High blood pressure(Hypertension)

Hypertension (HTN) or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. It is the opposite of hypo-tension.

Hypertension is classified as either 

1. Primary (essential) hypertension -
2. Secondary hypertension 

About 90–95% of cases are categorized as "primary hypertension," which means high blood pressure with no obvious medical cause. The remaining 5–10% of cases (Secondary hypertension) are caused by other conditions that affect the kidneys, arteries, heart or endocrine system.
    
   ^{Hypertension is one of the risk factor for}

• stroke,
• myocardial infarction, 
• heart failure and 
• arterial aneurysm,and 
• is a leading cause of chronic kidney failure

Prevalence of hypertension and cardiovascular risk 

 The association between elevated blood pressure and ischemic heart disease and cerebrovascular disease is well known. Each blood pressure increment of 20/10 mmHg doubles the risk of CAD(Coronary artery disease). Similarly, improving blood pressure dramatically reduces adverse health outcomes. In hypertensive patients, achieving a 12 mmHg reduction in systolic blood pressure (SBP) over 10 years will prevent 1 death for every 11 patients treated, making this one of the most powerful tools a physician has for preventing devastating illness and disability.A meta-analysis of clinical trials for various antihypertensive medications found that effective anti-hypertensive therapy reduces other CV outcomes as shown below.

Impact of effective anti-hypertensive therapy in reducing clinical outcomes.  

                Outcome                             Average percent reduction

                 Stroke                                             35-40%

                 Myocardial infarction                       20-25%

                 Heart failure                                     50% 

Classification of blood pressure: 
 The risk of cardiovascular complications associated with levels of blood pressure to introduce the following blood pressure classification system, used to set goals for hypertension control.

 “Prehypertension” is not a disease category, but a designation to identify patients at high risk of developing hypertension.


Once a patient has been identified as hypertensive, the clinician has four key objectives:

1. address potential lifestyle factors that may be elevating blood pressure, including diet, alcohol, and weight; 
2. identify other cardiovascular risk factors or concomitant disorders that will affect prognosis and guide treatment;
3. search for identifiable secondary causes of high blood pressure;
4. assess target organ damage.

Specific comorbidities are evaluated because they must also be treated, and because their presence may influence target blood pressure and therapeutic choices. These include:

• diabetes 
• renal insufficiency 
• hyperlipidemia 
• family history of heart disease 
• microalbuminuria 
• physical inactivity 
• obesity 
• tobacco use

Causes of secondary hypertension may indicate an alternative treatment strategy; they should be particularly sought in patients with an abdominal bruit, accelerated or resistant hypertension, recurrent flash pulmonary edema, renal failure, or onset of hypertension under age 30 without a family history. Potential causes of secondary hypertension include:

• sleep apnea
• drug-induced hypertension
• chronic kidney disease
• primary aldosteronism
• renovascular disease
• chronic steroid therapy or Cushing’s syndrome
• pheochromocytoma
• coarctation of the aorta
• thyroid or parathyroid disease.

Evidence of target organ damage is a key measure of the extent of disease. Examples include:

• Heart: left ventricular hypertrophy or CHF, as well as angina, MI, or a history of coronary revascularization
• Brain: stroke or transient ischemic attack
• Kidneys: renal insufficiency
• Arteries: peripheral arterial disease
• Eyes: retinopathy 

Treatment:  
The aim of treatment is to reduce B.P. to normal level and to reduce the risk of suffering a cardiovascular of cardiac accident to prevent as organ damage.

• ^{Patient with borderline hypertension diastolic 90 to 95 mm Hg require only no-drug therapy including weight reduction, decreased alcohol and Na+ intake relaxation therapy.}
• ^{Hypertension  patient should be stopped smoking since it is a potent risk factor for cardiovascular and cerebrovascular accidents. Again, smoking reduces the benefits of anti-hypertensive therapy if it is continued during treatment.}

^{Drug Treatment:}