Automated Ambulatory Blood Pressure Monitoring

Number: 0025

Policy

1. Automated Ambulatory Blood Pressure Monitoring Selection Criteria

   Aetna considers automated ambulatory blood pressure monitoring medically necessary according to the selection criteria listed below, which are based, in part, on guidelines developed by the American College of Physicians.

   Note: Ambulatory blood pressure monitoring for less than 24 hours or more than 3 days is not considered medically necessary; repeat testing is not generally necessary more frequently than every 6 months.

   Member must meet any of the following criteria:

   1. Office or "white coat" hypertension:

      Ambulatory blood pressure monitoring is considered a medically necessary preventive service for screening to confirm the diagnosis of hypertension and distinguish "white coat" hypertension or a transient rise of blood pressure that occurs in the office setting. The member must have a minimum of two blood pressure readings in the office setting taken on separate days that are repeatedly elevated (systolic readings of 140 mm Hg or greater and/or diastolic readings of 90 mm Hg or greater in adults, or greater than 90th percentile for age, gender and height in children (see appendix)).

   2. Episodic hypertension:

      Ambulatory blood pressure monitoring is considered medically necessary for members whose symptomatology (paroxysms of excessive sweating, palpitations, apprehension) suggests episodic hypertension secondary to an adrenal tumor (e.g., pheochromocytoma), and office blood pressure measurements are repeatedly normal.

   3. Evaluation of hypotensive symptoms:

      Ambulatory blood pressure monitoring is considered medically necessary for members with hypotensive symptoms and/or syncopal events that are thought to be related to anti-hypertensive medications.

   4. Evaluation of syncope:

      Ambulatory blood pressure monitoring is considered medically necessary when used in conjunction with a 24-hour Holter monitor (see CPB 0019 - Holter Monitors) to determine whether symptoms of syncope or near syncope are the direct result of an arrhythmia.

   5. Nocturnal angina:

      Ambulatory blood pressure monitoring is considered medically necessary to investigate blood pressure changes in members with nocturnal angina.

   6. Resistant hypertension:

      Ambulatory blood pressure monitoring is considered medically necessary prior to instituting an invasive investigation (e.g., renin vein assays, angiogram for renal artery stenosis) for secondary causes of hypertension for members with hypertension that is refractory to medications.

2. Ambulatory Blood Pressure Monitoring Experimental Indications

   Aetna considers the use of ambulatory blood pressure monitoring experimental and investigational in any of the following situations because the medical literature does not support its use in these conditions:

   1. For blood pressure monitoring of persons with heart failure; or
   2. For blood pressure monitoring of pregnant women who do not meet any of the criteria listed above; or
   3. For diagnosing malignant (accelerated phase) hypertension. Under accepted guidelines, malignant hypertension requires urgent hospital admission for appropriate investigation and treatment; or
   4. For members with an irregular cardiac rhythm (e.g., atrial fibrillation).  Blood pressure readings are inconsistent and unreliable when an irregular cardiac rhythm is present due to variances in pulse volume; or
   5. For monitoring normal or borderline hypertensive blood pressure readings in the medical setting of members with documented evidence of end-organ damage (e.g., nephropathy, electrocardiographical changes, left ventricular hypertrophy, angina, myocardial infarction, cerebrovascular accident, transient ischemic attack) or cardiovascular risk factors (e.g., diabetes mellitus, smoking, hypercholesterolemia); or
   6. For routine monitoring to establish the clinical diagnosis of hypertension or to evaluate the member's blood pressure responses to treatment; or
   7. Routine use before initiation of continuous positive airway pressure (CPAP) therapy (i.e., performance of ABPM prior to CPAP in persons who do not have any of the medically necessary indications for ABPM listed in section I).

Background

Automated ambulatory blood pressure (BP) monitoring is an outpatient procedure using fully automated devices to measure ambulatory BP at frequent intervals during the day and night in an effort to determine the variability of a patient's BP due to environmental stresses and to aid in definitively establishing a diagnosis of hypertension before committing the patient to life-long antihypertensive therapy. 

