Adverse cardiac remodeling is absent in patients with true controlled resistant hypertension.

Resistant hypertension (RHTN), defined as blood pressure (BP) that is uncontrolled with ≥3 medications, including a long-acting thiazide diuretic, also includes a subset with BP that is controlled with ≥4 medications, so-called controlled RHTN. This resistance is attributed to intravascular volume excess. Patients with RHTN overall have a higher prevalence of left ventricular hypertrophy (LVH) and diastolic dysfunction compared to patients with non-RHTN. We tested the hypothesis that patients with controlled RHTN due to the intravascular volume excess have higher left ventricular mass index (LVMI), higher prevalence of LVH, larger intracardiac volumes, and more diastolic dysfunction compared to patients with controlled non-resistant hypertension (CHTN), defined as BP controlled with ≤3 anti-hypertensive medications. Patients with controlled RHTN (n = 69) or CHTN (n = 63) who were treated at the University of Alabama at Birmingham were offered enrollment and underwent cardiac magnetic resonance imaging. Diastolic function was assessed by peak filling rate, time needed in diastole to recover 80% of stroke volume, E:A ratios and left atrial volume. LVMI was higher in patients with controlled RHTN (64.4 ± 22.5 vs 56.9 ± 11.5; P = .017). Intracardiac volumes were similar in both groups. Diastolic function parameters were not significantly different between groups. There were no significant differences in age, gender, race, body mass index, dyslipidemia between the two groups. The findings show that patients with controlled RHTN have higher LVMI, but comparable diastolic function to those of patients with CHTN.

Incidence and predictors of MRI scan utilization in MRI-conditional pacemaker recipients: A multicenter experience.

BACKGROUND: Patient characteristics, higher device cost, and vendor contracts likely prevent use of magnetic resonance imaging (MRI)-conditional pacemakers (MRC) in all pacemaker (PM)-eligible patients. We sought to identify the incidence and predictors of MRI scan utilization in MRC recipients. METHODS: Patients receiving an MRC or non-MRI-conditional PM (NMRC) at four centers were included. Incidence of MRI scans following PM insertion was obtained from hospital records and patient phone calls. RESULTS: Of 1,244 patients (74 ± 12 years, 54.6% male), 927 had MRC and 317 had NMRC. At baseline, MRC recipients had a higher incidence of atrial tachycardia and MRI risk factors (syncope, recurrent falls, neurological disease, severe musculoskeletal disease, malignancy). In the MRC group, more patients had commercial health insurance (26% vs 15%, P < 0.001). Sixty MRC patients (6.5%) had an MRI during 21 ± 17 months' follow-up. Using the Weilbull parametric survival model, the projected percentage of MRC patients receiving an MRI scan at 7- and 11-year follow-up were 45% and 73%, respectively. By multivariate regression, a prior history of MRI (odds ratio [OR] 4.5, 95% confidence interval [CI] 2.2-9.1, P < 0.001) and active smoking (OR 2.65, 95% CI 1.1-6.7, P  =  0.039) independently predicted the performance of an MRI following MRC implant. CONCLUSIONS: In this MRC cohort, MRI scan utilization during follow-up was low but projection analyses showed a higher incidence over the lifetime of the MRC. A history of prior MRI and active smoking independently predicted the performance of an MRI scan during follow-up.

Refractory Hypertension Is not Attributable to Intravascular Fluid Retention as Determined by Intracardiac Volumes.

Refractory hypertension (RfHTN) is an extreme phenotype of antihypertensive treatment failure defined as lack of blood pressure control with ≥5 medications, including a long-acting thiazide and a mineralocorticoid receptor antagonist. RfHTN is a subgroup of resistant hypertension (RHTN), which is defined as blood pressure >135/85 mm Hg with ≥3 antihypertensive medications, including a diuretic. RHTN is generally attributed to persistent intravascular fluid retention. It is unknown whether alternative mechanisms are operative in RfHTN. Our objective was to determine whether RfHTN is characterized by persistent fluid retention, indexed by greater intracardiac volumes determined by cardiac magnetic resonance when compared with controlled RHTN patients. Consecutive patients evaluated in our institution with RfHTN and controlled RHTN were prospectively enrolled. Exclusion criteria included advanced chronic kidney disease and masked or white coat hypertension. All enrolled patients underwent biochemical testing and cardiac magnetic resonance. The RfHTN group (n=24) was younger (mean age, 51.7±8.9 versus 60.6±11.5 years; P=0.003) and had a greater proportion of women (75.0% versus 43%; P=0.02) compared with the controlled RHTN group (n=30). RfHTN patients had a greater left ventricular mass index (88.3±35.0 versus 54.6±12.5 g/m2; P<0.001), posterior wall thickness (10.1±3.1 versus 7.7±1.5 mm; P=0.001), and septal wall thickness (14.5±3.8 versus 10.0±2.2 mm; P<0.001). There was no difference in B-type natriuretic peptide levels and left atrial or ventricular volumes. Diastolic dysfunction was noted in RfHTN. Our findings demonstrate greater left ventricular hypertrophy without chamber enlargement in RfHTN, suggesting that antihypertensive treatment failure is not attributable to intravascular volume retention.

Cost-effectiveness analysis of magnetic resonance imaging-conditional pacemaker implantation: Insights from a multicenter study and implications in the current era.

BACKGROUND: Magnetic resonance imaging (MRI)-conditional pacemakers (M-PPMs) grant patients greater accessibility to MRI scans. The cost-effectiveness of implanting M-PPM is unknown. OBJECTIVE: The purpose of this study was to determine the cost-effectiveness of M-PPM implantation. METHODS: Cost-effectiveness analysis was performed on patients receiving a M-PPM across 4 institutions. The incremental cost-effectiveness ratio (ICER) was calculated by dividing the sum of the total incremental cost of implanting a M-PPM vs a conventional pacemaker and the cost of MRI scans by the utility of MRI scans in terms of quality-adjusted life-years (QALY) gained. QALY and lifespan of M-PPM (7-11 years) data were obtained from the literature. The benchmark of <$100,000 per QALY was used as the threshold for cost-effectiveness. Computer modeling/simulations were used to calculate the percentage of patients required to achieve this benchmark, to extrapolate the cumulative projected percentage of patients utilizing MRI scans over the lifespan of a M-PPM via the Weibull parametric survival model, and to conduct univariate and multivariate, probabilistic sensitivity analyses. RESULTS: The ICER during the follow-up period (21 ± 17 months) was $451,569. The cost-effectiveness ICER benchmark is reached 7.0 years postimplantation, when a projected 38% of recipients would receive MRI scans. The projected percentage of patients receiving MRI scans at 11 years was 58%, yielding an ICER of $74,221 per QALY. Henceforth, assuming increased MRI usage in regular PPM based on Centers for Medicare & Medicaid Services memo CAG00399R4 and decreased cost of M-PPM, M-PPM implantation is still cost-effective, with a lifetime ICER of $49,817 per QALY. CONCLUSION: M-PPM implantation is cost-effective over the lifespan of a M-PPM based on projected usage of MRI.