HY lecture notes:
Best way to decrease mortality overall –> smoking cessation.
Best way to decrease stroke, TIA, central retinal artery occlusion risk –> HTN control.
72M smoker with BP of 155/90 has stroke, TIA, central retinal artery occlusion; best way to decrease recurrence? –> answer = lisinopril, not smoking cessation (HY). This is because emboli from carotid plaques are responsible for most strokes in patients with HTN. Even though smoking is big risk factor for atherosclerosis, when it comes to the carotid arteries specifically, the systolic impulse of HTN is more causative of the plaques.
Best way to decrease stroke in patient with AF + HTN? –> Tx of the AF > Tx of the HTN.
Best way to decrease BP –> weight loss, not smoking cessation.
Best way to decrease type II diabetes risk –> weight loss, not smoking cessation.
Best way to decrease type II diabetes risk (choose between “low-calorie diet” or “low-carbohydrate diet”) –> answer = low-calorie diet –> as long as BMI is in the normal range, type II diabetes risk is reduced.
Best way to decrease complications of diabetes –> good glycemic control, not smoking cessation.
Best way to decrease risk of MI –> smoking cessation.
Most common risk factor for atherosclerosis –> HTN.
Most acceleratory (worst) risk factor for atherosclerosis –> FIRST diabetes (I or II; doesn’t matter), THEN SECOND smoking. HTN is most common risk factor across the population, but of those who are diabetic and/or smokers, they develop atherosclerotic disease much faster. If the FM Q gives you a patient who is both a smoker + has HTN, choose smoking cessation as more important in that patient to decrease atherosclerotic risk.
Most common cause of carotid plaques? –> HTN –> the strong systolic impulse from the heart pounds the carotids –> endothelial damage –> atherosclerosis.
55M + BP 150/90 + TIA; next best step in Mx? –> carotid duplex USS –> the first thing you want to think about is, “does this guy have a carotid plaque that has resulted in a clot embolizing to his brain.”
80M + good blood pressure (e.g., 110/70) + stroke or TIA; next best step in Mx? –> ECG –> you want to think, “Does he have atrial fibrillation with a LA mural thrombus that’s now embolized to the brain.”
80M + good blood pressure (e.g., 110/70) + stroke or TIA + ECG shows sinus rhythm with no abnormalities; next best step in Mx? –> Holter monitor –> when you first see this scenario you’re probably like, “Wait, the ECG is normal, so it’s not AF?” –> No, it is likely AF, but AF is often paroxysmal, so in order to detect it in this scenario, the next best step is a Holter monitor (24-hour wearable ECG). This means that later in the day when he sits down to have dinner and then pops into AF, the Holter monitor will pick it up.
What % of people over age 80 have AF? –> 8% of people over age 80 have AF, which is why age is a huge risk factor. In other words, if the vignette says the guy is 58, AF is probably less likely just based on shear probability, regardless of hypertensive status.” And, once again, knowing that AF is often paroxysmal is really important.
Age 50s-60s + high BP + TIA/stroke/retinal artery occlusion; next best step in Dx? –> answer = carotid duplex ultrasound to look for carotid plaques.
Age >75 + good BP + TIA/stroke/retinal artery occlusion; answer = ECG to look for AF –> if normal, do Holter monitor to pick up paroxysmal AF.
55M + good BP + carotid bruit heard on auscultation; next best step in Mx? –> answer = carotid duplex ultrasound to look for carotid plaques –> in this case, if they are obvious and explicit about the suspected etiology of the stroke, TIA, or retinal artery occlusion, then you can just do the carotid duplex ultrasound.
How to Mx carotid plaques? –> first we have to ask whether the patient is symptomatic or asymptomatic. A bruit does not count as symptoms (that’s a sign). Symptomatic means stroke, TIA, or retinal artery occlusion. According to recent guidelines: carotid occlusion >70% if symptomatic, or >80% if asymptomatic –> answer = do carotid endarterectomy. Below these thresholds –> answer = medical management = statin, PLUS clopidogrel OR dipyridamole + aspirin. The USMLE will actually not be hyper-pedantic about the occlusion %s (that’s Qbank). They’ll make it obvious for you which answer they want. They’ll say either 90% –> answer certainly = carotid endarterectomy, or they’ll say 50% à answer = medical management only. There’s one NBME Q where they say a guy has a bruit but is asymptomatic, and has 10 and 30% occlusion in the left vs right carotids, respectively, and he’s already on aspirin + statin, and the answer is “maintain current regimen” –> if he were symptomatic, even with low occlusion, he’d certainly need statin, PLUS clopidogrel OR dipyridamole + aspirin.
How to Tx AF? –> we have to consider both arms of management: blood thinning + treating the actual AF. For blood thinning, CHADS2 score is standard in terms of evaluating risk (there are variants, but the USMLE won’t ever be borderline with how this plays into a question; they’ll either give you a full-blown obvious high-risk patient where all are positive, or they’ll make it clear that the patient is low-risk and merely just has AF alone).
CHADS2 = CHF, HTN, Age 75+, Diabetes, Stroke/TIA (latter is 2 points; the rest are 1 point).
If 0 or 1 points, give aspirin (anti-platelet therapy).
If 2+ points, give warfarin (anti-coagulation therapy).
If valvular AF (i.e., AF in someone with a mitral or aortic valve lesion), answer = warfarin.
If non-valvular AF, can give other agents (e.g., dabigatran, apixaban).
For the actual Tx of the AF, we do rate control before rhythm control (the management is actually heavily involved, but for the USMLE know the following):
Rate control: beta-blocker first-line (metoprolol). If beta-blocker avoided (i.e., severe or psychotic depression, sexual dysfunction, COPD, Hx of asthma requiring oxygen or hospitalization, 2nd/3rd-degree heart block), verapamil is the next choice. If rate control fails, go to rhythm control.
Rhythm control: Flecainide (type-Ic Na channel blocker) first-line in those without any structural (i.e., LVH or valvular problems) or coronary artery disease (any symptomatology of CVD or PVD means patient has coronary artery disease). In those who cannot receive flecainide, other anti-arrhythmics like amiodarone, dronedarone, and dofetilide may be used.
