Saundra Grant

Exploratory use of cardiovascular magnetic resonance imaging in liver transplantation: a one-stop shop for preoperative cardiohepatic evaluation.

Background Preoperative cardiovascular risk stratification in orthotopic liver transplantation candidates has proven challenging due to limitations of current noninvasive modalities. Additionally, the preoperative workup is logistically cumbersome and expensive given the need for separate cardiac, vascular, and abdominal imaging. We evaluated the feasibility of a “one-stop shop” in a magnetic resonance suite, performing assessment of cardiac structure, function, and viability, along with simultaneous evaluation of thoracoabdominal vasculature and liver anatomy. Methods In this pilot study, patients underwent steady-state free precession sequences and stress cardiac magnetic resonance (CMR), thoracoabdominal magnetic resonance angiography, and abdominal magnetic resonance imaging (MRI) on a standard MRI scanner. Pharmacologic stress was performed using regadenoson, adenosine, or dobutamine. Viability was assessed using late gadolinium enhancement. Results Over 2 years, 51 of 77 liver transplant candidates (mean age, 56 years; 35% female; mean Model for End-stage Liver Disease score, 10.8; range, 6–40) underwent MRI. All referred patients completed standard dynamic CMR, 98% completed stress CMR, 82% completed late gadolinium enhancement for viability, 94% completed liver MRI, and 88% completed magnetic resonance angiography. The mean duration of the entire study was 72 min, and 45 patients were able to complete the entire examination. Among all 51 patients, 4 required follow-up coronary angiography (3 for evidence of ischemia on perfusion CMR and 1 for postoperative ischemia), and none had flow-limiting coronary disease. Nine proceeded to orthotopic liver transplantation (mean 74 days to transplantation after MRI). There were six ascertained mortalities in the nontransplant group and one death in the transplanted group. Explant pathology confirmed 100% detection/exclusion of hepatocellular carcinoma. No complications during CMR examination were encountered. Conclusions In this proof-of-concept study, it appears feasible to perform a comprehensive, efficient, and safe preoperative liver transplant imaging in a CMR suite—a one-stop shop, even in seriously ill patients.

Does the presence of Q waves on the EKG accurately predict prior myocardial infarction when compared to cardiac magnetic resonance using late gadolinium enhancement? A cross-population study of noninfarct vs infarct patients

BACKGROUND We hypothesize that infarct detection by electrocardiogram (EKG) is inaccurate as compared with detection by magnetic resonance imaging and is potentially independent of infarct vs noninfarct status. This might have implications for societies in which initial cardiovascular testing is uniformly EKG. OBJECTIVE This study aimed to relate EKG-defined scar to cardiovascular magnetic resonance imaging (CMR)-defined scar independent of the underlying myocardial pathology. METHODS A total of 235 consecutive patients who underwent CMR-late gadolinium enhancement (LGE) with simultaneous EKG were screened for Q waves and compared with patients with a positive LGE pattern. The patients were divided into 3 groups: (1) patients with a positive infarct LGE pattern (LGE+/+; herein defined as LGE+), (2) patients with a noninfarct LGE pattern (LGE+/-), and (3) patients with a negative LGE pattern (LGE-). RESULTS While 139 of 235 patients (59%) were either LGE+ or LGE+/-, pathological Q waves were present in only 74 of 235 patients (31%). However, of these LGE+ or LGE+/- patients, only 76 (32%) had an infarct LGE pattern representing little overlap between the presence of LGE+ and Q waves. EKG sensitivity and specificity to detect infarct: 66% and 85%, respectively. However, of 24 of 74 patients (32%) with Q waves on the EKG, 66% were LGE+/- and 34% were LGE-. Importantly, 3-dimensional volume of myocardial scar was far more predictive of a Q wave than of scar transmurality. CONCLUSION EKG-defined scar, while ubiquitous for an infarct, has low sensitivity than CMR-LGE-defined scar. Unexpectedly, a significant number of pathological Q waves had absent infarct etiology, indicating high false positivity. Similarly, underrecognition of bona fide myocardial infarction frequently occurs, while 3-dimensional CMR volume of myocardial scar is far more predictive of a Q wave than of scar transmurality. This suggests that the well-regarded EKG may be a disservice when applied on a population basis, leading to inappropriate over or under downstream testing with wide socioeconomic implications.

Is cardiovascular MRI equally effective as TEE in evaluation of left atrial appendage thrombus in patients with atrial fibrillation undergoing pulmonary vein isolation

Patients with atrial fibrillation (Afib) routinely undergo a transesophageal echocardiogram (TEE) for evaluation of the left atrial appendage (LAA) to rule out thrombus prior to undergoing cardioversion or pulmonary vein isolation (PVI). Cardiac MRI (CMR) is now increasingly used for evaluation of these patients for defining pulmonary vein anatomy prior to PVI. We hypothesized that 2D and 3D non-contrast and contrast CMR is as effective as TEE in evaluating for LAA thrombus while providing simultaneous comprehensive non-invasive evaluation of the pulmonary vein anatomy within a single exam.

Can cardiac MRI be the 'crystal ball' for risk stratification in dilated cardiomyopathy? The impact of an LV mid-myocardial stripe on LVAD and transplantation risk

Patients with newly diagnosed dilated cardiomyopathy and advanced heart failure have a very high morbidity and mortality with an unpredictable clinical course. We investigated the role of CMR via LGE in this cohort of patients.

