Comanaging pressures: Kidney Week experts advise on hypertension

Certain specialized circumstances can make high blood pressure particularly problematic.

“We've all had that call that our patient is in the preoperative area. Their blood pressure is 190,” said cardiologist and ACP Member John Bisognano, MD, PhD. “The surgeon is mad. The anesthesiologist is enraged...we're feeling that pressure that we have to get that patient to the operating room.”

Surgeons aren't the only specialists likely to call on internist colleagues for help with hypertension. At the American Society of Nephrology's annual Kidney Week conference (held in Philadelphia last November), Dr. Bisognano was one of several speakers addressing issues of hypertension in hospitalized patients.

Almost half of all inpatients have pre-existing hypertension, noted Dr. Bisognano, who is a professor of medicine at the University of Rochester Medical Center in New York. But certain specialized circumstances—including surgery, stroke and pregnancy—can make high blood pressure particularly problematic.

Evidence on how to treat these patients is limited in most cases, but the experts offered their best advice on how to handle these high-pressure situations.

Perioperative pressure

Ideally, the management of a perioperative patient's hypertension should start long before the urgent call from the operating room.

“The most common reason their blood pressure at the time of the operation is irregular is because they haven't taken their medications, or the medications they were given in the hospital are different,” said Dr. Bisognano. “The most important thing we could do is make some judgment regarding which blood pressure medications they should be on during that day and be very clear to them about which ones they need to take.”

Beta-blockers should be continued, and even added if the patient is high risk, he recommended. “It's probably best to hold ACE inhibitors and ARBs during the perioperative period,” Dr. Bisognano said.

Beta-blockers can also be helpful with another common cause of preoperative hypertension—nerves. “Patients have white coat hypertension in office visits. If we think we're bad to see, the patients really don't want to see a surgeon,” said Dr. Bisognano. Anxiolytics can also be used.

But hospitalists still need to carefully assess these patients, he noted. “Our job is to separate patients who truly have accelerated hypertension who may have an adverse event during the operation or after the operation from somebody who's just a little bit nervous.”

Unfortunately, there are no definitive cutoffs for when hypertension is dangerous in a perioperative patient. “Generally speaking, hypertensive emergencies that we see in the emergency room and other areas of the hospital have a diastolic blood pressure of 140, but we all know that can be much lower,” said Dr. Bisognano.

The blood pressure at which surgeons and anesthesiologists are comfortable proceeding with an operation may be substantially lower. “Hypertension makes them nervous. They're told that anything over 180 is a potential disaster. They may be right. They remember the patients who've gotten strokes,” said Dr. Bisognano. “The time to educate your colleagues is not in the preoperative area.”

Cardiac and vascular surgeons, in particular, may also have strong opinions about the patient's target postoperative blood pressure. “We're used to big numbers in blood pressure but for a vascular patient, a blood pressure of 180 may be the end of the world,” he said. “Those new suture lines are being threatened.”

In general, postoperative hypertension management may be even more complicated than the preop variety. Volume status can be very variable. “Some of them inadvertently get that extra liter in the postoperative state and they come to you massively volume overloaded. Those are patients who may need a diuretic,” said Dr. Bisognano.

Insufficiently treated pain can also cause hypertension. “They need adequate analgesia postoperatively and treating their blood pressure may be as simple as that,” he said.

Other patients may be feeling the effects of changes in their medication regimens. “Many patients are on clonidine. They will get a brisk withdrawal. They probably need it back,” said Dr. Bisognano.

For patients whose problems can't be resolved so simply, however, physicians will have to decide how and how much to treat. “You want to reduce the mean arterial pressure by about 20% to 25%, to about 110 to 120 mm Hg, over two to four hours. Don't rush it,” Dr. Bisognano advised.

Hypertensive emergencies should be treated with intravenous medications. A standard choice is nitroprusside, but the drug has some limitations. “Even though pharmacologically it's the quickest-acting, from an administration standpoint it seems to me there's an always an hour delay,” he said. Administration requires an arterial line and an aluminum foil bag, and many nurses have little experience with it.

Nitroglycerine is a potential alternative. “It will buy you a few hours,” said Dr. Bisognano. “Most nursing staff is comfortable using it. It will drop their blood pressure by 10 to 30 points depending on how much you give.”