Continuous ambulatory blood pressure (CABP) monitoring, (also known as noninvasive blood pressure monitoring [NIBP], ambulatory blood pressure monitoring [ABPM] and self-measured blood pressure monitoring [SMBP]) is a noninvasive method of measuring blood pressure (BP) over a specified period of time. Monitoring is generally done for at least 24 hours, but can be up to a maximum of three days. This is a fully automated or semi-automated device consisting of a portable battery-operated monitor worn on the hip (attached to a belt or clothing) and connected to an inflatable blood pressure cuff. The cuff will inflate at pre-set intervals (usually every 15 to 30 minutes during the day and every 30 minutes to an hour at night). The BP is then measured and recorded in the monitor where it can be retrieved for interpretation. In addition to the automatic preset readings, the semi-automated monitor can also be activated to take additional readings such as when the individual is exerting herself/himself or has symptoms of dizziness or heart racing.

CABP monitoring is utilized to evaluate individuals who are suspected of having an elevated BP only in the physician’s office (known as white coat hypertension). It has also been proposed for use in monitoring hypotension and the effectiveness of medication. CABP is also purported as a method to predict cardiovascular morbidity or mortality related to left ventricular hypertrophy and may provide useful information regarding the BP in individuals who may have chronic kidney disease, diabetes or preeclampsia. In addition, it could potentially provide the resources to capture a drop greater than 10% in nightly BP, which is called "dipping." Non-dippers are individuals who have less than a 10% decrease in their nightly BP and potentially have a higher cardiovascular mortality rate. 

Since treatment is rarely urgent in the absence of severe hypertension, the physician's diagnosis of hypertension should be substantiated first by repeated office readings by well-trained clinicians.

Patients with borderline hypertensive measurements in the office setting should have basic cardiovascular tests done.  Those who have evidence of target-organ damage or other cardiovascular risk factors should receive non-pharmacological and/or pharmacological treatments without further investigation.  Studies have unequivocally demonstrated that these patients have a significant risk of developing cardiovascular disease and will benefit from antihypertensive therapy.  Patients with no evidence of target-organ damage and no risk factors should be classified by a trial of self-measured BP; drug treatment should be considered for patients with consistently elevated readings in this setting.

The U.S. Preventive Services Task Force (2015) recommends screening for high blood pressure in adults aged 18 years or older. The USPSTF recommends obtaining measurements outside of the clinical setting for diagnostic confirmation before starting treatment. The Task Force states that ambulatory blood pressure monitoring and home blood pressure monitoring may be used to confirm a diagnosis of hypertension after initial screening. The USPSTF found convincing evidence that ambulatory blood pressure monitoring is the best method for diagnosing hypertension. Although the criteria for establishing hypertension varied across studies, there was significant discordance between the office diagnosis of hypertension and 12- and 24-hour average blood pressures using ambulatory blood pressure monitoring, with significantly fewer patients requiring treatment based on ambulatory blood pressure monitoring. Elevated ambulatory systolic blood pressure was consistently and significantly associated with increased risk for fatal and nonfatal stroke and cardiovascular events, independent of office blood pressure. For these reasons, the USPSTF recommends ambulatory blood pressure monitoring as the reference standard for confirming the diagnosis of hypertension. The USPSTF states that home blood pressure monitoring using appropriate protocols is an alternative method of confirmation if ambulatory blood pressure monitoring is not available.  

In a systematic review, Goyal and colleagues (2005) stated that "ambulatory blood pressure monitoring has established its use in the definition of white coat hypertension and monitoring of treatment of essential hypertension.  Any role for ambulatory blood pressure monitoring in heart failure is not well defined .... Prospective controlled studies on the impact of treatments on circadian blood pressure profile in congestive heart failure patients are needed".

1. mean 24-hour BP less than Task Force-defined 95th percentile,
2. mean 24-hour BP less than 95th percentile from pediatric normative ambulatory BP monitoring data, and
3. mean 24-hour BP less than ambulatory BP monitoring 95th percentile and BP load (percentage of BP readings during 24-hour period exceeding the 95th percentile) less than 25 %.

