CV HTN Flashcards
What fraction of time is spent in diastole?
2/3
What fraction of time is spent in systole?
1/3
What is the major determinant of SBP?
CO
What largely determines DBP?
Total peripheral resistance (TPR)
Define CO
Fxn of SV, HR, & venous capacitance
Define PCT (What is it responsible for?)
- Major site for NaCl & NaHCO3 reabsorption
- Responsible for 60-70% of total reabsorption of Na
What permits rapid reabsorption of CO2?
Conversion of HCO3 to CO2 via carbonic acid
What is the most common loop diuretic?
Furosemide (Lasix)
- Others: Bumetanide, Torsemide
What are the most common thiazides?
- Chlorthalidone
- Hydrocholorothiazide (HCTZ)
What are the most common potassium sparing?
- Amiloride
- Triamterene
What is the most common aldosterone antagonist?
Spironolactone
What does diuresis result in?
Decreased plasma & SV
Diuretics MOA
Blocks reabsorption of Na & Cl
- H2O follows due to the osmotic pressure within the nephron created by the ions
Define TAL (What is it responsible for?)
- Pumps Na, K, & Cl out of lumen into kidney
- Major site of Ca & Mg reabsorption
- Responsible for 20-30% of Na reabsorption
Loop diuretics MOA
- Blocks Na+K+Cl- symporter at TAL
* More potent diuresis, smaller decrease in PVR, & less vasodilation
Loop diuretics: Efficacy
- Diuresis exceeds BP lowering
- Preferred in HF or severe edema
- Less likely to cause hyperglycemia, hyperlipidemia
What are some characteristics of Furosemide?
- Short duration of action
- Poor anti-hypertensive
- Use in pts w/ kidney disease or fluid retention
What is Torsemide?
Effective BP med at low dosage
What 2 meds are used in tx of hypercalcemia?
- Furosemide
- Torsemide
Describe the DCT (What is it responsible for?_
- Pumps Na & Cl out of lumen via Na/Cl carrier (NCC)
- Target of thiazide diuretics
- Responsible for 5-8% Na reabsorption
- Ca also reabsorbed via PTH
Thiazide diuretics MOA
- Blocks reabsorption of Na & Cl in DCT, H2O follows
- Initial diuresis - decreased plasma & SV
- Provides chronic anti-hypertensive action via decrease in PVR & SM relaxation
What does ADH do?
Facilitates H2O reabsorption from collecting tubule by activation of V2 receptors
What do V2 receptors do?
Stimulate adenyl cyclase via Gs
What does increased cAMP cause?
Insertion of additional aquaporin (AQP2) channels into mem
What is the action of ADH & desmopressin?
Reduce urine volume & increase [ ]
What are ADH & desmopressin useful for?
Pituitary diabetes insipidus
- But they are of no value in the nephrogenic form of diabetes insipidus
What can cause significant H2O retention & dangerous hyponatremia?
Tumors producing peptides
What syndrome can be tx w/ demeclocycline & conivaptan?
Syndrome of inappropriate ADH secretion (SIADH)
What is the goal of HTN tx?
Reduce morbidity & mortality from CV events
What is the equation for BP?
BP = CO x TPR
What is the fxn of angiotensin blockers?
Reduce PVR & blood volume
What is the fxn of sympatholytic agents?
- Reduce PVR by inhibiting cardiac fxn –> increased venous pooling
- Reduces SV
What do CCBs do?
Inhibit Ca influx –> coronary & peripheral vasodilation
What is the fxn of diuretics?
Deplete the body of Na & reduce blood volume
What is the fxn of aldosterone antagonists?
Inhibits aldosterone –> inhibits Na/H2O retention & vasoconstriction
What is the fxn of direct vasodilators?
Relaxes SM –> Reduced pressure –> dilated resistance vessels & increased capacitance
What are some examples of drug families that can be used together?
- Diuretics & BBs
- ACE-Is & BBs
- Renin inhibitors & diuretics
- Renin inhibitors & ACE-Is/ARBs
What is NOT recommended (& potentially harmful) for those w/ elevated BP or HTN?
Simultaneous use of ACE-I, ARB, & renin inhibitor
What is a “strong” recommendation regarding BP goal?
Adults w/ HTN & known CVD or 10yr ASCVD risk of 10% or higher = 130/80
What is a “weak” recommendation regarding BP goal?
Adults w/ HTN w/out increased CVD risk = 130/80 (may be REASONABLE)
What is recommended for initial therapy?
First line agents = thiazides, CCBs, & ACE-Is or ARBs
What is recommended tx for HTN w/ SIHD?
Meds for compelling indications as first line therapy, w/ addition of other drugs as needed
What GDMT beta blockers should be used for BP control or relief of angina? Which should not?
Carvedilol, metoprolol tartrate, metoprolol succinate, nadolol, bisoprolol, propranolol, & timolol
- Avoid those w/ intrinsic sympathomimetic activity
- Atenolol should not be used bc it is less successful than placebo at reducing CV events
In pts w/ HFrEF, what tx for HTN is considered to have no benefit?
Non-DHP CCBs
In pts w/ acute ICH, what is considered harmful tx?
Lowering SBP less than 140 in those who present within 6 hrs & have a SBP btwn 150 & 220
In pts w/ PAD, what is the recommended tx?
Treat similarly to those w/out PAD
What is a “weak” recommendation for tx of AF?
ARB can be useful for prevention of reoccurrence
In pts w/ asx aortic stenosis, what is a strong recommendation for tx of HTN?
Start at low dose & gradually titrate upward as needed
In pts w/ chronic aortic stenosis, what is a weak recommendation for tx of systolic HTN?
It is reasonable to treat w/ agents that do not slow HR (avoid beta blockers)
In aortic dz, what is a strong recommendation for tx of HTN?
Beta blockers
What is considered a “weak” recommendation for pts w/ cognitive decline or dementia & HTN?
BP lowering is reasonable
