Kamal, Ayeesha Kamran

Siddiqi, Shaista Anwar

eCommons@AKU

eCommons@AKUDepartment of Medicine Department of MedicineDecember 2011Ambulatory blood pressure monitoring in strokesurvivors: what do we add to the care of ourpatients?Shaista Anwar SiddiqiAga Khan UniversityAyeesha Kamran KamalAgha Khan University, ayeesha.kamal@aku.eduFollow this and additional works at: http://ecommons.aku.edu/pakistan_fhs_mc_med_medPart of the Neurology CommonsRecommended CitationSiddiqi, S. A., Kamal, A. (2011). Ambulatory blood pressure monitoring in stroke survivors: what do we add to the care of ourpatients?. JPMA. The Journal of the Pakistan Medical Association, 61(2), 1250-1251.Available at: http://ecommons.aku.edu/pakistan_fhs_mc_med_med/377Vol. 61, No. 12, December 2011 1250Ambulatory blood pressure monitoring in stroke survivors: What dowe add to the care of our patients?Shaista Anwar Siddiqi, Ayeesha Kamran KamalStroke Service, Section of Neurology, Depart,emt of Medicine, Aga Khan University Hospital, Karachi , Pakistan.Evidence Based MedicineWhy is it necessary to know about thecircadian blood pressure rhythm in acutestroke patients?Hypertension is a major reversible risk factor forstroke in all age groups. The biphasic circadian bloodpressure (BP) pattern with physiological nocturnal decreaseof 10-15 % in the BP is referred to as "Dipping". Thisrhythm is lost in chronic hypertension and stroke.Absence of normal dipping results in a higher 24hour blood pressure load and may lead to more target organdamage like left ventricular hypertrophy or recurrent stroke.Moreover, sleep systolic and early morning systolic BP(SBP) are more predictive for stroke events than daytimeSBP, especially in the elderly.Conventional BP recordings may therefore beinadequate to delineate these changes in physiology.Ambulatory blood pressure monitoring (ABPM) has beenintroduced as a reliable method of obtaining an accurateclinical assessment especially in hypertensive strokepatients. What do we know about the circadian rhythmof BP in stroke patients?Limited data is available addressing the circadianrhythm in acute stroke patients. Luis et al evaluated thelong term changes of BP in Spanish stroke survivors usingABPM and compared them with the conventional clinicmeasurements. They studied 101 consecutive patients (62males and 39 females; mean age: 71 years; 88 ischaemicand 13 haemorrhagic strokes) coming to their hospitalwithin 24 hours of acute stroke. The BP was automaticallyrecorded for 24 hours for every 15 minutes during thedaytime (7.00 am-11 pm) and every 30 min at night (11 pmto 7 am). Patients were classified according to thepercentage fall in mean SBP at night compared to duringthe day as: dippers (fall 10-20%); extreme dippers(>20%); non-dipper (<10%); and reverse dippers i.e. a risein mean nocturnal SBP compared to mean daytime SBP.These patients were followed up for the changes in the BPcircadian rhythm through outpatient visits with ABPM at 6and 12 months after discharge. Manual BP was measuredwith a standard manual sphygmomanometer at the timethat 24-hour ABPM was performed according to thecurrent recommendations. For manual BP, each value wastaken as the average of three readings taken 1 minuteapart. Interestingly, the percentages of abnormal circadianrhythm of SBP after stroke were similar in bothhypertensive and non-hypertensive patients. There weresignificant differences in the mean systolic and diastolicBP by the conventional sphygmomanometer versusABPM. The reading was higher for the former. There weremore non dipping as well as reverse dipping patternobserved in the stroke survivors. The West Birmingham Stroke Project alsoinvestigated the clinical use of a 24-hour oscillometricABPM device in patients after acute stroke within 12hours of onset. A total of 86 patients (48 men; mean age 64years) with either Transient Ischaemic Attacks (TIA) orstroke were included. BP was measured using bothconventional method and by ABPM. The first readingobtained with the ABPM device was compared withsimultaneous manual BP measurements. Mean daytimeand nighttime pressures were also analysed to determinethe frequency of dipping. Higher systolic BP was recordedby ABPM (but not manually) in patients with IntracerebralHaemorrhage (ICH) as compared to cerebral infarcts. Asimilar trend of higher SBP was seen in blacks. Patientswith stroke demonstrated a loss of diurnal BP rhythm. Inaddition to this, a trend toward reverse dipping was seen inpatients with ICH.What is the effect of circadian rhythm onfunctional outcome in stroke?Another group assessed the influence of 24 hourBP levels on functional recovery a week after strokeand the effect of antihypertensive therapy on 24 hourBP levels. Out of 160 stroke admissions, 72 patientsadmitted to hospital within 24 hours of stroke onsetwere investigated. Casual supine BP was measured in thehemiparetic arm on three occasions with a standardmercury sphygmomanometer to obtain a mean BPreading. A 24 hour BP measurement were performedimmediately thereafter using Dyna Pulse 5000 Arecorder, programmed to record BP at 30- min intervalsduring the day (7 am-10pm) and during the night (10 pm-7 am). The mean difference between mean casual and24 hour ABPM for SBP and Diabetic Blood Pressure(DBP) was 4.7 mmHg and 5 mmHg respectively. Blackshad a higher mean 24 hour, day and night DBP thanwhites. The mean drop in day-night DBP that is dippingwas lower in non-lacunar strokes. For each 10 mmHgdifference between day and night time DBP within 24hour of stroke onset, the odds for complete functionalrecovery were fourfold. A lack of nocturnal dipping wasassociated with poor outcome.What are these studies teaching us?Survivors of stroke, both hypertensive and non-hypertensive patients, present a chronic disruption ofcircadian rhythm of BP which can vary with the stroke type.Modest promotion of nocturnal BP dipping and preservationof the physiological circadian pattern of BP may induce aprotective effect on cerebral circulation among patients withischaemic stroke. However, the value of tentative loweringof BP to maintain the physiological dipping phenomenaafter acute stroke has yet to be addressed in largerandomized controlled trials.Suggested Reading1. Guerra LC, Moreno MCF, Montoro AE, Chozas JML. Ambulatory bloodpressure monitoring in stroke survivors: Do we really control our patients?Eur J Intern Med 2009; 20: 760-3.2. Jain S, Namboodri KKN, Kumari S, Prabhakar S. Loss of circadian rhythm ofblood pressure following acute stroke. BMC Neurol 2004; 4.3. Bhalla A, Wolfe CDA, Rudd AG. The effect of 24 h blood pressure levels onearly neurological recovery after stroke. J Intern Med 2001; 250: 121-30.1251 J Pak Med Assoc

