Blood Pressure

Jan 30

Hypertension (HTN)

Okay let me put my cards on the table, I have started to write about this medical subject several times just to fall down a rabbit hole. Topic is almost too big to know where to start. As a doctor of function, let me start there. The principle system is a muscular cyclical pump coupled with a series of elastic tubes (aorta, arteries etc.). The design principle is that these two components must be matched. The pump ejects what is called a stroke volume and the elastic tube swells to accept the volume. The net effect downstream is continuous blood flow, not stop-go. So the natural properties of the elastic tubes is to stiffen overtime. This means the pressure in the tube rises higher to accept the same squirt of blood, as you age. This climbing number is often expressed as your age plus 100 as a common blood pressure, common does not mean normal. Where science draws the boundary line then defines the disease categories. As I will show below, big Pharma has a big stake in the game (and this is the first rabbit hole). Stricter treatment guidelines lead to more drug sales. It is estimated that (based on current guidelines) approximately 1 in 3 Americans has hypertension (HTN) and 5 of the top 20 prescription drugs (Rx) treat HTN.

Top 20 Rx Drugs

1.     Lisinopril (Prinivil, Zestril) ($4)
2.    Atorvastatin (Lipitor) ($15)
3.    Levothyroxine (Synthroid) ($4)
4.    Metformin Hydrochloride (Glucophage) ($4)
5.    Amlodipine (Norvasc) ($9)
6.    Metoprolol (Toprol, Lopressor) ($4)
7.    Omeprazole (Prilosec) ($15)
8.    Simvastatin (Zocor) ($9)
9.    Losartan Potassium (Cozaar) ($9)
10. Albuterol (Proventil, Ventolin)
11. Gabapentin (Neurontin)
12. Hydrochlorothiazide (HCTZ) ($4)
13. Acetaminophen; Hydrocodone Bitartrate (CO-gesic, Lorcet-HD, Vicodin, Lortab)
14. Sertraline (Zoloft) ($9)
15. Fluticasone (Flonase)
16. Montelukast (Singulair)
17. Furosemide (Lasix) ($4)
18. Amoxicillin
19. Pantoprazole Sodium (Protonix)
20. Escitalopram Oxalate (Lexapro) ($9)

Blood Pressure (1,5,6,9,12, +/- 17), Cholesterol (2, 8), Stomach Acid (7, 19), Breathing, Allergies (10, 15, 16), Pain (11, 13), Depression (14, 20), Three areas with one drug each, thyroid replacement, diabetes, antibiotic

A couple of important points: First, generics are cheaper, the same medication, and when available are always the preferred choice for cost savings. Walmart used to have drug list of $4 Rx, their current list effective 11/4/2019 has $4/$9/$15 categories per month which correlates to $10/$24/$38 for 90 day supply. 13 of top 20 listed above are on the Walmart list:

https://i5.walmartimages.com/dfw/4ff9c6c9-1a4c/k2-_f9b4b995-c89b-4ee4-9965-b8bcc77eb08d.v1.pdf

Second rabbit hole, Cardiologists are among the top prescribers of Rx meds with the problems of Blood Pressure, Cholesterol and HeartBurn being behind 10 of the top 20. In the past I have been a frequent prescriber of 19 out of the 20 with only the narcotic containing Rx (#13) being used rarely. The points I am trying to bring together are that the faster/more expensive route of treating a number with a pill, needs to be replaced with some leniency on number goals and frankly a more holistic approach to the problem

First some simple comments on the numbers. Back in the old days we had one number 140/90. Has the bar been lower from this point? Old guideline dated 2003 used 140/90, revised guideline 2017 lowered to 130/80. My experience is that patients with the most abnormal blood pressures get the most treatment benefit. The less severe the BP abnormality the less treatment benefit but with equal treatment side effects. So in borderline patient groups, the treatment wording in commercials often uses phrases like “treatment should be considered”, “ask your physician”. The unfortunate truth is that we are a market society, and frankly people sort of want to take pills. In a patient encounter, it is a fast pleasant response “sure I will send that script to the pharmacy”, ”if you have any questions ask the nurse on your way out”. Win/win, patient gives 5 out of 5 rating, encounter ends quickly so doctor can move on to the next patient. If that is what occurs, stay with the older 140/90 values.

If however the 130/80 threshold is not a start a pill time, but stop and take 15 minutes in a clinical encounter to look for other problems. The simple answer is that the sooner we treat the other problems that may be impacting the blood pressure the better. Simple examples are: Smoking, Obesity, Sleep Apnea, Lack of Exercise, Poor Diet, Situational Stress, Withdrawl etc. After the co-factor is found and addressed then re-evaluate the BP.

One of the next rabbit holes I sometimes fall down involves the kidneys. In my above discussion about the passive elastic tubes which are our blood vessels, I did a major simplification. As the elastic tubes get smaller their properties are regulated by the kidneys. The kidney therefore is the control center for blood pressure. I think there two different ways to treat blood pressure, one focuses on the heart with medications like beta blockers, the second focuses on chemicals made by the kidneys (like ACE inhibitors, diuretics). All the newer treatment trials that show strong benefit use kidney focused therapy, older studies sometimes showing marginal benefit used beta blockers or drugs which had a short durations of action. Edge of the rabbit hole: so why do we send patients with elevated blood pressure first to the cardiologist as opposed to their primary care physician. The honest answer is “unwanted phone calls”. Treating blood pressure is interactive, and no busy physician looks forward to blood pressure questions. Low blood pressure, sometimes from over treatment, often requires immediate response. High blood pressure calls from frantic patients who are worried that they might have a stroke, are just nightmares. A good defense from the start, is to send this problem including the phone baggage to someone else. A second equally common approach is to over treat someone’s blood pressure initially, producing symptoms of low blood pressure (hypotension), them referring them to a specialist, to not only do the initial assessment task but to address to recent symptoms.

Okay, out from the rabbit holes, and back to a little science about blood pressure.

Arterial blood pressure is not a single number like heart rate (HR), but rather a phasic pressure change corresponding the beating/relaxing of the heart pump. The high value we call systolic blood pressure (SBP) (recorded as the heat beats) and the low value diastolic blood pressure (DBP) (in between heart beats). If the measurement reads 120 systolic and 80 diastolic, you would say, “120 over 80,” or write, “120/80 mmHg.” Blood pressure cuffs squeeze the arm to stop blood flow like a tourniquet, as the squeezing pressure is gradually lowered, blood starts to go past the obstruction. The point in which the blood first moves past is the SBP, when blood flow going past the cuff changes from intermittent to continuous is the DBP. Listening for the sounds with a stethoscope is the manual method, many machines now make the measurements automatically.

A couple important points about measuring BP. First the cuff needs to be level with the heart, which is the case when measuring BP in the upper arm of a seated patient. If the same arm is raised above the head an erroneous low reading will be measured. Also the cuff size needs to match the arm size. When a too small cuff is used with large arm, a spurious high reading is recorded. "You need to get the big thigh cuff”, might be said by the nurse when treating a large patient in which the usual arm cuffs are too small.. Second point is that blood pressure is always changing, beat to beat, and average values are more important the single measurements.

Now to summarize the guidelines:
Normal (SBP <120, DBP <80). Both 2003 and 2017 guidelines
At Risk, Pre-hypertension (SBP 120-139, DBP 80-89) 2003; Elevated (SBP 120-129, DBP <80) 2017
High Blood Pressure, HTN (SBP >140, DBP >90) 2003; HTN (SBP >130, DBP >80) 2017