New Understandings/ New Opportunities Learning Objectives Show why - - PowerPoint PPT Presentation
New Understandings/ New Opportunities Learning Objectives Show why - - PowerPoint PPT Presentation
Reassessing the Definition and Treatment of Severe Hypertension New Understandings/ New Opportunities Learning Objectives Show why the current definitions of severe HTN are 1. wrong and suggest changes Provide a working understanding
Learning Objectives
1. Show why the current definitions of severe HTN are wrong and suggest changes 2. Provide a ‘working’ understanding of the microcirculation 3. Briefly introduce old and newly acquired technologies for measuring the microcirculation 4. Convince you that this is important to you as a Cardiologist caring for the vascular health of your patients
ASSESSMENT OF SEVERE HYPERTENSION
- 1. How high is the BP (> 180/120 mmHg)?
- 2. Is there evidence of critical vascular damage in
vital organs?
AMI Pulmonary edema Hemorrhagic Stroke Hypertensive encephalopathy Dissecting aneurism Acute renal failure
PRES (RPLE)
(Posterior Reversible Encephalopathy Syndrome)
Cardinal Sx: H/A, altered LOC, seizures (generalized or focal, usually multiple including status epilepticus and can be non convulsive), focal neurological sx, particularly visual disturbances. PRES is 2- fold more common in females. Diagnosis: Clinical features + early Neuroimaging. Seen on MRI with T2 Diffusion weighted/FLAIR and DWI is the gold standard. The posterior circulation is almost always involved, but can include anterior circulation and brainstem. Also, do an EEG. ??? OCT-SD Prognosis: Potentially reversible with recognition and aggressive use
- f antihypertensive agents and anticonvulsants. However, can
progress to ischemia/hemorrhage with permanent deficits and even death if not and treated promptly and appropriately.
BERNOULLI’S PRINCIPLE (conservation of energy)
MAP = 100 Pc = 25
AUTOREGULATION OF CEREBRAL BLOOD FLOW
Mean Arterial Pressure (mmHg) CBF
60 120
STARLING EQUATION
(the convective movement of water and
small solutes across membranes)
Pfiltration = Ptransudation - Poncotic
= (Pcap - Pinterst) - (Ocap - Ointerst)
P
AReg NonReg
P/R=±F P/ ± R=F Pc ± Fc ± Pc Fc
F
AReg NonReg
P/R=±F P/ ± R=F Pc Fc Pc Fc Pc ± Fc ±
Re-setting of CEREBRAL AUTOREGULATION Time Course of this is Minutes, Up to an Hour
Mean Arterial Pressure (mmHg) CBF
60 120
AUTOREGULATION of a very abnormal Cerebral Circulation
Mean Arterial Pressure (mmHg) CBF
60 120 230
149 HTN MAP PRES MAP Baseline Delta MAP Median Delta MAP Mean 147 100 37 38 95% CI 143-150 93-106 31-45 BP equiv 205/118 (200-209/114-121) from an baseline BP
Systematic Review of All Cohort Studies and Case Reports of Hypertensive PRES 2005-2011
C+Tx C+Tx C+Tx CisP
Loss of AUTOREGULATION of Cerebral Blood Flow
Mean Arterial Pressure (mmHg) CBF
105 60 90 120
{15mmHg}
70
Reported Associations with PRES
Hypertension, sudden and severe, or not severe but significantly elevated above baseline BP Eclampsia Immunosuppressive Rx (cyclosporine, tacrolimus/sirolimus, steroids) Cytotoxic agents (cyclophosphamide, cisplatin and Pl analogues) Acute or chronic renal failure Alpha interferon, IgG, antiretroviral Rx, VEGEF inhibitors (bevacizumab) Post Vaccination for measles Lupus and other CTD TTP/HUS Erythropoetin Blood transfusions Acute Intermittent Porphyria HIV Sepsis BM transplant Hypercalcemia/hyperparathyroidism Contrast agents Stimulant abuse
149 HTN MAP PRES MAP Baseline Delta MAP Median Delta MAP Mean 147 100 37 38 95% CI 143-150 93-106 31-45 BP Equiv 205/118 (200-209/114-121) from a (N) baseline BP 37 Low BP MAP PRES MAP Baseline Delta MAP Median Delta MAP Mean 98 94 3 2 95%CI 87-103 89-99
- 8-14
BP Equiv 139/77 (131-146/73-82); baseline 5 mmHg lower
ASSESSMENT OF SEVERE HYPERTENSION
- 1. Is there evidence of critical organ damage?
- 2. Has there been a blood pressure elevation high
enough and long enough to account for that
- rgan injury?
- 3. What was the patient’s baseline BP in the days
- r weeks prior to the event?
- 4. Has the BP been poorly controlled for any
length of time in the past?
TOD for Dx of a Hypertensive Emergency
Major Criteria Supporting Evidence
Hypertensive encephalopathy/PRES Proteinuria/microalbuminuria Acute stroke - ischemic or hemorrhagic Pressure natriuresis Acute coronary syndrome Elevated urate Acute LV dysfunction/pulmonary edema Thrombocytopenia Acute aortic dissection Schistocytosis Acute renal failure Elevated LDH Pregnancy + symptoms of PRES Coagulopathy Pregnancy + HELLP syndrome Fx impairment of any other organ Pregnancy + capillary leak ( BP not req’d) Significant troponin leak Intractable bleeding Pmax, PWD, repolarzn abn on ECG Syndromes of catecholamine excess
A Severe BP Rise Should be Defined:
a) In all patients, as a persistent rise in MAP of greater than 30-45 mmHg over baseline MAP, or if baseline MAP is not known, above an MAP of 90 mmHg developing over the course of several hours to days, or a rise in MAP of 40- 60 mmHg lasting longer than 1 hour. b) In patients with sepsis/SIRS or those receiving immune modulating or cytotoxic chemotherapy that potentially impair cerebral autoregulation and/or vascular permiability, BP elevations less than these levels may similarly cause a hypertensive emergency.
c) Patients with poorly controlled hypertension with BPs above 180/120 for a period of time greater than 3 to 6 months are likely to possess adaptive structural changes in their heart and systemic vasculature that support a higher BP. These people are at particular risk of ischemic injury if the BP is rapidly lowered below autoregulatory
- limits. Thus, severe, poorly controlled hypertension is
also a Hypertensive Emergency
Long Term Outcome of Patients After a Hypertensive Microvascular Event
MacDonald et al. Am Heart J 2008; 156:91830
Meta-analysis of 5 case control and 10 cohort studies 116,175 eclamptics, 2,259, 576 controls, age < 56 yr OR of subsequent CVD including MI, stroke & CV mortality 2-fold. Also showed an increasing graded risk for severity
Bellamy et al. BMJ; doi:10.1136/bmj.39335.385301.BE
Meta-analysis of all prospective and retrospective studies 198,252 eclamptics, 3,488,160 controls, weighted mean f/u 14.7 yr OR for IHD, stroke and VTE 1.8-2.2; overall mortality 1.5 Absolute risk of IHD was 4% at 11.7yrs
DEMENTiA
How Can We Assess Whether the Microcirculation is in Trouble?
EEG, MRI Microalbuminuria Pressure Natriuresis, Uric acid INR, VWF, platelet cts, schistocytosis, lactate
P-wave dispersion, repolarization abns on the ECG, CMR
Ach- or other endothelial-mediated vasomotion Studies of the retinal microvasculature OCT-SD
Hughes AD et al. J Hypertension 2006;24:889-94