Hypertension and Acute Stroke

J Nugroho

Departement of cardiology and vascular, Dr Soetomo Hospital

Faculty of medicine , Airlangga University

Stroke is a rapid clinical syndrom occured when the flow of oxygen-rich blood to a

portion of the brain is blocked and become one of the leading causes of death in the world. It also

become one of the main causes of physical or mental disability in the productive age and the

elderly , and can cause death within a short time. It spell out why stroke has a particularly strong

impact. In Indonesia based Riset kesehatan dasar (Riskesdas) ,there is an increasement on stroke

prevalance from 8,7 per 1000 (Riskesdas 2007) to 12,1 per 1000 (Riskesdas 2013) . DI

Yogjakarta is the second highest prevalance of stroke after Sulawesi Selatan with 10,3%.

Stroke has 2 broad catagories, hemorrhagic and ischemic. Ischemic stroke is caused by

restricted or interrupted blood and therefore oxygen supply to an area of the brain while

haemorrhagic stroke is caused by bleeding into an area of the brain, due to rupture of a blood

vessel or abnormal vascular structure in the brain. Ischemic stroke is classified into Transient

Ischemic Attack (TIA), Cerebral trombosis, and Cerebral Emboly while hemorhagic stroke

classified into intracerebral and subarachnoid hemorhagic stroke. Morbidity based on

pathophysiology of stroke obtained 66 % is caused by embolism stroke infarction ,24%

intracerebral hemorrhage stroke , and 4 % subarachnoid hemorrhage stroke

T he burden of stroke is likely to increase substantially in the future because of the aging

population. Apart from implementing effective stroke prevention programs, identification of

factors associated with more severe stroke may help to ease the burden of this coming epidemic

Risk Factor of stroke is divided into modifiable and unmodifiable. Modifiable risk factor are

smoking, hypertension, blood glucose. and un modifiable risk factor are age , gender,and genetic.

Blood preassure is believed to be main risk factor for hemorrhagic and ischemic stroke.

The damage that high blood preassure causes happens over time and is often only diagnosed

when considerable damage has already happened to the body’s blood vessels. If you have

hypertension you are unlikely to have any obvious symptoms for a long time. This study will

worked on obsevation of which type of stroke mostly caused by hypertension.

DEFINITION AND CLASSIFICATION OF STROKE

Stroke is a functional disorder of the focal brain more than 24 hours (unless there is a

surgical intervention or death), derived from the brain blood flow disorders. Included such as

subarachnoid hemorrhage, intracerebral hemorrhage and ischemia or cerebral infarction.

Circulatory disorders of the brain, brain tumors, stroke secondary to trauma is not included

(WHO MONICA, 1986;Hackeet al., 2003).Most widely accepted definition of stroke is a

syndrome characterized by symptoms or clinical signs which are growing quickly in the form of

functional focal brain impairment and globally that lasted more than 24 hours (unless there is a

surgical intervention or bring death), which is not caused by reasons other than vascular causes.

This definition includes a stroke due to cerebral infarction (ischemic stroke), non-traumatic

intracerebral hemorrhage , intraventricular hemorrhage and several cases of subarachnoid

hemorrhage (Warlow et al, 2007).Stroke can be divided into two main categories, haemorrhagic

stroke and ischemic stroke. In the hemorrhagic stroke, covered craniumwill contains too much

blood, whereas in ischemic stroke, there is disruption of blood availability in the brain area

results lack of oxygen and nutritional needs.Each category of stroke also can be divided into

several subtypes, which have different coping strategies

INFARCT STROKE

Infarct stroke is caused by lack of blood flow to the brain, approximately 85% of all

strokes are caused by ischemic stroke or infarction. Normally, the blood flow to the brain is 58

ml / 100 g of brain tissue per minute. If it was down to 18 ml / 100 g of brain tissue per minute

then the electrical activity of neurons stalled but still in good cell structure, so that the clinical

symptoms are still reversible. If Decreasing blood flow to the brain gets worser, it can cause

brain tissue died, which is often referred as infrak. Thus, ischemic brain infarction arises because

of a long and severe brain changes in brain structure and function that is irreversible.

Ischemic stroke can occur in the form of a thrombotic stroke (large and small blood vessels);

embolic stroke (with or without cardiac factors and / or arterial known); systemic hypoperfusion

(Watershed or stroke in the Border zone area); or venous thrombosis. A thrombus can stem from

several different causes, which can alter susceptibility to thrombolytic drugs. The primary cause

of thrombus formation in ischemic stroke is atherosclerosis (in-situ thrombus or

thromboembolism) or establishment in the heart (cardioembolic). Regardless of the cause,

decreased vascular supply to the brain is an important event in the majority (85-90%) of acute

stroke.

