Faculty Bibliography

BACKGROUND: In a prospective study, we previously identified plaque disruption (PD: plaque rupture or ulceration) in 38% of women with myocardial infarction (MI) without angiographically obstructive coronary artery disease (CAD), using intravascular ultrasound (IVUS). Underlying plaque morphology has not been described in these patients and may provide insight into the mechanisms of MI without obstructive CAD. METHODS: Forty-two women with MI and <50% angiographic stenosis underwent IVUS (n = 114 vessels). Analyses were performed by a blinded core laboratory. Sixteen patients had PD (14 ruptures and 5 ulcerations in 18 vessels). Plaque area, % plaque burden, lumen area stenosis, eccentricity, and remodeling index were calculated for disrupted plaques and largest plaque by area in each vessel. RESULTS: Disrupted plaques had lower % plaque burden than the largest plaque in the same vessel (31.9% vs 49.8%, P = .005) and were rarely located at the site of largest plaque (1/19). Disrupted plaques were typically fibrous and were not more eccentric or remodeled than the largest plaque in the same vessel. CONCLUSIONS: Plaque disruption was often identifiable on IVUS in women with MI without obstructive CAD. Plaque disruption in this patient population occurred in fibrous or fibrofatty plaques and, contrary to expectations based on prior studies of plaque vulnerability, did not typically occur in eccentric, outwardly remodeled, or soft plaque in these patients. Plaque disruption rarely occurred at the site of the largest plaque in the vessel. These findings suggest that the pathophysiology of PD in women with MI without angiographically obstructive CAD may be different from MI with obstructive disease and requires further investigation.

Periprocedural hyperglycemia is an independent predictor of mortality in patients who underwent percutaneous coronary intervention (PCI). However, periprocedural management of blood glucose is not standardized. The effects of routinely continuing long-acting glucose-lowering medications before coronary angiography with possible PCI on periprocedural glycemic control have not been investigated. Patients with diabetes mellitus (DM; n = 172) were randomized to continue (Continue group; n = 86) or hold (Hold group; n = 86) their clinically prescribed long-acting glucose-lowering medications before the procedure. The primary end point was glucose level on procedural access. In a subset of patients (no DM group: n = 25; Continue group: n = 25; and Hold group: n = 25), selected measures of platelet activity that change acutely were assessed. Patients with DM randomized to the Continue group had lower blood glucose levels on procedural access compared with those randomized to the Hold group (117 [97 to 151] vs 134 [117 to 172] mg/dl, p = 0.002). There were two hypoglycemic events in the Continue group and none in the Hold group, and no adverse events in either group. Selected markers of platelet activity differed across the no DM, Continue, and Hold groups (leukocyte platelet aggregates: 8.1% [7.2 to 10.4], 8.7% [6.9 to 11.4], 10.9% [8.6 to 14.7], p = 0.007; monocyte platelet aggregates: 14.0% [10.3 to 16.3], 20.8% [16.2 to 27.0], 22.5% [15.2 to 35.4], p <0.001; soluble p-selectin: 51.9 ng/ml [39.7 to 74.0], 59.1 ng/ml [46.8 to 73.2], 72.2 ng/ml [58.4 to 77.4], p = 0.014). In conclusion, routinely continuing clinically prescribed long-acting glucose-lowering medications before coronary angiography with possible PCI help achieve periprocedural euglycemia, appear safe, and should be considered as a strategy for achieving periprocedural glycemic control.

Coronary angiography is the gold standard for defining obstructive coronary disease. However, radiation exposure remains an unwanted hazard. Patients referred for coronary angiography with abdominal circumference <45 inches and glomerular filtration rate >60 ml/min were randomized to the fluorography (n = 25) or cineangiography (n = 25) group. Patients in the fluorography group underwent coronary angiography using retrospectively stored fluorography with repeat injection under cineangiography only when needed for better resolution per operator's discretion. Patients in the cineangiography group underwent coronary angiography using routine cineangiography. The primary end point was patient radiation exposure measured by radiochromic film. Secondary end points included the radiation output measurement of kerma-area product and air kerma at the interventional reference point (Ka,r) and operator radiation exposure measured by a dosimeter. Patient radiation exposure (158.2 mGy [76.5 to 210.2] vs 272.5 mGy [163.3 to 314.0], p = 0.001), kerma-area product (1,323 muGy.m(2) [826 to 1,765] vs 3,451 muGy.m(2) [2,464 to 4,818], p <0.001), and Ka,r (175 mGy [112 to 252] vs 558 mGy [313 to 621], p <0.001) were significantly lower in the fluorography compared with cineangiography group (42%, 62%, and 69% relative reduction, respectively). Operator radiation exposure trended in the same direction, although statistically nonsignificant (fluorography 2.35 muGy [1.24 to 6.30] vs cineangiography 5.03 muGy [2.48 to 7.80], p = 0.059). In conclusion, the use of fluorography in a select group of patients during coronary angiography, with repeat injection under cineangiography only when needed, was efficacious at reducing patient radiation exposure.

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.