Clinic BP values were available in 67 otherwise healthy children who underwent ambulatory BP monitoring; 51 had confirmed clinic hypertension by Task Force criteria.  Frequency of WCH in these 51 patients with the stated criteria was 53 %, 45 %, and 22 %, respectively. Elevated BP load was found in 52 % (12/23) of patients with normal mean BP. The authors concluded that these findings suggested that many children referred for casual BP elevation have WCH even by strict diagnostic criteria.  Ambulatory BP monitoring may help differentiate WCH from persistent hypertension, thereby avoiding unnecessary diagnostic evaluation and identifying children most likely to benefit from early intervention.

Stergiou et al (2004) stated that office and out-of-office BP measurements are being used for the diagnosis of hypertension in children and adolescents.  The U.S. National Heart, Lung, and Blood Institute have recently presented a new classification of BP.  On the basis of office measurements the 90th, 95th and 99th percentile for gender, age and height are used to classify children and adolescents as normotensive, pre-hypertensive and stage-1 or stage-2 hypertensive.  Although auscultation using a standard mercury sphygmomanometer remains the recommended method, accumulating evidence suggests that ambulatory BP monitoring is useful for the detection of WCH and the prediction of target organ damage in children and adolescents.  Studies have shown ambulatory BP to be more reproducible than office measurements and normative tables for ambulatory measurements have been developed from cross-sectional studies in children and adolescents.  In regard to home measurements in children, there are limited data from small trials showing lower BP levels than daytime ambulatory BP.  The authors concluded that ambulatory BP monitoring is already finding a role as a supplementary source of information in children and adolescents, whereas at present home measurements should not be used for decision making in this population.

In a review and meta-analysis, Bliziotis et al (2012) examined the association of home BP measurements with target organ damage.  A PubMed and Cochrane Library search (1950 to 2011) revealed 23 studies reporting comparative data of home BP versus ambulatory and/or office measurements in terms of their association with several indices of target organ damage.  Correlation coefficients were pooled by random-effects model meta-analysis.  A total of 14 studies (n = 2,485) assessing echocardiographic left ventricular mass index (LVMI) showed similar correlations with home (coefficients r = 0.46/0.28, systolic/diastolic) as with ambulatory BP (0.37/0.26, p = NS for difference versus home BP), and superior to office measurements (r = 0.23/0.19, p < 0.001/0.009 for difference versus home BP).  Four methodologically heterogeneous studies assessing the glomerular filtration rate (n = 609) could not be pooled or lead to a concrete result.  Four studies assessing carotid intima-media thickness (n = 1,222), 3 assessing pulse wave velocity (n = 720) and 2 assessing urinary protein excretion (n = 156) showed no difference in pooled correlation coefficients with home versus office BP measurements.  With all the measurement methods, systolic blood pressure (SBP) was more closely associated with target organ damage than diastolic blood pressure (DBP).  The authors concluded that these data suggested that home BP is as good as ambulatory monitoring and superior to office measurements in regard to their association with pre-clinical organ damage assessed by echocardiographic LVMI.  They stated that more research is needed to evaluate the relationship of home BP with other indices of target organ damage.

Swartz et al (2008) determined the cost-effectiveness of ambulatory BP monitoring in the initial evaluation of stage 1 hypertension.  Retrospective chart review of data for children referred to Texas Children's Hospital hypertension clinic between January 2005 and August 2006 was performed.  These investigators compared the costs of standard evaluations versus the initial use of ambulatory BP monitoring for children with clinic BP measurements suggesting stage 1 hypertension.  Charges for clinic visits, laboratory tests, and imaging were obtained from the Texas Children's Hospital billing department.  A total of 267 children were referred – 139 children did not receive ambulatory BP monitoring; 54 met clinical indications for ambulatory BP monitoring but did not receive it because it was not a covered expense (44 children) or the family refused the study (10 children); 126 children received clinically indicated ambulatory BP monitoring, paid for either through insurance or by the family.  Fifty-eight children (46 %) had confirmed white-coat hypertension, 62 (49 %) stage 1 hypertension, and 6 (5 %) stage 2 hypertension.  With the observed prevalence of WCH, initial ambulatory BP monitoring use yielded net savings after evaluation of 3 patients, with projected savings of $2.4 million per 1,000 patients.  The authors concluded that ambulatory BP monitoring in the initial evaluation of suspected childhood hypertension is highly cost-effective.  Awareness of cost saving potential may increase the availability of ambulatory BP monitoring for evaluation of new-onset hypertension.

