ACSM - Pathophysiology/Risk Factors 5

What can aggressive control of modifiable risk factors do for the progression of CVD.

- may reverse, slow, or halt progression of atherosclerosis
- reduces ischemia, angina, recurrent CV events, revascularization

List common pharmacological therapies used to combat risk factors of CVD and give examples of each

1) Platelet inhibitors - aspirin, warfarin, clopidogrel
2) Anti-ischemic agents - ? adrenergic blockers, calcium channel antagonists
3) angiotensin-converting enzyme
4) aldosterone antagonists
5) digitalis
6) diuretics
7) lipid-lowering therapy

How do platelet inhibitors combat CVD?

- reduce CV events in ppl at high risk for CVD events
- follows revascularization procedures

How do ? adrenergic blockers combat CVD?

-reduce ischemia by lower myocardial O? demand for given workload
- lower BP and control ventricular arrhythmia
- 20 - 30% reduction in 1st year mortality rate in post-MI patients

How do calcium channel antagonists combat CVD?

-reduce ischemia at given workload by altering major determinants of myocardial O? supply and demand
- reduce resting and exercise HR and BP
- have not been shown to reduce post-MI mortality

How to nitrates combat CVD?

- reduce ischemia by reducing myocardial O? demand w/ small, accompanied increase in O? supply
- used to treat typical and variant angina
- have not been shown to reduce post-MI mortality

How do angiotensin-converting enzyme inhibitors combat CVD?

- reduces myocardial O? demand by reducing systemic vascular resistance, increasing exercise tolerance in those w/ left ventricular dysfunction
- causes vasodilation of systemic vasculature, reducing resting and exercise BP

How do aldosterone antagonists combat CVD?

- improves survival in patients w/ CHF
- blunts SA and AV node conduction, resulting in lower ventricular response in ppl w/ atrial fibrillation or tachycardia

How does digitalis combat CVD?

- enhances contractility of myocardium causing increased SV
- blunts SA and AV node conduction, resulting in lower ventricular response in ppl w/ atrial fibrillation or tachycardia
- used to treat ppl w/ CHF

How do diuretics combat CVD?

- reduces blood pressure by increasing renal excretion of Na+, K+ and other ions, resulting in loss of water as urine
- used when mild reduction of BP is needed
- slight effect on resting and exercise BP, but no effect on HR
- may increase exercise tolera

What is the goal of lipid-lowering therapy and how does this combat CVD?

- reduce availability of lipids to injured endothelium
- lowering LDL and TC is effective at decreasing progression and increasing regression of atherosclerosis

List the various classifications of lipid-lowering drugs and the mechanism by which they work.

1) Bile acid sequestrants - lower LDL, elevate TG
- bind bile acids and reduce recirculation thru liver
2) Niacin - lowers LDL, elevates HDL
- inhibits secretion of lipoproteins from liver
3) Statin drugs - lower LDL and TC
- newer statins are good at als

List 5 revascularization procedures

1) Percutaneous transluminal coronary angioplasty (PTCA)
2) PTCA w/ coronary artery stent
3) Atherectomy
4) Laser angioplasty
5) Coronary artery bypass graft surgery (CABGS)

What does PTCA involve? When is it used and what are the drawbacks?

- flattens plaque lining walls of artery, increasing artery diameter
- done on those w/ acute MI
- done on younger patients
- 30 - 50% chance of restenosis w/in 6 months

What does PTCA w/ coronary artery stent involve? When is it used and what are the drawbacks?

- PTCA and insertion of mesh tube that acts as scaffold to hold walls of artery open
- done on those w/ CAD or MI
- 10-15% chance of restenosis w/in 6 months

What does an atherectomy involve? When is it used and what are the drawbacks?

- similar to PTCA w/ various types
1) Rotational - uses high-speed rotational shaver to grind down plaque
2) Transluminal extraction - cuts and vacuums away plaque
- can be used w/ PTCA-stent
- similar drawbacks as PTCA

What does laser angioplasty involve? When is it used and what are the drawbacks?

- similar to PTCA, but catheter emits photons that vaporize plaque
- used when PTCA catheter can't be passed thru plaque buildup
- can be used w/ PTCA-stent
- similar drawbacks as PTCA

What does coronary artery bypass graft surgery involve? When is it used and what are the drawbacks?

- R or L mammary internal artery, saphenous vein, or other large vein is removed and attached at base of aorta and other points below coronary artery stenosis
- used for patients w/ extensive multivessel disease who don't respond to drugs, have failed PTC

What is risk stratification?

- placing individual in risk group based on set of known risk factors

What is the purpose of risk stratification?

1) provide guidance on need for med exam and exercise test before participating in exercise program
2) provide guidance for monitoring and supervision during exercise training
3) provide assistance in making recommendations for occupational, recreational

What is the goal of risk stratification?

1) Increase safety of exercise training
2) Increase efficacy of secondary prevention