CARDIOVASCULAR MRI IS EQUALLY EFFECTIVE AS TRANSESOPHAGEAL ECHOCARDIOGRAM IN EVALUATION OF LEFT ATRIAL APPENDAGE THROMBUS IN ATRIAL FIBRILLATION: A STRATEGY FOR PULMONARY VEIN ISOLATION

Introduction: Patients with atrial fibrillation (Afib) routinely undergo TEE for evaluation of left atrial appendage (LAA) to rule out thrombus prior to undergoing cardioversion or pulmonary vein isolation. Cardiac MRI (CMR) is now increasingly used for evaluation of cardiac pts. We hypothesized that 2D and 3D non-contrast and contrast CMR is as effective as TEE in evaluating the LAA thrombus while providing simultaneous comprehensive non-invasive evaluation of the pulmonary vein anatomy within a single exam enabling pulmonary vein isolation (PVI) and routine LAA evalautions.

Dilated cardiomyopathy risk stratification; the vital role of CMR

Methods Over 24 consecutive months, 49 CMX pts were referred for standard 3D CMR (1.5 T GE) to interrogate the LV pattern, distribution and extent of DHE (MultiHance, Princeton, NJ). 18 pts met follow-up inclusion criteria for the study. Pts were categorized into: 1)+DHE/+midwall Stripe 2)+DHE/-Stripe and 3)-DHE/-Stripe. LVAD, Tx use, major adverse clinical events (MACE) and event free survival were evaluated over the next 6 months.

2046 Results of long term follow-up of mitral regurgitation following aortic valve replacement for severe aortic stenosis by cardiac MRI

Methods Cardiac MRI (CMR) was performed on 10 patients with severe but compensated AS 3 ± 2 days prior and 10 ± 3 months post AVR and at up to 3 ± 1 years after the AVR. Semi-quantitative quantification of the grade of MR was determined. Pre and post AVR, mitral valve geometry, LV geometry, mass/volume index and function were measured and compared. >2+ AR and or structural mitral pathology were excluded.

Is there concordance between LV fibrosis and RV fibrosis in patients with hypertrophic cardiomyopathy; should there be?

Background CMR has become the leading modality to define the clinical impact of hypertrophic cardiomyopathy (HCM) providing complete coverage of both ventricles with high spatial resolution. Late gadolinium enhancement (LGE) accurately identifies regions of myocardial fibrosis. Via CMR, innumerable studies have established that LVH and LGE are the predominant phenotypic expressions of HCM. It is well known that myocardial fibrosis can occur in patients with HCM and is independently linked to a poorer prognosis than those without fibrosis by CMR.

Can cardiac MRI be the index metric for risk stratification in dilated cardiomyopathy; the impact of an LV mid-myocardial stripe on subsequent risk of LVAD, transplantation and death

Summary The mid-wall intramyocardial ‘stripe’ is now shown to be robust in its prediction of subsequent need for LVAD and/or transplantion and death out to 12 months following index CMR exam. Background Patients with newly diagnosed dilated cardiomyopathy (DCM) and advanced heart failure have a very high morbidity and mortality with an unpredictable clinical course. We investigated the role of CMR via LGE (late gadolinium enhancement) in this cohort of high-risk patients. Hypothesis Utilizing cardiovascular MRI (CMR), we assessed the prognostic value of LGE in primary dilated DCM patients referred for possible transplantation/ LVAD consideration. Methods

Paradoxical changes in lumen size during progression and regression of carotid atherosclerosis

Summary Atherosclerotic changes regarding the lipid pool and frbrous cap are related to the lumen and show countgerintuitive changes; a discourse on Glagov’s Hypothesis. Background Relative changes in arterial lumen size during progression and regression of atherosclerosis particularly in response to lipid modulating therapy are largely unknown. This study was designed to investigate the effects of statin therapy on human carotid atherosclerotic lesions as measured by high-resolution Cardiac Magnetic Resonance (CMR). Methods Via CMR (1.5T GE, WI), 35 carotid arteries of 18 asymptomatic, ‘statin naive’ patients with maximum carotid stenosis >50% (mean 64±21), were imaged at baseline and following 12 months of randomized, blinded statin therapy (simvastatin 40mg or Vytorin (Ezetimibe 10mg/ simvastatin 40mg)). The effects of statins on these lesions were evaluated as changes in carotid outer wall area (OWA), lumen area (LuA), vessel wall area (VWA), lipid area (LpA) and lipid percentage (Lp%). The percentage of stenosis of each slice was determined in reference to a normal or near normal sl. Results A total of 707-2mm slices of interpretable quality were available representing 39 in vivo plaques. Among these as followed over time, 378 (53.5%) demonstrated progression while 329 (46.5%) showed regression. Among ‘Progressors’, OWA, VWA, Lp% and LuA increased (P< .001 for OWA, VWA and Lp% and 0.14 for LuA), while among ‘Regressors’, all the above parameters decreased significantly (P<.001 for all). There was no statistically significant change in any of the parameters when all contiguous slices of all carotid plaques were analyzed in a 3D fashion. Conclusions Changes in carotid plaque after lipid lowering therapy, as measured by high-resolution CMR depict a counterintuitive effect on lumen size: as VWA and LpA decrease so does the LuA. Similarly, as VWA and LpA increase so does LuA. The measurement of luminal area may not be ar eliable measure of response of carotid plaque to statin therapy, as progression of carotid atherosclerosis is associated with a paradoxical increase and regression of atherosclerosis with a paradoxical decrease in luminal area. Funding Internal.