The clinical course of patients with stroke infrak would correspond to a decreasing blood

flow in brain tissue, as described above. The clinical course of cerebral ischemia will be able to

classify into

Transient ischemic attack (TIA)

A TIA is caused by a brief pause in blood flow to part of the brain — the result of a

temporary or partial blockage. The symptoms of a TIA resemble those of a stroke but they do not

last as long. Most symptoms disappear within an hour, although some may persist for up to 24

hours. Usually, no permanent brain damage occurs as a result of a TIA. According to the

National Stroke Association, approximately 5 million Americans have experienced at least one

TIA.

TIA Symptoms

Patients suffering a TIA may describe a “veil” or “window shade” partly covering the

vision of one eye that clears up spontaneously after several minutes. This represents the

temporary blockage (occlusion) of the retinal artery to the eye. There may also be dizziness,

imbalance, loss of coordination, confusion, difficulty speaking or understanding, and generalized

weakness.

There is no way to differentiate the temporary symptoms of a TIA from those of an acute stroke.

All patients need medical evaluation urgently. About one-third of those who have a TIA

eventually will have an acute stroke. Many strokes can be prevented by heeding TIA warning

signs and treating underlying risk factors.

Thrombotic Ischemic Stroke

Thrombotic stroke is caused by a thrombus (blood clot) that develops in an artery

supplying blood to the brain — usually because of a repeated buildup of fatty deposits, calcium

and clotting factors, such as fibrinogen and cholesterol, carried in the blood. The body perceives

the buildup as an injury to the vessel wall and responds the way it would to a small wound — it

forms blood clots. The blood clots get caught on the plaque on the vessel walls, eventually

stopping blood flow.

There are two types of thrombotic stroke:

Large vessel thrombosis, the most common form of thrombotic stroke, occurs in the

brain’s larger arteries. The impact and damage tends to be magnified because all the

smaller vessels that the artery feeds are deprived of blood. In most cases, large vessel

thrombosis is caused by a combination of long-term plaque buildup (atherosclerosis)

followed by rapid blood clot formation. High cholesterol is a common risk factor for this

type of stroke.

Small vessel disease (lacunar infarction) occurs when blood flow is blocked to a very

small arterial vessel. It has been linked to high blood pressure (hypertension) and is an

indicator of atherosclerotic disease.

Thrombotic disease accounts for about 60 percent of acute ischemic strokes. Of those,

approximately 70 percent are large vessel thrombosis.

Embolic Ischemic Stroke

A blood clot that forms in one area of the body and travels through the bloodstream to

another where it may lodge is called an embolus. In the case of embolic stroke, the clot forms

outside of the brain – usually in the heart or large arteries of the upper chest and neck – and is

transported through the bloodstream to the brain. There it eventually reaches a blood vessel small

enough to block its passage.

Emboli can be fat globules, air bubbles or, most commonly, bits and pieces of atherosclerotic

plaque, such as lipid debris, that have detached from an artery wall. Many emboli are caused by a

cardiac condition called atrial fibrillation—an abnormal, rapid heartbeat in which the two small

upper chambers of the heart (called the atria) quiver instead of beating. Quivers cause the blood

to pool, forming clots that can travel to the brain and cause a stroke. Cardiac sources of

embolism account for 80 percent of embolic ischemic strokes.

Ischemic Stroke Symptoms

The signs of ischemic stroke are similar to those of a TIA, except the damage can be

permanent. The most common indicator is sudden weakness of the face, arm or leg, most often

on one side of the body. Other warning signs may include:

sudden numbness of the face, arm, or leg, especially on one side of the body;

sudden confusion, trouble speaking or understanding speech;

sudden trouble seeing in one or both eyes;

sudden trouble walking, dizziness, loss of balance or coordination; and/or

sudden severe headache with no known cause (most common with hemorrhagic stroke).

The symptoms depend on the side of the brain that's affected, the part of the brain, and how

severely the brain is injured. Stroke may be associated with a headache, or may be completely

painless. Therefore, each person may have different warning signs

HEMORRHAGIC STROKE

Hemorrhagic stroke occurs when a vessel in the brain suddenly ruptures and blood begins

to leak directly into brain tissue and/or into the clear cerebrospinal fluid that surrounds the brain

and fills its central cavities (ventricles). The rupture can be caused by the force of high blood

pressure. It can also originate from a weak spot in a blood vessel wall (a cerebral aneurysm) or

other blood vessel malformation in or around the brain.

