heart failure.

Blood Pressure Regulation and Classification

Blood pressure is determined by how much blood the heart pumps and how tight or relaxed the blood vessels are. The heart undergoes a repeating cycle of contraction (systole) and relaxation (diastole). Systolic pressure is the force exerted during contraction, while diastolic pressure is the force during relaxation.

The clinical classification for blood pressure is as follows:

• Normal: <120/80 mm Hg
• Elevated: 120–129 / <80 mm Hg
• Stage 1 Hypertension: 130–139 / 80–89 mm Hg
• Stage 2 Hypertension: $\ge$140 / $\ge$90 mm Hg

Primary vs. Secondary Hypertension

Clinicians distinguish between two main types of hypertension:

1. Primary (Essential) Hypertension: This accounts for about 90% of cases. The specific cause is unknown (idiopathic), but it is influenced by genetics, obesity, high sodium intake, low potassium intake, smoking, and stress. It is generally not reversible but can be managed.
2. Secondary Hypertension: This is caused by an identifiable medical condition, such as renal parenchymal disease, obstructive sleep apnea, or endocrine disorders like Cushing’s syndrome. Unlike primary hypertension, this type can often be reversed by treating the underlying cause.

Exam Tip: When assessing for secondary hypertension, look for specific triggers like drug/alcohol use, thyroid disease, or renal artery stenosis. In contrast, primary hypertension is often a lifestyle and genetic multifactorial issue.

Nutritional Management: The DASH Diet

One of the most effective dietary interventions for managing hypertension is the DASH diet (Dietary Approaches to Stop Hypertension). The DASH diet is designed to lower blood pressure and LDL cholesterol by emphasizing specific nutrients and food groups.

Nutrient Profile and Food Groups

The DASH diet focuses on high intakes of potassium ($K^+$), magnesium ($Mg^{2+}$), calcium ($Ca^{2+}$), fiber, and protein.

Sodium and Potassium Balance

Sodium reduction is a cornerstone of hypertension management. A single teaspoon of table salt contains approximately 2,300 mg of sodium. To stay within a 2-gram sodium diet, individual food items should ideally contain no more than 200 mg of sodium per serving.

Conversely, potassium intake has an inverse correlation with blood pressure; as potassium intake increases, blood pressure tends to decrease. However, clinicians must be cautious with patients on certain diuretics, as these can increase potassium loss.

Clinical Interventions

When lifestyle modifications like the DASH diet and increased physical activity are insufficient, healthcare providers may prescribe anti-hypertension (anti-HTN) drugs. These medications work through various mechanisms, such as altering blood volume, changing the force of heart contractions, or relaxing the blood vessels to reduce resistance.

Clinical Note: When evaluating a patient for hypertension, always ensure accurate measurement: the patient should be seated with back support, rested for 5–10 minutes, and the arm should be at heart level using an appropriately sized cuff.