Cardiovascular procedures like cardiac echocardiography and extracorporeal circulation are used to diagnose and treat heart conditions. Cardiac echocardiography uses ultrasound to create detailed images of the heart, allowing observation of heart tissue, valves, blood flow, and other metrics. Extracorporeal circulation involves circulating blood outside the body during open-heart surgery using a heart-lung machine. Thrombolytic drugs like tPA are also used to dissolve dangerous blood clots and restore blood flow in emergencies like strokes and heart attacks.
2. Overview of the Cardiovascular
System:
This system is powered by the heart, which pumps
blood, oxygenated by the lungs, throughout the
body to distribute oxygen. The blood also collects
waste products from the cells, like carbon dioxide.
Problems with the heart or blood vessels can
result in permanent damage to the body or death
due to lack of oxygen, so it is extremely important
that ailments are recognized and appropriate
actions taken. Following this slide are examples of
a few procedures done to keep the cardiovascular
system up and running.
3. Cardiac Echocardiography:
taking a sonogram of the heart
Often referred to as a cardiac ECHO, this procedure should
not be confused with electrocardiography. An ECHO uses
ultrasound techniques, using sound waves to create a highly
detailed picture of a moving heart.
Many observations can be made using an echocardiogram,
especially using the latest systems which use 3D imaging in
real-time.
4. How echocardiograms are performed:
Transthoracic echocardiogram: An
echocardiography transducer (probe which
picks up echoes of sound waves, then
converts them into moving images) is placed
on the patient’s thorax, noninvasively
producing images through the chest wall. The
standard way, very fast and accurate,
pictured right.
Transesophageal echocardiogram: The probe is passed through the patient’s
esophagus; used when a transthoracic procedure does not produce a clear
enough picture. Rarely used.
Stress echocardiogram: Images are first taken at rest, then compared to images
produced when a patient is exercising in order to assess the heart during
physical activity.
5. What echocardiography can tell us:
Accurate observations and evaluations of the following can
be made using echocardiography:
health of cardiac tissue and valves
congenital heart disease
the velocity of blood
ischemia
leaks and regurgitation in the heart
cardiac output
the size and shape of the heart
atrial fibrillation
heart murmurs
pericarditis
endocarditis
6. Extracorporeal circulation:
circulation of blood outside the body
During cardiopulmonary
bypass, or open-heart
surgery, gravity drains blood
from the superior and inferior
vena cavae into a heart-lung
machine’s reservoir. This
blood is then pumped
through a membrane
oxygenator, which
oxygenates the blood. Finally,
the blood is pumped back
into the body via the aorta.
Sensors regulate blood
temperatures, oxygen
saturation, blood gases, pH,
and pressure.
7. How the heart-lung machine attaches to
the cardiovascular system:
Rigid cannulas are inserted into the vena cavae and aorta.
8. Although most patients recover successfully,
there are complications associated with
extracorporeal circulation:
arrhythmias
Atrial, caval, or aortic tears/bleeding
injury/obstruction due to malpositioning of
cannulas
air embolization
ischemia
epicardial vessel damage
unstable angina
9. Thrombolytic therapy:
the use of drugs to dissolve blood clots
Tissue plasminogen activator (tPA) is the most
commonly used drug to break up blood clots and
restore blood flow. It is an enzyme that catalyzes the
conversion of plasminogen into plasmin (an enzyme
which breaks down blood clots).
Other drugs can also be used,
such as streptokinase and
lanoteplase.
10. When are thrombolytics are used?
When clotting in the body is obstructing
blood flow and causing problems.
Ischemic strokes are caused by clots in
the brain and if there is no bleeding,
thrombolytics can quickly dissolve these
clots. Best results occur within three
hours of the first stroke symptoms.
Heart attacks occur when a clot is
blocking the arteries to the heart and
some of the cardiac tissue dies.
Thrombolytics can restart perfusion and
prevent cardiac damage, but will only be
used if there is no bleeding within the
body or high blood pressure.
11. Complications of thrombolytic
therapy:
Although there are not many
complications, hemorraging and internal
bleeding is the most common risk and,
in some cases, can be life-threatening.
In about 25% of patients, minor bleeding
from the gums can occur.
In about 1% of patients, bleeding of the
brain can occur.