Damage can be caused in two ways. As in the case of ischemic stroke, oxygen- and nutrient-rich

blood is prevented from reaching the brain cells beyond the point of rupture. In addition, leaked

blood can irritate and harm the brain cells in the areas where it accumulates.

It is the location of the hemorrhage, rather than the amount of bleeding, that tends to be

the bigger factor in influencing the severity of the stroke. For example, bleeds in the brainstem,

though relatively tiny, can be quite lethal, whereas the same-sized bleed in the frontal lobe may

not even be noticeable.There are two types of hemorrhagic strokes. They are differentiated by

where the ruptured artery is located and where the resulting blood leakage occurs.

Intracerebral Hemorrhage (ICH)

This type of stroke is caused by the sudden rupture of an artery or blood vessel within the

brain. The blood that leaks into the brain results in a sudden increase in pressure that can damage

the surrounding brain cells. If the amount of blood increases rapidly, the sudden and extreme

buildup in pressure can lead to unconsciousness or death. Approximately 10 percent of all

strokes are intracerebral hemorrhages. They occur most commonly in the basal ganglia where the

vessels can be particularly delicate. High blood pressure (hypertension) is the most common

cause of this type of stroke. Less common causes include trauma, infections, tumors, blood

clotting deficiencies, and abnormalities in cerebral blood vessels.

Blood vessel abnormalities in the brain include arteriovenous malformations (AVMs) and

arteriovenous fistulas (AVFs). AVMs and AVFs, also called lesions, are abnormal connections

between cerebral arteries (which carry blood to the brain) and veins (which take blood away

from the brain). AVMs appear to be acquired prior to birth (congenital) and tend to form near the

back of the brain. Although AVFs can be congenital, more often they are caused by a trauma that

damages an artery and a vein which are side by side in the brain. These blood vessel

abnormalities can cause a host of problems, but the two most common are pressure against the

adjacent parts of the brain, causing neurological problems (such as seizures, paralysis or loss of

speech), and bleeding (hemorrhage) into surrounding tissues. Hemorrhage from cerebral

arteriovenous abnormalities represents from 2 percent to 4 percent of all strokes.

Subarachnoid Hemorrhage (SAH)

Subarachnoid hemorrhage occurs when bleeding from a damaged vessel causes blood to

accumulate between the brain and the skull, in the subarachnoid space, and press on the surface

of the brain instead of dispersing into the tissue. The leaked blood can irritate, damage or destroy

surrounding brain cells. When blood enters the subarachnoid space, it mixes with the

cerebrospinal fluid (CSF) that cushions the brain and spinal cord. This can block CSF

circulation, which leads to fluid buildup and increased pressure on the brain. The open spaces in

the brain (ventricles) may enlarge, resulting in a condition called hydrocephalus. This can make a

patient lethargic, confused or incontinent. The large accumulation of blood increases the pressure

surrounding the brain, interfering with brain function.

The leaked blood also can produce a condition called vasospasm in which the vessels

narrow, impeding the flow of blood to the brain. This can result in an ischemic stroke. The

condition typically develops five to eight days after the initial hemorrhage. Most often, a

subarachnoid hemorrhage occurs because a cerebral aneurysm, an abnormal bulging outward in

the wall of an artery, ruptures. SAH also can occur because blood leaks from abnormal blood

vessel connections (AVMs and AVFs) near the surface of the brain.

Cerebral Aneurysm

A brain aneurysm is a weak bulging spot on the wall of a brain artery very much like a

thin balloon or weak spot on an inner tube. Aneurysms form from wear and tear on the arteries,

and sometimes from injury, infection or an inherited tendency.

There are two types of aneurysm:

Saccular – This is the most common type. It has a neck and stem and is also known as a

“berry” aneurysm because of its shape.

Fusiform – This is a less common type of aneurysm. It is an outpouching of the wall on both

sides of the artery and does not have a stem.

Aneurysms that cause subarachnoid hemorrhage are usually located at the base of the brain in the

Circle of Willis. This is an area in which a lot of blood pressure changes occur and where a lot of

vessels branch off, which can expose them to weakness.

Although it is not possible to predict whether an aneurysm will rupture, an aneurysm is more

likely to do so when it has a diameter of 7 millimeters or more. Unruptured brain aneurysms can

be medically treated to prevent a possible rupture.

Sudden & Severe Symptoms

Symptoms of a hemorrhagic stroke appear without warning. The sudden increase in

blood volume within the rigid skull (cranium) creates intense intracranial pressure that cannot be

released. This, in turn, may trigger a severe (“thunderclap”) headache, neck pain, double vision,

nausea or vomiting, loss of consciousness or even death.