Esmolol is an expensive alternative, but Dr. Bisognano generally prefers 20-mg doses of another beta-blocker. “My favorite drug for the immediate drop in blood pressure is labetalol,” he said. Nicardipine is another good choice, but nifedipine capsules should definitely not be used, based on warnings from the FDA.

After immediate hypertensive emergencies or urgencies are resolved, the goal should be to transition patients to oral antihypertensives. “Many patients undergoing surgery haven't seen a doctor in a while and this may be a great opportunity to get them on a good long-acting blood pressure medication,” Dr. Bisognano said. (Long-acting medications can be trouble in hypertension emergencies, however, he noted. “Try not to use medications that are absorbed hours after you give them because you may drop 25% and then when the patient's asleep, they drop another 50%.”)

Oral beta-blockers, calcium-channel blockers and diuretics may all be appropriate choices to get postop patients' blood pressure to a level reasonable for discharge. “It'll decrease your length of stay, get your patient out of the hospital, and perhaps for one of the first times in their life, they'll actually have their blood pressure treated to a reasonable level,” Dr. Bisognano concluded.

Neurology and hypertension

Neurology patients have also often had high blood pressure of long duration, conference attendees were told by Venkatesh Aiyagari, MBBS, associate professor of neurology at University of Illinois College of Medicine at Chicago.

“We all know that hypertension is the major risk factor for stroke,” he said. Inpatient hypertension is also an indicator of worse outcomes in a variety of neurological patients, according to a registry study published in Critical Care Medicine last October.

“Compared to non-neurology patients, neurology patients with high blood pressure—that is, high enough to require IV antihypertensive treatment—had double the hospital length of stay, a fourfold higher 90-day mortality, and a sixfold higher in-hospital mortality,” reported Dr. Aiyagari.

In the long term, treating hypertension clearly benefits patients with stroke, he said. Despite this, the question of whether to treat stroke patients' hypertension in the acute stage is complicated. “Most neurologists have had the experience of a patient that's had their blood pressure lowered and suddenly has had their stroke symptoms worsen,” he explained.

Specifically, in ischemic stroke patients, lowering blood pressure has generally been found to be unhelpful, although most data come from small trials. And there's an exception: Patients who are receiving tissue plasminogen activator have a higher risk of hemorrhagic transformation if they have high blood pressure.

Dr. Aiyagari summed up the situation. “If the patient is a thrombolysis candidate, we lower the blood pressure. If the patient is not a thrombolysis candidate, if the blood pressure is extremely high, or there are other compelling reasons, you can consider lowering. In all other cases, it's better to avoid lowering blood pressure for the first week.”

According to American Heart Association (AHA) recommendations, the cutoff for that extremely high pressure is 220 mm Hg systolic, but Dr. Aiyagari expressed uncertainty about the evidence for that limit. “As the patient's blood pressure keeps going higher and higher, the physician starts feeling more and more distressed until they reach a point when the physician's distress score reaches a magic number,” he said. “That's when the trigger is pulled, and boom, the patient is treated.”

In the patients whose hypertension you decide to treat, proceed slowly, he advised. “If you want to lower blood pressure, better to stick, at least on day one, with less than 10%.”

Hemorrhagic strokes raise complications of their own. The AHA recommendations suggest treatment at 160 mm Hg systolic. “The risk of lowering blood pressure seems much less than that of ischemic stroke,” said Dr. Aiyagari.

For patients with intracerebral hemorrhage, the limited existing data don't show much benefit of antihypertensives on mortality or outcomes, but there might be a marginal effect on hematoma expansion, he reported. Lowering blood pressure “is probably safe, provided intracranial pressure [ICP] is not really high,” Dr. Aiyagari added. “Put in an intracranial pressure monitor so you know what the cerebral perfusion pressure [CPP] is, especially in patients with big bleeds.”

Treatment of subarachnoid hemorrhages is supported by even less data, but some standard practices exist. “Usually prior to definite treatment of the aneurysm, most surgeons would like to keep the blood pressure low to prevent aneurysm rebleeding. Once the aneurysm has been secured, either with a clip or a coil, usually blood pressure control is liberalized. If these patients go into vasospasm, we actually treat them by raising their blood pressure, often to very high systolic levels,” he said.

