Lecture 12: The Cardiovascular System and Biotechnologies Flashcards
What is CABG?
Coronary Artery Bypass Graph - a graph vessel from another area of the body is used to circumvent the occlusion and return blood flow. Requires open chest surgery.
What are indicators for the use of CABG?
- Disease of the LMCA
- Disease of all three coronary vessels (LAD, LCX, RCA)
- Diffuse disease not amenable to treatment with a PCI
Know the steps for the CABG procedure.
Anesthesia –> Incision –> Open rib cage –> Pericardium is incised –>
What technology is necessary for the CABG procedure?
Heart-Lung (Bypass) Machine
What is the effectiveness of CABG?
> 500,000 CABG/year
- 4-6 hour procedure
- 5-7 day hospital stay
- remain functioning for 10-15 y
- There are initial risk but most are minimal with the exception of post-pericardiotomy syndrome
Know the comparison for hospital stay and restenosis between PCTA, Stent, and CABG.
Hospital Stay: PCTA Stent> CABG
Know the comparison for costs and cos-effectiveness between PCTA, Stents, and CABG.
Cost:
CABG>PCTA>Stent, Drug-eluting stents ~CABG
What is “off-pump”?
When a section of the heart is stabilized, no need for cardio-pulmonary bypass
What is MICS CABG?
Minimally Invasive Cardiac Surgery - 3 small incisions with pump to reduce stress
What are the benefits for MICS CABG?
- No open sternum
- No heart-lung machine
- Reduces healing
- Reduced risk of infection
How is heart failure treated?
- Diet modification
- Moderate exercise
- Medication
- Heart Transplant
- Cardiac Assist Devices
- Artificial Heart
What is Stage A Heart Failure?
There is no diagnosis or symptoms of heart failure but the risk is high due to different risk factors.
What is Stage B Heart Failure?
Heart failure diagnosed by an EF < 40%, but no past or current symptoms.
What are the typical therapies for Stage A Heart Failure?
Stop smoking, start exercise, treat risk factors,.
What are the typical therapies for Stage B Heart Failure?
Stage A therapies + surgical consultation for coronary artery revascularization and valve repair or replacement.
What is Stage C Heart Failure?
Heart failure diagnosed with past or current symptoms, including shortness of breath, fatigue, and reduced exercise tolerance.
What are the typical therapies for Stage C Heart Failure?
Stage A therapies, ACE inhibitors + beta blocker + diuretic and digoxin.
Restrict salt intake, monitor weight and restrict fluid intake.
+ Spironolactone when symptoms remain severe
What is Stage D Heart Failure?
Advanced symptoms of heart failure after receiving optimal medical care
What are the typical therapies for Stage D Heart Failure?
Stage A-C therapies +
Evaluation for other treatments: heart transplant, ventricular assist device, other surgeries, continuous IV infusion of inotropic drugs, and research therapies.
What are the limitations of heart transplant?
Only about 2,500 donor hearts become available for transplantation each year
What are the two types of MHC molecules and where are they found?
Class I MHC: found on all nucleated cells
Class II MHC: found on APC
When is rejection highest?
Risk of rejection is highest right after surgery
What is induction therapy?
- Use of drugs to heavily suppress immune system right after transplant surgery.
- Patients keep taking some anti-rejection drugs for the rest of their life.
What is “immuno-compromised state”?
The recipient is susceptible to opportunistic viruses/diseases
What is “graft-versus-host disease”?
It is caused by T-cells within the donor tissue that can cause tissue damage in the recipient.
What is the state of cardiac assist devices today?
- Ventricular Assist Devices ( VADs)
- They can serve as a bridge (for more time to wait for decision/transplant)
- Or as a destination (permanent therapy)
What are the design requirements for artificial hearts?
- Provide correct flow
- Beat continuously
- Response to change in biological demand (variable output)
- Material
- Small
- Cannot heat beyond 41
- Needs power source
What is the state of the artificial heart today?
- AbioCor is used as a destination therapy, completely external
- SynCardia is used a bridge therapy
What is the state of the SynCardia heart?
- In clinical trials it has the highest bridge-to-transplant rate
- 70% of patients who receive artificial heart survive transplant
What is the state of the AbioCor heart?
- It was the first self-contained artificial health, but only fit large patients and laster for about 18 months
- The company has decided to change focus to VAD
What can be done about CAD in the developing world?
Preventative measures
How is CV health measured?
- Auscultation
- Blood Pressure
- Serum Cholesterol
What is auscultation and how is it used?
Listening to the sounds of the heart, such as for a “lub-dub”. Abnormalities can be found in children with congenital defects of adults with acquired health valve disease.
Limitation: In the developing world confirmation with a echocardiogram is difficult.
How is blood pressure measured and used?
BP is measured using a sphygmomanometer.
Normal blood pressure is <120/80 Hg for adults. A bit above this number is pre–hypertension, more above this number is hypertension.
Based on the results advice can be given to change diet or other risk factors.
What is LDL?
- Low-Density Lipoprotein Cholesterol - “bad” cholesterol
- Cholesterol builds up inside blood vessels.
What is HDL?
- High-Density Lipoprotein Cholesterol - “good” cholesterol
- Removes cholesterol from vessels to liver for excretion
How are serum lipid levels interpreted?
The optimal is LDL 60
What is the success of preventive measures?
- With a 10% drop in cholesterol levels, there is a decrease of 30% risk of heart attack.
- Large percent of pop do not have their levels controlled
- Limitation: Access to technology and money to pay for medications
How do we say if something should be adopted in the developing world?
GNI per capita x3 is acceptable
What are the challenges for Cardiothoracic surgery in the developing work?
- Availability, not many centers
- Number of surgeons decreasing
- Malpractice on rise
- Salary decreasing
- Too many patients
- Little access and funding
- Salaries are low
What are possible solutions for the challenges facing the developing world concerning cardiotoracic surgery?
- Stop poaching doctors
- Stop current approach (bringing few to US for treatment)
- Moved towards in-country strategies
