Intravascular ultrasound lumen area parameters for assessment of physiological ischemia by fractional flow reserve in intermediate coronary artery stenosis.

BACKGROUND: A fractional flow reserve (FFR) of <0.8 is currently used to guide revascularization in lesions with intermediate coronary stenosis. Whether there is an intravascular ultrasound (IVUS) measurement or a cutoff value that can reliably determine which of these intermediate lesions requires intervention is unclear. AIMS: We assessed IVUS measurement accuracy in defining functional ischemia by FFR. METHODS: The analysis included 205 intermediate lesions (185 patients) located in vessel diameters >2.5 mm. Positive FFR was considered present at <0.8. IVUS measurements were correlated to the FFR findings in intermediate lesions with 40%-70% stenosis. Fifty-four (26.3%) lesions had FFR<0.8. RESULTS: There was moderate correlation between FFR and IVUS measurements, including minimum lumen area (MLA) (r=0.36, P<.001), minimum lumen diameter (MLD) (r=0.25, P=<.001), lesion length (r=-0.43, P<.001), and area stenosis (r=-0.33, P=.01). A receiver operating characteristic curve (ROC) identified MLA<3.09 mm(2) (sensitivity 69.2%, specificity 79.5%) as the best threshold value for FFR<0.8. The correlation between FFR and IVUS was better for large vessels compared to small vessels. ROC analysis identified the best threshold value for FFR<0.8 of MLA<2.4 mm(2) [area under curve (AUC)=0.74] in lesions with reference vessel diameters of 2.5-3 mm, MLA<2.7 mm(2) (AUC=0.77) in lesions with reference vessel diameters of 3-3.5 mm, and MLA<3.6 mm(2) (AUC=0.70) in lesions with reference vessel diameters >3.5 mm. CONCLUSION: Anatomic measurements of intermediate coronary lesions obtained by IVUS show a moderate correlation to FFR values. The correlation was better for larger-diameter vessels. Vessel size should always be taken into account when determining the MLA associated with functional ischemia.

A novel, minimally invasive access technique versus standard 18-gauge needle set for femoral access.

OBJECTIVE: To compare access site complications with the Micropuncture 21 gauge (G) needle set to the standard 18G needle in patients undergoing percutaneous coronary intervention (PCI) using the femoral approach. BACKGROUND: Vascular access site complications are the most common problems after PCI. The Micropuncture 21G needle set was recently introduced to minimize such complications. METHODS: A cohort of 3,243 consecutive patients was studied. Patients receiving thrombolytics, IIb/IIIa antagonist, coumadin, or intra-aortic balloon pump were excluded. Micropuncture access was used in 544 patients and standard 18G needle in 2,699. All access sites were managed with a vascular closure device. Primary endpoints included vascular perforation or limb ischemia requiring repair, retroperitoneal bleeding, pseudoaneurysm, arteriovenous fistula, and groin hematoma (>4 cm). RESULTS: Patients undergoing PCI with Micropuncture were at higher risk: they were older (65.9 ± 9 vs. 64.7 ± 11.8, P = 0.03); had lower body surface area (1.9 ± 0.2 vs. 2.0 ± 0.3, P = 0.02); more prevalent peripheral vascular disease [119 (21.9%) vs. 380 (14.1%), P < 0.001] and renal failure [106 (19.6%) vs. 318 (11.8%), P < 0.001]. Overall, there was no significant difference in the access site complications rate using Micropuncture vs. standard needle, 7 (1.3%) vs. 27 (1.0%), respectively, P = 0.54. The Micropuncture group had significantly higher retroperitoneal bleeding, 0.7% vs. 0.18%, P = 0.04. After multivariable adjustment, only age remained significantly associated with vascular complications (OR 1.03, P = 0.04). CONCLUSIONS: Femoral access using the Micropuncture technique did not reduce the incidence of vascular complications and the marginally higher than expected retroperitoneal bleeding is based on very small numbers. The routine use of the Micropuncture set and its technique should be revisited.

Effect of insurance type on adverse cardiac events after percutaneous coronary intervention.

Previous studies have documented disparities in both access to invasive cardiovascular procedures and outcomes in patients with Medicaid, Medicare, or no insurance. Outcomes by insurance have yet not been examined in a percutaneous coronary intervention (PCI) population. Data from patients undergoing PCI from June 2000 to June 2009 were retrospectively analyzed. Insurance was categorized as private, Medicare, Medicaid, and uninsured, according to the primary insurance at discharge. The outcome variable of interest was major adverse cardiac events (a composite of death, Q-wave myocardial infarction, and target vessel revascularization) at 1 year. Multivariable Cox regression analysis was stratified according to age <65 and ≥65 years. Of the 13,573 patients who had undergone PCI, 6,653 (49.0%) had private insurance, 6,150 (45.3%) had Medicare, 486 (3.6%) had Medicaid, and 284 (2.1%) were uninsured. Of the patients <65 years old, Medicaid (hazard ratio [HR] 1.59, 95% confidence interval [CI] 1.04 to 2.43), Medicare (HR 2.18, 95% CI 1.58 to 2.99), and no insurance (HR 2.41, 95% CI 1.36 to 4.27) were associated with greater rates of adjusted major adverse cardiac events at 1 year compared with private insurance. Of the patients ≥65 years old, only Medicaid (HR 3.07, 95% CI 1.09 to 8.61) was associated with a greater rate of adjusted major adverse cardiac events at 1 year. In conclusion, patients with government-sponsored insurance and no insurance have worse cardiovascular outcomes than patients with private insurance after PCI at 1 year. This implies that the provision of health insurance alone might not have a dramatic effect on cardiovascular outcomes after PCI.