English

Ambulatory blood pressure monitoring in stroke survivors: what do we add to the care of our patients?

eCommons@AKUSection of Neurology Department of MedicineDecember 2011Ambulatory blood pressure monitoring in strokesurvivors: what do we add to the care of ourpatientsShaista Anwar SiddiqiAga Khan UniversityAyeesha Kamran KamalAga Khan UniversityFollow this and additional works at: http://ecommons.aku.edu/pakistan_fhs_mc_med_neurolPart of the Neurology CommonsRecommended CitationSiddiqi, S., Kamal, A. (2011). Ambulatory blood pressure monitoring in stroke survivors: what do we add to the care of our patients.Journal of the Pakistan Medical Association, 61(12), 1250-1.Available at: http://ecommons.aku.edu/pakistan_fhs_mc_med_neurol/8Vol. 61, No. 12, December 2011 1250Ambulatory blood pressure monitoring in stroke survivors: What dowe add to the care of our patients?Shaista Anwar Siddiqi, Ayeesha Kamran KamalStroke Service, Section of Neurology, Depart,emt of Medicine, Aga Khan University Hospital, Karachi , Pakistan.Evidence Based MedicineWhy is it necessary to know about thecircadian blood pressure rhythm in acutestroke patients?Hypertension is a major reversible risk factor forstroke in all age groups. The biphasic circadian bloodpressure (BP) pattern with physiological nocturnal decreaseof 10-15 % in the BP is referred to as "Dipping". Thisrhythm is lost in chronic hypertension and stroke.Absence of normal dipping results in a higher 24hour blood pressure load and may lead to more target organdamage like left ventricular hypertrophy or recurrent stroke.Moreover, sleep systolic and early morning systolic BP(SBP) are more predictive for stroke events than daytimeSBP, especially in the elderly.Conventional BP recordings may therefore beinadequate to delineate these changes in physiology.Ambulatory blood pressure monitoring (ABPM) has beenintroduced as a reliable method of obtaining an accurateclinical assessment especially in hypertensive strokepatients. What do we know about the circadian rhythmof BP in stroke patients?Limited data is available addressing the circadianrhythm in acute stroke patients. Luis et al evaluated thelong term changes of BP in Spanish stroke survivors usingABPM and compared them with the conventional clinicmeasurements. They studied 101 consecutive patients (62males and 39 females; mean age: 71 years; 88 ischaemicand 13 haemorrhagic strokes) coming to their hospitalwithin 24 hours of acute stroke. The BP was automaticallyrecorded for 24 hours for every 15 minutes during thedaytime (7.00 am-11 pm) and every 30 min at night (11 pmto 7 am). Patients were classified according to thepercentage fall in mean SBP at night compared to duringthe day as: dippers (fall 10-20%); extreme dippers(>20%); non-dipper (<10%); and reverse dippers i.e. a risein mean nocturnal SBP compared to mean daytime SBP.These patients were followed up for the changes in the BPcircadian rhythm through outpatient visits with ABPM at 6and 12 months after discharge. Manual BP was measuredwith a standard manual sphygmomanometer at the timethat 24-hour ABPM was performed according to thecurrent recommendations. For manual BP, each value wastaken as the average of three readings taken 1 minuteapart. Interestingly, the percentages of abnormal circadianrhythm of SBP after stroke were similar in bothhypertensive and non-hypertensive patients. There weresignificant differences in the mean systolic and diastolicBP by the conventional sphygmomanometer versusABPM. The reading