The role of magnetic resonance angiography in peripheral artery disease.

Magnetic resonance angiography is an important diagnostic modality in the evaluation of peripheral artery disease. It has gained popularity within the last two decades. It is accurate, non-invasive, and avoids exposure to ionizing radiation. We are reviewing the clinical applications technique and safety issues related to this valuable tool.

The use of cardiac-CT alone to exclude left atrial thrombus before atrial fibrillation ablation: Efficiency, safety, and cost analysis.

BACKGROUND: Atrial fibrillation (AF) is a growing financial burden on the healthcare system. Cardiac computed tomographic angiography (CCTA) is needed for pulmonary vein mapping before AF ablation (AFA). CCTA has shown to be an alternative to transesophageal echocardiogram (TEE) to rule out left atrial appendage thrombus (LAAT) pre-AFA. We aim to examine the safety, cost-effectiveness, and time-efficiency of utilizing CCTA alone to rule out LAAT before AFA. METHODS: We prospectively screened patients with paroxysmal AF undergoing cryoablation. CCTA with delayed enhancement was performed within 72 hours of AFA. Once LAAT was ruled out, patients were enrolled and planned TEE was cancelled. A retrospective control cohort that had both CCTA and TEE prior to AFA was identified. Direct cost data, electrophysiology laboratory utilization time, and 30-day stroke outcomes were collected from the EMR, follow-up phone calls, or clinic visits, and comparative analyses were performed. RESULTS: Seventy patients met the inclusion criteria in the prospective CCTA-only cohort, and 71 for the retrospective CCTA+TEE cohort. Baseline characteristics were similar between the two groups. There was a nonsignificant reduction in overall cost ($15,870 ± 1,710 vs $16,557 ± 2,508, P = 0.06) in CCTA-only cohort, whereas the electrophysiology laboratory utilization time was significantly reduced (241.6 ± 41.7 vs 181.3 ±36.4 minutes, P < 0.001). There were no strokes reported on 30-day follow-up in the CCTA-only group. CONCLUSIONS: In low-to-intermediate stroke risk patients with paroxysmal AF undergoing cryoablation, eliminating TEE and employing CCTA-only strategy to rule-out LAAT improves electrophysiology laboratory efficiency without influencing periprocedural cost or increasing postprocedural stroke risk.

Pulmonary Arterial Enlargement is Associated With Acute Chest Pain in Patients Without Obstructive Coronary Artery Disease.

BACKGROUND: Pulmonary hypertension (PH) is an underdiagnosed cause for chest pain in patients without significant coronary artery disease (CAD). Studies showed that enlarged pulmonary arterial (PA) and right ventricular chamber sizes correlate with the severity of PH. Therefore, we studied the association between chest pain, right ventricular dimensions (RVDs), and PA size on coronary coronary tomographic angiography (CCTA). METHODS: The CCTA of 87 patients presenting with chest pain without evidence of obstructive CAD was examined. The PA diameter (PAD), right atrial dimension (RAD), and RVD were measured. A comparative control cohort included 31 patients who presented without cardiopulmonary complaints and underwent thoracic CT. The risk for obstructive sleep apnea (OSA) was assessed using STOP-BANG questionnaires. RESULTS: Patients with chest pain without obstructive CAD showed markedly dilated right atrial and ventricular chambers compared with standard parameters (right atrium: 48 ± 6.4 mm; right ventricle long axis: 61 ± 9.5 mm). When comparing chest pain vs non-chest pain group, respectively, the mean PAD measured 25.92 ± 0.43 mm vs 22.89 ± 0.38 mm (P < .001), RAD2 measured 40.1423 ± 0.7108 mm vs 34.8800 ± 1.0245 mm (P = .0048), and RVD2 measured 31.7729 ± 0.7299 mm vs 27.6379 ± 1.6178 mm (P = .034). Chest pain was associated with higher PAD (odds ratio [OR]: 11.11, P < .05) after adjusting for age, sex, body mass index, history of hypertension, hyperlipidemia, congestive heart failure, chronic obstructive pulmonary disease, OSA, and smoking. The chest pain group had a mean STOP-BANG score of 3.9 ± 1.8 in all patients, and 3.62 ± 0.20 in patients without known history of OSA, representing an elevated risk index for the disease. CONCLUSIONS: In patients presenting with chest pain without obstructive CAD on CCTA, there is a strong association between the presence of chest pain and enlarged PAD. They also represent a high-risk group for OSA.