Insurance type influences the use of drug-eluting stents.

OBJECTIVES: We sought to examine the effect of insurance type upon the likelihood of receiving a drug-eluting stent (DES). BACKGROUND: Recent guidelines suggest that consideration of a patient's resources should play a role in decisions to use DES. Previous studies have also documented disparities in both access to care and cardiovascular outcomes according to race, insurance, and socioeconomic status. The effect of insurance status upon the decision to use DES is unclear. METHODS: Patients undergoing percutaneous coronary intervention (PCI) with stenting from April 2003 to June 2009, the so-called DES era, were retrospectively analyzed. Multivariable logistic regression was performed separately for patients <65 years and patients > or =65 years, with receipt of > or =1 DES during PCI as the outcome variable of interest. Insurance type was categorized as private, Medicare, Medicaid, and uninsured, based upon the primary insurance at discharge. Data regarding duration of clopidogrel therapy at 1 month, 6 months, and 1 year was also collected. RESULTS: Among the 12,584 patients who underwent PCI with stenting, 6,157 (48.9%) had private insurance, 5,689 (45.2%) had Medicare, 467 (3.7%) had Medicaid, and 271 (2.2%) were uninsured at the time of hospital discharge. There were no significant differences by insurance type in duration of dual antiplatelet therapy at 1 year. Both multivariable logistic regressions showed that Medicaid patients (odds ratio [OR]: 0.60; 95% confidence interval [CI]: 0.46 to 0.78 for age <65 years; OR: 0.45; 95% CI: 0.24 to 0.85 for age > or =65 years) and patients without insurance (OR: 0.57; 95% CI: 0.42 to 0.78 for age <65 years; OR: 0.20; 95% CI: 0.05 to 0.86 for age > or =65 years) were less likely to receive DES. CONCLUSIONS: Insurance status has a significant impact upon the decision to use DES. Efforts to address this disparity should focus on the patient-provider level.

Application of regression-discontinuity analysis in pharmaceutical health services research.

OBJECTIVE: To demonstrate how a relatively underused design, regression-discontinuity (RD), can provide robust estimates of intervention effects when stronger designs are impossible to implement. DATA SOURCES/STUDY SETTING: Administrative claims from a Mid-Atlantic state Medicaid program were used to evaluate the effectiveness of an educational drug utilization review intervention. STUDY DESIGN: Quasi-experimental design. DATA COLLECTION/EXTRACTION METHODS: A drug utilization review study was conducted to evaluate a letter intervention to physicians treating Medicaid children with potentially excessive use of short-acting beta(2)-agonist inhalers (SAB). The outcome measure is change in seasonally-adjusted SAB use 5 months pre- and postintervention. To determine if the intervention reduced monthly SAB utilization, results from an RD analysis are compared to findings from a pretest-posttest design using repeated-measure ANOVA. PRINCIPAL FINDINGS: Both analyses indicated that the intervention significantly reduced SAB use among the high users. Average monthly SAB use declined by 0.9 canisters per month (p<.001) according to the repeated-measure ANOVA and by 0.2 canisters per month (p<.001) from RD analysis. CONCLUSIONS: Regression-discontinuity design is a useful quasi-experimental methodology that has significant advantages in internal validity compared to other pre-post designs when assessing interventions in which subjects' assignment is based on cutoff scores for a critical variable.

Osteoporosis management in a Medicaid population after the Women's Health Initiative study.

OBJECTIVE: Publication of the Women's Health Initiative (WHI) study has changed our understanding on the effects of hormone replacement therapy. This study was designed to evaluate patterns of antiosteoporosis medication (AOM) use in a Medicaid population before and after the release of the WHI study results. METHODS: A descriptive time series analysis was conducted among women 50 years of age and older who were enrolled in the Pennsylvania Medicaid program from December 1, 2001, through December 31, 2002. All AOMs were identified, including estrogens, bisphosphonates, selective estrogen receptor modulators (SERMs), and calcitonin. The monthly prevalence of each AOM and drug class was estimated. Comparisons between pre-WHI (December 1, 2001-July 30, 2002) and post-WHI (August 1, 2002-December 31, 2002) study periods were made for overall AOM use by AOM drug class as well as by recipient characteristics. RESULTS: The overall prevalence of AOM did not change between pre-WHI and post-WHI study publication. However, there were significant changes in the prevalence of certain AOM drug classes. Estrogen use decreased significantly after the WHI study release for all age and racial groups. The prevalence for bisphosphonates and SERM increased significantly in the post-WHI period. CONCLUSIONS: The WHI study influenced patterns of use of all types of AOM, decreasing estrogen and increasing nonestrogen use among postmenopausal women in a Medicaid program. These results suggest that the WHI study affected patterns of use of bone protective pharmacotherapy, with a shift in bone protection therapy use from estrogen to nonestrogen AOMs.