Faculty Bibliography

Background: Observation of the kinetics of tissue enhancement after the injection of a bolus of tracer has been used for the analysis of perfusion and related variables. In general, a gradient of concentration in the exchanging vascular compartment between the arterial and venous ends is represented in models via focus on maintaining the detailed balance between the advective and diffusive exchange processes. Conventionally, this is by considering the exchange in an Eulerian framework, based on considering the exchange within each compartment as a separate unit (e.g., tissue homogeneity (TH) model [1]). Herein, we present a Lagrangian approach to the exchange modeling, such that the blood flowing between compartments is considered as the primary unit, and, thereby, allowing for coarser discretization and more efficient calculations (Figure 1a). Methods: Eight patients (age 63 + 12 years) underwent first-pass perfusion (FPP) rest and regadenoson stress cardiac MRI (CMR) (3T scanner, Tim Trio, Siemens), followed by invasive coronary angiography. Images were obtained at 4 slice locations (the aortic root for the arterial input function (AIF) and 3 short-axis slices of the left ventricle for the wall) using a TurboFLASH readout with centric k-space reordering [2]. A proton density-weighted image was acquired for normalization [3]. Myocardial blood flow (MBF) (mL/g/min) and perfusion reserve index (MPRI) were calculated in endocardial and epicardial areas (total 32 segments) using our method by an expert in the field of MRI blinded to coronary angiography results. Results: The results of a representative patient (66 year old man) with history of hypertension, hyperlipidemia, Diabetes Mellitus and known coronary artery disease with prior stents on maximal medical therapy are shown in Figure 1b-f. Coronary angiography was performed via the right femoral artery and demonstrated severe triple-vessel disease with left to right collaterals (Figure 1b). First-pass CMR perfusion imaging demonstrates a delay!

OBJECTIVES: To describe predictors of the number of MitraClip devices implanted during percutaneous repair of mitral regurgitation (MR), and the long-term reduction in MR. BACKGROUND: In the EVEREST trials, one or two MitraClip devices were implanted to reduce MR, as needed. METHODS: Preprocedural transthoracic echocardiograms (TTE) and transesophageal echocardiograms (TEE) of 233 subjects who received 1 or 2 MitraClip devices in the EVEREST II Randomized Trial and High-Risk Study were analyzed. TEEs were reviewed for etiology of MR and pathoanatomic features of the valve, valve apparatus, and the regurgitant jet. Follow-up MR was assessed by TTE postprocedure and at 12 months. RESULTS: Ninety-seven subjects (42%) had two MitraClip devices implanted. Subjects with quantitatively more severe MR were more likely to receive two devices [mean regurgitant volume (RV) 45.9 +/- 21.9 vs. 36.3 +/- 18.5 mL, P <0.001]. On multivariate analysis, increased anterior leaflet thickness (OR 1.7 per mm, P = 0.007) and greater baseline RV (OR 1.21 per 10 mL, P = 0.01) were associated with increased odds of implanting two devices. The frequency of 2+ MR or less at discharge was similar regardless of the number of devices implanted. After propensity matching, patients had quantitatively similar MR at twelve-month follow-up, regardless of whether one or two MitraClip devices were implanted (P = 0.6). CONCLUSIONS: Subjects with thicker anterior mitral leaflets and more severe MR were more likely to receive two MitraClip devices. Immediate and long-term reduction in MR was similar regardless of the number of devices implanted at the time of the procedure.