Is 30-Day Mortality after Admission for Heart Failure an Appropriate Metric for Quality?

BACKGROUND: The Centers for Medicare and Medicaid Services (CMS) model for publicly reporting national 30-day-risk-adjusted mortality rates for patients admitted with heart failure fails to include clinical variables known to impact total mortality or take into consideration the culture of end-of-life care. We sought to determine if those variables were related to the 30-day mortality of heart failure patients at Geisinger Medical Center. METHODS: Electronic records were searched for patients with a diagnosis of heart failure who died from any cause during hospitalization or within 30 days of admission. RESULTS: There were 646 heart-failure-related admissions among 530 patients (1.2 admissions/patient). Sixty-seven of the 530 (13%) patients died: 35 (52%) died during their hospitalization and 32 (48%) died after discharge but within 30 days of admission; of these, 27 (40%) had been transferred in for higher-acuity care. Fifty-one (76%) died from heart failure, and 16 (24%) from other causes. Fifty-five (82%) patients were classified as American Heart Association Stage D, 58 (87%) as New York Heart Association Class IV, and 30 (45%) had right-ventricular systolic dysfunction. None of the 32 patients who died after discharge met recommendations for beta-blockers. Criteria for prescribing angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and mineralocorticoid receptor blockers were not met by 33 of the 34 patients (97%) with heart failure with reduced ejection fraction not on one of those drugs. Fifty-seven patients (85%) had a do-not-resuscitate (DNR) status. CONCLUSION: A majority of heart failure-related mortality was among patients who opted for a DNR status with end-stage heart failure, limiting the appropriateness of administering evidence-based therapies. No care gaps were identified that contributed to mortality at our institution. The CMS 30-day model fails to take important variables into consideration.

Design Optimization for Accurate Flow Simulations in 3D Printed Vascular Phantoms Derived from Computed Tomography Angiography.

3D printing has been used to create complex arterial phantoms to advance device testing and physiological condition evaluation. Stereolithographic (STL) files of patient-specific cardiovascular anatomy are acquired to build cardiac vasculature through advanced mesh-manipulation techniques. Management of distal branches in the arterial tree is important to make such phantoms practicable. We investigated methods to manage the distal arterial flow resistance and pressure thus creating physiologically and geometrically accurate phantoms that can be used for simulations of image-guided interventional procedures with new devices. Patient specific CT data were imported into a Vital Imaging workstation, segmented, and exported as STL files. Using a mesh-manipulation program (Meshmixer) we created flow models of the coronary tree. Distal arteries were connected to a compliance chamber. The phantom was then printed using a Stratasys Connex3 multimaterial printer: the vessel in TangoPlus and the fluid flow simulation chamber in Vero. The model was connected to a programmable pump and pressure sensors measured flow characteristics through the phantoms. Physiological flow simulations for patient-specific vasculature were done for six cardiac models (three different vasculatures comparing two new designs). For the coronary phantom we obtained physiologically relevant waves which oscillated between 80 and 120 mmHg and a flow rate of ~125 ml/min, within the literature reported values. The pressure wave was similar with those acquired in human patients. Thus we demonstrated that 3D printed phantoms can be used not only to reproduce the correct patient anatomy for device testing in image-guided interventions, but also for physiological simulations. This has great potential to advance treatment assessment and diagnosis.

Temporal Trends, Complications, and Predictors of Outcomes Among Nonagenarians Undergoing Percutaneous Coronary Intervention: Insights From the Veterans Affairs Clinical Assessment, Reporting, and Tracking Program.