Muxfeldt et al (2012) stated that resistant hypertension is defined as uncontrolled office BP, despite the use of greater than or equal to 3 anti-hypertensive drugs.  Ambulatory BP monitoring (ABPM) is mandatory to diagnose 2 different groups, those with true and white-coat resistant hypertension.  Patients are found to change categories between controlled/uncontrolled ambulatory pressures without changing their office BP.  In this way, ABPM should be periodically repeated.  The aim of this study was to evaluate the most appropriate time interval to repeat ABPM to assure sustained BP control in patients with white-coat resistant hypertension.  This prospective study enrolled 198 patients (69 % women; mean age of 68.9 +/- 9.9 years) diagnosed as white-coat resistant hypertension on ABPM.  Patients were submitted to a second confirmatory examination 3 months later and repeated twice at 6-month intervals.  Statistical analyses included Bland-Altman repeatability coefficients and multi-variate logistic regression.  Mean office BP was 163 ± 20/84 ± 17 mm Hg, and mean 24-hour BP was 118 ± 8/66 ± 7 mm Hg.  White-coat resistant hypertension diagnosis presented a moderate reproducibility and was confirmed in 144 patients after 3 months.  In the 3rd and 4th ABPMs, 74 % and 79 % of patients sustained the diagnosis.  In multi-variate regression, a daytime systolic blood pressure less than or equal to 115 mm Hg in the confirmatory ABPM triplicated the chance of white-coat resistant hypertension status persistence after 1 year.  The authors concluded that a confirmatory ABPM is necessary after 3 months of the 1st white-coat-resistant hypertension diagnosis, and the procedure should be repeated at 6-month intervals, except in patients with daytime systolic blood pressure less than or equal to 115 mm Hg, in whom it may be repeated annually.

Vollebregt and colleagues (2013) stated that it is not known whether automated devices for measuring BP perform better than conventional sphygmomanometry in predicting preeclampsia.  In a prospective, observational, cohort study, these investigators compared 2 different automated devices with conventional sphygmomanometry for their association with development of preeclampsia or gestational hypertension.  A total of 289 healthy normotensive women of whom 235 were nulliparous and 44 parous with preeclampsia in a previous pregnancy were include in this study.  At 8 to 11 weeks of pregnancy, BP was measured with 2 different automated devices (continuous finger arterial pressure waveform registration and ABPM) and with conventional sphygmomanometry.  Main outcome measures were preeclampsia and gestational hypertension.  Blood pressure in the 1st trimester, as measured with all 3 methods, was significantly higher in women who developed preeclampsia or gestational hypertension.  After adjustment for previous preeclampsia, the point estimate of the odds ratios for association with later preeclampsia for both automated devices were comparable and higher than for conventional sphygmomanometry; however, differences were not statistically significant.  The odds ratio (95 % confidence intervals) for every 1 mmHg pressure increase of mean arterial pressure was 1.08 (1.02 to 1.15) for sphygmomanometry, 1.17 (1.09 to 1.27) for finger arterial pressure waveform registration, and 1.17 (1.07 to 1.27) for ABPM.  Results were comparable if preeclampsia and gestational hypertension were analyzed together.  The authors concluded that BP in the 1st trimester was associated with the development of hypertensive disorders of pregnancy; however, no significant differences were found between measurements by automatic devices including ABPM compared with conventional sphygmomanometry.