was higher for the former. There weremore non dipping as well as reverse dipping patternobserved in the stroke survivors. The West Birmingham Stroke Project alsoinvestigated the clinical use of a 24-hour oscillometricABPM device in patients after acute stroke within 12hours of onset. A total of 86 patients (48 men; mean age 64years) with either Transient Ischaemic Attacks (TIA) orstroke were included. BP was measured using bothconventional method and by ABPM. The first readingobtained with the ABPM device was compared withsimultaneous manual BP measurements. Mean daytimeand nighttime pressures were also analysed to determinethe frequency of dipping. Higher systolic BP was recordedby ABPM (but not manually) in patients with IntracerebralHaemorrhage (ICH) as compared to cerebral infarcts. Asimilar trend of higher SBP was seen in blacks. Patientswith stroke demonstrated a loss of diurnal BP rhythm. Inaddition to this, a trend toward reverse dipping was seen inpatients with ICH.What is the effect of circadian rhythm onfunctional outcome in stroke?Another group assessed the influence of 24 hourBP levels on functional recovery a week after strokeand the effect of antihypertensive therapy on 24 hourBP levels. Out of 160 stroke admissions, 72 patientsadmitted to hospital within 24 hours of stroke onsetwere investigated. Casual supine BP was measured in thehemiparetic arm on three occasions with a standardmercury sphygmomanometer to obtain a mean BPreading. A 24 hour BP measurement were performedimmediately thereafter using Dyna Pulse 5000 Arecorder, programmed to record BP at 30- min intervalsduring the day (7 am-10pm) and during the night (10 pm-7 am). The mean difference between mean casual and24 hour ABPM for SBP and Diabetic Blood Pressure(DBP) was 4.7 mmHg and 5 mmHg respectively. Blackshad a higher mean 24 hour, day and night DBP thanwhites. The mean drop in day-night DBP that is dippingwas lower in non-lacunar strokes. For each 10 mmHgdifference between day and night time DBP within 24hour of stroke onset, the odds for complete functionalrecovery were fourfold. A lack of nocturnal dipping wasassociated with poor outcome.What are these studies teaching us?Survivors of stroke, both hypertensive and non-hypertensive patients, present a chronic disruption ofcircadian rhythm of BP which can vary with the stroke type.Modest promotion of nocturnal BP dipping and preservationof the physiological circadian pattern of BP may induce aprotective effect on cerebral circulation among patients withischaemic stroke. However, the value of tentative loweringof BP to maintain the physiological dipping phenomenaafter acute stroke has yet to be addressed in largerandomized controlled trials.Suggested Reading1. Guerra LC, Moreno MCF, Montoro AE, Chozas JML. Ambulatory bloodpressure monitoring in stroke survivors: Do we really control our patients?Eur J Intern Med 2009; 20: 760-3.2. Jain S, Namboodri KKN, Kumari S, Prabhakar S. Loss of circadian rhythm ofblood pressure following acute stroke. BMC Neurol 2004; 4.3. Bhalla A, Wolfe CDA, Rudd AG. The effect of 24 h blood pressure levels onearly neurological recovery after stroke. J Intern Med 2001; 250: 121-30.1251 J Pak Med Assoc

Ambulatory blood pressure monitoring in stroke survivors: what do we add to the care of our patients

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Ambulatory blood pressure monitoring in stroke survivors: what do we add to the care of our patients

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