OBJECTIVES: The aim of this study was to determine temporal trends, in-laboratory complications, mortality, and predictors of mortality among nonagenarians undergoing percutaneous coronary intervention (PCI). BACKGROUND: Nonagenarians (patients 90 years of age or older) undergoing PCI are often underrepresented in clinical trials, and their management remains challenging and controversial. METHODS: All veterans undergoing PCI with data recorded in the Veterans Affairs Clinical Assessment, Reporting, and Tracking program from 2005 to 2014 were evaluated. Temporal trends in the use of PCI, occurrence of in-laboratory complications, and 30-day and 1-year mortality were assessed. Using a frailty model, predictors of 30-day and 1-year mortality in nonagenarians were evaluated. RESULTS: Among all veterans undergoing PCI (n = 67,148) between 2005 and 2014, 274 (0.4%) were nonagenarians. The proportion of nonagenarians increased from 0.25% in 2008 to 0.58% in 2014. Compared with younger patients, nonagenarians had a greater risk for acute cardiogenic shock post-procedure (0.73% vs. 0.12%; p = 0.04) and no reflow (2.9% vs. 1.0%; p = 0.02). Unadjusted (10.6% vs. 1.4%; p < 0.0001) and adjusted 30-day mortality (odds ratio: 2.14; 95% confidence interval [CI]: 1.42 to 3.22) and unadjusted (16.3% vs. 4.2%; p < 0.0001) and adjusted 1-year mortality (odds ratio: 1.82; 95% CI: 1.27 to 2.62) were higher among PCI patients who were nonagenarians. The National Cardiovascular Data Registry risk score was highly predictive of both 30-day (hazard ratio: 2.29; 95% CI: 1.86 to 2.82) and 1-year (hazard ratio: 1.43; 95% CI: 1.07 to 1.90) mortality among nonagenarians. CONCLUSIONS: Nonagenarians were a small but growing population with worse 30-day and 1-year mortality. The National Cardiovascular Data Registry risk score was a strong predictor of mortality in these patients.

Initial Simulated FFR Investigation Using Flow Measurements in Patient-specific 3D Printed Coronary Phantoms.

PURPOSE: Accurate patient-specific phantoms for device testing or endovascular treatment planning can be 3D printed. We expand the applicability of this approach for cardiovascular disease, in particular, for CT-geometry derived benchtop measurements of Fractional Flow Reserve, the reference standard for determination of significant individual coronary artery atherosclerotic lesions. MATERIALS AND METHODS: Coronary CT Angiography (CTA) images during a single heartbeat were acquired with a 320×0.5mm detector row scanner (Toshiba Aquilion ONE). These coronary CTA images were used to create 4 patient-specific cardiovascular models with various grades of stenosis: severe, <75% (n=1); moderate, 50-70% (n=1); and mild, <50% (n=2). DICOM volumetric images were segmented using a 3D workstation (Vitrea, Vital Images); the output was used to generate STL files (using AutoDesk Meshmixer), and further processed to create 3D printable geometries for flow experiments. Multi-material printed models (Stratasys Connex3) were connected to a programmable pulsatile pump, and the pressure was measured proximal and distal to the stenosis using pressure transducers. Compliance chambers were used before and after the model to modulate the pressure wave. A flow sensor was used to ensure flow rates within physiological reported values. RESULTS: 3D model based FFR measurements correlated well with stenosis severity. FFR measurements for each stenosis grade were: 0.8 severe, 0.7 moderate and 0.88 mild. CONCLUSIONS: 3D printed models of patient-specific coronary arteries allows for accurate benchtop diagnosis of FFR. This approach can be used as a future diagnostic tool or for testing CT image-based FFR methods.

Limited Fibrosis Progression but Significant Mortality in Patients Ineligible for Interferon-Based Hepatitis C Therapy.

BACKGROUND: Individuals ineligible for interferon-based hepatitis C therapy may have a worse prognosis than patients who have failed or not received treatment. AIMS: To provide information about the limitations of medical treatment of hepatitis C in real-world patients. METHODS: We studied 969 treatment-ineligible patients and 403 treated patients enrolled between 1/1/01 and 6/30/06; data were collected until 3/31/13. Treatment barriers were grouped into five categories and classified as health-related or health-unrelated. Fibrosis stage was assessed initially and at the end of follow-up. Mortality was determined by search of the Social Security database. Death certificates of treatment-ineligible patients were reviewed. RESULTS: Initially, 288 individuals had advanced fibrosis and compensated disease; 87 untreated patients developed advanced fibrosis during follow-up. Health-related treatment barriers were more commonly associated with fibrosis progression and worse survival. During follow-up, 247 untreated patients died: 47% of liver-related and 53% of liver-unrelated causes. Patients with significant comorbid illness had the worst five- (70%) and ten-year (50.5%) survival. Despite high mortality (47%) in persons with decompensated liver disease, no treatment barrier was associated with a greater incidence of liver-related death. Only significant comorbid medical illness was an independent predictor of disease progression; however, it was not associated with a greater incidence of liver-related death. Furthermore, treated patients had better 10-year survival than untreated patients on Kaplan-Meier analysis (80.3% vs. 74.5%, P = 0.005). CONCLUSION: Many patients with hepatitis C will die of non-liver-related causes and may not be helped by anti-viral treatment.