BACKGROUND: Studies demonstrate an increase in radiation exposure with transradial approach (TRA) when compared with transfemoral approach (TFA) for coronary angiography. Given the learning curve associated with TRA, it is not known if this increased radiation exposure to patients is seen when procedures are performed by experienced operators. METHODS: We retrospectively evaluated 1,696 patients who underwent coronary angiography with or without percutaneous coronary intervention (PCI) by experienced operators at a tertiary center from October 2010 to June 2011. Experienced operators were defined as those that perform >75 PCIs/year with >95% of cases performed using the TRA or TFA approach for >/=5 years. The outcomes of interest were dose area product (DAP) and fluoroscopy time (FT). RESULTS: Of the 1,696 patients, 1,382 (81.5%) were performed by experienced femoral operators using TFA and 314 (18.5%) were performed by experienced radial operators using TRA. Most of these cases (65.4%) were diagnostic only (870 TFA and 240 TRA) with both DAP (6040 [3210-8786] vs 5019 [3377-6869] muGy.m, P = .003] and FT [6.2 [4.0-10.3] vs 3.3 [2.6-5.0] minutes, P < .001) significantly higher using TRA versus TFA. For procedures involving PCI, despite similar baseline patient, procedural and lesion characteristics, DAP and FT remained significantly higher using TRA versus TFA (19,649 [11,996-25,929] vs 15,395 [10,078-21,617] muGy.m, P = .02 and 22.1 [13.3-31.0] vs. 13.8 [9.8-20.3] minutes, P < .001). CONCLUSIONS: In a contemporary cohort of patients undergoing coronary angiography by experienced operators, TRA was associated with higher radiation exposure when compared with TFA.

OBJECTIVES: To evaluate the efficacy and safety of currently used drug eluting stents compared with each other and compared with bare metal stents in patients with diabetes. DESIGN: Mixed treatment comparison meta-analysis. DATA SOURCES AND STUDY SELECTION: PubMed, Embase, and CENTRAL were searched for randomised clinical trials, until April 2012, of four durable polymer drug eluting stents (sirolimus eluting stents, paclitaxel eluting stents, everolimus eluting stents, and zotarolimus eluting stents) compared with each other or with bare metal stents for the treatment of de novo coronary lesions and enrolling at least 50 patients with diabetes. PRIMARY OUTCOMES: Efficacy (target vessel revascularisation) and safety (death, myocardial infarction, stent thrombosis). RESULTS: From 42 trials with 22 844 patient years of follow-up, when compared with bare metal stents (reference rate ratio 1) all of the currently used drug eluting stents were associated with a significant reduction in target vessel revascularisation (37% to 69%), though the efficacy varied with the type of stent (everolimus eluting stents approximately sirolimus eluting stents>paclitaxel eluting stents approximately zotarolimus eluting stent>bare metal stents). There was about an 87% probability that everolimus eluting stents were the most efficacious compared with all others, though there were limited usable data for the zotarolimus eluting Resolute stent in patients with diabetes. Moreover, there was no increased risk of any safety outcome (including very late stent thrombosis) with any drug eluting stents compared with bare metal stents. There was about a 62% probability that the everolimus eluting stent was the safest stent for the outcome of "any" stent thrombosis. CONCLUSIONS: Among patients with diabetes treated with coronary stents all currently available drug eluting stents were efficacious without compromising safety compared with bare metal stents. There were relative differences among the drug eluting stents, such that the everolimus eluting stent was the most efficacious and safe.

AIM: To evaluate safety and utility of coronary computed tomography angiography (CCTA) compared to invasive coronary angiography (ICA) in new cardiomyopathy. METHODS: Eighteen patients (mean age 56.5 years, 10 males) who presented for evaluation of new onset heart failure with evidence of systolic dysfunction (ejection fraction < 40%) on echocardiography and recent ICA were prospectively enrolled. Patients with known coronary artery disease, atrial fibrillation, creatinine > 1.5 g/dL, and contraindication to intravenous contrast administration were excluded. CCTA was performed using a dual source 64-slice scanner. Mean heart rate was 75 beats per minute. Stenosis was graded for each coronary segment as: none, mild (< 50%), moderate (50%-70%), severe (> 70%), or non-evaluable. Ischemic cardiomyopathy (ICM) was diagnosed if severe stenosis was present in the left main, proximal left anterior descending artery, or two or more major arteries. RESULTS: Two patients were diagnosed with ICM by ICA. CCTA correctly identified 2 patients with ICM and 16 patients as non-ICM. CCTA successfully evaluated 240/246 coronary segments with an accuracy of 97.5%, sensitivity 70%, specificity 98.7%, positive predictive value of 70%, and negative predictive value of 98.7% for identifying severe stenosis on a per-segment level. CONCLUSION: Dual source 64-slice multi-detector CCTA is a safe, accurate, and non-invasive technique for diagnosing ICM in patients presenting during the acute phase of newly diagnosed cardiomyopathy.