Although there are also some standard approaches to hypertension in head injury patients, they differ regionally. “In North America, most physicians follow CPP-targeted therapy, where we aim to keep the CPP above 60 mm mercury. In some Scandinavian countries, their main goal is to keep the ICP low and they actually allow the CPP to be as low as 50,” Dr. Aiyagari said. “Again, there are no randomized trials comparing these.”

Hypertensive for two

A dearth of randomized trials is also an issue with hypertension in hospitalized pregnant women. And that's not the only problem. “It's a clinical area that usually strikes fear in the hearts of most internists and nephrologists mainly because the stakes are so high,” said ACP Member Phyllis August, MD, a professor of medicine in obstetrics and gynecology at Weill Cornell Medical College in New York.

The first challenge in treating an obstetric patient's blood pressure is determining whether it's chronic or gestational hypertension or pre-eclampsia. (“Gestational hypertension is simply pregnancy-associated hypertension without the laboratory manifestations of pre-eclampsia, although 20% of these women do develop pre-eclampsia if they stay pregnant long enough,” noted Dr. August.)

One helpful clue is gestational age, but “it's not foolproof,” Dr. August warned. “Less than 20 weeks is usually chronic hypertension, either primary or secondary. After 20 weeks, all bets are off.”

Lab tests, including urinalysis, serum creatinine, and possibly serum complements, can be used to pin down a diagnosis. “Having normal labs and being multiparous—because pre-eclampsia is more common in primiparous women—is more suggestive of a chronic or gestational hypertension,” said Dr. August.

A patient's history, specifically her previous blood pressures, may guide the course of treatment. “Did she start out at 90/60? If so, you'd be more aggressive….My target is somewhere between 130 and 150. I'm uncomfortable seeing the blood pressure greater than 150, especially in a previously normotensive woman,” Dr. August said, noting that historic recommendations have been much higher. “If you look at an older obstetrics textbook, you might be a little uneasy….Many of the guidelines are adjusting the levels downward from 170-180 to 160.”

One of the motivators of this downward trend has been the upward trend in pregnant women's ages, because older women have more comorbidities and complications. Symptoms can also make treatment necessary at a lower number. “Usually when there are symptoms—headache, visual disturbances, epigastric pain—that you think are related to this process, that's usually considered an indication for treatment,” she said.

Treatment should proceed slowly (“The obstetricians are concerned about lowering the blood pressure too much,” said Dr. August) and be chosen from a limited list. “Renin-angiotensin-aldosterone system [RAAS] blockers are contraindicated at all times,” she said.

For patients who need quick-acting treatment because they have symptoms or will be delivering soon, there are a few intravenous choices. Labetalol is a top choice, followed by hydralazine, which has a few more adverse maternal side effects, Dr. August noted. There have been some reports of use of nicardipine, and nifedipine is an option although it can cause headaches, which can be confusing, since that's a sign of hypertensive trouble.

“If you have more time with respect to delivery, if the patient is asymptomatic, you can use oral agents,” Dr. August said. “Control the blood pressure the best way you can with drugs that you're comfortable using.”

But don't get too comfortable having treated a woman's antepartum hypertension and forget about postpartum problems. “The baby is delivered so you say, ‘OK, we're in good shape’ but this is a period where bad things can still happen,” she said.

Most cerebrovascular catastrophes surrounding pregnancy occur postpartum, and blood pressure is actually higher in most women—both hypertensive and normotensive—in the week after delivery than it was before.

The potential causes of this hypertension are varied, including volume status, withdrawal of vasodilating factors and ibuprofen. “The obstetricians are using this in buckets, huge doses, for peripartum analgesia,” Dr. August said.

Discontinuing these medications, minimizing fluids and using diuretics are acceptable treatments. “Diuretics can reduce breast milk, so you have to be careful about that,” she said. In general, the drugs that are safe during pregnancy are the same ones that are appropriate for breast-feeding mothers.

To determine the duration of therapy, send the patients home with a blood pressure monitor. “We ask them to check their blood pressure frequently, because not only can it go up, it can go down suddenly,” said Dr. August. Unfortunately, there are no guidelines regarding management of postpartum hypertension.

“How do we manage these women?” she asked rhetorically. “Common sense, good clinical practice.”