About 17 percent of strokes are hemorrhagic. The average age at which people suffer

hemorrhagic stroke tends to be lower than for ischemic stroke. This is because many of the risk

factors are related to unhealthy behaviors, such as smoking or drug use, rather than the effects on

the body of aging. The fatality rate for hemorrhagic strokes is higher than for ischemic strokes

and overall prognosis is poorer.

HYPERTENSION

Hypertension is a public health problem and a term used to describe HBP. It is a

condition that occurs as a result of repeatedly elevated blood pressure exceeding 140 over 90

mmHg whereby a systolic pressure above 140 with a diastolic pressure above 90. However,

normal blood pressure is below 120/80; readings between 120/80 and 139/89 is called pre-

hypertension. Systolic blood pressure is the pressure in the arteries as the heart contracts and

pumps blood forward into the arteries whereas diastolic represents pressure as a result to relation

of the arteries after contraction. (Zareian 2004; Cunha 2011.)

It has been called a silent killer as it is usually without symptoms. Hypertension takes a long time

before diagnosed thereby causing major health problems as stroke and other cardiovascular

diseases. Damage to organs as the brain, heart, kidneys and eye and so on are the long term

effect of high blood pressure disease. (Cunha 2011.)

Diagnosis of high blood pressure is usually measured with a device called sphygmomanometer.

This consist of an inflatable rubber cuff, an air pump and a column of mercury or a digital

readout reflecting pressure in an air column as well as electronic blood pressure machines. The

readings are widely expressed in millimeters of mercury or mmHg.

Diagnosis of high blood pressure is not based on a single reading except when it is extremely

high (above 170-180/105-110).

CLASSIFICATION OF HYPERTENSION

Category SBP MMHg DBP MMHg

Normal <120 <80

Prehypertension 120-139 80-89

Hypertension, Stage 1 140-159 90-99

Hypertension, Stage 2 >= 160 >=100

HBP and ischemic stroke

About 87% of strokes are ischemic strokes. Again, they are caused by narrowed or

clogged blood vessels in the brain that cut off the blood flow to brain cells.

Because HBP damages arteries throughout the body, it is critical to keep your blood pressure

within acceptable ranges to protect your brain from this often disabling.

HBP and hemorrhagic stroke

About 13% of strokes are hemorrhagic strokes, which occur when a blood vessel ruptures

in or near the brain. When a blood vessel ruptures, it can bleed into the deep tissue in the brain or

in the space between the brain and the skull.

High blood pressure damages the arteries and can create weak places that rupture easily or thin

spots that fill up with blood and balloon out from the artery wall (called an aneurysm). Chronic

HBP or aging blood vessels are the main causes of this type of stroke. Acute stroke BP

management during the acute phase of stroke is a matter of continuing concern.

Hypertension Management in CVA

The results of a small trial called Controlling Hypertension and Hypertension

Immediately Post-Stroke (CHHIPS) suggested a beneficial impact in administering lisinopril or

atenolol in patients with acute stroke and a SBP >160mmHg The same was the case for the

Acute Candesartan Cilexetil Therapy in Stroke Survival (ACCESS) study which suggested

benefits of candesartan given for 7 days after acute stroke. This latterhypothesis was properly

tested in the Angiotensin-Receptor Blocker Candesartan for Treatment of Acute Stroke

(SCAST) trial involving more than 2000 acute stroke patients. SCAST was neutral for functional

outcomes and CV endpoints, including recurrent stroke, and could not identify any subgroup

with significant benefit. A recent review gives a useful update of this difficult area.

Previous stroke or transient ischaemic attack

Data from three major placebo-controlled RCTs of antihypertensive treatment in patients

with a recent (but not acute) stroke or TIA which provide somewhat conflicting evidence. No

evidence is yet available that recurrent stroke is prevented by initiating therapy when BP is in the

high normal range, nor is there evidence for reducing SBP to <130mmHg. As prevention of

stroke is the most consistent benefit of antihypertensive therapy and has been observed in almost

all large RCTs using different drug regimens, all regimens are acceptable for stroke prevention

provided that BP is effectively reduced . Meta-analyses and metaregression analyses suggest that

calcium antagonists may have a slightly greater effectiveness on stroke prevention ], but the two

successful trials in secondary stroke prevention used a diuretic or a diuretic in combination with

an ACE inhibitor . Greater cerebrovascular protective effects have also been reported for ARBs

vs. a variety of other drugs in single trials and meta-analyses.

A 2014 review of blood pressure management during acute stroke, concluded that more

research is needed to identify which patients are likely to benefit from lowering blood pressure,

when the treatment should be given, and what types of stroke are likely to respond favorably.

The review, published in Cochrane Database of Systematic Reviews, included 26 trials involving

more than 17,000 patients

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