O’Brien and Dolan (2016) reviewed the current recommendations for ABPM and the use of ABPM in assessing treatment.  These investigators reviewed current international guidelines and undertook a critical review of evidence supporting the clinical use of ABPM in effectively managing anti-hypertensive drug treatment.  Current guidelines emphasize the diagnostic superiority of ABPM, mainly from the ability of the technique to identify sustained hypertension by allowing for the exclusion of white-coat hypertension and by demonstrating the presence of masked hypertension; ABPM also offers diagnostic insights into nocturnal patterns of BP, such as dipping and non-dipping, reverse dipping, and excessive dipping, and the presence of nocturnal hypertension; although less attention is given to the nocturnal behavior of BP in clinical practice, the nocturnal patterns of BP have particular relevance in assessing the response to BP-lowering medication.  Surprisingly, although the current guidelines give detailed recommendations on the diagnostic potential and use of ABPM, there are scant recommendations on the benefits and application of the technique for the initiation of BP-lowering therapy in clinical practice and virtually no recommendations on how it might be used to assess the effectiveness of drug treatment.  The authors concluded that i view of a deficiency in the literature on the role of ABPM in assess the effectiveness of drug treatment, they put forward proposals to correct this deficiency and guide the prescribing physician on the most appropriate drug administration and dosage over time.

Routine Use Before Initiation of Continuous Positive Airway Pressure (CPAP) Therapy

Castro-Grattoni and colleagues (2017) stated that the reduction in BP with continuous positive airway pressure (CPAP) is modest and highly variable.  These researchers identified the variables that predict BP response to CPAP; 24-hour ABPM, C-reactive protein (CRP), leptin, adiponectin and 24-hour urinary catecholamine were measured before and after 6 months of CPAP in obstructive sleep apnea (OSA) patients.  A total of 88 middle-aged, obese male patients with severe OSA (median apnea-hypopnea index [AHI] of 42 events/hour) were included; 28.4 % had hypertension; 62 patients finished the study, and 60 were analyzed.  The daytime DBP (-2 mmHg) and norepinephrine (-109.5 nmol/day) were reduced after CPAP, but no changes in the 24-hour BP, night-time BP, dopamine, epinephrine, CRP, leptin or adiponectin were detected.  The nocturnal normotension was associated with an increased night-time-BP (+4 mmHg) after CPAP, whereas nocturnal hypertension was associated with a reduction of 24-hour BP (-3 mmHg).  A multi-variate linear regression model showed differential night-time BP changes after CPAP.  Specifically, low night-time heart rate (HR; less than 68 bpm) and BP dipper profile were associated with increased night-time BP and new diagnosis of nocturnal hypertension.  The authors concluded that these findings suggested that nocturnal hypertension, circadian BP pattern and night-time HR could be clinical predictors of BP response to CPAP and support the usefulness of 24-hour ABPM for OSA patients before treatment initiation.  Moreover, they stated that these findings need to be confirmed in further studies.

Accuracy of Automated BP Measurements in Patients with Atrial Fibrillation

Clark and colleagues (2019) noted that atrial fibrillation (AF) affects approximately 3 % of the general population and is twice as common with hypertension. Validation protocols for automated sphygmomanometers exclude people with AF, raising concerns over accuracy of hypertension diagnosis or management, using out-of-office BP monitoring, in the presence of AF.  Some devices include algorithms to detect AF; a feature open to misinterpretation as offering accurate BP measurement with AF.  These researchers examined the accuracy of automated devices, with or without AF detection, for measuring BP.  They searched Medline and Embase to October 2018 for studies comparing automated BP measurement devices to a standard mercury sphygmomanometer contemporaneously.  Data were extracted by 2 reviewers.  Mean BP differences between devices and mercury were calculated, where not reported and compared; meta-analyses were undertaken where possible.  These investigators included 13 studies reporting 14 devices.  Mean systolic and diastolic BP differences from mercury ranged from -3.1 to + 6.1/-4.6 to +9.0 mmHg.  Considerable heterogeneity existed between devices (I2: 80 to 90 %).  Devices with AF detection algorithms appeared no more accurate for BP measurement with AF than other devices.  A previous review concluded that oscillometric devices were accurate for systolic but not diastolic BP measurement in AF.  The findings of this study did not support that conclusion.  As a consequence of heterogeneity between devices, they should be evaluated on individual performance.  The authors found no evidence that devices with AF detection measured BP more accurately in AF than other devices.  These researchers stated that more home or ambulatory automated BP monitors require validation in populations with AF.

Appendix

Blood Pressure Levels by Age and Height Percentile: Blood Pressure Levels for Boys and Girls by Age and Height Percentile

The above policy is based on the following references: